Piston pumps and excavator hydraulic machines
Piston pumps and hydraulic motors are widely used in hydraulic drives of a number of excavators both on attachments and many full-time machines. Rotary-piston pumps of two types obtained the greatest distribution: axial-piston and radial-piston. -
Axial-piston pumps and excavators hydraulic machines - Part 1
Their kinematic basis serves a crank-connecting mechanism in which the cylinder moves parallel to its axis, and the piston moves together with the cylinder and at the same time due to the rotation of the crank shaft moves relative to the cylinder. When you turn the crank shaft to the angle of y (Fig. 105, a), the piston moves together with the cylinder for the value of A and relative to the cylinder by value. The turn of the plane of rotation of the crank shaft around the axis y (Fig. 105, b) at an angle 13 also leads to the movement of the point A, in which the finger of the crank is hingedly connected to the piston rod.
If it takes several cylinders instead of one and arrange them in the circumference of the block or drum, and the crank is replaced by the disk, the axis of which is rotated relative to the axis of the cylinders at an angle 7, with 0 4 y \u003d 90 °, the plane of rotation of the disk coincides with the plane of rotation of the crank shaft rotation. Then the concept of an axial pump will be obtained (Fig. 105, c), in which the pistons move in the presence of an angle from the axis of the cylinder block and the axis of the driving shaft.
The pump consists of a fixed distribution disk 7, rotating block 2, pistons 3, rods 4 and an inclined disk 5, hinged with a rod 4. In the distribution disk 7 arc windows 7 are made (Fig. 105, d) through which the liquid is sucked and injected pistons. Between the windows 7, jumpers BT width separating the suction cavity from the discharge cavity are provided. When the block rotates, the opening 8 of the cylinders is connected either with the cavity of the suction, or with the cavity of the discharge. When the direction of rotation of the block 2, the cavity functions are changed. To reduce the leakage of the liquid, the skid surface of the block 2 is carefully torn to the distribution disk 5. The disk 5 rotates from the shaft b, and together with the disk the block 2 of the cylinders rotates.
The angle y is usually taken equal to 12-15 °, and sometimes it reaches 30 °. If the angle 7 is permanent, then the volume supply of the pump is constant. With a change in the value of the angle 7 of the inclination of the disc 5 changes the stroke of the pistons 3 per rotor turnover and the pump feed is changed.
The circuit of the automatically adjustable axial-piston pump is shown in Fig. 106. In this pump, the feed regulator is the washer 7 associated with the shaft 3 and connected to the piston 4. On the piston, on the one hand, the spring 5 acts, and on the other is the pressure in pressure hydrolynium. When the shaft rotates 3, the washer 7 moves plungers 2, which suck the working fluid and injected it into hydrolynes. The pump feed depends on the tilt of the washer 7, that is, on the pressure in the pressure hydrolynes varying in turn from the external resistance. For low power pumps, the pump feed can also be adjusted manually by changing the washer sling, a special amplifying device is used for more powerful pumps.
Axial-piston hydraulic motors are arranged in the same way as the pumps.
Many attachment excavators use an unregulated axial-piston hydromoter pump with an inclined unit of NPA-64 (Fig. 107). A block 3 of cylinders gets rotation from the shaft / through a universal hinge 2. Shaft 1, driven by motor, relies on three ball bearings. Pistons 8 are associated with a shaft 1 rods 10\u003e whose ball heads are spilled in the flange part of the shaft. Block 3 of cylinders "Rotating on the ball bearing 9 is located with respect to the shaft 1 at an angle of 30 ° and pressed the spring 7 to the distribution disk b, which is pressed by the same force to the lid 5. The liquid is supplied and removed through the windows 4 in the lid 5. Cutting seal 11 In the front cover of the pump prevents oil leakage from the non-working pump cavity.
The pump feed for one turnover of the shaft is 64 cm3. At 1500 rpm of the shaft and operating pressure of 70 kgf / cm2, the pump feed is 96 l / min, and the volume efficiency is 0.98.
At the NPA-64 pump, the axis of the cylinder block is located at an angle to the axis of the leading shaft, which determines its name - with an inclined unit. In contrast to the axial pumps with an inclined disk, the axis of the cylinder block coincides with the axis of the driving shaft, and at an angle of the disk axis, with which the piston rods are hinged. Consider the design of an adjustable axial-piston pump with an inclined disk (Fig. 108), the peculiarity of the pump is that the shaft 2 and the inclined disk b are connected to each other with a single or tweaking cardan mechanism 7. The working volume and pump supply is adjusted by a change in inclination disk b relative to block 8 cylinders 3.
105 axial piston pump schemes:
A - piston actions,
B - operation of the pump, in - constructive, G - actions of a fixed distribution disk;
1 - fixed switchgear,
2 - Rotating block.
3 - piston,
5 - inclined disk,
7 - arc window,
8 - cylindrical hole;
A - the length of the total cross section of the arc window
106 Chart of an adjustable axial piston pump:
1 - washer,
2 - plunger,
3 - shaft,
4 - piston,
5 - Spring
In the spherical supports of the inclined disk 6 and pistons 4 are fixed by the ends of the connecting rod 5. When the connecting rod is operational, it is deflected on a small angle relative to the axis of the cylinder J, so the side component force acting on the bottom of the piston 4 is insignificant. The torque on the cylinder block is determined only by friction of the end of the block 8 of the switchgear 9. The magnitude of the moment depends on the pressure in the cylinders 3. almost almost the entire torque from the shaft 2 is transmitted to the inclined disk 6, since the pistons 4 are moved to the operating A liquid from cylinders 3. Therefore, a highly loaded element in such pumps is a cardan mechanism 7, transmitting the entire torque from the shaft 2 to the disk 6. The drive mechanism limits the angle of inclination of the disk 6 and increases the pump dimensions.
The cylinder block 8 is connected to the shaft 2 through the mechanism 7, which allows the block to self-install over the distribution disk surface 9 and transmit the torque between the disk ends and the block to the shaft 2.
One of the positive features of adjustable pumps of this type is comfortable and simple supply and removal of the working fluid.
Hydraulic Excavator System E-153 A It consists of two controls (hydrocoles), power hydraulic cylinders, oil tank with a capacity of 200 liters with filters and hydraulic pipelines with safety valves.
The power source of the hydraulic system of the working fluid is the pumping group.
The pumping group consists of two axion-plunger pumps of NPA-64 and an increase in the cylindrical gearbox that provides a nominal rotation speed of the pump shaft - 1530 rpm. Such a rotational speed with specific pump performance 64 cm3 / min provides a supply to the hydraulic effect to the actuators (power cylinders) of 96 l / min of the left pump oil and 42.5 l / min of the right pump. Power selection for pump drive is carried out from the tractor gearbox using an increasing gearbox.
The reducer is assembled in a cast cast-iron case, which is connected by the flanges to the front of the tractor transmission case, on the left in the course of the latter.
A cylindrical gear gear is sitting on the primary slotted roller, which is introduced into the gear of the tractor drive pullee and the gear gear shaft.
Three following gearbox settings are possible.
- If the primary roller and shaft of the gear rotates, both pumps work.
- If the roller rotates, and the gear shaft is disabled, only one pump works.
- If the main gear gear is removed from the gear of the tractor drive pullee, both pumps do not work.
The switching on and off the gearbox is carried out by turning the lever associated with the control roller.
Pumps are mounted on a cast-iron gearbox. Pumps are given from the tractor gearbox and the working fluid is supplied from the oil tank (200 l) under the pressure of 75 kg / cm2 through steam distributors into power cylinders. From the power cylinders, the exhaust oil by plum lilies through the filters arrives back to the tank.
Below are the hydraulic pump device ( fig. 45.). A bolt flange 7 is mounted on the pump body 1, closed with a lid 11. In the housing on the bearing supports, the drive shaft 3 with seven pistons is installed.
Rolling rods 17 pistons with its ball heads per rolling in the flange part of the driven 3.
At the second ball end of the connectors, the pistons 16 are attached in the amount of seven pieces.
The pistons are included in the cylinder block 10, which is mounted on the bearing support 9 and the effect of the spring 12 is tightly in contact with the distributor 15. The latter, in turn, the force of the same spring is tightly pressed to the lid 11. In order for the distributor to be rotated, it will stop the pins.
Rotation from the drive shaft to the cylinder block is driven by cardan 6.
The lump seal 4 placed in the front cover 2 of the housing 1 serves as an obstacle to the leakage of the working fluid from the non-working pump cavity in the drive gearbox.
The drive shaft 3 of its grinding part is connected to the gearbox and receives from the last rotation. The cylinder block 10 receives rotation from the drive shaft by means of a cardan 6.
Thanks to the inclination of the axis of the cylinder block to the axis of the drive shaft of the pistons 16, the block rotates the reciprocating movement. From the angle of inclination depends the length of the stroke of the piston and, therefore, its performance.
In this pump, the angle of inclination is constant and equal to 30 °.
To clarify the principle of operation of the pump, consider the work of only one piston.
Piston 16 for one turnover of the cylinder block, one double stroke.
The leftmost and right state corresponds to the start of suction and discharge. When the piston moves to the left (when the block is rotated clockwise), suction occurs, when moving to the right - discharge.
The suction and discharge positions are coordinated with the location of the opening 14 relative to the suction and discharge grooves (the oval grooves, they are not visible in the figure) of the distributor 15.
During the absorption process, the block 14 of the block occupies a position against the grooves of the absorption of the distributor connected to the suction channel. In the injection, the hole 14 occupies a position against discharge grooves connected to the discharge channel.
At the same time, the remaining six pistons are also working.
The oil from the working cavity of the pump is completely discharged into the tank of the working fluid through the drainage opening 5.
Increased pressure over the permissible is limited to two fuse valves installed on each pump.
Hydraulic cylinders are designed to carry out all movements of the excavator working bodies. On the e-153A excavator Nine cylinders are installed ( fig. 47.) Piston type with rectilinear return-transit movement rod.
During the movement of the stem, the cylinder cavity is connected to the injection, and the other with the drain highway. The direction of the rod movement is set by the lever of the hydraulic control box. Power cylinders are the executive bodies of the hydroprower of the machine.
All cylinders have an inner diameter of 80 mm, with the exception of the boom cylinder, the diameter of which is 120 mm. The diameter of the rod in all cylinders is 55 mm.
All cylinders (except for the rotation cylinder) are dual-action cylinders.
Double-acting hydraulic cylinder ( fig. 46.) Consists of the following main parts: pipes 1, rod 29 with piston 9, front cover 27 and rear - 5, angular fittings 7 and seals.
Pipe 1, creating the main working volume of the cylinder, has a thoroughly treated inner surface. At the ends of the pipe there is an outer thread for mounting to drink covers 27 and 5.
The bulldozer cylinder additionally has a thread in the middle of the pipe. Additional thread is necessary for attaching traverses with pinges (Fig. 76).
Cylinder rods 29 arrows, handles, bucket and turning mechanism ( fig. 46.) Hollow and consist of pipe 28, shank 13 and ear 21, welded with each other.
The rods of the remaining cylinders are made of solid metal.
The cylinder rod moves in the bronze sleeve 24 front cover.
For better wear-resistant and anti-corrosion, the working surface of the rod is chromed.
A piston 9 with two cuffs 10 was planted on a free shank of the rod, supported by the stops 11 and a cone 12.
The cone, together with the ring, forms a damper, which serves to mitigate the blow at the end of the course when the rod is extended to the extreme position.
Fastening the piston, stops and cones is carried out with nut 4 and a locking washer 3.
The piston 9 on both sides has a ledge for placing a cuff 16 in them. Inside the piston there is a ring groove with a sealing ring 2, which serves to prevent the flow of fluid from one cylinder cavity to another rod. On the shank of the rod there is a copus, which in the extreme left position enters the opening of the back cover and forms a damper, a softening strike at the end of the course.
The piston serves as a support for the rod, and together with the seals it reliably separates the cylinder into two cavities, into which one in one, then oil comes into another.
The rear covers of all cylinders, with the exception of the cylinder of the bulldozer, deaf and in its tail has a ear with a pressed hardened sleeve 6 for a cylinder hinge connection.
The threaded part of the cover has an annular groove with a sealing ring 8, which serves to prevent leakage of liquid from the cylinder.
The rear cover of the bulldozer cylinder has a central through connection for the supply of fluid through the fitting attached to the lid bolted.
The 3Dless arrow cylinder covers, handles, bucket and support shoes have central and lateral drills that are interconnected and forming the working fluid channel.
Rear cylinder covers have channels, similar to the channels in the cylinder covers of the boom, handle and support shoes.
Through the specified channels, the non-working cavity of the cylinders using the 7, the steel pipe and the sapunion are connected together.
The front cover 27 is screwed onto the pipes. For the passage of the rod in the lid there is a hole with a bronze sleeve pressed into it 24. Inside the cover has two ledges: the cuff 16 is removed, maintained from the axial displacement of the cable ring 25 and the retaining spring ring 26; In the second - removes ring 14, forms together with a cone 12 on the damper stem and the lifting stroke of the piston. On the other hand, the cover 18 is screwed onto the front cover, which is fastened with a washer 19 and a mumbling 20.
On the side of the lid there is a hole for translating the liquid through the fitting.
All covers have slots for the key and stopped with locknuts.
The angular fitting is attached to the cylinder bolts and is condensed with a rubber ring 15.
For smooth operation of the hydraulic cylinders, it is necessary to replace the worn seals and mudels in a timely manner. Watch the cylinder rods do not have care and scratches. Periodically tighten the compounds of fittings, since in the presence of a gap between the fitting and the kood, the seal is rapidly destroyed.
Hydrodistributors, or control boxes are the main nodes of the excavator control mechanisms. They are intended for the distribution of the working fluid coming from the feed hydraulic pumps to the power cylinders, which there are nine pieces on the excavator ( fig. 47.). All of them have their own purpose:
- a) the boom cylinder is designed for its lifting and lowering;
- b) two cylinders of the handle - for the message of the movement of the handle along the radius in one direction or the other;
- c) the bucket cylinder - for turning the bucket (when working in a reverse shovel) and for opening the bottom (with a direct shovel);
- d) the bulldozer cylinder - for lowering or lifting the dump;
- e) two turn cylinders - for the rotational movement of the swivel column;
- e) two cylinders of support shoes - to lift and lower the latter during the excavation.
Left box ( fig. 47.), distributing the working fluid on the cylinders of the boom, the support shoes and the rotary column, consists of three pairs of rigidly interconnected chokes and spools 1. The shunting spool 2 serves to connect the working cavities of the force cylinder of the boom among themselves and with the hydraulic drain line. Four spring zero-installer 4 return hydraulic drive controls to neutral (zero) position. The speed controller 3 automatically levels the pressure on the nourishing pump and the actuators.
The right box associated with the right rear pump distributes the working fluid on the cylinders of the handle, a bucket and a bulldozer. In this box there is no shunting spool; There is one shut-off valve 6 and two safety valves 7 and 8. Otherwise, the design of the boxes is equally.
To work one of the excavator mechanisms, it is necessary to move the corresponding folding choke - the spool up or down, depending on which the direction should move the mechanism. The left component of this pair is the choke, changing the flow of oil in size, and the right component is a spool that changes the oil notch but the direction.
Oil tank 17 ( fig. 47.) It is a strain-welded design of sheet steel with a thickness of 1.5 mm. It consists of a rectangular casing, within which four partitions are welded, designed to calm the working fluid and the separation of the emulsion.
From above, the tank is closed with a stamped lid with a gasket with a oilproof rubber. In the center of the lid there is a rectangular hole where the filter tank is inserted 12, which serves for partial oil treatment.
In the lower part of the tank, two fittings are welded through which the oil enters the pumps, and there is a hole, closed by a plug, through which the oil from the tank is drained as needed.
From side sides, three cylindrical wire filters are inserted into the tank. The tank has an observation window 10, which allows you to monitor the level of working fluid in the tank. The conical funnels 11 give the flow direction of the working fluid and increase its speed. The safety valve 8 in the filter tank is adjusted for a pressure of 1.5 kg / cm2. With greater pressure, the oil flows through the drain hole of the valve.
All tank connections are closed hermetically closed, and only through the air filter, the inner cavity of the tank is associated with the atmosphere to avoid increase in pressure in the tank.
Support of the working fluid from pumps to hydrocoles, hydraulic cylinders and a plums into the tank are carried out by means of steel seamless pipes, rubber hoses and connecting reinforcement.
Pipes with a diameter of 28 x 3 are installed on the injection and power line, the pipe 35 x 2 is mounted on the power total highway from the distributors to the Baku of the working fluid. The remaining hydroplands are made of pipes with a diameter of 22 x 2 mm. The underwrite of the working fluid from the tank to the pumps was carried out by two durated hoses with a diameter of 25 x 39.5.
In places where the working fluid is supplied to the movable mechanisms of the excavator, high pressure hoses are used. The hoses with a diameter of 20 x 38 are installed only on the boom cylinder and handles, the hoses with a diameter of 12 x 25 - on all other cylinders.
All elements of the hydroinetas - pipes, hoses are connected to each other with the help of fitting compounds 7 ( fig. 46.).
Hydraulic transfer of road machines
Hydraulic transmissions were widely used in road machines, displacing mechanical due to significant advantages: the ability to transmit high power; stepless transmission of efforts; the possibility of branching the stream of power from one engine to various working bodies; a tight connection with the mechanisms of working bodies, ensuring the possibility of their forced blindness and fixing, which is especially important for cutting organs of earthmoving machines; ensuring accurate control of the speed and reversal of the movement of the working bodies rather simple and convenient control of the handles of distribution devices; Opportunities to design any transmissions of machines without bulky cardan transmissions and compose them using unified elements and wide use of automated devices.
In hydraulic transmissions, the working fluid transmitting energy is a working fluid. As a working fluid, mineral oils of certain viscosities are used with pro-ivnosny, antioxidant, antiphen and thickening additives that improve the physical and operational properties of oils. An industrial IC-30 and MS-20 oil applies with a viscosity at a temperature of 100 ° C 8-20 CST (the temperature of frozen -20 -40 ° C). To improve the performance and durability of the machine industry, special hydraulic oils of MG-20 and MG-30 are produced, as well as the Navy (the temperature of -60 ° C), intended for all-season exploitation of hydraulic systems of road, construction, logging and other machines and ensuring their work also in Northern regions, areas of Siberia and the Far East.
Hydrotolders on the principle of action are divided into hydrostatic (hydro-volume) and hydrodynamic. In hydrostatic transmissions, the pressure of the working fluid is used (from the pump) transformed into a progressive-return mechanical movement using hydraulic cylinders or to rotational movement using hydraulic motors (Fig. 1.14). In hydrodynamic transmissions, the torque is transmitted by changing the number of working fluid flowing into the working wheels enclosed in the total cavity and the functions of the centrifugal pump and the turbine (hydromeuft and torque converters).
Fig. 1.14. Schemes of hydrostatic gear:
a - with a hydraulic cylinder; b - with hydromotor; 1 - hydraulic cylinder; 2 - pipeline; 3 - hydraulic distributor; 4 - pump; 5 - drive shaft; 6 - liquid tank; 7 - Hydromotor
The hydrostatic transmissions are performed both in the open and closed (closed) schemes with constant and variable feed pumps (unregulated and adjustable). In the open circuits, the liquid circulating in the system, after triggering, in the power element of the drive returns to the tank, located at atmospheric pressure (Fig. 1.14). In closed circuits, the circulating liquid after the triggement is sent to the pump. To eliminate the breaks of the jet, cavitation and leaks in a closed system, a feedback is made due to a small pressure from the feed tank included in the hydraulic system.
In schemes with permanent feed pumps, the speed control of the operational velocities is carried out by changing the cross sections of chokes or the incomplete inclusion of distributors spools. In diagrams with variable feed pumps, the speed control is carried out by changing the working volume of the pump. The throttle control circuits are simpler, however, for the most loaded machines and when transmitting high power it is recommended to use schemes with volume control system.
Recently, hydrostatic traction is widely used in road vehicles. For the first time, such a hydrotransmission was applied on a small-sized tractor (see Fig. 1.4). Such a tractor with a set of hinged equipment is intended for auxiliary work in various sectors of the national economy. It is a short-base car, the power of a diesel engine is 16 liters. C, the largest traction force is 1200 kgf, movement speed back and forth - from zero to 14.5 km / h, base 880 mm\u003e Palute 1100 mm, weight 1640 kg.
The hydrostatic transmission circuit of the tractor is shown in Fig. 1.15. The engine through a centrifugal clutch and a distributing gearbox reports moving two pumps that feed the hydraulic machines according to the right and left side of the machine.
Fig. 1.15. Locking diagram of hydrostatic transmission of a small-sized tractor with an on-board turn:
1 - Fist; 2 - centrifugal coupling; 3 - distribution gearbox; 4 - PUBLIC PUMP; 5 - hydraulicel; 6, 16 - high pressure pipelines; 7 - Main filter; 8 - hydromotor stroke; 9 - valve box; 10, 11 - automatic valves; 12 - check valve; 13, 14 - safety valves; 16 - in the hydraulic pump of the flow variable) 17 - gear gear gear gear
The torque of the hydraulic motor increases the gear onboard gearbox and is transmitted to the front and rear wheels of each side. All wheels tractor are leading. The hydraulic transmission scheme of each side includes a pump, a hydraulic engine, a hydraulic switch, a fuel pump, a trunk filter, a valve box, high pressure pipelines.
When the pump is running, the working fluid under pressure, depending on the overcome resistance, enters the hydraulic engine, leads its shaft into rotation and then returns to the pump.
The leakage of it through the gaps in the conjugate details is compensated by the feed pump embedded in the housing of the traction pump. Control is carried out automatically valves. The working fluid for it is fed to the highway, which is drain. If there is no need for a feedback, then the entire consumption of the feed pump is directed to the plum in the tank through the valve. Safety valves limit the maximum allowable pressure in the system, equal to 160. kgf / cm2. Purpose pressure is maintained at 3-6 kgf / cm2.
Fig. 1.16. Scheme Hydromuft:
1 - presenter; 2 - pumping wheel; 3 - body; 4 - turbine wheel; 5 - slave shaft
The pump variable pump can change the minute supply of the working fluid, i.e., change the suction and discharge lines. The rotation frequency of the hydraulic shaft is directly proportional to the pump feed: the larger the fluid, the higher the speed, and vice versa. Installing the pump to zero feed leads to complete braking.
Thus, the hydrostatic transmission entirely eliminates the clutch, gearbox, main gear, drive shaft, differential and brakes. The functions of all these mechanisms are performed by combining the operation of the pump of the supply and hydromotor.
Hydrostatic transmissions - have the following advantages: Full use of engine power on all operational modes and protection from overload; Good starting characteristic and the presence of so-called creeping speed with a large strength of thrust; stepless, smooth speed control on the entire range from zero to maximum and back; high maneuverability, simplicity of management and maintenance, self-adability; the absence of rigid kinematic ties between transmission elements; Independence of the engine location with pump and hydraulic motigaves on the chassis, i.e. favorable conditions for choosing the most rational layout of the machine.
Hydrodynamic transmissions as the simplest mechanism have hydromeflua (Fig. 1.16), consisting of two working wheels, pumping and turbine, each of which has flat radial blades. The pumping wheel is connected to the drive shaft, driven by the engine; The turbine wheel with the slave shaft is connected to the gearbox. Thus, there is no rigid mechanical connection between the engine and gearbox.
Fig. 1.17. U358011ak hydrotransformer:
1 - rotor; 2 - disk; 3 - a glass; 4 - reactor; 5 - case; 6 - turbine wheel; 7 - pumping wheel; 8 - lid; 9, 10 - sealing rings; 11 - slave shaft; 12 - fat; 13 - the mechanism of free move; 14 - presenter shaft
If the motor shaft rotates, the pumping wheel throws the working fluid in the coupling, to the periphery, where it hits the turbine wheel. Here she gives her kinetic energy and, passing between the turbine blades, it gets again in the pumping wheel. As soon as the torque transmitted to the turbine will turn out to be greater than the resistance, the slave shaft will start rotating.
Since only two operating wheels in the hydromuleuft, then under all operating conditions, the torque will be equal to them, only the ratio frequency ratio changes. The difference of these frequencies, related to the speed of rotation of the pumping wheel, is called sliding, and the ratio of the frequency of rotation of the turbine and pumping wheels is the efficiency of hydromeflues. Maximum efficiency reaches 98%. Hydromefta provides smooth start of the machine from the place and a decrease in dynamic loads in the transmission.
Hydrodynamic transmissions in the form of hydrotransformers are widely used on tractors, bulldozers, loaders, high-drivers, rinks and other construction and road machines. The hydrotransformer (Fig. 1.17) operates similarly to the hydromeflu.
The pumping wheel sitting by the rotor on the drive shaft connected to the engine creates a circulating fluid flow transmitting energy from the pumping wheel to the turbine. The latter is connected to the slave and with a transmission. An additional fixed impeller - the reactor allows you to have torque on a turbine wheel greater than on the pump. The degree of increasing torque on the turbine wheel depends on the gear ratio (the ratio of the speed of turbine and pumping wheels). When the frequency of rotation of the slave shaft increases to the frequency of rotation of the engine, the roller mechanism of the free stroke blocks the driven and leading parts of the hydrotransformer, providing direct transmission of power from the engine to the slave shaft. Seal inside the rotor is carried out by two pairs of cast iron rings.
The torque will be maximal when the turbine wheel does not rotate (stop mode), minimal - on idle mode. With an increase in the external resistance, the torque on the drive shaft of the hydrotransformer automatically increases compared to the engine torque several times (up to 4-5 times in simple and up to 11 times in more complex designs). As a result, the use of the power of the internal combustion engine with variable loads on the actuators is increased. Automation of transmissions in the presence of hydrotransformers is greatly simplified.
When the external loads change the torque converter completely protects the engine from overloads, which cannot even stop when the transmission stops.
In addition to automatic regulation, the torque converter also provides controlled speed control and torque. In particular, when adjusting the speeds, mounting velocities for crane equipment are easily achieved.
The described hydrotransformer (U358011A) is installed on self-propelled road vehicles with a power of 130-15o l. from.
Pumps and hydraulic motors. In hydraulic gears, gear, blade and axial-piston pumps are used - to convert mechanical energy into the energy of the fluid flow and hydraulic motors (reversible pumps) - to convert the fluid stream energy into mechanical energy. The main parameters of the pumps and hydraulic motors are the volume of the working fluid, displaced in one turn (or double piston stroke), the nominal pressure and the nominal speed of rotation, and the auxiliary - the nominal feed or the flow rate of the working fluid 'rated torque, as well as the total efficiency.
The gear pump (Fig. 1.18) has two cylinders - ether gears, made at the same time with shafts that are enclosed in an aluminum case.
Fig. 1.18. NSh-U series gear pump:
1, 2 - stop rings of seals; 3 - seal; 4 - O-shaped seals; 5 - leading, gear; 6 - body; 7 - Bronze bearing bushings; 8 driven gear; 9 - bolt fastening of the lid; 10 - Cover
The protruding end of the drive shaft is connected by slots with the drive device. Shafts are rotated in bronze sleeves, which simultaneously serve as seals of the end surfaces of the gears. The pump provides hydraulic compensation of the end gaps, due to which the high volume efficiency of the pump is still preserved during operation. The protruding shaft has seals. Pumps are mounted with bolts to the lid.
Table 1.7.
Technical characteristics of gear pumps 
Fig. 1.19. Bandal (Sewberry) MG-16 series pump:
1 - blade; 2 - holes; 3 - stator; 4 - shaft; 5 - cuff; 6 - ball bearings; 7 - drainage hole; 8 - cavities under blades; 9 - rubber ring) 10 - drain hole; 11 - drain cavity; 12 - ring protrusion; 13 - lid); 14 - Spring; 15 - spool; 16 - rear disk; 17 - box; 18 - cavity; 19 - High pressure fluid hole; 20 - Hole in the rear disc 21 - rotor; 22 - front disk; 23 - Ring Channel; 24 - drilling hole; 25 - housing
Gear pumps are produced by the NSh series (Table 1.7), and the pumps of the first three stamps are completely unified by design and differ only to the width of the gear wheels; The rest of their details, with the exception of the hull, are interchangeable. NSh pumps can be performed reversible and can work as hydrobotes.
In the blade (gaming) pump (Fig. 1.19), rotating parts have a small moment of inertia, which allows you to change the speed with high accelerations, with minor pressure increases. The principle of its action lies in the fact that the rotating rotor for the help of savber blades, freely sliding in the grooves, sucks fluid into the space between the blades through the supplying hole and supplies it into the drain cavity further through the squeeze hole to the working mechanisms.
Bandal pumps can also be made reversible and used to convert the fluid stream energy into the mechanical energy of the rotational motion of the shaft. The characteristics of the pumps is given in Table. 1.8.
Axial-piston pumps were used mainly in hydraulic pressure with high pressure in the system and relatively high facilities (20 liters. And more). They allow short-term overload and work with high efficiency. The pumps of this type are sensitive to oil pollution and therefore, when designing hydraulic drives with such pumps, it is possible to thoroughly filter fluid.
Table 1.8.
Technical characteristics of blade (gate) pumps 
The type 207 pump (Fig. 1.20) consists of a drive shaft, seven pistons with connecting rods, radial and tweed-dial-resistant ball bearings, a rotor, which is centered by a spherical distributor and central spike. In one turn of the drive shaft, each piston makes one double move, while the piston coming out of the rotor sucks the working fluid into the exempted volume, and when moving in the opposite direction, liquid displaces the fluid into the pressure line. The change in the value and direction of the flow of the working fluid (reversal of the pump) is carried out by changing the angle of the tilt of the rotary housing. With an increase in the deviation of the rotary housing from the position in which the axis of the drive shaft coincides with the axis of the rotor, the stroke of the pistons increases, and the pump feed changes.
Fig. 1.20. An axial piston adjustable pump type 207:
1 - drive shaft; 2, 3 - ball bearings; 4 - rod; 5 - piston; 6 - rotor; 7 - spherical distributor; 8 - swivel body; 9 - Central Schip
Table 1.9.
Technical characteristics of axial-piston adjustable pumps 
Pumps produce various feed and power (Table 1.9) and in various design versions: with different ways of attachment, with feedback, with check valves and with power regulators of type 400 and 412. Power controls automatically provide a change in the angle of inclination of the rotary housing depending on the pressure , Saving a constant drive power at a certain rotational speed frequency.
To ensure a greater supply, dual pumps of type 223 (Table 1.9) are released, consisting of two unified pumping nodes of the type 207 pump, installed in parallel in a common case.
Axial-piston unregulated type 210 pumps (Fig. 1.21) are reversible and can be used as hydraulic motors. The design of the pumping unit in these pumps is similar to the type 207 pump. Pumps-hydromotors of type 210 are produced by different feed and power (Table 1.10) and, like type 207 pumps, in various design versions. The direction of rotation of the driving shaft of the pump is the right (from the side of the shaft), and for the hydromotor - the right and left.
Fig. 1.21. Axial-piston unregulated type 210 pump:
1 -B drive shaft; 2, 3 - ball bearings; 4 - swivel washer; 5 - Shatuz 6 -A piston; 7 - rotor; 8 - spherical distributor; 9 - lid; 10 - central spike; 11 - Corpus
NPA-64 pump is produced in one design; It is a prototype of the design of the pumps of the family of 210.
Hydraulic cylinders. In mechanical engineering, power hydraulic cylinders are used to convert the operating fluid pressure into the mechanical operation of the mechanisms with reciprocating motion.
Table 1.10
Technical characteristics of axial-piston unregulated hydromotor pumps 
According to the principle of operation, the hydraulic cylinders are one-sided and bilateral action. The first develops the force in only one direction - on the piston rod piston or plunger. The reverse move is performed under the action of the load of that part of the machine with which the rod or plunger is conjugated. Such cylinders include telescopic, providing a large move due to the extension of telescopic rods.
Bilateral cylinders operate under the influence of fluid pressure in both directions and are with a bilateral (through) rod. In fig. 1.22 shows the most widely used normalized bilateral hydraulic cylinder. It has a housing, which placed a movable piston, fixed on the rod using a crown nut and a pin. The piston is sealed in the cuff cuff and the rubber ring of the round section, inserted into the rod of the rod. Cuffs pressed against cylinder walls with discs. The housing on one side is closed with a welded head, on the other, the screwed cover with the buxes, through which the rod with an eye on the end passes. Stem seal is also carried out with a disk cuff combined with a rubber ring of round. The main load is perceived by the cuff, and the sealing ring having a preliminary tension provides a tightness of the moving connection. To increase the durability of the centenary seal before it is installed a protective fluoroplastic washer.
The outlet of the rod is sealed with a seaside seal, cleansing a rod from sticking dust and dirt. There are channels and cutting holes in the cylinder head and cutting holes to attach the supply oil pipes. Drains in the cooking cylinder and stock are used to attach the cylinder by hinges to the supporting structures and working bodies. When the oil is applied to the piston cavity of the cylinder, the rod is extended, and when the ride cavity is supplied, it is drawn into the cylinder. At the end of the stroke of the shank shank, and at the end of the opposite stroke - the stem sleeve is drilled into the boring of the head and the cover, leaving the narrow ring gaps to displace the fluid. Resistance to the passage of the liquid in these gaps slows down the stroke of the piston and softens (damping) the blow when it is stopped into the head and the case cover.
In accordance with GOST, the main sizes of the unified hydraulic cylinders g in the inner diameter of the cylinder is from 40 to 220 mm with different lengths and moves of the rod for pressure 160-200 kgf / cm2. Each hydraulic cylinder sizer has three main versions: with eyelashes on the rod and cylinder head with bearings; in the drying on the rod and the pin on the cylinder for the implementation of its swing in the same plane; With a rod having a threaded hole or ending, and on the end of the cylinder head - threaded holes for the bolts for fastening the working elements.
The hydraulic distributors control the operation of hydrodic hydraulic hydraulic engineers, direct and block oil streams in pipelines connecting the hydraulic system units. Apply most often golden distributors, which are produced in two versions; Monoblock and sectional. At the monoblock distributor, all spool sections are made in one cast case, the number of sections is constant. The sectional distributor has each spool in a separate case (sections) attached to the same adjacent sections. The number of sections of the collapsible distributor can be reduced or increased by shifting. In operation, with a malfunction of one spool, one section can be replaced, without marriage in general the entire distributor.
The monoblock three-section distributor (REA. 1.23) has a housing in which three spools and an overhead valve are installed, based on the saddle. Through the handles installed in the lid, the driver rearranges spools into one of the four work positions: neutral, floating, lifting and lowering the working body. In each position, besides neutral, the spool is fixed by a special device, and in neutral - return (zero-installation) spring.
From fixed lifting and lowering positions, the spool returns to neutral automatically or manually. Fixing and return devices are closed with a lid attached from below to the body bolts. The spool has five ducts, an axial opening in the lower end and a transverse hole in the upper end under the ball leash. The transverse channel connects the axial opening of the spool with the cavity of the high pressure of the case in the lifting and lowering positions.
Fig. 1.23. Monoblock three-piece hydraulic distributor with manual control!
1 - upper cover; 2 - spool; 3 -. housing; 4 - booster; 5 - Sukharik; 6 - sleeve; 7 - Case of clamps; 8 - lock; 9 - shaped sleeve; 10 - Returning spring; 11 - a glass of springs; 12 - spool screw; 13 - bottom cover; 14 w. Saddle of the bypass valve; 15 - bypass valve; 16 -Rukotka
The valve ball through a booster and the sugar market pressed the spring to the end of the spool hole, connected to its surface with a transverse channel. The spool covers a sleeve connected to a cracker with a pin that passed through the oblong windows of the spool.
As an increase in the pressure system to the maximum valve ball is pressed down under the action of a fluid, posting through the transverse channel from the lifting cavity or lowering an axial opening of the spool. At the same time, the booster moves down Sukharik 5 together with the sleeve until it stops in the sleeve. The liquid opens the exit to the drain cavity, and the pressure in the discharge cavity cavity decreases, the valve 15 cuts the drain cavity from the discharge cavity, as it is constantly pressed the spring to the saddle. Valve's belt has a hole and a ring gap in the boring of the housing, which communicate the cavity of the discharge and control.
When working with normal pressure in the cavities above and under the belt of the bypass valve, the same pressure is set, as these cavities are communicated by the ring gap and the holes in the belt. Details 7-12 make up a device for fixing the positions of the spool.
Pa Fig. 1.24 shows the positions of the details of the fixing device in relation to the operating positions of the spool.
Fig. 1.24. Scheme of the locking device of the spool of the monoblock hydraulic distributor:
a - neutral position; b - lift; in - lowering; g - floating position; 1 - release sleeve; 2 - upper fixture spring; 3 - Case of the lock; 4 - lower fixture spring; 5 - support sleeve; 6 - springs sleeve; 7 - spring; 8 - bottom glass of springs; 9 - screw; 10 - Lower distributor cover; 11 ~ distributor housing; 12 - spool; 13 - omitting cavity
The neutral position of the spool is fixed by the spring, squeezing the glass and the sleeve. In the remaining three positions, the spring is compressed more and seeks to distribute to return the spool to the neutral position. In these positions, ring fixture springs are seen in the spool of the spool and stop it relative to the case.
The driver can return the spool in the neutral position. When the handle moves, the spool shifts from the place, the ring springs are pressed from the spool of the spool, and. It returns to the neutral position of the squeezing spring.
Automatically, the spool returns to a neutral position with an increase in pressure in the climb cavities or lowering to the maximum. In this case, the inner ball of the spool presses the sleeve down, and the end of this sleeve pushes the ring spring into the housing flow. The spool is freed from the stall. Further movement of the spool to the neutral position is carried out by the spring, acting on the spool through the sleeve and a glass, held on the spool with a screw. Known dispensers with ball locks instead of ring springs and with a modified booster design and ball valve.
With the neutral position of the spool, the cavity above the belt of the bypass valve is connected to the drain cavity of the valve distributor. In this case, the pressure in the control cavity decreases compared with the pressure in the injection cavity, due to which the valve rises, opening the path to the drain, and the spool cuts off the cavity of the actuator (or injection and drain oil hydrogenation) from the pressure and drain pipelines of the system.
In the lifting position of the working body, the spool connects the pressure valve with the corresponding cavity of the cylinder and at the same time another cavity of the cylinder with the drain channel of the distributor. At the same time, it overlaps the channel of the control cavity over the belt of the bypass valve, so that the pressure in it and in the discharge cavity (under the valve gauge) is aligned, the spring presses the valve to the saddle, which cuts the drain cavity from the discharge cavity.
In the position of lowering the working body, the spool changes to the opposite compound of the appendix of the head and drain with the cavities of the actuator cylinder. At the same time, it simultaneously overlaps the cavity channel of the bypass valve, so that the valve is set to the termination position.
In the floating position of the working body, the spool compresses from the pressure channel of the distributor both cavities of the actuator and combines them with a drain cavity. At the same time, it connects the channel of the control valve control cavity with the distributor drain channel. In this case, the pressure over the belt of the valve decreases, the valve is raised from the saddle, squeezing the spring and opening the water from the pressure cavity to the drain cavity.
Distributors of other types and sizes are constructively different from the layout and shape of the channels and cavities, belt and grooves of spools, as well as layout of the bypass and safety valves. There are three-position distributors who have no floating position of the spool. For controlling hydrobotors, the floating position of the spool is not required. The rotation of the engine in the forward and reverse directions is controlled by the installation of the spool in one of the two extreme positions.
For tractor equipment and road machines, monoblock distributors with a capacity of 75 l / min are widely used: two-rod type P-75-B2A and three-rod r-75-sissing, as well as three-rod distributors of the P-150-V / min.
In fig. 1.25 shows a typical (normalized) sectional dispenser with manual control, consisting of a pressure, working three-position, working four-position and drain sections. With the neutral position of the spools of working sections, the liquid coming from the pump on the overflow canal is freely merged into the tank. When the spool is moving into one of the working positions, the overlapped channel is overlapped with the simultaneous discovery of pressure and drain channels, which are alternately connected to the removal to hydraulic cylinders or hydraulic modes.
Fig. 1.25. Sectional dispenser with manual control:
1 - pressure section; 2 - working three-positioned section; 3, 5 - spools; 4 - working four-position section; 6 - drain section; 7 - taps; 8-protection valve; 9 - overflow canal; 10 - drain channel; 11 - Valley channel; 12 - check valve
When moving the spool of the four-position section in a floating position, the pressure channel is closed, the overflow canal is open, and the drain channels are connected to the discharges.
In the pressure section, a fuse of a differential valve, which limits the pressure in the system, and the check valve, eliminating the countercuses of the working fluid from the hydraulic manner during the inclusion of the spool, is built into the pressure selection.
Three-position and four-position work sections differ only in the sewage system of the spool. For the working three-position sections, if necessary, you can connect the block valves and a remote control spool. The distributors are collected from individual unified sections - pressure workers (various purposes), intermediate and drain. The distributor sections are tightened with bolts. Between the sections there are sealing plates with holes in which round rubber rings are installed, sealing joints. A certain thickness of the plates allows when tightening the bolts to have a single deformation of the rubber rings across the entire sections of the section of the section. Various layouts of distributors are shown on hydraulic circuits when describing machines.
Driving fluid flow control devices. These include reversible spools, valves, chokes, filters, pipelines and connecting fittings.
The reversible spool is a single-section three-position distributor (one neutral and two operating positions) and serves to reversal the flow of working fluid and changes in the direction of movement of actuators. Reversible spools can be with manual (type G-74) and electro-hydraulic control (type G73).
Electro-hydraulic spools have two electromagnets connected to spools of controls that are bypassed liquid to the main spool. Such spools (type zsu) are often used in automation systems.
Valves and chokes are designed to protect hydraulic systems from excessive pressure of the working fluid. Safety valves (type G-52) are used, safety valves with overflow spool and check valves (type M-51), designed for hydraulic systems in which the flow of the working fluid is passed only in one direction.
Throtes (such as M-55, etc.) are designed to regulate the speed of movement of the working organs by changing the flow of the working fluid. Apply chokes in conjunction with the regulator, which ensures the uniform speed of movement of the working bodies, regardless of the load.
Filters are designed to clean the working fluid from mechanical impurities (with the subtlety of filtration 25, 40 and 63 μm) in the hydraulic systems of the machines and are installed in the highway (separately mounted) or in the tanks of the working fluid. The filter is a glass with a lid and a tight plug. Inside the glass is a hollow rod, which establishes a normalized set of mesh filtering discs or a paper filter element. Filtering discs are dial to the rod and tighten the bolt. The assembled filter-bottle is written into the lid. A paper filter element is a corrugated cylinder from filter paper with a sublayer mesh, connected by the ends with metal covers with epoxy resin. In the lids, the holes for the supply and removal of the fluid are arranged, and the bypass valve is mounted. Diffsion passes through the filter element falls into the hollow rod and purified goes into the tank or in the highway.
Pipelines and connecting fittings. The nominal passage of pipelines and their compounds should, as a rule, should be equal to the inner diameter of the pipes and channels of the connecting reinforcement. The most common nominal internal diameters of pipelines 25, 32, 40 mm and less often 50 and 63 mm. Rated pressure of 160-200 kgf / cm2. Hydraulic drives are designed for nominal pressure 320 and 400 kgf / cm2, which significantly reduces the size of pipelines and hydraulic cylinders.
Up to size 40 mm, the maintenance of steel pipes are most commonly used, flange connections are used for the dimensions above the specified. Rigid pipelines are manufactured from steel alloyed pipes. Connect the pipelines by cutting the rings, which when tightening tightly crimped around the pipe. Thus, the compound comprising a pipe, a cape nut, cut ring and a fitting, can be repeatedly disassembled and collected without loss of tightness. For mobility of the connection of rigid pipelines, rotary connections are used.
Hydraulic equipment E-153 excavator
The schematic diagram of the hydraulic system of the E-153 excavator is presented in Fig. 1. Each hydraulic system node is made separately and installed on a specific place. All system nodes are interconnected by high pressure oil. The tank for the working fluid is mounted on special brackets on the left side along the tractor and is fixed with tape steps. Between the tank and the bracket, be sure to place felt pads, which protect the walls of the tank from the breakdown in the contact places with the brackets.
Below the tank on the case of the transmission box, the drive of axial-plunger pumps is installed. Each pump is connected to the tank of the working fluid with a separate oil pipeline of low pressure. The front pump of the high-pressure oil pipeline is connected to a large junction box, and the rear pump with a small junction box.
Distribution boxes are mounted and attached on a special welded frame, which is attached to the rear wall of the housing of the tractor's rear axle. The frame also provides a reliable fastening of the hydraulaging levers and the brackets of the wings of the rear wheels of the tractor.
Fig. 1. Circuit diagram of hydraulic equipment E-153 excavator
All power cylinders of the hydraulic system are attached directly on the working body or on the work equipment nodes. Working cavities of power cylinders are connected to distribution boxes in places injecting rubber high pressure hoses, and on rectilinear areas - metal oils.
1. Hydraulic pump NPA-64
The E-153 excavator hydraulic equipment system includes two axial-plunger pumps of the NPA-64 brand. To drive pumps on the tractor, an increases gear gearbox with a transmission of the tractor transmission is installed. The switching on the gearbox allows you to simultaneously enable or disable both pumps or turn on one pump.
The pump installed on the first stage of the gearbox has 665 rpm shaft, another pump (left) receives a drive from the second stage of the gearbox and reaches 1500 rpm. Due to the fact that knives have a different number of revolutions, their performance is not the same. The left pump takes 96 l / min; Right - 42.5 l / min. The maximum pressure on which the pump is adjusted is 70,75 kg / cm2.
The hydraulic system is refilled by the GOST 1642-50 sprinkled oil for operation at ambient air temperature + 40 ° C; At ambient air temperature from + 5 to -40 ° C, oil according to GOST 982-53 can be used and at a temperature of from - 25 to + 40 ° C - spindle 2 GOST 1707-51.
In fig. 2 shows the general NPA-64 pump device. In the case of the drive shaft on three ball bearings, a drive shaft is installed. On the right side of the drive casing body, the asymmetric body of the plunger pump is attached to bolts. The pump housing is closed and compacted with a lid. The slotted end of the drive shaft is connected to the gear coupling, and the inner end - with the flange, in which the rolling skeners of the rods. To do this, the flange has seven special bases for each ball head rod. The second ends of the rods with ball heads are roasted into plungers. Plungers have their own block of seven cylinders. The block sits on the bearing support and the spring force is tightly pressed to the polished surface of the distributor. In turn, the distributor of the cylinder block is pressed against the lid. The actuator from the actuator shaft is transmitted to the cylinder block.
Fig. 2. Pump NPA-64
The cylinder block relative to the drive shaft body is tilted at an angle of 30 °, so when the flange rotates the flanged heads of the connectors, following with the flanges, give the plungers a reciprocating movement. The progress of the plungers depends on the angle of inclination of the cylinder block. With increasing angle of inclination, the active stroke of plungers increases. In this case, the angle of inclination of the cylinder block remains constant, therefore, the plunger strokes in each cylinder will also be constant.
Works pump as follows. With the full turn of the flange of the actuator shaft, each plunger makes two strokes. The flange, and therefore, the cylinder block rotate clockwise. That plunger, which at the moment was at the bottom, will rise together with the cylinder block up. Since the flange and the cylinder block rotate in different planes, the plunger connected by the ball head roller with the flange will be pulled out of the cylinder. The piston creates a vacuum; The resulting volume of the plunger is filled with oil through the channel connected to the suction cavity of the pump. When the ball head of the rod of the plunger under consideration reaches the upper extreme position (NTC, Fig. 2), the suction stroke of the plunger under consideration ends.
The suction period takes place throughout the combination of channels with channels. When moving the ball head of the connecting rod, along the rotation of the VMT down, the plunger makes a discharge point. At the same time, the base oil - from the cylinder is squeezed through the channel into the channels of the injection line of the system.
The remaining six pump plungers make a similar work.
The oil that passed out of the working cavities of the pump through the gaps between the plungers and cylinders, is discharged into the oil tank through the drainage hole.
Sealing the pump cavity from leaks on the plane of the housing connector, between the housing and the lid, and also between the body and the flange is achieved by installing ring rubber seals. Drive shaft with flange compacted cuff.
2. Safety valves pumps
The maximum pressure in the system within 75 kg / cm2 is maintained by safety valves. Each pump has its own valve, which is installed on the pump housing.
In fig. 3 shows the left pump safety valve device. In the vertical boring of the case, a saddle is installed, which with the help of a plug is tightly pressed at the bottom of the curtain of the vertical boring. On the inner wall there is a ring outlet and a calibrated radial drilling for the passage of the injection oil from the cavity. A valve is installed in the saddle, which spring is tightly pressed against the conical seat of the saddle. The degree of spring tightening can vary by turning the adjusting bolt in the plug. The pressure from the adjusting bolt on the spring is transmitted through the rod. When the valve sits tightly in the saddle, the suction and injection cavity are separated. In this case, the oil coming from the tank through the channel will take place only to the suction cavity of the pump, and the oil injected by the pump on the channel enters the operating cavities of the power cylinders.
Fig. 3. Safety valve of the left pump
When the pressure in the injection cavity will increase and there will be more than 75 kg / cm2, the oil from the channel will be held in the ring sharing of the seat A and, overcoming the spring force, raise the valve up. Through the resulting annular gap between the valve and the seat, the excess oil will move to the suction cavity (channel 2), as a result of which the pressure in the injection chamber will decrease to the value, which is set to the valve spring 10.
The principle of operation of the safety valve of the right pump is similar to the considered case and differs on the device with a small change in the housing, which caused the corresponding change in the addition of suction and discharge highways to the pump.
To maintain the normal operation of the hydraulic excavator system, it is required at least after 100 hours of operation, and if necessary, and adjust the safety valve.
To check and perform the valve adjustment, the toolbox includes a special device, with which the adjustment is made as follows. First of all, you need to turn off both pumps, then turn the tube from the valve body and deploy a fitting instead. Through the tube and oscillation of the oscillations to attach high pressure pressure gauge into the pump injection cavity. Include pumps and one of the power cylinders. It is recommended when checking the left pump safety valve, turn on the force cylinder of the boom, and when checking the safety valve of the right cylinder, the bulldozer cylinder.
If a pressure gauge does not show a normal pressure (70-75 kg / cm2), it is necessary to adjust the pump, following the next order. Remove the seal, release the lock nut and turn the adjusting screw in the desired direction. With the undergraduated testimony of the pressure gauge, it turns the screw, with increased pressure, unscrewed. During adjustment of the safety valve, the arrow control levers or the bulldozer hold in the on no more than one minute. After adjustment, turn off the pumps, remove the adjustment device, set the plug and silent the adjusting screw.
Fig. 4. Device for adjusting the safety valve
3. Caring for NPA-64 pump
The pump works correctly if the following conditions are followed:
1. Flow the system by saved oil.
2. Set the oil pressure in the system in the range of 70-75 kg / cm2.
3. Check daily density of the compound on the planes of the pump housing connector. Oil seeping is not allowed.
4. Do not allow water during the cold season. The presence of water in the intercostal cavities of the pump body.
4. Device and operation of junction boxes
The presence in the system of two distribution boxes and two high-pressure pumps made it possible to create two independent hydraulic circuits, which have one common node - the tank of the working fluid with oil filters.
Distribution boxes are the main nodes in the hydraulic drive control mechanism; Their purpose is to direct a hydraulic stream with high pressure to the working cavities of the cylinder and at the same time removed from the opposite cavities of the cylinders who spent oil into the tank.
In the hydraulic excavator system, as noted above, two boxes are installed: the smaller size is installed on the left side along the tractor and large on the right side. The power cylinders of the bulldozer dust, the bucket and the cylinder handle are connected to the smaller box, and the power cylinders, the boom mechanism, the rotation mechanism arrows. The small and large distribution boxes differ only among themselves only the presence of a shunt spool, which is installed on a large box and has an assignment to connect the working cavities of the force cylinder of the boom among themselves and with a plum line when it is required to get the rapid downward lowering. The rest of the box on the device and work are similar to each other.
In fig. 5 shows a small junction box device.
The case of a cast-iron box, in the vertical bills of which choke with a spool is pairwise installed. Each pair of choke - the spool among themselves is rigidly linked with steel traction, which through additional thrust and levers are connected to control levers. At the inner end of the throttle, a special device is fixed, with which the vapor choke is installed in a neutral position. Such a device is called a zerostower. The device of the zerostower is simple and consists of the washers, the upper sleeve, springs, the bottom sleeves, nuts and lock nuts, screwed into the rose part of the throttle. After assembling a zerostower, it is necessary to check the stroke of the choke - the spool.
Vertical borsakers in which the seal choke pairs are covered on top with covers with centered seals, and below - covers with special sealing rings. Free spaces above the choke and spool, as well as under the chokes of spools in the process of operation, are filled with oil, leaving through the gaps between the case and the choke-choke. The upper and lower choke cavities and the spool are interconnected by means of an axial channel in the spool and special horizontal channels in the box housing. In these cavities, the oil is assigned to the drain tube into the tank. In the case of clogging the drainage tube, oil drains ceases, which is detected immediately by the appearance of spontaneous inclusion of spools.
In a small junction box, except for three pairs, the throttle - a spool, there is a speed controller, which when working one of two pairs, located on the left side of it, provides a removal of oil drain, and when the pairs are in a neutral position, it provides oil skipping . When working together with a throttle speed regulator, a smooth stroke of streaming cylinders is ensured. This will be performed if the speed controller is respectively adjusted. The speed adjustment of the speed regulator will be said somewhat later.
Fig. 5. Small Junction Box
In the third pair, the throttle is a spool, which is located on the right side of the speed regulator (in a small and large box), the choke has a slightly excellent device from chokes located on the left side of the speed controller. The specified constructive change in chokes in the third pair is due to the need to overlap the plum of the drain at the moment when the choke choke enters the operation, located after the speed regulator.
On the example of the device of a large distribution box, we will get acquainted with the features of its nodes. The direction of the oil flux in the channels of the box depends on the position of the pair choke - the spool. In the process of work, six provisions are possible.
First position. All pairs are in a neutral position. The oil supplied by the pump passes in the box along the upper channel A into the lower cavity of the speed controller B and, overcoming the resistance of the speed controller springs, lifting the spool of the regulator upwards. Through the resulting annular gap 1, the oil will go into the cavity of the C and D and on the lower channel E herself to the tank.
Second position. Left pair Throttle - a spool, located to a speed controller, raised up from a neutral position. This provision corresponds to the operation of the power cylinders of the supports. The oil comes from the pump from the channel A through the throttle of the gap will pass into the cavity to and on the channels will go into the cavity M above the spool of the speed controller, after which the spool snaps down tightly and block the drain highway. The cavity oil to the vertical channel will go to the cavity b and then on pipelines to the working cavity of the power cylinder. From another cavity of the cylinder, the oil will be supplied to the cavity of the box and through the channel E will merge into the tank.
Fig. 6a. Box Scheme (Neutral)
Fig. 6b. Power cylinders support
Fig. 6B. Power cylinders support
Fig. 6g. Running power cylinder turn
Third position. Left pair The throttle is a spool located on the left of the speed controller, lowered down from the neutral position. This position of the pair also corresponds to a specific operating mode of the power cylinders of the supports. The oil from the pump enters the channel A, then to the cavity to and through the channels to the cavity above the spool of the speed controller. The spool will close a drop of oil through cavities with and d. The injected oil from the cavity to now will not flow into the cavity b, as it was in the previous case, and in the cavity of the p. The oil from the drain cylinder will be supplied to the cavity b, and then to the channel E And in the oil tank.
Fourth position. The pairs that are on the left side (up to the speed controller) are set to a neutral position, and the steam after the speed controller is in the upper position.
In this case, the oil from the pump will go through the channel and to the cavity used under the spool of the speed controller and, lifting the spool up, according to the resulting slot 1 passes into the cavity C; Then, along the vertical channel will go into the cavity and on the oil pipeline into the working cavity of the power cylinder. From the opposite cavity of the power cylinder, the oil will be supplied to the cavity 3 and on the channel E will go to the tank.
Fifth position. A pair of choke - the spool behind the speed controller is lowered down. At the same time, the throttle, as in the previous case, blocked the drain line with the only difference that the cavity began to communicate with the injection line, and the cavity with the plum line.
Sixth position. A shunt spool is included in the operation. When lowering the spool, the oil flow from the pump passes through the box in the same way as it passed with a neutral position of steam.
In this case, the cavities of x and w are connected by oil-planes with the planes of the force cylinder of the boom, and the omitted spool, in addition, allowed these cavities to simultaneously connect to the drain line E. Thus, with the deploying spool, the arrow becomes floating and under the action of its own weight And the rude guns quickly falls.
Fig. 6d. Running power cylinder turn
Fig. 6e. Works shunting spool
5. Speed \u200b\u200bregulator
With a neutral position of couples, the choke - the spool oil goes to draining through the cavity B (Fig. 6 A). The pump at the same time does not develop high pressure, since the resistance of the oil passage is small and depends on the combination of channels, the rigidity of the springs of the regulator and the resistance of oily filters. Thus, with the neutral position of all PJSC, the throttle - the spool pump practically dries, and the spool of the speed controller is in the raised state and is balanced in a certain position of the oil pressure from the bottom from the cavity b and on top of the spring. The pressure difference between the cavity B and C is within 3 kg / cm2.
During the movement of one of the couples, the throttle is a spool from the neutral position up or down (in the working position) oil from the cavity A will take place in the cavity and through the slot to the drain into the channel E. The rest of the oil supplied by the pump will be included in the working cavity of the power cylinder And in the cavity M above the spool of the speed controller. Depending on the load on the rod of the power cylinder in the cavities M and B, accordingly, the magnitude of the oil pressure will be changed. Under the action of the force of the springs of the regulator and oil pressure, the spool of the regulator moves down and will take some new position; Moreover, the magnitude of the passage section of the slit will decrease. With a decrease in the cross section of the slit, the amount of fluid going to the drain will be reduced. Simultaneously with the change in the magnitude of the slit, the magnitude of the pressure difference between the cavity b and C, and with a change in the valve pressure, the total equilibrium position of the spool of the speed control appears. This equilibrium will come when the pressure of the springs of the spool and oil in the cavity M is equal to the pressure of the oil in the cavity of B. with a change in the load on the sink of the power cylinder, the magnitude of the oil pressure in the cassocks M and B will change, and this will in turn cause the setting of the regulator spool in New equilibrium position.
Fig. 7. Speed \u200b\u200bregulator
Since the reference surfaces of the spool of the speed controller from above and below are the same, the change in the load on the stem cylinder will not affect the magnitude of the pressure drop in the slot between the cavities B and C.
This pressure difference will depend on the springs of the springs of the spool, and this means that the speed of movement of the bayonet in the power cylinder will almost remain constant and will not depend on the load.
In order for the springer of the regulator to provide a pressure drop between cavities B and C within 3 kg / cm2, it is necessary when assembling it is set to this pressure. In factory, this adjustment is made on a special stand. Under operating conditions, checking the speed controller adjustment is carried out in the same way as recommended earlier when adjusting the safety valves using pressure gauges.
To do this, you need to do the following:
1. Install the pressure gauge to the safety valve to the pump that supplies the oil in the speed of the speed controller and notice the testimony of the pressure gauge when the pumps running.
2. Remove the speed control body control box from the housing, remove the spool and the spring, and then the housing with the adjusting screw is re-installed again in the junction box.
3. Turn on the pumps, give a normal number of speed to the engine and monitor the testimony of the pressure gauge. The first indication of the pressure gauge must be 3-3.5 kg / cm2 greater than the testimony during the second case.
In order to adjust the valve, it is necessary to tighten or lower the spool spring with the adjusting screw. After final adjustment, the screw is fixed and compacted with a nut.
6. Installing a pair of choke - spool
Initial installation of a pair of choke-spool in a neutral position is performed under the plant. During operation, the box has to be disassembled and again. As a rule, the disassembly each time is made due to the failure of seals or due to the breakage of the springs of the zerostower. Disassemble the junction boxes are permitted in a clean room by qualified mechanics. When disassembly, the removed parts fold into clean dishes filled with gasoline. After replacing the worn items, proceed to the assembly, especially paying attention to the correct formation of the choke of the choke and the spool, as this ensures the accurate installation of the choke pairs - the spool in the neutral position during the operation of the junction box.
Fig. 8. Scheme of the selection of the thickness of the puck under the throttle
The washer becomes a spool, its thickness must be no more than 0.5 mm.
If necessary, replace the washer (under the throttle) to the new one you need to know its thickness. The manufacturer recommends determining the thickness of the washer with a precision and counting as shown in Fig. 8. Such a calculation method is caused by the fact that in the process of manufacturing holes in the housing of the junction box, spools and chokes can be made some deviations in size.
After assembling the junction box, connect the pairs with control levers.
The accuracy of the assembly of the choke pair is a spool can be checked as follows: Disconnect the oil belongings from the fittings of the pair of checked. Turn on the pumps to work and smoothly move the corresponding lever of control on yourself until the oil does not appear from the hole for the lower nozzle. When an oil appears, stop the handle and make a measurement, what magnitude a spool came out from the box of the box. After that, the control lever moves from itself until oil does not seem from the hole for the upper fitting. When the oil appears, the lever stop and measure, which magnitude the spool moves down. With the correct assembly, measurements must have the same testimony. If the testimony of the strokes turned out to be unequal, it is necessary to put the puck of such a thickness under the traction so that it is equal to half the difference between the values \u200b\u200bof the stroke of the spool up and down from the fixed neutral position.
Distribution boxes for a long time work well enough if you contain them constantly clean, check the bolt connections daily, to replace the worn seals in a timely manner and systematically check and adjust the springs of the regulator. Sorry.
Without a reasonable need, the junction box is not disassembled, as it causes a premature way out of order.
Single-sided cylinders are installed on the mechanism of rotation of the column. All cylinders of the E-153 excavator are non-deliberate with the power cylinders of the time-aggregate system of tractors and have a different device from them.
Fig. 9. Cylinder arrows
The hollow cylinder rod, the rod guide surface is covered with chrome. Power cylinders of supports and dust bulldozer all-metal. From the outside end to the rod, the coupling ear is welded, and to the inner - the shank on which the cone is planted, the piston, two stops, cuffs and everything is fixed with nut. The cone when leaving the eye from the cylinder in the extreme position rests on the restrictive ring, creates a damper, resulting in a softened piston blow at the end of the rod.
The cylinder piston has a stepped shape. Cuffs are installed on both sides of the piston. A sealing ring is put in the inner ring boring of the piston, which does not allow the flow of oil along the rod from one cylinder cavity to another. The end of the shank of the rod is made on the cone, which, when entering the cover, creates a damper, mitigating the piston blow at the end of the course with the extreme left position.
Rear covers of power cylinders of the mechanism of rotation have axial and radial drills. Using these holes through a special connecting tube, touched cylinder cavities are interconnected and with an atmosphere. In order to avoid dust from entering the cylinder cavity in the connecting tube, a Sapun is installed.
The front tires in all power cylinders except the bulldozer have the same device. To pass the rod in the lid there is a hole in which the bronze sleeve is pressed for the direction of movement of the rod. Inside each lid, a sealing cuff is installed, fixed by a locking ring, and a restrictive ring. From the end of the front cover, the washer is installed, the dirtwork ^ / is tightened with a cape nut, which is fixed on the top cover of the locknut.
Due to the features of the installation of the power cylinder, the bulldozer dust on the machine, the point of attachment it from the back cover was moved to the traverse, for the installation of which a thread was made in the middle part on the pipe of the power cylinder. Traverse is so confrontated to the cylinder pipe, which is the distance from the traverse axis to the center of the hitch of the trailer rod's ear must be 395 mm. Then the traverse is fixed with lock nut.
During operation, power cylinders may be partial and complete disassembly. Full disassembly is made during repairs, and partial - when changing seals.
In the power cylinders of the E-153 excavator, three types of seals are used:
a) Merrates are installed at the outlet of the rod out of the cylinder. The assignment is to clean the chrome surface of the rod from the dirt at the time when the rod is drawn into the cylinder. This most excloses the possibility of oil pollution in the system;
b) Cuffs are installed on the piston and in the inner incision of the top cover of the cylinder. They have a prescription to create a reliable sealing of moving connections: piston with a mirror of a cylinder and rod with a bronze sleeve of the upper cover;
c) 0-shaped seals are installed in the internal ring shades of the upper and lower caps for the cylinder seal with the lids, into the inner ring sharing of the piston for sealing the stem connection with the piston.
Most often fail the first two types of seals; Less frequently - the third type of seals. Worn piston seals is found simply: the loaded rod slowly moves, and during non-working position there is a spontaneous shrinkage. This occurs as a result of the fact that oil flows from one cavity to another. The wear of the fringe is detected by abundant leaking oil between the rod and the cape. The wear of the muderpeaker leads, as a rule, to pollution of oil in the system, which is speeding the wear of precision pairs of the pump, prematurely displays a pair of junction boxes, disrupts the safety valves and speed regulators.
Disassembly and assembly of power cylinders when replacing worn seals to new should be made in a specially equipped room. All parts before assembly must be thoroughly rinsed in pure gasoline.
When assembling power cylinders, pay special attention to the safety of o-shaped seals mounted in the internal ring lid and piston. Before assembly, they need to be well fed so that it does not pinch them between the sharp edges of the annular grooves and the ends of the cylinder pipe and the rod tip.
When changing the piston, piston and rod seals, be sure to remove the top cover. Collecting cylinders, it is necessary to remember that the power cylinders of the mechanism turning the front covers of the right and left cylinders are installed unequal. At the left cylinder, the front cover is rotated relative to the rear by 75 ° clockwise and in this position is fixed with a lock nut, the front cover must be rotated relative to the rear by 75 ° counterclockwise.
8. Outcast of the hydraulic excavator system at idle
Turn off the tractor clutch clutch and turn on the oil pump mechanism. Install the motor average speed of 1100-1200 rpm and check the reliability of all seals of the hydraulic system. Check the installation of the rotation of the column and release the support. Including control levers Check the boom operation, by lifting and lowering it several times. Then, in the same way, check the operation of the power cylinders of the handle, the bucket and the mechanism of rotation of the speaker. Rotate the seat and from the second remote to check the operation of the power cylinder of the bulldozer dust.
Under normal conditions, the streams of power cylinders should be moved without jerks at uniform speed. Rotate the column to the right and left should be smooth. Control levers must be securely fixed in a neutral position. Simultaneously with the inspection of the hydraulic system nodes, check the operation of hinged joints of the excavator working bodies (bucket, bulldozer). Check the play of the conical roller bearings of the rotary speaker, if there is a need to spend adjustment. The oil temperature in the tank when running the hydraulic system should not be higher than 50 ° C.
Manager: - Hydraulic equipment of tractorsThe first hydraulic excavators appeared in the late 40s in the USA as attached to tractors, and then in England. In Germany, in the mid-50s, hydraulic equipment was used both on semi-current (attached) and full-time excavators. In the 60s, all developed countries began to produce hydraulic excavators, ousting cable cars. This is due to the essential advantage of the hydraulic drive in front of mechanical.
The main advantages of hydraulic machines in front of the rope are:
- significantly smaller masses of excavators of the same size and their dimensions;
- significantly large efforts of digging, which makes it possible to increase the sweepability of the bucket of the reverse shovel at great depth, because Dust resistance to digging is perceived by the mass of the entire excavator through the boom lift hydraulic cylinders;
- the ability to produce earthworks in cramped conditions, especially in urban environments, when using equipment with a shift in the axis of digging;
- an increase in the number of replaceable equipment, which allows to expand the technological capabilities of the excavator and reduce the volume of manual labor.
The essential advantage of hydraulic excavators are constructive and technological properties:
- hydraulic can be used as individual to each actuator, which allows component of these mechanisms without binding to the power plant, which simplifies the design of the excavator;
- in a simple way to convert the rotational movement of the mechanisms into the translational, simplifying the kinematics of the working equipment;
- stepless adjustment of speeds;
- the ability to implement large gear ratios from the energy source to working mechanisms without the use of cumbersome and sophisticated devices in the kinematics, and much more, which cannot be done in mechanical energy transmissions.
The introduction of the hydraulic drive allows you to most unify and normalize the nodes and aggregates of the hydraulic drive for machines of different sizes, limiting their nomenclature and increase production seriality. It also leads to a reduction in spare parts in the workshop warehouses, reducing the cost of their acquisition and storage. In addition, the use of hydraulic drive allows the use of an aggregate excavator repair method, reducing downtime and increasing the useful time of the machine.
In the USSR, the first hydraulic excavators began to be released in 1955, the production of which was immediately organized in large volumes.
Fig. 1 E-153 Bulldozer Excavator
This is mounted on the basis of the MTZ tractor hydraulic excavator E-151 with a tank of 0.15 m 3. As a hydraulic plant, gear pumps NSH and hydraulic distributors R-75 were used. Then, E-153 excavators began to be produced at the replacement of E-151, (Fig. 1), and later EO-2621 with a bucket of 0.25 m 3. Plants were specialized on the release of these excavators: the Kiev "Red Excavator", Zlatoust Machine-Building, Ceranian Excavator, Borodyansky Excavator. However, the lack of hydraulic equipment with high parameters, both in terms of performance and for working pressure, washed back to the creation of domestic full-air excavators.
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Fig. 2 E-5015 excavator
In 1962, an international exhibition of construction and road vehicles took place in Moscow. At this exhibition, the English firm demonstrated a tracked excavator with a bucket of 0.5 m3. This machine impressed with its productivity, maneuverability, ease of control. This car was purchased, and it was decided to reproduce it at the Kyiv Plant "Red Excavator", which began to produce it under the E-5015 index, having mastered the production of hydraulic equipment. (Fig.2)
In the early 60s of the last century, the group of enthusiasts-supporters of hydraulic excavators was organized: Berkman I.L., Bulanov A.A., Morgachev I.I. et al. A technical proposal was developed for the creation of excavators and cranks with hydraulic drive, only 16 cars on a tracked and special pneumocole chassis. The opponent was the edges of A.S., proving that it is impossible to experiment on consumers. Technical proposal is considered from the Deputy Minister of Construction and Road Engineering Gropy N.K. Rapporteur Morgachev I.I., as a leading designer of this range of cars. Grechin N.K. Approves the technical proposal and the department of single-loving excavators and jerk self-propelled cranes (OEK) VNISTROYDORMASH proceeds to the development of technical tasks for design and technical projects. TsNIIIOMTP Gosstroy the USSR, as the chief representative of the customer, coordinates the technical tasks for the design of these machines.
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Fig. 3 NSh Series Pump
In the industry at that time there was no base for hydraulic machines. What could be calculated by the designers? These are the gear pumps of the NSH-10, NSH-32 and NSh-46 (Fig. 3) by the working volume, respectively, 10, 32 and 46 cm 3 / respectively and the working pressure of up to 100 MPa, axial-plunger pumps of the NPA-64 motors (Fig. 4) Working volume 64 cm 3 / O and working pressure 70 MPa and IIM-5 working volume 71 cm 3 / O and working pressure up to 150 kgf / cm2, high-generable axial-piston hydraulic motors WGD-420 and WGD-630 for torque 420 and 630 kgm, respectively.
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Fig. 4 NPA-64 Motor Pump
In the mid-60s, Grechin N.K. Procurement from the company "K. Ruh" (Germany) licenses for production in the USSR of hydraulic equipment: axial-plunger adjustable pumps of type 207.20, 207.25 and 207.32 with a maximum working volume of 54.8, 107, and 225 cm 3 / on and short-term pressure to 250 kgf / cm2, twined axial-piston adjustable pumps of type 223.20 and 223.25 with a maximum working volume of 54,8 + 54.8 and 107 + 107 cm 3 / about and short-term pressure up to 250 kgf / cm2, respectively, axial-piston irregular pumps and hydraulic motors Type 210.12, 210.16, 210.20, 210.25 and 210.32 Working volume 11.6, 28.1, 54.8, 107 and 225 s m 3 / on and short-term pressure up to 250 kgf / cm2, respectively, commissioning equipment (hydraulic distributors, limiters Power, regulators, etc.). Machinery equipment is also purchased for the production of this hydraulic equipment, the truth is not in the complete required volume and nomenclature.
Source photo: Tehnoniki.ru
At the same time, the Minneftekhimprom of the USSR of the development and production of hydraulic oils of the type VMGZ with the necessary viscosity at various ambient temperatures is carried out. In Japan, a metal mesh with 25 microns for filters is purchased. Then Rosnefsesnab organizes the production of paper filters "Regotmaas" with the subtlety of cleaning up to 10 microns.
The construction, road and communal engineering industries produce specialization of plants for the production of hydraulic equipment. To do this, it was necessary to reconstruct and technical re-equipment of workshops and sections of factories, partially their expansion, create a new production of machining, casting forging and antifriction cast iron, steel, chill casting, galvanic coating, etc. In the shortest possible time it was necessary to prepare tens of thousands of workers and engineering and technical workers of new specialties. And most importantly, it was necessary to reverse the old psychology of people. And this is all with the residual principle of financing.
The first Deputy Minister of Construction, Road and Municipal Machinery Rostotsky V.K. was played an exceptional role in re-equipment of factories and their specialization, which was supported by Ginchi N.K. In the introduction of hydraulic machines in the production. But Opponents Grekin N.K. There was a serious trump card: and where to take the machinists and mechanics and operational mechanics of hydraulic machines?
Groups of new specialties were organized in PTU, manufacturers of machines are carried out training for excavators, repairmen, etc. Publishing House "Higher School" ordered textbooks on these machines. Employees of VNISTROYDORMASH, who wrote a large number of teaching aids on this subject were provided to great help. Thus, Excavator plants Kovrovsky, Tverskaya (Kalininsky), Voronezh transfers to the release of more advanced machines with hydraulic drive, instead of mechanical with cable control.
