278 results about "Double acting" patented technology

The invention belongs to the field of electro-hydraulic actuators, and particularly relates to a double-cylinder double-acting rotary electro-hydraulic actuator which comprises a box body, a sealing cover provided with a shaft hole is installed at the front end of the box body, a bearing installed in an inner cavity of the box body is arranged behind the sealing cover, and a gear shaft penetrates through the middle of the bearing. The gear shaft is sleeved with a gear. When the gear shaft is driven, the upper oil cylinder and the lower oil cylinder move oppositely, the pistons on the upper portion and the lower portion drive the racks to be meshed with the gears through jacking, stretching and resetting, and the four cylinders are crossed and symmetrical, so that the gear shaft is evenly pushed by the two oil cylinders all the time in the rotating process, operation is very stable, torque output of the gear shaft is increased in a limited space, and the service life of the gear shaft is prolonged. And the double-acting design enables the opening and closing actions to be actively driven by hydraulic pressure, the control response is fast, the position is accurate, and the hydraulic valve is suitable for opening and closing of large-torque valves of ships, chemical engineering and the like.

A cylinder is a double-acting single-rod cylinder, one end of the cylinder is a cylinder rodless cavity, the other end of the cylinder is a cylinder rod cavity, and a cylinder body of the cylinder is sequentially provided with sensors I, II and III for detecting the position of a piston or a piston rod; high-speed operation is carried out in sensor I and II regions, and low-speed operation is carried out in other regions; a rodless cavity of the air cylinder is communicated with an OR valve I, and the OR valve I is connected with two-position three-way reversing valves I and II in parallel; a rod cavity of the air cylinder is communicated with an OR valve II, and the OR valve II is connected with two-position three-way reversing valves III and IV in parallel; the two-position three-way reversing valves I and III are connected in parallel, then connected in series with a low-speed pressure reducing valve 1 and connected with an air source; the two-position three-way reversing valves II and IV are connected in parallel, then connected in series with a high-speed pressure reducing valve and connected with an air source; the low-speed pressure-reducing valve and the high-speed pressure-reducing valve are The device is fast in opening and closing, stable in starting, low in cost, good in effect, safe to operate, simple to debug, capable of avoiding door flying, capable of improving installation efficiency and suitable for popularization.

The invention relates to an automatic screw nut ball assembling device and a pneumatic ball feeding method. Comprising a fixed seat, a material pushing assembly arranged on the fixed seat, a vibration disc arranged above the material pushing assembly and used for conveying balls, a controller electrically connected with the material pushing assembly and the vibration disc, and a ball filling assembly arranged on the fixed seat and located in front of the material pushing assembly. Wherein the pushing assembly comprises a first lifting frame installed on the fixing base, a ball guide rail body arranged on the front side of the first lifting frame and a stop dog connected with the lower portion of the ball guide rail body, and the ball filling assembly comprises a positioning sleeve connected with the stop dog. The controller integrally controls execution components such as the vibration disc, the pushing air cylinder and the double-acting air cylinder, full-process automation from ball conveying, number limiting, ball falling and guiding to pneumatic ball blowing is achieved, continuous cycle operation can be completed through one-key starting only by manual feeding and discharging, the assembly efficiency is improved, and the automatic ball feeding and discharging device can be easily integrated with an automatic production line.

The application discloses a silicon steel sheet laminating and pressing equipment based on self-control pressure and relates to the technical field of silicon steel sheet manufacturing equipment. The equipment comprises a C-shaped frame, a pressure conduction block and a double-acting hydraulic cylinder. A cross-shaped oil guide groove is milled at the bottom end of the outer wall of the pressure conduction block. Two rows of needle roller bearings are symmetrically installed on the side surface of the outer wall of the pressure conduction block. A laminating pressing plate is fixedly installed at the bottom end of the outer wall of the pressure conduction block. An annular oil cavity is formed at the top end of the outer wall of the laminating pressing plate. The annular oil cavity is communicated with the oil guide groove. A pressure sensing film is fixedly installed at the bottom end of the outer wall of the laminating pressing plate. A strain grid is etched at the rear end of the outer wall of the pressure sensing film. The strain grid etched at the pressure sensing film can sense the pressing pressure, the real-time detection and automatic closed-loop adjustment of the pressing pressure are realized, the problem that the pressure fluctuation of the pressing equipment is large and the laminates are deformed due to overpressure or loose due to insufficient pressure caused by the adjustment depending on manual experience is solved, and the compactness, flatness and core performance consistency of the laminates are improved.

The utility model relates to the technical field of pipeline valves, in particular to a device for controlling slow closing of a check valve, the check valve and a brake, a shell of the brake can axially rotate on a base of the brake, and the brake drives a brake assembly through an internal brake piston to generate friction braking with the shell of the brake; a piston rod of the double-acting piston cylinder is fixedly connected with a shell of the brake through the overturning assembly. The brake fluid storage tank is in one-way communication with a fluid inlet cavity of the double-acting piston cylinder and the brake piston through a first pipeline, the brake fluid storage tank is in two-way communication with the fluid inlet cavity of the double-acting piston cylinder and the brake piston through a second pipeline, and a control valve is arranged on the second pipeline. The brake fluid storage tank is bidirectionally communicated with the fluid return cavity through a third pipeline; friction braking is generated through the braking assembly and the brake shell, the slow closing effect of the valve clack is achieved, the slow closing effect is stable, the water hammer effect is remarkably eliminated, and when a water pump is started, the valve clack of the check valve can be easily and normally opened.

The utility model discloses a rotary temperature measuring structure, which comprises a main mounting plate, the top of the main mounting plate is fixedly connected with a protective cover, the top of the main mounting plate is provided with a telescoping mechanism, a rotating mechanism and a temperature measuring mechanism, the telescoping mechanism comprises a threaded cylinder and a cylinder mounting seat, the threaded cylinder is mounted on the cylinder mounting seat, and the rotating mechanism is mounted on the cylinder mounting seat. And the rotating mechanism is used for realizing the telescopic action of the temperature measuring probe and comprises a pen-shaped cylinder, a guide rail pair, a gear rack, a rotating base, a deep groove ball bearing and a driving arm, the pen-shaped cylinder is fixedly connected with the main mounting plate, and the front end of the pen-shaped cylinder is connected with the guide rail connecting plate. According to the utility model, the double-acting threaded cylinder is used as a telescoping power source, the piston linearly moves to push the temperature measuring probe to telescope, and the pen-shaped cylinder is matched with the gear and the rack for transmission to drive the gear to rotate, so that the temperature measuring probe can rotate, the temperature measuring requirements of different positions in a narrow space are met, and the problem of insufficient flexibility of a traditional temperature measuring mechanism is solved.

The utility model relates to the technical field of mine transportation equipment, in particular to a tail telescopic device of a belt conveyor, which comprises a driving unit, a guide mechanism, a movable tail and an intelligent control system, the driving unit adopts a double-acting hydraulic cylinder and hydraulic station closed oil way design, and the position of a piston rod is locked through a hydraulic lock; the guide mechanism comprises a first guide rail and a second guide rail, and the movable tail is mounted on the first guide rail, so that linear movement of the tail is ensured; a movable carrier roller frame is installed on the second guide rail, and the movable machine tail is connected with the movable carrier roller frame through a round-link chain. According to the device, the tensioning trolley and the carrier roller frame move along the first guide rail and the second guide rail respectively through independent guidance of the double guide rails, mutual interference is avoided, rigid impact is further reduced through flexible connection of the round-link chain, the device adapts to unevenness of the bottom face of a roadway, real-time linkage of the PLC and the tensioning trolley is achieved through intelligent cooperative control, and the response speed of the system is increased.

The utility model discloses a deicing compression structure for snow sweeper. The utility model, including the support: the middle position of one side of support is provided with snow throwing cylinder, the middle position of the other side of support is provided with the protective cover, the top of both ends of support all rotatory mounting has the hydraulic cylinder, the bottom rotatory of other side of support is provided with the movable frame, one end of support and movable frame is provided with transmission structure, the top of support is provided with the drive motor, the other side rotatory of inside of support is provided with the snow roller. The utility model discloses, is provided with deicing compression structure, if need to clean the hard ice on the road, through the double -acting hydraulic cylinder drive first connecting rod and second connecting rod remove, make the support rod can move along with it, drive the ice breaking roller to go up and down, the ice breaking roller closely ground, in the ice breaking roller moving process, through the auxiliary of buffer, make broken roll can break the hard ice on the road, finally by the snow roller will be broken ice and clean up.

The utility model belongs to the technical field of land levelers, and discloses a steering structure and a land leveler. The steering structure comprises a bridge frame, two steering knuckles, a double-acting oil cylinder and a sliding connection assembly. The two steering knuckles are rotationally arranged at the two ends of the bridge frame in the first direction; the double-acting oil cylinder comprises a piston rod and an oil cylinder body arranged on the piston rod in a sliding mode, and the piston rod is fixedly arranged on the bridge frame and extends in the first direction. The sliding connection assembly comprises a sliding connection body and two steering pull rods, the sliding connection body is fixedly connected with the oil cylinder body, meanwhile, the sliding connection body is in sliding connection with the bridge frame in the first direction, and the two ends of the sliding connection body in the first direction are hinged to one ends of the two steering pull rods correspondingly; the ends, away from the sliding connecting body, of the two steering pull rods are hinged to the two steering knuckles correspondingly. According to the steering structure, the sliding connector can limit the oil cylinder body to rotate around the axis of the piston rod, abrasion of the double-acting oil cylinder is reduced, and the service life of the double-acting oil cylinder is prolonged.

1. The name of the design product: double cylinder double action hydraulic hose diaphragm pump. 2. The use of the design product: the design is a double cylinder double action hydraulic hose diaphragm pump using compressed air or liquid as power source. 3. The design points of the design product: in shape. 4. The picture or photo that best indicates the design points: perspective view.

The utility model discloses a double-acting sealing ring for a shaft, which belongs to the technical field of sealing and comprises a ring-shaped body deformed by extrusion, the ring-shaped body consists of a first sealing ring part and a second sealing ring part, the first sealing ring part is axially arranged and faces a high-pressure medium, and the second sealing ring part is opposite to the high-pressure medium. An annular groove is formed in the annular surface, facing a high-pressure medium, of the first sealing ring part, and convex parts extruded by a mounting structure are formed on the outer circumferential surface and the inner circumferential surface of the second sealing ring part. The sealing ring for the double-acting sealing shaft overcomes the problems that a traditional sealing ring is prone to abrasion, limited in sealing performance, complex in maintenance and the like, has the advantages of being good in sealing reliability, low in friction characteristic, high in pressure self-sealing capacity and convenient to install and maintain, and can provide a more durable and stable sealing effect under various working conditions.

The invention relates to a cartridge-type electromagnetically actuated double-acting reciprocating piston pump (1), the reciprocating piston pump (1) having a pump axis (10), a pump inlet (5), and a pump outlet (6) and comprising the following: a mounting system (31) which accommodates two coil assemblies (25) of the same design in a stationary manner opposite one another in the axial direction, the first coil assembly (25') having a first annular coil (12') and a first fixed armature (13'), and the second coil assembly (25'') having a second annular coil (12'') and a second fixed armature (13''); a pump piston (19) which integrates the function of an armature and of a delivery piston and is mounted for movement along the pump axis (10) and is arranged radially inside coaxially to the first and second coil assemblies (25', 25''); a first and a second displacement chamber (24', 24''), the volume of which changes when the pump piston (19) in the form of an armature is moved under the effect of the coil assemblies (25); two inlet valves of the same design, specifically a first inlet valve (20') and a second inlet valve (20''); two outlet valves of the same design, specifically a first outlet valve (21') and a second outlet valve (21'').

Damping arrangement (10) of an active suspension for an axle of a motor vehicle, wherein a damping system (10a, 10b) interacts with each wheel of the axle, wherein each of the damping systems (10a, 10b) comprises the following assemblies: a damper (11) comprising a double-acting hydraulic cylinder (12) and a piston (13), wherein the damper (11) can be coupled to a wheel suspension system of the respective wheel, a hydraulic pump (16) and an electric motor (17) for driving the respective hydraulic pump (16), wherein the hydraulic pump (16) can be driven in different directions of rotation by the electric motor (17) to provide different delivery directions, a hydraulic unit (19) comprising a hydraulic reservoir (20) and valves (21, 22, 23, 24), wherein the hydraulic pump (16) and the hydraulic unit (19) of the respective damping system (10a, 10b) interact with hydraulic chambers (14, 15) of the hydraulic cylinder (12) of the respective damping system (10a, 10b) in such a way that, depending on the delivery direction of the hydraulic pump (16) of the hydraulic unit (19), a movement of the piston (13) in a first actuation direction or in a second actuation direction can be provided, wherein the hydraulic pumps (16) and the electric motors (17) of both damping systems (10a, 10b) are combined to form a motor-pump unit (28), characterized in that The motor-pump unit (28) is attached to an axle carrier (41) of the axle on both sides of the same by at least two bearings (29) each, which are each received in a common bearing support (30), wherein a first bearing support (30) is integrated into a first housing cover (31) of a housing (32) of the motor-pump unit (28), and wherein a second bearing support (30) is connected to a second housing cover (35) of the housing (32) of the motor-pump unit (28) via a tie rod (33) and a bearing tube (34).

The utility model belongs to the technical field of hydraulic push rods, and discloses a hydraulic oil bag driven double-acting electric hydraulic push rod mechanism which comprises a valve seat, a motor is installed on the valve seat, a plurality of valve holes are formed in the valve seat, and each valve hole is correspondingly communicated with a one-way valve, a manual pressure release valve, an exhaust hole, an overflow valve, an upper branch pipe and a lower branch pipe. The output end of the motor is connected with a hydraulic pump, the hydraulic pump is provided with a plurality of via holes corresponding to the valve holes in position, and the valve seat is provided with an oil bag and an oil tank. According to the double-acting hydraulic oil tank, the double-acting design is adopted, balanced pushing force and pulling force can be provided in different directions, the double-acting hydraulic oil tank is suitable for more application scenes, due to the innovative oil bag design, the oil tank is more compact, the total weight is reduced, and the durability and flexibility of the whole system are improved. The oil bag is made of a high-strength elastic material, hydraulic fluctuation can be effectively absorbed, and fluid stability is ensured.

To provide an actuator assembly involving three chambers for a heavy machine such as a drilling machine in order to reduce restriction loss in a control valve.SOLUTION: An actuator assembly 1000 includes a main cylinder assembly 1100 and a plunger cylinder assembly 1200 disposed in parallel with the main cylinder assembly. The main cylinder assembly is a double-acting type cylinder assembly, and the plunger cylinder assembly is a single-acting type cylinder assembly. The actuator assembly includes three chambers 1102A, 1102B, 1202A applied to be selectively coupled to at least one of a high pressure hydraulic pressure line, an intermediate pressure hydraulic pressure line and a low pressure hydraulic pressure line on the basis of a load requirement of the actuator assembly. The actuator assembly reduces restriction loss in a control valve and thus reduces entire power consumption of a heavy machine.SELECTED DRAWING: Figure 1A

The invention discloses a crank, a shaking table driving device comprising the crank and a shaking table comprising the driving device.The driving device comprises a box body, a belt wheel, the crank and a connecting rod mechanism, the crank is provided with connecting shafts with different axial directions, and the connecting rod mechanism on the two sides of the crank and a table body can be driven to move at the same time through the crank connecting rod mechanism. A spring arranged for counteracting asymmetric impact force in the prior art is overcome, the counter-acting force of the bed body on the crank is fully utilized, a certain driving force is provided for the crank in turn, and the crank is promoted to rotate. Therefore, the double-acting output type design is adopted, the effects of power compensation and stored energy release are achieved, and the energy-saving effect is good.

An internal combustion engine includes a cylinder head with an exhaust manifold configured to supply exhaust gas through a main exhaust outlet to a main exhaust aftertreatment system having a main catalytic converter, a bypass passage in fluid communication with the exhaust manifold via a bypass port, a bypass catalytic converter disposed within the bypass passage, and a dual-acting valve assembly configured to move between a first position that seals the bypass port, and a second position that seals the main exhaust outlet. During cold start, long idle, and / or low main catalytic converter temperature conditions, the dual-active valve assembly is moved to the second position to direct exhaust flow through the bypass passage and the bypass catalytic converter to reduce emissions.

A device for conveying viscous material to an applicator has a conveying cylinder in which a double-acting conveying piston is movable to and fro. The conveying cylinder has first and second chambers separated from one another by the conveying piston. Each chamber has a material inlet and outlet. A conveying device is connected to the material inlets for the pressurized introduction of viscous material into the conveying cylinder chambers, and a valve device closes and opens the material inlets and outlets. In a first switching position, the valve device opens the first chamber material inlet and the second chamber material outlet and closes the second chamber material inlet and the first chamber material outlet and, in a second switching position, releases the second chamber material inlet and the first chamber material outlet and closes the first chamber material inlet and the second chamber material outlet.

The present application relates to deep-sea pressure maintaining sampling technical field, disclose a kind of whole sea depth macroorganism active pressure maintaining sampling system and method, system includes sampling cylinder main body structure and active pressure compensation structure;Active pressure compensation structure includes: drive mechanism, reciprocating booster unit includes double-acting booster cylinder, variable diameter piston is arranged in booster cylinder, the diameter of high-pressure end of variable diameter piston is less than the diameter of low-pressure end, the inside of cylinder is divided into high-pressure chamber, low-pressure chamber and liquid exchange chamber, low-pressure chamber is communicated with sampling cylinder main body structure by a high-pressure water injection path, high-pressure chamber is also communicated with the outlet of liquid injection micropump by a water supplement pipeline, each control port of hydraulic control reversing valve is communicated with the outlet of liquid injection micropump, low-pressure chamber, liquid exchange chamber and high-pressure chamber by hydraulic pipeline one-to-one correspondence, compensator is communicated with the oil inlet of liquid injection micropump, liquid exchange chamber and the oil return port of hydraulic control reversing valve, realize single power source, infinite stroke's continuous, accurate pressure compensation, especially suitable for whole sea depth, large capacity macroorganism pressure maintaining sampling.

The application relates to the technical field of diaphragm pumps and discloses a double-acting hydraulic four-fluorine diaphragm pump which comprises a pump body, a piston and two delivery units, the pump body is internally provided with a piston rod channel and a piston cylinder for reciprocating movement of the piston, the two delivery units are symmetrically arranged along the piston cylinder axis, the two delivery units share one pump body, each delivery unit comprises a pump cover, a double-layer diaphragm is arranged between the pump cover and the pump body, the double-layer diaphragm forms a diaphragm chamber and a hydraulic chamber with the pump cover and the pump body, pressure taking devices for pressure alarm are arranged at the two ends of the double-layer diaphragm, the pump body is internally provided with an oil channel which is in communication with the piston cylinder, the pump body is provided with a mounting hole for mounting a limiting valve, and the limiting valve is located between the hydraulic chamber and the oil channel; the oil channel inlets of the two delivery units are respectively located above the left side and below the right side of the piston cylinder, and the piston seat of the piston reciprocates between the two inlets. In actual use, the double-acting hydraulic four-fluorine diaphragm pump has compact structure, and the volume and weight are only slightly increased compared with those of a single-acting hydraulic four-fluorine diaphragm pump, but the delivery flow of the pump is about twice that of the single-acting hydraulic four-fluorine diaphragm pump.

Fitting assembly (3) for an adjustment device of motor vehicles with a double-acting drive unit, comprising a drive housing (4) and a drive lever pivotable about an axis for generating a rotary movement of a drive element, the direction of rotation of which, starting from a zero point position resettable by means of a return spring (6), depends on the pivoting direction of the drive lever, without reversing an output element during the reversing movement of the drive lever, and a locking brake device connected to the drive element, which releases a drive-side torque to the output element connected to the adjustment device and provided on a side part (2) of the adjustment device, blocks a drive-side torque and has a brake housing (5) connected to the drive housing (4) and arranged coaxially to the drive axis, characterized by an alignment element (40) connected to the fitting assembly (3), which can be positively connected to a positive locking element (25) arranged on the side part (2) in such a way that the alignment of the fitting assembly (3) to the side part (2) is determined, wherein the brake housing (5) of the parking brake device is designed as a brake pot, from which several webs or a circumferential ring flange (50) project laterally, and The drive housing (4) has several distributed mounting bosses (41, 42, 43) around its circumference for receiving fastening means (91, 92, 93) for connecting the fitting assembly (3) to the side part (2), and the length of the mounting bosses (41, 42, 43) oriented towards the side part (2) is dimensioned such that when the fitting assembly (3) is connected to the side part (2) with the bottom (500) of the brake housing (5) in contact with the surface of the side part (2), the drive housing (4) is deformed to force-fit connection of the brake housing (5) to the side part (2).

1. Name of the designed product: Double layer dust valve (reducer form). 2. Use of the designed product: For controlling and discharging dust or particulate matter storage and unloading. 3. Design points of the designed product: In shape. 4. Picture or photo that best shows the design points: Fig. 1.

The utility model relates to a hydraulic technology field, concretely relates to a kind of hydraulic system and hydraulic device.A kind of hydraulic system, for the single double-acting switching of lifting cylinder, comprising: big cavity oil circuit, including big cavity oil inlet oil circuit and big cavity oil return oil circuit, all with the big cavity of lifting cylinder intercommunication, the lifting valve of control on-off is arranged on the big cavity oil inlet oil circuit, the down valve of control on-off is arranged on the big cavity oil return oil circuit;Small cavity oil circuit, with the small cavity of lifting cylinder intercommunication;Switching valve, control the oil inlet of big cavity oil inlet oil circuit and the oil inlet and outlet of small cavity oil circuit;Unloading oil circuit, in parallel in big cavity oil inlet oil circuit, unloading valve is arranged on the unloading oil circuit, the unloading valve is opened and closed under the pressure of oil inlet and outlet pressure of lifting valve.Solved the technical problem that hydraulic system in prior art cannot have single double-acting, poor applicability.

The utility model provides a hydraulic system of a broken line type multi-cutter shearing machine guide rail automatic adjusting and compensating device. An adjusting base double-output-shaft double-acting oil cylinder is hinged to an adjusting base through a bolt. A movable guide rail double-output-shaft double-acting oil cylinder is hinged to the movable guide rail through a bolt. A fixed seat double-output-shaft double-acting oil cylinder is hinged to the fixed seat through a bolt; the adjusting seat double-output-shaft double-acting oil cylinder, the movable guide rail double-output-shaft double-acting oil cylinder and the fixed seat double-output-shaft double-acting oil cylinder are respectively connected with an energy accumulator and a control valve group; a pressure sensor is mounted on the energy accumulator and the control valve group; the adjusting base double-output-shaft double-acting oil cylinder, the movable guide rail double-output-shaft double-acting oil cylinder and the fixed base double-output-shaft double-acting oil cylinder are connected with the two-way hydraulic control one-way valve set and the reversing control valve set respectively. Through interaction of all hydraulic elements, the adjusting oil cylinder is driven to conduct compensation adjustment on the guide rail gap in real time.

The utility model discloses a booster pump, and relates to the technical field of gas pressurization. The booster pump comprises a driving cylinder body, a piston rod, a first driving piston, a second driving piston, a first booster cylinder body and a second booster cylinder body, the driving cylinder body is provided with a first driving cavity and a second driving cavity which are symmetrically arranged; the piston rod penetrates through the partition wall, and the two ends of the piston rod extend into the first driving cavity and the second driving cavity correspondingly. The first pressurizing cylinder body is connected with one end of the driving cylinder body, and a first pressurizing piston connected with the first driving piston is arranged in the first pressurizing cavity; the second pressurizing cylinder body is connected with the other end of the driving cylinder body, and a second pressurizing piston connected with the second driving piston is arranged in the second pressurizing cavity. The structure of the booster pump is improved, and the single-pole double-acting double-drive booster pump is high in strength, good in sealing performance, reasonable in structure, suitable for low-temperature and high-pressure environments and particularly suitable for boosting liquid carbon dioxide.

According to the closed type hydraulic oil cylinder system driven by the motor, in the action process of the oil cylinder, the oil sucking and discharging amount of the hydraulic pump / motor is equal, additional hydraulic oil supplementing is not needed, the motor can output torque or control the rotating speed, the hydraulic pump / motor is driven, and the oil cylinder executes actions according to the needed direction and speed. The closed hydraulic oil cylinder system comprises an oil cylinder a and an oil cylinder b, and the oil cylinder a and the oil cylinder b are both double-acting piston type oil cylinders with rod cavities and rodless cavities. When the moving distance of the piston rod of the oil cylinder a is equal to that of the piston rod of the oil cylinder b, the displacement difference of the oil cylinder a is equal to that of the oil cylinder b, a rod cavity of the oil cylinder a is communicated with a rodless cavity of the oil cylinder b and is communicated with a first liquid inlet / outlet of the hydraulic pump / motor, and the rodless cavity of the oil cylinder a is communicated with a rod cavity of the oil cylinder b and is communicated with a second liquid inlet / outlet of the hydraulic pump / motor. The first liquid inlet / outlet is communicated with a second liquid inlet / outlet of the hydraulic pump / motor; the motor drives the hydraulic pump / motor; the controller controls the motor output torque and the motor rotating speed.