Bidirectional servo electro-hydraulic pump device and control method thereof

Abstract

The invention discloses a two-way servo electro-hydraulic pump device and a control method thereof, and belongs to the technical field of servo electro-hydraulic pump devices.The two-way servo electro-hydraulic pump device comprises a driving mechanism and a pump shell, a closed multifunctional cavity is formed in the pump shell, and the multifunctional cavity is provided with a two-way oil pump assembly; meanwhile, the cavity serves as a working oil storage cavity, a leaked oil recovery cavity and an oil suction cavity of the pump; in the pump shell and / or the hole channel connecting piece connected with the pump shell in a fastening mode, through holes and / or the combination of the through holes and the valve pieces form a built-in oil way. The multifunctional cavity is formed in the pump shell, the built-in oil way is arranged in the pump shell and used for communicating the multifunctional cavity, the inlet and outlet of the two-way oil pump assembly and the hydraulic executing mechanism, the main oil way is formed in the pump shell and / or the body of the hole channel connecting piece, external pipelines and independent valve blocks can be reduced, the connecting length and the number of sealing interfaces are reduced, and the service life is prolonged. Therefore, the leakage risk and the assembly complexity are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electro-hydraulic pump, in particular to a servo bidirectional servo electro-hydraulic pump device and a control method thereof. BACKGROUND

[0002] The existing servo electro-hydraulic system is usually driven by a servo motor to drive a hydraulic pump, and is connected with a hydraulic actuator through an external oil tank, a valve block and a pipeline. This structure has the following disadvantages: There are many external pipelines and complex connections, the system is prone to leakage, and maintenance is difficult; The oil pump is separated from the oil tank, the oil suction path is long, and cavitation is prone to occur under low-speed working conditions, affecting the stability and response speed of the pump; Most of the functional valves are installed externally, and the overall integration is low, resulting in a large equipment size; The system has poor adaptability and is difficult to apply to space-limited or highly integrated occasions.

[0003] Although there are improved schemes of integrating the motor and the pump shell, and attempts have been made to set part of the oil circuit in the pump shell, but it still cannot realize the storage of oil, the recovery of leaked oil, the oil suction function and the integration of valves in the pump shell. The existing integrated pump group can directly couple the motor and the pump body, but still needs an external oil tank and a valve block, and cannot complete the full circulation of oil in the pump shell. This leads to pressure fluctuations and response delays in the system during low-speed start-up and micro-motion control, making it difficult to achieve high-precision servo control.

[0004] Therefore, how to provide a bidirectional servo electro-hydraulic pump device with compact structure, high functional integration, flexible installation and excellent performance has become a technical problem to be solved in the field. SUMMARY

[0005] The purpose of the present application is to provide a bidirectional servo electro-hydraulic pump device, which forms a multifunctional chamber inside the pump shell, and integrates the necessary oil circuit and valve on the shell, thereby reducing the external pipeline, improving the integration and reliability of the system, improving the oil suction performance and servo response accuracy of the pump, and at the same time having the ability to expand the external auxiliary oil tank and flexible split installation.

[0006] To achieve the above purpose, the present application provides a bidirectional servo electro-hydraulic pump device, comprising: A pump shell: a closed multifunctional chamber is formed inside, used to accommodate a bidirectional oil pump assembly, and simultaneously as a working oil storage chamber, a leaked oil recovery chamber and an oil suction chamber of the pump; An internal oil circuit: the pump shell and or a hole connection member fastened thereto are provided with a valve and a hole penetrating through, connecting the multifunctional chamber, the oil suction port of the bidirectional oil pump assembly and the external actuator; Integrated structure: the pump housing is directly connected as the direct bearing of the driving mechanism and the actuator, and can be directly connected with the hydraulic cylinder or the hydraulic motor, and can also be installed separately through a short pipeline when necessary.

[0007] The preferred scheme includes: The bidirectional oil pump assembly is a plunger pump assembly; mainly including a pump shaft, an inclined disc, a plunger cylinder, a plunger, and a flow distribution disc, the flow distribution disc forms two independent flow distribution channels with the pump housing, and is connected with the multifunctional chamber through a one-way valve and communicated with the actuator chamber, and realizes bidirectional alternating oil suction and oil discharge under the forward and reverse rotation driving of the pump assembly.

[0008] The pump housing directly bears the motor and the actuator, forming an integrated installation structure; The pump housing is provided with an external interface, which can be connected with an external oil storage tank or an external auxiliary oil tank in the case of insufficient oil or special working conditions; the oil storage tank can be a normal pressure tank body connected with the external atmosphere or a sealed pressure tank body.

[0009] The controller of the driving mechanism and the sensor installed on the actuator, such as a displacement sensor, a pressure sensor, a rotary encoder or a torque sensor, constitute a closed-loop control system to realize high-precision servo adjustment.

[0010] Compared with the prior art, the present application has the following advantages: 1. High integration, reduced leakage path The pump housing forms a multifunctional chamber and is provided with an internal oil circuit for connecting the multifunctional chamber, the inlet and outlet of the bidirectional oil pump assembly and the hydraulic actuator, and the main oil circuit is formed in the body of the pump housing and / or the channel connector, which is beneficial to reduce the external pipeline, independent valve block, connection length and sealing interface number, thereby reducing the leakage risk and assembly complexity.

[0011] 2. Internalization of oil circuit and valve, shortening of control link The oil circuit channel is formed in the inner wall of the pump housing and / or the channel connector, and at least the functional valve including the one-way valve, the oil overflow valve or the like is directly integrated in the channel, thereby constituting the main oil passage, the oil suction passage and the oil overflow passage. Compared with the scheme of using external valve block and connecting pipe, the layout significantly shortens the oil circuit, reduces the elastic change caused by the volume of oil and the hose, and is beneficial to improve the control accuracy of the system.

[0012] 3. Multifunctional chamber direct suction improves low-speed stability The oil suction port of the bidirectional oil pump assembly is communicated with the multifunctional chamber, the oil suction path is significantly shortened, which is beneficial to reduce the suction inlet pressure drop and the cavitation tendency, improve the oil suction stability and repeat accuracy under low-speed / micro-motion working conditions, and improve the dynamic response.

[0013] 4. Optimization of component quantity and volume, reduction of energy efficiency By shortening the built-in oil path, the total oil consumption of the system can be significantly reduced, accompanied by precise control, reduced pipeline pressure drop, throttling loss and overflow effect, reduced energy consumption and thermal load of the whole machine, meeting the market demand for low-carbon energy saving and green manufacturing.

[0014] 5. Flexible installation method The device can be directly loaded and connected with the driving mechanism and hydraulic actuator by using the integrated pump shell to obtain high integration and compactness, or it can be connected rigidly or installed separately through a hole connector to adapt to different layout requirements, taking into account universality.

[0015] 6. Adapt to high-precision servo control Combined with displacement, pressure / force or speed sensor signals, the device facilitates open-loop / closed-loop control of position / speed / force or torque; due to the built-in oil path and multifunctional cavity integrated pump shell, low-speed response and micro-motion controllability are improved, making it suitable for high-precision press fitting, positioning and process control scenarios.

[0016] 7. Extend and compensate for positive pressure In fast action or high flow demand, the multifunctional chamber can be connected to an external oil tank or an external auxiliary tank to provide positive pressure compensation and oil storage expansion to cover the oil supply needs of different cylinder diameters / travel or high dynamic applications. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 : Pump device integrated overall structure explosion diagram Figure 2 : Pump device integrated overall structure cross-sectional view Figure 3 : Pump device built-in axial plunger assembly device cross-sectional view Figure 4 : Pump device axial plunger assembly internal installation cross-sectional view Figure 5 : Pump device built-in radial plunger assembly diagram Figure 6 : Pump device built-in gear pair assembly diagram Figure 7 : Pump device driving long-stroke hydraulic cylinder diagram Figure 8 : Built-in oil path hole diagram Figure 9 : Built-in oil path schematic diagram Figure 10 : Pump shell overall structure Figure 11 : Pump device driving hydraulic cylinder diagram Figure 12 : Pump device driving hydraulic motor diagram Figure 13Pump device driving large hydraulic cylinder schematic diagram Figure 14 Pump device controlling hydraulic cylinder method schematic diagram Figure 15 Pump device controlling hydraulic motor method schematic diagram Figure 16 Pump device auxiliary oil tank schematic diagram Figure label explanation: 1 - driving mechanism, 1a - motor device, 1b - speed reducer; 2 - pump housing: 201 - first cover, 202 - intermediate housing, 203 - second cover; 204 - multifunctional chamber, 205 - sealing element, 206 - shaft seal; 207 - bearing, 208 - liquid level gauge observation window, 209 - oil filling port, 210 - oil drain plug; 211 - channel connector, 212 - external oil storage tank, 213 - external auxiliary oil tank; 214 - cooling fan, 215 - cooling pipe, 216 - connecting flange, 217 - large flow switch valve.

[0018] 3 - bidirectional oil pump assembly; 301 - pump shaft, 302 - swash plate, 303 - plunger cylinder, 304 - axial plunger, 305 - port plate; 311 - rotor cylinder, 312 - stator, 313 - radial plunger, 314 - central porting mechanism; 321 - driving gear, 322 - driven gear; 4 - displacement sensor; 5 - built-in oil circuit; 501 - first oil suction channel, 502 - second oil suction channel, 503 - first oil overflow channel, 504 - second oil overflow channel, 505 - first branch, 506 - second branch, 509 - oil pump leakage oil, 510 - oil suction and discharge one-way valve, 511 - oil suction one-way valve, 512 - first branch overflow valve, 513 - second branch overflow valve, 514 - second branch one-way valve, 518 - first branch pressure sensor, 519 - second branch pressure sensor; 6 - hydraulic cylinder; 7 - hydraulic motor. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] Overall structure of bidirectional electro-hydraulic pump device As Figure 1 ,Figure 2 、 Figure 3 The bidirectional servo electro-hydraulic pump device of the present application comprises: The pump housing 2 is composed of a first cover 201, an intermediate housing 202 and a second cover 203. The first cover 201 or the second cover 203 can be integrally formed with the intermediate housing 202 to improve the overall sealing performance and strength, reduce the material and processing costs, or can be manufactured separately and connected by a sealing element for easy assembly and maintenance.

[0021] The multifunctional chamber 204 is separately formed by the internal space of the intermediate housing 202, or is formed by the intermediate housing 202 and the first cover 201 and the second cover 203 at both ends, for accommodating the bidirectional oil pump assembly and storing working oil.

[0022] Under normal working conditions and without the need for additional connection of an external oil storage tank 212 or an external auxiliary oil tank 213, the minimum oil storage volume of the multifunctional chamber 204 theoretically involved in operation should not be less than 1 times or more than the maximum volume difference of the two cavities of the actuator, to ensure continuous oil circulation of the actuator during reciprocating cycle.

[0023] The sealing element: an oil-resistant sealing element 205, such as a fluorine rubber O-ring, is provided at the joint of the intermediate housing 202 and the first cover 201 and the second cover 203 to achieve static sealing of the multifunctional chamber 204 and prevent oil leakage.

[0024] Regarding the specific structure of the bidirectional oil pump assembly in this embodiment: As shown in Figures 1 to 6 The bidirectional oil pump assembly is installed inside the multifunctional chamber 204, with the oil pump shaft 301 penetrating through the first cover 201 or the second cover 203 and being supported by the bearing 207. The bearing 207 and the oil pump shaft 301 are provided with a shaft seal 206 structure to prevent leakage.

[0025] Bidirectional oil pump assembly 3 type: according to the best volumetric efficiency, a plunger assembly structure (including an axial plunger assembly and a radial plunger assembly) is preferred, and a gear assembly structure can also be used.

[0026] Among them, the axial plunger assembly includes an oil pump shaft 301, a swash plate 302, a plunger cylinder 303, an axial plunger 304 and a flow distribution disc 305.

[0027] Regarding the internal structure details of the axial plunger pump assembly: As shown in Figure 3 、 Figure 4As shown, the plunger cylinder body 303 and the distribution plate 305 are fixed to the inside of the second cover 203 in a pre-tightening manner. The interior is provided with a distribution channel arranged in an approximately symmetrical manner, which is connected to the multi-functional chamber 204 through a one-way valve. The oil pump shaft 301 drives the plunger cylinder body 303 to rotate. When the axial plunger 304 reciprocates, the internal volume of the chamber changes periodically, realizing oil suction and oil discharge.

[0028] like Figure 5 As shown, the radial plunger assembly includes a rotor cylinder 311, a stator 312, a radial plunger 313, and a central distribution mechanism 314.

[0029] The drive motor drives the rotor cylinder 311 to move forward and backward on the central distribution mechanism 314. The rotor cylinder 311 is radially divided into radial plungers 313. The tail of the radial plunger 313 is provided with a movable ball joint that slides against the inner ring of the stator 312. The inner ring of the stator 312 is eccentric to the center of the rotor cylinder 311, causing the volume of the radial plunger cavity to change periodically. The central distribution mechanism 314 forms two independent chambers, which are connected to the multi-functional chamber 204 through a one-way valve. Under the forward and reverse drive of the pump, the oil is alternately drawn in and discharged in both directions.

[0030] like Figure 6 As shown, the gear assembly includes a driving gear 321 and a driven gear 322. The cavity formed by the meshing and disengaging parts of the gear assembly and the gear body serves as the oil inlet and outlet. It is connected to the multi-functional chamber 204 via a one-way valve. Under the forward and reverse rotation drive of the driving gear 321, the oil can be drawn in and discharged in both directions.

[0031] Leakage return oil: The leakage oil generated during operation of the bidirectional oil pump assembly 3 through the various moving fit gaps directly flows back to the multi-functional chamber 204 to achieve cooling and lubrication.

[0032] Regarding built-in oil passage 5: like Figure 7 , Figure 8 , Figure 9 As shown, the interior of the second cover 203 is crisscrossed, establishing a passage between the two chambers of the bidirectional oil pump assembly 3, the oil storage chamber 204, and the hydraulic cylinder 6.

[0033] The pathways include: the main oil passage, the oil suction passage (including a check valve), and the oil overflow passage (including an oil overflow valve), forming a complete built-in oil circuit 5.

[0034] (1) Main oil passage: including the first branch 505 and the second branch 506, which respectively connect the two chambers of the bidirectional oil pump assembly 3 (oil suction or oil discharge) to the rodless chamber and the rod chamber of the hydraulic cylinder 6. By switching the forward and reverse rotation of the motor device 1a, the oil can be suctioned and discharged in both directions, driving the hydraulic cylinder 6 to work alternately.

[0035] (2) Oil suction passage: including first oil suction passage 501 and second oil suction passage 502, one end of the first oil suction passage 501 and the second oil suction passage 502 is communicated with the multifunctional chamber 204 via the oil suction and discharge one-way valve 510 or the oil suction one-way valve 511, and the other end is communicated with the bidirectional oil pump assembly 3 and the hydraulic oil cylinder 6, and the oil suction or oil discharge is realized by the forward and reverse rotation of the bidirectional oil pump assembly 3.

[0036] (3) Oil overflow passage: including first oil overflow passage 503 and second oil overflow passage 504, the first oil overflow passage 503 and the second oil overflow passage 504 are respectively arranged on the first branch 505 and the second branch 506 and are respectively connected with the first branch oil overflow valve 512 and the second branch oil overflow valve 513, when the system pressure exceeds the set value of the corresponding oil overflow valve, the excess oil is discharged back to the multifunctional chamber 204 through the oil overflow passage, and the overpressure protection function is realized.

[0037] The above-mentioned hole structure can be realized by drilling or casting forming mode.

[0038] Regarding the external structure and connection design: As shown in Figure 10 , Figure 11 , Functional interface: the shell is externally provided with an oil filling port 209 and an oil discharge plug 210, so as to facilitate oil replacement and maintenance.

[0039] Observation device: a liquid level observation window 208 is arranged on the middle shell, which is used for monitoring the oil amount.

[0040] Drive end structure: the first cover body 201 is provided with a mounting concave platform on the side facing the driving mechanism 1, the center axis of the concave platform is coaxial with the pump shaft 301, and the end face is provided with uniformly distributed screw holes, which are used for connecting with the flange of the motor device 1a or the speed reducer 1b.

[0041] Execution end structure: the second cover body 203 is provided with a convex platform, which is matched with the concave platform of the hydraulic oil cylinder 6 to form a rigid sealing connection. The internal oil channel directly communicates the two cavities of the bidirectional oil pump assembly 3 and the hydraulic oil cylinder 6, thereby reducing the external pipeline.

[0042] Regarding the driving mechanism 1: Figure 1 , Figure 2 As shown: The driving mechanism 1 can be a servo motor, a direct-current brushless motor, a stepping motor or a speed-regulating motor with a speed reducer 1b.

[0043] Preferably, a servo motor is adopted, which has fast response speed and high control precision, and realizes high-precision closed-loop servo control in combination with the low-backlash rigid connection of the application.

[0044] Connection: servo motor flange is fixed on the first cover concave by bolts, if including reducer 1b, the reducer shell is fixed with the concave, and the output shaft is coaxially and rigidly connected with the oil pump shaft 301.

[0045] In the embodiment of the application, the driving mechanism 1 can adopt a servo motor, and the output shaft of the servo motor can be connected with the pump shaft 301 of the bidirectional oil pump assembly 3 in different forms. One is a coaxial integrated structure, that is, the motor rotor shaft and the pump shaft 301 are formed as a whole by machining into the same shaft, and has the advantages of high concentricity, strong transmission rigidity and zero backlash.

[0046] Another is a split precision connection structure, for example, a low-backlash coupling, a taper sleeve locking connection, a key coupling or a tooth coupling, which can maintain high transmission precision and facilitate assembly, disassembly and maintenance.

[0047] The above two connection forms realize coaxial low-backlash transmission of the output shaft of the driving mechanism and the pump shaft, thereby ensuring the synchronization and control precision of the bidirectional servo electro-hydraulic pump device under forward and reverse rotation conditions.

[0048] Regarding servo control and closed-loop system: As shown in Figure 11 , Figure 12 , the pump device is used to drive a hydraulic oil cylinder 6 or a hydraulic motor 7 to realize open-loop or closed-loop control.

[0049] When the actuator is the hydraulic oil cylinder 6: the hydraulic oil cylinder piston rod is provided with displacement and pressure sensors, and the signals are fed back to the controller to realize position or force closed-loop control, and the control precision can be within 0.01 mm.

[0050] When the actuator is the hydraulic motor 7: the motor rotating shaft is provided with an encoder or a torque sensor to realize angle or torque closed-loop control.

[0051] As shown in Figure 14 , the controller, various sensors and motor drivers form a complete servo feedback and control loop. The controller adjusts the speed and direction of the servo motor according to real-time feedback, so that the pump assembly responds quickly through the shortest oil suction path to realize high-response servo control. The system can directly realize high-precision electro-hydraulic servo adjustment without external servo valves.

[0052] Regarding special application and expansion interface of the equipment: As shown in Figure 7 , Figure 13 , In some applications, for example, in the working condition requiring rapid liquid filling or large-flow liquid discharge, an external interface is arranged outside the pump shell 2 for connecting an external oil storage tank 212 or an external auxiliary oil tank 213 to expand the oil storage capacity and oil suction compensation capacity of the system.

[0053] When the actuator has a large cylinder diameter or requires high flow oil supply, the multi-functional chamber 204 formed in the pump housing 2 has a relatively insufficient volume, and the external oil tank 212 or external auxiliary tank 213 can serve as an oil pump oil suction compensation source to achieve dynamic replenishment of the oil in the multi-functional chamber 204.

[0054] In some embodiments, the liquid level or pressure of the external oil tank 212 or external auxiliary tank 213 can be set to be higher than that of the multi-functional chamber 204, thereby generating a hydrostatic pressure difference that provides positive pressure at the oil pump inlet, improves oil suction pressure, and improves oil suction stability at low speed.

[0055] The connecting flange 216 of the external auxiliary tank 213 is fixedly and sealingly connected to the housing of the hydraulic cylinder.

[0056] The external auxiliary tank 213 is preferably arranged on the rodless chamber side of the hydraulic cylinder, and a large flow switch valve 217 is connected in series in the rodless chamber oil circuit to achieve rapid liquid filling, rapid liquid discharge, and energy recovery functions while maintaining high dynamic response of the system.

[0057] As shown in Figure 13 , Figure 16 In the preferred embodiment, the external auxiliary tank 213 is internally provided with an oil cooling mechanism for heat exchange cooling of the return oil or oil in the tank.

[0058] The cooling mechanism can include any one or more of the following forms: (1) A heat dissipation fan 214 arranged on the outside or upper part of the auxiliary tank housing for oil cooling; (2) A cooling pipe 215 arranged inside the auxiliary tank, through which air, refrigerant or cooling water passes to achieve direct heat exchange between the oil and the coolant; (3) A temperature sensor and an electronic speed control fan linkage temperature control system arranged at the oil outlet or return passage to achieve automatic cooling adjustment.

[0059] Through the above structure, the external auxiliary tank not only has the functions of oil storage and oil suction compensation, but also can realize real-time control of oil temperature, improve the thermal stability and servo response consistency of the system.

[0060] This structure is particularly suitable for long-time high-power working occasions, such as servo hydraulic machines, servo presses and continuously operating electro-hydraulic servo actuator systems.

[0061] Through the cooperation of the structure and control mode, the device of the application significantly improves the system energy efficiency, flexible arrangement and control accuracy in application occasions with large cylinder diameter, high flow and high power density, and has the comprehensive performance advantages of high response and high integration.

[0062] In summary, through the above structure, the application realizes high integration design of the pump body, the oil tank and the valve group, and forms an integrated servo pump control unit. The oil pump assembly is directly immersed in flowing oil, and forced lubrication and cooling are obtained; the oil suction path is the shortest, the dynamic response is fast; the structure is compact, the leakage points are few, the control precision is high, and the application has significant substantial characteristics and significant progress.

[0063] Although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to part of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A bidirectional servo electro-hydraulic pump device, characterized in that: It includes a drive mechanism (1) and a pump housing (2). The pump housing (2) forms a closed multi-functional chamber (204). The multi-functional chamber (204) is equipped with a bidirectional oil pump assembly (3) and also serves as a working oil storage chamber, a leaked oil recovery chamber, and a pump suction chamber. In the pump housing (2) and / or the hole connector (211) that is fastened thereto, an internal oil passage (5) is formed by a through hole and / or combined with a valve. The internal oil passage is connected to the multifunctional chamber (204), the oil suction port of the bidirectional oil pump assembly (3) and the working chamber of the hydraulic actuator. The bidirectional oil pump assembly (3) achieves the interchange of the oil suction port and the oil outlet through the forward and reverse rotation of the drive mechanism (1), and is used to drive the hydraulic actuator.

2. The bidirectional servo electro-hydraulic pump device according to claim 1, characterized in that: The drive mechanism (1) is a motor device (1a) that can achieve controllable speed and direction. The motor device (1a) includes, but is not limited to, a servo motor, a brushless DC motor, a stepper motor, or a speed-regulating motor with a reducer (1b); The output shaft of the motor can be coaxial with the oil pump shaft to form an integrated shaft, or it can be driven by a separate shaft through a precision connection.

3. The bidirectional servo electro-hydraulic pump device according to claim 1, characterized in that: The hydraulic actuator includes a hydraulic cylinder (6), a hydraulic motor (7), a hydraulic oscillating actuator, or an execution unit that uses hydraulic oil as a medium to realize energy conversion and output.

4. The bidirectional servo electro-hydraulic pump device according to claim 1, characterized in that: The bidirectional oil pump assembly is: A component that uses axially or radially fitted plunger-cylinder assembly to achieve bidirectional oil suction and discharge; A meshing gear pair is used to achieve bidirectional oil suction and oil discharge components.

5. The bidirectional servo electro-hydraulic pump device according to claim 4, characterized in that: The bidirectional oil pump assembly (3) is an axial piston assembly, which mainly includes a pump shaft (301), a swashplate (302), a piston cylinder (303), an axial piston (304), and a distributor plate (305). The distribution plate (305) and the pump housing (2) form two independent distribution channels. The distribution channels are connected to the multifunctional chamber (204) via valves and are also connected to the actuator cavity. When the drive mechanism (1) rotates forward and backward, the oil pump assembly realizes bidirectional oil suction and oil discharge through the combination of the distribution channel and valve, so that the hydraulic oil alternately performs work in both directions between the two chambers of the actuator. The distribution plate (305) can be fitted or integrated into the pump housing (2).

6. The bidirectional servo electro-hydraulic pump device according to claim 4, characterized in that: The bidirectional oil pump assembly (3) is a radial plunger assembly with its cylinder arranged in an annular shape. The radial plunger (313) reciprocates radially and is connected to the multifunctional chamber (204) and the cavity of the hydraulic actuator through the central distribution mechanism (314).

7. The bidirectional servo electro-hydraulic pump device according to claim 1, characterized in that: The built-in oil circuit (5) is composed of valves and oil circuit channels within the pump housing (2) and / or the channel connector (211) that is fastened to it; The oil passage includes the main oil passage: the first branch (505) and the second branch (506); Oil suction channels: first oil suction channel (501), second oil suction channel (502); Oil spill channels: First oil spill channel (503) and second oil spill channel (504); The duct connector (211) includes, but is not limited to, transition seat, manifold plate, and end cover flange; The valve includes at least one of the following: a suction and discharge check valve (510), a suction check valve (511), a first branch overflow valve (512), and a second branch overflow valve (513), and the oil inlet or outlet of the valve is connected to the multifunctional chamber (204).

8. The bidirectional servo electro-hydraulic pump device according to claim 1, characterized in that: The pump housing (2) directly supports and connects the drive mechanism (1) and the hydraulic actuator, forming an integrated structure; It allows for a rigid connection to the hydraulic actuator via the pump housing (2) and the bore connector (211) that is fastened thereto, or a flexible, separate installation with the hydraulic actuator via a short pipeline.

9. A bidirectional servo electro-hydraulic pump device according to claim 3, characterized in that: The bidirectional servo electro-hydraulic pump device is used in hydraulically driven equipment, including hydraulic punch presses and servo presses; An external auxiliary oil tank (213) is provided on the rodless chamber side of the hydraulic cylinder (6), and a high-flow switching valve (217) is connected in series in the oil circuit from the external auxiliary oil tank (213) to the rodless chamber. The multifunctional chamber (204) maintains oil communication with the external auxiliary oil tank (213) through an external interface and / or built-in channel on the pump housing (2) to provide oil replenishment and return storage when the hydraulic cylinder (6) moves rapidly; The lowest liquid level of the external auxiliary oil tank (213) is higher than the lowest working liquid level of the multifunctional chamber (204), so that when the bidirectional oil pump assembly (3) is sucking oil, the oil pump inlet always maintains positive pressure compensation.

10. A bidirectional servo electro-hydraulic pump device according to claim 9, characterized in that: The external auxiliary oil tank (213) is equipped with a cooling mechanism for heat exchange and cooling of the oil in the external auxiliary oil tank (213).

11. A control method for a bidirectional servo electro-hydraulic pump device, based on the bidirectional servo electro-hydraulic pump device as described in any one of claims 1-10, characterized in that, include: The bidirectional oil pump assembly (3) is driven by the drive mechanism (1) to rotate in both directions, so as to realize the alternating action of hydraulic oil between the two chambers of the hydraulic actuator; When the hydraulic actuator is running at low speed, the bidirectional oil pump assembly (3) directly draws oil through the multifunctional chamber (204) formed in the pump housing (2), which shortens the oil suction path, reduces cavitation, and improves the stability of low-speed operation. When the working chamber pressure of the hydraulic actuator exceeds the preset threshold, the overflow channel built into the pump housing (2) or the hole connection (211) fastened thereto is automatically opened, and the overpressure oil flows directly back to the multi-functional chamber (204). A sensor for detecting the operating status of the hydraulic actuator is provided at the interface of the pump housing (2) and / or on the hydraulic actuator. The sensor feeds back the detection signal to the controller in real time to realize closed-loop servo control.

12. The control method for a bidirectional servo electro-hydraulic pump device according to claim 11, characterized in that: In the application scenario of controlling hydraulic cylinders (6): The position, speed or output force of the hydraulic cylinder piston rod can be detected in real time by sensors and displacement sensors (4) installed at the interface of the pump housing (2) or the rod end of the hydraulic cylinder (6); The controller compares the detection signal with the preset command signal and dynamically adjusts the speed and direction of the drive mechanism (1) based on the deviation signal; Under low-speed or micro-motion conditions of the hydraulic cylinder (6), the low-speed suction characteristics of the bidirectional oil pump assembly (3) are used to achieve high-precision positioning control, linear control and high dynamic response output control of the hydraulic cylinder piston rod.

13. The control method for a bidirectional servo electro-hydraulic pump device according to claim 11, characterized in that: In the application scenario of hydraulic motor (7): The rotation angle or speed of the hydraulic motor (7) can be detected in real time by using a rotary encoder or torque sensor installed on the pump housing (2) and connected to the hydraulic motor (7); The controller adjusts the output flow and direction of the bidirectional oil pump assembly in real time based on the sensor detection results; To achieve bidirectional rotation angle positioning and torque adjustment of the hydraulic motor (7).

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