A high-integration hydraulic power unit and working method

Abstract

This application provides a highly integrated hydraulic power unit and its working method, relating to the field of hydraulic system technology. The unit includes a housing, a hydraulic pump, and a motor. The housing has an oil storage chamber, and the hydraulic pump is connected to the oil storage chamber and pumps hydraulic oil under the drive of the motor. The built-in oil storage chamber allows the oil supply process to occur entirely within the housing, eliminating the need for an external oil supply system, effectively reducing the overall size of the pump, and avoiding exposed oil supply lines. This application features multiple return oil channels around the motor, utilizing the hydraulic oil circulation process to cool the motor, enabling the installation of a high-power motor to increase power density. Furthermore, by implementing pressure-holding and shock-prevention measures, this application ensures that the pressure inside the oil tank remains positive, preventing instantaneous high-pressure shocks to the hydraulic pump. This allows the motor pump to continue pumping oil normally under harsh conditions, adapting to the shaking and swaying of mobile equipment during operation, and meeting the requirements for stable operation under adverse conditions.

Description

Technical Field

[0001] This invention relates to the field of hydraulic system technology, and in particular to a highly integrated hydraulic power unit and its working method. Background Technology

[0002] The statements herein are provided only as background information in connection with this application and do not necessarily constitute prior art.

[0003] Hydraulic transmission technology is widely used in various engineering machinery, presses, aircraft and other large hydraulic equipment, and the hydraulic power unit is the core component of the hydraulic transmission system. Traditional hydraulic power units consist of distributed electric motors, hydraulic pumps, oil tanks, filters, safety valves, check valves, accumulators and hydraulic pipelines, etc. They are large in size and weight, and are mostly used in stationary hydraulic equipment and large engineering machinery where engines replace electric motors. They cannot be used in portable hydraulic shears for rescue, hydraulic spreaders, as well as lightweight mobile devices with strict weight requirements, such as bomb disposal and mobile hydraulic robotic arms, hydraulically driven legged robots, and hydraulically assisted exoskeletons.

[0004] Currently, some highly integrated hydraulic power units or components have emerged. For example, Chinese invention CN201811542519.7 – an integrated hydraulic power unit based on an external rotor motor – integrates the blades with the external rotor of the motor and installs them inside the oil tank to form an integrated hydraulic power unit; Chinese invention CN201610649248.X – a piston-type electro-hydraulic pump motor rotor-driven pump body structure – integrates the hydraulic pump with the internal rotor of the motor and allows the motor to directly drive the piston to rotate around the shaft to form an integrated electro-hydraulic pump. These highly integrated hydraulic power units or components achieve the integration of the motor and pump, but still require relatively complex external oil connections. The existing high-integration hydraulic power units lack measures to ensure the cleanliness of the hydraulic oil within the system and absorb pressure pulsations. They also lack pressure limiting measures to protect the hydraulic pump and prevent reverse impacts, failing to meet the installation requirements of lightweight mobile equipment. Furthermore, conventional high-integration hydraulic power units cannot adapt to harsh working conditions such as vibration, tilting, and even rolling during mobile equipment operation, thus failing to meet the full-condition working requirements of mobile equipment. Additionally, existing high-integration hydraulic power units or components do not use high-pressure oil circuit pressure changes to perform servo control of the motor speed, thus failing to automatically match the hydraulic pump output flow with the flow required by the hydraulic actuator, resulting in severe system overheating and limiting the power unit's power density. Summary of the Invention

[0005] The purpose of this application is to address the shortcomings of existing technologies by proposing a highly integrated hydraulic power unit and its working method. While ensuring the high integration of the hydraulic power unit, this method significantly improves the heat dissipation efficiency of the motor, effectively increases the power density, and meets the requirements of installation in confined spaces and use in complex working conditions for lightweight mobile equipment.

[0006] The primary objective of this application is to provide a highly integrated hydraulic power unit. One or more embodiments of this application provide the following technical solutions:

[0007] A highly integrated hydraulic power unit includes a housing, a hydraulic pump, and a motor, with the hydraulic pump and motor installed inside the housing. The housing is a sealed housing with an oil storage chamber inside, which is provided with a pump suction channel and a pump discharge channel communicating with the hydraulic pump.

[0008] The hydraulic pump includes a cylinder block, a drive shaft, a plunger, a return plate, a swashplate, and a distribution plate. The cylinder block is a cylindrical block with a through hole along its central axis to accommodate the drive shaft. The drive shaft is slidably connected to the inner wall of the through hole via a spline. A ball joint is provided on the drive shaft, and the ball joint is slidably connected to the drive shaft via a spline. One end of the plunger extends into a plunger hole on the cylinder block, and the cavity formed by its end face and the plunger hole communicates with the pump's oil suction channel or pump's oil discharge channel. The other end is connected to a slipper via a ball joint. The return plate has a central hole that mates with the ball joint via a spherical joint. The return plate also has a set of holes for the plunger to pass through. The swashplate is fixedly connected to the housing. A cylindrical spring and a support pin are installed in the through hole of the cylinder block. The spring preload acts on the plane of the cylinder block and the ball joint, ensuring that the cylinder block and the distribution plate, as well as the slipper and the swashplate, are always in close contact.

[0009] The motor drives the cylinder to rotate around its own central axis; as the cylinder rotates, the plunger reciprocates along the axial direction due to the action of the swashplate and the return plate, thereby repeatedly drawing oil from the oil storage chamber through the pump suction channel via the distribution plate and discharging it under high pressure from the pump discharge channel.

[0010] Furthermore, the oil storage chamber is also provided with an oil return channel; the housing is provided with a high-pressure oil port and an oil return port; the high-pressure oil port is connected to the pump discharge channel; and the oil return port is connected to the oil return channel.

[0011] Furthermore, the oil return channel is provided in multiple ways, and the multiple oil return channels are arranged at intervals around the motor.

[0012] Furthermore, a check valve is provided in the pump discharge channel to prevent hydraulic oil from flowing from the high-pressure port to the hydraulic pump.

[0013] Furthermore, a hollow elastic ball is placed inside the oil storage cavity; the hollow elastic ball pushes the hydraulic oil inside the oil storage cavity, making the pressure inside the oil storage cavity higher than the air pressure outside the shell.

[0014] Furthermore, the housing is provided with a first relief valve and a first relief valve outlet channel; the first relief valve connects the oil storage chamber and the first relief valve outlet channel; the first relief valve outlet channel is connected to the outside of the housing; when the hydraulic oil volume expands due to excessive return oil from the external hydraulic actuator or temperature rise, causing the pressure in the oil storage chamber to rise to the housing safety pressure, the first relief valve discharges a small amount of hydraulic oil through the first relief valve outlet channel.

[0015] Furthermore, the housing is provided with a second overflow valve and a second overflow valve oil outlet channel; the second overflow valve is connected to the pump discharge channel and the second overflow valve oil outlet channel; the second overflow valve oil outlet channel is connected to the oil storage chamber; when the pressure in the pump discharge channel rises to the system's set maximum working pressure, part of the hydraulic oil overflows back to the oil storage chamber through the inside of the second overflow valve.

[0016] Furthermore, the housing is equipped with a first pressure sensor, a second pressure sensor, and a temperature sensor; the first pressure sensor is used to detect the pressure in the oil reservoir; the second pressure sensor is used to detect the pressure in the high-pressure circuit; and the temperature sensor is used to detect the temperature of the hydraulic oil in the circuit.

[0017] Furthermore, a magnetic ring is provided at the end of the drive shaft away from the oil reservoir, and an encoder reading head that matches the magnetic ring is installed on the housing; the encoder reading head is used to read the rotational speed of the drive shaft.

[0018] Furthermore, it also includes a control box, which is installed on one side of the housing; the control box contains a motor pump controller, a motor servo drive board and a power management board; the motor pump controller is electrically connected to a first pressure sensor, a second pressure sensor, a temperature sensor, an encoder reading head and the motor servo drive board, and is used to monitor the working status of the hydraulic power unit and control the motor speed in real time.

[0019] A second objective of this application is to provide a method for operating the highly integrated hydraulic power unit, including the following:

[0020] Real-time monitoring of pressure P in the high-voltage circuit S With temperature T S The pressure P in the oil storage chamber T and motor speed V;

[0021] When P S Increase and gradually approach the maximum allowable pressure P of the hydraulic actuator. H At that time, reduce the motor speed V;

[0022] When P S Reduce and gradually approach the minimum pressure P required by the hydraulic actuator to meet the working requirements. L At that time, increase the motor speed V;

[0023] When P T When the pressure drops below atmospheric pressure, the motor will stop rotating.

[0024] Beneficial effects of the invention

[0025] 1. Considering the heat accumulation problem of motor caused by the high integration of hydraulic power unit, this application arranges multiple oil return channels around the motor and uses hydraulic oil circulation to dissipate heat from the motor. Compared with conventional high-integration hydraulic power units, which can only reduce heat generation by reducing motor power, this application provides good heat dissipation conditions for the motor by using hydraulic oil circulation. This allows this application to be free from the limitation of motor heat generation and to use a high-speed motor to improve the output capacity and power density of the power unit.

[0026] 2. This application effectively compresses the size of the motor and hydraulic pump by directly integrating the hydraulic pump inside the motor rotor. The motor and hydraulic pump are installed inside a housing with an oil storage chamber. At the same time, the housing integrates an overflow valve, a check valve, a pressure sensor, a temperature sensor, an oil suction filter, and an accumulator. They are connected through oil passages inside the housing to ensure that the internal oil circuit of the hydraulic pump can meet the requirements for absorbing pressure pulsations and the cleanliness of hydraulic oil. It also has the ability to limit oil pressure and prevent reverse flow of oil. That is, there is no need to connect to complex external oil circuits, which meets the oil supply needs of mobile hydraulic equipment under harsh working conditions such as vibration, tilting, and rolling.

[0027] 3. This application prevents damage to hydraulic components and housing in the high-pressure circuit from various pressure impacts by setting a first relief valve and a second relief valve; prevents damage to the hydraulic pump due to cavitation by setting a first pressure sensor to detect the pressure in the oil tank in real time; and avoids energy loss caused by a large amount of high-pressure oil overflow and reduces system heat generation by setting a second pressure sensor to detect the pressure in the high-pressure oil circuit in real time and perform servo control on the motor speed. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0029] Figure 1 This is a schematic diagram of the overall structure of the highly integrated hydraulic power unit in Embodiment 1 of this application;

[0030] Figure 2 This is a top view schematic diagram of the highly integrated hydraulic power unit in Embodiment 1 of this application;

[0031] Figure 3 This is a schematic cross-sectional view of the highly integrated hydraulic power unit in Embodiment 1 of this application (AA section).

[0032] Figure 4This is a schematic front view of the overall structure of the highly integrated hydraulic power unit in Embodiment 1 of this application;

[0033] Figure 5 This is a schematic cross-sectional view of the highly integrated hydraulic power unit in Embodiment 1 of this application (BB section).

[0034] Figure 6 This is a schematic diagram of the hydraulic system of the highly integrated hydraulic power unit in Embodiment 1 of this application;

[0035] The components are as follows: 1. Housing, 2. Oil tank cover, 3. Oil tank base, 4. Control box cover, 5. Accumulator, 6. First overflow valve, 7. First pressure sensor, 8. Second overflow valve, 9. Second pressure sensor, 10. Temperature sensor, 11. Motor servo drive board, 12. Motor pump controller, 13. Power management board, 14. Waterproof connector, 15. Power plug, 16. Communication plug, 17. Elastic ball, 18. Oil suction filter, 19. Screw plug, 20. Check valve, 21. Motor stator, 22. Motor rotor, 23. Rotor upper pressure plate, 24. Rotor lower pressure plate, 25. First bearing, 26. Distribution plate, 27. Drive shaft, 28. Cylinder block, 29. Elastic stop. 30. Cylindrical spring, 31. Support pin, 32. Piston, 33. Slipper, 34. Ball joint, 35. Return plate, 36. Swashplate, 37. Positioning pin, 38. Second bearing, 39. Magnetic ring, 40. Encoder reading head, 41. Base end cover, 42. First sealing ring, 43. Second sealing ring, 44. Third sealing ring, 45. Thin flat key, 46. Oil reservoir, 47. Battery, 48. Quick-connect coupling, 49. Motor, 50. Hydraulic pump, 51. High-pressure oil port, 52. Oil return port, 53. Pump suction channel, 54. Pump discharge channel, 55. Oil return channel, 56. First relief valve outlet channel, 57. Second relief valve outlet channel, 58. Cable channel. Detailed Implementation

[0036] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0039] As described in the background section, conventional hydraulic power units currently have low integration, which cannot meet the installation requirements of lightweight mobile equipment, nor can they adapt to harsh working conditions such as vibration, tilting, or even rolling when lightweight mobile equipment is in operation. This application proposes a highly integrated hydraulic power unit and method suitable for lightweight mobile hydraulic equipment.

[0040] Example 1

[0041] One typical implementation of this application is as follows: Figures 1-6 As shown, a highly integrated hydraulic power unit is provided.

[0042] refer to Figures 1-6 This embodiment proposes a highly integrated hydraulic power unit, including a housing 1, a hydraulic pump 50, and a motor 49, with the hydraulic pump and motor installed inside the housing. The housing is a sealed housing with an oil storage chamber 46 at the top. The housing has a pump suction channel 53 and a pump discharge channel 54 inside. The pump suction channel 53 is connected to the oil storage chamber 46 through an oil suction filter 18. The pump discharge channel 54 is connected to a high-pressure circuit and delivers the high-pressure oil discharged by the hydraulic pump to an external hydraulic actuator through a high-pressure oil port 51.

[0043] The top of the housing 1 is sealed by the oil tank cover 2 and the first sealing ring 42. The bottom of the housing 1 is sealed by the oil tank base 3 and the second sealing ring 43. The oil tank base 3 is sealed by the base end cover 41 and the third sealing ring 44. The cables of the encoder reading head 40 and the motor stator 21 are introduced into the control box through the cable channel 58 and sealed by the waterproof connector 14, so that the internal space of the housing 1 is completely sealed, that is, a completely closed oil storage chamber is formed.

[0044] Specifically, the motor stator 21 is fixed inside the housing 1 by the oil tank base 3. The motor rotor 22 is axially fixed to the cylinder 28 by the upper rotor pressure plate 23 and the lower rotor pressure plate 24. The motor rotor 22 and the cylinder 28 are circumferentially fixed by a thin flat key 45, so that the motor rotor 22 and the cylinder 28 rotate synchronously. The inner hole of the cylinder 28 is slidably connected to the drive shaft 27 by a spline. The drive shaft 27 is installed in the housing 1 by the first bearing 25 and the second bearing 38, and is axially fixed by the base end cover 41. An elastic retaining ring 29 is installed at the upper end of the inner hole of the cylinder 28. Three pin holes are evenly distributed around the axis at the spline. A support pin 31 is installed in the pin hole. The lower end of the support pin 31 abuts against the upper surface of the ball joint 34. A pre-compressed cylindrical spring 30 is installed between the upper end of the support pin 31 and the elastic retaining ring 29. A distribution plate 26 is provided between the upper end of the cylinder body 28 and the housing 1. Multiple plungers 32 are evenly arranged around the axis inside the cylinder body 28. The lower end of the plunger 32 is connected to the slipper 33 through a ball joint. The return plate 35 and the ball joint 34 are engaged by a ball joint. The elastic force of the cylindrical spring 30 tightly fits the upper surface of the cylinder body 28 with the distribution plate 26 and the slipper 33 with the swash plate 36. The swash plate 36 is fixed on the oil tank base 3 and is circumferentially fixed by the positioning pin 37.

[0045] When the motor rotor rotates, the plunger rotates with the cylinder block and, due to the action of the swashplate and return plate, generates a reciprocating motion along the cylinder block axis within the cylinder block, thereby continuously drawing oil from the oil reservoir and discharging it under high pressure through the pump's discharge channel.

[0046] The pump suction port is connected to the oil storage chamber at the upper end of the housing 1 through the pump suction channel 53, and an oil suction filter 18 is installed at the inlet. The pump discharge port is connected to the high-pressure circuit of the hydraulic power unit through the pump discharge channel 54, and a one-way valve 20 is installed in the pump discharge channel 54 to prevent the instantaneous high pressure generated in the high-pressure circuit from back impacting the hydraulic pump due to external force during the operation of the hydraulic power unit. The upper end of the discharge channel 54 is isolated from the high-pressure circuit and the oil storage chamber 46 by a screw plug 19.

[0047] In this embodiment, one or more hollow elastic balls 17 are placed inside the oil storage chamber 46. After the hydraulic power unit is assembled, the air inside the oil storage chamber 46 is first extracted using a vacuum pump, and then hydraulic oil is injected into the oil storage chamber 46 using a filling pump. The elastic force generated by the compressed elastic balls 17 keeps the hydraulic oil pressure inside the oil storage chamber 46 slightly higher than the external air pressure, forming a positive pressure closed circuit, thereby enabling the hydraulic power unit to adapt to harsh working conditions such as vibration, tilting, and even rolling.

[0048] Furthermore, such as Figures 3-5As shown, a second relief valve 8, an accumulator 5, a second pressure sensor 9, and a temperature sensor 10 are installed on the high-pressure circuit connected to the pump discharge port. The second relief valve 8 connects the pump discharge channel 54 and the second relief valve outlet channel 57; the second relief valve outlet channel 57 connects to the oil storage chamber 46; when the pressure in the pump discharge channel 54 is too high, some hydraulic oil overflows back to the oil storage chamber through the inside of the second relief valve 8, that is, the second relief valve 8 is used to limit the maximum output pressure of the power unit; the accumulator 5 is used to absorb pressure fluctuations in the high-pressure circuit; the second pressure sensor 9 and the temperature sensor 10 are used to detect the hydraulic oil pressure and temperature in the high-pressure circuit in real time;

[0049] A first relief valve 6, a first pressure sensor 7, a return oil channel 55, and a return oil port 52 are provided in the low-pressure circuit connected to the oil storage chamber. The first relief valve 6 connects the oil storage chamber 46 and the first relief valve outlet channel 56. The first relief valve outlet channel 56 is connected to the outside of the housing 1. When the hydraulic oil volume expands due to excessive return oil from the external hydraulic actuator or temperature rise, causing the pressure in the oil storage chamber 46 to rise to the housing safety pressure, the first relief valve discharges the hydraulic oil through the first relief valve outlet channel 56 to prevent damage to the oil tank seal. The first pressure sensor 7 detects the hydraulic oil pressure in the oil storage chamber 46 in real time.

[0050] It is understood that the high-pressure circuit, i.e. the pipeline between the pump discharge port of the hydraulic pump and the external hydraulic actuator, has a high pressure during operation; the low-pressure circuit, i.e. the pipeline between the external hydraulic actuator and the oil reservoir 46, has a consistently low hydraulic oil pressure.

[0051] In this embodiment, a return oil port 52 connected to the return oil pipeline of an external hydraulic actuator is provided at the lower part of the housing 1. Multiple return oil channels 55 connected to the return oil port 52 are machined inside the housing. The hydraulic oil returning from the external hydraulic actuator has a low temperature after external heat dissipation. When it flows back to the oil storage chamber 46 through the return oil channels 55, it carries away the heat generated by the motor stator 21 due to various losses, thereby cooling the motor. Compared with conventional hydraulic power unit motors that can only dissipate heat naturally, this application uses the hydraulic oil circulation process to dissipate heat from the motor, providing good heat dissipation conditions for the motor. This allows the application to use a high-speed motor to improve the output capacity and power density of the hydraulic power unit.

[0052] Furthermore, a control box is also provided on the side of the housing 1. The control box contains a motor pump controller 12, a motor servo drive board 11 and a power management board 13. A power plug 15 and a communication plug 16 are also installed on the side wall of the control box.

[0053] To monitor and control the operating status of the hydraulic power unit, a magnetic ring 39 is installed at the lower end of the drive shaft 27. An encoder reading head 40, which is used in conjunction with the magnetic ring 39, is installed inside the base end cover 41. The motor servo drive board 11 performs servo control on the rotational speed of the drive shaft 27 based on the feedback from the encoder reading head 40. The power management board 13 is connected to the external battery 47 through the power plug 15 and supplies power to the motor pump controller 12, the motor servo drive board 11, the first pressure sensor 9, the second pressure sensor 7, the encoder reading head 40, and the temperature sensor 10. The motor pump controller 12 receives the status parameters of the hydraulic power unit during operation from the motor servo drive board 11, the first pressure sensor 9, the second pressure sensor 7, the temperature sensor 10, and the power management board 13 in real time. At the same time, it receives instructions from the upper-level controller connected to the communication plug 16 and uploads the operating status data of the hydraulic power unit.

[0054] Example 2

[0055] This embodiment provides a method for operating the highly integrated hydraulic power unit described in Embodiment 1, including the following:

[0056] Real-time monitoring of pressure P in the high-voltage circuit S With temperature T S The pressure P in the oil storage chamber T and motor speed V;

[0057] When P S Increase and gradually approach the maximum allowable pressure P of the hydraulic actuator. H At that time, reduce the motor speed V;

[0058] When P S Reduce and gradually approach the minimum pressure P required by the hydraulic actuator to meet the working requirements. L At that time, increase the motor speed V;

[0059] When P T When the pressure is below atmospheric pressure, stop the motor and add hydraulic oil to P. T Higher than atmospheric pressure.

[0060] Specifically, before starting work, the battery 47 is connected to the power plug 15, the high-pressure oil port 51 and the return oil port 52 are connected to the hydraulic actuator through quick connectors 48 respectively, and the upper controller is connected to the motor pump controller 12 through the communication plug 16. The motor pump controller 12 receives the start and stop commands from the upper controller and sends them to the motor servo drive board 11 to start or stop the motor 49.

[0061] During operation, the motor pump controller 12 monitors the pressure P in the high-pressure circuit in real time. S (Detected by the second pressure sensor 9) and temperature T SThe parameters, including the pressure in the oil reservoir 46 (detected by temperature sensor 10), the pressure in the oil reservoir 46 (detected by first pressure sensor 7), and the motor speed V (detected by encoder reading head 40), are uploaded to the upper-level controller; the maximum allowable pressure of the hydraulic actuator is recorded as P. H (Set by the second relief valve 8), the minimum pressure to meet the working requirements is P. L ;

[0062] To achieve automatic matching between the output flow of hydraulic pump 50 and the flow required for the operation of the hydraulic actuator, and to avoid system overheating and energy waste caused by high-pressure hydraulic oil overflow, a closed-loop speed control loop for motor 49 is formed by motor pump controller 12, motor servo drive board 11, second pressure sensor 9, and encoder reading head 40. When P S Increases and gradually approaches P H At that time, the motor control circuit gradually reduces the speed of motor 49. When P S Decrease and gradually approach P L At that time, the motor control circuit gradually increases the speed of motor 49; when P is detected... T When the pressure is below atmospheric pressure, the motor pump controller 12 sends an alarm signal to the upper-level controller and sends a command to the motor servo drive board 11 to stop the operation of the motor 49, in order to prevent the hydraulic pump 50 from being damaged due to difficulty in oil suction.

[0063] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A highly integrated hydraulic power unit, characterized in that, It includes a housing, a hydraulic pump, and a motor, with the hydraulic pump and motor installed inside the housing; the housing is a sealed housing with an oil storage chamber inside, and the oil storage chamber is provided with a pump suction channel and a pump discharge channel that are connected to the hydraulic pump; The hydraulic pump includes a cylinder block, a drive shaft, a plunger, a return plate, a swashplate, and a distribution plate. The cylinder block is a cylindrical block with a through hole along its central axis to accommodate the drive shaft. The drive shaft is slidably connected to the inner wall of the through hole via a spline. A ball joint is provided on the drive shaft, and the ball joint is slidably connected to the drive shaft via a spline. One end of the plunger extends into a plunger hole on the cylinder block, and the cavity formed by its end face and the plunger hole communicates with the pump's oil suction channel or pump's oil discharge channel. The other end is connected to a slipper via a ball joint. The return plate has a central hole that mates with the ball joint via a spherical joint. The return plate also has a set of holes for the plunger to pass through. The swashplate is fixedly connected to the housing. A cylindrical spring and a support pin are installed in the through hole of the cylinder block. The spring preload acts on the cylinder block and the ball joint plane, ensuring that the cylinder block and the distribution plate, as well as the slipper and the swashplate, always maintain close contact. The motor drives the cylinder to rotate around its own central axis; as the cylinder rotates, the plunger reciprocates along the axial direction due to the action of the swashplate and the return plate, thereby repeatedly drawing oil from the oil storage chamber through the pump suction channel via the distribution plate and discharging it under high pressure from the pump discharge channel. A hollow elastic ball is provided inside the oil storage chamber; the hollow elastic ball pushes the hydraulic oil inside the oil storage chamber, making the pressure inside the oil storage chamber higher than the air pressure outside the shell; The motor stator is fixed inside the housing by the oil tank base, and the motor rotor is axially fixed to the cylinder by the upper rotor pressure plate and the lower rotor pressure plate. The motor rotor and the cylinder are circumferentially fixed by a thin flat key, so that the motor rotor and the cylinder rotate synchronously.

2. The highly integrated hydraulic power unit as described in claim 1, characterized in that, The oil storage chamber is also provided with an oil return channel; the housing is provided with a high-pressure oil port and an oil return port; the high-pressure oil port is connected to the pump oil discharge channel; the oil return port is connected to the oil return channel; there are multiple oil return channels, which are arranged at intervals around the motor.

3. The highly integrated hydraulic power unit as described in claim 1, characterized in that, The pump discharge channel is equipped with a check valve, which prevents hydraulic oil from flowing from the high-pressure port to the hydraulic pump.

4. The highly integrated hydraulic power unit as described in claim 1, characterized in that, The housing is provided with a first relief valve and a first relief valve oil outlet channel; the first relief valve connects the oil storage chamber and the first relief valve oil outlet channel; the first relief valve oil outlet channel is connected to the outside of the housing; when the pressure in the oil storage chamber rises to the housing safety pressure, the first relief valve discharges hydraulic oil from the first relief valve oil outlet channel.

5. The highly integrated hydraulic power unit as described in claim 1, characterized in that, The housing is provided with a second overflow valve and a second overflow valve oil outlet channel; the second overflow valve is connected to the pump discharge channel and the second overflow valve oil outlet channel; the second overflow valve oil outlet channel is connected to the oil storage chamber; when the pressure in the pump discharge channel rises to the maximum working pressure set by the system, part of the hydraulic oil overflows back to the oil storage chamber through the inside of the second overflow valve.

6. The highly integrated hydraulic power unit as described in claim 1, characterized in that, The housing is equipped with a first pressure sensor, a second pressure sensor, and a temperature sensor; the first pressure sensor is used to detect the pressure in the oil reservoir; the second pressure sensor is used to detect the pressure in the high-pressure circuit; and the temperature sensor is used to detect the temperature of the hydraulic oil in the circuit.

7. The highly integrated hydraulic power unit as described in claim 6, characterized in that, A magnetic ring is provided at the end of the drive shaft away from the oil reservoir, and an encoder reading head that matches the magnetic ring is installed on the housing; the encoder reading head is used to read the rotational speed of the drive shaft.

8. The highly integrated hydraulic power unit as described in claim 7, characterized in that, It also includes a control box, which is installed on one side of the housing; the control box contains a motor pump controller, a motor servo drive board and a power management board; the motor pump controller is electrically connected to a first pressure sensor, a second pressure sensor, a temperature sensor, an encoder reading head and the motor servo drive board, and is used to monitor the working status of the hydraulic power unit and control the motor speed in real time.

9. The method of operating the highly integrated hydraulic power unit according to any one of claims 1-8, characterized in that, Includes the following: Real-time monitoring of pressure P in the high-voltage circuit S With temperature T S The pressure P in the oil storage chamber T and motor speed V; When P S Increase and gradually approach the maximum allowable pressure P of the hydraulic actuator. H At that time, reduce the motor speed V; When P S Reduce and gradually approach the minimum pressure P required by the hydraulic actuator to meet the working requirements. L At that time, increase the motor speed V; When P T When the pressure drops below atmospheric pressure, the motor will stop rotating.

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