Radial integrated power unit, electro-hydraulic actuator and application

Abstract

The invention belongs to the field of power transmission and control, and discloses a radial integrated power unit, an electro-hydraulic actuator and application, the radial integrated power unit comprises an oil tank unit, an electro-hydraulic integrated assembly is arranged in the oil tank unit, and the electro-hydraulic integrated assembly comprises a driving shell communicated with an inner cavity of the oil tank unit; a hydraulic pump assembly and a motor assembly are coaxially nested in the driving shell in the radial direction, the hydraulic pump assembly comprises a main shaft, a sliding disc pair, a plunger pair and a flow distribution pair, the sliding disc pair comprises a swash plate and a sliding disc supported on the swash plate, the sliding disc pair or the flow distribution pair is communicated with the plunger pair, or the flow distribution pair and the sliding disc pair are both communicated with the plunger pair; the motor assembly comprises a rotor structure and a stator structure which are matched with the plunger pair; the oil tank unit comprises a unit shell and a valve assembly, the valve assembly comprises a valve block, and a control valve set is arranged on the valve block. The electro-hydraulic integrated actuator is highly integrated and has the advantages of being compact in structure, small in size, light in weight, high in overall power density, capable of achieving self-cooling and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of power transmission and control, and particularly relates to a radial integrated power unit, an electro-hydraulic actuator and application. BACKGROUND

[0002] The existing hydraulic system mostly adopts a centralized valve control system, which has the advantages of fast response and high precision, but also has problems such as large throttling loss, low system efficiency, complex pipeline, and serious system heating. For example, the driving system adopts an engine-variable pump-multiple valve-actuator, the engine drives the hydraulic pump, and the hydraulic energy is distributed to each actuator by the multiple valve. However, the existing centralized hydraulic system is based on the open valve control principle, and a large amount of energy is consumed at the throttle and overflow. At the same time, there are a large amount of along-the-way loss and local loss in the process, i.e. the pressure loss caused by the pipeline and hydraulic valve, etc. The overall efficiency of the hydraulic system is about 30%, and a large amount of hydraulic energy is lost and converted into heat energy, causing system heating and low system efficiency. At the same time, the existing centralized hydraulic system driving system has a long driving pipeline for centralized pressure oil supply, large oil consumption, and needs to be additionally provided with an oil tank and a cooling device, further increasing the system volume and cost.

[0003] The distributed pump control hydraulic system is a new hydraulic system in recent years, and especially with the development of electrification, the distributed pump control hydraulic system will become an important technology development trend for matching the development of electrification. The most important carrier of the distributed pump control hydraulic system is the electro-hydraulic actuator (EHA), which integrates the motor, hydraulic pump and oil cylinder, and directly uses the pump control actuator. The electro-hydraulic actuator (EHA) embodies the direction of high integration of hydraulic elements and motor electric control, and can fully play the advantages of high power weight ratio of hydraulic and control of electric power. The electro-hydraulic actuator (EHA) is first applied in the field of aerospace, for example, the on-board actuation system electro-hydraulic actuator (EHA) such as the rudder control system may use a new power electro-hydraulic actuator. Since the pipeline of the traditional centralized oil source hydraulic system extends to the entire aircraft body, it is not conducive to the light weight requirement of the aircraft. At the same time, it also faces various problems such as oil leakage and maintenance difficulty. At the same time, the traditional centralized oil circuit system increases the damage area of the aircraft, reduces the battlefield survivability of the fighter, and adopts the electro-hydraulic actuator EHA to replace the traditional electro-hydraulic actuation system with a central hydraulic source, which can reduce the overall weight of the aircraft, has better reliability, higher survivability, better maintainability, higher efficiency, and improved aircraft performance. At the same time, due to the reduction of fuel and the greatly improved aircraft availability, with the maturity of the electro-hydraulic actuator (EHA) technology and the reduction of the cost of elements, the distributed electro-hydraulic actuator (EHA) is expected to be widely used in the field of engineering machinery with the deep development of electrification.

[0004] From the perspective of existing electro-hydraulic actuator (EHA) product structures, integrating components such as the motor, hydraulic pump, control valve, oil tank, and cylinder into one unit significantly reduces or eliminates hydraulic lines compared to centralized hydraulic systems, resulting in a significant improvement in overall work efficiency. However, current products, in terms of structural compactness, integration, and overall power-to-weight ratio, still cannot meet the increasingly stringent requirements of engineering machinery, aerospace, and robotics fields regarding size, weight, power-to-weight ratio, reliability, and long service life. The main reasons are as follows:

[0005] (1) The existing electro-hydraulic actuator (EHA) power unit consists of a motor, hydraulic pump, coupling, oil tank, hydraulic valve, etc., which are simply integrated together in series and parallel. Each component occupies a large volume space and is heavy, resulting in a low overall power-to-weight ratio. For example, the existing electro-hydraulic actuator (EHA) used in the excavator boom system, where the boom system is the working execution part, has a cantilever structure during operation, which has strict requirements on volume and weight. However, the power unit of the existing electro-hydraulic actuator (EHA) occupies a large space and significantly increases the weight of the boom, thus increasing the design difficulty of the boom and also affecting the simplicity and aesthetics of the boom.

[0006] (2) Some electro-hydraulic actuators (EHA) use gear pumps, which generally operate at medium pressure or below. Therefore, they are difficult to meet the requirements for long-term use in engineering machinery and other fields that require high-pressure operation.

[0007] (3) Existing electro-hydraulic actuators (EHA) often adopt a pump-controlled closed system. The oil reversal is achieved by the motor, which can rotate in both directions. The repeated high-frequency reversal of the motor under high-speed conditions with high rotational inertia can easily lead to motor damage. At the same time, the hydraulic pump adopts a hydraulic pump that can work in four quadrants. Therefore, the overall price is high and difficult to afford in the field of engineering machinery.

[0008] (4) Some electro-hydraulic actuators (EHA) use axial piston pumps, mainly swashplate piston pumps with slipper type. Due to inherent defects in their structural design, these piston pumps have unbalanced forces and torques in the friction pair, which can easily lead to problems such as lateral overturning, wear and burning of the disc. Especially when used in conjunction with a high-speed motor, this further aggravates the wear and failure of the piston pump.

[0009] It is evident that existing electro-hydraulic actuator technologies still have room for improvement, and more reasonable technical solutions need to be proposed to address the technical problems existing in the current technology. Summary of the Invention

[0010] The purpose of this invention is to address the problems existing in current electro-hydraulic actuators in distributed hydraulic systems by providing a novel radial integrated power unit and actuator that features a highly compact structure, small size, light weight, low noise, high efficiency and energy saving, and high power density.

[0011] To achieve the above objectives, the power unit employed in this invention includes:

[0012] A radially integrated power unit includes an oil tank unit for containing hydraulic oil. An electro-hydraulic integrated assembly is disposed within the oil tank unit. The electro-hydraulic integrated assembly includes a drive housing that communicates with the inner cavity of the oil tank unit. A hydraulic pump assembly and a motor assembly that rotate synchronously are coaxially arranged radially within the drive housing. The hydraulic pump assembly includes a main shaft, a sliding plate pair, a plunger pair, and a flow distribution pair. The sliding plate pair includes a swashplate and a sliding plate supported on the swashplate and having an integral disc structure. The sliding plate pair or the flow distribution pair communicates with the plunger pair to form an oil passage and cooperates with the plunger pair to perform oil suction and oil pressure. Alternatively, both the flow distribution pair and the sliding plate pair communicate with the plunger pair to form an oil passage and cooperate with the plunger pair to perform oil suction and oil pressure.

[0013] The motor assembly includes a rotor structure that cooperates with and rotates coaxially with a plunger pair, and a stator structure disposed within a drive housing. A rotational gap is formed between the rotor structure and the stator structure and is filled with oil.

[0014] The oil tank unit includes a unit housing and a valve assembly. The valve assembly includes a valve block that is connected and cooperates with the unit housing. The valve block is provided with a control valve group for controlling the direction, and / or flow rate, and / or pressure of the hydraulic oil.

[0015] The aforementioned power unit, with its motor and pump coaxially nested, significantly improves the overall integration of the power unit. The motor assembly, when energized, drives the hydraulic pump assembly to perform oil suction and pressure processes. The hydraulic pump assembly, submerged in the oil tank, maintains continuous oil suction with low noise while simultaneously delivering high-pressure hydraulic fluid for continuous drive output, ensuring smooth operation of external loads. The hydraulic oil in the tank submerges the pump body, which has an inlet to allow hydraulic oil to enter the inner cavity of the drive housing. After suction and pressure actions by the plunger assembly, high-pressure hydraulic oil is delivered as the driving medium.

[0016] In the above scheme, when the sliding plate pair or the distribution pair is connected to the plunger pair to form an oil circuit, the power unit constitutes a closed system and realizes oil suction and oil pressure from the sliding plate pair or the distribution pair. Under this structure, the motor assembly can achieve bidirectional operation and output oil from different oil circuits, and can be controlled and regulated through various oil circuit structures. When both the sliding plate pair and the distribution pair are connected to the plunger pair to form an oil circuit, the power unit constitutes an open system. Under this structure, the motor assembly can only perform unidirectional rotation and output oil from a fixed oil circuit and be controlled and regulated through a predetermined oil circuit structure.

[0017] As a component for storing and supplying hydraulic oil, the oil level inside the tank unit fluctuates during use, causing pressure changes within the unit. To avoid impacting the operation of the electro-hydraulic integrated assembly and ensure stable oil intake, an oil balancing component regulates the pressure within the tank unit. Various solutions can be implemented, and there is no single, limited approach. Here, we propose one feasible option: the tank unit is equipped with an oil balancing component, which includes an elastic container filled with gas and completely submerged in the hydraulic oil. The elastic container is connected to a venting valve assembly. In this design, the volume of the elastic container increases with the amount of gas added. When the hydraulic oil level drops after circulation, some gas is added to the elastic container to increase its volume, thus raising the hydraulic oil level and ensuring smooth oil intake for the hydraulic pump assembly. When the hydraulic oil returns to the tank unit, causing the level to rise, some gas is released from the elastic container, reducing its volume and lowering the oil level. The oil balance component ensures the gas-liquid balance within the oil tank unit.

[0018] Furthermore, the drive housing is used to connect and fix the motor assembly and the hydraulic pump assembly. Its structure can be constructed in various forms to cooperate with the oil tank unit and valve assembly to form a stable oil suction and pressure structure. The structure of the drive housing is not limited to a single one. Here, we optimize and propose one feasible option: the drive housing is connected to a detachable end cap to form a sealed cylindrical structure. The two ends of the main shaft are respectively engaged with the two end faces of the cylindrical structure. One end of the cylindrical structure is provided with an oil passage and connects to the inner cavity of the oil tank unit to form an oil inlet path. The other end of the cylindrical structure is provided with an oil outlet and fits against the valve block to form an oil outlet path. With this solution, the cylindrical structure can be open at both ends and covered with end caps. Both ends of the main shaft are connected and engaged with the end caps, and the end caps adjacent to the valve assembly are connected to the valve assembly to form an oil outlet path.

[0019] Furthermore, in this invention, the drive housing structure can also be constructed in another form. Here, we optimize and propose a feasible option: the drive housing forms a cylindrical structure with one end sealed and the other end open. An oil inlet is provided at the sealed end of the cylinder. The open end of the cylinder structure is connected to a valve block to seal the cylinder structure. One end of the main shaft is connected to the sealed end of the cylinder structure, and the other end of the main shaft is connected to the valve block. The sliding plate pair cooperates with the valve block to form an oil outlet passage. With this solution, the sealed end of the drive housing can be sealed with an end cap, or the drive housing can be integrally formed as a sealed structure. This results in fewer disassembly structures for the drive housing and higher overall stability.

[0020] Furthermore, in this invention, the structure of the drive housing can also be constructed in another form. Here, we optimize and propose a feasible option: the drive housing forms a cylindrical structure with one end sealed and the other end open. The sealed end of the cylinder is provided with an oil inlet, and the open end of the cylinder structure is connected to a valve block to seal the cylinder structure. One end of the main shaft is connected to the sealed end of the cylinder structure, and the other end of the main shaft is connected to the valve block. The oil distribution pair includes a distribution block sleeved on the main shaft. One end of the distribution block is connected to the valve block, and the other end of the distribution block is pressed against a distribution plate. The distribution block and the distribution plate are respectively provided with low-pressure distribution ports and / or high-pressure distribution ports, which are respectively connected to form an oil passage. When the plunger pair rotates to connect with the low-pressure distribution port, oil is drawn in; when the plunger pair rotates to connect with the high-pressure distribution port, oil is compressed. With this solution, the sealed end of the drive housing can be sealed with an end cap, or the drive housing can be directly integrally formed into a sealed structure. Thus, the drive housing has fewer disassembly structures and higher overall stability.

[0021] Furthermore, in this invention, the oil distribution pair, as one of the structures that abuts the rotating plunger pair, can be constructed in various forms and is not limited to a single one. Here, we optimize and propose one feasible option: the oil distribution pair includes a support member sleeved on the main shaft, one end of which is connected and fixed to the drive housing, and the other end of which abuts against the oil distribution plate. With this design, the oil distribution pair ensures the smooth and reliable rotation of the plunger pair, making the oil suction and pressure actions of the plunger pair more stable during rotation.

[0022] Furthermore, the oil distribution assembly can also be constructed as one of the oil inlet and outlet structures of the plunger assembly. The specific method is not limited to one particular approach. Here, we optimize and propose one feasible option: the support member forms an internal cavity, and the support member is provided with an oil passage connecting the cavity and the inner cavity of the drive housing. The oil distribution plate is provided with a low-pressure oil port that connects to the cavity. When the cylinder rotates and connects to the low-pressure oil port, oil is drawn in. With this scheme, the support member can be constructed as a hollow platform-shaped component. Its side surface can be provided with radial oil inlets to guide hydraulic oil into its internal cavity, and then from the transverse oil inlet on the end face to the low-pressure distribution port of the distribution plate. When the cylinder rotates to connect the high and low pressure distribution ports, the hydraulic oil enters the plunger assembly.

[0023] Furthermore, in this invention, the sliding plate pair is used to cooperate with the rotation of the plunger pair and simultaneously realize the oil suction and oil pressure of the plunger pair. The sliding plate pair can be constructed in various forms and is not limited to one. Here, optimization is carried out and one feasible option is proposed: The sliding plate pair includes a swashplate sleeved on the main shaft. The swashplate is provided with a mounting surface for tilting the sliding plate. The sliding plate is sleeved on the main shaft and simultaneously fits the mounting surface. The sliding plate is provided with a plunger ball socket for fitting the plunger end. The plunger end is slidably embedded in the plunger ball socket by a pressure plate. The plunger ball socket passes through the sliding plate through a waist-shaped hole. The swashplate is provided with a swashplate high-pressure distribution groove and / or a swashplate low-pressure distribution groove. When the cylinder rotates and the swashplate waist-shaped hole connects to the swashplate high-pressure distribution groove, oil is pressured outward. When the cylinder rotates and the swashplate waist-shaped hole connects to the swashplate low-pressure distribution groove, oil is sucked in from the outside.

[0024] Furthermore, the mating structure of the sliding plate pair and the plunger pair in this invention can be adjusted to achieve oil suction and oil pressure with different mating structures, thereby increasing the oil suction and oil pressure. The specific mating structure is not limited to one thing. Here, we optimize and propose one feasible option: the sliding plate pair is symmetrically arranged on both sides of the plunger pair, and both ends of the plunger pair are provided with plungers that mate with the sliding plate pair and reciprocate to both sides to simultaneously suction and press oil. The swashplate in the sliding plate pair that mates with the oil outlet is provided with a swashplate high-pressure distribution groove and a swashplate low-pressure distribution groove for suction and oil pressure. The swashplate in the sliding plate pair away from the oil outlet is provided with a swashplate low-pressure distribution groove for suction.

[0025] Furthermore, the structure of the plunger assembly is not limited to a single option. Here, we propose one feasible choice: the plunger assembly includes a cylinder body and plungers spaced circumferentially on the cylinder body. The cylinder body has plunger holes in which the plungers slide. The cylinder body is fitted onto a spindle, which also has a return mechanism for pressing against the cylinder body and an initial sealing device to prevent leakage. With this design, the return mechanism applies a pressing force to the cylinder body and the sliding plate assembly, helping the cylinder body maintain a relatively stable rotational position. When the cylinder body rotates, the plungers reciprocate, achieving oil suction and pressure. The initial sealing device maintains the sealing between the plunger assembly and the sliding plate assembly, preventing hydraulic oil leakage after it reaches the sliding plate assembly from the plunger assembly.

[0026] Furthermore, the return mechanism can be constructed in various forms, and its structure is not limited to a single one. Here, we optimize and propose one feasible option: the return mechanism includes a central spring, which is sleeved on the main shaft. The front end of the central spring is engaged with the slide plate via a ball joint, and the rear end of the central spring is engaged with the cylinder body via a retaining ring. With this scheme, the ball joint and the slide plate are connected in a stable manner, even during the rotation of the slide plate. The retaining ring is a hard retaining ring, which is coaxially sleeved on the main shaft and pressed tightly against the cylinder body under the thrust of the central spring.

[0027] Furthermore, to improve the overall heat dissipation capacity of the power unit and reduce its temperature during operation, optimizations are proposed, including some feasible options: the fuel tank unit's housing is equipped with a heat dissipation and cooling structure; this structure includes heat sinks on the housing or a circulating cooling assembly, which includes a circulating cooling channel surrounding the housing, with a circulating medium inlet and outlet. With this design, the heat sinks increase the fuel tank unit's heat dissipation area, enabling heat dissipation; the circulating cooling assembly can use gas or liquid as the circulating medium, which transfers heat within the circulating cooling channel, carrying away heat from the fuel tank unit and thus assisting in cooling the fuel tank unit and its internal electro-hydraulic integrated unit.

[0028] The above describes the structural composition of the power unit. This invention also discloses an electro-hydraulic actuator, which will be described below.

[0029] An electro-hydraulic actuator utilizes the power unit described above. The oil outlet structure of the power unit is connected to an oil distribution pipeline, which is connected to a hydraulic cylinder assembly used to drive a load. The hydraulic cylinder assembly includes a cylinder barrel, a piston rod disposed within the cylinder barrel, and the piston rod divides the cylinder barrel into two actuating chambers. Each actuating chamber is provided with an oil port. The oil distribution pipeline is respectively connected to the oil ports of the two actuating chambers and the oil inlet is controlled by a control valve. The front end of the piston rod is provided with a drive connection structure for connecting and driving the load. The hydraulic cylinder assembly includes an asymmetrical single-outlet rod structure or a symmetrical double-outlet rod structure.

[0030] The electro-hydraulic actuator disclosed above connects and cooperates with the power unit and the hydraulic cylinder assembly, and supplies hydraulic oil to the hydraulic cylinder assembly as the driving medium through the power unit. This can maintain a stable and reliable driving force, and at the same time, the reciprocating motion of the hydraulic cylinder assembly is realized under the regulation of the control valve, thereby driving the load.

[0031] The present invention also discloses a method for applying an electro-hydraulic actuator, which is described below.

[0032] The application of electro-hydraulic actuators is applicable to the electro-hydraulic actuators described above. These electro-hydraulic actuators constitute a one-way open system, with the motor assembly operating in one direction. The control valve group includes at least one directional valve, one relief valve, and one check valve. The working port of the directional valve is connected to both chambers of the actuator, the oil inlet of the directional valve is connected to the outlet of the hydraulic pump assembly, the inlet of the relief valve is connected to the outlet of the hydraulic pump assembly, and the outlet of the relief valve is connected to the inner cavity of the drive housing. High-pressure oil is supplied to the actuator from the output of the hydraulic pump assembly, and the inner cavity of the drive housing receives the return oil from the actuator.

[0033] The application of electro-hydraulic actuators is applicable to the electro-hydraulic actuators mentioned above. The electro-hydraulic actuators constitute a closed system, and the motor assembly and hydraulic pump assembly can operate in both directions. High-pressure oil is output from the hydraulic pump assembly, delivered to the actuator via the valve block, and then returned to the hydraulic pump assembly via the valve block. The valve block is equipped with a control valve group, which includes at least two relief valves, two replenishing check valves, and one electromagnetic unloading valve connected to the main oil circuit. The control valve group can also be equipped with a balance valve or a hydraulically controlled check valve according to the working conditions.

[0034] Compared with the prior art, some of the beneficial effects that the present invention can achieve include:

[0035] The power unit in this invention highly integrates the motor and hydraulic pump structure, reducing the need for couplings, oil pipelines, and other structures, and decreasing the axial length of the power unit. This results in a more streamlined and compact structure, smaller size, and more flexible and convenient control operation in the hydraulic control system. The more streamlined structure reduces the total weight of the power unit and load, shortens the control oil circuit, and reduces energy consumption during the control process. At the same time, the electro-hydraulic integrated unit is immersed in hydraulic oil, which helps reduce noise and promotes heat dissipation and transfer, improving the working stability and reliability of the motor and hydraulic pump components.

[0036] Furthermore, the valve block and the connecting block are configured as an integral structure. The integral valve block is connected to the cylinder and closes the opening on one side of the cylinder. The integral valve block integrates a control valve. Attached Figure Description

[0037] Figure 1 This is an embodiment of the open electro-hydraulic actuator of the present invention.

[0038] Figure 2 This is the power unit structure of the open electro-hydraulic integrated actuator in this invention.

[0039] Figure 3 In this invention Figure 2 AA section view.

[0040] Figure 4 This is a system schematic diagram of the open electro-hydraulic integrated actuator in this invention.

[0041] Figure 5 This is a plan view of one end of the slide in this invention.

[0042] Figure 6 for Figure 5 BB cross-sectional view of the middle sliding plate structure.

[0043] Figure 7 This is a flow diagram of the internal fluid flow of the power unit in the open electro-hydraulic actuator of the present invention.

[0044] Figure 8 This is another embodiment of the open electro-hydraulic integrated power unit in this invention.

[0045] Figure 9 This is an embodiment of the dual-inlet open electro-hydraulic integrated power unit of the present invention.

[0046] Figure 10 This is an embodiment of the double-swashplate open electro-hydraulic integrated power unit in this invention.

[0047] Figure 11 This is an embodiment of the closed-loop electro-hydraulic actuator of the present invention.

[0048] Figure 12 This is the power unit structure of the closed electro-hydraulic integrated actuator in this invention.

[0049] Figure 13 In this invention Figure 12 AA section view.

[0050] Figure 14 This is a system schematic diagram of the closed electro-hydraulic integrated actuator in this invention.

[0051] Figure 15 This is another embodiment of the closed electro-hydraulic actuator of the present invention.

[0052] Figure 16 This is an embodiment of the electro-hydraulic integrated actuator in this invention, in which the valve block and connecting block are integrated.

[0053] The diagram shows the following markings: 1. Unit housing; 2. Electro-hydraulic integrated assembly; 3. Motor assembly; 4. Hydraulic pump assembly; 5. Valve assembly; 6. Oil balance assembly; 7. Control assembly; 8. Hydraulic cylinder assembly; 11. First cavity; 12. Heat dissipation and cooling device; 13. Heat sink; 14. Cooling water inlet; 15. Cooling water outlet; 16. Cooling channel; 21. Drive housing; 22. End cover; 22a. Left end cover; 22b. Right end cover; 23. Bearing; 24. Oil passage; 25. Oil outlet; 6. Main shaft; 27. Second cavity; 29. ​​Second oil port; 31. Stator assembly; 32. Rotor assembly; 33. Permanent magnet; 34. Rotary drum; 41. Cylinder block; 42. Distribution plate; 43. Piston; 44. Pressure plate; 45. Sliding plate; 46. Swashplate; 47. Return mechanism; 48. Support block; 49. Oil distribution block; 50. Valve block; 51. Directional valve; 52. Inlet / outlet oil port; 53. First relief valve; 54. Second relief valve; 55. Electromagnetic unloading valve; 56. First hydraulic check valve; 57. Second hydraulic check valve. 58. Check valve; 59. Filter; 61. Container cavity; 62. Flexible container; 63. Valve assembly; 81. Cylinder; 82. Piston rod; 83. Guide seat; 84. Piston; 85. Connecting block; 86a. Rodless chamber inlet / outlet; 86b. Rod chamber inlet / outlet; 87. Rod chamber; 88. Rodless chamber; 116. Oil; 210. Impeller assembly; 411. Piston hole; 421. First distribution port; 422. Second distribution port; 431. Piston center hole; 45. 1. Sliding plate hydrostatic support surface; 452. Sliding plate boss surface; 453. Sliding plate waist-shaped hole; 454. Sliding plate outer sealing part; 455. Sliding plate inner sealing part; 456. Sliding plate interval sealing part; 458. Plunger ball socket; 461. First swashplate distribution groove; 462. Second swashplate distribution groove; 481. Radial oil inlet; 482. Lateral oil inlet; 483. Third cavity; 491. First distribution groove; 492. Second distribution groove; A / B. Reversing valve working port; P. Reversing valve oil inlet; T. Reversing valve return port. Detailed Implementation

[0054] The present invention will now be described in detail with reference to the accompanying drawings.

[0055] While the invention is permissible in various forms, this specification and drawings only disclose certain specific forms as exemplified by the invention. However, the invention is not intended to be limited to the described embodiments. The scope of the invention is set forth in the appended claims.

[0056] For ease of description, embodiments of the present invention are shown in a typical orientation such that when the central axis of the main shaft of the electro-hydraulic integrated power unit is horizontally positioned with the valve assembly to the right, the terms “longitudinal,” “lateral,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “horizontal,” “bottom,” “inner,” and “outer” used in the description are all used with reference to this position and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or a specific orientation construction and operation. It should be understood that the present invention can be manufactured, stored, transported, used, and sold in orientations other than those described.

[0057] Example 1

[0058] like Figures 1 to 7 The figure shows a preferred embodiment of the electro-hydraulic actuator of the present invention. In the preferred embodiment shown, the electro-hydraulic actuator is a highly integrated open system, including a hydraulic cylinder assembly 8 for driving the load and an electro-hydraulic power unit 9 for providing hydraulic power. The hydraulic cylinder assembly 8 includes a cylinder barrel 81, a piston rod 82, a guide seat 83, a piston 84, and a connecting block 85. The piston 84 divides the cylinder barrel 81 into two chambers: a rod chamber 87 and a rodless chamber 88. The connecting block 84 is fixedly connected to the cylinder barrel 81.

[0059] The electro-hydraulic integrated power unit 9 is a highly integrated one-piece structure, comprising a unit housing 1, an electro-hydraulic integrated component 2, a valve assembly 5, and an oil balance assembly 6. One end of the unit housing 1 is connected to the valve assembly 3 to form a closed first cavity 11. The electro-hydraulic integrated component 2 and the oil balance assembly 6 are housed within the first cavity 11 and submerged in oil. The electro-hydraulic integrated component 2 includes a drive housing 21, an end cap 22, a motor assembly 3, and a hydraulic pump assembly 4. The electro-hydraulic integrated component 2 is connected to the valve assembly 5. The drive housing 21 and the end cap 22 form a second cavity 27. The motor assembly 3 and the hydraulic pump assembly 4 are housed in the second cavity 27. The motor assembly 3 and the hydraulic pump assembly 4 share the drive housing 21 and the main shaft 26. The valve block 50 in the valve assembly 5 is connected to the connecting block 85. The oil inlet and outlet in the valve block 50 are connected to the oil inlet and outlet on the connecting block 85. The high-pressure oil, driven by the electro-hydraulic integrated power unit, is transported through the valve assembly 5 and the connecting block 85 to the rod chamber 87 or rodless chamber 88 of the cylinder, thereby realizing the extension and retraction of the piston rod 82. The oil balance assembly 6 is used to balance the imbalance of oil inlet and outlet and provide a certain pressure.

[0060] like Figure 4 This is a system schematic diagram of an open electro-hydraulic actuator, combined with... Figure 1 Structural diagram and Figure 4The system schematic diagram is used for illustration. The motor assembly 3 operates in one direction. The valve assembly 5 includes at least a directional valve 53, a relief valve 54, and a check valve 57. The working ports (A and B ports) of the directional valve 53 are connected to either the rod-side chamber 87 or the rodless chamber 88 of the actuator. The oil inlet (P port) of the directional valve 53 is connected to the outlet of the hydraulic pump assembly. A check valve 57 is installed between the hydraulic pump assembly 4 and the directional valve 53. The inlet of the relief valve 54 is connected to the outlet of the hydraulic pump assembly, and the outlet of the relief valve 54 is connected to either the first cavity 11 or the second cavity 27. The second cavity 27 is connected to... The first cavity 11 is connected through the oil passage 24. During operation, the low-pressure oil 11 in the first cavity enters the second cavity 27 through the oil passage 24. The oil in the second cavity 27 enters the hydraulic pump assembly 4 and, under its action, delivers high-pressure oil to the rod chamber 87 or rodless chamber 88 of the cylinder assembly 8 through the valve assembly 5. The reversing valve 53 is used to control the extension and retraction of the piston rod 82. The first cavity 11 or the second cavity 27 receives the return oil. The oil balance assembly 6 is used to balance the imbalance of oil inflow and outflow and provide a certain pressure.

[0061] As can be seen from the above structure, volumetric speed regulation is achieved by relying on the unidirectional speed change of the motor assembly and the oil reversing is realized through the reversing valve. This structure can significantly reduce the overall cost on the one hand, and avoid motor damage caused by repeated high-frequency reversing under high-speed conditions with high rotational inertia on the other hand.

[0062] The connecting block of the hydraulic cylinder assembly 8 is provided with a rodless chamber inlet / outlet port 86a and a rod chamber inlet / outlet port 86b. The rodless chamber inlet / outlet port 86a communicates with the rodless chamber 88 through an internal oil passage in the connecting block 85, while the rod chamber inlet / outlet port 86b communicates with a working oil port located on the connecting block 85 or valve block 50 via an oil pipe. The piston 84 on the hydraulic cylinder assembly 8 is connected to the end of the piston rod 82. The piston 84 is provided with multiple sealing rings and guide rings (not labeled). The guide seat 83 is fixedly connected to the cylinder barrel 81 and is provided with sealing rings, guide rings, and dustproof rings. It should be noted that this embodiment shows an asymmetrical single-rod hydraulic cylinder; predictably, the present invention is also applicable to symmetrical double-rod hydraulic cylinders.

[0063] The electro-hydraulic integrated assembly 2 includes a drive housing 21, a left end cover 22a, a right end cover 22b, a motor assembly 3, a hydraulic pump assembly 4, and a main shaft 26. The drive housing 21, the left end cover 22a, and the right end cover 22b form a second cavity 27. The motor assembly 3 and the hydraulic pump assembly 4 are housed in the second cavity 27. The motor assembly 3 and the hydraulic pump assembly 4 share the drive housing 21 and the main shaft 26. The right end cover 22b is connected to the valve assembly 5 and is connected to the valve assembly 5 through an oil outlet 25. The left end cover 22a is provided with an oil passage 24 to connect the second cavity 27 with the first cavity 11. The main shaft 26 is supported on the left end cover 22a and the right end cover 22b through bearings 23.

[0064] The motor assembly 3 includes a stator assembly 31 and a rotor assembly 32, with a certain air gap maintained between the stator assembly 31 and the rotor assembly 32 to ensure that the motor has a reasonable power factor and starting performance during operation. Alternatively, this air gap can be filled with low-pressure cooling oil in the second cavity 27 of the drive housing to dissipate heat from the stator assembly 31 and the rotor assembly 32 of the motor.

[0065] It should be noted that the motor assembly includes, but is not limited to, induction asynchronous motors, permanent magnet DC motors, and permanent magnet synchronous motors. Preferably, the motor assembly is a permanent magnet synchronous motor, and the rotor assembly 32 of the motor assembly includes at least a permanent magnet 33 connected to the outer peripheral surface of the drum 34. In another preferred embodiment, the motor is an induction asynchronous motor, including existing squirrel-cage asynchronous motors and wound-rotor asynchronous motors. The motor assembly includes a stator assembly 31 and a rotor assembly 32. The stator assembly 31 includes components such as a stator core and stator windings. The stator core is a component of the motor's magnetic circuit and electrical circuit, and is formed by stamping and stacking thin silicon steel sheets coated with insulating varnish. Its outer peripheral surface is fixedly connected to the drive housing 21. The stator windings are wound with insulated copper wire or insulated aluminum wire, and the lead-out ends of the stator windings are led to lead-out holes provided on the drive housing 21 and connected to the control assembly 7.

[0066] The hydraulic pump assembly 4 includes a distribution pair, a sliding plate pair, and a plunger pair. The distribution pair includes the end of the cylinder 41 and the distribution plate 42. The sliding plate pair includes the sliding plate 45 and the swashplate 46. The plunger pair includes the plunger 43 and the cylinder bore wall. The stator assembly 31 is fixed on the drive housing 21. The rotor assembly 32 is connected to the cylinder 41 through the rotating drum 34 and supported on the main shaft 26. Under the action of electromagnetic force, the rotor assembly 32 drives the rotating drum 34 and the cylinder 41 of the hydraulic pump assembly to rotate synchronously. The high-pressure oil output by the hydraulic pump assembly enters the valve assembly 5 through the high-pressure oil distribution groove 461 of the swashplate.

[0067] Specifically, the sliding plate pair includes a swashplate 46 and a sliding plate 45 supported on the swashplate 46. The sliding plate 45 is an integral structure, and a hydrostatic oil film support is formed between the sliding plate 45 and the swashplate 46. The distribution pair includes the end of the cylinder body 41 and a distribution plate 42. The cylinder body 41 abuts against the distribution plate 42, and a hydrostatic oil film support is formed between the two. The spindle axis of the main shaft 26 coincides with the cylinder axis of the cylinder body 41. The cylinder body 41 is supported on the main shaft 26 and is connected to the main shaft 26 by a key to achieve synchronous rotation. The plunger pair includes the plunger bore wall of the cylinder body 41 and the plunger 43. The head of the plunger 43 is connected to the sliding plate 45 through a pressure plate 44. Preferably, the plunger 43 is a conical structure with a large-diameter plunger center hole 431 at the center. The plunger 43 reciprocates within the plunger bore 411 of the cylinder body 41 to achieve oil suction and discharge. This invention employs an integral sliding disc structure and a conical plunger structure. The unique design of both significantly reduces the lateral force exerted by the plunger on the cylinder, significantly improves the working conditions of the three major friction pairs, and enhances the stability of the oil film. This enables the hydraulic pump assembly to have higher speed and longer service life to match the working conditions of high-speed motors.

[0068] like Figures 5 to 6 As shown, the sliding plate pair includes a sliding plate 45 and a swashplate 46 supported on the right end cover 33. The sliding plate hydrostatic support surface 451 of the sliding plate 45 is supported on the swashplate 46 and maintains a tight fit with the support surface of the swashplate 46. One end of the sliding plate 45 is provided with a plurality of sliding plate waist-shaped holes 453, and the other end face of the sliding plate 45 is provided with a plurality of plunger ball sockets 458. The sliding plate waist-shaped holes 453 on the sliding plate 45 extend to the plunger ball sockets 458. A swashplate high-pressure distribution groove 461 is provided on the swashplate 46, and the swashplate high-pressure distribution groove 461 is connected to the oil outlet 25 provided on the right end cover 22b.

[0069] A hydrostatic support surface 451 for the sliding plate 45 is provided on the end face opposite to the swashplate 46, such as... Figure 4 As shown, the axis of the slide plate is at a certain angle to the axis of the main shaft. The slide plate hydrostatic support surface 451 is supported on the swashplate 46 and always maintains a sliding fit with the swashplate 46. The slide plate hydrostatic support surface 451 is provided with a plurality of waist-shaped slide plate waist holes 453. Preferably, the slide plate waist holes 453 are evenly distributed on the slide plate hydrostatic support surface 451 with the slide plate axis as the center. The slide plate waist holes 453 are connected to the plunger ball socket 458.

[0070] On the end face of the slide plate 45 opposite to the swash plate 46, there is a protruding slide plate boss surface 452 extending along the axis of the slide plate towards one side of the swash plate 46. The slide plate boss surface 452 is formed by an area enclosed by an inner diameter R1 and an outer diameter R2. The slide plate boss surface 452 and the support surface of the swash plate 46 are in slidable contact with each other. On the slide plate boss surface 452, there are a plurality of slide plate waist-shaped holes 453 at positions corresponding to the plunger ball socket 458. Preferably, the slide plate waist-shaped holes 453 are evenly distributed on the slide plate boss surface 452 with a common circumference centered on the axis of the slide plate.

[0071] An effective hydrostatic oil film support is formed between the slide plate boss surface 452 and the swashplate 46 support surface. A sealing portion for sealing the oil is provided on the slide plate boss surface 452. The sealing portion is disposed around the inner and outer circumferences of the slide plate waist-shaped hole 453. The sealing portion includes an inner slide plate sealing portion 455, an outer slide plate sealing portion 454 distributed radially inside and outside the slide plate waist-shaped hole 453, and a slide plate spacer sealing portion 456 distributed between adjacent slide plate waist-shaped holes 453. The sealing part 455 is the area enclosed by the inner edge of the slide plate waist-shaped hole 453 and the inner diameter R1 of the slide plate boss surface 452. The outer sealing part 454 of the slide plate is the area enclosed by the outer edge of the slide plate waist-shaped hole 453 and the outer diameter R2 of the slide plate boss surface 452. The slide plate interval sealing part 456 is the interval boss surface area between adjacent slide plate waist-shaped holes 453. The sealing part of the slide plate boss surface 452 and the support surface of the swashplate 46 always maintain a certain reasonable gap so that the oil film leakage is at a reasonable level.

[0072] The distribution pair includes the end of the cylinder block 41 and the distribution plate 42. The end face of the cylinder block 41 opposite to the distribution plate 42 is provided with a cylinder block hydrostatic support surface. The cylinder block hydrostatic support surface is supported on the distribution plate 42 and maintains a sliding fit with the support surface of the distribution plate 42. The distribution plate 42 is provided with a low-pressure distribution port 421.

[0073] The outer periphery of the cylinder body 41 is connected to the rotor assembly 32 of the motor assembly. The rotor assembly 32 includes a permanent magnet 33 and a rotating cylinder 34. The permanent magnet 33 is connected to the rotating cylinder 34, or the permanent magnet 33 is nested inside the rotating cylinder 34. The inner side of the rotating cylinder 34 is provided with an inwardly extending connecting portion, which is connected to the outer periphery of the cylinder body 41 by a key. Alternatively, the connection between the connecting portion of the rotating cylinder 34 and the cylinder body 41 may also include, but is not limited to, interference fit connection, bolt connection, etc. A predictable structure is that the permanent magnet 33 can be directly connected to the cylinder body 41 without indirect connection through the cylinder barrel.

[0074] Considering the need for initial sealing between the slide plate 45 and the swashplate 46 during startup and the requirement for a certain return force between the slide plate and the plunger during operation, an initial sealing device and a return mechanism 47 are provided between the cylinder block and the slide plate pair. Preferably, in one return structure, a spring preload device is provided between the slide plate 45 and the cylinder block 41. This spring preload device ensures a certain initial contact force between the slide plate pair and the distribution pair, and ensures the return force of the plunger. The return mechanism includes a central spring, a retaining ring, and a ball joint. One end of the preload spring force of the central spring acts on the slide plate 45 through the ball joint, and the other end acts on the cylinder block end and the distribution plate 42 through the retaining ring.

[0075] A support block 48 is provided in the second cavity 27. One end of the support block 48 is connected to the left end cover 22a, and the other end face of the support block 48 is used to support the distribution plate 42. The support block 48 is provided with a radial oil inlet 481, a transverse oil inlet 482, and a third cavity 483. Figure 7 The diagram shows the internal fluid flow of the power unit in an electro-hydraulic actuator. Taking the piston rod extension as an example, the fluid flow path during the engineering process is explained. During operation, low-pressure cold oil enters the second cavity 27 from the first cavity 11 of the unit housing through the oil passage 24 on the left end cover 22a. The oil in the second cavity 27 enters the third cavity 483 through the radial inlet 481. The oil in the third cavity 483 enters the plunger hole 411 through the transverse inlet 482 and the low-pressure distribution port 421 on the distribution plate 42. After being acted upon by the hydraulic pump assembly, the high-pressure oil flows through the plunger center hole 431 and the sliding... The oil is delivered to the internal oil passage of the valve assembly 5 through the disc-shaped hole 453, the slanted plate distribution groove 461, and the oil outlet 25 on the right end cover 22b. The reversing valve 51 is in the left position. The high-pressure oil is delivered to the rodless chamber 88 through the inlet and outlet ports 52 of the valve block. The return oil from the rod chamber 87 returns to the first cavity 11 or the second cavity 27 through the inlet and outlet ports 52 of the valve assembly 5, or the return oil from the rod chamber 87 returns directly to the first cavity 11 or the second cavity 27.

[0076] The first cavity 11 is also equipped with an oil balancing component 6, which includes a container cavity 61, an elastic container 62, and a valve assembly 63. The container cavity 61 is filled with nitrogen gas at a certain pressure, which is set to a low pressure not exceeding 4 MPa. The valve assembly 63 is installed on the unit housing 1. The pressure in the container cavity 61 changes with the volume and pressure of the oil in the first cavity 11, thus balancing the flow imbalance of oil entering and leaving the first cavity 11. Simultaneously, the oil balancing component 6 in the first cavity 11 of the unit housing also serves the following purposes: First, it allows for an integrated, sealed enclosure of the unit housing 1, resulting in a simple and aesthetically pleasing structure and reduced oil leakage, thus exhibiting environmental friendliness. Second, because the first cavity 11 has a certain pressure, the hydraulic pump assembly inlet maintains a certain pressure for oil intake, preventing cavitation and increasing self-priming capacity and speed. Third, the sealed housing prevents contact with external air and moisture, preventing oil contamination and deterioration, which is beneficial for improving oil service life and performance.

[0077] From the above analysis, it can be seen that since the stator assembly 31 and rotor assembly 32 are completely immersed in the oil in the first cavity 11 and / or the second cavity 27, they have self-cooling characteristics. This is manifested in two ways: firstly, the heat generated by the stator assembly 31 and rotor assembly 32 is conducted to the oil, and dissipated by participating in the system oil circulation; secondly, the heat conducted to the oil by the stator assembly and rotor assembly is dissipated through the heat dissipation and cooling device 12 installed in the unit housing 1. Therefore, this structure has the characteristics of self-cooling and easy heat dissipation, which can prevent the motor stator and rotor from burning out and damage and failure caused by thermal deformation of the three major friction pairs.

[0078] Meanwhile, comparative analysis with existing structures reveals that the electro-hydraulic integrated actuator of this invention achieves a high degree of integration of components such as the electric motor, hydraulic pump, oil tank, valve assembly, oil cylinder, and oil balance component, eliminating components such as couplings, oil pipelines, and air-cooling devices. It features a compact structure, light weight, small size, low power loss, and high power density, significantly reducing the space occupied by the power unit and the amount of hydraulic oil used. The overall structure has the advantages of integration, modularity, and ultra-high power density, making it easy to carry and transport. It can fully utilize the high power-to-weight ratio of hydraulic power, making it particularly suitable for fields with strict requirements on space and weight, such as distributed hydraulic actuator systems in engineering machinery and aerospace, solving a series of problems caused by traditional centralized hydraulic actuator systems, such as long pipelines, large weight, and high energy consumption.

[0079] Meanwhile, this invention houses components that are prone to generating noise, such as the motor assembly 3 and the hydraulic pump assembly 4, inside a common drive housing 21, and then further houses them in a common unit housing 1, where they are encased in oil. Through this layered nesting and oil immersion, the noise and vibration generated by the power unit of the electro-hydraulic actuator are significantly reduced. In addition, the coaxial and housing design of the motor assembly 3 and the hydraulic pump assembly 4, along with the elimination of the air-cooling device, eliminates the noise caused by the different axiality of the mechanical connection and air cooling. Therefore, it is particularly suitable for applications with strict noise and vibration requirements.

[0080] Example 2

[0081] like Figure 8 As shown, this embodiment proposes an open system structure formed by an electro-hydraulic integrated power unit. The difference from Embodiment 1 is that the end cap 22 and valve block 50 of the electro-hydraulic integrated component 2 have different structures. Other structures can be referred to the structure described in Embodiment 1.

[0082] Specifically, the electro-hydraulic integrated assembly 2 includes a drive housing 21, a left end cover 22a, a motor assembly 3, a hydraulic pump assembly 4, and a spindle 26. The drive housing 21 is connected to the valve assembly 5. The drive housing 21, the left end cover 22a, and the valve assembly 5 form a second cavity 27. The motor assembly 3 and the hydraulic pump assembly 4 are housed in the second cavity 27. The motor assembly 3 and the hydraulic pump assembly 4 share the drive housing 21 and the spindle 26. The hydraulic pump assembly 4 is directly connected to the valve assembly 5 through a swashplate high-pressure oil distribution groove 461. An oil passage 24 is provided on the left end cover 22a to connect the second cavity 27 with the first cavity 11. The spindle 26 is supported on the left end cover 22a and the valve assembly 5 through a bearing 23.

[0083] As can be seen from the above structure, integrating the functions of the end cap 22 structure onto the valve block 50 makes the structure more compact and the internal oil passages simpler, further improving the integration and power density of the electro-hydraulic integrated power unit.

[0084] In addition, such as Figure 8 As shown, in some embodiments, an impeller device 210 may be provided on the main shaft 26 of the hydraulic pump assembly 4. The impeller device 210 is provided in the third cavity 483 to enhance the inlet pressure of the hydraulic pump assembly and the circulation of oil in the cavity, thereby improving the self-priming ability and heat dissipation ability of the hydraulic pump assembly.

[0085] Example 3

[0086] like Figure 9 As shown, this embodiment proposes another open system structure composed of an electro-hydraulic integrated power unit. The difference from Embodiment 1 is the structure and positioning of the hydraulic pump assembly 4. Other aspects can be referred to the structure described in Embodiment 1.

[0087] The hydraulic pump assembly 4 includes a distribution pair and a sliding plate pair. The distribution pair of the hydraulic pump assembly is supported on one end face of the support block 48. The other end of the support block 48 is connected to the left end cover 22a. The support block 48 is provided with a radial oil inlet 481, a transverse oil inlet 482, and a third cavity 483. The hydraulic pump assembly 4 receives low-pressure oil from both the distribution pair and the sliding plate pair, and receives high-pressure oil from a single path from the distribution pair. The first cavity 11 is connected to the second cavity 27 through the oil passage 24. The second cavity 27 is connected to the third cavity 483 through the radial oil inlet 481. During operation, the oil enters the plunger hole 411 from the third cavity 483 and / or the second cavity 27 through the distribution pair and the sliding plate pair. The high-pressure oil under the action of the hydraulic pump assembly 4 is transported to the valve assembly 5 through the distribution pair. The reversing valve 53 is used to control the extension and retraction of the piston rod 82. The first cavity 11 or the second cavity 27 receives the return oil.

[0088] Predictably, the positions of the flow distribution pair and the sliding plate pair of the hydraulic pump assembly 4 can be interchanged. That is, the flow distribution pair is placed on the left end cover side, and the sliding plate pair is placed on the valve block 50 side. Therefore, the hydraulic pump assembly 4 has dual low-pressure oil inlets from the flow distribution pair and the sliding plate pair, and single high-pressure oil outlets from the sliding plate pair. The first cavity 11 is connected to the second cavity 27 through the oil passage 24, and the second cavity 27 is connected to the third cavity 483 through the radial oil inlet 481. During operation, low-pressure oil enters the plunger hole 411 from the third cavity 483 and / or the second cavity 27 through the flow distribution pair and the sliding plate pair. The high-pressure oil under the action of the hydraulic pump assembly 4 is transported to the valve assembly 5 through the sliding plate pair. The reversing valve 53 is used to control the extension and retraction of the piston rod 82, and the first cavity 11 or the second cavity 27 receives the return oil.

[0089] Example 4

[0090] like Figure 10 As shown, this embodiment discloses another open system structure composed of an electro-hydraulic integrated power unit. The difference from embodiments 1 and 2 is that the hydraulic pump assembly 4 is set as a double swashplate opposing structure. Other structures can be referred to the structure described in embodiment 1.

[0091] The hydraulic pump assembly 4 has a double-row opposed structure, including a cylinder 41 with multiple through holes, plungers 43, sliding plates 45, and swashplates 46 arranged opposite each other on both sides of the cylinder 41. Each of the left and right swashplates 46 has a second swashplate oil distribution groove 462 opening towards the second cavity 27. The right swashplate 46 also has a first swashplate oil distribution groove 461 connecting to the valve assembly 5. During operation, low-pressure oil from the first cavity 11 enters the second cavity 27 through the oil passage 24. Oil from the second cavity 27 enters the plunger hole 411 from the second swashplate distribution groove 462, the plunger center hole 431, and the sliding plate waist-shaped hole 453. High-pressure oil enters the valve assembly 5 from the plunger center hole 431, the sliding plate waist-shaped hole 453, and the first swashplate oil distribution groove 461.

[0092] Example 5

[0093] like Figures 11 to 14 The diagram shows a preferred embodiment of the electro-hydraulic actuator of the present invention. In this preferred embodiment, the electro-hydraulic actuator is a highly integrated closed system, including a hydraulic cylinder assembly 8 for driving the load and an electro-hydraulic power unit 9 for providing hydraulic power. The electro-hydraulic power unit 9 includes a unit housing 1, an electro-hydraulic assembly 2, a valve assembly 5, and an oil balance assembly 6. One end of the unit housing 1 is connected to the valve assembly 3 to form a closed first cavity 11. The electro-hydraulic assembly 2 and the oil balance assembly 6 are housed in the first cavity 11 and submerged in oil. The electro-hydraulic assembly 2 includes a drive housing 21, an end cap 22, a motor assembly 3, and a hydraulic pump assembly 4. The electro-hydraulic assembly 2 is connected to the valve assembly 5. The drive housing 21 and the end cap 22 form a second cavity 27. The motor assembly 3 and the hydraulic pump assembly 4 are housed in the second cavity 27. The motor assembly 3 and the hydraulic pump assembly 4 share the drive housing 21 and the main shaft 26. The second cavity 27 is connected to the first cavity 11 through an oil passage 24. The motor assembly 3 is configured to operate in both directions with variable speed or constant speed, the hydraulic pump assembly 4 is configured to discharge oil in both directions, and the oil balance assembly 6 is used to balance the imbalance of oil inflow and outflow and provide a certain pressure.

[0094] like Figure 14 This is a schematic diagram of the hydraulic system of the electro-hydraulic integrated actuator. The hydraulic system of the electro-hydraulic integrated actuator is a closed system. The hydraulic pump assembly 4 achieves reversal by changing the direction of the motor assembly 3. The valve assembly 5 includes a valve block 50, a working interface 52, a first relief valve 53, a second relief valve 54, a first hydraulically controlled check valve 56, a second hydraulically controlled check valve 57, and a solenoid unloading valve 55. The first relief valve 53 and the second relief valve 54 are respectively connected to the inlet oil circuit and the return oil circuit in the corresponding two directions to form an overflow circuit. The first hydraulically controlled check valve 56 and the second hydraulically controlled check valve 57... The inlet of the control check valve 57 is connected to the cavity of the unit housing, and the outlet is connected to the corresponding working chamber. The hydraulic control port of the first hydraulic check valve 56 is connected to the oil circuit of the second hydraulic check valve 57, and the hydraulic control port of the second hydraulic check valve 57 is connected to the oil circuit of the first hydraulic check valve 56. The electromagnetic unloading valve 55 is connected to the inlet oil circuit and the return oil circuit to form a bypass oil circuit, which is used to return the high-pressure oil to the hydraulic pump assembly in case of failure, thus playing a safety isolation role. The oil balancing assembly 6 is used to balance the imbalance of oil inflow and outflow and provide a certain replenishment pressure. As can be predicted, as can be easily extended by those skilled in the art, the valve assembly 5 can include one or a combination of various existing flow valves and pressure valves used to control the speed and direction of oil, such as balance valves or safety valves, to maintain the stability of load reduction or the safety of load operation. It should be noted that this embodiment relies on the speed change of the motor assembly for volume speed regulation, and the oil direction is changed by changing the rotation direction of the motor assembly.

[0095] In this embodiment, the swashplate is a bidirectional high-low pressure distribution structure. When the piston rod extends, the high-pressure oil formed by the hydraulic pump assembly passes through the plunger center hole 431, the swashplate waist-shaped hole 453, the first swashplate distribution groove 461, and the first oil port 25 and is delivered to the rodless chamber 88 of the actuator via the valve assembly 5, driving the piston to extend outward. The return oil from the rod chamber 87 of the actuator passes through the valve assembly 5 and returns to the plunger hole 411 via the second oil port 29, the second swashplate distribution groove 462, the swashplate waist-shaped hole 453, and the plunger center hole 431. When the piston rod retracts, the high-pressure oil formed by the hydraulic pump assembly passes through the plunger center hole 431, the swash plate waist-shaped hole 453, the second swash plate distribution groove 462, and the second oil port 29 and is delivered to the rod chamber 87 of the actuator via the valve assembly 5. Part of the oil returning from the rodless chamber 88 of the actuator passes through the valve assembly 5 through the first oil port 25, the first swash plate distribution groove 461, the swash plate waist-shaped hole 453, and the plunger center hole 431 back to the plunger hole 411. The other part of the oil returning flows back to the first cavity 11 through the hydraulic control check valve. The oil balance assembly 6 works in conjunction with the first hydraulic control check valve 56 and the second hydraulic control check valve 57 to replenish oil and stabilize oil pressure.

[0096] Example 6

[0097] like Figure 14 As shown, this embodiment provides another closed system structure composed of an electro-hydraulic integrated power unit. The difference from embodiment 5 is that the structure and setting position of the hydraulic pump assembly 4 are different. Other aspects can be referred to the structure described in embodiment 5.

[0098] Specifically, the hydraulic pump assembly 4 includes a cylinder block 41, a distribution plate 42, a plunger 43, a sliding plate 45, and a swashplate 46. The sliding plate 45 is located on one side of the left end cover 22a and is supported on the swashplate 46 by a hydrostatic oil film. The distribution plate 42 is located on the side close to the valve assembly 5. A distribution block 49 is provided between the distribution plate and the valve block 50. The distribution block 49 is supported on the valve block 50. The distribution block 49 is provided with a first distribution groove 491 and a second distribution groove 492. The first distribution groove 491 and the second distribution groove 492 are respectively connected to the distribution port of the distribution plate and the oil port of the valve block. The high-pressure oil formed after the action of the hydraulic pump assembly is transported to the internal oil passage of the valve block 50 through the distribution port of the distribution plate, the first distribution groove 491, or the second distribution groove 492.

[0099] The distribution plate is a bidirectional high and low pressure distribution structure. When the actuator piston rod extends, the high-pressure oil formed by the hydraulic pump assembly passes through the first distribution port 421 of the distribution plate, the first distribution groove 491 of the distribution block, and the valve assembly 5 to the rodless chamber 88 of the actuator. The return oil from the rod chamber 87 of the actuator returns to the plunger hole 411 through the valve assembly 5, the second distribution groove 492 of the distribution block, and the second distribution port 422 of the distribution plate. When the actuator piston rod retracts, the high-pressure oil formed by the hydraulic pump assembly passes through the second distribution port 422 of the distribution plate, the second distribution groove 492 of the distribution block, and the valve assembly 5 to the rod chamber 87 of the actuator. The return oil from the rodless chamber 88 of the actuator returns to the plunger hole 411 through the valve assembly 5, the first distribution groove 491, and the first distribution port 421 of the distribution plate. The oil balance assembly 6 works in conjunction with the first hydraulic control check valve 56 and the second hydraulic control check valve 57 to replenish oil and stabilize oil pressure.

[0100] Example 7

[0101] like Figure 10 As shown, this embodiment provides another closed system structure composed of an electro-hydraulic integrated power unit. The difference from embodiment 5 is that the hydraulic power unit is equipped with a heat dissipation and cooling device 12. Other structures can be referred to in embodiment 1 or 5.

[0102] A preferred heat dissipation and cooling device is to provide heat sinks 13 on the unit housing 1. The heat dissipation area of ​​the heat sinks 13 is much larger than the surface area of ​​the unit housing, so that the heat of the oil in the unit housing can be quickly dissipated to the outside air through the heat sinks.

[0103] Another preferred heat dissipation and cooling device is a water-cooled method, which includes a cooling water inlet 14, a cooling water outlet 15, and a cooling channel 16 on the unit housing 1. Cooling water enters the cooling channel 16 through the cooling water inlet 14, takes away the heat of the oil in the first cavity inside the unit housing, and flows out through the cooling water outlet 15 to achieve forced cooling of the power unit.

[0104] It can be predicted that the heat dissipation and cooling device of the present invention includes, but is not limited to, natural heat dissipation by heat sinks and one or more combinations of forced cooling by air cooling, water cooling, and oil cooling.

[0105] Therefore, compared with existing power units, the electro-hydraulic integrated power unit of this embodiment has a significant heat dissipation and cooling effect, specifically in the following ways: First, the electro-hydraulic integrated component 2 is wrapped in oil, which can achieve rapid heat transfer and prevent heat from accumulating inside, causing the motor component and hydraulic pump component to overheat and burn out or reduce performance; Second, heat sinks or a forced circulation cooling system are set on the outside of the unit housing 1, which can quickly remove the hot oil inside the unit housing, so that this electro-hydraulic integrated power unit can operate continuously and at high power.

[0106] Example 8

[0107] like Figure 16 As shown, this embodiment provides another closed system structure composed of an electro-hydraulic integrated power unit. The difference from embodiment 5 is that the valve block 50 and the connecting block 85 of the electro-hydraulic integrated actuator are an integral structure. Other structures can be referred to in embodiment 1 or 5.

[0108] The valve block 50 and the connecting block 85 are set as an integral structure. The integral valve block 50 is connected to the cylinder 81 and closes the opening on one side of the cylinder 81. The integral valve block 50 integrates a control valve. The integral valve block structure is more convenient to manufacture, and the integration and modularity are further improved.

[0109] When implemented according to the above case, the following results can be achieved:

[0110] (1) The electro-hydraulic integrated actuator of the present invention integrates the electric motor, hydraulic pump, oil tank, oil balance component and cylinder assembly, eliminating components such as coupling, oil pipeline and air cooling device. It has the characteristics of compact structure, light weight, small size, low power loss and high power density, which significantly reduces the space occupied by the actuator and significantly reduces the amount of hydraulic oil used. The overall structure has the advantages of integration, modularity and ultra-high power density, which is easy to install and can give full play to the high power-to-weight ratio of hydraulic power. It is especially suitable for fields with strict requirements on space and weight. For example, it can be matched with distributed hydraulic actuator systems in the fields of engineering machinery, aerospace and robotics, and solve a series of problems such as long pipeline, large weight and high energy consumption brought about by traditional centralized hydraulic actuator systems.

[0111] (2) The electro-hydraulic actuator of the present invention accommodates the motor assembly, hydraulic pump assembly and other components that are prone to generating noise in a common housing and then accommodates them in a common housing unit and is wrapped in oil. Through the layer nesting and oil immersion, the noise and vibration generated by the actuator are significantly reduced. In addition, the coaxial and housing design of the motor assembly and hydraulic pump assembly and the elimination of the air cooling device eliminate the noise caused by the different axiality of the mechanical connection and air cooling. Therefore, it is particularly suitable for occasions with strict noise and vibration requirements.

[0112] (3) The electro-hydraulic actuator of the present invention adopts an integrated sealed package. On the one hand, there are fewer external pipelines and interfaces, and less oil leakage, thus having environmentally friendly characteristics; on the other hand, the sealed shell can prevent contact with external air and moisture, prevent oil pollution and deterioration, and help improve the service life and performance of the oil.

[0113] (4) The electro-hydraulic integrated actuator of the present invention has good thermal stability, especially the open electro-hydraulic integrated actuator, which has more outstanding thermal stability. This is mainly reflected in the following aspects: First, the internal oil of the electro-hydraulic integrated component can be circulated into the hydraulic system through double-end oil distribution, so as to achieve oil self-cooling; Second, the electro-hydraulic integrated component is wrapped in oil, which can achieve rapid heat transfer and prevent heat from accumulating inside, which would cause the motor component and hydraulic pump component to overheat and burn out or reduce performance; Third, heat sinks or forced circulation cooling system are set on the outside of the unit housing, which can quickly remove the hot oil inside the unit housing; Therefore, the electro-hydraulic integrated power unit can operate continuously and at high power.

[0114] (5) In the electro-hydraulic integrated actuator of the present invention, the hydraulic pump assembly adopts an integral sliding plate structure and a conical plunger structure. The unique design of the two significantly reduces the lateral force of the plunger acting on the cylinder, significantly improves the working conditions of the three major friction pairs, and improves the stability of the oil film, so that the hydraulic pump assembly has higher speed and longer service life to match the working conditions of high-speed motor.

[0115] (6) The open electro-hydraulic actuator of the present invention relies on the unidirectional speed change of the motor assembly for volumetric speed regulation and realizes the reversing of the oil through the reversing valve. This structure can significantly reduce the overall cost on the one hand, and avoid motor damage caused by repeated high-frequency reversing under high-speed conditions with high rotational inertia on the other hand.

[0116] The above description, in conjunction with specific preferred technical solutions, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention. All technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A radially integrated power unit, characterized in that: The system includes a tank unit for containing hydraulic oil, and an electro-hydraulic integrated assembly is installed inside the tank unit. The electro-hydraulic integrated assembly includes a drive housing that connects to the inner cavity of the tank unit. A hydraulic pump assembly and a motor assembly that rotate synchronously are coaxially nested along the radial direction inside the drive housing. The hydraulic pump assembly includes a main shaft, a sliding plate pair, a plunger pair, and a flow distribution pair. The sliding plate pair includes a swashplate and a sliding plate supported on the swashplate and having an integral disc structure. The sliding plate pair or the flow distribution pair connects to the plunger pair to form an oil passage and cooperates with the plunger pair to perform oil suction and oil pressure. Alternatively, both the flow distribution pair and the sliding plate pair connect to the plunger pair to form an oil passage and cooperate with the plunger pair to perform oil suction and oil pressure. The motor assembly includes a rotor structure that cooperates with and rotates coaxially with a plunger pair, and a stator structure disposed within a drive housing. A rotational gap is formed between the rotor structure and the stator structure and is filled with oil. The oil tank unit includes a unit housing and a valve assembly. The valve assembly includes a valve block that is connected and cooperates with the unit housing. The valve block is provided with a control valve group for controlling the direction, and / or flow rate, and / or pressure of the hydraulic oil.

2. The radial integrated power unit according to claim 1, characterized in that: The oil tank unit is equipped with an oil balance component, which includes an elastic container filled with gas and completely submerged in hydraulic oil. The elastic container is connected to a gas valve assembly for venting.

3. The radial integrated power unit according to claim 1, characterized in that: The drive housing is connected to a detachable end cap to form a sealed cylindrical structure. The two ends of the main shaft are respectively engaged with the two end faces of the cylindrical structure. One end of the cylindrical structure is provided with an oil passage and connects to the inner cavity of the oil tank unit to form an oil inlet path. The other end of the cylindrical structure is provided with an oil outlet and fits against the valve block to form an oil outlet path.

4. The radial integrated power unit according to claim 1, characterized in that: The drive housing forms a cylindrical structure with one end sealed and the other end open. The sealed end of the cylinder is provided with an oil inlet. The open end of the cylinder structure is connected to the valve block to seal the cylinder structure. One end of the main shaft is connected to the sealed end of the cylinder structure, and the other end of the main shaft is connected to the valve block. The sliding plate pair is connected to the valve block to form an oil outlet passage.

5. The radial integrated power unit according to claim 1, characterized in that: The drive housing forms a cylindrical structure with one end sealed and the other end open. The sealed end of the cylinder is provided with an oil inlet, and the open end of the cylinder structure is connected to a valve block to seal the cylinder structure. One end of the main shaft is connected to the sealed end of the cylinder structure, and the other end of the main shaft is connected to the valve block. The oil distribution pair includes a distribution block sleeved on the main shaft. One end of the distribution block is connected to the valve block, and the other end of the distribution block is pressed against the distribution plate. The distribution block and the distribution plate are respectively provided with low-pressure distribution ports and / or high-pressure distribution ports, which are connected to form oil passages. When the plunger pair rotates to connect with the low-pressure distribution port, oil is drawn in; when the plunger pair rotates to connect with the high-pressure distribution port, oil is compressed.

6. The radial integrated power unit according to any one of claims 1 to 4, characterized in that: The oil distribution pair includes a support member sleeved on the main shaft. One end of the support member is connected and fixed to the drive housing, and the other end of the support member is pressed against the oil distribution plate.

7. The radial integrated power unit according to claim 6, characterized in that: The support member has an internal cavity, and the support member is provided with an oil port that connects the cavity and the inner cavity of the drive housing. The oil distribution plate is provided with a low-pressure oil distribution port that connects to the cavity. When the cylinder rotates and connects with the low-pressure oil distribution port, oil is drawn in.

8. The radial integrated power unit according to claim 1, characterized in that: The slide plate assembly includes a swashplate sleeved on the main shaft, with a mounting surface on the swashplate for tilting the slide plate. The slide plate is sleeved on the main shaft and simultaneously fits against the mounting surface. The slide plate has a plunger ball socket for fitting the plunger end, and the plunger end is slidably embedded in the plunger ball socket by a pressure plate. The plunger ball socket passes through the slide plate through a waist-shaped hole. The swashplate is provided with a high-pressure distribution groove and / or a low-pressure distribution groove. When the cylinder rotates and the waist-shaped hole of the slide plate connects to the high-pressure distribution groove, oil is pumped outward. When the cylinder rotates and the waist-shaped hole of the slide plate connects to the low-pressure distribution groove, oil is drawn in from the outside.

9. The radial integrated power unit according to claim 7, characterized in that: The sliding plate pair is symmetrically arranged on both sides of the plunger pair. Both ends of the plunger pair are provided with plungers that cooperate with the sliding plate pair and reciprocate to both sides to synchronously draw in and press in oil. The swashplate in the sliding plate pair that cooperates with the oil outlet is provided with a swashplate high-pressure distribution groove and a swashplate low-pressure distribution groove for drawing in and pressing in oil. The swashplate in the sliding plate pair away from the oil outlet is provided with a swashplate low-pressure distribution groove for drawing in oil.

10. The radial integrated power unit according to claim 1, characterized in that: The tank unit has a heat dissipation and cooling structure on its housing. The heat dissipation and cooling structure includes heat sinks on the housing or a circulating cooling assembly on the housing. The circulating cooling assembly includes a circulating cooling channel surrounding the housing, and the circulating cooling channel has a circulating medium inlet and a circulating medium outlet.

11. An electro-hydraulic actuator, employing the power unit according to any one of claims 1 to 10, characterized in that: The power unit is connected to the hydraulic cylinder assembly that drives the load via a valve block. The hydraulic cylinder assembly includes a cylinder barrel, a piston rod is provided inside the cylinder barrel and the piston rod divides the cylinder barrel into two action chambers. Each action chamber is provided with an oil port. Two oil ports on the valve block are respectively connected to the oil ports of the two action chambers and controlled by a control valve. The front end of the piston rod is provided with a drive connection structure for connecting and driving the load. The hydraulic cylinder assembly includes an asymmetrical single rod or a symmetrical double rod structure.

12. Application of the electro-hydraulic actuator, applicable to the electro-hydraulic actuator of claim 11, characterized in that: The electro-hydraulic actuator constitutes a one-way open system. The motor assembly operates in one direction. The control valve group includes at least one directional valve, one relief valve, and one check valve. The working port of the directional valve is connected to the two chambers of the actuator. The oil inlet of the directional valve is connected to the outlet of the hydraulic pump assembly. The inlet of the relief valve is connected to the outlet of the hydraulic pump assembly. The outlet of the relief valve is connected to the inner cavity of the drive housing. High-pressure oil is supplied to the actuator from the output of the hydraulic pump assembly. The inner cavity of the drive housing receives the return oil from the actuator.

13. Application of the electro-hydraulic actuator, applicable to the electro-hydraulic actuator of claim 11, characterized in that: The electro-hydraulic actuator constitutes a closed system. The motor assembly and the hydraulic pump assembly can operate in both directions. High-pressure oil is output from the hydraulic pump assembly, delivered to the actuator via the valve block, and then returned to the hydraulic pump assembly via the valve block. The valve block is equipped with a control valve group, which includes at least two relief valves, two replenishing check valves, and one electromagnetic unloading valve connected to the main oil circuit. The control valve group can also be equipped with a balance valve or a hydraulically controlled check valve as needed.

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