High-power low-speed high-torque electro-hydraulic drive system

Abstract

The present invention discloses a high-power low-speed high-torque electro-hydraulic drive system, which includes a hydraulic motor assembly, an oil tank, and an electro-hydraulic integrated machine assembly accommodated in the cavity of the oil tank housing. The electro-hydraulic integrated machine assembly includes a motor housing assembly, and a rotor assembly, a stator assembly, and a hydraulic pump assembly accommodated in the housing cavity of the motor housing assembly. The hydraulic motor assembly is connected to the oil tank housing. The hydraulic pump assembly outputs high-pressure hydraulic oil to the hydraulic motor assembly under the drive of electromagnetic force, driving the hydraulic motor assembly to work, and realizing the conversion from electrical energy to hydraulic energy and then to mechanical energy. The drive system of the present invention has a high degree of electro-hydraulic integration, and has the characteristics of large power, compact structure, small volume, light weight, stepless speed changeability, convenient variable, low noise, high efficiency and energy saving, self-cooling, high power density, high reliability, long service life, etc.

Description

Technical Field

[0001] The present invention belongs to the field of power transmission and control, and particularly relates to a high-power low-speed large-torque electro-hydraulic drive system. Background Art

[0002] Low-speed large-torque drive systems have extremely broad application prospects in industrial production, oilfield exploitation, mining machinery, construction machinery, building machinery, coal mining machinery, metallurgical machinery, water conservancy, ocean engineering, port hoisting, ship propulsion, aerospace and other fields. As Figure 1 shown, the current traditional low-speed large-torque drive system includes a mechanical reduction mechanism 1, an electric motor 2, a coupling 3, a cooling device 4, and a load system 7. The electric motor 2 outputs torque at high speed. Through the transmission chain of the coupling 3 and the mechanical reduction mechanism 1, after the speed is reduced and the torque is increased, the load system 7 is driven to work. The cooling device 4 cools the electric motor to prevent the electric motor 2 from burning out due to excessive temperature. This structure has the following characteristics: (1) The mechanical reduction mechanism 1, the coupling 3, and the electric motor 2 are arranged axially, which occupies a large space, has a heavy weight, and a low power density, which is particularly disadvantageous for occasions where space and weight are limited; (2) The transmission structure is complex, and there are many energy conversion and power transmission links. It is not easy to ensure the coaxiality during assembly, and mechanical friction losses, vibration and noise are likely to occur; (3) The reduction mechanism has difficulties in processing, high prices, poor operating reliability, high failure rates, is prone to failures, and has high maintenance costs; (4) The overall efficiency of the system is low, and additional cooling and lubrication devices need to be added, increasing the complexity of the equipment, additional energy losses, and construction and operation costs, which does not meet the requirements of economic development for energy conservation and environmental protection; (5) The traditional transmission mode has the problem of "fixed speed, fixed mode", and the production mode is difficult to be adjusted accordingly according to the working conditions.

[0003] Another new type of low-speed large-torque drive system - a low-speed large-torque permanent magnet direct drive system is developing rapidly and is favored by various industries. This system includes a permanent magnet direct drive motor and a load system. The permanent magnet direct drive motor is directly connected to the load system, eliminating the mechanical reduction mechanism 1, which significantly reduces the maintenance workload. However, the low-speed large-torque permanent magnet direct drive system also has the following problems: (1) Since a lower speed is required, the number of poles of the permanent magnet direct drive motor is very large, the number of slots is large, and the requirement for high efficiency forces the motor to increase its outer diameter, and the volume and weight of the motor increase significantly; (2) The permanent magnet direct drive motor uses a large amount of materials, especially rare metals (such as neodymium iron boron, cobalt, etc. rare earths), and affected by raw materials, its cost has been high; (3) The permanent magnet direct drive motor needs to add additional electronic components for frequency conversion control. High-power electronic components have high technical requirements and high prices.

[0004] With the development of various equipment towards larger sizes, the demand for high-power equipment is increasing. The power of some large equipment even reaches the MW level, while the requirements for its volume and weight are becoming increasingly strict. This is in line with the law of technological development. Based on this demand, a high-power low-speed large-torque drive system is proposed. Summary of the Invention

[0005] The object of the present invention is to provide a new type of high-power low-speed large-torque drive system with one or more characteristics of high power, compact structure, small volume, light weight, stepless speed change, convenient variable, low noise, high energy efficiency, high power density, high reliability, and long life, aiming at the problems existing in the current traditional low-speed large-torque drive system.

[0006] The implementation mode of the technical solution of the present invention: A high-power low-speed large-torque electro-hydraulic drive system, characterized in that it includes a hydraulic motor assembly, an oil tank, and an electro-hydraulic integrated machine assembly accommodated in the cavity of the oil tank housing. The electro-hydraulic integrated machine assembly includes a motor housing assembly, and a rotor assembly, a stator assembly, and a hydraulic pump assembly accommodated in the housing cavity of the motor housing assembly. The hydraulic motor assembly is connected to the oil tank housing. The hydraulic pump assembly outputs high-pressure oil to the hydraulic motor assembly under the drive of electromagnetic force, driving the hydraulic motor assembly to work, realizing the conversion from electrical energy to hydraulic energy and then to mechanical energy.

[0007] In the high-power low-speed large-torque electro-hydraulic drive system of the present invention, the hydraulic pump assembly includes a flow distribution sliding disk pair and a plunger pair. The flow distribution sliding disk pair includes an inclined disk and a sliding disk supported on the inclined disk. The sliding disk is an integral disk-shaped structure, and a static pressure oil film support is formed between the sliding disk and the inclined disk. The plunger pair includes a cylinder block and a plunger.

[0008] In the high-power low-speed large-torque electro-hydraulic drive system of the present invention, the electro-hydraulic integrated machine assembly further includes a main shaft and a rotating cylinder. The main shaft is connected to the cylinder block, and the rotating cylinder is respectively connected to the rotor assembly and the cylinder block, so that the rotating cylinder, the cylinder block, and the rotor assembly rotate synchronously. The cylinder block is accommodated in the rotating cylinder, and the axial hydraulic pressures acting on the cylinder block are balanced or offset from each other.

[0009] In the high-power low-speed large-torque electro-hydraulic drive system of the present invention, the cylinder block is an integral structure. The two ends of the cylinder block have a plurality of plunger holes evenly distributed circumferentially around the central axis of the cylinder block. The plunger holes of the cylinder block are through-hole structures with both ends open.

[0010] In the high-power low-speed large-torque electro-hydraulic drive system of the present invention, the cylinder block is two opposed independent cylinder blocks. The cylinder block has a plurality of plunger holes evenly distributed circumferentially around the central axis of the cylinder block. The plunger holes of the cylinder block are blind hole structures with one end closed and one end open, and the end faces of the cylinder blocks on the opposed sides are closed.

[0011] In the high-power low-speed high-torque electro-hydraulic drive system of the present invention, a spindle connection part protruding outward is circumferentially arranged in the middle of the spindle, a drum connection part protruding inward is circumferentially arranged in the middle of the drum, and the drum is respectively connected to the spindle and the rotor assembly, so that the drum, the spindle, the cylinder block and the rotor assembly rotate synchronously. The axially opposite ends of the cylinder block, which are closed on one side, abut against both ends of the spindle connection part, so that the axial hydraulic pressures acting on the two ends of the cylinder block are balanced with each other.

[0012] In the high-power low-speed high-torque electro-hydraulic drive system of the present invention, the motor housing assembly includes a front end cover, a rear end cover and a motor housing. The swash plate of the flow distribution sliding disk pair on the side close to the hydraulic motor assembly in the hydraulic pump assembly abuts against one end face of the front end cover, the distribution shaft of the hydraulic motor assembly abuts against the other end face of the front end cover, and the distribution shaft is provided with a distribution shaft low-pressure port and a distribution shaft high-pressure port.

[0013] In the high-power low-speed high-torque electro-hydraulic drive system of the present invention, the electro-hydraulic drive system is an open-loop system. The front end cover is provided with a front end cover low-pressure oil inlet passage and a front end cover high-pressure oil passage, the rear end cover is provided with a rear end cover low-pressure oil inlet passage, a rear end cover high-pressure oil passage and a rear end cover low-pressure oil passage. The front end cover high-pressure oil passage is communicated with the distribution shaft high-pressure port. The front end cover low-pressure oil inlet passage, the rear end cover low-pressure oil inlet passage and the distribution shaft low-pressure port respectively open to the cavity of the oil tank housing, so that the oil in the cavity of the oil tank housing enters the cylinder block plunger holes of the hydraulic pump assembly to take away heat and realize self-cooling.

[0014] In the high-power low-speed high-torque electro-hydraulic drive system of the present invention, the electro-hydraulic drive system is a closed-loop system. The front end cover is provided with a front end cover high-pressure oil passage and a front end cover low-pressure oil passage, the rear end cover is provided with a rear end cover low-pressure oil inlet passage, a rear end cover high-pressure oil passage and a rear end cover low-pressure oil passage. The front end cover high-pressure oil passage is communicated with the distribution shaft high-pressure port. The front end cover low-pressure oil passage is respectively communicated with the distribution shaft low-pressure port and the motor housing low-pressure oil passage. After the low-pressure oil enters the hydraulic pump assembly from the rear end cover low-pressure oil inlet passage, the high-pressure oil formed by the action is transported to the hydraulic motor assembly through the front end cover high-pressure oil passage, and the low-pressure oil formed by the action returns to the hydraulic pump assembly through the front end cover low-pressure oil passage to form a closed loop.

[0015] In the high-power low-speed high-torque electro-hydraulic drive system of the present invention, a check valve and / or a makeup oil pump are arranged on the rear end cover. The makeup oil pump is connected to one end of the spindle. The oil outlet of the check valve is communicated with the rear end cover low-pressure oil inlet passage. The check valve and / or the makeup oil pump are used to supplement the oil leakage in the closed loop.

[0016] For the high-power, low-speed, and high-torque electro-hydraulic drive system described in the present invention, a valve group is connected to the oil tank housing or the motor housing. The motor housing is provided with a high-pressure oil passage for the motor housing. The oil inlet of the valve group is communicated with the high-pressure oil passage of the motor housing. The valve group is used for controlling the pressure, flow rate, and direction of the hydraulic pump assembly. The valve group includes one or a combination of a pressure valve, a flow valve, and a direction valve.

[0017] For the high-power, low-speed, and high-torque electro-hydraulic drive system described in the present invention, an accumulator is provided on the electro-hydraulic drive system. The accumulator is connected to the valve group. The accumulator has one or more functions including assisting in starting, stabilizing pressure, supplementing leaked oil, and providing an auxiliary control oil source.

[0018] For the high-power, low-speed, and high-torque electro-hydraulic drive system described in the present invention, the hydraulic pump assembly includes two port plate slide pairs. The swash plates of the port plate slide pairs are respectively abutted against the front end cover and the rear end cover. Among them, the swash plate abutted against the front end cover side is a swash plate with a fixed inclination angle, and the swash plate abutted against the rear end cover side is a variable-angle swash plate.

[0019] For the high-power, low-speed, and high-torque electro-hydraulic drive system described in the present invention, a variable mechanism is provided on the rear end cover. The supporting surface on the swash plate opposite to the rear end cover has a cylindrical sliding arc surface formed. The variable mechanism includes a variable piston, a control valve, and a variable spring. The variable piston drives the swash plate to slide on the cylindrical sliding arc surface to achieve stepless speed change control.

[0020] For the high-power, low-speed, and high-torque electro-hydraulic drive system described in the present invention, the hydraulic pump assembly is of a shaft-supported structure. It also includes a first bearing and a second bearing. The axis of the main shaft coincides with the axis of the cylinder block. One end of the main shaft penetrates through the port plate slide pair at the corresponding end to the front end cover and is supported on the first bearing, and the other end penetrates through the port plate slide pair at the corresponding end to the rear end cover and is supported on the second bearing. The cylinder block is supported on the main shaft and is connected to the main shaft through a key to achieve synchronous rotation. The plunger pair includes the plunger hole wall of the cylinder block and the plunger. The plunger reciprocates in the plunger cavity of the cylinder block to achieve oil suction and discharge work.

[0021] For the high-power, low-speed, and high-torque electro-hydraulic drive system described in the present invention, the hydraulic pump assembly is of a rotating drum-supported structure. It also includes a fourth bearing and a fifth bearing. The fourth bearing and the fifth bearing are respectively clamped between the rotating drum and the motor housing assembly. The rotor assembly and the hydraulic pump assembly are supported on the fourth bearing and the fifth bearing through the rotating drum and achieve synchronous rotation. The plunger pair includes the plunger hole wall of the cylinder block and the plunger. The plunger reciprocates in the plunger cavity of the cylinder block to achieve oil suction and discharge work.

[0022] Based on the above technical solutions, the beneficial effects of the present invention are:

[0023] (1) The present invention significantly reduces the weight and volume of the low-speed high-torque drive system and improves the overall power density of the system. In the present invention, devices such as a hydraulic motor assembly, two hydraulic pump assemblies, an electric motor assembly, control, a fuel tank, an accumulator, etc. are highly integrated into one body, and the mechanical reduction mechanism in the traditional low-speed high-torque drive system is cancelled, giving full play to the high power-to-weight ratio characteristic of hydraulic transmission, so that the overall volume and weight of the power drive system are significantly reduced. Therefore, the low-speed high-torque drive system of the present invention has outstanding high power-to-weight ratio advantages and is particularly suitable for fields with strict requirements on space and weight, such as mobile machinery, ship propulsion systems, and aerospace fields.

[0024] (2) High power and large overall power density. In the present invention, devices such as a hydraulic motor assembly, two hydraulic pump assemblies, an electric motor assembly, control, a fuel tank, an accumulator, etc. are highly integrated into one body, and the two hydraulic pump assemblies and the electric motor assembly are jointly integrated in the motor housing. In the same motor housing space, the output of double high-pressure oil can be realized, which can meet the requirements of a high-power electro-hydraulic drive system.

[0025] (3) The present invention is easy to achieve stepless speed change control. In the present invention, devices such as a hydraulic motor assembly, two hydraulic pump assemblies, an electric motor assembly, control, a fuel tank, an accumulator, etc. are highly integrated into one body, and stepless speed regulation can be achieved by adjusting the swash plate angle, etc. The speed regulation is a soft regulation, which can better adapt to the speed change control under different working conditions, eliminating complex and expensive electronic components such as a frequency converter controller, reducing power loss, and lowering costs.

[0026] (4) The present invention has high transmission efficiency. In the present invention, devices such as a hydraulic motor assembly, two hydraulic pump assemblies, an electric motor assembly, control, a fuel tank, an accumulator, etc. are highly integrated into one body, eliminating components such as the mechanical reduction mechanism, drive shaft, and coupling in the transmission link, eliminating additional electronic components such as a frequency converter controller, and eliminating components such as a cooling device. Therefore, the energy conversion and power transmission links and the additional energy losses of the cooling device and electronic components are reduced. At the same time, the mechanical friction loss is also significantly reduced, making the overall efficiency of the drive system higher and the operation more reliable.

[0027] (5) The present invention significantly reduces noise and vibration. The main sources of noise and vibration in the traditional power drive system are: mechanical reduction mechanism, electric motor, mechanical vibration and noise generated by the coaxiality error of the coupling connection, and noise and vibration generated by the electric motor air-cooling device; in the present invention, devices such as a hydraulic motor assembly, two hydraulic pump assemblies, an electric motor assembly, control, a fuel tank, an accumulator, etc. are highly integrated into one body, the electric motor assembly and the hydraulic pump assembly are coaxial and co-shell, canceling the coupling, air-cooling device, and the connecting pipeline between the hydraulic pump and the hydraulic motor, and the noise is significantly reduced.

[0028] (6) The present invention is self-cooling and easy to dissipate heat. In the operation of traditional motors and mechanical speed reduction mechanisms, there is energy dissipation, which is finally dissipated in the external environment in the form of heat, and additional cooling devices or lubrication devices are required. In the present invention, devices such as a hydraulic motor assembly, two hydraulic pump assemblies, an electric motor assembly, a control unit, an oil tank, and an accumulator are highly integrated. The low-pressure cold oil in the cavity of the housing flows through the three major friction pairs of the motor stator assembly, rotor assembly, and hydraulic pump assembly, and brings the heat generated by them into the hydraulic system to achieve self-cooling.

[0029] (7) The present invention has a long service life and high reliability. The electro-hydraulic drive system in the present invention is highly integrated, and each mechanical component is highly integrated and simplifies the structural complexity; the sliding disk in the flow distribution sliding disk pair is an integral structure, and the plunger in the plunger pair is a conical structure. Their unique designs significantly reduce the lateral force of the plunger acting on the cylinder block, significantly improve the working conditions of the three major friction pairs, and improve the oil film stability, enabling the hydraulic rotor part to have higher speed, higher pressure, larger flow rate, and longer service life.

[0030] (8) The present invention can be easily designed into a closed circuit, which is beneficial to reducing the volume of the oil tank, facilitating the setting of energy storage devices, facilitating the reverse direction transformation, and at the same time improving the operating efficiency of the system.

[0031] (9) The present invention reduces external leakage. The electro-hydraulic of the drive system is highly integrated, avoiding the corrosion and wear of the seals at multiple pipeline connection parts and the shaft extension of the hydraulic pump under long-term working conditions, which may cause external leakage, resulting in environmental pollution and inconvenience in management and maintenance, and is especially suitable for occasions with strict environmental requirements.

[0032] (10) The present invention can achieve multi-machine series-parallel connection. In the present invention, devices such as a hydraulic motor assembly, two hydraulic pump assemblies, an electric motor assembly, a control unit, an oil tank, and an accumulator are highly integrated. It has a large power, small volume, and light weight. When ultra-high power is required, multiple high-power electro-hydraulic drive systems can be connected in series and parallel to achieve a doubling of the output power. Description of the Drawings

[0033] Figure 1 It is a schematic structural diagram of a traditional low-speed high-torque drive system.

[0034] Figure 2 It is a schematic structural diagram of the high-power electro-hydraulic drive system of the present invention.

[0035] Figure 3 It is an embodiment of the open electro-hydraulic drive system in the present invention.

[0036] Figure 4 For Figure 3 The A-A sectional view in

[0037] Figure 5It is the internal liquid flow diagram of the high-power electro-hydraulic drive system in the present invention.

[0038] Figure 6 It is the plan view of one end of the sliding disc in the present invention.

[0039] Figure 7 It is Figure 6 the B-B sectional view of the sliding disc structure in

[0040] Figure 8 It is the plan view of the other end of the sliding disc in the present invention.

[0041] Figure 9 It is a plan view of one supporting surface of the swash plate in the present invention.

[0042] Figure 10 It is a plan view of the other supporting surface of the swash plate in the present invention.

[0043] Figure 11 It is the sectional view of the rotating cylinder along the axis in the present invention.

[0044] Figure 12 It is the plan view of one side of the rotating cylinder in the present invention.

[0045] Figure 13 It is an embodiment of the electro-hydraulic drive system with two cylinders opposed in the present invention.

[0046] Figure 14 It is an embodiment of the closed electro-hydraulic drive system in the present invention.

[0047] Figure 15 It is an embodiment of the rotating cylinder supported electro-hydraulic drive system in the present invention.

[0048] Figure 16 It is another embodiment of the permanent magnet rotor assembly in the present invention.

[0049] Reference numerals in the drawings: 1 is a mechanical speed reduction mechanism, 2 is a motor, 3 is a coupling, 4 is a cooling device, 5 is an electro-hydraulic drive system, 6 is an outlet box, 7 is a load system, 8 is a stator assembly, 8a is a stator core, 8b is a stator winding, 9 is a rotor assembly, 9a is a rotor core, 9b is a rotor winding, 9c is a permanent magnet, 9d is an end ring, 10 is a main shaft, 10a is a main shaft connection part, 11 is a rotating drum, 12 is a rotating drum connection part, 13 is an oil passage hole, 14 is a connecting key, 15 is a convex part, 16 is a first stop block, 17 is a second stop block, 21 is a first bearing, 22 is a second bearing, 23 is a third bearing, 24 is a fourth bearing, 25 is a fifth bearing, 31 is a motor housing, 31a is a high-pressure oil passage in the motor housing, 31b is an oil outlet passage in the motor housing, 31c is a low-pressure oil passage in the motor housing, 32 is a front end cover, 32a is a low-pressure oil inlet passage in the front end cover, 32c is a high-pressure oil passage in the front end cover, 32d is a low-pressure oil passage in the front end cover, 32e is a high-pressure oil outlet passage in the front end cover, 32f is a communication hole in the front end cover, 33 is a rear end cover, 33a is a low-pressure oil inlet passage in the rear end cover, 33c is a high-pressure oil passage in the rear end cover, 33d is a low-pressure oil passage in the rear end cover, 33f is a communication hole in the rear end cover, 34 is a housing cavity, 40 is a swash plate, 41a is a swash plate support stop part, 42 is a flow distribution oil groove, 43 is a low-pressure flow distribution window, 44 is a high-pressure flow distribution window, 45 is a cylindrical sliding arc surface, 46 is a groove-shaped low-pressure port, 47 is a groove-shaped high-pressure port, 50 is a sliding plate, 50C is the axis center of the sliding plate, 51 is a static pressure support surface of the sliding plate, 52 is a convex table surface of the sliding plate, 53 is a kidney-shaped hole in the sliding plate, 54 is an outer sealing part of the sliding plate, 55 is an inner sealing part of the sliding plate, 56 is an interval sealing part of the sliding plate, 58 is a plunger ball socket, 60 is a pressing plate, 70 is a plunger, 71 is a plunger ball head, 72 is a central hole of the plunger, 73 is a tapered rod part, 74 is a plunger part, 80 is a cylinder block, 81 is a plunger hole, 100 is a central spring, 101 is a retaining ring, 102 is a ball hinge, 110 is a variable mechanism, 111 is a variable piston, 112 is a control valve, 113 is a variable spring, 120 is a hydraulic motor assembly, 121 is an output shaft, 122 is a motor cylinder block, 123 is a motor plunger, 124 is a cross beam, 125 is a roller, 126 is a flow distribution shaft, 126a is a low-pressure port of the flow distribution shaft, 126b is a high-pressure port of the flow distribution shaft, 127 is a motor housing, 130 is a valve group, 131 is a connecting oil pipe, 132 is an accumulator, 140 is a fuel tank housing, 141 is a fuel tank housing cavity, 142 is a bracket, 150 is a check valve, 160 is a make-up oil pump. Detailed implementation manners

[0050] The present invention will be described in detail below with reference to the accompanying drawings.

[0051] Although the present invention admits of embodiments in many different forms, the present specification and the drawings disclose only some specific forms as examples of the present invention. However, the present invention is not intended to be limited to the described embodiments. The scope of the present invention is given in the appended claims.

[0052] For ease of description, the embodiments of the present invention are shown in a typical orientation, in which the central axis of the main shaft of the electro-hydraulic drive system 5 is horizontally stationary. With the side of the hydraulic motor assembly being on the left and the rear end cover being on the right, terms such as "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "horizontal", "bottom", "inner", "outer", etc. used in the description are all referenced to this position. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, as well as a specific orientation structure and operation. It should be understood that the present invention can be manufactured, stored, transported, used, and sold in an orientation different from the described position.

[0053] Embodiment 1:

[0054] As Figures 2 to 5 shown, it is a preferred embodiment of the high-power electro-hydraulic drive system 5 of the present invention. In the shown preferred embodiment, the high-power electro-hydraulic drive system 5 is of a shaft-supported structure and an open-loop system, including a hydraulic motor assembly, an oil tank, and an electro-hydraulic integrated machine assembly accommodated in the cavity 141 of the oil tank housing. The electro-hydraulic integrated machine assembly includes a motor housing assembly, and a rotor assembly 9, a stator assembly 8, and a hydraulic pump assembly accommodated in the housing cavity 34 of the motor housing assembly. The hydraulic motor assembly is connected to the oil tank housing 140. The hydraulic pump assembly includes a flow distribution sliding disk pair and a plunger pair. The hydraulic pump assembly outputs high-pressure oil to the hydraulic motor assembly under the drive of electromagnetic force, driving the hydraulic motor assembly to work, and realizing the conversion from electrical energy to hydraulic energy and then to mechanical energy.

[0055] Specifically, the flow distribution sliding disk pair includes a swash plate 40 and a sliding disk 50 supported on the swash plate 40. The sliding disk 50 is an integral structure, and a static pressure oil film support is formed between the sliding disk 50 and the swash plate 40. The plunger pair includes the plunger hole wall of the cylinder block 80 and the plunger 70. Preferably, the plunger 70 is a conical structure with a large central hole provided at the center. The electro-hydraulic integrated machine assembly further includes a main shaft 10, a first bearing 21, and a second bearing 22. The central axis of the main shaft 10 coincides with the central axis of the cylinder block 80. One end of the main shaft 10 penetrates through the corresponding flow distribution sliding disk pair to the front end cover 32 in the motor housing assembly and is supported on the first bearing 21, and the other end penetrates through the corresponding flow distribution sliding disk pair to the rear end cover 33 in the motor housing assembly and is supported on the second bearing 22. The cylinder block 80 is supported on the main shaft 10 and is synchronously rotated with the main shaft 10 through key connection. The plunger pair includes the plunger hole wall of the cylinder block 80 and the plunger 70. The plunger 70 reciprocates in the plunger cavity of the cylinder block 80 to achieve oil suction and discharge work. Further, the electro-hydraulic integrated machine assembly further includes a rotating cylinder 11. The rotating cylinder 11 is respectively connected to the rotor assembly 9 and the cylinder block 80, so that the rotating cylinder 11, the cylinder block 80, and the rotor assembly 9 rotate synchronously. The cylinder block 80 is accommodated in the rotating cylinder, and the axial hydraulic pressures acting on the cylinder block are balanced or offset from each other.

[0056] Further, in this embodiment, preferably, the cylinder block 80 is an integral structure. The two ends of the cylinder block have a plurality of plunger holes 81 that are circumferentially and uniformly distributed around the central axis of the cylinder block. The plunger holes 81 of the cylinder block 80 are through-hole structures with openings at both ends. The rotating cylinder 11 is respectively connected to the cylinder block 80 and the rotor assembly 9, so that the rotating cylinder 11, the cylinder block 80, and the rotor assembly 9 rotate synchronously. Among them, the cylinder block 80 and the main shaft 10 can be set as an integral structure or a split structure. The integral structure means that the cylinder block and the main shaft are integrally machined from a single blank part. The split structure means that the cylinder block and the main shaft are machined separately and are connected by splines or other means.

[0057] Specifically, the motor includes, but is not limited to, an induction asynchronous motor, a permanent magnet DC motor, a permanent magnet synchronous motor, etc. Preferably, the motor is an induction asynchronous motor, including existing squirrel-cage asynchronous motors and wound-rotor asynchronous motors. The stator assembly 8 includes components such as a stator core 8a and a stator winding 8b. Among them, the stator core 8a is a part of the magnetic circuit and circuit of the motor, which is punched and laminated by thin silicon steel sheets coated with insulating paint on the surface. Its outer peripheral surface is fixedly connected to the motor housing 31 of the housing assembly. A plurality of notches (not shown) are provided on the inner peripheral surface of the stator core 8a. The stator winding 8b is embedded in the notches of the stator core 8a. The stator winding 8b is wound by insulated copper wires or insulated aluminum wires. The lead-out ends of the stator winding 8b are led to the lead-out box 6 provided on the motor housing 31. The rotor assembly 9 includes components such as a rotor core 9a and a rotor winding 9b. Among them, the rotor core 9a is also punched and laminated by thin silicon steel sheets coated with insulating paint on the surface. Its inner peripheral surface is fixedly connected to the rotating cylinder 11. The two side surfaces of the rotor core 9a are abutted against the protruding parts 15 of the rotating cylinder 11 through the first stoppers 16 to limit the axial displacement of the rotor core 9a and the rotating cylinder 11. A plurality of notches (not shown) are provided on the outer peripheral surface of the rotor core 9a. The rotor winding 9b is embedded in the notches of the rotor core 9a. The rotor winding 9b includes, but is not limited to, a squirrel-cage structure and a wound-rotor structure rotor winding. Among them, the squirrel-cage structure is to insert copper bars or aluminum bars as conducting bars into the slots on the rotor core 9a and connect them with copper rings or aluminum rings at both ends to form a cage-like structure. The wound-rotor structure is to arrange a coil winding on the rotor core 9a.

[0058] Among them, a certain air gap is maintained between the stator assembly 8 and the rotor assembly 9 of the motor to ensure reasonable power factor and starting performance during the operation of the motor. Alternatively, this air gap can also be filled with low-pressure cold oil in the housing cavity 34 of the housing assembly to dissipate the heat of the stator assembly 8 and the rotor assembly 9 of the motor.

[0059] Specifically, the hydraulic motor assembly 120 is used to convert hydraulic energy into mechanical energy, and includes, but is not limited to, radial piston motors and axial piston motor types. Preferably, the hydraulic motor assembly 120 is a radial piston motor, including a crankshaft-type radial piston motor and an internal curve-type radial piston motor. Further preferably, the hydraulic motor assembly 120 is a crossbeam-force transmission internal curve piston motor, such as Figure 3As shown, the hydraulic motor assembly 120 includes a motor housing 127, an output shaft 121 connected to a load, a motor cylinder block 122 connected to the output shaft 121, a motor plunger 123 with a radial displacement, a crossbeam 124 in contact with the motor plunger 123, a roller 125, and a distribution shaft 126. The motor plunger 123 transmits force to the crossbeam 124. The crossbeam 124 is supported on the roller 125 and can slide in the radial groove of the motor cylinder block 122. The top of the motor plunger 123 has a configuration of a spherical surface or a conical surface and is in contact with the crossbeam 124 to transmit hydraulic pressure. The motor plunger 123 can be arranged in a multi-row structure to increase the displacement, preferably 2 - 3 rows. The distribution shaft 126 includes a distribution shaft low-pressure port 126a and a distribution shaft high-pressure port 126b.

[0060] Predictably, the load system 7 connected to the hydraulic motor assembly includes, but is not limited to, an internal mixer, a kneader, an extruder in industrial production machinery, a crusher, a coal mill, a scraper conveyor, a bucket wheel machine, and various belt conveying equipment in mining machinery, a drilling rig for oilfield exploitation, a ship propulsion system, helicopter blades, a port crane hoisting equipment, etc.

[0061] Specifically, the motor housing assembly includes a front end cover 32, a rear end cover 33, and a motor housing 31. The front end cover 32 is used to close one end opening of the motor housing 31, and the rear end cover 33 is used to close the other end opening of the motor housing 31. The motor housing 31, the front end cover 32, and the rear end cover 33 enclose a housing cavity 34 for accommodating a rotor assembly, a stator assembly, and a hydraulic pump assembly. The swash plate 40 on the side of the hydraulic pump assembly close to the hydraulic motor assembly abuts against one side end face of the front end cover 32, and the distribution shaft 126 of the hydraulic motor assembly abuts against the other side end face of the front end cover 32. The motor housing 31 is supported on the oil tank housing 140 by a bracket 142.

[0062] Further, the high-power electro-hydraulic drive system is an open-loop system. The front end cover 32 is provided with a front end cover low-pressure oil inlet passage 32a and a front end cover high-pressure oil passage 32c. The rear end cover 33 is provided with a rear end cover low-pressure oil inlet passage 33a, a rear end cover high-pressure oil passage 33c, and a rear end cover low-pressure oil passage 33d. The front end cover high-pressure oil passage 32c is communicated with the distribution shaft high-pressure port 126b. The front end cover low-pressure oil inlet passage 32a, the rear end cover low-pressure oil inlet passage 33a, and the distribution shaft low-pressure port 126a respectively open to the oil tank housing cavity 141. When sucking oil, the low-pressure cold oil in the oil tank housing cavity 141 enters the cylinder block plunger hole 81 of the hydraulic pump assembly through the front end cover low-pressure oil inlet passage 32a and the rear end cover low-pressure oil inlet passage 33a to take away heat and achieve self-cooling.

[0063] Further, the high-pressure hydraulic fluid after the action of the hydraulic pump assembly flows into the high-pressure port 126a of the distribution shaft in two paths. One path enters the front-end cover high-pressure oil passage 32c through the front-end cover high-pressure oil outlet passage 32e, and the other path enters the rear-end cover oil inlet passage 33c through the distribution sliding disk pair in contact with the rear-end cover 33, and then reaches the front-end cover high-pressure oil passage 32c through the motor housing high-pressure oil passage 31a or the connecting oil pipe 133. The two paths of high-pressure hydraulic fluid finally enter the motor cylinder block 122 of the hydraulic motor assembly through the high-pressure port 126b of the distribution shaft. The high-pressure hydraulic fluid drives the hydraulic motor assembly to move and drive the load to work.

[0064] Specifically, the distribution sliding disk pair includes a sliding disk 50 and an inclined disk 40 supported on the rear-end cover 33. The sliding disk static pressure supporting surface 51 of the sliding disk 50 is supported on the inclined disk 40 and keeps close fit with the supporting surface of the inclined disk 40. One end of the sliding disk 50 is provided with a plurality of sliding disk waist-shaped holes 53, and the other end surface of the sliding disk 50 is provided with a plurality of plunger ball sockets 58. The sliding disk waist-shaped holes 53 on the sliding disk 50 penetrate through to the plunger ball sockets 58. The inclined disk 40 is provided with a low-pressure distribution window 43, a high-pressure distribution window 44, and a distribution oil groove 42.

[0065] Further, the inclined disk 40 in contact with the front-end cover 32 is a fixed-angle inclined disk, that is, the angle of this inclined disk 40 cannot be rotated. The high-pressure distribution window 44 of this inclined disk is communicated with the front-end cover high-pressure oil passage 32c on the front-end cover 32, and the low-pressure distribution window 43 of this inclined disk is communicated with the front-end cover low-pressure oil inlet passage 32a on the front-end cover 32; the inclined disk 40 in contact with the rear-end cover 33 is a variable-angle inclined disk. The high-pressure distribution window 44 of this inclined disk is communicated with the rear-end cover high-pressure oil passage 33c on the rear-end cover 33, and the low-pressure distribution window 43 of this inclined disk is communicated with the rear-end cover low-pressure oil inlet passage 33a on the rear-end cover 33.

[0066] Further, the supporting surface of the inclined disk 40 opposite to the rear-end cover 33 has a cylindrical sliding arc surface 45 formed in a cylindrical shape. On the cylindrical sliding arc surface 45 of the inclined disk 40, there are a groove-shaped low-pressure port 46 and a groove-shaped high-pressure port 47 configured in a groove shape. The groove-shaped low-pressure port 46 is communicated with the rear-end cover low-pressure oil inlet passage 33a, and the groove-shaped high-pressure port 47 is communicated with the rear-end cover high-pressure oil passage 33c.

[0067] Analyzing from the structure, it can be known that this open-type electro-hydraulic drive system has a self-cooling function, such as Figure 5As shown in the figure, it is the internal fluid flow diagram of the open electro-hydraulic drive system 5, and its internal oil flow path is as follows: First, the low-pressure cold oil is stored in the cavity 141 of the fuel tank housing. During operation, electrical energy is input, and the rotor assembly 9 of the motor drives the cylinder block of the hydraulic pump assembly to rotate. The low-pressure cold oil enters the cylinder block plunger holes 81 of the hydraulic pump assembly from the cavity 141 of the fuel tank housing through the low-pressure oil inlet passage 32a of the front end cover and the low-pressure oil inlet passage 33a of the rear end cover. After the action of the hydraulic pump assembly, the high-pressure oil enters the high-pressure port 126b of the distribution shaft through the high-pressure oil passage of the motor housing assembly. After the high-pressure oil drives the hydraulic motor assembly to move, low-pressure oil is generated, and the low-pressure oil is output to the cavity 141 of the fuel tank housing through the low-pressure port 126a of the distribution shaft. Since most or all of the electro-hydraulic integrated machine assembly is immersed in the low-pressure cold oil in the fuel tank, the heat generated by the electro-hydraulic integrated machine assembly is dissipated in the fuel tank to achieve self-cooling. Particularly significantly, the temperature of the stator assembly of the electro-hydraulic integrated machine assembly is greatly reduced.

[0068] To further reduce the temperature inside the electro-hydraulic integrated machine assembly, as Figure 3 shown, a front end cover communication hole 32f is provided on the front end cover 32, and a rear end cover communication hole 33f is provided on the rear end cover 33. Both the front end cover communication hole 32f and the rear end cover communication hole 33f connect the housing cavity 34 of the motor with the cavity 141 of the fuel tank housing, so that the cold oil in the cavity 141 of the fuel tank housing can enter the housing cavity 34, and the hot oil in the housing cavity 34 can be discharged into the cavity 141 of the fuel tank housing. This structure enables each friction pair and the rotor assembly and stator assembly components placed in the housing cavity 34 to be immersed in the low-temperature oil, and discharges the heat generated by the three major friction pairs of the stator assembly, rotor assembly, and hydraulic motor assembly into the cavity 141 of the fuel tank housing.

[0069] At the same time, this structure also has the characteristics of small volume, light weight, high power density, high efficiency, and low noise. As Figure 1 shown, it is a traditional low-speed high-torque drive system, in which the mechanical reduction mechanism 1, the motor 2, and the coupling 3 are arranged axially as independent components, with a long axial length, large occupied space, and heavy weight. Figure 2 For the electro-hydraulic drive system in the present invention, it cancels the mechanical reduction mechanism 1 in the traditional drive system, gives full play to the high power-to-weight ratio characteristics of hydraulic transmission, and greatly reduces the overall volume and total weight of the drive system, which is irreplaceable by other drive systems; the motor, hydraulic motor assembly, hydraulic pump assembly, and fuel tank are highly integrated into one body, eliminating connecting components such as couplings and cooling devices, reducing energy conversion, power transmission links, and additional energy losses of the cooling device; the motor and hydraulic pump are coaxial and co-shell, canceling the coupling and cooling device, and significantly reducing the noise.

[0070] Specifically, as Figure 11 and 12As shown, the outer peripheral surface of the rotary drum 11 is connected to the rotor assembly 9. An inwardly extending drum connection part 12 is provided inside the rotary drum 11. A plurality of oil passing holes 13 are circumferentially arranged in the drum connection part 12. The oil passing holes 13 communicate with the housing cavities 34 on both sides, enabling the low-pressure oil to pass through smoothly. A connection key 14 that circumferentially mates with the outer periphery of the cylinder block 80 is arranged inside the drum connection part 12 in the circumferential direction. Alternatively, the connection between the drum connection part and the cylinder block may also include, but is not limited to, interference fit connection, bolt connection, etc.

[0071] Furthermore, a restraint device for restricting axial movement is provided on the rotary drum 11. The restraint device includes protruding portions 15 that protrude outward on both sides of the rotary drum 11 for restricting the axial displacement of the motor rotor, and a first stopper 16 clamped between the motor rotor and the protruding portions 15. The restraint device further includes a second stopper 17 arranged on the outer circumference of the cylinder block 80 for restricting the axial displacement of the rotary drum 11. The second stopper 17 is connected to the connection part 12 of the rotary drum 11.

[0072] Furthermore, a variable mechanism 110 is provided on one side of the rear end cover 33. The variable mechanism is used to adjust the displacement of the hydraulic pump assembly to achieve stepless speed control. The variable mechanism is a swash plate angle control type variable structure. The swash plate angle control type variable mechanism includes a variable piston 111, a control valve 112, and a variable spring 113. The control valve 112 is connected to the rear end cover 33. A plurality of fluid flow channels are arranged inside the control valve 112. The control valve 112 controls the movement of the variable piston 111 by controlling the oil flowing into the variable piston 111 to achieve a change in the angle of the swash plate 40. The control valve 112 can be set with multiple variable control methods according to the working condition parameters. The variable spring 113 functions to reset.

[0073] More specifically, a plurality of plunger ball sockets 58 are arranged at the circumferential relative positions of the end face of the swash plate 50 facing the cylinder block 80. As shown in FIGS. Figure 6 、 7 and 8, the plunger ball sockets 58 form concave portions with openings approximately in a hemispherical shape on the end face of the swash plate 50. The plunger ball sockets 58 support the plunger ball heads 71 in a state of being evenly spaced on a common circumference centered on the swash plate axis 50C. After the plungers 70 are installed in the plunger ball sockets 58, they are fixed to the end face of the swash plate 50 by a pressure plate 60, restricting the movement of the plungers 70 away from the end face of the swash plate 50. Specifically, the method for fixing the plungers 70 to the end face of the swash plate 50 is not limited to using a pressure plate. For example, a form-locking clamping device (not shown) may be provided on the swash plate 50, and the clamping device can fix the plunger ball heads 71 by wrapping more than 180 degrees.

[0074] Among them, a swashplate static pressure bearing surface 51 is provided on the end surface of the swashplate 50 facing the inclined disk 40. As Figure 7 shown, the swashplate axis 50C forms a certain angle with the main shaft axis. The swashplate static pressure bearing surface 51 is supported on the inclined disk 40 and always maintains a sliding fit with the inclined disk 40. A plurality of swashplate waist-shaped holes 53 configured as waist shapes are provided on the swashplate static pressure bearing surface 51. Preferably, the swashplate waist-shaped holes 53 are uniformly distributed on the swashplate static pressure bearing surface 51 centered on the swashplate axis 50C. The swashplate waist-shaped holes 53 communicate with the plunger ball socket 58.

[0075] Furthermore, a swashplate convex table surface 52 extending from the swashplate axis 50C toward the inclined disk 40 is provided on the end surface of the swashplate 50 facing the inclined disk 40. The swashplate convex table surface 52 is composed of a region surrounded by an inner diameter R1 and an outer diameter R2. The swashplate convex table surface 52 and the inclined disk 40 bearing surface are in sliding contact with each other. A plurality of swashplate waist-shaped holes 53 are provided at positions corresponding to the plunger ball socket 58 on the swashplate convex table surface 52. Preferably, the swashplate waist-shaped holes 53 are uniformly spaced on the swashplate convex table surface 52 in a common circumference centered on the swashplate axis 50C.

[0076] Among them, an effective static pressure oil film support is formed between the swashplate convex table surface 52 and the inclined disk 40 bearing surface. A sealing portion for sealing the action of the oil fluid is provided on the swashplate convex table surface 52. The sealing portion is provided around the swashplate waist-shaped holes 53 on the inner and outer circumferences of the swashplate waist-shaped holes 53. The sealing portion includes a swashplate inner sealing portion 55, a swashplate outer sealing portion 54 distributed radially inside and outside the swashplate waist-shaped holes 53, and a swashplate interval sealing portion 56 distributed between adjacent swashplate waist-shaped holes 53. The swashplate inner sealing portion 55 is a region surrounded by the inner edge of the swashplate waist-shaped hole 53 and the inner diameter R1 of the swashplate convex table surface 52. The swashplate outer sealing portion 54 is a region surrounded by the outer edge of the swashplate waist-shaped hole 53 and the outer diameter R2 of the swashplate convex table surface 52. The swashplate interval sealing portion 56 is an interval convex table surface region between adjacent swashplate waist-shaped holes 53. A certain reasonable gap is always maintained between the sealing portion of the swashplate convex table surface 52 and the inclined disk 40 bearing surface so that the oil film leakage is at a reasonable level.

[0077] Specifically, the plunger 70 includes a plunger ball head 71 with one end supported on the plunger socket 58 of the swash plate 50 and fixed to the end face of the swash plate 50 via a pressure plate 60, a plunger central hole 72 for communicating the plunger hole 81 and the plunger socket 58, a tapered rod portion 73 with a conical outer peripheral surface, and a plunger portion 74 that is in clearance fit with the wall of the cylinder block plunger hole and can reciprocate therein. The plunger ball head 71 is spherical and can slide freely on the plunger socket 58 of the swash plate 50. The plunger central hole 72 is a through-hole structure with a large aperture and serves as an oil suction and / or discharge passage. At least one sealing ring is usually provided on the plunger portion 74 to seal the liquid. The tapered rod portion 73 is generally conical and gradually increases from the plunger ball end to the plunger portion 74. When the plunger 70 moves to a certain position, the tapered rod portion 74 contacts the inner circumferential surface of the plunger hole 81 to play a force transmission role. It should be noted that the plunger 70 is not limited to the tapered plunger type and may also include a connecting rod-plunger with ball heads at both ends or a spherical plunger with a universal hinge.

[0078] During operation, the hydraulic pressure acts on the plunger 70 and is further transmitted to the swash plate 50. Generally, the axial force exerted by the plunger 70 on the swash plate 50 is greater than the sum of the support force exerted by the swash plate 40 on the swash plate 50 through the oil film and the return force of the plunger 70. Therefore, the swash plate 50 always abuts against the swash plate 40 through an oil film and slides thereon.

[0079] Considering that initial sealing is still required between the swash plate and the inclined plate at startup to quickly establish the oil pressure, an initial sealing device must be provided on one side of the flow distribution swash plate pair.

[0080] Preferably, one type of initial sealing device, as Figure 13 shown, a spring preloading device is provided between the swash plate 50 and the cylinder block 80. This spring preloading device gives the flow distribution swash plate pair a certain initial contact force. The spring preloading device includes a central spring 100, a retaining ring 101, and a ball joint 102. One end of the preloading spring force of the central spring 100 acts on the pressure plate 60 through the ball joint 102 and is further transmitted to the swash plate 50, and the other end acts on the end of the cylinder block through the retaining ring 101 with the preloading force.

[0081] Preferably, another type of initial sealing device, as Figure 3 and 4 shown, a restraining device can also be provided on the swash plate 50 and / or the cylinder block 80. The restraining device has the function of restricting the swash plate 50 of the flow distribution swash plate pair from moving away from the swash plate 40.

[0082] Further, the constraint device includes a swash plate stop portion that protrudes outward on one side of the sliding plate 50 close to the sliding plate hydrostatic bearing surface 51, and an engaging device provided on the swash plate support stop portion 41a. The stop portion is used to limit the movement of the third bearing 23. The engaging device includes an engaging circumferential groove provided on the swash plate support stop portion 41a adjacent to the third bearing 23, and a snap ring (not shown) provided on the engaging inner circumferential groove. The snap ring restricts the sliding plate from moving away from the end face of the swash plate 40 in a manner that restricts the outward movement of the third bearing 23.

[0083] Predictably, an elastic gasket (not shown) can also be appropriately provided between the stop portion and the third bearing 23 or between the snap ring and the third bearing 23, so that in addition to restricting the sliding plate from moving away from the end face of the swash plate, the constraint assembly also has a certain initial pre-tightening force to maintain the pre-tightened state of the sliding plate and the swash plate. Similarly, the constraint method of the engaging device can also be realized by the interference fit between the third bearing 23 and the swash plate support stop portion 41a. An engaging circumferential groove and a snap ring that cooperate with the engaging circumferential groove are provided on the swash plate support stop portion 41a adjacent to the third bearing 23 to play a further constraining role.

[0084] Embodiment 2:

[0085] As Figure 13 shown, the difference from Embodiment 1 lies in the number and structure of the cylinder blocks in the hydraulic pump assembly.

[0086] Specifically, the hydraulic pump assembly includes two cylinder blocks 80. The cylinder blocks 80 have a columnar configuration with a circular cross-section in the radial direction and are accommodated in the cavity of the rotating cylinder 11. The cylinder blocks 80 have a plurality of plunger holes 81 that are uniformly distributed circumferentially around the central axis of the cylinder block and a main shaft assembly hole at the center for accommodating the main shaft. The plunger holes 81 of the cylinder blocks 80 have a structure with one end closed and one end open. Preferably, the number of the plunger holes 81 is generally set to 7 or 9.

[0087] Further, the main shaft 10 passes through the main shaft assembly hole of the cylinder block 80 and is connected to the cylinder block 80 by means of a connection key provided on the outer peripheral surface of its shaft body. The cylinder block 80 is supported on the main shaft 10 in a manner that moves synchronously with the main shaft 10. An outwardly protruding main shaft connection portion 10a is circumferentially provided in the middle of the main shaft 10, and an inwardly protruding rotating cylinder connection portion 12 is circumferentially provided in the middle of the rotating cylinder 11. The rotating cylinder 11 is respectively connected to the main shaft 10 and the rotor assembly 9, so that the rotating cylinder 11, the main shaft 10, the cylinder block 80, and the rotor assembly 9 rotate synchronously. The axially opposite and closed ends of the cylinder blocks abut against both ends of the main shaft connection portion 10a, so that the axial hydraulic pressures acting on the two ends of the cylinder blocks are balanced with each other.

[0088] It should be noted that there is no flow distribution plate abutting against the end of the cylinder block 80, so one friction pair is reduced, and its volumetric efficiency is improved; since there is no abutting flow distribution plate, the end of the cylinder block 80 does not need precision machining, reducing the manufacturing and usage costs; without a flow distribution plate at the end of the cylinder block 80, even if there is partial lateral force, problems such as uneven wear and failure will not occur.

[0089] Embodiment 3:

[0090] As Figure 14 shown, the difference from Embodiment 1 is that this embodiment is a closed system. Therefore, its oil passage structure and liquid flow path are also different, and other structures can refer to those described in Embodiment 1.

[0091] Specifically, the electro-hydraulic drive system is a closed-loop system. A front-end cover high-pressure oil passage 32c and a front-end cover low-pressure oil passage 32d are provided on the front-end cover 32. A rear-end cover low-pressure inlet oil passage 33a, a rear-end cover high-pressure oil passage 33c, and a rear-end cover low-pressure oil passage 33d are provided on the rear-end cover 33. The front-end cover high-pressure oil passage 32c is communicated with the high-pressure port 126b of the flow distribution shaft. The front-end cover low-pressure oil passage 32d is respectively communicated with the low-pressure port 126a of the flow distribution shaft and the motor housing low-pressure oil passage 31c.

[0092] At the initial operation, the low-pressure oil liquid in the oil tank housing cavity 141 enters the hydraulic pump assembly from the rear-end cover low-pressure inlet oil passage 33a. After being acted on to form high-pressure oil liquid, it is transported to the hydraulic motor assembly through the rear-end cover high-pressure oil passage 33c and the front-end cover high-pressure oil passage 32c. The low-pressure oil liquid formed after being acted on by the hydraulic motor assembly flows out from the low-pressure port 126a of the flow distribution shaft and returns to the hydraulic pump assembly through the front-end cover low-pressure oil passage 32d and the rear-end cover low-pressure oil passage 33d, forming a closed loop.

[0093] Furthermore, a check valve 150 is provided on the rear-end cover. The oil outlet (not shown) of the check valve 150 is communicated with the rear-end cover low-pressure inlet oil passage 33a. The oil inlet of the check valve 150 opens towards the oil tank housing cavity 141. The check valve 150 only allows oil liquid to enter from the oil tank housing cavity 141 into the rear-end cover low-pressure inlet oil passage 33a. The check valve 150 is used to supplement the oil leakage in the closed loop.

[0094] Furthermore, a makeup oil pump 160 is provided on the rear-end cover. The makeup oil pump 160 is connected to one end of the main shaft 10. The makeup oil pump 160 is communicated with the rear-end cover low-pressure inlet oil passage 33a. The makeup oil pump 160 is used to supplement the oil leakage in the closed loop. The makeup oil pump 160 is bolted to the rear-end cover 33. The externally connected makeup oil pump 160 can be a gear pump or a vane pump, etc.

[0095] Specifically, a one-way valve 150 and a makeup oil pump 160 are provided on the rear end cover 33. The oil inlet of the one-way valve 150 is connected to the oil outlet of the makeup oil pump 160, and the oil outlet of the one-way valve 150 is communicated with the low-pressure oil inlet passage 33a of the rear end cover. The two jointly supplement the oil leakage in the closed circuit.

[0096] This closed circuit is beneficial to reducing the volume of the fuel tank and improving the operating efficiency of the system.

[0097] Example 4:

[0098] As Figures 13 to 16 shown, the difference from other embodiments is that a valve group 130 for pressure, flow rate, and direction adjustment is provided.

[0099] Specifically, a motor housing oil outlet passage 31b is provided on the motor housing 31. The motor housing oil outlet passage 31b is communicated with the motor housing high-pressure oil passage 31a. One end of a connecting oil pipe 131 is communicated with the motor housing oil outlet passage 31b, and the other end is connected to the valve group 130. The valve group 130 is used for the control of pressure, flow rate, and direction. The valve group 130 includes one or a combination of a pressure valve, a flow valve, and a direction valve.

[0100] Example 5:

[0101] As Figures 13 to 16 shown, the difference from other embodiments is that an accumulator 132 is provided on the electro-hydraulic drive system 5.

[0102] Specifically, an accumulator 132 is provided on the fuel tank housing 140. The accumulator 132 is connected to the valve group 130. The accumulator has functions such as assisting in starting, stabilizing pressure, supplementing leaked oil, and providing an auxiliary control oil source. It can be predicted that the accumulator 132 may not be connected to the fuel tank housing 140 but be placed independently, and the accumulator is connected to the valve group through a hydraulic oil pipe.

[0103] Example 6:

[0104] As Figure 15 shown, the main difference from other embodiments is that this embodiment is a rotary drum supported electro-hydraulic drive system.

[0105] Specifically, the electro-hydraulic drive system 5 includes a fourth bearing 24 and a fifth bearing 25. The fourth bearing 24 and the fifth bearing 25 are respectively clamped between the rotary drum 11 and the housing assembly. The rotor assembly 9 and the hydraulic pump assembly are supported on the fourth bearing 24 and the fifth bearing 25 through the rotary drum 11 and rotate synchronously. The plunger 70 reciprocates in the plunger cavity of the cylinder block 80 to achieve oil suction and discharge work.

[0106] Example 7:

[0107] As Figure 16 shown, it is different from other embodiments in that the rotor assembly structure is different.

[0108] Specifically, the rotor assembly 9 includes a rotor core 9a connected to the outer peripheral surface of the drum 11 and a permanent magnet 9c nested in the rotor core 9a. End rings 9d are provided at both ends of the permanent magnet 9c to restrict the axial movement of the permanent magnet.

[0109] The above content is a further detailed description of the present invention in combination with specific preferred technical solutions. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can be made. All technical solutions and their improvements that do not depart from the spirit and scope of the present invention should be covered by the scope of the claims of the present invention.

Claims

1. A high-power, low-speed and high-torque electro-hydraulic drive system, characterized in that: It includes a hydraulic motor assembly, an oil tank, and an electro-hydraulic integrated machine assembly housed in the cavity (141) of the oil tank housing. The electro-hydraulic integrated machine assembly includes a motor housing assembly, and a rotor assembly (9), a stator assembly (8), and a hydraulic pump assembly housed in the housing cavity (34) of the motor housing assembly. The hydraulic motor assembly is connected to the oil tank housing (140). The hydraulic pump assembly outputs high-pressure hydraulic oil to the hydraulic motor assembly under the drive of electromagnetic force, driving the hydraulic motor assembly to work, realizing the conversion from electrical energy to hydraulic energy and then to mechanical energy; The hydraulic pump assembly includes a valve plate-slide pair and a plunger pair. The valve plate-slide pair includes a swash plate (40) and a slide plate (50) supported on the swash plate (40). The slide plate (50) is of an integral disc structure. A static pressure oil film support is formed between the slide plate (50) and the swash plate (40). The plunger pair includes a cylinder block (80) and a plunger (70); The electro-hydraulic integrated machine assembly further includes a main shaft (10) and a rotating cylinder (11). The main shaft (10) is connected to the cylinder block (80). The rotating cylinder (11) is respectively connected to the rotor assembly (9) and the cylinder block (80), so that the rotating cylinder (11), the cylinder block (80), and the rotor assembly (9) rotate synchronously. The cylinder block (80) is housed in the rotating cylinder (11) and the axial hydraulic pressures acting on the cylinder block (80) are balanced or offset from each other; The motor housing assembly includes a front end cover (32), a rear end cover (33), and a motor housing (31). The swash plate (40) of the valve plate-slide pair on the side of the hydraulic pump assembly close to the hydraulic motor assembly abuts against one end face of the front end cover (32). The valve plate shaft (126) of the hydraulic motor assembly abuts against the other end face of the front end cover (32). The valve plate shaft (126) is provided with a valve plate shaft low-pressure port (126a) and a valve plate shaft high-pressure port (126b); The electro-hydraulic drive system (5) is an open-loop system. The front end cover (32) is provided with a front end cover low-pressure oil inlet passage (32a) and a front end cover high-pressure oil passage (32c). The rear end cover (33) is provided with a rear end cover low-pressure oil inlet passage (33a), a rear end cover high-pressure oil passage (33c), and a rear end cover low-pressure oil passage (33d). The front end cover high-pressure oil passage (32c) is communicated with the valve plate shaft high-pressure port (126b). The front end cover low-pressure oil inlet passage (32a), the rear end cover low-pressure oil inlet passage (33a), and the valve plate shaft low-pressure port (126a) respectively open to the cavity (141) of the oil tank housing, so that the oil in the cavity (141) of the oil tank housing enters the cylinder block plunger holes (81) of the hydraulic pump assembly to take away heat and realize self-cooling; Alternatively, the electro-hydraulic drive system (5) is a closed-loop system. A front-end cover high-pressure oil passage (32c) and a front-end cover low-pressure oil passage (32d) are provided on the front-end cover (32), and a rear-end cover low-pressure oil inlet passage (33a), a rear-end cover high-pressure oil passage (33c), and a rear-end cover low-pressure oil passage (33d) are provided on the rear-end cover (33). The front-end cover high-pressure oil passage (32c) communicates with the high-pressure port (126b) of the flow distribution shaft, and the front-end cover low-pressure oil passage (32d) communicates with the low-pressure port (126a) of the flow distribution shaft and the motor housing low-pressure oil passage (31c) respectively. After the low-pressure hydraulic fluid enters the hydraulic pump assembly from the rear-end cover low-pressure oil inlet passage (33a), the high-pressure hydraulic fluid formed by the action is transported to the hydraulic motor assembly through the front-end cover high-pressure oil passage (32c), and the low-pressure hydraulic fluid formed by the action returns to the hydraulic pump assembly through the front-end cover low-pressure oil passage (32d), forming a closed loop.

2. The high-power low-speed high-torque electro-hydraulic drive system according to claim 1, wherein: The cylinder block (80) is of an integral structure. Both ends of the cylinder block (80) have a plurality of plunger holes (81) evenly distributed circumferentially around the central axis of the cylinder block. The plunger holes (81) of the cylinder block (80) are through-hole structures with openings at both ends.

3. The high-power low-speed high-torque electro-hydraulic drive system according to claim 1, characterized in that: The cylinder block (80) consists of two opposed independent cylinder blocks. The cylinder block (80) has a plurality of plunger holes (81) evenly distributed circumferentially around the central axis of the cylinder block. The plunger holes (81) of the cylinder block (80) are blind-hole structures with one end closed and one end open, and the end faces of the cylinder blocks (80) on the opposed side are closed.

4. The high-power low-speed high-torque electro-hydraulic drive system according to claim 3, characterized in that: A main shaft connecting portion (10a) protruding outward is circumferentially provided in the middle of the main shaft (10), and a drum connecting portion (12) protruding inward is circumferentially provided in the middle of the drum (11). The drum (11) is connected to the main shaft (10) and the rotor assembly (9) respectively, so that the drum (11), the main shaft (10), the cylinder block (80), and the rotor assembly (9) rotate synchronously. The ends of the cylinder blocks on the opposed and closed side abut against both ends of the main shaft connecting portion (10a), so that the axial hydraulic pressures acting on the two ends of the cylinder blocks are balanced with each other.

5. The high-power low-speed high-torque electro-hydraulic drive system according to claim 1, characterized in that: When the electro-hydraulic drive system (5) is a closed-loop system, a check valve (150) and / or a makeup oil pump (160) are provided on the rear-end cover (33). The makeup oil pump (160) is connected to one end of the main shaft (10). The oil outlet of the check valve (150) communicates with the rear-end cover low-pressure oil inlet passage (33a). The check valve (150) and / or the makeup oil pump (160) are used to supplement the oil leakage in the closed loop.

6. The high-power low-speed high-torque electro-hydraulic drive system according to claim 1, wherein: A valve group (130) is connected to the fuel tank housing (140) or the motor housing (31). The motor housing (31) is provided with a motor housing high-pressure oil passage (31a). The oil inlet of the valve group (130) communicates with the motor housing high-pressure oil passage (31a). The valve group (130) is used for controlling the pressure, flow rate, and direction of the hydraulic pump assembly. The valve group (130) includes one or a combination of a pressure valve, a flow valve, and a direction valve.

7. The high-power low-speed high-torque electro-hydraulic drive system according to claim 6, characterized in that: An accumulator (132) is provided on the electro-hydraulic drive system (5). The accumulator (132) is connected to the valve group (130), and the accumulator (132) has one or more functions including auxiliary starting, stabilizing pressure, supplementing leaked oil, and providing an auxiliary control oil source.

8. The high-power low-speed high-torque electro-hydraulic drive system according to claim 1, wherein: The hydraulic pump assembly includes two port plate slide pairs. The swash plates (40) of the port plate slide pairs are respectively abutted against the front end cover (32) and the rear end cover (33). Among them, the swash plate (40) abutted against the front end cover (32) is a swash plate with a fixed inclination angle, and the swash plate (40) abutted against the rear end cover (33) is a variable-angle swash plate.

9. The high-power low-speed high-torque electro-hydraulic drive system according to claim 8, wherein: A variable mechanism is provided on the rear end cover (33). The supporting surface on the swash plate (40) opposed to the rear end cover (33) has a cylindrical sliding arc surface (45) formed as a cylinder. The variable mechanism includes a variable piston (111), a control valve (112), and a variable spring (113). The variable piston (111) drives the swash plate (40) to slide on the cylindrical sliding arc surface (45) to achieve stepless speed change control.

10. The high-power low-speed high-torque electro-hydraulic drive system according to any one of claims 1 to 9, characterized in that: The hydraulic pump assembly is of a shaft-supported structure. It further includes a first bearing (21) and a second bearing (22). The axis of the main shaft (10) coincides with the axis of the cylinder block (80). One end of the main shaft (10) penetrates through the port plate slide pair at the corresponding end to the front end cover (32) and is supported on the first bearing (21), and the other end penetrates through the port plate slide pair at the corresponding end to the rear end cover (33) and is supported on the second bearing (22). The cylinder block (80) is supported on the main shaft (10) and is connected to the main shaft (10) by a key to achieve synchronous rotation. The plunger pair includes the plunger hole wall of the cylinder block (80) and the plunger (70). The plunger (70) reciprocates in the plunger cavity of the cylinder block (80) to achieve oil suction and discharge.

11. The high-power low-speed high-torque electro-hydraulic drive system according to any one of claims 1 to 9, characterized in that: The hydraulic pump assembly is of a rotary drum-supported structure. It further includes a fourth bearing (24) and a fifth bearing (25). The fourth bearing (24) and the fifth bearing (25) are respectively clamped between the rotary drum (11) and the motor housing assembly. The rotor assembly (9) and the hydraulic pump assembly are supported on the fourth bearing (24) and the fifth bearing (25) by the rotary drum (11) and achieve synchronous rotation. The plunger pair includes the plunger hole wall of the cylinder block (80) and the plunger (70). The plunger (70) reciprocates in the plunger cavity of the cylinder block (80) to achieve oil suction and discharge.

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