Hydraulic displacement motor and fluid displacement motor

Abstract

Hydraulic displacement motors and fluid displacement motors are described herein. In one example, a hydraulic displacement motor includes a valve plate associated with at least one piston of a cylinder block, the valve plate including a plurality of grooves in fluid connection with a passage including a valve.

Description

Technical Field

[0001] The present disclosure generally relates to hydraulic motors, and more particularly, to bent-axis or axial motors. Background Art

[0002] Hydraulic axial piston motors can be bent-axis motors, including a bent-axis unit (BAU) rotating group or an axial unit. These units can include fixed or variable displacements. The balance of the motor can be predetermined at the manufacturing stage, which may affect the mechanical efficiency and volumetric efficiency of the motor. Therefore, a motor that can dynamically adjust the balance during operation may be needed to optimize its mechanical and volumetric efficiencies. Summary of the Utility Model

[0003] In one embodiment, at least a portion of the above problems can be solved by a hydraulic displacement motor including a valve plate connected to at least one piston of a cylinder block, the valve plate including a plurality of grooves fluidly connected to a passage including a valve. In this way, the balance of the valve can be adjusted during operation, thereby improving its efficiency.

[0004] It should be understood that the above summary is to introduce concepts further described in the detailed description in a simplified form. It is not intended to identify the key or essential features of the claimed subject matter, the scope of which is uniquely determined by the claims that follow the detailed description. Moreover, the claimed subject matter is not limited to embodiments that solve any disadvantages noted above or in any part of this disclosure. Brief Description of the Drawings

[0005] Aspects of the present disclosure can be better understood by reading the following detailed description and referring to the drawings:

[0006] Figure 1 is a schematic diagram of a motor system according to one or more embodiments of the present disclosure;

[0007] Figure 2 is a cross-sectional schematic diagram of a motor including an actuator in a first position according to one or more embodiments of the present disclosure;

[0008] Figure 3 shows a detailed view of a valve plate of a motor system according to one or more embodiments of the present disclosure;

[0009] Figure 4 shows a motor hydraulic circuit according to one or more embodiments of the present disclosure; and

[0010] Figures 5A and 5B show the difference in fluid distribution between a motor with the valve closed and a motor with the valve at least partially open according to one or more embodiments of the present disclosure. Detailed Description

[0011] A system for a fixed displacement motor is provided. The motors of the present disclosure can be variable balance axial or bent axial piston motors, including a valve plate with one or more cuts and / or grooves that, in combination with the operation of valves, facilitate the variable balance described herein. Fluid can apply forces that cause imbalance. Imbalance can also occur due to vibration and other conditions. Conventional motors have considered imbalance tolerances during manufacturing, which can cover various operating conditions that cause imbalance. However, there are situations that result in imbalances outside of the imbalance tolerances, especially after the motor has aged. The valve plate includes different regions that can provide different hydraulic fluid pressures, which, in combination with customized grooves, provide variable motor balance, thereby improving the mechanical and volumetric efficiency of the device under a wider range of operating conditions.

[0012] Figure 1 is a schematic diagram of the motor system. Figure 2 is a cross-sectional schematic diagram of the motor, including an actuator in a first position. Figure 3 is a detailed view of the valve plate of the motor system. Figure 4 shows the hydraulic circuit of the motor. FIGS. 5A and 5B show the difference in fluid distribution between a motor with a closed valve and a motor with at least a partially open valve.

[0013] Now refer to Figure 1 , which shows a schematic diagram of a motor system 100 of a vehicle 102, including a motor 104 connected to a controller 112 and a motor 104 connected to one or more wheels 110 of the vehicle via a drive shaft 120. It should be understood that although Figure 1 refers to an embodiment within a vehicle, in other embodiments, the motor system 100 can be included in a different machine that generates torque for purposes other than propulsion. The motor can be an axial motor, a bent axis motor, or other motors. In one example, the motor is a hydraulic displacement motor.

[0014] When the cylinder block rotates, the pump 150 pumps pressurized hydraulic oil into the motor 104, thereby generating a certain amount of torque on the drive shaft 120. The pump 150 can be part of a hydraulic circuit that includes a regulator and valves for controlling the flow of hydraulic fluid. To increase or decrease the torque, the pressure on one side of the rotating group valve plate relative to the drive shaft 120 can be adjusted. By adjusting the pressure, the displacement of the rotating group can be increased, thereby increasing the torque, or the displacement of the rotating group can be decreased, thereby decreasing the torque.

[0015] The motor 104 can be indirectly powered by the energy storage device 106 through the pump 150. Specifically, the energy stored in the energy storage device 106 can be used to power the pump 150, and the pump 150 can power the actuator 124 of the motor 104, where the actuator 124 can adjust the balance of the valve plate to change the amount of torque transmitted on the drive shaft 120. In one example, the actuator 124 is an actuator of a valve. The energy storage device 106 can be an energy storage device configured to supply power to various components of the electrical system of the vehicle 102, including supplying current to the motor 104. The energy storage device 106 can be electrically coupled to the motor 104, the pump 150, and / or the controller 112. The controller 112 can adjust the power supplied by the energy storage device 106 to the bent axis piston motor 104 to increase or decrease the speed of the vehicle 102 through the actuator 124. In some examples, the energy storage device 106 can be omitted, and the pump 150 and other components can be hydraulically driven.

[0016] The controller 112 can include a processor 140 and a memory 142. The memory 142 can store instructions that, when executed by the processor, can cause the controller 112 to perform various methods, control strategies, diagnostic techniques, etc. For example, various methods can include adjusting the pressure applied to the valve plate in contact with the cylinder block piston relative to the drive shaft 120 to change the amount of torque applied to the drive shaft 120 (e.g., in response to an operator's input). The processor 140 can include a microprocessor unit and / or other types of circuits. The memory 142 can include known data storage media, such as random access memory, read-only memory, keep-alive memory, combinations thereof, etc. The memory 142 can include non-temporary memory.

[0017] The controller 112 can receive vehicle data and various signals from sensors disposed at different positions on the electric motor 104 and / or the vehicle 102. The sensors can include an oil temperature sensor 170, an engine speed sensor 172, one or more wheel speed sensors 174, and other sensors of the motor 104 (such as a torque sensor, a pressure sensor, etc.). The controller 112 can send control signals to one or more actuators of the motor 104 according to the operator's input and / or the signals received from the sensors. For example, the controller 112 can adjust the speed and / or torque generated on the drive shaft 120 according to the operator's input and / or the signals received from the sensors.

[0018] The motor system 100 may include one or more input devices 114. For example, the input device 114 may include vehicle pedals (such as an accelerator pedal), control levers (such as a forward-neutral-reverse (FNR) lever), one or more buttons, or similar types of controls, or combinations thereof. In one example, the FNR joystick is used to operate the vehicle in the forward or reverse direction, and the accelerator pedal is used to increase or decrease the vehicle speed. The input device 114 can generate a torque adjustment request and a desired driving direction (forward or reverse direction) based on the driver's input. For example, when the controller receives a speed adjustment request, the output speed of the motor 104 can be increased accordingly.

[0019] The motor system 100 can automatically switch the drive mode as needed. For example, an operator can request a change in the speed of the forward or reverse drive mode, and the controller 112 can command the motor 104 to increase the speed and automatically switch between one or more drive ranges associated with different drive modes as needed.

[0020] Now refer to Figure 2 , which shows a detailed schematic diagram of the motor device 200, which can be a non-limiting example of the motor 104 referred to above with reference to Figure 1 . In the Figure 2 example, the motor device 200 is a bent-axis motor unit (BAU) 200. As described above, the valves and valve plates of the motor device 200 can be included in a bent-axis motor or an axial motor. The shaft system 290 shown in the figure includes three axes, namely, the x-axis parallel to the horizontal direction, the y-axis parallel to the vertical direction, and the z-axis normal to the x-axis and the y-axis respectively.

[0021] The BAU 200 includes a BAU rotating group 202, which is installed inside the housing 201 of the BAU 200. The BAU rotating group 202 includes a cylinder block 203, and there are a plurality of pistons 206 inside the cylinder block 203. The pistons 206 slide in the corresponding plurality of chambers 217 of the cylinder block 203. When the BAU rotating group 202 rotates, the pistons 206 can rotate the flange 207 hydraulically. The center pin 210 can include a fixed spring 213, and this spring can provide a force between the cylinder block 203, the valve plate 208, the center pin 210, and the shaft.

[0022] The BAU rotating group 202 can act as a transmission, and provide variable output torque on the drive shaft according to the pressure applied to both sides of the fixed-angle valve plate 208, so that the movement range of the pistons 206 is set by the fixed inclination angle between the valve plate 208 of the BAU rotating group 202 and the drive shaft 204. The pistons 206 can be connected to the flange 207 through a universal joint or a spherical joint 205.

[0023] The flange 207 can be mechanically coupled to the drive shaft 204 by a plurality of roller bearings 209 installed in respective bearing housings 211, such that when the flange 207 rotates via the rotary piston 206, the rotation of the flange 207 is transmitted to the drive shaft 204. The BAU 200 can include a timing gear 215 to synchronize the piston barrel with the shaft. The housing 201 can include a shaft seal to seal the BAU 200 around the surface of the drive shaft 204.

[0024] The chamber 217 is in fluid communication with a hydraulic system, and the hydraulic fluid fills the chamber 217 and the intermediate conduit. The chamber can be connected to a hydraulic conduit, and the hydraulic fluid circulates between the hydraulic system and the chamber 217 through the hydraulic conduit. During the operation of the bent-axis piston motor device 200, the hydraulic system can direct the hydraulic fluid to the chamber 217 through an inlet hydraulic circuit and receive the hydraulic fluid back from the chamber 217 through an outlet hydraulic circuit.

[0025] In one example, the fixed-angle valve plate 208 is connected to a hydraulic circuit through an air inlet 230. The valve can control the fluid flowing into and out of the inlet 230. The inlet passage 232 can direct the fluid from the inlet port 230 to the groove of the valve plate 208. The inlet passage 232 can bifurcate and direct the fluid to the first groove 236 and the second groove 242. The first connection passage 234 can fluidly couple the inlet passage 232 with the first groove 236. The second connection passage 238 can fluidly connect the inlet passage 232 with the second groove 242. The geometry of the fixed-angle valve plate 208 can be adjusted to change the pressure on at least one side of the fixed-angle valve plate 208. That is, the fixed-angle valve plate 208 can include a first side opposite to the piston and grooves fluidly connected to the air inlet 230, and a second side opposite to the cylinder block 203. Adjusting the pressure on the second side through the hydraulic circuit can adjust the efficiency of the motor device 200.

[0026] Now look at Figure 3 , which shows an embodiment 300 of the valve plate 310. The valve plate 310 can be Figure 2 a non-limiting example of the valve plate 208 in Figure 2 . The embodiment 300 can show the first side 302 of the valve plate 310, which can interact with one or more pistons (such as the piston 206 in Figure 2 ). The valve plate 310 can include a plurality of openings, including a central opening 320, a first opening 322, and a second opening 324. The first side 302 of the valve plate can face away from

[0027] The first and second openings can surround the central opening 320. The first opening 322 and the second opening 324 can be the same in size and shape and mirror each other about the Y axis. The first opening 322 can be rectangular. The second opening 324 can be rectangular. In one example, the first opening 322 and the second opening 324 can be bean-shaped or kidney-shaped. That is, the first opening 322 and the second opening 324 can be arcuate, following the curvature of the valve plate 310.

[0028] The first opening 322 can be located between the first groove 236 and the second groove 242. The first groove 236 can be located between the first opening 322 and the central opening 320. The second groove 242 can be located between the first opening 322 and the outer edge 346 of the valve plate 310. The first groove 236 and the second groove 242 can be curved and match the curvature of the central opening 320, the first opening 322, and the outer edge 346. In one example, the cross-section of the groove can be semi-circular.

[0029] The valve plate 310 can further include a third groove 336 and a fourth groove 342. The third groove 336 can be the same as the first groove 236. The fourth groove can be the same as the second groove 242. The third groove 336 can be located between the central opening 320 and the second opening 324. The fourth groove 342 is located between the second opening 324 and the outer edge 346. In one example, the first groove 236 and the third groove 336 are a first pair, and the second groove 242 and the fourth groove 342 are a second pair.

[0030] The inlet passage 232 can be in fluid connection with each of the third groove 336 and the fourth groove 342. Thus, the first, second, third, and fourth grooves can control the pressure on the valve plate 310, thereby improving its mechanical and fluid efficiency.

[0031] The size of the groove can be at least partially based on the corresponding distributed arc length. For example, the arc lengths of the first groove 236 and the second groove 242 can be shorter than the first distributed arc length 381. The arc lengths of the third groove 336 and the fourth groove 342 can be shorter than the second distributed arc length 382. The first distributed arc length 381 can be the same as the second distributed arc length 382.

[0032] In one example, the length of the first groove 236 may be less than the length of the second groove 242. The ratio of the length of the first groove 236 to the corresponding first distributed arc length can be equal to the ratio of the length of the second groove 242 to the corresponding first distributed arc length. Additionally, different ratios can also be employed.

[0033] In one example, each groove passes through 5% to 50% of the corresponding circumference of the valve plate. The length and / or width of the groove can be adjusted according to different operating conditions to achieve the desired valve plate balance. Depending on the intended application of the motor, the imbalance tolerance can be adjusted by adjusting the size, shape, length, and number of the grooves. The valve can be configured to adjust the imbalance tolerance and restore balance during operation, so that the motor is not limited to only the parameters set during manufacturing.

[0034] In some examples, additionally or alternatively, the inlet passage can be divided into two passages, one being a first inlet passage connected to the first and second grooves, and the other being a second inlet passage connected to the third and fourth grooves. The valve can be configured to direct fluid to only the first inlet passage or the second inlet passage depending on the position of the valve.

[0035] In a further embodiment, additionally or alternatively, the intake passage can be divided into four passages, a first intake passage connected only to the first groove, a second intake passage connected only to the second groove, a third intake passage connected only to the third groove, and a fourth intake passage connected only to the fourth groove. Thus, the combination of the valve, the inlet passage, and the grooves can work together to adjust the variable balance of the valve plate and reduce power loss.

[0036] Now referring to Figure 4 , a fluid circuit 400 is shown in the figure. The fluid circuit 400 can be a fluid circuit connected to the motor 104 of Figure 1 or the BAU200 of Figure 2 . The fluid circuit 400 includes a valve 410 fluidly connected to an inlet 230 through a connection passage 412. In one example, the connection passage 412 is directly fluidly connected to the inlet port 230 and controls the fluid flow through the valve 410 to achieve the variable balance of the valve plate (such as the valve plate 310 of Figure 3 or the valve plate 208 of Figure 2 ). The inlet port 230 can be included in a fluid port manifold 430, which further includes a first outlet port 432 and a second outlet port 434. The first outlet port 432 can be fluidly coupled to a first return line 442 including a first check valve 444. The second outlet port 434 can be fluidly connected to a second return line 446 including a second check valve 448. The return lines can return fluid from the motor to the valve 410.

[0037] In some examples, as a supplement or alternative, the valve 410 may be disposed entirely within the motor. In one example, the valve 410 may be integrally arranged with the inlet port 230 and the outlet ports 432, 434. The valve 410 may include a plurality of positions configured to control the fluid flow rate to the first through fourth grooves and the fluid flow rate to the outlet ports. Additionally, the plurality of positions for controlling the fluid flow to the grooves may be variable positions, each of which is adjustable to vary the fluid flow rate to each groove. Thus, the flow rate to the first groove may be different from the flow rates to the other grooves.

[0038] Now referring to FIGS. 5A and 5B, which respectively show example fluid distributions 500 and 550 of the valve plate 208 based on valve positions. In example 500, the valve is closed, and the high-pressure fluid distribution region is shown by the diagonal pattern region 502, and the low-pressure fluid distribution region is shown by the cross pattern region 504. This may result in a heavier valve plate balance, which may not be desirable under certain operating conditions.

[0039] In example 550, the valve is open, and the high-pressure fluid distribution is shown by the diagonal pattern region 552. Due to the high-pressure fluid distribution, the valve plate balance may be lighter, which may be desirable in some cases. Thus, the addition of the valve and the grooves may provide an improvement compared to the previous example of the fluid pressure distribution with only FIG. 5A.

[0040] In one example, the valve opens when the motor speed is higher than a determined motor speed and / or when the operating pressure is less than a determined operating pressure. When the valve is open, a lighter balance may be provided, thereby improving motor efficiency. The valve and valve plate including the grooves can be used for fixed displacement motors and swashplate variable displacement motors.

[0041] The present disclosure provides support for a hydraulic displacement motor that includes a valve plate coupled to at least one piston of a cylinder block. The valve plate includes a plurality of grooves fluidly coupled to channels that include valves. A first example of the motor further includes that a first pair of the plurality of grooves are identical to each other, a second pair of the plurality of grooves are identical to each other, and the first pair is different from the second pair. A second example of the motor (optionally including the first example) further includes that the first pair includes an arc length shorter than that of the second pair. A third example of the motor, optionally including one or more of the foregoing examples, further includes that each of the plurality of grooves is arcuate and follows the curvature of a circle. A fourth example of the motor, optionally including one or more of the foregoing examples, further includes that each of the plurality of grooves traverses 5% to 50% of the corresponding circumference of the valve plate. A fifth example of the motor (optionally including one or more of the foregoing examples) further includes that the valve plate includes a central opening, a first opening, and a second opening identical to the first opening that engage at least one piston, and the plurality of grooves are disposed between the central opening, the first opening, the second opening, and an outer edge of the valve plate. A sixth example of the motor, optionally including one or more of the foregoing examples, further includes that the valve is located outside the hydraulic displacement motor. A seventh example of the motor, optionally including one or more of the foregoing examples, further includes that the hydraulic displacement motor is an axial motor or a bent-axis motor. An eighth example of the motor (optionally including one or more of the foregoing examples) further includes that the cross-sectional shape of each of the plurality of grooves is semi-circular.

[0042] The present disclosure provides further support for a fluid displacement motor, the motor including a cylinder block in which a plurality of pistons oscillate; a valve plate including a central opening through which at least one of the plurality of pistons oscillates, the valve plate being located between a first opening and a second opening; the valve plate further including a plurality of grooves, a first groove being located between the central opening and the first opening, a second groove being located between the first opening and the outer edge of the valve plate, a third groove being located between the central opening and the second opening, a fourth groove being located between the second opening and the outer edge of the valve plate, a second groove disposed between the first opening and the outer edge of the valve plate, a third groove disposed between the central opening and the second opening, and a fourth groove disposed between the second opening and the outer edge, and a valve disposed in a connection passage coupled to an air inlet of the fluid displacement motor, the valve being configured to control the flow of fluid to the plurality of grooves. A first example of the motor further includes that the first groove and the third groove are the same in size and shape, wherein the second groove and the fourth groove are the same in size and shape. A second example of the motor (optionally including the first example) further includes that the plurality of grooves are disposed on a side of the valve plate facing the cylinder block. A third example of the motor (optionally including one or more of the foregoing examples) further includes: an air inlet passage extends from the air inlet and branches to direct fluid to each of the plurality of grooves. A fourth example of the motor (optionally including one or more of the foregoing examples) further includes: the first and third grooves are different in size and shape from the second and fourth grooves. A fifth example of the motor (optionally including one or more of the foregoing examples) further includes: the arc length of the first opening is shorter than that of the first opening, and the arc length of the second opening is shorter than that of the first opening.

[0043] The present disclosure provides additional support for a fluid displacement motor that includes a cylinder block in which a plurality of pistons oscillate; a valve plate that includes a central opening through which at least one of the plurality of pistons oscillates and that is located between a first opening and a second opening; the valve plate further includes a plurality of grooves, a first groove disposed between the central opening and the first opening, a second groove disposed between the first opening and the outer edge of the valve plate, a third groove disposed between the central opening and the second opening, and a fourth groove disposed between the second opening and the outer edge, wherein the first groove is the same as the third groove, the second groove is the same as the fourth groove, and a valve disposed in a connection passage coupled to an inlet port of the fluid displacement motor, the valve being configured to control the flow of fluid to the plurality of grooves. A first example of the motor further includes each of the plurality of grooves being fluidly separated from each other. A second example of the motor (optionally including the first example) further includes: the arc lengths of the first and second grooves being less than a first fluid distribution arc. A third example of the motor (optionally including one or more of the foregoing examples) further includes: the arc lengths of the third and fourth grooves being less than a second fluid distribution arc length. A fourth example of the motor (optionally including one or more of the foregoing examples) further includes the valve plate being symmetric about a single axis.

[0044] While the various embodiments have been described above, it should be understood that these embodiments are merely examples and not limitations. It will be apparent to those skilled in the relevant art that the disclosed subject matter may be embodied in other specific forms without departing from the spirit of the subject matter. Accordingly, the above embodiments should be considered in all respects to be exemplary and not restrictive.

[0045] Note that the control and estimation routine examples contained herein can be used for a variety of powertrain and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-transitory memory and executed by a control system including a controller in conjunction with a variety of sensors, actuators, and other transmission and / or vehicle hardware. Additionally, some of the methods may be physical operations taken in the real world to change the state of a device. The specific routines described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc. As such, the various actions, operations, and / or functions illustrated may be executed in the illustrated order, may be executed in parallel, or in some cases may be omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the examples described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations, and / or functions may be repeated according to the particular strategy being used. Additionally, the actions, operations, and / or functions described may be graphically represented as code to be programmed into the non-transitory memory of a computer-readable storage medium in a vehicle and / or transmission control system, where the described actions are implemented by executing instructions in a system including a variety of hardware components in combination with an electronic controller. One or more method steps described herein may be omitted if desired.

[0046] It will be understood that the configurations and routines disclosed herein are exemplary in nature and these specific embodiments are not limiting since many variations are possible. As used herein, an element or step recited in the singular and preceded by "a" or "an" should be understood as not excluding plural of the elements or steps, unless explicitly stated to the contrary. Additionally, reference to "one embodiment" of the present invention should not be construed as excluding the existence of other embodiments that also incorporate the recited features. Moreover, unless expressly stated to the contrary, an embodiment including one element or elements having a particular property may include other elements not having that property. The terms "comprising" and "wherein" are used as pure linguistic equivalents of the terms "including" and "wherein", respectively. Additionally, the terms "first", "second", and "third", etc. are used merely as labels and are not intended to impose numerical requirements or a particular positional order on their objects.

[0047] Figure 2-5BShows an example configuration of the relative positioning of various elements. If the elements shown in the figure are in direct contact or directly coupled to each other, then in at least one example, these elements can be referred to as being in direct contact or directly coupled, respectively. Similarly, in at least one example, elements shown adjacent or contiguous to each other can be adjacent or contiguous to each other, respectively. For example, elements in face-to-face contact with each other can be referred to as face-to-face contact elements. Another example is that in at least one example, elements are placed separately from each other with only space in between and no other elements, and can be referred to as being placed separately from each other. Also, elements shown above / below each other, on opposite sides of each other, or on the left / right side of each other relative to each other can be referred to as such elements. In addition, as shown in the figure, in at least one example, the topmost element or element point can be referred to as the "top" of the element, and the bottommost element or element point can be referred to as the "bottom" of the element. The top / bottom, upper / lower, above / below used in this description can be relative to the vertical axis in the figure and are used to describe the relative positioning of the various elements in the figure with respect to each other. Thus, in one example, an element shown above other elements is vertically positioned above the other elements. As another example, the shapes of the elements depicted in the figure can be referred to as having these shapes (e.g., circular, straight, planar, curved, round, chamfered, beveled, or similar shapes). In addition, in at least one example, elements shown intersecting each other can be referred to as intersecting elements or intersecting each other. Further, in one example, an element shown inside or outside another element can also be referred to as an intersecting element.

[0048] This written description uses examples to disclose the present invention, including the best mode, and enables one of ordinary skill in the relevant art to practice the present invention, including making and using any device or system and performing any incorporated method. The scope of the patent for the present invention is defined by the claims and may include other examples that occur to one of ordinary skill in the art. If the structural elements of these other embodiments do not differ from the literal language of the claims, or if these other embodiments include equivalent structural elements that do not differ materially from the literal language of the claims, then these other embodiments are within the scope of the claims.

Claims

1. A hydraulic displacement motor, characterized in that: The hydraulic displacement motor comprises A valve plate is connected to at least one piston of the cylinder body, and the valve plate includes a plurality of grooves, and the plurality of grooves are fluidly connected to a channel including a valve.

2. The hydraulic displacement motor according to claim 1, characterized in that A first pair of grooves among the plurality of grooves are identical to each other, a second pair of grooves among the plurality of grooves are identical to each other, and the first pair of grooves and the second pair of grooves are different from each other.

3. The hydraulic displacement motor according to claim 2, characterized in that The arc length of the first pair of grooves is shorter than the arc length of the second pair of grooves.

4. The hydraulic displacement motor according to claim 1, characterized in that Each of the plurality of grooves is arc-shaped and is arranged along the arc of the same circle.

5. The hydraulic displacement motor according to claim 1, characterized in that Each of the plurality of grooves penetrates 5% to 50% of a corresponding circumference of the valve plate.

6. The hydraulic displacement motor according to claim 1, characterized in that The valve plate includes a central opening engaged with at least one piston, a first opening and a second opening identical to the first opening, wherein the plurality of grooves are arranged between the central opening, the first opening, the second opening and an outer edge of the valve plate.

7. The hydraulic displacement motor of claim 1, wherein The valve is located external to the hydraulic displacement motor.

8. The hydraulic displacement motor of claim 1, wherein The hydraulic displacement motor is an axial motor or a bent axis motor.

9. The hydraulic displacement motor according to claim 1, characterized in that The cross-sectional shape of each of the plurality of grooves is semicircular.

10. A fluid displacement motor, characterized in that: The fluid displacement motor includes a cylinder block including a plurality of pistons oscillating therein; A valve plate, comprising a central opening, through which at least one of the plurality of pistons swings between a first opening and a second opening, the valve plate further comprising a plurality of grooves, a first groove of the plurality of grooves being arranged between the central opening and the first opening, a second groove of the plurality of grooves being arranged between the first opening and an outer edge of the valve plate, a third groove of the plurality of grooves being arranged between the central opening and the second opening, and a fourth groove of the plurality of grooves being arranged between the second opening and an outer edge of the valve plate; as well as A valve is installed in the connecting passage connected to the air inlet of the fluid displacement motor, and the valve is used to control the flow of fluid to the plurality of grooves.

11. The fluid displacement motor of claim 10, wherein The first groove and the third groove have the same size and shape, and the second groove and the fourth groove have the same size and shape.

12. The fluid displacement motor of claim 10, wherein The plurality of grooves are located on a side of the valve plate facing the cylinder body.

13. The fluid displacement motor of claim 10, wherein: An air inlet passage extends from the air inlet and branches to allow fluid to flow to each of the plurality of grooves.

14. The fluid displacement motor of claim 10, wherein The size and shape of the first and third grooves are different from the size and shape of the second and fourth grooves.

15. The fluid displacement motor of claim 10, wherein The arc length of the first opening is shorter than that of the first opening, and the arc length of the second opening is shorter than that of the first opening.

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