Variable plunger pump

Abstract

The utility model provides a variable plunger pump. The variable plunger pump comprises a first oil tank; the swash plate is arranged on the plunger pump body, and an oil suction port of the plunger pump body is connected with an oil tank; the swash plate adjusting mechanism comprises a piston, a first piston cavity and a second piston cavity, the first piston cavity and the second piston cavity are located on the two opposite sides of the piston respectively, and the piston is connected with the swash plate to drive the swash plate to swing; a first oil port and a second oil port of the reversing valve are respectively connected with the first piston cavity and the second piston cavity; a throttling valve inlet of the throttling valve is used for allowing control oil F to flow in, a throttling valve outlet of the throttling valve is connected with the second oil tank, and a first throttling opening and a second throttling opening of the throttling valve are connected with a third oil opening and a fourth oil opening of the reversing valve respectively; the control unit is electrically connected with the reversing valve and the throttling valve, so that the problem that in the prior art, stepless adjustment of the displacement speed of a variable displacement piston pump cannot be achieved is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of plunger pump control, in particular to a variable plunger pump. Background Art

[0002] The structure of the variable piston pump in the prior art is mostly a swash plate type variable piston pump, which changes the swash plate angle according to the working conditions and then changes the displacement of the piston pump to meet the flow requirements of the hydraulic system. However, it is impossible to achieve real-time adjustment of the displacement speed of the piston pump, thus limiting the application scenarios of the piston pump.

[0003] For example, some plunger pumps use n high-speed switching valves to form a control valve group. The flow of hydraulic oil is controlled by controlling the number of high-speed switching valves in the control valve group that are opened, thereby controlling the displacement speed of the plunger pump. Therefore, its adjustment method is step adjustment rather than stepless adjustment. In addition, since the control valve group has a large number of parts and a relatively complex structure, there are problems such as high production cost and poor reliability. Utility Model Content

[0004] The main purpose of the utility model is to provide a variable piston pump to solve the problem that the displacement speed of the variable piston pump in the prior art cannot be infinitely adjusted.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the utility model, a variable piston pump is provided, comprising: a first oil tank; a piston pump body and a swash plate arranged on the piston pump body, the oil suction port of the piston pump body is connected to the oil tank; a swash plate adjustment mechanism, the swash plate adjustment mechanism comprises a piston and a first piston chamber and a second piston chamber respectively located on opposite sides of the piston, the piston is connected to the swash plate to drive the swash plate to swing; a reversing valve, the first oil port and the second oil port of the reversing valve are respectively connected to the first piston chamber and the second piston chamber; a throttle valve, the throttle valve inlet of the throttle valve is used for supplying control oil F to flow in, the throttle valve outlet of the throttle valve is connected to the second oil tank, the first throttle port and the second throttle port of the throttle valve are respectively connected to the third oil port and the fourth oil port of the reversing valve; a control unit, the control unit is electrically connected to the reversing valve and the throttle valve.

[0006] Furthermore, the variable piston pump also includes an angle detection component, which is arranged on the piston pump body and connected to the swash plate. The angle detection component is electrically connected to the control unit to detect the swing angle of the swash plate and feed back the detection result to the control unit.

[0007] Furthermore, the angle detection component is a rotation angle sensor.

[0008] Furthermore, the swash plate adjustment mechanism includes a first cylinder body and a second cylinder body arranged at an interval, the first piston chamber and the second piston chamber are respectively located in the first cylinder body and the second cylinder body, and the two ends of the piston are respectively movably inserted in the first cylinder body and the second cylinder body to push the piston to move according to the pressure of the control oil in the first piston chamber and the pressure of the control oil in the second piston chamber.

[0009] Furthermore, the reversing valve is a three-position four-way solenoid valve.

[0010] Further, the reversing valve includes: a left-position working state, when the reversing valve is in the left-position working state, the first oil port and the fourth oil port are connected, and the second oil port and the third oil port are connected; a middle-position working state, when the reversing valve is in the middle-position working state, any two of the first oil port, the second oil port, the third oil port and the fourth oil port are not connected; a right-position working state, when the reversing valve is in the right-position working state, the first oil port and the third oil port are connected, and the second oil port and the fourth oil port are connected.

[0011] Further, the reversing valve includes: a main valve body, on which a first oil port, a second oil port, a third oil port and a fourth oil port are arranged; a shifting valve core assembly, which is movably arranged in the main valve body to enable the reversing valve to switch between a left-position working state, a middle-position working state and a right-position working state; a first transposition driving component and a second transposition driving component, which are both driven and connected to the transposition valve core assembly, and a control unit is electrically connected to the first transposition driving component and the second transposition driving component to control the first transposition driving component and / or the second transposition driving component to drive the transposition valve core assembly to move.

[0012] Furthermore, the throttle valve is an electromagnetic throttle valve.

[0013] Furthermore, the throttle valve includes a throttle body and a throttle valve core. The throttle valve body is provided with an intermediate cavity and a throttle valve inlet, a first throttle port, a second throttle port and a throttle valve outlet connected to the intermediate cavity. The throttle valve core is movably arranged in the intermediate cavity to adjust the flow area of ​​the first throttle port and the flow area of ​​the second throttle port.

[0014] Further, the throttle valve includes a throttle valve core driving component, the throttle valve core driving component is connected to the throttle valve core driving, and the control unit is electrically connected to the throttle valve core driving component to control the throttle valve core driving component to drive the throttle valve core to move.

[0015] Applying the technical solution of the utility model, the variable piston pump of the utility model comprises: a first oil tank; a plunger pump body and a swash plate arranged on the plunger pump body, the oil suction port of the plunger pump body is connected to the oil tank; a swash plate adjustment mechanism, the swash plate adjustment mechanism comprises a piston and a first piston chamber and a second piston chamber respectively located on opposite sides of the piston, the piston is connected to the swash plate to drive the swash plate to swing; a reversing valve, the first oil port and the second oil port of the reversing valve are respectively connected to the first piston chamber and the second piston chamber; a throttle valve, the throttle valve inlet of the throttle valve is used for supplying control oil F to flow in, the throttle valve outlet of the throttle valve is connected to the second oil tank, the first throttle port and the second throttle port of the throttle valve are respectively connected to the third oil port and the fourth oil port of the reversing valve; a control unit, the control unit is electrically connected to the reversing valve and the throttle valve. In this way, the variable piston pump of the utility model can be equipped with a variable speed adjustment function according to user needs. The flow of the first throttle port and the second throttle port of the throttle valve is controlled by the control unit, thereby controlling the flow of the control oil F flowing into and out of the swash plate adjustment mechanism, thereby realizing real-time stepless adjustment of the variable speed of the piston pump body, expanding the application scenarios of the variable piston pump, having the advantage of reducing the raw material cost and management cost required for manufacturing, and solving the problem that the displacement speed of the variable piston pump in the prior art cannot be steplessly adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0017] Figure 1 A schematic structural diagram of a control system of an embodiment of a variable displacement piston pump according to the utility model is shown;

[0018] Figure 2 A signal feedback diagram of a control system of a variable piston pump of the utility model is shown.

[0019] The above drawings include the following reference numerals:

[0020] 1. First fuel tank;

[0021] 2. Plunger pump body;

[0022] 3. Swash plate adjustment mechanism; 30. Piston; 31. First piston chamber; 32. Second piston chamber;

[0023] 4. reversing valve; 41. first oil port; 42. second oil port; 43. third oil port; 44. fourth oil port; 401. first transposition drive component; 402. second transposition drive component;

[0024] 5. Control unit;

[0025] 6. throttle valve; 61. first throttle port; 62. second throttle port; 63. throttle valve inlet; 64. throttle valve outlet; 601. throttle valve body; 602. throttle valve core; 603. throttle valve core driving component;

[0026] 7. Angle detection components;

[0027] 8. Swash plate;

[0028] 9. Second fuel tank. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present utility model will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] like Figure 1 As shown, the utility model provides a variable piston pump, comprising: a first oil tank 1; a piston pump body 2 and a swash plate 8 arranged on the piston pump body 2, the oil suction port of the piston pump body 2 is connected to the first oil tank 1; a swash plate adjustment mechanism 3, the swash plate adjustment mechanism 3 comprises a piston 30 and a first piston cavity 31 and a second piston cavity 32 respectively located on opposite sides of the piston 30, the piston 30 is connected to the swash plate 8 to drive the swash plate 8 to swing; a reversing valve 4, the first oil port 41 and the second oil port 42 of the reversing valve 4 are respectively connected to the first piston cavity 31 and the second piston cavity 32; a throttle valve 6, the throttle valve inlet 63 of the throttle valve 6 is used for supplying control oil F to flow in, the throttle valve outlet 64 of the throttle valve 6 is connected to the second oil tank 9, the first throttle port 61 and the second throttle port 62 of the throttle valve 6 are respectively connected to the third oil port 43 and the fourth oil port 44 of the reversing valve 4; a control unit 5, the control unit 5 is electrically connected to the reversing valve 4 and the throttle valve 6.

[0031] In this way, the variable piston pump of the utility model can be equipped with a variable speed adjustment function according to user needs. The flow of the first throttle port 61 and the second throttle port 62 of the throttle valve 6 is controlled by the control unit 5, thereby controlling the flow of the control oil F flowing into and out of the swash plate adjustment mechanism 3, thereby realizing real-time stepless adjustment of the variable speed of the piston pump body 2, expanding the application scenarios of the variable piston pump, having the advantages of reducing the raw material cost and management cost required for manufacturing, and solving the problem that the displacement speed of the variable piston pump in the prior art cannot be steplessly adjusted.

[0032] Optionally, the variable displacement piston pump of the utility model can be used in an open hydraulic pump or a closed hydraulic pump.

[0033] like Figure 1As shown, the variable piston pump also includes an angle detection component 7, which is arranged on the piston pump body 2 and connected to the swash plate 8. The angle detection component 7 is electrically connected to the control unit 5 to detect the swing angle of the swash plate 8 and feed back the detection result to the control unit 5.

[0034] In this way, the angle detection component 7 sends the detection result to the control unit 5 through the feedback signal I4, and the control unit 5 revises the variable speed of the plunger pump body 2 in real time according to the feedback signal I4, so that the variable plunger pump of the utility model has the advantage of precise control.

[0035] like Figure 1 As shown, the angle detection component is a rotation angle sensor.

[0036] like Figure 1 As shown, the swash plate adjustment mechanism 3 includes a first cylinder body and a second cylinder body that are spaced apart, a first piston chamber 31 and a second piston chamber 32 are respectively located in the first cylinder body and the second cylinder body, and both ends of the piston 30 are respectively movably inserted in the first cylinder body and the second cylinder body to push the piston 30 to move according to the pressure of the control oil in the first piston chamber 31 and the pressure of the control oil in the second piston chamber 32.

[0037] The reversing valve 4 of the utility model is a three-position four-way solenoid valve.

[0038] like Figure 1 As shown, the reversing valve 4 includes: a left working state, when the reversing valve 4 is in the left working state, the first oil port 41 is connected to the fourth oil port 44, and the second oil port 42 is connected to the third oil port 43; a middle working state, when the reversing valve 4 is in the middle working state, any two of the first oil port 41, the second oil port 42, the third oil port 43 and the fourth oil port 44 are not connected; a right working state, when the reversing valve 4 is in the right working state, the first oil port 41 is connected to the third oil port 43, and the second oil port 42 is connected to the fourth oil port 44.

[0039] like Figure 1 As shown, the reversing valve 4 includes: a main valve body, on which a first oil port 41, a second oil port 42, a third oil port 43 and a fourth oil port 44 are provided; a shift valve core assembly, which is movably arranged in the main valve body to enable the reversing valve 4 to switch between a left-position working state, a middle-position working state and a right-position working state; a first shift drive component 401 and a second shift drive component 402, which are both driven and connected to the shift valve core assembly, and a control unit 5 is electrically connected to the first shift drive component 401 and the second shift drive component 402 to control the first shift drive component 401 and / or the second shift drive component 402 to drive the shift valve core assembly to move.

[0040] Specifically, the first transposition driving component 401 and the second transposition driving component 402 both include an electromagnetic coil and a spring.

[0041] The throttle valve 6 of the present invention is an electromagnetic throttle valve.

[0042] like Figure 1 As shown, the throttle valve 6 includes a throttle body 601 and a throttle valve core 602. The throttle valve body 601 is provided with an intermediate cavity and a throttle valve inlet 63, a first throttle port 61, a second throttle port 62 and a throttle valve outlet 64 connected to the intermediate cavity. The throttle valve core 602 is movably arranged in the intermediate cavity to adjust the flow area of ​​the first throttle port 61 and the flow area of ​​the second throttle port 62.

[0043] like Figure 1 As shown, the throttle valve 6 includes a throttle valve core driving component 603, which is drivingly connected to the throttle valve core 602, and the control unit 5 is electrically connected to the throttle valve core driving component 603 to control the throttle valve core driving component 603 to drive the throttle valve core 602 to move.

[0044] Specifically, the throttle valve core driving component 603 includes an electromagnetic coil and a spring.

[0045] In this way, the flow rates of the first throttle port 61 and the second throttle port 62 are controlled in real time by the signal I3 emitted by the control unit 5, and there is a linear relationship between the flow rates of the first throttle port 61 and the second throttle port 62 and the signal I3, so that real-time stepless adjustment of the variable speed of the plunger pump body 2 can be achieved. Therefore, the variable plunger pump of the utility model has the advantages of stable output flow and small impact.

[0046] like Figure 1 As shown, the oil flow process of the control system of the variable piston pump of the utility model is as follows:

[0047] (1) The plunger pump body 2 operates to suck oil from the first oil tank 1, and after passing through the plunger pump suction port S, the oil is pressurized and output to the plunger pump outlet P. The displacement of the plunger pump body 2 is controlled by the swing of the swash plate 8;

[0048] (2) The control oil F flows into the third oil port 43 of the reversing valve 4 after passing through the throttle valve inlet 63 and the first throttle port 61 of the throttle valve 6;

[0049] (3) When the control unit 5 sends the control signal I2 to the reversing valve 4, the reversing valve 4 switches to the right working state, and the control oil F flows from the third oil port 43 through the first oil port 41 into the first piston chamber 31 of the swash plate adjustment mechanism 3 to push the piston 30 to move toward the second piston chamber 32 of the swash plate adjustment mechanism 3, thereby driving the swash plate 8 to swing, so as to control the plunger pump body 2 to change the variable.

[0050] (4) The oil in the second piston chamber 32 will flow into the second oil port 42 of the reversing valve 4, and then flow into the second throttle port 62 of the throttle valve 6 through the fourth oil port 44 of the reversing valve 4, and finally flow from the throttle valve outlet 64 of the throttle valve 6 to the second oil tank 9.

[0051] like Figure 1 and Figure 2 As shown, the signal control process of the control system of the variable piston pump of the utility model is as follows:

[0052] (1) When the user inputs the setting signal I0 to the control unit 5, the control unit 5 first outputs the signal I1 or the signal I2 to control the reversing valve 4 to be in the left working state or the right working state; then the control unit 5 outputs the signal I3 to the throttle valve 6 to control the flow of the first throttle port 61 and the second throttle port 62 of the throttle valve 6; at the same time, the variable speed of the swash plate 8 is monitored in real time through the angle detection component 7, and the angular velocity signal measured by the angle detection component 7 is converted into a signal I4 and output to the control unit 5.

[0053] (2) The throttle valve 6 adjusts the flow of the first throttle port 61 and the second throttle port 62 in real time under the control of the signal I3 of the control unit 5, thereby controlling the flow in / out of the first piston chamber 31 and the second piston chamber 32. The flow of the first throttle port 61 and the second throttle port 62 is linearly related to the signal I3, thereby realizing stepless regulation of the variable speed of the plunger pump body 2.

[0054] (3) For example, the control unit 5 outputs a signal I2, and the reversing valve is in the right working state; when the variable speed setting signal I0 is input to the control unit 5, the control unit 5 processes and outputs a signal I3 to the throttle valve 6, so as to adjust the flow of the first throttle port 61 and the second throttle port 62 in real time, thereby adjusting the flow of the control oil F flowing into the first piston chamber 31 of the swash plate adjustment mechanism 3, and adjusting the flow of the control oil flowing out of the second piston chamber 32 of the swash plate adjustment mechanism 3, thereby realizing stepless adjustment of the variable speed of the plunger pump body 2; the variable speed of the swash plate 8 is sent to the control unit 5 by the feedback signal I4 of the angle detection component 7, and the control unit 5 calculates the deviation between the setting signal I0 and the feedback signal I4, and then revises the signal I3 in real time (PID adjustment is performed according to the deviation, and a PWM signal, i.e., signal I3, is output according to the result of the PID adjustment), and then the revised signal I3 adjusts the flow of the first throttle port 61 and the second throttle port 62 in real time, thereby achieving the purpose of real-time control of the variable speed of the plunger pump body 2.

[0055] From the above description, it can be seen that the above embodiments of the utility model achieve the following technical effects:

[0056] The variable piston pump of the utility model comprises: a first oil tank 1; a piston pump body 2 and a swash plate 8 arranged on the piston pump body 2, the oil suction port of the piston pump body 2 is connected to the first oil tank 1; a swash plate adjustment mechanism 3, the swash plate adjustment mechanism 3 comprises a piston 30 and a first piston cavity 31 and a second piston cavity 32 respectively located on opposite sides of the piston 30, the piston 30 is connected to the swash plate 8 to drive the swash plate 8 to swing; a reversing valve 4, the first oil port 41 and the second oil port 42 of the reversing valve 4 are respectively connected to the first piston cavity 31 and the second piston cavity 32; a throttle valve 6, the throttle valve inlet 63 of the throttle valve 6 is used for supplying control oil F to flow in, the throttle valve outlet 64 of the throttle valve 6 is connected to the second oil tank 9, the first throttle port 61 and the second throttle port 62 of the throttle valve 6 are respectively connected to the third oil port 43 and the fourth oil port 44 of the reversing valve 4; a control unit 5, the control unit 5 is electrically connected to the reversing valve 4 and the throttle valve 6. In this way, the variable piston pump of the utility model can be equipped with a variable speed adjustment function according to user needs. The flow of the first throttle port 61 and the second throttle port 62 of the throttle valve 6 is controlled by the control unit 5, thereby controlling the flow of the control oil F flowing into and out of the swash plate adjustment mechanism 3, thereby realizing real-time stepless adjustment of the variable speed of the piston pump body 2, expanding the application scenarios of the variable piston pump, having the advantages of reducing the raw material cost and management cost required for manufacturing, and solving the problem that the displacement speed of the variable piston pump in the prior art cannot be steplessly adjusted.

[0057] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0058] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0059] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0060] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0061] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0062] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A variable displacement piston pump, characterized in that: include: A first fuel tank (1); A plunger pump body (2) and a swash plate (8) arranged on the plunger pump body (2), wherein the oil suction port of the plunger pump body (2) is connected to the first oil tank (1); A swash plate adjustment mechanism (3), the swash plate adjustment mechanism (3) comprising a piston (30) and a first piston chamber (31) and a second piston chamber (32) respectively located on opposite sides of the piston (30), the piston (30) being connected to the swash plate (8) to drive the swash plate (8) to swing; A reversing valve (4), wherein a first oil port (41) and a second oil port (42) of the reversing valve (4) are respectively connected to the first piston chamber (31) and the second piston chamber (32); a throttle valve (6), wherein a throttle valve inlet (63) of the throttle valve (6) is used for supplying control oil F, a throttle valve outlet (64) of the throttle valve (6) is connected to a second oil tank (9), and a first throttle port (61) and a second throttle port (62) of the throttle valve (6) are respectively connected to a third oil port (43) and a fourth oil port (44) of the reversing valve (4); A control unit (5), wherein the control unit (5) is electrically connected to the reversing valve (4) and the throttle valve (6).

2. The variable displacement piston pump according to claim 1, characterized in that: The variable piston pump also includes an angle detection component (7), which is arranged on the piston pump body (2) and connected to the swash plate (8). The angle detection component (7) is electrically connected to the control unit (5) to detect the swing angle of the swash plate (8) and feed back the detection result to the control unit (5).

3. The variable displacement piston pump according to claim 2, characterized in that: The angle detection component is a rotation angle sensor.

4. The variable displacement piston pump according to claim 1, characterized in that: The swash plate adjustment mechanism (3) comprises a first cylinder body and a second cylinder body which are arranged at an interval, wherein the first piston chamber (31) and the second piston chamber (32) are respectively located in the first cylinder body and the second cylinder body, and the two ends of the piston (30) are respectively movably inserted in the first cylinder body and the second cylinder body to push the piston (30) to move according to the pressure of the control oil in the first piston chamber (31) and the pressure of the control oil in the second piston chamber (32).

5. The variable displacement piston pump according to claim 1, characterized in that: The reversing valve (4) is a three-position four-way solenoid valve.

6. The variable displacement piston pump according to claim 1 or 5, characterized in that: The reversing valve (4) comprises: A left-position working state, when the reversing valve (4) is in the left-position working state, the first oil port (41) is connected to the fourth oil port (44), and the second oil port (42) is connected to the third oil port (43); a neutral working state, when the reversing valve (4) is in the neutral working state, any two of the first oil port (41), the second oil port (42), the third oil port (43) and the fourth oil port (44) are not connected; Right working state: when the reversing valve (4) is in the right working state, the first oil port (41) is connected to the third oil port (43), and the second oil port (42) is connected to the fourth oil port (44).

7. The variable displacement piston pump according to claim 6, characterized in that: The reversing valve (4) comprises: A main valve body, wherein the main valve body is provided with the first oil port (41), the second oil port (42), the third oil port (43) and the fourth oil port (44); a shift valve core assembly, the shift valve core assembly being movably arranged in the main valve body so as to enable the reversing valve (4) to switch between the left working state, the middle working state and the right working state; A first transposition drive component (401) and a second transposition drive component (402), wherein the first transposition drive component (401) and the second transposition drive component (402) are both drive-connected to the transposition valve core assembly, and the control unit (5) is electrically connected to the first transposition drive component (401) and the second transposition drive component (402) to control the first transposition drive component (401) and / or the second transposition drive component (402) to drive the transposition valve core assembly to move.

8. The variable displacement piston pump according to claim 1, characterized in that: The throttle valve (6) is an electromagnetic throttle valve.

9. The variable displacement piston pump according to claim 1 or 8, characterized in that: The throttle valve (6) comprises a throttle valve body (601) and a throttle valve core (602); the throttle valve body (601) is provided with an intermediate cavity and a throttle valve inlet (63) connected to the intermediate cavity, a first throttle port (61), a second throttle port (62) and a throttle valve outlet (64); the throttle valve core (602) is movably arranged in the intermediate cavity to adjust the flow area of ​​the first throttle port (61) and the flow area of ​​the second throttle port (62).

10. The variable displacement piston pump according to claim 9, characterized in that: The throttle valve (6) comprises a throttle valve core driving component (603), the throttle valve core driving component (603) is drivingly connected to the throttle valve core (602), and the control unit (5) is electrically connected to the throttle valve core driving component (603) to control the throttle valve core driving component (603) to drive the throttle valve core (602) to move.

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