Variable displacement mechanism of two-stage variable displacement oil pump

Abstract

The utility model relates to the technical field of oil pumps, and discloses a two-stage variable displacement oil pump variable displacement mechanism which comprises a valve body and an electromagnetic valve, and a first oil port and a second oil port which are communicated with an engine lubrication main oil duct and an electromagnetic valve feedback oil duct are formed in the two ends of the valve body respectively. The middle of the valve body is provided with a third oil port and a fourth oil port which are communicated with an oil pump variable discharge pressure cavity and an oil pan respectively, and the third oil port is formed in the side close to the first oil port. The combined valve core is arranged in the valve body, and the electromagnetic valve is combined to control the oil pressure of the feedback oil duct, so that the displacement of the oil pump is accurately adjusted, and the pressure of the oil is stably controlled; the electromagnetic valve adjusts the oil pressure of the feedback oil duct according to an instruction when the working condition of an engine changes, so that the combined valve core moves; communication or blocking of the third oil port and the first oil port is accurately controlled, pressure oscillation caused by sudden pressure change of the oil cavity is effectively avoided, and stable operation of an engine lubricating system is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of oil pump technology, specifically to a two-stage variable displacement oil pump variable displacement mechanism. Background Technology

[0002] The variable displacement oil pump technology commonly used in engines today is based on a vane-type positive displacement pump. This pump, combined with a switching solenoid valve or a proportional solenoid valve, achieves two-stage or fully variable displacement function through an oil circuit feedback system and an internal variable displacement mechanism, thereby meeting the engine's requirements for oil pressure and flow under different operating conditions.

[0003] The existing Chinese patents with application numbers 201510324460 and 202021584145 are both blade-type two-stage pressure regulating oil pumps that use a pilot-operated solenoid valve single-chamber feedback mechanism. The characteristic of the pilot valve used in this mechanism is that the first oil chamber and the second oil chamber are on the same end. In low-pressure mode, the solenoid valve controls the second oil chamber to be connected to the oil circuit and works together with the first oil chamber. The pressure of the two oil chambers works together on the end face of the pilot valve to compress the spring and realize the variable discharge function.

[0004] Because the aforementioned mechanism requires two oil chambers to jointly drive the compression spring of the displacement mechanism in low-pressure mode, and the spring compression is relatively large, while the oil pressure of the oil chamber controlled by the solenoid valve is affected by the displacement mechanism, under transient conditions, the sudden change in oil pressure in the two chambers can easily cause unstable oil pressure control and pressure oscillation, leading to a series of NVH problems in the engine lubrication system. In addition, under low-temperature cold start conditions, the existing two-stage pressure regulating oil pump has the risk of premature displacement, resulting in excessively long oil pressure build-up time. Furthermore, when the solenoid valve fails, the displacement mechanism does not have a safety protection function and remains in low-pressure displacement mode, posing a risk to the normal operation of the engine. Utility Model Content

[0005] To address the technical problems existing in the background art, this utility model proposes a two-stage variable displacement oil pump variable displacement mechanism.

[0006] This utility model proposes a two-stage variable displacement oil pump displacement mechanism, which is installed on the oil pump. The oil pump has a control slider and a return spring. The displacement mechanism includes a valve body and a solenoid valve. The two ends of the valve body have a first oil port and a second oil port that are connected to the main lubrication oil passage of the engine and the feedback oil passage of the solenoid valve, respectively. The middle part of the valve body has a third oil port and a fourth oil port that are connected to the displacement pressure chamber of the oil pump and the oil pan, respectively. The third oil port is located on the side close to the first oil port.

[0007] The valve body is equipped with a combined valve core. The first end of the combined valve core extends into the first oil port to block the connection between the first oil port and the third oil port, and is subjected to the pressure of the engine's main lubrication oil passage.

[0008] The second end of the combined valve core extends into the valve body and is subjected to the pressure of the main oil passage of the solenoid valve. The oil pressure of the feedback oil passage of the solenoid valve is controlled by the solenoid valve to control the movement of the first end of the combined valve core in the valve body, so as to realize the connection and blockage between the third oil port and the first oil port.

[0009] To address the issues of pressure oscillation, long cold start pressure build-up time, and lack of safety protection when solenoid valves fail in existing two-stage pressure regulating oil pumps, this design incorporates a combined valve core within the valve body. The first end of the combined valve core resides in the first oil port, normally blocking the connection between the first and third oil ports. It is subjected to the pressure of the engine's main lubrication oil passage, while the second end is affected by the pressure of the solenoid valve's main oil passage. The solenoid valve can control the feedback oil passage pressure, thereby changing the pressure difference between the two ends of the combined valve core, causing its first end to move within the valve body.

[0010] When the valve core moves, the connection between the third oil port and the first oil port changes, thereby controlling the amount of oil entering the variable displacement pressure chamber of the oil pump, achieving precise adjustment of the oil pump displacement, stabilizing the oil pressure, avoiding problems such as pressure oscillation caused by sudden changes in oil chamber pressure in existing technologies, and ensuring the stable operation of the engine lubrication system.

[0011] As a further optimized solution of this utility model, the combined valve core includes a piston, a valve cap, a connecting rod, a valve plate, and a spring. One end of the connecting rod extends into the first oil port and is fixed to the piston. The other end of the connecting rod extends between the second and fourth oil ports and is connected to the valve cap. The valve plate and the spring are both fitted on the connecting rod. The valve plate is slidably connected to the connecting rod. The spring is fixedly connected between the piston and the valve plate. The valve plate is in close contact with the stepped surface inside the valve body.

[0012] This modular valve core design allows for more precise response to oil pressure changes during operation. The piston and valve cap are connected by a connecting rod, transmitting the pressure from the engine's main lubrication oil passage and the solenoid valve feedback oil passage to the entire valve core structure. The valve plate is tightly fitted to the stepped surface inside the valve body, serving a positioning and sealing function. This ensures good sealing between the oil ports during valve core movement, preventing oil leakage from affecting the displacement efficiency. A spring is installed between the piston and the valve plate, using its own elasticity to balance the oil pressure on the valve core under different operating conditions. This allows the valve core to move stably under different pressures, thereby precisely controlling the connection between the third oil port and the first oil port. This enables fine adjustment of the oil pump displacement, meeting the engine's oil pressure and flow requirements under different operating conditions.

[0013] Furthermore, the stepped surface inside the valve body is lower than the fourth oil port, the valve plate is located at the stepped surface, and the upper end surface of the valve plate is not higher than the lower end surface of the fourth oil port.

[0014] The positional relationship between the stepped surface inside the valve body, the fourth oil port, and the valve plate ensures the normal function of the fourth oil port. The fourth oil port is used to return any oil that accidentally leaks into the valve body to the oil pan. The step surface being lower than the fourth oil port prevents other components inside the valve body from obstructing the return of oil through the fourth oil port. The valve plate is positioned on the step surface, with its upper end not higher than the lower end of the fourth oil port. This ensures that the valve plate can effectively cooperate with the step surface to achieve a sealing function, while not hindering the flow of oil from the fourth oil port. This maintains the normal working order of the entire transmission mechanism and prevents oil accumulation inside the valve body from affecting the transmission effect or causing other malfunctions.

[0015] Furthermore, both the piston and valve cap are slidably sealed to the inner wall of the valve body, ensuring the sealing and reliability of the variable displacement mechanism. During operation, this sealing connection prevents oil leakage from the gap between the piston, valve cap, and the inner wall of the valve body, ensuring that the pressure of the engine lubrication main oil passage and the solenoid valve feedback oil passage can be accurately applied to the piston and valve cap, allowing the valve core to move accurately according to oil pressure changes. At the same time, the good sliding performance ensures that the piston and valve cap slide smoothly in the valve body, responding promptly to oil pressure changes and quickly adjusting the connection status between the third oil port and the first oil port, thereby precisely controlling the oil pump displacement and maintaining the stable operation of the engine lubrication system.

[0016] As a further optimized solution of this utility model, the cross-sectional area of ​​the piston is S1, the cross-sectional area of ​​the valve cap is S2, and S1>S2. The piston is subjected to the oil pressure F1 in the main lubrication oil passage of the engine, and the valve cap is subjected to the oil pressure F2 in the feedback oil passage of the solenoid valve.

[0017] The different cross-sectional areas of the piston and valve cap are key to achieving variable displacement function. Since S1 > S2, the piston and valve cap experience different pressures under the same oil pressure, which creates a pressure difference. When the engine operating conditions change and the oil pressure in the feedback oil passage of the solenoid valve changes F2, the pressure difference will change, thereby causing the valve core to move.

[0018] For example, in high-pressure mode, the solenoid valve is de-energized, and the feedback oil pressure F2 acts on the valve cap, forming a pressure difference with the pressure F1 acting on the piston in the engine's main lubrication oil passage. This pressure difference overcomes the spring force and causes the valve core to move downward, connecting the third oil port with the first oil port and reducing the oil pump displacement. This method of using different cross-sectional areas to generate pressure differences to control the movement of the valve core allows the variable displacement mechanism to respond more sensitively to changes in engine operating conditions, accurately adjust the oil pump displacement, and meet the engine's oil pressure and flow requirements under different operating conditions.

[0019] As a further optimization of this utility model, the connecting rod is hollow inside, which reduces the weight of the entire valve core assembly, lowers material costs, and also reduces the inertia of the valve core during movement, enabling it to respond more quickly to changes in oil pressure, improves the response speed of the variable displacement mechanism, and ensures that the oil pump can work stably and efficiently under different operating conditions.

[0020] As a further optimization of this utility model, the fourth oil port is located on the lower side of the valve body. The fourth oil port is a vent port used to return the oil that has accidentally leaked into the valve body to the oil pan, ensuring the normal working environment inside the transmission mechanism.

[0021] During the operation of the oil pump, a small amount of oil may leak into the valve body for various reasons. If this oil accumulates inside the valve body, it will affect the normal movement of the valve core, leading to abnormal displacement function. The existence of the fourth oil port allows the leaked oil to flow back to the oil pan in time, avoiding the adverse effects caused by oil accumulation. At the same time, as a vent, it can also discharge any air that may be present inside the valve body, preventing air accumulation from affecting oil pressure transmission and the accuracy of the displacement mechanism, and ensuring the stable and reliable operation of the entire displacement mechanism.

[0022] As a further optimization of this utility model, the solenoid valve is a normally open solenoid valve with reverse logic control. That is, when the power is off, the solenoid valve is normally open, and the second oil port is connected to the feedback oil passage of the solenoid valve. The oil pressure of the feedback oil passage is directly applied to the cross section S2 of the valve cap through the lower end of the inner cavity of the valve body.

[0023] When the engine requires high-pressure mode based on changes in speed and load, the engine ECU de-energizes the solenoid valve. Because the solenoid valve uses reverse logic control, the second oil port opens. Oil in the feedback oil passage enters the lower end of the valve body's inner cavity through the solenoid valve port. The combined valve core is subjected to the elastic force F1 from the upper end face S1 and the elastic force F2 from the lower end face S2. The main oil passage pressure in the first oil port is P, and the high-pressure control pressure is PH. The force balance equation is PH*(S1-S2)=F_elastic. When the main oil passage pressure P is higher than P_restraint… At time H, the force equation is no longer balanced, F1-F2>Fspring, the spring is compressed, the valve core moves downward, the third oil port and the first oil port are connected, the oil in the first oil port flows into the oil pump displacement pressure chamber through the third oil port, driving the oil pump control slider to produce corresponding action, reducing the oil pump displacement. Due to the reduced oil pump displacement, the output oil volume decreases, the oil pressure P in the main oil passage in the first oil port decreases, the spring force is rebalanced, and through feedback closed-loop regulation, the main oil passage pressure P reaches the control oil pressure PH required by the high pressure mode;

[0024] When the engine demands a low-pressure mode according to changes in rotational speed and load conditions, the engine ECU controls the solenoid valve to be powered on, and the second oil port is disconnected. The oil port of the solenoid valve is no longer connected to the lower end of the inner cavity of the valve body. The combined valve core is only subjected to the elastic force F1 of the upper end face S1 of the piston, and the high-pressure control pressure is PL. Its force balance equation is PL*S1 = F spring. When the main oil passage pressure P is lower than PL, the force equation is no longer balanced, F1 < F spring, the spring elongates, the combined valve core moves upward, and the third oil port is no longer connected to the first oil port. The control slider of the oil pump is driven by the internal spring force to increase the displacement of the oil pump. Since the displacement of the oil pump increases, the output oil volume increases, the oil pressure P of the main oil passage increases, and the spring force reaches a new balance. Through feedback closed-loop regulation, the oil pressure P of the main oil passage reaches the control oil pressure PL required by the low-pressure mode.

[0025] When the engine starts, the solenoid valve is in an anti-logic control mode. The second oil port is opened, and the engine oil in the solenoid valve feedback oil passage enters the lower end of the inner cavity of the valve body through the second oil port. Since the engine speed is relatively low and the engine oil pressure has not been established yet, the oil pump is in the high-pressure control mode with the maximum displacement, which can quickly build up the engine oil pressure in the main oil passage. And when the solenoid valve fails, it still remains in the initial open position, ensuring that the variable displacement mechanism of the oil pump is in the high-pressure mode, guaranteeing safety. At the same time, the power consumption of the solenoid valve is also relatively low, saving electrical power consumption.

[0026] The variable displacement mechanism of the two-stage variable displacement oil pump proposed by the present utility model has the following beneficial effects:

[0027] (1) By arranging a combined valve core in the valve body and combining the control of the solenoid valve on the oil pressure of the feedback oil passage, the present utility model realizes precise adjustment of the displacement of the oil pump, and further stably controls the engine oil pressure. When the engine operating conditions change, the solenoid valve adjusts the oil pressure of the feedback oil passage according to the command, causing the combined valve core to move, precisely controlling the connection or blockage between the third oil port and the first oil port, effectively avoiding pressure oscillations caused by sudden changes in oil cavity pressure, and ensuring the stable operation of the engine lubrication system.

[0028] (2) Through the anti-logic control of the normally open solenoid valve, when the engine starts, the solenoid valve is in the open state, and the oil pump is in the high-pressure control mode with the maximum displacement. This enables the engine oil to quickly build up pressure in the main oil passage, meeting the demand for engine oil pressure during cold start, effectively shortening the pressure build-up time during cold start, reducing the wear of the engine during the cold start stage, and extending the service life of the engine.

[0029] (iii) When the solenoid valve fails, it will remain in the initial open position, keeping the oil pump displacement mechanism in high pressure mode. This design ensures that the oil pump can still maintain a certain pressure and displacement when the solenoid valve fails, guaranteeing the engine's basic lubrication needs, avoiding serious damage to the engine due to insufficient oil pressure, and improving the reliability and safety of the entire system.

[0030] (iv) The combined valve core consists of a piston, valve cap, connecting rod, valve plate and spring. The piston and valve cap have different cross-sectional areas and are connected by a spring. This structural design allows the valve core to move more sensitively under different oil pressures, accurately control the connection state between the third oil port and the first oil port, thereby improving the accuracy of oil pump displacement regulation and better meeting the engine's precise requirements for oil pressure and flow under different operating conditions.

[0031] (v) The solenoid valve of this utility model adopts reverse logic control, which has low power consumption during normal operation. Through reasonable control logic, the solenoid valve maintains a specific state when it does not need to operate frequently, reducing unnecessary energy consumption. While ensuring the normal operation of the oil pump, it improves energy utilization efficiency, meets the energy-saving requirements of modern engines, and helps to reduce the overall energy consumption of the vehicle.

[0032] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of this utility model under high-voltage mode;

[0034] Figure 2 This is a schematic diagram of the structure of this utility model under low-pressure mode;

[0035] Figure 3 This is a schematic diagram of the combined valve core of this utility model;

[0036] Figure 4 This is a schematic diagram of the structure of this utility model installed on an oil pump.

[0037] Figure descriptions: 1. Valve body; 2. Solenoid valve; 3. First oil port; 4. Second oil port; 5. Third oil port; 6. Fourth oil port; 7. Piston; 8. Valve cap; 9. Connecting rod; 10. Valve plate; 11. Spring; 12. Oil pump; 13. Control slider; 14. Return spring. Detailed Implementation

[0038] The embodiments of this utility model are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0039] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] In the field of oil pump technology, traditional two-stage pressure regulating oil pumps have many problems, such as pressure oscillation, long cold start pressure build-up time, and lack of safety protection when the solenoid valve fails. This utility model's two-stage variable displacement oil pump variable displacement mechanism has been innovatively designed to address these problems. The specific implementation method is as follows:

[0041] like Figure 1 , Figure 2 and Figure 4 As shown, the shift mechanism mainly consists of a valve body 1 and a solenoid valve 2, which are installed on the oil pump 12. The oil pump 12 is also equipped with a control slider 13 and a return spring 14. The valve body 1 has a first oil port 3 and a second oil port 4 at its two ends. The first oil port 3 is connected to the main lubrication oil passage of the engine, and the second oil port 4 is connected to the feedback oil passage of the solenoid valve 2. The valve body 1 has a third oil port 5 and a fourth oil port 6 in the middle. The third oil port 5 is connected to the shift pressure chamber of the oil pump, and the fourth oil port 6 is connected to the oil pan. The third oil port 5 is close to the first oil port 3.

[0042] The valve body 1 is equipped with a combined valve core, which is a key component for realizing the variable displacement function. The first end of the combined valve core extends into the first oil port 3, which normally blocks the connection between the first oil port 3 and the third oil port 5. At the same time, this end is subjected to the pressure of the engine lubrication main oil passage. Its second end extends into the valve body 1 and is affected by the pressure of the solenoid valve main oil passage.

[0043] By controlling the oil pressure in the feedback oil passage through the solenoid valve 2, the pressure difference between the two ends of the combined valve core is changed, thereby controlling the first end to move within the valve body 1, realizing the connection and blockage between the third oil port 5 and the first oil port 3, thereby adjusting the amount of oil entering the variable displacement pressure chamber of the oil pump, and finally achieving precise control of the oil pump displacement.

[0044] like Figures 1-3 As shown, the combined valve core consists of a piston 7, a valve cap 8, a connecting rod 9, a valve plate 10, and a spring 11. One end of the connecting rod 9 extends into the first oil port 3 and is fixed to the piston 7, while the other end extends between the second oil port 4 and the fourth oil port 6 and is connected to the valve cap 8. The valve plate 10 and the spring 11 are both fitted on the connecting rod 9. The valve plate 10 is slidably connected to the connecting rod 9, and the spring 11 is fixed between the piston 7 and the valve plate 10. The valve plate 10 is in close contact with the stepped surface inside the valve body 1.

[0045] The connecting rod 9 is hollow inside. This design reduces the weight of the entire valve core assembly, lowers material costs, and reduces the inertia of the valve core during movement, thereby improving the response speed of the variable displacement mechanism.

[0046] The stepped surface inside the valve body 1 is lower than the fourth oil port 6. The valve plate 10 is located at the stepped surface, and the upper end of the valve plate 10 is not higher than the lower end of the fourth oil port 6. This positional relationship ensures that the function of the fourth oil port 6 as a vent and return oil is not affected, while ensuring that the valve plate 10 can effectively seal and prevent oil leakage from affecting the transmission effect.

[0047] Both piston 7 and valve cap 8 are slidably sealed to the inner wall of valve body 1, which not only ensures sealing and prevents oil leakage, but also ensures that piston 7 and valve cap 8 can slide smoothly in valve body 1 and respond to oil pressure changes in a timely manner.

[0048] like Figure 1 and Figure 2 As shown, the cross-sectional area of ​​piston 7 is S1, and the cross-sectional area of ​​valve cap 8 is S2, and S1 > S2. During operation, piston 7 is subjected to the oil pressure F1 in the main lubrication oil passage of the engine, and valve cap 8 is subjected to the oil pressure F2 in the feedback oil passage of solenoid valve 2. Due to the different cross-sectional areas, under the same oil pressure, piston 7 and valve cap 8 are subjected to different pressures, forming a pressure difference.

[0049] When the engine operating conditions change, the pressure difference changes accordingly when the solenoid valve 2 controls the change in oil pressure in the feedback oil passage F2. This changes the pressure difference, which overcomes the elastic force of the spring 11 and causes the valve core to move. This allows for precise control of the connection between the third oil port 5 and the first oil port 3, thus enabling fine adjustment of the oil pump displacement.

[0050] Solenoid valve 2 adopts a normally open design with reverse logic control. When the engine starts, solenoid valve 2 is in the open state. The oil in the feedback oil passage of solenoid valve enters the lower end of the inner cavity of valve body 1 through the second oil port 4. At this time, since the engine speed is low and the oil pressure has not yet been established, the oil pump is in high pressure control mode with the largest displacement, which can quickly establish the oil pressure in the main oil passage to meet the oil pressure requirements of the engine during cold start and reduce cold start wear.

[0051] like Figure 1As shown, when the engine enters the high-pressure mode according to changes in operating conditions such as speed and load, the engine ECU controls the solenoid valve 2 to cut off the power. Since the solenoid valve is controlled in an anti-logic manner, the second oil port 4 is opened, and the engine oil in the solenoid valve feedback oil passage enters the lower end of the inner cavity of the valve body 1 and acts on the cross-section S2 of the valve cap 8. At this time, the combined valve core is subjected to the elastic force F1 on the upper end face S1, the elastic force F2 on the lower end face S2, and the main oil passage pressure P in the first oil port 3. When the main oil passage pressure P is higher than the high-pressure control pressure PH, the force balance is broken, F1 - F2 > F spring, the spring is compressed, the valve core moves downward, the third oil port 5 is connected to the first oil port 3, and the engine oil in the first oil port 3 flows into the variable displacement pressure chamber of the oil pump through the third oil port 5, driving the control slider 13 of the oil pump to generate corresponding actions, reducing the oil pump displacement. As the oil pump displacement decreases, the output oil volume decreases, and the oil pressure P in the main oil passage of the first oil port 3 drops. The spring force reaches a new balance again. Through this feedback closed-loop regulation, the main oil passage pressure P reaches the control oil pressure PH required in the high-pressure mode;

[0052] As Figure 2 shown, when the engine is in the low-pressure mode, the engine ECU controls the solenoid valve 2 to be powered on, the second oil port 4 is disconnected, and the solenoid valve oil port is no longer connected to the lower end of the inner cavity of the valve body 1. At this time, the combined valve core is only subjected to the elastic force F1 on the upper end face S1 of the piston 7. When the main oil passage pressure P is lower than the low-pressure control pressure PL, F1 < F spring, the spring elongates, the combined valve core moves upward, the third oil port 5 is no longer connected to the first oil port 3, and the control slider 13 of the oil pump is driven by the elastic force of the internal return spring 14 to increase the oil pump displacement. As the oil pump displacement increases, the output oil volume increases, the main oil passage oil pressure P increases, and the spring force reaches a new balance again. After feedback closed-loop regulation, the main oil passage pressure P reaches the control oil pressure PL required in the low-pressure mode.

[0053] In the case of the failure of the solenoid valve 2, due to its normally open design with anti-logic control, it will maintain the initial open position, making the variable displacement mechanism of the oil pump in the high-pressure mode. This ensures that even if the solenoid valve fails, the oil pump can still maintain a certain pressure and displacement, guaranteeing the basic lubrication requirements of the engine, avoiding serious damage to the engine due to insufficient oil pressure, and enhancing the reliability and safety of the entire system. At the same time, this anti-logic control method keeps the solenoid valve in a specific state when it does not need to act frequently, reducing power consumption and improving energy utilization efficiency.

[0054] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent replacements or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A two-stage variable displacement oil pump displacement mechanism, comprising a valve body (1) and a solenoid valve (2), wherein the valve body (1) has a first oil port (3) and a second oil port (4) at both ends, which are connected to the main lubrication oil passage of the engine and the feedback oil passage of the solenoid valve (2), respectively; and the valve body (1) has a third oil port (5) and a fourth oil port (6) in the middle, which are connected to the displacement pressure chamber of the oil pump and the oil pan, respectively, wherein the third oil port (5) is located on the side close to the first oil port (3), characterized in that: The valve body (1) is equipped with a combined valve core. The first end of the combined valve core extends into the first oil port (3) to block the connection between the first oil port (3) and the third oil port (5), and is subjected to the pressure of the engine lubrication main oil passage. The second end of the combined valve core extends into the valve body (1) and is subjected to the pressure of the main oil passage of the solenoid valve. The oil pressure of the feedback oil passage of the solenoid valve is controlled by the solenoid valve (2) to control the first end of the combined valve core to move in the valve body (1), thereby realizing the connection and blockage between the third oil port (5) and the first oil port (3).

2. The variable displacement oil pump mechanism according to claim 1, characterized in that, The combined valve core includes a piston (7), a valve cap (8), a connecting rod (9), a valve plate (10), and a spring (11). One end of the connecting rod (9) extends into the first oil port (3) and is fixed to the piston (7). The other end of the connecting rod (9) extends between the second oil port (4) and the fourth oil port (6) and is connected to the valve cap (8). The valve plate (10) and the spring (11) are both mounted on the connecting rod (9). The spring (11) is fixedly connected between the piston (7) and the valve plate (10), and the valve plate (10) is in close contact with the stepped surface inside the valve body (1).

3. The variable displacement oil pump mechanism for a two-stage variable displacement system according to claim 2, characterized in that, The stepped surface inside the valve body (1) is lower than the fourth oil port (6), the valve plate (10) is located at the stepped surface, and the upper end of the valve plate (10) is not higher than the lower end of the fourth oil port (6).

4. The variable displacement oil pump mechanism for a two-stage variable displacement system according to claim 2, characterized in that, Both the piston (7) and the valve cap (8) are slidably sealed to the inner wall of the valve body (1).

5. The variable displacement oil pump mechanism for a two-stage variable displacement system according to claim 1, characterized in that, The cross-sectional area of ​​the piston (7) is S1, and the cross-sectional area of ​​the valve cap (8) is S2, and S1 > S2.

6. The variable displacement oil pump mechanism for a two-stage variable displacement system according to claim 2, characterized in that, The connecting rod (9) is hollow inside.

7. The variable displacement oil pump mechanism for a two-stage variable displacement system according to claim 1, characterized in that, The fourth oil port (6) is located on the lower side of the valve body (1). The fourth oil port (6) is a vent port used to return the oil that has accidentally leaked into the valve body (1) to the oil pan.

8. The variable displacement oil pump mechanism for a two-stage variable displacement system according to claim 1, characterized in that, The solenoid valve (2) is a normally open solenoid valve with reverse logic control.

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