Variable-flow medium-high pressure oil pump
By introducing a pilot valve chamber and valve core structure into the gear oil pump, dynamic control of oil volume and oil pressure is achieved, solving the problems of noise and easy damage of the gear oil pump, reducing operating costs and improving energy efficiency.
Patent Information
- Application Number
- CN202422760788.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2034-11-13
AI Technical Summary
The existing gear-type oil pump has the problem that the oil pressure regulating structure produces working noise and is easily damaged, resulting in high cost of use.
A variable flow medium- and high-pressure oil pump was designed. It adopted a pilot valve cavity and valve core structure. Through the combination of diverter oil passage and return oil passage, it realized dynamic control of oil volume and oil pressure, avoided the use of pressure relief valve, and provided continuous valve core thrust through compression spring to ensure structural stability.
Effectively controls the oil pump output pressure and flow, reduces noise, extends the pump's service life, reduces maintenance costs, and improves energy efficiency.
Smart Images
Figure CN223387523U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of power equipment, in particular to a variable flow medium and high pressure oil pump. Background Art
[0002] Gear pumps are the simplest and most commonly used hydraulic pump types. Based on their structure, they can be roughly categorized into internal and external gear types, with external gear pumps being the most widely used. For example, a gear pump used to deliver oil in a vehicle's lubrication and drive systems consists of a pump housing, a pump cover secured to the housing, and two meshing gears that form a volumetric chamber. These two gears divide the enclosed space between the pump housing and the cover into an oil suction chamber and an oil discharge chamber.
[0003] When the engine's crankshaft drives the gears to mesh and rotate, the oil in the oil pan can be sucked into the oil suction chamber of the oil pump. When the two gears mesh and rotate, the oil in the oil suction chamber and the gaps between the teeth connected to it can be pressurized and squeezed out into the oil discharge chamber. Therefore, as the two gears continue to rotate and mesh at a fixed speed, the oil discharge chamber can continuously discharge a fixed flow of oil, so that mechanical parts such as the camshaft, crankshaft, connecting rod, piston, main bearing, etc. can be lubricated and operate smoothly.
[0004] In addition, a pressure relief valve is usually installed between the oil pump outlet and the main oil gallery. When the gear oil pump outlet pressure is too high, the pressure relief valve can direct excess oil discharged from the gear oil pump outlet back to the oil pan or the gear oil pump. However, since the discharge flow rate of the gear oil pump outlet is fixed, the pressure relief valve has a relatively slow pressure relief rate. As a result, under long-term high oil discharge resistance conditions, the engine crankshaft consumes relatively more driving power to maintain the fixed speed of the gear oil pump gears. Moreover, the pressure relief valve must remain open for a long time, resulting in a shorter lifespan.
[0005] In summary, the existing gear-type oil pump has technical problems such as the oil pressure regulating structure causing working noise and being easily damaged, which results in high cost of using the oil pump. Utility Model Content
[0006] The technical problem to be solved by the utility model is that the existing gear type oil pump has an oil pressure regulating structure which causes working noise and is easy to be damaged, resulting in high cost of using the oil pump.
[0007] The variable flow medium and high pressure oil pump provided by the utility model includes a pump housing and a pump cover that are interlocked, a pump chamber is provided between the pump housing and the pump cover, the pump chamber accommodates a power rotor assembly for oil pressure, an oil inlet and an oil outlet connected to the pump chamber are provided on the pump housing, a pilot valve chamber connected to the pump chamber is provided in the pump housing, a valve core that can be fed along its axial direction is provided in the pilot valve chamber, the pilot valve chamber is connected to a position near the oil outlet of the pump chamber through a bypass oil channel connected to its side, and the opening and closing of the bypass oil channel is controlled by the feeding of the valve core to change the oil flow through the oil outlet.
[0008] This variable-flow medium- and high-pressure oil pump design incorporates a pilot control design based on a general pump structure. A pilot valve chamber housing houses a valve core within the pump housing. The pilot valve chamber communicates with the pump chamber near the oil outlet, achieving oil communication and oil flow output through the pump's oil outlet via a separation oil passage. When the oil output through the pump's oil outlet reaches a pressure threshold, the oil pressure pushes the pilot valve core forward, thereby opening a bypass oil passage to divert the oil output from the outlet through the pilot valve chamber, thereby effectively controlling the pump's oil output. The opening of the bypass oil passage can preferably be controlled by the oil pressure at the pump outlet. This design effectively controls the pump's output oil pressure and flow, avoiding excessive output flow at constant speeds, such as when excessive oil flow is not required. It also avoids the need for a pressure relief valve in the pump's main oil passage, which is susceptible to damage during use. This effectively addresses the technical issue of existing gear-type oil pumps, where the oil pressure regulating structure is susceptible to damage, resulting in high pump operating costs.
[0009] As a preferred solution, the pump cover is provided with an oil return hole and an oil return passage. The oil return passage connects to the side of the pilot valve chamber through the oil return hole. The other end of the oil return passage connects to the pump chamber near the oil inlet, discharging high-pressure oil back to the pump's oil inlet. This design further optimizes the design that discharges excess oil through the pilot valve. The oil return passage is connected to the pilot valve chamber, and the excess oil diverted to the pilot valve chamber through the diverter passage is returned to the oil inlet through this return passage, allowing the oil to flow back to the pump's oil inlet and re-enter the pump unit.
[0010] As a preferred solution, a narrow mouth structure is provided in the pilot valve cavity, and the narrow mouth structure is located between the pilot valve cavity and the connecting position of the oil return hole and the diversion oil channel. The valve core is provided with a first shoulder and a second shoulder separated by a preset interval. The outer peripheral edge of the first shoulder is used to cooperate with the inner edge of the narrow mouth structure to close the pilot valve cavity on both sides of the narrow mouth structure; the second shoulder is located at the end of the valve core, and the outer peripheral shape of the second shoulder cooperates with the inner edge surface of the pilot valve cavity to seal the end of the pilot valve cavity.
[0011] This design provides a simple and effective pilot valve control design. The pilot valve cavity is axially divided into two parts by a narrow mouth structure. The communication positions with the oil return hole and the diverter oil channel are respectively located on both sides of the narrow mouth structure. The first shaft shoulder is approximately in the middle position of the valve core, and the second shaft shoulder is located near the end of the valve core. When the valve core is in the normal position, the first shaft shoulder is located at the narrow mouth structure position. The concave and convex cooperation of the two closes the two sides of the pilot valve cavity. At this time, the engine oil cannot enter the oil return channel through the pilot valve. When the oil pressure reaches the threshold, the valve core is pushed axially to push the first shaft shoulder to move, and the cooperation between the first shaft shoulder and the narrow mouth structure is released, so that the oil can return through the pilot valve cavity.
[0012] As a preferred solution, the valve core is connected to a compression spring at one end adjacent to the first shoulder, providing thrust for the valve core. This compression spring, in the absence of external force, pushes the valve core to the position where the first shoulder closes the narrow opening. This design provides automatic return power to the valve core, with the compression spring providing a continuous thrust that keeps the first shoulder of the valve core sealed against the narrow opening. The compression spring, located at the end of the valve core, uses a spring as a continuous driving force, resulting in a stable, durable, and resistant design that effectively ensures the pump's durability.
[0013] As a preferred solution, the power rotor assembly includes a driving gear and a driven gear arranged side by side, meshing with each other. The driving gear is connected to the drive mechanism via its central axis. The driving gear meshes with the driven gear, and the pressure oil is output through the continuous change of the tooth gap between the two gears. This design optimizes the structure of the power rotor assembly and adopts the basic structure of a gear pump. The pressure oil assembly mainly consists of two meshing gears. This design is simple in structure, stable in operation, and has good implementation effects.
[0014] As a preferred solution, a floating pressure plate is provided in the pump chamber, and the floating pressure plate is located between the power rotor assembly and the pump cover. The return oil channel is distributed on the periphery of the floating pressure plate on the pump cover and is laterally closed by the pump casing. The floating pressure plate is provided with a groove structure on the side adjacent to the oil inlet of the valve chamber, and the return oil channel and the oil inlet position of the pump chamber are connected through the groove structure.
[0015] This design further optimizes the overall design of the pump. A floating pressure plate structure is set in the pump cavity. The plate is located between the two gears and the pump cover. The floating pressure plate structure is filled in the pump cavity, which improves the sealing performance inside the pump. The side end face of the gear can form a tight fit with the floating pressure plate, replacing the direct fit between the gear and the high-hardness pump cover. At the same time, part of the oil circuit is set on one side of the floating pressure plate, and the return oil channel and the oil inlet part of the pump cavity are connected through the groove structure on it.
[0016] As a preferred solution, the floating pressure plate is equipped with an elastic sealing strip structure between its side end surface and the pump cover. This elastic sealing strip structure is located between the oil inlet and oil outlet of the pump chamber. The side end surface of the floating pressure plate is provided with a mounting groove for retaining the elastic sealing strip structure. This design optimizes the matching structure between the floating pressure plate and the pump cover. The elastic sealing strip elastically supports the floating pressure plate between the two, allowing it to fit tightly and elastically against the gear side end surface, further improving the sealing performance within the pump and enhancing the pump's oil pressure output efficiency.
[0017] As a preferred solution, the floating pressure plate is equipped with a surface groove structure on its end surface adjacent to the oil inlet and outlet to assist in oil storage within the pump chamber. This surface groove structure includes a transverse groove structure that connects to the central axis of the power rotor assembly for lubrication. This design optimizes the surface groove structure of the floating pressure plate, which facilitates oil flow. Specifically, the transverse groove structure connects the central axis of the pump to the oil circuit, enabling self-lubrication of the pump assembly. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a schematic diagram of the overall external structure of a variable flow medium and high pressure oil pump provided by the utility model;
[0019] Figure 2 for Figure 1 Cross-sectional diagram of a medium-variable flow medium- and high-pressure oil pump;
[0020] Figure 3 for Figure 1 A cross-sectional diagram showing the height of the pilot valve of a medium- and high-pressure oil pump with a medium-variable flow rate;
[0021] Figure 4 for Figure 1 A side cross-sectional diagram showing the location of the diverter oil passage of the medium- and high-pressure oil pump with a medium-variable flow rate;
[0022] Figure 5 for Figure 1 A side cross-sectional diagram showing the location of the oil return hole of the medium- and high-pressure oil pump with a medium-variable flow rate;
[0023] Figure 6 for Figure 1 Schematic diagram of the structure of the medium-variable flow medium- and high-pressure oil pump with the pump casing removed;
[0024] Figure 7 for Figure 6 Schematic diagram of the structure of the medium-variable flow medium- and high-pressure oil pump after removing the power rotor assembly;
[0025] Figure 8 for Figure 1 Schematic diagram of the side structure of the floating pressure plate of the medium-variable flow medium- and high-pressure oil pump;
[0026] in, Figures 1-8 middle:
[0027] 1. Pump cover; 2. Pump casing; 2-1. Pump chamber; 3. Oil outlet; 4. Oil inlet; 5. Pilot valve chamber; 5-1. Narrow mouth structure; 6. Driving gear; 7. Passive gear; 8. Floating pressure plate; 8-1. Horizontal groove structure; 8-2. Groove structure; 8-3. Elastic sealing strip structure; 9. Oil return channel; 10. Center shaft; 11. Valve core; 11-1. First shaft shoulder; 11-2. Second shaft shoulder; 11-3. Compression spring; 12. Diverter oil channel; 13. Oil return hole. DETAILED DESCRIPTION
[0028] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.
[0029] Before explaining the working principle of the present invention in detail, the description of the present invention needs to be further explained: In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "two ends," "one end," "the other end," and the like, indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0030] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc. should be understood in a broad sense. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical connection, a direct connection, an indirect connection via an intermediate medium, or a connection between two components by welding. Those skilled in the art will be able to understand the specific meanings of the above terms in this utility model in specific circumstances.
[0031] refer to Figures 1-8 The following examples are described, Figure 1 This is a schematic diagram of the overall external structure of a variable flow medium and high pressure oil pump provided by the utility model; Figure 2 for Figure 1 Cross-sectional diagram of a medium-variable flow medium- and high-pressure oil pump; Figure 3 for Figure 1 A cross-sectional diagram showing the height of the pilot valve of a medium- and high-pressure oil pump with a medium-variable flow rate; Figure 4 for Figure 1A side cross-sectional diagram showing the location of the diverter oil passage of the medium- and high-pressure oil pump with a medium-variable flow rate; Figure 5 for Figure 1 A side cross-sectional diagram showing the location of the oil return hole of the medium- and high-pressure oil pump with a medium-variable flow rate; Figure 6 for Figure 1 Schematic diagram of the structure of the medium-variable flow medium- and high-pressure oil pump with the pump casing removed; Figure 7 for Figure 6 Schematic diagram of the structure of the medium-variable flow medium- and high-pressure oil pump after removing the power rotor assembly; Figure 8 for Figure 1 Schematic diagram of the side structure of the floating pressure plate of the medium-variable flow medium- and high-pressure oil pump.
[0032] A variable flow medium and high pressure oil pump provided in this embodiment includes a pump housing 2 and a pump cover 1 that are interlocked, a pump chamber 2-1 is provided between the pump housing 2 and the pump cover 1, the pump chamber 2-1 accommodates a power rotor assembly for oil pressure, an oil inlet 4 and an oil outlet 3 connected to the pump chamber 2-1 are provided on the pump housing 2, a pilot valve chamber 5 connected to the pump chamber 2-1 is provided in the pump housing 2, a valve core 11 that can be fed along its axial direction is provided in the pilot valve chamber 5, the pilot valve chamber 5 is connected to a position near the oil outlet 3 of the pump chamber 2-1 through a bypass oil channel 12 connected to its side, and the opening and closing of the bypass oil channel 12 is controlled by the feed of the valve core 11 to change the oil flow through the oil outlet 3.
[0033] This variable flow medium and high pressure oil pump is designed with a pilot control design on the basis of a general pump basic structure. A pilot valve chamber 5 is provided in the pump housing 2 and a valve core 11 is installed in the pilot valve chamber 5. The pilot valve chamber 5 is connected to the oil outlet 3 position of the pump chamber 2-1 of the pump, and the oil circuit is connected through the separation oil channel to realize the oil flow output through the oil outlet 3 position of the pump. When the oil output through the oil outlet 3 position of the pump reaches the pressure threshold, the oil pressure pushes the valve core 11 of the pilot valve to feed, thereby opening the diversion oil channel 12 to realize the diversion and output of the oil output from the oil outlet 3 through the pilot valve chamber 5, thereby realizing effective control of the oil output of the pump, and preferably can be output through the pump outlet The oil pressure controls the opening of the bypass oil passage 12. This design effectively controls the output oil pressure and flow of the oil pump, avoiding excessive output flow at low speeds and other times when too much oil is not needed. It also effectively avoids installing a pressure relief valve in the main oil passage of the pump, which is susceptible to damage during use. In addition, in the prior art, the excess oil output by the pressure relief valve returns to the oil tank, which wastes pump power to a certain extent. However, with the design of this application, the excess oil returns to the pump's suction chamber, significantly saving power and reducing cavitation after long-term use. This effectively solves the technical problem of the existing gear-type oil pump having a high cost due to the oil pressure regulating structure being easily damaged.
[0034] In the technical solution provided by this embodiment, an oil return hole 13 and an oil return passage 9 are provided within the pump cover 1. The oil return passage 9 is connected to the side of the pilot valve chamber 5 through the oil return hole 13. The other end of the oil return passage 9 is connected to the pump chamber 2-1 near the oil inlet 4, and is used to discharge high-pressure oil back to the pump's oil inlet. This design further optimizes the design of discharging excess oil through the pilot valve design. The oil return passage 9 is connected to the pilot valve chamber 5. The excess oil diverted to the pilot valve chamber 5 through the diverter passage 12 is returned to the oil inlet through the oil return passage 9, which can return the engine oil to the pump's oil inlet and re-enter the pump device.
[0035] In the technical solution provided in this embodiment, a narrow mouth structure 5-1 is provided in the pilot valve chamber 5, and the narrow mouth structure 5-1 is located between the communication position of the pilot valve chamber 5 and the return oil hole 13 and the diversion oil channel 12. The valve core 11 is provided with a first shaft shoulder 11-1 and a second shaft shoulder 11-2 separated by a preset interval. The outer peripheral edge of the first shaft shoulder 11-1 is used to match the inner edge of the narrow mouth structure 5-1 in a concave and convex manner to close the pilot valve chamber 5 on both sides of the narrow mouth structure 5-1; the second shaft shoulder 11-2 is located at the end of the valve core 11, and the outer peripheral shape of the second shaft shoulder 11-2 matches the inner edge surface of the pilot valve chamber 5 to seal the end of the pilot valve chamber 5.
[0036] This design provides a simple and effective pilot valve control design. The pilot valve chamber 5 is axially divided into two parts by the narrow mouth structure 5-1. The communication positions with the return oil hole 13 and the diverter oil channel 12 are respectively located on both sides of the narrow mouth structure 5-1. The first shaft shoulder 11-1 is approximately in the middle position of the valve core 11, and the second shaft shoulder 11-2 is located near the end of the valve core 11. When the valve core 11 is in the normal position, the first shaft shoulder 11-1 is located at the position of the narrow mouth structure 5-1. The concave and convex fit of the two closes the two sides of the pilot valve chamber 5. At this time, the engine oil cannot enter the return oil channel 9 through the pilot valve. When the oil pressure reaches the threshold, the valve core 11 is pushed axially to push the first shaft shoulder 11-1 to move. The fit between the first shaft shoulder 11-1 and the narrow mouth structure 5-1 is released, and the oil can flow back through the pilot valve chamber 5.
[0037] In the technical solution provided in this embodiment, a compression spring 11-3 is connected to the end of the valve core 11 adjacent to the first shoulder 11-1, which is used to provide thrust for the valve core 11. This compression spring 11-3, in the absence of external force, pushes the valve core 11 to a position where the first shoulder 11-1 closes the narrow opening structure 5-1. This design provides an automatic return force for the valve core 11. The continuous thrust provided by the compression spring 11-3 maintains the position where the first shoulder 11-1 of the valve core 11 is sealed against the narrow opening structure 5-1. The location of the compression spring 11-3 at the end of the valve core 11 and the use of a spring as a continuous driving force make the design stable, durable, and resistant to damage, effectively ensuring the durability of the pump.
[0038] In the technical solution provided by this embodiment, the power rotor assembly includes a driving gear 6 and a driven gear 7 arranged side by side and meshing with each other. The driving gear 6 is connected to the drive mechanism via its central shaft 10. The meshing of the driving gear 6 drives the driven gear 7, and the pressure oil output is achieved through the continuous change in the gap between the two gears. This design optimizes the structure of the power rotor assembly, adopting the basic structure of a gear pump. The pressure oil assembly mainly consists of two meshing gears. This design is simple in structure, stable in operation, and has good implementation effects.
[0039] In the technical solution provided in this embodiment, a floating pressure plate 8 is provided in the pump chamber 2-1, and the floating pressure plate 8 is located between the power rotor assembly and the pump cover 1. The return oil channel 9 is distributed on the periphery of the floating pressure plate 8 on the pump cover 1 and is laterally closed by the pump housing 2. The floating pressure plate 8 is provided with a groove structure 8-2 on the side adjacent to the oil inlet 4 of the valve chamber, and the return oil channel 9 and the oil inlet 4 position of the pump chamber 2-1 are connected through the groove structure 8-2.
[0040] This design further optimizes the overall design of the pump. A floating pressure plate 8 is provided in the pump chamber 2-1. The plate is located between the two gears and the pump cover 1. The floating pressure plate 8 is filled in the pump chamber 2-1, thereby improving the sealing performance inside the pump. The side end face of the gear can form a tight fit with the floating pressure plate 8, replacing the direct fit between the gear and the high-hardness pump cover 1. At the same time, part of the oil circuit is provided on one side of the floating pressure plate 8, and is connected to the return oil channel 9 and the oil inlet part of the pump chamber 2-1 through the groove structure 8-2 thereon.
[0041] In the technical solution provided by this embodiment, a resilient sealing strip structure 8-3 is provided between the side end surface of the floating pressure plate 8 and the pump cover 1. This resilient sealing strip structure 8-3 is positioned between the oil inlet 4 and the oil outlet 3 of the pump chamber 2-1. The side end surface of the floating pressure plate 8 is provided with a mounting groove for retaining the resilient sealing strip structure 8-3. This design optimizes the fit between the floating pressure plate 8 and the pump cover 1. The resilient support provided by the resilient sealing strip allows the floating pressure plate 8 to be securely attached to the gear side surface with a certain degree of elasticity, further enhancing the pump's internal sealing performance and improving the pump's oil pressure output efficiency.
[0042] In the technical solution provided by this embodiment, the floating pressure plate 8 is provided with a surface groove structure on its end surface adjacent to the oil inlet 4 and oil outlet 3 to assist in oil storage within the pump chamber 2-1. This surface groove structure includes a transverse groove structure 8-1 that connects to the central shaft 10 of the power rotor assembly, thereby providing lubrication for the power rotor assembly. This design optimizes the surface groove structure of the floating pressure plate 8, which facilitates oil flow. Specifically, the transverse groove structure 8-1 connects the central shaft 10 of the pump to the oil circuit, enabling self-lubrication of the pump assembly.
[0043] Although the disclosure is as described above, the scope of protection of the disclosure is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the scope of protection of the utility model.
Claims
1. A variable flow medium and high pressure oil pump, comprising a pump housing (2) and a pump cover (1) that are engaged with each other, a pump cavity (2-1) being provided between the pump housing (2) and the pump cover (1), a power rotor assembly for pressurizing oil being accommodated in the pump cavity (2-1), an oil inlet (4) and an oil outlet (3) being provided on the pump housing (2) and communicating with the pump cavity (2-1), characterized in that: A pilot valve chamber (5) communicating with the pump chamber (2-1) is provided in the pump housing (2). A valve core (11) capable of feeding along its axis is provided in the pilot valve chamber (5). The pilot valve chamber (5) is connected to a position near the oil outlet (3) of the pump chamber (2-1) via a bypass oil passage (12) connected to its side. The opening and closing of the bypass oil passage (12) is controlled by the feeding of the valve core (11) to change the oil flow through the oil outlet (3).
2. The variable flow medium and high pressure oil pump according to claim 1, characterized in that: An oil return hole (13) and an oil return passage (9) are provided in the pump cover (1). The oil return passage (9) is connected to the side of the pilot valve chamber (5) through the oil return hole (13). The other end of the oil return passage (9) is connected to the pump chamber (2-1) near the oil inlet (4) for discharging high-pressure oil back to the oil inlet of the pump.
3. The variable flow medium and high pressure oil pump according to claim 2, characterized in that: A narrow mouth structure (5-1) is provided in the pilot valve cavity (5), and the narrow mouth structure (5-1) is located between the pilot valve cavity (5) and the communication position of the oil return hole (13) and the diversion oil channel (12); the valve core (11) is provided with a first shaft shoulder (11-1) and a second shaft shoulder (11-2) separated by a preset interval; the outer peripheral edge of the first shaft shoulder (11-1) is used to match the inner side edge of the narrow mouth structure (5-1) in a concave-convex manner to close the pilot valve cavity (5) on both sides of the narrow mouth structure (5-1); the second shaft shoulder (11-2) is located at the end of the valve core (11), and the outer peripheral shape of the second shaft shoulder (11-2) matches the inner edge surface of the pilot valve cavity (5) to block the end of the pilot valve cavity (5).
4. The variable flow medium and high pressure oil pump according to claim 3, characterized in that: The valve core (11) is connected to a compression spring (11-3) at one end adjacent to the first shaft shoulder (11-1) for providing thrust to the valve core (11). The compression spring (11-3) pushes the valve core (11) to a position where the first shaft shoulder (11-1) closes the narrow mouth structure (5-1) without external force.
5. The variable flow medium and high pressure oil pump according to any one of claims 2 to 4, characterized in that: The power rotor assembly comprises a driving gear (6) and a driven gear (7) arranged side by side and meshing with each other. The driving gear (6) is connected to the driving mechanism through its central shaft (10). The driven gear (7) is driven by the meshing of the driving gear (6), and oil pressure is outputted through the continuous change of the tooth gap between the two gears.
6. The variable flow medium and high pressure oil pump according to claim 5, characterized in that: A floating pressure plate (8) is provided in the pump chamber (2-1), and the floating pressure plate (8) is located between the power rotor assembly and the pump cover (1). The return oil passage (9) is distributed on the periphery of the floating pressure plate (8) on the pump cover (1) and is laterally closed by the pump housing (2). The floating pressure plate (8) is provided with a groove structure (8-2) on a side adjacent to the oil inlet (4) of the valve chamber, and the return oil passage (9) and the oil inlet (4) of the pump chamber (2-1) are connected through the groove structure (8-2).
7. The variable flow medium and high pressure oil pump according to claim 6, characterized in that: The floating pressure plate (8) is provided with an elastic sealing strip structure (8-3) between its side end surface and the pump cover (1); the elastic sealing strip structure (8-3) is located between the oil inlet (4) and the oil outlet (3) of the pump chamber (2-1); and the side end surface of the floating pressure plate (8) is provided with a mounting groove for clamping the elastic sealing strip structure (8-3).
8. The variable flow medium and high pressure oil pump according to claim 6, characterized in that: The floating pressure plate (8) is provided with a surface groove structure on the end surface adjacent to the oil inlet (4) and the oil outlet (3), for assisting the storage of oil in the pump chamber (2-1); the surface groove structure includes a transverse groove structure (8-1) connected to the central axis (10) of the power rotor assembly, for lubricating the power rotor assembly and controlling oil unloading.