Variable-displacement vane pump

Abstract

A variable displacement vane pump includes a pump housing and an eccentric ring. The pump housing has a pump chamber, an inlet and an outlet. The eccentric ring is pivotally connected to the pump housing by a rotating pin and is movably disposed in the pump chamber. A cavity between an inner surface of the pump chamber and an outer surface of the eccentric ring includes an inlet chamber, a variable feedback chamber and an outlet chamber sealed from each other. The inlet chamber is in communication with the inlet and the outlet chamber is in communication with the outlet. The outlet chamber includes first and second extensions on opposite sides of the rotating pin. The first and second extensions are configured such that a first torque exerted on the eccentric ring by fluid flowing into the first extension is greater than a second torque exerted on the eccentric ring by fluid flowing into the second extension. The first torque is in a direction to drive the eccentric ring to move in a direction to decrease a pump displacement. The present invention achieves a safe pressure relief function for a vane pump with less space and lower cost without affecting the variable control accuracy and volumetric efficiency of the vane pump.

Description

Technical Field

[0001] This invention relates to variable displacement vane pumps. Background Technology

[0002] A variable displacement vane pump mainly consists of a pump casing, an eccentric ring, a rotating pin, a return spring, a rotor, multiple vanes, and a safety valve. The pump casing has a pump chamber, an inlet, and an outlet. The eccentric ring is pivotally connected to the pump casing via a rotating pin and is movably disposed within the pump chamber to change the pump's displacement. A variable displacement feedback chamber is provided between the inner surface of the pump chamber and the outer surface of the eccentric ring. This chamber receives oil from the main oil passage of the variable displacement vane pump, thereby generating a force to move the eccentric ring and change the pump's displacement. The return spring is disposed between the pump casing and the eccentric ring to apply a biasing force to the eccentric ring. The rotor is disposed within the central hole of the eccentric ring and has a rotational axis offset from the central axis of the eccentric ring. One end of each vane is slidably disposed within a rotor slot, and the other end abuts against the inner surface of the eccentric ring. Each pair of adjacent vanes, the rotor, and the inner surface of the eccentric ring together define the working chamber. When the rotor rotates from the oil suction side (low pressure side) to the oil discharge side (high pressure side), multiple blades also rotate, and the volume of the working chamber changes. First, it increases in size to suction oil, and then it decreases in size to discharge oil. The rotor completes one oil suction and one oil discharge cycle in one rotation.

[0003] Traditional variable displacement vane pumps primarily use steel ball or plunger-type safety valves, which occupy a large space and have high manufacturing costs. The safety valves can relieve pressure internally or externally, resulting in some wasted power during operation. Furthermore, the eccentric rings in traditional variable displacement vane pumps use a semi-circular groove structure that engages with a rotating pin, which cannot completely constrain the eccentric ring to the pump casing in the radial direction. When the eccentric ring is heavy, under the influence of gravity and oil pressure, it will rub against the elastic seal located between the inner surface of the pump chamber and the outer surface of the eccentric ring, leading to abnormal wear at the sealing position when the pump operates at low oil pressure. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a variable displacement vane pump that achieves the safe pressure relief function of the vane pump with a small space and low cost, without affecting the variable control accuracy and volumetric efficiency of the vane pump.

[0005] Another technical problem to be solved by the present invention is to provide a variable displacement vane pump that can prevent abnormal friction between the eccentric ring and the elastic seal and avoid abnormal wear of the elastic seal.

[0006] This invention provides a variable displacement vane pump, including a pump casing and an eccentric ring. The pump casing has a pump chamber, an inlet, and an outlet. The eccentric ring is pivotally connected to the pump casing via a rotating pin and is movably disposed within the pump chamber to change the pump's displacement. A cavity is formed between the inner surface of the pump chamber and the outer surface of the eccentric ring. This cavity includes a sealed inlet chamber, a variable feedback chamber, and an outlet chamber. The inlet chamber communicates with the inlet, and the outlet chamber communicates with the outlet. The outlet chamber includes a first extension and a second extension located on both sides of the rotating pin. The first and second extensions are respectively close to the eccentric ring. The first and second extensions are configured such that a first torque exerted on the eccentric ring by the fluid flowing into the first extension is greater than a second torque exerted on the eccentric ring by the fluid flowing into the second extension. The directions of the first and second torques are opposite, and the direction of the first torque is the direction that drives the eccentric ring to move in a direction that reduces the pump's displacement.

[0007] The aforementioned variable displacement vane pump includes three sets of elastic seals. These three sets of elastic seals are disposed between the inner surface of the pump chamber and the outer surface of the eccentric ring, dividing the cavity between the inner surface of the pump chamber and the outer surface of the eccentric ring into a mutually sealed inlet chamber, a variable feedback chamber, and an outlet chamber.

[0008] In the aforementioned variable displacement vane pump, the rotating pin is fixed to the pump casing; the eccentric ring is provided with a pin hole, through which the rotating pin passes and is clearance-fitted with the pin hole.

[0009] By adopting the above technical solution, the present invention has at least the following advantages and features:

[0010] 1. This embodiment has a sealed inlet chamber, a variable feedback chamber, and an outlet chamber, which separates the outlet oil pressure of the vane pump from the inlet oil pressure and the variable feedback oil pressure. When the oil pressure flowing into the outlet is greater than a preset threshold, the first torque applied by the fluid flowing into the first extension to the eccentric ring can overcome the second torque applied by the fluid flowing into the second extension to the eccentric ring, pushing the eccentric ring to move in the direction of reducing the pump displacement, thereby reducing the pump outlet oil pressure and achieving the effect of safe pressure relief. This pressure relief method through outlet pressure feedback will not affect the variable control accuracy and volumetric efficiency of the vane pump. Moreover, since there is no need to set up structures such as steel balls and plungers, the spatial structure of the vane pump can be made more compact, and the manufacturing cost is also reduced.

[0011] 2. In this embodiment, the eccentric ring is assembled on the rotating pin with a full circular clearance fit, which can completely position the eccentric ring in the radial direction. This prevents the eccentric ring from vibrating under the action of gravity and oil pressure and causing abnormal friction with the elastic seal between the inner surface of the pump chamber and the outer surface of the eccentric ring, thus preventing abnormal wear of the elastic seal. Attached Figure Description

[0012] Figure 1A schematic diagram of the internal structure of a variable displacement vane pump according to an embodiment of the present invention is shown.

[0013] Figure 2 A cross-sectional schematic diagram of the rotating pin and its pin hole of a variable displacement vane pump according to an embodiment of the present invention is shown. Detailed Implementation

[0014] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0015] Please see Figure 1 According to an embodiment of the present invention, a variable displacement vane pump includes a pump casing 1, an eccentric ring 2, a rotating pin 3, a return spring 4, a rotor 5, and a plurality of vanes 6.

[0016] The pump casing 1 includes a pump chamber 10, an inlet 11, and an outlet 12. Three sets of elastic seals 7 are provided between the inner surface of the pump chamber 10 and the outer surface of the eccentric ring 2. These three sets of elastic seals 7 divide the cavity between the inner surface of the pump chamber 10 and the outer surface of the eccentric ring into a mutually sealed inlet cavity 101, an outlet cavity 102, and a variable feedback cavity 103. The inlet cavity 101 communicates with the inlet 11, the outlet cavity 102 communicates with the outlet 12, and the variable feedback cavity 103 communicates with the main oil passage of the engine lubrication system. Optionally, the elastic seals 7 are rubber seals. The sealing structure using elastic seals allows the eccentric ring 2 to swing normally.

[0017] The eccentric ring 2 is pivotally connected to the pump housing 1 via a rotating pin 3, and is movably disposed within the pump chamber 10 to change the pump's displacement. In this embodiment, the rotating pin 3 is fixed to the pump housing 1. The eccentric ring 2 has a pin hole 20, through which the rotating pin 3 passes and is clearance-fitted with the pin hole 20. In this embodiment, the rotating pin 3 is a cylindrical pin, and the pin hole 20 is a circular hole. The rotating pin 3 can control the eccentric ring 2 in the X-axis direction (…). Figure 1 (horizontal direction) and Y-axis direction ( Figure 1 The vertical degree of freedom is reduced to prevent the eccentric ring from vibrating under the influence of gravity and oil pressure, which would cause abnormal friction with the elastic seal between the inner surface of the pump chamber and the outer surface of the eccentric ring, resulting in abnormal wear of the elastic seal.

[0018] Please combine Figure 2 As shown. In this embodiment, the end face of the eccentric ring 2 is provided with a first groove 23 that penetrates the wall of the outlet cavity 102 and the pin hole 20, and the wall of the pin hole 20 is provided with a second groove 204 that penetrates along the axial direction, and the second groove 204 connects to the first groove 23. In this way, the oil in the outlet cavity 102 can flow into the second groove 204, which lubricates the outer peripheral surface of the rotating pin 3 and the wall of the pin hole 20, thereby reducing wear.

[0019] The variable feedback chamber 103 receives oil from the main oil passage of the engine lubrication system, thereby generating a force to move the eccentric ring 2 to change the pump's displacement. A return spring 4 is disposed between the pump housing 1 and the eccentric ring 2 to apply a biasing force to the eccentric ring 2. The rotor 5 is disposed within the central hole 21 of the eccentric ring 2, and the rotor 5 has a rotational axis offset from the central axis of the eccentric ring 2. One end of each blade 6 is slidably disposed within a rotor slot, and the other end abuts against the inner surface of the eccentric ring 2. In this embodiment, the outlet chamber 102 includes a first extension 105 and a second extension 106 located on both sides of the rotating pin 3. The first extension 105 and the second extension 106 are respectively close to the eccentric ring 2. The first extension 105 and the second extension 106 are configured such that the first torque exerted on the eccentric ring 2 by the fluid flowing into the first extension 105 (the fluid in this embodiment is engine oil) is greater than the second torque exerted on the eccentric ring 2 by the fluid flowing into the second extension 106. The directions of the first torque and the second torque are opposite, and the direction of the first torque is the direction that drives the eccentric ring 2 to move in a direction that reduces the pump displacement. When the variable displacement vane pump, which is an oil pump, starts, when the oil pressure flowing into the outlet 12 is greater than a preset threshold, the first torque overcomes the resistance of the second torque and pushes the eccentric ring 2 to move in a direction that reduces the pump displacement. Figure 1 The eccentric ring 2 in the middle will overcome the elastic force of the return spring 4 and rotate counterclockwise around the rotating pin 3, thereby reducing the outlet oil pressure of the vane pump and achieving the effect of safe pressure relief.

[0020] In one specific embodiment, in order to make the first torque exerted on the eccentric ring 2 by the fluid flowing into the first extension 105 greater than the second torque exerted on the eccentric ring 2 by the fluid flowing into the second extension 106, the length of the first extension 105 extending along the circumferential direction of the eccentric ring 2 is set to be greater than the length of the second extension 106 extending along the circumferential direction of the eccentric ring 2.

[0021] In this embodiment, the end face of the eccentric ring 2 is provided with a fluid output groove 25 near the outlet cavity 102, which penetrates the wall of the outlet cavity 102 and the central hole 21 of the eccentric ring 2. The pressurized fluid flows to the outlet 12 through the fluid output groove 25. This structure improves the oil output efficiency of the vane pump and solves the problems of small axial installation space and difficult layout.

[0022] In this embodiment, a fluid output groove 25 is provided on both sides of the rotating pin 3. The two fluid output grooves 25 face the first extension 105 and the second extension 106 respectively. In other embodiments, a fluid output groove 25 may be provided only on one side of the rotating pin 3.

[0023] This embodiment separates the outlet oil pressure, inlet oil pressure, and variable feedback oil pressure of the vane pump, achieving the function of safety valve integration without affecting the variable control accuracy and volumetric efficiency of the oil pump.

[0024] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A variable-displacement vane pump comprising a pump housing having a pump chamber, an inlet and an outlet, and an eccentric ring which is pivotally connected to the pump housing by a pivot pin and is movably disposed within the pump chamber to vary the displacement of the pump; a cavity being formed between the inner surface of the pump chamber and the outer surface of the eccentric ring; characterized in that, The cavity comprises an inlet cavity, a variable feedback cavity and an outlet cavity sealed from each other, the inlet cavity is in communication with the inlet, and the outlet cavity is in communication with the outlet. The outlet cavity comprises a first extension and a second extension located on two sides of the rotating pin respectively, the first extension and the second extension abut against the eccentric ring respectively, the first extension and the second extension are configured to make a first torque exerted on the eccentric ring by fluid flowing into the first extension greater than a second torque exerted on the eccentric ring by fluid flowing into the second extension, the first torque and the second torque are in opposite directions, and the direction of the first torque is a direction of driving the eccentric ring to move in a direction of reducing the displacement of the pump.

2. A variable-displacement vane pump according to claim 1, characterized in that, The variable displacement vane pump comprises three groups of elastic sealing members arranged between the inner surface of the pump chamber and the outer surface of the eccentric ring, and separating the cavity between the inner surface of the pump chamber and the outer surface of the eccentric ring into the inlet cavity, the variable feedback cavity and the outlet cavity sealed from each other.

3. A variable-displacement vane pump according to claim 2, characterized in that, The elastic sealing members are rubber sealing members.

4. A variable-displacement vane pump according to any one of claims 1 to 3, characterized in that, The rotating pin is fixed to the pump shell. The eccentric ring is provided with a pin hole, and the rotating pin passes through the pin hole and is in clearance fit with the pin hole.

5. A variable-displacement vane pump according to claim 4, characterized in that, The rotating pin is a cylindrical pin, and the pin hole is a circular hole.

6. A variable-displacement vane pump according to claim 4, characterized in that, An end surface of the eccentric ring is provided with a first groove penetrating the outlet cavity and the hole wall of the pin hole, and the hole wall of the pin hole is provided with a second groove penetrating in the axial direction, and the second groove communicates with the first groove.

7. A variable-displacement vane pump according to claim 1, characterized by An end surface of the eccentric ring is provided with a fluid output groove penetrating the outlet cavity and the hole wall of the central hole of the eccentric ring at a position close to the outlet cavity.

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