Variable displacement vane pump

Abstract

The invention provides a variable displacement vane pump which can adjust the full cut-off pressure in a wide range from low pressure to high pressure by using a single pump without changing a spring. A vane pump is provided with: a plurality of vanes slidably protruding from a rotor that is rotatable about a shaft; a cam ring having an inner peripheral surface in sliding contact with the outer peripheral end of the blade, and being eccentrically rotatable with respect to the shaft; a high-pressure-side spring that urges the cam ring via the plunger; a low-pressure-side spring which is at least partially housed in the holder and which biases the cam ring via the holder and the plunger; a stopper provided on an end side of the low-pressure-side spring opposite to the plunger side; and a pressure adjusting part capable of adjusting the position of the stopper from a position where the stopper does not abut against the stopper even if the cam ring moves the holder to a position where the stopper always contacts the holder or more.

Description

Technical Field

[0001] This invention relates to a variable capacity vane pump used as a hydraulic source for working oil. Background Technology

[0002] As an example, in various machines, a variable-capacity vane pump that varies the discharge volume is used as the hydraulic source for the working oil (e.g., Patent Document 1). The variable-capacity vane pump of Patent Document 1 has a rotor, multiple vanes, and a cam ring, such that the eccentricity of the cam ring relative to the rotor varies according to the load pressure, thereby discharging the required discharge volume.

[0003] In a variable displacement vane pump, in the initial state before the cam ring moves, a retainer, subjected to forces by two springs with different spring constants (a low-pressure side spring and a high-pressure side spring), abuts against the cam ring. Therefore, a load determined by the combined spring constant of the two springs acts from the retainer through the plunger onto the cam ring. The cam ring is eccentrically fixed by this load.

[0004] Next, as the pressure inside the pump chamber rises, the cam ring moves the distance from the retainer to the plunger. The retainer then abuts against the plunger, preventing further compression of the low-pressure side spring, which then ceases to function. When the pressure inside the pump chamber rises further, a load is applied to the cam ring according to the spring constant of the high-pressure side spring. The cam ring moves against this load. Then, at the moment the pump's discharge pressure reaches an arbitrary set pressure, it enters a fully shut-off state. Furthermore, full shut-off indicates that the cam ring's movement is close to its eccentricity, the eccentricity of the cam ring is zero, and the pump's discharge flow rate is approximately zero.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 5521626 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] In the variable-capacity vane pump of Patent Document 1, the distance from the retainer to the plunger is less than or equal to the allowable eccentricity of the cam ring. Therefore, when setting the initial load via the pressure adjustment unit, the adjustment range of the low-pressure side spring is narrowed. That is, the setting range of the complete shut-off pressure is limited to a narrow range. As a result, when the complete shut-off pressure is used over a wide range from low to high pressure, it is necessary to change the spring combination for each setting range.

[0010] Furthermore, in the case of vane pumps with integrated motors, the output motor needs to vary depending on the pump's set pressure range. For example, when using a permanent magnet motor (IPM motor, etc.), if the pump is separated, the motor rotor will be attracted to the stator due to magnetic force. Therefore, it is difficult to reassemble without special equipment, and it is difficult to replace only the motor. In other words, a prescribed quantity of inventory must be prepared (managed) for each set pressure range.

[0011] In view of such a problem, the present invention aims to provide a variable capacity vane pump that can adjust the complete shut-off pressure over a wide range from low to high pressure with a single pump without changing the spring.

[0012] Solution for solving the problem

[0013] To address the aforementioned issues, the variable-capacity vane pump of the technical solution comprises: a rotor capable of rotating about an axis; a plurality of vanes that slidably protrude from the rotating rotor; and a cam ring having an inner circumferential surface for sliding contact with the outer circumferential ends of the vanes protruding from the rotor, and being eccentric relative to the axis. The variable-capacity vane pump further comprises: a plunger; a high-pressure side spring that applies force to the cam ring via the plunger; a retainer; a low-pressure side spring that is at least partially housed in the retainer and applies force to the cam ring via the retainer and the plunger; a stop member disposed at the end opposite to the plunger side of the low-pressure side spring; and a pressure adjusting unit that displaces the stop member, such that even with movement of the cam ring, the pressure adjusting unit can adjust the position of the stop member from a position where the retainer does not abut against the stop member to a position where the stop member is always in contact with the retainer.

[0014] Preferably, the pressure adjustment unit can adjust the position of the stop member to a position where the retainer never contacts the stop member and to a position where the retainer contacts the stop member midway through the eccentricity of the cam ring from its maximum to zero.

[0015] The effects of the invention

[0016] Based on the above structure, a variable capacity vane pump can be provided, which can adjust the complete shut-off pressure over a wide range from low pressure to high pressure with a single pump without changing the spring. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the variable capacity vane pump according to the embodiment.

[0018] Figure 2 yes Figure 1 XX sectional view of a vane pump.

[0019] Figure 3This diagram shows the contact state between the stop and the retainer when the vane pump is at full flow.

[0020] Figure 4 It is a chart representing the control characteristics of a vane pump.

[0021] Explanation of reference numerals in the attached figures

[0022] 100. Vane pump; 102. Electric motor; 104. Motor shaft; 106. Motor rotor; 108. Stator; 110. Motor housing; 112. Main body of vane pump; 114. Connector; 116. Rotating shaft; 118. Oil seal; 120. Rotor; 122. Vane; 124. Cam ring; 126. Vane groove; 128. Inner circumferential surface of cam ring; 130. Outer circumferential end of vane; 132. Pressure adjustment part; 134. Discharge adjustment part; 136. Adapter; 138. Pressure adjustment threaded part; 140. Outer circumferential surface of cam ring; 142. Discharge adjustment threaded part; 144. Ring position adjustment part; 146. Ring position adjustment screw. 148. Plunger; 148a. Plunger abutment surface; 148b. Plunger flange; 150. High-pressure side spring; 150a. One end of the high-pressure side spring; 150b. The other end of the high-pressure side spring; 152. Retainer; 152a. Bottom of the retainer; 152b. Flange of the retainer; 154. Low-pressure side spring; 154a. One end of the low-pressure side spring; 154b. The other end of the low-pressure side spring; 156. Stop; 156a. Stop abutment surface; 156b. Stop pressing surface; 158. Oil drain port; 160. Spring chamber; 162. Cover; 164. Inlet; 166. Outlet; 168. Pump chamber. Detailed Implementation

[0023] Hereinafter, this embodiment will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in this embodiment are merely illustrative examples for easy understanding of the invention and do not limit the invention unless specifically stated otherwise. Furthermore, in this specification and the accompanying drawings, elements with substantially the same function or structure are omitted from repeated description by using the same reference numerals, and elements not directly related to the present invention are omitted from the illustrations.

[0024] Figure 1 This is a cross-sectional view of a variable capacity vane pump (hereinafter referred to as vane pump 100) according to an embodiment. Figure 2 yes Figure 1 A cross-sectional view of a vane pump 100. The vane pump 100 is a pump that varies the discharge rate and is used as a hydraulic source for working oil in various machines. Here, a vane pump 100 is illustrated. Figure 1 The vane pump shown is an integrated motor type with motor 102.

[0025] The electric motor 102 has a motor shaft 104, a motor rotor 106, and a stator 108, which are housed in a motor housing 110. When current is applied to the electric motor 102, the motor shaft 104 rotates together with the motor rotor 106 through the interaction between the motor rotor 106 and the stator 108.

[0026] The motor shaft 104 extends within the body 112 of the vane pump 100 and is connected to the pump shaft, i.e., the rotating shaft 116 of the vane pump 100, via a connector 114. Furthermore, the gap between the motor shaft 104 and the body 112 is sealed by an oil seal 118. Additionally, as... Figure 1 As shown, the motor housing 110 of the electric motor 102 is connected to the main body 112 of the vane pump 100 in an integral manner.

[0027] like Figure 2 As shown, the vane pump 100 includes a pump rotor (hereinafter referred to as rotor 120), a plurality of vanes 122, and a cam ring 124. The rotor 120 is integrally supported with a rotating shaft 116 and is capable of rotating about the rotating shaft 116. The vanes 122 pass through a cam ring 124. Figure 2 The blade slots 126 of the rotor 120 shown protrude slidably from the rotating rotor 120.

[0028] The cam ring 124 is a cylindrical component that can be eccentric relative to the rotation axis 116. Here, the eccentricity tolerance (eccentricity) of the cam ring 124 is set as e (refer to...). Figure 2 The outer peripheral end 130 of the blade 122 protruding from the rotor 120 slides in contact with the inner peripheral surface 128 of the cam ring 124.

[0029] On one side of the cam ring 124 ( Figure 2 On the left side, there is a pressure adjusting part 132 for adjusting the discharge pressure of the vane pump 100, and on the other side ( Figure 2 On the right side) is a discharge volume adjustment section 134. On the side of the main body 112 where it meets the receiving cam ring 124 ( Figure 2 An opening is provided on the opposite side (right side) of the main body 112. The opening of the main body 112 is closed by the adapter 136. On one end face of the main body 112 located outside the opening, a hole is provided for receiving a fixing member for fixing the adapter 136 to the main body 112. In addition, in the adapter 136, a pair of through holes are provided at positions opposite to the hole on one end face of the main body 112.

[0030] The fixing component passes through the through hole, and its front end is held by the hole in the main body 112, thereby fixing the adapter 136 to the main body 112. In the adapter 136, a through hole is also provided between a pair of through holes for fixing to the main body 112. The pressure adjusting thread 138 of the pressure adjusting part 132 engages with the through hole. The pressure adjusting thread 138 passes through the through hole of the adapter 136, and its front end is displaced relative to the main body 112 by moving forward and backward. The discharge volume adjusting part 134 is provided in the main body 112 and has a discharge volume adjusting thread 142 on the outer peripheral surface 140 of the pressing cam ring 124.

[0031] Furthermore, a ring position adjustment part 144 is provided in the main body 112. Figure 2 (the upper side).

[0032] The ring position adjustment section 144 has a ring position adjustment thread 146 that presses against the outer peripheral surface 140 of the cam ring 124. The position of the cam ring 124 is adjusted by displacing the ring position adjustment thread 146 in the axial direction. Furthermore, the ring position adjustment thread 146 is approximately orthogonal to the pressure adjustment thread 138 of the pressure adjustment section 132 and the discharge flow adjustment thread 142 of the discharge flow adjustment section 134.

[0033] The vane pump 100 also includes a plunger 148, a high-pressure side spring 150, a retainer 152, a low-pressure side spring 154, and a stop 156. The plunger 148 is a component that abuts against the cam ring 124, and has a contact surface 148a and a flange portion 148b. The contact surface 148a of the plunger 148 abuts against the outer peripheral surface 140 of the cam ring 124. One end 150a of the high-pressure side spring 150 abuts against the flange portion 148b.

[0034] The retainer 152 is a bottomed hollow cylinder housing the high-pressure side spring 150. A low-pressure side spring 154 is housed inside the retainer 152. The retainer 152 has a bottom 152a and a flange 152b. One end 154a of the low-pressure side spring 154 abuts against the bottom 152a of the retainer 152. The other end 150b of the high-pressure side spring 150 abuts against the flange 152b. Thus, the retainer 152 applies force to the high-pressure side spring 150 towards the cam ring 124. Furthermore, the high-pressure side spring 150 applies force to the plunger 148 towards the cam ring 124. Alternatively, the retainer 152 may have a structure without a bottom 152a, but with a locking portion for engaging one end 154a of the low-pressure side spring 154. In this case, the retainer 152 becomes a bottomless cylindrical shape with a flange on the pressure adjustment part 132 side.

[0035] The stop member 156 has an abutment surface 156a and a pressing surface 156b. The abutment surface 156a of the stop member 156 has a recessed portion that faces the other end 154b of the low-pressure side spring 154, recessed towards the pressure adjustment portion 132. This other end 154b abuts against and is received in this recess (first recess). The pressing surface 156b is located opposite the abutment surface 156a in the stop member 156. The pressing surface 156b has a recessed portion that faces the plunger 148, abutting against or receiving the end of the pressure adjustment threaded member 138 in this recess (second recess). Depending on the movement of the pressure adjustment threaded member 138, the stop member 156 displaces the other end 154b of the low-pressure side spring 154 towards the cam ring 124. Furthermore, the low-pressure side spring 154 applies force to the retainer 152 towards the cam ring 124. Furthermore, the structure is not limited to the structure that accommodates and holds the low-pressure side spring 154 through the recess; for example, it may also be a structure that engages the spring end through a locking part (not shown).

[0036] Furthermore, the pressure adjustment part 132 is displaced in the axial direction by screwing in the pressure adjustment thread 138, thereby pressing the pressing surface 156b of the stop 156 towards the cam ring 124 side and adjusting the position of the stop 156 (displacing the stop 156). Here, let the screwing amount of the pressure adjustment thread 138 be α, and let the distance between the abutting surface 156a of the stop 156 and the flange portion 152b of the retainer 152 (hereinafter referred to as the distance between the stop 156 and the retainer 152) be St. In addition, the screwing amount α can also be said to be the length of the gap between the stop 156 and the opening side end face of the main body 112. That is, the screwing amount α is the length of the advance and retraction of the thread in the gap on the pressing surface 156b side of the stop 156. Figure 2 , Figure 3 In the example, it can also be described as the length between the pressing surface 156b and its opposite (opposite) surface (adapter 136).

[0037] exist Figure 2 In the vane pump 100 shown, the screw-in amount α of the pressure adjusting thread 138 is sufficiently small; therefore, the distance St between the stop 156 and the retainer 152 is large (St > 0), and the stop 156 does not abut against the retainer 152. However, the distance St is not only determined by the screw-in amount α, but sometimes varies depending on the pump capacity. Regarding this distance St, refer to... Figure 3 and Figure 4 To be described later.

[0038] With the stop 156 not abutting against the retainer 152, the low-pressure side spring 154 housed in the retainer 152 functions to apply force to the retainer 152 toward the cam ring 124. Therefore, the load determined by the combined spring constant of the high-pressure side spring 150 and the low-pressure side spring 154, which have different spring constants, acts from the retainer 152 onto the cam ring 124 via the plunger 148.

[0039] Here, when the spring constant of the low-pressure side spring 154 is set to K1, the spring constant of the high-pressure side spring 150 is set to K2, and the combined spring constant is set to K, the combined spring constant is determined by "1 / K = 1 / K1 + 1 / K2". That is, when the stop member 156 is not in contact with the retainer member 152, the cam ring 124 is subjected to a load determined by a spring constant less than K2 and becomes eccentric.

[0040] Furthermore, in the vane pump 100, when the tightening amount α of the pressure adjusting thread 138 is sufficiently small, as described below. That is, as... Figure 2 As shown, the distance St between the abutment surface 156a of the stop member 156 and the flange portion 152b of the retainer 152 is greater than the eccentricity allowance e of the cam ring 124 (St>e).

[0041] That is, even if the cam ring 124 moves in a manner where St > e, the pressure adjusting unit 132 can adjust the position of the stop member 156 to a position where the retaining member 152 does not abut against the stop member 156 (always at the position where St > 0). "The cam ring 124 moves in a manner where St > e" means that even in a fully closed state, the stop member 156 does not abut against the retaining member 152. Furthermore, the fully closed state means that the cam ring 124 moves with zero eccentricity, and the discharge flow rate (discharge volume) of the vane pump 100 is approximately zero. Details will be described later. In addition, the position of the stop member 156 can also be understood as the contact position between the stop member 156 and the low-pressure spring 154.

[0042] Additionally, the vane pump 100 body 112 is provided with an oil drain port 158 ​​connected to an oil drain tank (not shown) at atmospheric pressure. The oil drain port 158 ​​communicates with a spring chamber 160 that houses the high-pressure side spring 150 and the low-pressure side spring 154. The oil drain port 158 ​​draws in or discharges working oil from the outside according to the volume change of the spring chamber 160 filled with working oil.

[0043] Figure 2The vane pump 100 shown is in its full flow state (the state with the maximum pump capacity). The full flow state refers to the state where the cam ring 124 is most eccentrically abutted against the discharge adjustment thread 142 of the discharge adjustment unit 134 relative to the rotor 120 (or the rotating shaft 116). When the discharge adjustment unit 134 displaces the discharge adjustment thread 142 in the axial direction, the clearance between the rotor 120 and the cam ring 124 is adjusted. That is, the maximum eccentricity of the cam ring 124 in the full flow state is adjusted by the discharge adjustment thread 142. Thus, the adjustment is made from the position provided... Figure 1 The maximum discharge volume of working oil flowing from the suction port 164 of the shown cover 162 to the discharge port 166. In addition, the cover 162 is integrally formed with the body 112 of the vane pump 100.

[0044] The operation of the vane pump 100 is explained here. The vane pump 100... Figure 2 When rotor 120 rotates counterclockwise under the full flow condition shown, working oil flows from the suction area on the lower side of the expanded volume of pump chamber 168. Figure 1 The suction port 164 shown is drawn into the pump chamber 168. Moreover, in the vane pump 100, in the discharge area on the upper side of the pump chamber 168 where the volume is reduced, pressurized working oil is discharged from the pump chamber 168 to the discharge port 166.

[0045] The discharge rate of the working oil during operation of the vane pump 100 is determined by the eccentricity of the cam ring 124 relative to the rotor 120. When the pressure of the working oil in the discharge region of the pump chamber 168 rises, it exceeds the load acting on the cam ring 124 via the plunger 148. Furthermore, this load is determined by the combined spring constant K of the high-pressure side spring 150 and the low-pressure side spring 154. When the pressure of the working oil exceeds the load acting on the cam ring, the cam ring 124 moves in the direction of decreasing eccentricity (the direction of pushing back the plunger 148).

[0046] Furthermore, when the eccentricity of the cam ring 124 is zero, the size of the pump chamber 168 does not change even if the rotor 120 rotates. Therefore, the vane pump 100 reaches a completely shut-off state where it almost does not discharge working oil. Additionally, the pressure at which this completely shut-off state occurs is called the complete shut-off pressure.

[0047] Figure 3 This diagram shows the contact state between the stop member 156 and the retainer 152 when the vane pump 100 is at full flow. In the vane pump 100, the screwing amount α increases by screwing in the pressure adjusting thread 138 of the pressure adjusting part 132. When the screwing amount α increases, the abutment surface 156a of the stop member 156 abuts against the flange portion 152b of the retainer 152 (St=0).

[0048] Therefore, the low-pressure side spring 154 housed in the retainer 152 is no longer further compressed and does not function. When the low-pressure side spring 154 does not function, the cam ring 124 is eccentrically subjected to a load determined by the larger spring constant K2 of the high-pressure side spring 150.

[0049] Figure 4 This is a graph representing the control characteristics of the vane pump 100. In the graph, the horizontal axis represents pressure (MPa), and the vertical axis represents pump capacity (cm3 / rev). Additionally, the pressure at which the pump capacity is approximately zero (completely shut off) is called the complete shut-off pressure.

[0050] Therefore, the range shown by Pa-Pb on the horizontal axis of the chart becomes the pressure adjustment range for the complete cutoff pressure.

[0051] In the diagram, the black dot indicates the moment when the stop 156 and the retainer 152 come into contact.

[0052] α1 is the screw-in amount by which the pressure adjusting thread 138 is loosened to its maximum extent, approximately bringing the stop 156 into contact with the adapter 136. α2 is the screw-in amount by which the pressure adjusting thread 138 is screwed in, bringing the stop 156 into contact with the retainer 152 when fully stopped. α6 is the screw-in amount by which the stop 156 into contact with the retainer 152 when the flow is at full capacity. α3 to α5, between α2 and α6, are examples of the screw-in amounts by which the stop 156 into contact with the retainer 152 midway from full capacity to full stop. α7 is a further screw-in amount than α6.

[0053] R1 represents the range of set pressures (complete cut-off pressures) corresponding to the screw-in amounts α1 to α2. Figure 2 The control characteristics of the vane pump 100 are shown. Figure 2 In the vane pump 100 shown, as described above, the screw-in amount α of the pressure adjusting thread 138 is small enough that even if the cam ring 124 moves in a manner where St > e, the retaining member 152 is adjusted to a position where it does not abut against the stop member 156 (always becoming the position where St > 0). Therefore, the cam ring 124 moves with zero eccentricity, and the low-pressure side spring 154 continues to function until it reaches a fully closed state.

[0054] Therefore, the cam ring 124 is eccentrically subjected to a load determined by a smaller spring constant K, which is the resultant spring constant K of the high-pressure side spring 150 and the low-pressure side spring 154. Furthermore, as mentioned above, the resultant spring constant K is "1 / K = 1 / K1 + 1 / K2". Therefore, with the low-pressure side spring 154 continuously functioning, the vane pump 100 can set the complete shut-off pressure to a low pressure as shown in range R1. Additionally, as shown in range R1, the vane pump 100 reaches the complete shut-off state from the full flow state with a slope determined by the aforementioned resultant spring constant K.

[0055] The range R2 of set pressure corresponding to the screw-in amounts α2 to α6 represents the control characteristics of the vane pump 100 as follows: That is, the range R2 is the ratio of the screw-in amount α of the pressure adjusting thread 138 to the screw-in amount α. Figure 2 The shown vane pump 100 has a large screw-in capacity and is larger than... Figure 3 When the screw-in amount of the vane pump 100 shown is small.

[0056] In this case, the pressure adjustment unit 132 keeps the position of the stop member 156 within the allowable eccentricity e of the cam ring 124 (St < e). That is, the pressure adjustment unit 132 can be adjusted to a position where the stop member 156 contacts the retainer 152 midway through the movement of the cam ring 124 to reach a fully stopped state (St = 0).

[0057] As a result, the cam ring 124 is eccentrically loaded with a small spring constant until the stop 156 no longer abuts against the retainer 152 (St > 0). This small spring constant load is determined by the combined spring constant K of the high-pressure side spring 150 and the low-pressure side spring 154. Then, when the stop 156 contacts the retainer 152 (St = 0), the low-pressure side spring 154 is no longer compressed and ceases to function.

[0058] When the low-pressure side spring 154 is in a non-functional state, the cam ring 124 is eccentrically subjected to a load determined by the large spring constant K2 of the high-pressure side spring 150. Therefore, in the middle of the process of reaching the fully shut-off state, when the low-pressure side spring 154 is in a non-functional state, the vane pump 100 can set the fully shut-off pressure to high pressure compared to range R1, as shown in range R2.

[0059] Furthermore, the slope from the full flow state to the black point is the same as the slope of the control characteristic corresponding to α1, and the slope from the black point to the complete cutoff state is the same as the slope of the control characteristic corresponding to α6.

[0060] Here, Figure 3 The vane pump 100 shown is equivalent to a screw-in amount α6, and is adjusted to the position where the stop 156 contacts the retainer 152 (St=0). However, the pressure adjustment unit 132 can also adjust the position of the stop 156 to a position where the stop 156 is always in contact with the retainer 152 (St=0) "or higher" (i.e., closer to the position of the cam ring 124 than the position where the stop 156 contacts the retainer 152).

[0061] The range R3 of the set pressure corresponding to the screw-in amount α6 to α7 represents the control characteristics of the vane pump 100 as follows: That is, range R3 is the state where the stop member 156 is always in contact with the retainer member 152. In such a vane pump 100, the low-pressure side spring 154 is in a non-functional state from the beginning. That is, the cam ring 124 is eccentrically oriented only by the load determined by the large spring constant K2 of the high-pressure side spring 150.

[0062] Thus, in the vane pump 100, by adjusting the position of the stop member 156, the low-pressure side spring 154 can be rendered inactive from the full flow state to the full shut-off state. That is, as shown in range R3, the full shut-off pressure can be set to a higher pressure compared to range R2. Furthermore, range R3 only extends from the full flow state to the full shut-off state with a slope determined by the aforementioned spring constant K2.

[0063] Therefore, based on the vane pump 100, by using a single pump without changing the spring, it is possible to achieve... Figure 4 The pressure adjustment range, as shown in Pa-Pb, allows for complete pressure cutoff from low to high pressure over a wide range.

[0064] Furthermore, since the vane pump 100 is an integrated motor type, it is not necessary to ensure the motor for each set pressure range of the pump. Therefore, the number of types of integrated motor vane pumps, i.e., pump levels (set pressures), can be reduced, making inventory management easier and reducing costs.

[0065] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to these examples. Various modifications and alterations will be readily apparent to those skilled in the art within the scope of the claims, and these modifications and alterations also fall within the technical scope of the present invention.

Claims

1. A variable capacity vane pump, comprising: a rotor capable of rotating about a shaft; Multiple blades protrude from the rotating rotor in a sliding manner; The variable capacity vane pump is characterized by having a cam ring having an inner circumferential surface for sliding contact with the outer circumferential end of the blade protruding from the rotor, and being eccentric relative to the shaft, and having: plunger; A high-pressure side spring, which applies force to the cam ring via the plunger; Retaining element; A low-pressure side spring, which is at least partially housed in the retainer, and applies force to the cam ring via the retainer and the plunger; A stop member is provided on the end side of the low-pressure side spring opposite to the plunger side; as well as The pressure adjustment unit displaces the stop member. Even if the cam ring moves, the pressure adjustment unit can adjust the position of the stop member from a position where the retainer does not abut against the stop member to a position where the stop member is always in contact with the retainer.

2. The variable capacity vane pump according to claim 1, wherein, The pressure adjustment unit can adjust the position of the stop member to a position where the retainer never abuts against the stop member, and to a position where the retainer abuts against the stop member midway through the eccentricity of the cam ring from its maximum to zero.

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