JP4969419B2 - Variable displacement vane pump - Google Patents

Description

  The present invention relates to a variable displacement vane pump.

  There is a variable displacement vane pump as one of the variable displacement pumps that changes the discharge amount per rotation of the pump independently of the rotational speed of the drive shaft. This pump may be used as a pump for a vehicle power steering device. According to this pump, for example, when a relatively large amount of pump discharge is not required with respect to the engine speed (during high-speed running) Etc.), the discharge amount per one rotation of the pump can be reduced in accordance with the increase in the engine speed.

  This type of vane pump includes a rotor provided with a plurality of vanes in the circumferential direction, a cam ring that includes the rotor and is supported in a swingable manner in the pump body, and an eccentric amount of the cam ring with respect to the rotor axis. Some have a control valve for adjusting the pressure acting on the cam ring in order to change the discharge amount of the pump. However, when the control valve is used in this way, it is necessary to strictly manage the hydraulic oil to avoid troubles caused by contamination of the control valve, or the number of parts used for manufacturing the pump increases and the cost increases. .

  As a variable displacement vane pump without such a control valve, the load pressure is guided to the other side while the discharge pressure of the pump is guided to one side of the cam ring, and the differential pressure between the discharge pressure and the negative pressure is used for the cam ring. Some have changed the amount of eccentricity and changed the discharge amount of a pump (refer to patent documents 1 etc.).

JP 2000-104671 A

  However, in the vane pump that does not include the control valve, since the discharge pressure is directly applied to one side of the cam ring and the load pressure is directly applied to the other side, vibration of the pump is likely to occur due to fluctuations in the discharge pressure and the load pressure. It has a structure.

  An object of the present invention is to provide a variable displacement vane pump capable of reducing vibration.

  In order to achieve the above object, the present invention provides a rotor that is provided in a pump body and is driven to rotate, a plurality of vanes that are provided in a circumferential direction of the rotor so as to be able to advance and retreat in the radial direction of the rotor, A cam ring that is provided in the pump body so as to be eccentric with respect to the rotation axis, and that includes the rotor and forms a plurality of pump chambers together with the rotor and the plurality of vanes, and between the cam ring and the pump body A first fluid pressure chamber formed and reduced when the eccentric amount of the cam ring increases, a second fluid pressure chamber formed between the cam ring and the pump body, and enlarged when the eccentric amount of the cam ring increases, A pump chamber included in a plurality of pump chambers, the suction side pump chamber expanding with the rotation of the rotor and sucking the working fluid, and the plurality of pump chambers A discharge-side pump chamber that is reduced as the rotor rotates and discharges the working fluid; a discharge pipe that supplies the working fluid from the discharge-side pump chamber to an external device; and the discharge side A first flow path connecting the pump chamber and the discharge pipe, an orifice provided in the first flow path, and the discharge side pump chamber and the discharge pipe are connected via the second fluid pressure chamber. A second flow path, and a pressure adjusting unit that is provided in the second flow path and holds the pressure of the second fluid pressure chamber higher than the pressure downstream of the orifice and lower than the pressure upstream of the orifice. And a third flow path connecting the discharge-side pump chamber and the first fluid pressure chamber.

  In order to achieve the above object, the present invention provides a rotor that is provided in the pump body and is rotationally driven, and a plurality of vanes that are provided so as to advance and retract in the circumferential direction of the rotor in the radial direction of the rotor, A cam ring which is provided in the pump body so as to be eccentric with respect to the rotational axis of the rotor, and which includes the rotor and forms a plurality of pump chambers together with the rotor and the plurality of vanes; and the cam ring and the pump body A first fluid pressure chamber formed between the cam ring and the pump body, and a second fluid pressure chamber formed between the cam ring and the pump body to increase as the eccentric amount of the cam ring increases. A pump chamber included in the plurality of pump chambers, the suction-side pump chamber expanding with the rotation of the rotor and sucking a working fluid, and the plurality of pump chambers. A discharge chamber that is reduced in accordance with the rotation of the rotor and discharges the working fluid; a discharge pipe that supplies the working fluid from the discharge pump chamber to an external device; A first flow path connecting the discharge side pump chamber and the discharge pipe, an orifice provided in the first flow path, and the discharge side pump chamber and the discharge pipe via the first fluid pressure chamber; And a second flow path connecting the first fluid pressure chamber and the pressure of the first fluid pressure chamber is maintained higher than the pressure downstream of the orifice and lower than the pressure upstream of the orifice. A pressure adjusting unit; and a third flow path connecting the second fluid pressure chamber and the discharge pipe.

  According to the present invention, since the difference in pressure acting on one side and the other side of the cam ring can be reduced, generation of vibration of the pump can be suppressed.

  First, a first embodiment of the present invention will be described with reference to FIGS.

  1 is a cross-sectional view from the front of the variable displacement vane pump according to the first embodiment of the present invention during low rotation, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. Sectional drawing and FIG. 4 are DD sectional drawings in FIG.

  The variable displacement vane pump shown in these figures mainly includes a pump body 1, a rotor 11, a vane 14, a cam ring 15, and a discharge pipe 38.

  The pump body 1 includes pump components such as the rotor 11, the cam ring 15, and the compression coil spring 17, and includes a front body 10, a rear cover 19 (see FIG. 2 and the like), and an adapter 12.

  The front body 10 has a recess 90, and the rotor 11, the vane 14, the cam ring 15, the adapter 12, the pressure plate 27 (see FIG. 2) and the like are accommodated in the recess 90.

  As shown in FIG. 2, the pressure plate 27 defines a space in the recess 90 and is fitted in the recess 90. Further, the pressure plate 27 is provided with a discharge port 21 (see FIG. 1) through which the working fluid compressed in the pump chamber 18 (described later) passes. The space in the recess 90 is defined by the pressure plate 27 into a space on the rear cover 19 side and a pressure chamber 26 formed in the opposite direction. The space on the rear cover 19 side accommodates the rotor 11, the vane 14, the cam ring 15, and the adapter 12, and working fluid is introduced into the pressure chamber 26 from the pump chamber 18 (described later) via the discharge port 21. .

  The rear cover 19 is fixed to the front body 10 so as to cover a recess 90 provided in the front body 10. The rear cover 19 is provided with a suction port 22 (see FIG. 1) connected to a tank (not shown), and working fluid is supplied from the tank to a pump chamber 18 (described later) through the suction port 22. Yes.

  The adapter 12 accommodates the cam ring 15 on the inner peripheral side thereof, and is fitted in the recess 90 of the front body 10.

  The rotor 11 is rotationally driven by a shaft (drive shaft) 13 and sends hydraulic oil (working fluid) supplied between the rotor 11 and the cam ring 15 toward the discharge pipe 38. Is housed in. In addition, the rotor 11 has a plurality of slots 29 provided at predetermined intervals in the circumferential direction.

  The slots 29 are concave portions that are formed from the outer peripheral surface of the rotor 11 toward the radially inner side of the rotor 11, and the vanes 14 are inserted into the slots 29.

  The vane 14 forms a plurality of pump chambers (vane chambers) 18 (described later) between the rotor 11 and the cam ring 15, and is a slot 29 that can be advanced and retracted in the radial direction of the rotor 11 (hereinafter referred to as the rotor radial direction). Has been inserted. In the present embodiment, the pressure oil discharged from the discharge port 21 is supplied to the inner side (in the shaft 13 side) in the rotor 29 in the slot 29 via a pressure chamber 26 (described later), and the vane 14 is moved in the rotor radial direction. Pushing outward. As a result, the outer end portion of the vane 14 in the radial direction of the rotor moves while contacting the inner peripheral surface of the cam ring 15.

  The shaft 13 is for transmitting a driving force supplied from a prime mover or the like to the rotor 11, and is connected to the rotor 11. The shaft 13 is supported by a bearing 28 provided on the front body 10 and a bearing 95 provided on the rear cover 19, and is disposed so as to penetrate the front body 10.

  The cam ring 15 changes the discharge amount (pump volume) of the pump by being eccentric with respect to the rotation axis of the rotor 11 (axis of the shaft 13), and is provided inside the adapter 12. The cam ring 15 is attached to the adapter 12 via a support pin 16 provided on the outer peripheral side thereof, and is supported by the support pin 16 so as to be swingable within the adapter 12. The cam ring 15 of the present embodiment is cam ring in a direction in which the amount of eccentricity of the cam ring with respect to the rotational axis of the rotor 11 (hereinafter referred to as the amount of eccentricity of the cam ring) increases (to the left in FIG. 1 in the present embodiment). The urging mechanism 17 urges 15. In this embodiment, a compression coil spring is used as the urging mechanism 17, but the cam ring 15 may be urged using a cylinder or the like.

  A first fluid pressure chamber 40 and a second fluid pressure chamber 41 are formed in the space between the cam ring 15 and the adapter 12.

  The volume of the first fluid pressure chamber 40 decreases as the amount of eccentricity of the cam ring 15 increases, and is provided on one side of the cam ring 15 (left side in FIG. 1). The volume of the second fluid pressure chamber 41 increases as the amount of eccentricity of the cam ring 15 increases, and is provided on the other side (right side in FIG. 1) of the cam ring 15. The working fluid is introduced into the first fluid pressure chamber 40 through a through hole 45 (described later), and the second fluid pressure chamber 41 is introduced through a first throttle 50 and a passage 82 (described later). The working fluid introduced into the chambers 40 and 41 exerts pressure on the cam ring 15. In the present embodiment, when the force generated by the pressure difference between the first fluid pressure chamber 40 and the second fluid pressure chamber 41 exceeds the sum of the urging force by the urging mechanism 17 and the force by the hydraulic pressure inside the cam ring 15, the amount of eccentricity is increased. The cam ring 15 moves in the direction in which the angle decreases. Thus, the cam ring 15 is accommodated in the pump body 1 so as to be eccentric with respect to the rotational axis of the rotor 11.

  On the other hand, in the space between the cam ring 15 and the rotor 11, a plurality of pump chambers (vane chambers) 18 are formed by the inner peripheral surface of the cam ring 15, the outer peripheral surface of the rotor 11, and the vanes 14. The volume of each pump chamber 18 changes according to the rotation of the rotor 11 and the eccentric amount of the cam ring 15. Thereby, the space formed between the cam ring 15 and the rotor 11 is roughly divided into a region where the volume of the pump chamber 18 increases as the rotor 11 rotates and a region where the volume decreases. A suction port 22 is opened in a region where the volume increases as the rotor 11 rotates, and a working fluid is supplied to the pump chamber 18 located in this region. On the other hand, the discharge port 21 is opened in a region where the volume is reduced, and the working fluid is discharged from the pump chamber 18 located in this region toward the pressure chamber 26. Here, the pump chamber 18 positioned in a region where the volume increases with the rotation of the rotor 11 is referred to as a suction side pump chamber 85, and the pump chamber 18 positioned in a region where the volume decreases is referred to as a discharge side pump chamber 86. In FIG. 1, the suction side pump chamber 85 is located in the upper half of the space formed between the cam ring 15 and the rotor 11, and the discharge side pump chamber 86 is located in the lower half of the space.

  The discharge pipe 38 supplies the working fluid from the pump chamber 18 to an external device, and protrudes from the pump body 1. Examples of the external device include a device such as a power cylinder, and more specifically, a vehicle power steering device, a CVT (Continuously Variable Transmission), and the like.

  Next, the flow path connecting each component will be described with reference to FIGS. 1 and 3.

  The vane pump of the present embodiment connects the discharge side pump chamber 86 and the discharge pipe 38 via the first flow path 91 that connects the discharge side pump chamber 86 and the discharge pipe 38 and the second fluid pressure chamber 41. A second flow path 92, a third flow path 93 (see FIG. 6 later) for connecting the discharge-side pump chamber 86 and the first fluid pressure chamber 40 are provided.

  The first flow path 91 supplies the working fluid from the pump chamber 18 to the discharge pipe 38 via the metering orifice 23, and includes the discharge port 21, the pressure chamber 26, the metering orifice 23, and the passage. 87. The passage 87 is a passage connecting the pressure chamber 26 and the discharge pipe 38, and the metering orifice 23 is provided between the passage 87 and the pressure chamber 26.

  The second flow path 92 introduces an intermediate pressure between the discharge pressure and the load pressure of the pump into the second fluid pressure chamber 41. The discharge port 21, the pressure chamber 26, the first throttle 50 (see FIG. 1), and The second fluid pressure chamber 41, the passage 82, the second throttle 51, and the passage 88 are formed.

  The first throttle 50 is a through hole provided in the pressure plate 27, and the working fluid from the pressure chamber 26 circulates therethrough. The passage 82 is a passage connecting the second fluid pressure chamber 41 and the second throttle 51, and the passage 88 is a passage connecting the second throttle 51 and the discharge pipe 38. The second diaphragm 51 is provided between the passage 82 and the passage 88.

  A passage 83 is connected to the passage 82 of the present embodiment. The passage 83 is a flow path connected to the passage 82 so as to be positioned between the second fluid pressure chamber 41 and the second throttle 51, and the pressure relief valve (hereinafter referred to as relief valve) 32 (see FIG. 4) is provided in the passage 83. ) Is installed.

  As shown in FIG. 4, the relief valve 32 includes a seat portion 32a, a ball 32b, a retainer 32c, and a spring 32d. When the pressure in the passage 83 reaches a set value or more determined by the spring 32d, the ball 32b and the retainer 32c are integrated to operate in the direction of opening the seat portion 32a (left direction in FIG. 4), and a tank (not shown) The passage 46 and the passage 83 connected to each other are connected. According to the relief valve 32 configured in this way, even if excessive pressure is applied to the passage 82, excess working fluid can be discharged to the outside, so that the pressure in the passage 82 is kept within the set value range. be able to.

  The third flow path 93 supplies the working fluid from the pump chamber 18 toward the first fluid pressure chamber 40, and is formed by the discharge port 21, the pressure chamber 26, and the through hole 45 (see FIG. 1). ing. The through hole 45 is a hole provided in the pressure plate 27 and connects the pressure chamber 26 and the first fluid pressure chamber 40.

  Next, the operation of the variable displacement vane pump according to the present embodiment will be described.

  FIG. 5 is a graph showing the relationship between the rotational speed and the discharge flow rate of the variable displacement vane pump according to the first embodiment of the present invention.

  In the vane pump configured as described above, when a rotational driving force is input from the shaft 13, the vane 14 rotates while contacting the cam ring 15 to increase or decrease the volume of each pump chamber 18. In the section where the volume increases (suction side pump chamber 85), the pressure in the pump chamber 18 decreases, and the working fluid from the tank is sucked in via the suction port 22. The working fluid sucked into the pump chamber 18 is pressurized as the volume of the pump chamber 18 decreases in a section (discharge-side pump chamber 86) that is not connected to the tank or the pressure chamber 26. The pressurized working fluid is guided to the pressure chamber 26 through the discharge port 21 as the volume of the pump chamber 18 is reduced. The working fluid guided to the pressure chamber 26 passes through the first flow path 91, the second flow path 92, and the third flow path 93, and the discharge pipe 38, the first fluid pressure chamber 40, and the second fluid pressure chamber. 41.

  The working fluid in the first flow path 91 is discharged from the pressure chamber 26 at the discharge pressure (P1), and is reduced to the load pressure (P3) through the orifice 23, and then supplied to the discharge pipe 38.

  In the third flow path 93, the working fluid discharged from the pressure chamber 26 at the discharge pressure (P 1) is guided to the first fluid pressure chamber 40, and the discharge pressure ( P1) is activated.

  On the other hand, the pressure in the second flow path 92 is maintained at the discharge pressure (P1) upstream of the first throttle 50 and at the load pressure (P3) downstream of the second throttle 51. In a region sandwiched between the second throttles 51 (second fluid pressure chamber 41, passage 82, passage 83), a value between the discharge pressure P1 and the load pressure P3 (hereinafter, referred to as the first throttle 50 and the second throttle 51). The intermediate pressure (P2) is maintained (P1> P2> P3)). Thereby, the working fluid of the intermediate pressure (P2) is introduced into the second fluid pressure chamber 41, and the intermediate pressure (P2) is applied to the cam ring 15 in the direction in which the eccentric amount increases.

  As described above, the cam ring 15 includes the discharge pressure (P1) from the first fluid pressure chamber 40, the intermediate pressure (P2) from the second fluid pressure chamber 41, the urging force from the urging mechanism 17 and the cam ring 15. Since the sum (reaction force) (f0) of the force due to the internal oil pressure acts, the eccentric amount of the cam ring 15 is the force (F) and reaction force (f0) due to the differential pressure (P1-P2) between the discharge pressure and the intermediate pressure. It will be controlled by the magnitude relationship.

  Here, in the case of a fixed capacity region (see FIG. 5) where the rotational speed of the pump is low, the pressure loss at the orifice 23 and the pressure loss at the first throttle 50 and the second throttle 51 are small because the pump discharge amount is small. small. Therefore, the force (F) due to the differential pressure (P1-P2) cannot exceed the reaction force (f0), and the cam ring 15 is held at the position where the eccentric amount is maximum by the urging mechanism 17, and the pump displacement is fixed. The As a result, the pump discharge amount increases with the rotational speed as shown in FIG.

  However, as the rotational speed of the pump increases, the flow rate of the working fluid discharged from the discharge port 21 increases, and the metering orifice 23, the first throttle 50, and the second throttle compared to the case of a low rotational speed. The pressure loss at 51 increases. As a result, the force (F) due to the differential pressure (P1-P2) between the discharge pressure and the intermediate pressure also increases, so that the force for swinging the cam ring 15 in the direction of decreasing the eccentric amount against the biasing mechanism 17 increases. . When the number of rotations of the pump further increases and reaches the variable displacement range (see FIG. 5), the cam ring 15 begins to swing in the direction in which the eccentric amount decreases due to the increase in the differential pressure (P1-P2), as shown in FIG. In this way, the discharge flow rate per rotation decreases.

  As described above, according to the present embodiment, when the rotation speed of the pump exceeds the fixed capacity range, it is possible to prevent the discharge flow rate from increasing even if the rotation speed increases thereafter, and the rotation speed applied to the shaft 13. And the discharge flow rate can be controlled as shown in FIG.

  In particular, in the present embodiment, since the second fluid pressure chamber 41 is provided between the first throttle 50 and the second throttle, it is compared with the case where the load pressure (P3) is introduced into the second fluid pressure chamber 41. Thus, the force acting on the second fluid pressure chamber 41 can be reduced by the difference (P2−P3) between the load pressure (P3) and the intermediate pressure (P2). As a result, the sudden inflow and outflow of the working fluid in the second fluid pressure chamber 41 is suppressed, so that it is possible to suppress the occurrence of rapid pressure fluctuations in the second fluid pressure chamber 41. That is, according to the present embodiment, the vibration phenomenon of the cam ring 15 can be suppressed as compared with the case where the load pressure (P3) is introduced into the second fluid pressure chamber 41, so that the vibration of the pump is suppressed. be able to.

  In the vane pump, when the load pressure (P3) increases and the force due to the load pressure (P3) becomes higher than the force of the spring 32d of the relief valve 32, the relief valve 32 opens. When the relief valve 32 is opened, the working fluid discharged from the pressure chamber 26 is returned to the tank through the relief valve 32. At this time, the pressure chamber 26 operates in a flow path through the metering orifice 23, the second throttle 51, and the relief valve 32, and a flow path through the first throttle 50, the second fluid pressure chamber 41, and the relief valve 32. Fluid is returned to the tank. The pressure loss in the first throttle 50 due to this flow decreases the pressure in the second fluid pressure chamber 41, so the pressure difference between the first fluid pressure chamber 40 and the second fluid pressure chamber 41 increases and the eccentricity of the cam ring 15. The cam ring can be swung in the direction to decrease the discharge flow rate, and the discharge flow rate per rotation can be reduced.

  Next, the effect of the variable displacement vane pump of the present embodiment will be described with reference to a comparative example.

  As a comparative example of the vane pump of the present embodiment, a variable displacement vane pump that does not have a control valve that adjusts the pressure acting on the cam ring, the discharge pressure of the pump is guided to one side of the cam ring, and the other side is Some have led to the load pressure (see Patent Document 1). In this vane pump, the amount of discharge of the pump is changed by changing the amount of eccentricity using the differential pressure between the discharge pressure introduced to the cam ring and the negative pressure.

  However, in this type of vane pump, since the discharge pressure is directly applied to one side of the cam ring and the load pressure is directly applied to the other side, the pressure difference acting on the cam ring is large. When the pressure difference is large in this way, the cam ring easily moves due to sudden pressure fluctuations (pulse pressure or the like), so that the vibration of the pump is likely to occur.

  In contrast to such a comparative example, the variable displacement vane pump of the present embodiment is located upstream of the second fluid pressure chamber 41 with respect to the second flow path 92 that supplies the working fluid to the second fluid pressure chamber 41. The first throttle 50 provided so as to be located on the second fluid pressure chamber 41 and the second throttle 51 provided on the downstream side of the second fluid pressure chamber 41. When the second fluid pressure chamber 41 is provided between the first throttle 50 and the second throttle 51 in this way, the pressure value of the working fluid introduced into the second fluid pressure chamber 41 is maintained between the discharge pressure and the load pressure. Therefore, compared with the comparative example in which the discharge pressure and the load pressure are directly applied to the outer periphery of the cam ring, it is possible to reduce the influence of pressure fluctuations such as pulse pressure. Thereby, even when the discharge pressure and the load pressure fluctuate rapidly, it is possible to suppress the cam ring 15 from swinging more easily than in the comparative example, and thus it is possible to suppress the occurrence of vibration of the pump. .

  In the above description, the second flow path 92 is configured by the first throttle 50 provided in the pressure plate 27 and the second throttle 51 provided in the rear cover 19, but the pressure in the second fluid pressure chamber 41 is set to the load pressure. Any configuration may be used as long as a pressure adjusting unit is formed that holds the intermediate pressure (P2) higher than (P3) and lower than the discharge pressure (P1). That is, as shown in FIG. 6 in which a part of the configuration of the variable displacement vane pump according to the first embodiment of the present invention is shown as a hydraulic circuit, the above embodiment is similar to that shown as a hydraulic circuit. It only has to be configured.

  Here, a specific modification of the first diaphragm 50 will be described with reference to FIGS. 7 and 8. FIG. 7 is a diagram in which the first modification of the first throttle 50 is applied to the variable displacement vane pump according to the first embodiment of the present invention, and FIG. 8 is a diagram in which the second modification of the first throttle 50 is also applied. It is. In addition, the same code | symbol is attached | subjected to the same part as the previous figure, and description is abbreviate | omitted (the following figure is also the same).

  In the first modification shown in FIG. 7, a groove 47 a that connects the discharge port 21 and the second fluid pressure chamber 41 is provided in the pressure plate 27. In the second modified example shown in FIG. 8, a groove 48 a that connects the discharge-side pump chamber 86 and the second fluid pressure chamber 41 is provided in the cam ring 15. Even if a flow path corresponding to the first throttle 50 is formed as in these modified examples, the pressure in the second fluid pressure chamber 41 can be maintained at the intermediate pressure (P2), so the same effect as described above can be obtained. Obtainable. Note that the pressure adjusting unit may be configured by using a pressure control valve instead of the throttle 50 and the grooves 47a and 48a.

  The third channel 92 may be formed as follows. 7 and 8, as an alternative flow path for the third flow path 92, a groove 47b (see FIG. 7) provided in the discharge port 21 and a groove 48b (see FIG. 8) provided in the cam ring 15 are provided. It has been. The groove 47 b and the groove 48 b connect the discharge side pump chamber 86 and the first fluid pressure chamber 40. If the discharge-side pump chamber 86 and the first fluid pressure chamber 40 are connected in this manner, a flow path equivalent to the third flow path 92 can be configured.

  Next, a second embodiment of the present invention will be described.

  FIG. 9 is a cross-sectional view from the front of the variable displacement vane pump according to the second embodiment of the present invention during low rotation, and FIG. 10 is a diagram showing a part of the configuration with a hydraulic circuit.

  The variable displacement vane pump according to the present embodiment supplies the working fluid to the discharge pipe 38 from the discharge side pump 86 via the first fluid pressure chamber 40, and introduces the load pressure into the second fluid pressure chamber 41. This is different from the first embodiment.

  The variable displacement vane pump shown in FIG. 9 replaces the second flow path 92 and the third flow path 93 in the first embodiment with the discharge side pump chamber 86 and the discharge piping via the first fluid pressure chamber 40. A second flow path 92A for connecting the gas flow passage 38 and a third flow path 93A for connecting the second fluid pressure chamber 41 and the discharge pipe 38 are provided.

  The second flow path 92A introduces an intermediate pressure between the discharge pressure and the load pressure of the pump into the first fluid pressure chamber 40. The discharge port 21, the pressure chamber 26, the first throttle 55, and the first fluid The pressure chamber 40, the second throttle 60, the passage 95, and the passage 87 are formed.

  The first throttle 55 is a through hole provided in the pressure plate 27, and the working fluid from the pressure chamber 26 circulates therethrough. The second throttle 60 is a through hole provided in the adapter 12 and connects the first fluid pressure chamber 40 and the passage 95. The passage 95 connects the second throttle 60 and the passage 87, and is connected to the passage 87 on the downstream side of the orifice 23.

  The third flow path 93A introduces a working fluid having a load pressure into the second fluid pressure chamber 41, and is formed by the second fluid pressure chamber 41, the passage 96, the third throttle 56, and the passage 97. Yes. The passage 96 is a passage connecting the second fluid pressure chamber 41 and the third throttle 56, and the passage 97 is a passage connecting the third throttle 56 and the passage 87. The third diaphragm 56 is provided between the passage 96 and the passage 97. A passage 83 provided with a relief valve 32 is connected to the passage 96, and the pressure in the passage 96 is suppressed within a set range by the relief valve 32.

  According to the variable displacement vane pump of the present embodiment configured as described above, the working fluid from the discharge pipe 38 passes through the passage 97, the third throttle 56, and the passage 96 in the third flow path 93A. 41, the load pressure (P3) acts on the cam ring 15 in the direction in which the amount of eccentricity decreases (left direction in FIG. 10). In the second flow path 92A, the working fluid having an intermediate pressure (P2) is guided to the first fluid pressure chamber 40 located in a region sandwiched between the first throttle 55 and the second throttle 60. As a result, the intermediate pressure (P2) acts on the cam ring 15 in the direction in which the amount of eccentricity increases (the right direction in FIG. 10). Accordingly, the cam ring 15 has a reaction force (f1) such as an intermediate pressure (P2) from the first fluid pressure chamber 40, a load pressure (P3) from the second fluid pressure chamber 41, and a biasing force from the biasing force mechanism 17. Therefore, the amount of eccentricity of the cam ring 15 is controlled by the magnitude relationship between the force (F) and the reaction force (f1) due to the differential pressure (P2-P3) between the intermediate pressure and the load pressure.

  Therefore, when the rotation speed of the pump increases and the pressure loss in the metering orifice 23, the first throttle 55, and the second throttle 60 increases, the force (P2-P3) due to the differential pressure between the intermediate pressure and the load pressure (P2-P3) Since F) also increases, the force for swinging the cam ring 15 in the direction of decreasing the amount of eccentricity against the biasing mechanism 17 increases. Thus, as in the first embodiment, when the rotational speed of the pump exceeds the fixed capacity range, the discharge flow rate can be prevented from increasing even if the rotational speed increases thereafter. Also in the present embodiment, since the force acting on the first fluid pressure chamber 40 can be reduced as compared with the case where the discharge pressure (P1) is introduced into the first fluid pressure chamber 40, the first fluid pressure chamber The rapid inflow and outflow of the working fluid to 40 can be suppressed. Thereby, the vibration phenomenon of the cam ring 15 can be reduced, so that the vibration of the pump can be suppressed.

  In the present embodiment, it is sufficient that the hydraulic circuit shown in FIG. 10 is configured. Therefore, like the first throttle 50 in the first embodiment, the first throttle 55 has a groove in the pressure plate 27. The cam ring 15 may be provided with a hole or a groove, or the like.

  Next, a third embodiment of the present invention will be described. The variable displacement vane pump of this embodiment is different from that of the first embodiment in that the discharge flow rate of the pump is controlled by a variable control mechanism that variably controls the flow passage area of the second throttle 51.

  FIG. 11 is a configuration diagram of a variable displacement vane pump according to a third embodiment of the present invention. FIGS. 12 and 13 illustrate a fixed displacement region and a variable displacement vane pump according to a third embodiment of the present invention. It is a figure which shows the change of a variable capacity area.

  The variable displacement vane pump shown in this figure includes a solenoid valve 70 that variably controls the flow passage area of the second throttle 51 and a control device 53 that controls the current supplied to the solenoid valve 70.

  The solenoid valve 70 includes a coil, a fixed iron core (both not shown), a plunger (movable iron piece) 71, and the like. The plunger 71 operates in a direction (left direction in FIG. 11) in which the flow path area of the second throttle 51 is reduced by an electromagnetic force generated when a current flows through the coil. The operation amount of the plunger 71 is controlled by the magnitude of the current supplied to the coil of the solenoid valve 70.

  The control device 53 calculates an energization amount (command current amount) to the solenoid valve 70 based on an input signal from the outside (sensor or the like), and energizes the solenoid valve 70 with the calculated amount of current. For example, as a sensor used when the external device (the connection destination of the discharge pipe 38) is a power steering device, as shown in FIG. 11, a snake angle sensor 72 that transmits a snake angle or a vehicle speed sensor that transmits a vehicle speed. There are 73. In this case, an appropriate flow path area (opening amount) is calculated by the control device 53 based on the snake angle and input signals from the vehicle speed sensors 72 and 73, and a current corresponding to the flow path area is supplied to the solenoid valve 70. What is necessary is just to set it as the structure which supplies with electricity. With this configuration, for example, it is possible to control the engine speed and the discharge flow rate independently, for example, to reduce the discharge flow rate of the vane pump during high-speed traveling, so that only the minimum necessary flow rate is discharged from the vane pump. Energy efficiency can be improved. Note that an input signal from another sensor such as a hydraulic pressure sensor or an oil temperature sensor may be used according to the control mode.

  When the flow path area of the second throttle 51 is changed by the solenoid valve 70, the flow rate of the working fluid passing through the second flow path 92 changes, so the pressure difference (P1-P2) before and after the first throttle 50 is changed. be able to. For example, when the plunger 71 moves in a direction in which the flow path area decreases, the flow path of the working fluid passing through the second flow path 92 decreases relatively, and the pressure difference before and after the first throttle 50 is relatively small. Become. This means that the pressure difference (P1−P2) between the first fluid pressure chamber 40 and the second fluid pressure chamber 41 becomes relatively small, and therefore, the amount of eccentricity is reduced against the biasing mechanism 17. The force for swinging the cam ring 15 is relatively small. Therefore, when the flow passage area of the second throttle 51 is reduced by the solenoid valve 70, the fixed capacity area of the pump can be relatively widened as shown in FIG. Further, when viewed at a certain rotation speed, the discharge flow rate at that rotation speed can be increased. In addition, when the flow path area of the 2nd aperture_diaphragm | restriction 51 is enlarged, the fixed capacity area | region of a pump can be made relatively small by the effect | action contrary to the above (refer FIG. 13).

  Further, in the present embodiment configured as described above, the two flow paths of the first flow path 91 and the second flow path 92 are provided as flow paths that flow from the discharge side pump chamber 86 to the discharge pipe 38 (load side). Therefore, the flow rate of the working fluid in the second flow path 92 is smaller than the flow rate in the first flow path 91. Therefore, when the variable control mechanism for the flow path area is provided in the second throttle 51 as described above, the force required for the flow path area control is reduced as compared with the case where the variable control mechanism is provided for the orifice 23. be able to. Thereby, compared with the case where the solenoid valve is provided in the orifice 23, the amount of current applied to the solenoid valve 70 can be reduced, and the energy efficiency in the flow path area control can be improved. Further, since the force required for the flow path area control is reduced, it is possible to cope with a small solenoid valve, so that the vane pump can be miniaturized. Furthermore, when there is an upper limit to the driving force that can be applied to the solenoid valve 70, the control flow width can be made larger than when the solenoid valve is provided in the orifice 23.

  By the way, although there is a difference in the amount of electricity required to drive the solenoid valve, a pump that changes the discharge flow rate even if a variable control mechanism that variably controls the flow area of the first throttle 50 and the metering orifice 23 is provided. Can be configured.

  For example, when the flow path area of the first aperture 50 is variable, the flow area of the first aperture 50 is increased as the command current amount is increased. The pressure difference between the first fluid pressure chamber 40 and the second fluid pressure chamber 41 becomes relatively small. As a result, the force (F) for decentering the cam ring 15 becomes relatively small, so that the fixed capacity region can be relatively widened as described above. Moreover, if it controls so that the flow-path area of the 1st aperture 50 may be increased with a certain rotation speed, the discharge flow rate in the rotation speed can be increased.

  Further, when the flow passage area of the metering orifice 23 is variable, the first flow passage area of the orifice 23 is increased when the flow passage area of the orifice 23 is increased as the command current amount is increased. Since the pressure difference between the fluid pressure chamber 40 and the second fluid pressure chamber 41 becomes small, the same effect as described above can be obtained.

  In the above description, the solenoid valve is taken as an example of the variable flow area control mechanism. However, other mechanisms such as a variable throttle and a flow control valve may be used as appropriate.

  Further, in the above configuration, in consideration of the case where an abnormality occurs due to a failure in the control device 53 or the solenoid valve 70 and a state where it is impossible to energize despite the desire to control the solenoid valve 70, the solenoid as described below is taken into consideration. The valve 70 is preferably configured.

  For example, when control is performed so that the flow passage area of the second throttle 51 becomes smaller in accordance with an increase in the amount of current supplied to the solenoid valve 70, the flow passage area when the current supply to the solenoid valve 70 becomes impossible. Works in the direction of enlargement. Accordingly, in order to ensure the minimum function of the vane pump even if an abnormality occurs, the flow area of the second throttle 51 is allowed to be the design specification of the external device (the working fluid supply destination of the vane pump) when not energized. The solenoid valve 70 may be provided so as to reach the maximum value. When the solenoid valve 70 is configured in this manner, the pump discharge flow rate is reduced as compared with the normal state when an abnormality occurs, but the minimum function of the variable displacement vane pump can be ensured.

  Contrary to the above, when the flow passage area of the second throttle 51 is increased in accordance with the increase in the energization amount to the solenoid valve 70, the flow of the second throttle 51 is in the non-energized state. The solenoid valve 70 may be provided so that the road area reaches the minimum value allowed by the design specifications of the external device. When the solenoid valve 70 is configured in this way, the discharge flow rate of the pump increases from the normal state when an abnormality occurs, but the minimum function of the variable displacement vane pump can be ensured.

  Here, the solenoid valve 70 for controlling the flow area of the second throttle 51 has been described as an example, but the above configuration is also applied when the flow area of the orifice 23 and the first throttle 50 is controlled. be able to.

  By the way, considering the case where the above-described configuration is further expanded and an abnormality such as a failure occurs in the control device 53 or the solenoid valve 70, and a state where the solenoid valve 70 is always energized despite the desire to control the solenoid valve 70 is considered. Thus, the solenoid valve 70 is preferably configured as described below. This case will be described as a fourth embodiment with reference to FIG.

  FIG. 14 is a configuration diagram of a variable displacement vane pump according to the fourth embodiment of the present invention.

  The variable displacement vane pump shown in this figure is different from that of the third embodiment in that an emergency control device 80 is provided. The emergency control device 80 forcibly cuts off the energization to the solenoid valve 70 when it detects an energization amount to the solenoid valve 70 or an abnormality of the control device 53, and is connected to the solenoid valve 70 and the control device 53. ing. From the control device 53, the control device 53 to the emergency control device 80 receive a signal (state detection signal 81 (for example, command content (energization amount) to the solenoid valve 70) or the like) that can detect the operating state of the control device 53. Have been entered. Further, the solenoid valve 70 receives a state detection signal 82 (for example, an operation amount of the solenoid valve 70) of the solenoid valve 70 from the solenoid control unit 80.

  In the present embodiment configured as described above, the emergency control device 80 is based on the state detection signals 80a and 80b from the control device 53 and the solenoid valve 70, and the operating state of the control device 53 and the solenoid valve 70 is abnormal. Determine if there is any. If the emergency control device 80 detects that there is an abnormality in the control device 53 or the solenoid valve 70 by finding a contradiction in the operating state of each device that can be determined from the state detection signals 80a and 80b, the emergency control device 80 returns to the solenoid valve 70. Is output to the solenoid valve 70 (current cutoff signal 80c). Since the solenoid valve 70 is in a non-energized state by the current cut-off signal 80c, the flow path area of the second throttle 51 is held at the maximum value (or minimum value) set in the third embodiment. As described above, according to the present embodiment, the solenoid valve 70 can be controlled even when a current is constantly supplied to the solenoid valve 70, so that the function of the vane pump can be secured at a minimum.

  In the above description, the control for cutting off the current based on the energization state of the solenoid valve 70 has been described. However, the energization to the solenoid valve 70 may be forcibly cut off based on other factors. . Further, not only the second throttle 51 but also the emergency control device 80 may be used when the energization of the variable control mechanism of the first throttle 50 and the orifice 23 is forcibly cut off.

  In the third and fourth embodiments described above, which throttle channel area is variable or whether the channel area is increased or decreased in accordance with an increase in current depends on the design specifications. And change it.

  Furthermore, in the above description of the third and fourth embodiments, the case where the solenoid valve 70 or the like is applied to the vane pump described in the first embodiment has been described. However, the vane pump according to the second embodiment is described. Also available. That is, even if the solenoid valve 70 is applied to the first throttle 55, the second throttle 60, and the orifice 23 in the vane pump according to the second embodiment, the same effect as described above can be exhibited.

  Next, a fifth embodiment of the present invention will be described.

  FIG. 15 is a configuration diagram of a variable displacement vane pump according to the fifth embodiment of the present invention.

  The variable displacement vane pump of the present embodiment is an application of the vane pump of the third embodiment to CVT. The CVT is composed of a primary pulley and a secondary pulley whose diameter can be changed, and a belt wound around the primary pulley and the secondary pulley. In CVT, the pulley diameter is changed by the oil pressure, and the rotation ratio between the engine rotation side and the axle rotation side is changed. Therefore, the variable displacement vane pump of the present embodiment can be used as a supply source of the oil pressure. .

  The variable displacement vane pump control device 53A shown in this figure is connected to a selection range sensor 75, a throttle opening sensor 76, and a vehicle speed sensor 77. The control device 53A calculates a flow area (opening amount) suitable for the traveling state based on input signals from the selection range sensor 75, the throttle opening sensor 76, and the vehicle speed sensor 77, and a current corresponding to the flow area. The solenoid valve 70 is energized.

  By configuring the variable displacement vane pump in this way, it is possible to send the pressure oil at a flow rate according to the CVT requirement independently of the engine speed, thereby improving energy efficiency. In this case as well, input signals from other sensors such as a hydraulic pressure sensor and an oil temperature sensor may be used depending on the mode of control.

The sectional view from the front at the time of low rotation of the variable capacity type vane pump concerning a 1st embodiment of the present invention. AA sectional drawing in FIG. BB sectional drawing in FIG. DD sectional drawing in FIG. The relationship diagram of the rotation speed and discharge flow rate of the variable displacement vane pump according to the first embodiment of the present invention. The figure which shows a part of structure of the variable displacement vane pump which concerns on the 1st Embodiment of this invention with a hydraulic circuit. The figure which applied the 1st modification of the 1st aperture 50 to the variable capacity type vane pump concerning a 1st embodiment of the present invention. The figure which applied the 2nd modification of the 1st aperture 50 to the variable capacity type vane pump concerning a 1st embodiment of the present invention. Sectional drawing from the front at the time of the low rotation of the variable displacement vane pump which concerns on the 2nd Embodiment of this invention. The figure which shows a part of structure of the variable displacement vane pump which concerns on the 2nd Embodiment of this invention with a hydraulic circuit. The block diagram of the variable displacement vane pump which concerns on the 3rd Embodiment of this invention. The figure which shows the change of the fixed capacity | capacitance area | region and variable capacity area | region in the variable capacity | capacitance type vane pump which concerns on the 3rd Embodiment of this invention. The figure which shows the change of the fixed capacity | capacitance area | region and variable capacity area | region in the variable capacity | capacitance type vane pump which concerns on the 3rd Embodiment of this invention. The block diagram of the variable displacement vane pump which concerns on the 4th Embodiment of this invention. The block diagram of the variable displacement vane pump which concerns on the 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pump body 11 Rotor 13 Shaft 14 Vane 15 Cam ring 17 Compression coil spring (biasing mechanism)
18 Pump chamber 21 Discharge port 22 Suction port 23 Metering orifice 29 Slot 32 Relief valve 38 Discharge piping 40 First fluid pressure chamber 41 Second fluid pressure chamber 50 First restrictor 51 Second restrictor 53 Control device 55 First restrictor 60 First 2 throttle 70 Solenoid valve 80 Emergency control device 85 Suction side pump chamber 86 Discharge side pump chamber 90 Recess 91 First flow path 92 Second flow path 93 Third flow path 95 Bearing

Claims (28)

A rotor provided in the pump body and driven to rotate;
A plurality of vanes provided in the circumferential direction of the rotor so as to be capable of moving back and forth in the radial direction of the rotor;
A cam ring which is provided in the pump body so as to be eccentric with respect to the rotation axis of the rotor, and which includes the rotor and forms a plurality of pump chambers together with the rotor and the plurality of vanes;
A first fluid pressure chamber formed between the cam ring and the pump body, wherein the first fluid pressure chamber decreases as the eccentric amount of the cam ring increases;
A second fluid pressure chamber formed between the cam ring and the pump body and expanding as the amount of eccentricity of the cam ring increases;
A pump chamber included in the plurality of pump chambers, wherein the suction side pump chamber expands with the rotation of the rotor and sucks the working fluid; and
A pump chamber included in the plurality of pump chambers, wherein the discharge chamber is reduced with the rotation of the rotor and discharges the working fluid;
A discharge pipe for supplying the working fluid from the discharge-side pump chamber to an external device;
A first flow path connecting the discharge side pump chamber and the discharge pipe;
An orifice provided in the first flow path;
A second flow path connecting the discharge-side pump chamber and the discharge pipe via the second fluid pressure chamber;
A first throttle provided in the second flow path so as to be located upstream of the second fluid pressure chamber;
A second throttle provided in the second flow path so as to be located downstream of the second fluid pressure chamber;
A variable displacement vane pump comprising a third flow path connecting the discharge-side pump chamber and the first fluid pressure chamber. The variable displacement vane pump according to claim 1,
The variable displacement vane pump further comprising a variable control mechanism that variably controls the flow passage area of the second throttle. The variable displacement vane pump according to claim 2,
The variable displacement vane pump, wherein the variable control mechanism is a solenoid valve. The variable displacement vane pump according to claim 3,
The variable displacement vane pump, wherein the solenoid valve is provided so that a flow passage area of the second throttle is minimized when in a non-energized state. The variable displacement vane pump according to claim 3,
The variable displacement vane pump, wherein the solenoid valve is provided so that a flow passage area of the second throttle is maximized in a non-energized state. The variable displacement vane pump according to claim 3,
A variable displacement vane pump, further comprising: a controller that calculates an energization amount to the solenoid valve based on an input signal from the outside and energizes the solenoid valve with the calculated amount of current. The variable displacement vane pump according to claim 6,
A variable displacement vane pump, further comprising an emergency control device that minimizes the flow area of the second throttle when an energization amount to the solenoid valve or an abnormality of the control device is detected. The variable displacement vane pump according to claim 6,
A variable displacement vane pump, further comprising: an emergency control device that maximizes a flow passage area of the second throttle when an energization amount to the solenoid valve or an abnormality of the control device is detected. The variable displacement vane pump according to claim 1,
A variable displacement vane pump, further comprising a variable control mechanism that variably controls the flow path area of the orifice. The variable displacement vane pump according to claim 1,
The variable displacement vane pump further comprising a variable control mechanism that variably controls the flow path area of the first throttle. The variable displacement vane pump according to claim 1,
A pressure relief valve provided in the second flow path so as to be positioned between the second fluid pressure chamber and the second throttle and discharging the working fluid to the outside when the pressure in the passage reaches a set value or more. A variable displacement vane pump characterized by further comprising: The variable displacement vane pump according to claim 1,
2. The variable displacement vane pump according to claim 1, wherein the external device is a CVT. The variable displacement vane pump according to claim 1,
The variable capacity vane pump, wherein the external device is a power steering device. A rotor provided in the pump body and driven to rotate;
A plurality of vanes provided in the circumferential direction of the rotor so as to be capable of moving back and forth in the radial direction of the rotor;
A cam ring which is provided in the pump body so as to be eccentric with respect to the rotation axis of the rotor, and which includes the rotor and forms a plurality of pump chambers together with the rotor and the plurality of vanes;
A first fluid pressure chamber formed between the cam ring and the pump body, wherein the first fluid pressure chamber decreases as the eccentric amount of the cam ring increases;
A second fluid pressure chamber formed between the cam ring and the pump body and expanding as the amount of eccentricity of the cam ring increases;
A pump chamber included in the plurality of pump chambers, wherein the suction side pump chamber expands with the rotation of the rotor and sucks the working fluid; and
A pump chamber included in the plurality of pump chambers, wherein the discharge chamber is reduced with the rotation of the rotor and discharges the working fluid;
A discharge pipe for supplying the working fluid from the discharge-side pump chamber to an external device;
A first flow path connecting the discharge side pump chamber and the discharge pipe;
An orifice provided in the first flow path;
A second flow path connecting the discharge side pump chamber and the discharge pipe via the first fluid pressure chamber;
A first throttle provided on the upstream side of the first fluid pressure chamber of the second flow path;
A second throttle provided on the downstream side of the first fluid pressure chamber of the second flow path;
A variable displacement vane pump comprising a third flow path connecting the second fluid pressure chamber and the discharge pipe. The variable displacement vane pump according to claim 14,
The variable displacement vane pump further comprising a variable control mechanism that variably controls the flow passage area of the second throttle. The variable displacement vane pump according to claim 15,
The variable displacement vane pump, wherein the variable control mechanism is a solenoid valve. The variable displacement vane pump according to claim 16,
The variable displacement vane pump, wherein the solenoid valve is provided so that a flow passage area of the second throttle is minimized when in a non-energized state. The variable displacement vane pump according to claim 16,
The variable displacement vane pump, wherein the solenoid valve is provided so that a flow passage area of the second throttle is maximized in a non-energized state. The variable displacement vane pump according to claim 16,
A variable displacement vane pump, further comprising: a controller that calculates an energization amount to the solenoid valve based on an input signal from the outside and energizes the solenoid valve with the calculated amount of current. The variable displacement vane pump according to claim 19,
A variable displacement vane pump, further comprising an emergency control device that minimizes the flow area of the second throttle when an energization amount to the solenoid valve or an abnormality of the control device is detected. The variable displacement vane pump according to claim 19,
A variable displacement vane pump, further comprising: an emergency control device that maximizes a flow passage area of the second throttle when an energization amount to the solenoid valve or an abnormality of the control device is detected. The variable displacement vane pump according to claim 14,
A variable displacement vane pump, further comprising a variable control mechanism that variably controls the flow path area of the orifice. The variable displacement vane pump according to claim 14,
The variable displacement vane pump further comprising a variable control mechanism that variably controls the flow path area of the first throttle. The variable displacement vane pump according to claim 14,
A third aperture provided in the third flow path;
A pressure relief valve provided in the third flow path so as to be positioned between the second fluid pressure chamber and the third throttle and discharging the working fluid to the outside when the pressure in the passage reaches a set value or more. And a variable displacement vane pump.

The variable displacement vane pump according to claim 14,
2. The variable displacement vane pump according to claim 1, wherein the external device is a CVT. The variable displacement vane pump according to claim 14,
The variable capacity vane pump, wherein the external device is a power steering device. A rotor provided in the pump body and driven to rotate;
A plurality of vanes provided in the circumferential direction of the rotor so as to be capable of moving back and forth in the radial direction of the rotor;
A cam ring which is provided in the pump body so as to be eccentric with respect to the rotation axis of the rotor, and which includes the rotor and forms a plurality of pump chambers together with the rotor and the plurality of vanes;
A first fluid pressure chamber formed between the cam ring and the pump body, wherein the first fluid pressure chamber decreases as the eccentric amount of the cam ring increases;
A second fluid pressure chamber formed between the cam ring and the pump body and expanding as the amount of eccentricity of the cam ring increases;
A pump chamber included in the plurality of pump chambers, wherein the suction side pump chamber expands with the rotation of the rotor and sucks the working fluid; and
A pump chamber included in the plurality of pump chambers, wherein the discharge chamber is reduced with the rotation of the rotor and discharges the working fluid;
A discharge pipe for supplying the working fluid from the discharge-side pump chamber to an external device;
A first flow path connecting the discharge side pump chamber and the discharge pipe;
An orifice provided in the first flow path;
A second flow path connecting the discharge-side pump chamber and the discharge pipe via the second fluid pressure chamber;
A pressure adjusting section provided in the second flow path, for maintaining the pressure of the second fluid pressure chamber higher than the pressure downstream of the orifice and lower than the pressure upstream of the orifice;
A variable displacement vane pump comprising a third flow path connecting the discharge-side pump chamber and the first fluid pressure chamber. A rotor provided in the pump body and driven to rotate;
A plurality of vanes provided in the circumferential direction of the rotor so as to be capable of moving back and forth in the radial direction of the rotor;
A cam ring which is provided in the pump body so as to be eccentric with respect to the rotation axis of the rotor, and which includes the rotor and forms a plurality of pump chambers together with the rotor and the plurality of vanes;
A first fluid pressure chamber formed between the cam ring and the pump body, wherein the first fluid pressure chamber decreases as the eccentric amount of the cam ring increases;
A second fluid pressure chamber formed between the cam ring and the pump body and expanding as the amount of eccentricity of the cam ring increases;
A pump chamber included in the plurality of pump chambers, wherein the suction side pump chamber expands with the rotation of the rotor and sucks the working fluid; and
A pump chamber included in the plurality of pump chambers, wherein the discharge chamber is reduced with the rotation of the rotor and discharges the working fluid;
A discharge pipe for supplying the working fluid from the discharge-side pump chamber to an external device;
A first flow path connecting the discharge side pump chamber and the discharge pipe;
An orifice provided in the first flow path;
A second flow path connecting the discharge side pump chamber and the discharge pipe via the first fluid pressure chamber;
A pressure adjusting unit provided in the second flow path and configured to maintain the pressure of the first fluid pressure chamber higher than the pressure downstream of the orifice and lower than the pressure upstream of the orifice;
A variable displacement vane pump comprising a third flow path connecting the second fluid pressure chamber and the discharge pipe.

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