JP5371795B2 - Variable displacement vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement vane pump improving controllability of a discharge flow rate. <P>SOLUTION: The variable displacement vane pump 100 in which a discharge capacity of a pump chamber 9 changes by an eccentric amount of a cam ring 4 with respect to a rotor 2 being changed includes: a first fluid pressure chamber 31 and a second fluid pressure chamber 32 defined in a storage space on the outer periphery of the cam ring 4 and making the cam ring 4 eccentric with respect to the rotor 2 by differential pressure therebetween; a throttle part 28 applying resistance to a working fluid discharged from the pump chamber 9; a control valve 21 operating according to differential pressure of an anterior part and a posterior part the throttle part 28 and controlling pressure of the working fluid of the first fluid pressure chamber 31 and the second fluid pressure chamber 32 so that the eccentric amount of the cam ring 4 with respect to the rotor 2 becomes small accompanying an increase in the rotational speed of the rotor 2; and a discharge port 16 formed at a position not interfering with the cam ring 4 even when the cam ring 4 moves and leading the working fluid discharged from the pump chamber 9 to the upstream side of the throttle part 28. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a variable displacement vane pump used as a hydraulic pressure supply source in hydraulic equipment.

  Conventionally, variable displacement vane pumps that change the discharge flow rate of hydraulic oil by changing the amount of eccentricity of the cam ring with respect to the rotor are known.

  Patent Document 1 discloses a spool that moves in accordance with a differential pressure across a first fluid pressure chamber and a second fluid pressure chamber formed on the outer peripheral side of the cam ring and an orifice provided in a discharge passage in order to move the cam ring. Discloses a variable displacement vane pump comprising a control valve for controlling the fluid pressure supplied to the first and second fluid pressure chambers.

Japanese Patent Laid-Open No. 8-200239

  However, in the variable displacement vane pump described in Patent Document 1, the cam ring is configured to interfere with the discharge port formed on the side plate as the cam ring moves, so The opening area changes, and the way (flow direction) of the hydraulic oil flowing from the discharge port into the discharge passage changes. As a result, the way in which the hydraulic oil flows into the orifice provided in the discharge passage also changes, and the differential pressure across the orifice fluctuates in accordance with the inflow state of the hydraulic oil. Therefore, the operation of the control valve also fluctuates, and there is a problem that the discharge flow rate of the hydraulic oil discharged from the vane pump during the cam ring movement deviates from a desired value.

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a variable displacement vane pump capable of improving the controllability of the discharge flow rate.

The present invention relates to a rotor coupled to a drive shaft , a plurality of vanes provided so as to be capable of reciprocating in the radial direction with respect to the rotor, and a cam on the inner periphery as the rotor is accommodated and rotated A cam ring that slides on the surface of the vane and is eccentric with respect to the center of the rotor, and a pump chamber defined between the rotor and the cam ring, the cam ring for the rotor In the variable displacement vane pump in which the discharge capacity of the pump chamber changes as the amount of eccentricity changes, the cam ring is defined in the housing space on the outer periphery of the cam ring, and the cam ring is eccentric with respect to the rotor due to a pressure difference between them. A first fluid pressure chamber and a second fluid pressure chamber, a throttle portion for imparting resistance to the working fluid discharged from the pump chamber, and a fluid pressure according to a differential pressure across the throttle portion. A control valve for controlling the pressure of the working fluid in the first fluid pressure chamber and the second fluid pressure chamber so that the eccentric amount of the cam ring with respect to the rotor decreases with an increase in the rotational speed of the rotor; A discharge port that is formed at a position that does not interfere with the cam ring even if the cam ring moves, and that guides the working fluid discharged from the pump chamber to the upstream side of the throttle portion, and the discharge port includes the cam ring and Provided on a side plate arranged to contact one side of the rotor, formed in an arc shape around the drive shaft and formed so that the opening width becomes narrower in the rotation direction of the drive shaft It is characterized by that.

According to the present invention, since the discharge port of the vane pump is formed so as not to interfere with the cam ring, the opening area of the discharge port does not change even if the cam ring moves. Therefore, there is no change in the differential pressure across the throttle due to the change in the opening area of the discharge port , the control valve can be controlled accurately, and the discharge flow rate of hydraulic oil can be set to a desired value even during cam ring movement. Can be adjusted. Thereby, the controllability of the discharge flow rate of the hydraulic oil in the vane pump can be improved.

It is sectional drawing which shows a cross section perpendicular | vertical to the drive shaft in the variable displacement vane pump in this invention. It is sectional drawing which shows a cross section parallel to the drive shaft in a variable displacement vane pump. It is a figure which shows the side plate of a variable displacement type vane pump. It is a hydraulic circuit diagram when the rotational speed of the rotor is a low rotational speed. It is a hydraulic circuit diagram when the rotational speed of a rotor is high rotational speed. It is a figure which shows the side plate of the conventional variable displacement vane pump. It is a figure explaining the effective orifice diameter of the orifice of the conventional variable displacement vane pump. It is a figure which shows the rotor rotational speed-discharge flow rate characteristic of the variable capacity type vane pump in this invention, and the conventional variable capacity type vane pump.

  Embodiments of the present invention will be described below with reference to the drawings.

  A variable displacement vane pump 100 according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view showing a cross section perpendicular to the drive shaft 1 in the variable displacement vane pump 100. FIG. 2 is a cross-sectional view showing a cross section parallel to the drive shaft 1 in the variable displacement vane pump 100. FIG. 3A is a plan view of the side plate 6 of the vane pump 100. FIG. 3B is a plan view of the side plate 6 when the cam ring 4 is at a position where the discharge capacity is minimum, and FIG. 3C is a side plate 6 when the cam ring 4 is at a position where the discharge capacity is maximum. FIG.

  A variable displacement vane pump (hereinafter referred to as “vane pump”) 100 is used as a hydraulic supply source for hydraulic equipment mounted on a vehicle, such as a power steering device or a continuously variable transmission.

  As shown in FIGS. 1 and 2, the vane pump 100 includes a drive shaft 1 to which power from an engine (not shown) is transmitted, a rotor 2 that is coaxially fixed to the drive shaft 1, and a diameter with respect to the rotor 2. A plurality of vanes 3 provided so as to be capable of reciprocating in a direction, and a cam ring 4 that is capable of eccentrically moving with respect to the center of the rotor 2 while the tip of the vane 3 slides on the inner circumferential cam surface 4A as the rotor 2 rotates. With.

  The drive shaft 1 is rotatably supported by the pump body 10 and a pump cover 5 disposed on the side of the pump body 10. In FIG. 1, the drive shaft 1 rotates counterclockwise.

  The pump body 10 is formed with an accommodation recess 10 </ b> A for accommodating the cam ring 4. A disc-shaped side plate 6 that abuts against one side of the rotor 2 and the cam ring 4 is disposed on the bottom surface 10B of the housing recess 10A. The opening of the accommodating recess 10 </ b> A is sealed by the pump cover 5 via a disk-shaped plate member 7 that contacts the rotor 2 and the other side of the cam ring 4.

  The pump cover 5 is fastened to the pump body 10 via bolts 8.

  In the vane pump 100, the side plate 6 and the plate member 7 are arranged with both side surfaces of the rotor 2 and the cam ring 4 being sandwiched, so that the pump chamber 9 partitioned by each vane 3 is provided between the rotor 2 and the cam ring 4. Defined.

  The cam ring 4 accommodated in the accommodating recess 10 </ b> A is an annular member, and the suction region that expands the volume of the pump chamber 9 as the rotor 2 rotates, and the volume of the pump chamber 9 as the rotor 2 rotates. And a discharge region that contracts. The pump chamber 9 sucks the working oil (working fluid) in the suction area and discharges the working oil in the discharge area. In FIG. 1, the suction area is above the horizontal line passing through the center of the cam ring 4, and the discharge area is below the horizontal line.

  An annular adapter ring 11 is fitted on the inner peripheral surface of the accommodating recess 10 </ b> A of the pump body 10 so as to surround the cam ring 4. Both side surfaces of the adapter ring 11 are sandwiched between the side plate 6 and the plate member 7. On the inner peripheral surface of the adapter ring 11, support pins 13 extending in parallel with the drive shaft 1 and having both side portions inserted into the side plate 6 and the plate member 7 are supported. A cam ring 4 is also supported on the support pin 13, and the cam ring 4 swings around the support pin 13 inside the adapter ring 11.

  As shown in FIG. 1, a groove 11 </ b> A extending in parallel with the drive shaft 1 is formed on the inner peripheral surface of the adapter ring 11 at a point symmetric with respect to the support pin 13 with respect to the center of the adapter ring 11. In the groove 11 </ b> A, a seal member 14 with which the outer peripheral surface of the cam ring 4 comes into sliding contact when the cam ring 4 moves is provided.

  A first fluid pressure chamber 31 and a second fluid pressure chamber 32 are defined by the support pin 13 and the seal member 14 between the outer peripheral surface of the cam ring 4 and the inner peripheral surface of the adapter ring 11. The cam ring 4 rotates around the support pin 13 as a fulcrum while being in sliding contact with the seal member 14 based on the pressure difference between the hydraulic oil pressure in the first fluid pressure chamber 31 and the hydraulic oil pressure in the second fluid pressure chamber 32. Move.

  As the cam ring 4 rotates in the adapter ring 11 in this manner, the eccentric amount of the cam ring 4 with respect to the rotor 2 changes, and the discharge capacity of the pump chamber 9 changes. When the pressure of the hydraulic oil in the first fluid pressure chamber 31 is higher than the pressure of the hydraulic oil in the second fluid pressure chamber 32, the eccentric amount of the cam ring 4 with respect to the rotor 2 is reduced (right side in FIG. 1). In the direction) the cam ring 4 rotates and the discharge capacity of the pump chamber 9 decreases. On the other hand, when the pressure of the hydraulic oil in the second fluid pressure chamber 32 is larger than the pressure of the hydraulic oil in the first fluid pressure chamber 31, the eccentric amount of the cam ring 4 with respect to the rotor 2 is increased. The cam ring 4 rotates (to the left in FIG. 1), and the discharge capacity of the pump chamber 9 increases.

  On the inner peripheral surface of the adapter ring 11 on the second fluid pressure chamber 32 side, a bulging portion 12 that restricts the movement of the cam ring 4 in a direction in which the amount of eccentricity with respect to the rotor 2 decreases is formed. The bulging portion 12 ensures the minimum eccentricity of the cam ring 4 with respect to the rotor 2 so that the eccentric amount of the cam ring 4 with respect to the rotor 2 does not become zero, that is, even when the outer peripheral surface of the cam ring 4 is in contact with the bulging portion 12. The pump chamber 9 is formed in such a shape that the hydraulic oil can be discharged. In this way, the bulging portion 12 ensures the minimum discharge capacity of the pump chamber 9.

  As shown in FIG. 2, the plate member 7 disposed between the pump cover 5 and the rotor 2 includes a suction port 15 that opens in an arc shape with respect to the suction region of the pump chamber 9. The suction port 15 is formed so as to communicate with a suction passage 17 formed in the pump cover 5, and guides hydraulic oil flowing through the suction passage 17 to the pump chamber 9 on the suction region side.

  As shown in FIGS. 2 and 3A, the side plate 6 disposed between the bottom surface 10B of the housing recess 10A and the rotor 2 includes a discharge port 16 that opens to the discharge region of the pump chamber 9, and a plate member. 7 and an arcuate suction groove portion 20 provided at a position corresponding to the suction port 15. The discharge port 16 is formed in an arc shape around the drive shaft 1 so as to communicate with the high-pressure chamber 18 formed in the pump body 10. The discharge port 16 guides hydraulic oil discharged from the pump chamber 9 on the discharge region side to the high pressure chamber 18.

  As shown in FIGS. 3B and 3C, the discharge port 16 is formed so that the cam ring 4 does not interfere with the discharge port 16 in the process of movement of the cam ring 4. That is, since the discharge port 16 is formed so that the opening width gradually decreases in the rotation direction of the drive shaft 1 indicated by the arrow, the discharge capacity in a state where the cam ring 4 is in contact with the bulging portion 12. Even if it moves from the minimum position (FIG. 3B) to the discharge capacity maximum position (FIG. 3C) in contact with the left side of the adapter ring 11, the opening of the discharge port 16 is largely blocked. There is no.

  Thus, in the vane pump 100 of this embodiment, even if the cam ring 4 moves, the opening area of the discharge port 16 does not change.

  As shown in FIGS. 1 and 2, the high-pressure chamber 18 that communicates with the discharge port 16 is defined by a groove 10 </ b> C formed in an annular shape on the bottom surface 10 </ b> B of the housing recess 10 </ b> A being closed by the side plate 6. . The high-pressure chamber 18 is connected to a discharge passage 19 that is formed in the pump body 10 and guides hydraulic oil to hydraulic equipment. The high pressure chamber 18 communicates with the second fluid pressure chamber 32 through a throttle passage 36 formed in the side plate 6. Accordingly, the hydraulic oil in the high pressure chamber 18 is always guided to the second fluid pressure chamber 32. Since the side plate 6 is pressed against the rotor 2 and the vane 3 by the pressure of the hydraulic oil in the high pressure chamber 18, the clearance of the side plate 6 with respect to the rotor 2 and the vane 3 is reduced, and leakage of the hydraulic oil is suppressed.

  The vane pump 100 includes a control valve 21 that controls the pressure of hydraulic fluid in the first fluid pressure chamber 31 and the second fluid pressure chamber 32.

  The control valve 21 will be described with reference to FIGS. 1 and 4. FIG. 4 is a hydraulic circuit diagram when the rotational speed of the rotor 2 is a low rotational speed.

  As shown in FIG. 1, the control valve 21 is housed in a valve housing hole 29 formed in the pump body 10 in a direction orthogonal to the axial direction of the drive shaft 1.

  The control valve 21 includes a spool 22 slidably inserted into the valve housing hole 29, a first spool chamber 24 defined between one end of the spool 22 and the bottom of the valve housing hole 29, A second spool chamber 25 defined between the other end and the plug 23 that seals the valve accommodating hole 29, and a spool that is accommodated in the second spool chamber 25 and expands the volume of the second spool chamber 25. And a return spring 26 for urging 22.

  The spool 22 is a rod-shaped member, and includes a first land portion 22A and a second land portion 22B that slide along the inner peripheral surface of the valve housing hole 29, and a first land portion 22A and a second land portion 22B. And an annular groove 22C formed therebetween.

  As shown in FIG. 4, the control valve 21 is configured to operate by a differential pressure across the orifice (throttle portion) 28 interposed in the discharge passage 19. The hydraulic oil upstream of the orifice 28 is guided to the first spool chamber 24 of the control valve 21 via the first pressure guiding passage 37, and the hydraulic oil downstream of the orifice 28 is secondly supplied to the second spool chamber 25. It is guided through the pressure guiding passage 38. In this way, a part of the hydraulic oil in the high pressure chamber 18 is directly guided to the first spool chamber 24 through the first pressure guide passage 37 without passing through the orifice 28, and through the orifice 28 and the second pressure guide passage 38. To the second spool chamber 25.

  In addition, the control valve 21 communicates with the first fluid pressure passage 33 and the second fluid pressure passage 34 that communicate with the first fluid pressure chamber 31 and the second fluid pressure chamber 32, respectively, with the annular groove 22 </ b> C and with the suction passage 17. And a drain passage 35 communicating with each other.

  The spool 22 of the control valve 21 stops at a position where the load due to the pressure of the hydraulic oil guided to the first spool chamber 24 and the second spool chamber 25 and the urging force of the return spring 26 are balanced. Depending on the stop position of the spool 22, the first fluid pressure passage 33 and the second fluid pressure passage 34 are opened and closed by the first land portion 22A and the second land portion 22B, respectively, and the first fluid pressure chamber 31 and the second fluid pressure chamber 32 are opened. The hydraulic oil is supplied and discharged.

  The operation of the vane pump 100 will be described with reference to FIGS. FIG. 4 is a hydraulic circuit diagram when the rotational speed of the rotor 2 is low, and FIG. 5 is a hydraulic circuit diagram when the rotational speed of the rotor 2 is high.

  When the engine power is transmitted to the drive shaft 1 and the rotor 2 rotates, the pump chamber 9 that expands with the rotation of the rotor 2 sucks hydraulic oil from the suction passage 17 through the suction port 15, and with the rotation of the rotor 2. The pump chamber 9 that contracts in this way discharges hydraulic oil to the high-pressure chamber 18 through the discharge port 16. The hydraulic oil discharged to the high pressure chamber 18 is supplied to the hydraulic equipment through the discharge passage 19.

  When the hydraulic oil passes through the discharge passage 19, a pressure difference is generated before and after the orifice 28 interposed in the discharge passage 19. The pressure of the hydraulic oil upstream of the orifice 28 is guided to the first spool chamber 24 of the control valve 21 via the first pressure guide passage 37, and the pressure of the hydraulic oil downstream of the orifice 28 is sent to the second pressure guide passage 38. Through the second spool chamber 25 of the control valve 21. The spool 22 of the control valve 21 moves to a position where the load due to the pressure difference between the hydraulic oil guided to the first spool chamber 24 and the second spool chamber 25 and the urging force of the return spring 26 are balanced.

  As shown in FIG. 4, when the rotational speed of the rotor 2 is low, such as when the pump is started, the differential pressure across the orifice 28 is small. Therefore, the total load of the load due to the pressure of the second spool chamber 25 and the urging force of the return spring 26 becomes larger than the load due to the pressure of the first spool chamber 24, and the spool 22 moves due to the urging force of the return spring 26. The tip of 22 is in contact with the bottom of the valve housing hole 29.

  In this case, the first fluid pressure chamber 31 is disconnected from the high pressure chamber 18 by the first land portion 22A of the spool 22, and the drain passage 35 is connected via the communication passage 22D formed in the first land portion 22A. Communicate with. The second fluid pressure chamber 32 is blocked from communicating with the drain passage 35 by the second land portion 22 </ b> B of the spool 22. The hydraulic fluid in the first fluid pressure chamber 31 is discharged to the drain passage 35 via the communication passage 22D and the annular groove 22C, and the hydraulic fluid in the high pressure chamber 18 is guided to the second fluid pressure chamber 32 through the throttle passage 36. The cam ring 4 is at a position where the amount of eccentricity with respect to the rotor 2 is maximized by the pressure of the hydraulic oil in the second fluid pressure chamber 32.

  In this way, the vane pump 100 discharges the hydraulic oil with the maximum discharge capacity, and the flow rate of the hydraulic oil discharged from the vane pump 100 is approximately proportional to the rotational speed of the rotor 2. Thereby, even when the rotational speed of the rotor 2 is low, it is possible to supply a sufficient amount of hydraulic oil to the hydraulic equipment.

  In contrast, as the rotational speed of the rotor 2 increases, the differential pressure across the orifice 28 increases. When the load due to the pressure in the first spool chamber 24 becomes larger than the total load of the load due to the pressure in the second spool chamber 25 and the biasing force of the return spring 26, the spool 22 is attached to the return spring 26 as shown in FIG. Move against the power.

  In this case, the first fluid pressure chamber 31 communicates with the high pressure chamber 18 via the first fluid pressure passage 33, the first spool chamber 24, and the first pressure guide passage 37. The second fluid pressure chamber 32 communicates with the drain passage 35 via the second fluid pressure passage 34 and the annular groove 22C. The communication between the second fluid pressure passage 34 and the annular groove 22 </ b> C is performed through a notch 22 </ b> E formed in the second land portion 22 </ b> B of the spool 22, and the drain passage for the second fluid pressure chamber 32 according to the movement amount of the spool 22. The opening area of 35 increases or decreases.

  When the first fluid pressure chamber 31 communicates with the high pressure chamber 18 and the second fluid pressure chamber 32 communicates with the drain passage 35 as described above, the hydraulic fluid in the high pressure chamber 18 is supplied to the first fluid pressure chamber 31. The hydraulic fluid in the second fluid pressure chamber 32 is discharged to the drain passage 35. As a result, the cam ring 4 moves in a direction in which the amount of eccentricity with respect to the rotor 2 decreases according to the pressure difference between the first fluid pressure chamber 31 and the second fluid pressure chamber 32. As the amount of eccentricity of the cam ring 4 with respect to the rotor 2 becomes smaller, the outer peripheral surface of the cam ring 4 comes into contact with the bulging portion 12 on the inner peripheral surface of the adapter ring 11 and the movement of the cam ring 4 is restricted. As a result, the amount of eccentricity of the cam ring 4 with respect to the rotor 2 is minimized, and the pump chamber 9 has a minimum discharge capacity.

  In this way, the vane pump 100 is controlled to a pump discharge capacity corresponding to the differential pressure across the orifice 28 of the discharge passage 19, and the discharge flow rate of the hydraulic oil is adjusted to be substantially constant even if the rotational speed of the rotor 2 increases. . Thereby, the hydraulic fluid supplied with respect to hydraulic equipment at the time of driving | running | working of a vehicle is adjusted moderately.

  Next, the effects of the vane pump 100 of the present embodiment will be described with reference to FIGS. 6 to 8 while comparing with the conventional vane pump 200.

  6A is a plan view of the side plate 206 when the cam ring 204 of the vane pump 200 is at a position where the discharge capacity is minimum, and FIG. 6B is a position where the cam ring 204 of the vane pump 200 is at the position where discharge capacity is maximum. It is a top view of the side plate 206 in a certain case. FIGS. 7A and 7B are diagrams illustrating the effective orifice diameter of the orifice 228 of the vane pump 200 when the opening area of the discharge port 216 changes. FIG. 8 is a diagram illustrating the rotor rotational speed-discharge flow rate characteristics of the vane pumps 100 and 200.

Conventional vane pump 200 includes, as shown in FIG. 6 (A) and 6 (B), in accordance with the movement of the cam ring 20 4, the cam ring 20 4 so as to interfere with the discharge port 216 formed in the side plate 206 It is configured. That is, in the vane pump 200, the opening area of the discharge port 216 increases as the cam ring 204 moves from the maximum discharge capacity position (FIG. 6B) toward the minimum discharge capacity position (FIG. 6A). It is configured.

  When the opening area of the discharge port 216 increases with the movement of the cam ring 204, the manner in which hydraulic oil flows into the orifice 228 provided in the discharge passage 219 changes, that is, as shown by the arrow F1 in FIG. A flow in which the straight component is dominant changes to a flow in which the curved component as indicated by an arrow F2 in FIG. 7B is dominant. As shown in FIG. 7B, when the hydraulic oil flows into the orifice 228 so as to go around from the inlet portion of the orifice 228, the apparent orifice diameter in the orifice 228 is compared with the case of FIG. 7A. (Hereinafter referred to as “effective orifice diameter”) decreases, and the differential pressure across the orifice 228 increases. As a result, the amount of movement of the spool of the control valve becomes larger than usual, and the amount of movement of the cam ring 204 also increases. As shown by the broken line in FIG. It will be lower than (solid line).

  As described above, the conventional vane pump 200 has a problem that the controllability of the discharge flow rate of the hydraulic oil is deteriorated by changing the opening area of the discharge port 216 according to the position of the cam ring 204.

  However, the vane pump 100 of the present embodiment is configured so that the cam ring 4 does not interfere with the discharge port 16 during the movement of the cam ring 4 as shown in FIGS. 3B and 3C. Even when the cam ring 4 moves from the maximum discharge capacity position (FIG. 3C) to the minimum discharge capacity position (FIG. 3B), the opening area of the discharge port 16 does not change. Therefore, even if the cam ring 4 moves, the effective orifice diameter in the orifice 28 does not change, so that the spool 22 does not move too much during the movement of the cam ring 4. Therefore, the discharge flow rate of the hydraulic oil discharged from the vane pump 100 is adjusted to a desired value as shown by the solid line in FIG.

  As described above, the vane pump 100 of the present embodiment can obtain the following effects.

  In the vane pump 100, since the discharge port 16 is formed on the side plate 6 so as not to interfere with the cam ring 4 in the process of movement of the cam ring 4, the opening area of the discharge port 16 may change even if the cam ring 4 moves. Absent. Accordingly, there is no change in the effective orifice diameter of the orifice 28 due to the change in the opening area of the discharge port 16, the spool 22 of the control valve 21 can be accurately controlled, and the hydraulic oil discharge flow rate even when the cam ring 4 moves. Can be adjusted to a desired value. Thereby, the controllability of the discharge flow rate of the hydraulic oil in the vane pump 100 can be improved.

  Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The orifice 28 formed in the discharge passage 19 may be either a variable type or a fixed type as long as it provides resistance to the flow of hydraulic oil discharged from the pump chamber 9.

  The variable displacement vane pump of the present invention can be applied to a hydraulic pressure supply source of hydraulic equipment such as a power steering device and a continuously variable transmission.

100 variable displacement vane pump 1 drive shaft 2 rotor 3 vane 4 cam ring 6 side plate 9 pump chamber 11 adapter ring 13 support pin 15 suction port 16 discharge port 17 suction passage 18 high pressure chamber 19 discharge passage 21 control valve 22 spool 24 first spool Chamber 25 Second spool chamber 26 Return spring 28 Orifice 31 First fluid pressure chamber 32 Second fluid pressure chamber 33 First fluid pressure passage 34 Second fluid pressure passage 35 Drain passage 36 Throttle passage 37 First pressure guide passage 38 Second Induction passage

Claims (2)

A rotor coupled to the drive shaft;
A plurality of vanes provided so as to be capable of reciprocating in the radial direction with respect to the rotor;
A cam ring that houses the rotor, and that the tip of the vane slides on the inner cam surface as the rotor rotates, and is eccentric with respect to the center of the rotor;
A pump chamber defined between the rotor and the cam ring,
In the variable displacement vane pump in which the discharge capacity of the pump chamber is changed by changing the amount of eccentricity of the cam ring with respect to the rotor,
A first fluid pressure chamber and a second fluid pressure chamber which are defined in a housing space on an outer periphery of the cam ring and decenter the cam ring with respect to the rotor by a pressure difference between each other;
A throttle that provides resistance to the working fluid discharged from the pump chamber;
The first fluid pressure chamber and the second fluid pressure chamber operate in accordance with the differential pressure across the throttle portion so that the amount of eccentricity of the cam ring with respect to the rotor decreases as the rotational speed of the rotor increases. A control valve for controlling the pressure of the working fluid;
A discharge port that is formed at a position that does not interfere with the cam ring even if the cam ring moves, and that guides the working fluid discharged from the pump chamber to the upstream side of the throttle portion ,
The discharge port is provided on a side plate disposed so as to abut one side of the cam ring and the rotor, and is formed in an arc shape around the drive shaft and toward the rotation direction of the drive shaft. Formed so that the opening width is narrow,
This is a variable displacement vane pump.   2. The variable displacement vane pump according to claim 1, wherein the discharge port is formed such that an opening area does not change when the cam ring moves from a maximum discharge capacity position to a minimum discharge capacity position. 3.

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