WO2018147081A1 - Variable displacement pump - Google Patents

Abstract

In this variable displacement pump 1, first and second intake areas, which are a pair of areas in which the volume of each of a plurality of pump chambers 16 increases following rotation of a rotor 7, are disposed in symmetrical positions with respect to a rotational axis O. Furthermore, first and second discharge areas, which are a pair of areas in which the volume of each of the plurality of pump chambers 16 decreases following rotation of the rotor 7, are disposed in symmetrical positions with respect to the rotational axis O. The ratio of the amount of increase in the volume of the plurality of pump chambers 16 in the first and second intake areas, to the amount of decrease in the volume of the plurality of pump chambers 16 in the first and second discharge areas, is changed by rotating a cam ring 8 in a direction around the rotational axis O with respect to a housing 2.

Description

Variable displacement pump

The present invention relates to a variable displacement pump.

Patent Document 1 discloses a variable displacement pump having a rotor that is rotationally driven by a drive shaft, a plurality of vanes provided on the outer periphery of the rotor, and a cam ring that houses the rotor. In this variable displacement pump, the capacity of each pump chamber is variable by swinging the cam ring.

JP 2016-156367 A

Generally, in a variable displacement pump, the suction area and the discharge area of the pump are arranged at symmetrical positions with respect to the drive shaft. For this reason, the variable displacement pump has a problem that the pressure acting on the drive shaft is unbalanced, and the pulsation and vibration of the pump are large.
One of the objects of the present invention is to provide a variable displacement pump capable of suppressing pulsation and vibration.

In the variable displacement pump according to an embodiment of the present invention, the first suction region and the second suction region, which are a pair of regions in which the volumes of the plurality of pump chambers increase as the rotor rotates, rotate the drive shaft. A first discharge region and a second discharge region, which are a pair of regions that are disposed in a symmetric position with respect to the axis and in which the respective volumes of the plurality of pump chambers are reduced, are disposed in a symmetric position with respect to the rotation axis, and are disposed in the housing. In contrast, by rotating the cam ring in the direction around the rotation axis, the amount of increase in the volume of the plurality of pump chambers in the first suction region and the second suction region and the volume of the plurality of pump chambers in the first discharge region and the second discharge region are reduced. Change the ratio with the amount of decrease.

Therefore, according to a preferred aspect of the present invention, the pressure acting on the drive shaft is balanced, so that pulsation and vibration can be suppressed.

1 is a schematic diagram of a variable displacement pump 1 according to Embodiment 1. FIG. 1 is an axial sectional view of a variable displacement pump 1 according to Embodiment 1. FIG. It is explanatory drawing which shows the discharge amount at the time of cam non-rotation. It is explanatory drawing which shows the discharge amount at the time of cam rotation. FIG. 6 is a schematic diagram of a main part of a variable displacement pump 51 according to a second embodiment. 6 is a schematic diagram of a variable displacement pump 53 of Embodiment 3. FIG. FIG. 6 is a schematic diagram of a main part of a variable displacement pump 55 according to a fourth embodiment.

Embodiment 1
A configuration of the variable displacement pump 1 of the first embodiment will be described.
FIG. 1 is a schematic diagram of a variable displacement pump 1 according to the first embodiment. FIG. 2 is an axial sectional view of the variable displacement pump 1 according to the first embodiment.
The variable displacement pump 1 is a pump device applied to a power steering device for a vehicle. The variable displacement pump 1 functions as a fluid pressure generating source that supplies power steering oil (hereinafter referred to as hydraulic fluid) to the power steering device. The power steering apparatus has a power cylinder provided in a steering gear box. The variable displacement pump 1 is driven by an internal combustion engine as a prime mover, sucks hydraulic fluid from a reservoir tank 31, and discharges the hydraulic fluid to a power cylinder.

The variable displacement pump 1 has a housing 2. The housing 2 is formed by abutting the front housing 3 and the rear housing 4 together. The housing 2 has a pump element accommodating portion 5 therein. The pump element accommodating portion 5 is a substantially cylindrical space, and the pump element 6 is accommodated therein. The pump element 6 has a rotor 7 and a cam ring 8. The pump element accommodating portion 5 includes an adapter ring portion 9 and a pressure plate 10. The rotor 7 has a drive shaft 11 passing through the center. The rotor 7 and the drive shaft 11 are serrated. The drive shaft 11 is rotationally driven by the crankshaft of the engine. Both ends of the drive shaft 11 are supported by the bearings 12 and 13 and rotate around the rotation axis O (hereinafter also simply referred to as the axis periphery). The bearing 12 is a ball bearing and is disposed in the front housing 3. The bearing 13 is a needle bearing and is disposed in the rear housing 4. An oil seal 14 is disposed in the front housing 3 adjacent to the bearing 12. The oil seal 14 has a function of preventing hydraulic fluid from leaking from the pump element housing 5 side to the bearing 12 side. The rotor 7 has, on its outer periphery, a plurality of slots 7a cut out along a radial direction (hereinafter also simply referred to as a radial direction) in the rotation axis O. The slots 7a are arranged at an equal pitch in the circumferential direction of the rotation axis O (hereinafter also simply referred to as the circumferential direction). A back pressure chamber 7b is formed on the inner peripheral side of each slot 7a. The hydraulic fluid pressurized in the pump chamber 16 is introduced into each back pressure chamber 7b. In each slot 7a, a substantially flat vane 15 is accommodated so as to be able to protrude and retract in the radial direction of the rotor 7. Each vane 15 is pressed against the inner cam surface 8a of the cam ring 8 by the pressure of the hydraulic fluid introduced into the back pressure chamber 7b.

The cam ring 8 is formed in an annular shape surrounding the rotor 7. The cam ring 8 has a substantially elliptical inner cam surface 8a. A plurality of pump chambers 16 are formed by each vane 15 partitioning the annular space between the cam ring 8 and the rotor 7 in the circumferential direction. The adapter ring portion 9 is formed in an annular shape surrounding the cam ring 8. The adapter ring portion 9 holds the cam ring 8 so as to be rotatable around the axis. The adapter ring portion 9 is restricted from rotating around the axis with respect to the housing 2 by a rotation prevention pin 17. On the inner periphery of the adapter ring portion 9, a protruding portion 18 that protrudes radially inward is formed. On the other hand, a notch groove 20 is formed on the outer periphery of the cam ring 8 over a predetermined angular range in the circumferential direction. The protrusion 18 protrudes into the notch groove 20. The protrusion 18 has a cam seal (first seal member) 19 at its tip. The cam seal 19 seals between the tip of the protrusion 18 and the notch groove 20.

The cam ring 8 can rotate within a predetermined angle range by the relative movement of the protruding portion 18 in the circumferential direction within the cutout groove 20. In the circumferential direction of the cam ring 8, a portion where the notch groove 20 is formed is a small diameter portion 21. Further, in the circumferential direction of the cam ring 8, an end portion including one side wall of the notch groove 20 is a first large diameter portion 22, and an end portion including the other side wall is a second large diameter portion 23. The outer diameter of the small diameter portion 21 is smaller than the first large diameter portion 22 and the second large diameter portion 23 by the notch groove 20. The cam ring 8 is connected to the adapter ring portion 9 in a circumferential direction from a state where the projecting portion 18 and the first large diameter portion 22 abut to a state where the projecting portion 18 and the second large diameter portion 23 abut. Relative rotation is possible. The first large diameter portion 22 has a cam seal (second seal member) 24 on its outer periphery. The cam seal 24 seals between the inner peripheral surface of the adapter ring portion 9 and the first large diameter portion 22. A step portion 22 a is formed at the end of the first large diameter portion 22. The stepped portion 22a is thinner than the other portions of the cam ring 8 (the dimension along the rotational axis O (hereinafter, also simply referred to as the axial direction) is small).

The space between the inner peripheral surface of the adapter ring portion 9 and the outer peripheral surface of the small diameter portion 21 and the region between the protruding portion 18 and the first large diameter portion 22 is a main cam control chamber 25. On the other hand, a space between the inner peripheral surface of the adapter ring portion 9 and the outer peripheral surface of the small diameter portion 21, and a region between the protruding portion 18 and the second large diameter portion 23 is a sub cam control chamber 26. High pressure or low pressure hydraulic fluid is selectively supplied to the main cam control chamber 25 by a spool type control valve 29 that operates by a differential pressure across the metering orifice 28 formed in the discharge passage 27. The pair of cam seals 19 and 24 prevent the hydraulic fluid in the main cam control chamber 25 from leaking. Therefore, it can be said that the main cam control chamber 25 is a space between the pair of cam seals 19 and 24. The discharge passage 27 is formed in the rear housing 4 and discharges the hydraulic fluid pressurized in each pump chamber 16 to the outside. The control valve 29 is accommodated in the housing 2. On the other hand, hydraulic fluid is always supplied from the reservoir tank 31 to the auxiliary cam control chamber 26 via the suction passage 30 formed in the housing 2. The reservoir tank 31 stores the hydraulic fluid in an open state.

The tip of each vane 15 of the rotor 7 that is driven to rotate inside the inner cam surface 8a is in sliding contact with the cam ring 8, so that the rotation direction of the rotor 7 (counterclockwise direction in FIG. 1) is caused by so-called rotation. Rotation behavior in the same direction is given. That is, when the rotor 7 rotates, the rotational friction of each vane 15 always acts on the cam ring 8. Due to this rotational friction, when the main cam control chamber 25 is in a low pressure state, the cam ring 8 is in a state where the first large-diameter portion 22 constituting the main cam control chamber 25 and the protruding portion 18 are in contact with each other, and the variable displacement pump 1 maintains the maximum discharge rate. Further, when the amount of discharge increases as the rotational speed of the drive shaft 11 increases and the hydraulic fluid supplied to the main cam control chamber 25 through the control valve 29 becomes high pressure, the cam ring 8 is connected to each vane 15 in accordance with this pressure increase. The rotor 7 rotates in the opposite direction (the clockwise direction in FIG. 1) against the rotational friction of the rotor 7.

The pressure plate 10 is disposed in pressure contact with the front housing 3 side of the pump element 6. On the side opposite to the front housing 3 of the pump element 6, the end surface of the rear housing 4 is pressed as a side plate. Note that the pressure plate 10, the adapter ring portion 9, and the rear housing 4 are integrally assembled and fixed in a state of being positioned in the circumferential direction by an appropriate anti-rotation structure including the anti-rotation pin 17. A pressure chamber 32 is formed on the contact surface of the front housing 3 with the pressure plate 10. The hydraulic fluid pressurized in each pump chamber 16 is supplied to the pressure chamber 32. The pressure plate 10 is pressed against the rotor 7 by the hydraulic fluid supplied to the pressure chamber 32. The pressure plate 10 is formed with a first suction port 33, a second suction port 34, a first discharge port 35 and a second discharge port 36. Each port 33, 34, 35, 36 is formed in an arc shape extending in the circumferential direction, and penetrates the pressure plate 10 in the axial direction. When viewed from the direction of the rotation axis O, the first suction port 33 and the second suction port 34 have a point-symmetric (two-fold symmetry) shape with a point on the rotation axis O as a symmetry point. The first discharge port 35 and the second discharge port 36 are disposed at positions that are 90 ° out of phase with respect to the first suction port 33 and the second suction port 34. When viewed from the direction of the rotation axis O, the first discharge port 35 and the second discharge port 36 have a point-symmetric (two-fold symmetry) shape with a point on the rotation axis O as a symmetric point.

The first suction port 33 and the second suction port 34 have a capacity of each pump chamber 16 as the rotor 7 rotates in a state where the first large diameter portion 22 of the cam ring 8 is in contact with the protruding portion 18 of the adapter ring portion 9. Open to a pair of first and second suction areas where the gradually increases. The first suction area and the second suction area are set at symmetrical positions with respect to the rotation axis O. That is, when viewed from the direction of the rotation axis O, the first suction region and the second suction region have a point-symmetric (two-fold symmetry) shape with a point on the rotation axis O as a symmetric point. The first suction port 33 and the second suction port 34 are connected to suction passages 30 a and 30 b branched from the suction passage 30. On the other hand, the first discharge port 35 and the second discharge port 36 are connected to the pump chambers 16 as the rotor 7 rotates in a state where the first large diameter portion 22 of the cam ring 8 is in contact with the protruding portion 18 of the adapter ring portion 9. Open to a pair of first discharge area and second discharge area where the volume of the first discharge area gradually decreases. The first discharge region and the second discharge region are disposed at positions that are 90 ° out of phase with respect to the first suction region and the second suction region. The first discharge area and the second discharge area are set at symmetrical positions with respect to the rotation axis O. That is, when viewed from the direction of the rotation axis O, the first discharge area and the second discharge area have a point-symmetric (two-fold symmetry) shape with a point on the rotation axis O as a symmetric point. The first discharge port 35 and the second discharge port 36 are connected to the discharge passage 27 via discharge passages 39 and 40 formed in the housing 2.

The small-diameter portion 21 of the cam ring 8 overlaps the boundary between the second discharge region and the first suction region in the circumferential direction, and the boundary between the first suction region and the first discharge region and the first discharge region. It is provided at a position that does not overlap the boundary between the two suction areas and the second discharge area.
Here, one of the pump chambers 16 is between the first suction port 33 and the first discharge port 35 and communicates with both the first suction port 33 and the first discharge port 35. The area that does not exist is defined as the first confinement area. An area where one of the pump chambers 16 is between the second suction port 34 and the second discharge port 36 and does not communicate with either the second suction port 34 or the second discharge port 36. Is the second confinement region. At this time, the first suction port 33 is disposed adjacent to the first confinement region. The second suction port 34 is disposed adjacent to the second confinement region.

The hydraulic fluid flowing into the suction passage 30 from the reservoir tank 31 passes through the suction passage 30 and the suction passages 30a and 30b, and is sucked into the pump chambers 16 from the first suction port 33 and the second suction port 34. The hydraulic fluid introduced into each pump chamber 16 is sequentially compressed according to the movement of each vane 15, passes through the discharge passages 39 and 40 and the discharge passage 27 from the first discharge port 35 and the second discharge port 36, It is discharged to the outside.
A suction pressure introduction passage 41 is formed in the rear housing 4. One end side of the suction pressure introduction passage 41 is connected to the suction passage 30a. The other end side of the suction pressure introduction passage 41 is connected to the sub cam control chamber 26. The opening end 41 a of the suction pressure introduction passage 41 in the sub cam control chamber 26 is disposed at a position where the second large diameter portion 23 is not blocked by the second large diameter portion 23 even when the second large diameter portion 23 is in contact with the protruding portion 18.

The control valve 29 is disposed in the front housing 3. The control valve 29 has a valve hole 42, a spool 43 and a spring 44. The valve hole 42 extends in a direction orthogonal to the rotation axis O. In the housing 2, an upstream pressure introduction passage 45 connected to the valve hole 42 is formed. The upstream pressure introduction passage 45 is connected to the upstream pressure introduction passage 9 a formed in the adapter ring portion 9. The upstream pressure introduction passage 9 a passes through the adapter ring portion 9 in the radial direction and opens into the main cam control chamber 25. The spool 43 is a spool valve body having a substantially bottomed cylindrical shape. The spring 44 is a compression coil spring and urges the spool 43 toward one axial side (left side in FIG. 1). The valve hole 42 is partitioned into a high pressure chamber 46, an intermediate pressure chamber 47 and a low pressure chamber 48 by a spool 43. The high pressure chamber 46 is connected to the upstream side of the metering orifice 28 of the discharge passage 27. The intermediate pressure chamber 47 is connected to the downstream side of the metering orifice 28 of the discharge passage 27. The low pressure chamber 48 is arranged in the middle of the suction passage 30.

The spool 43 moves in the axial direction in accordance with the pressure difference between the intermediate pressure chamber 47 and the high pressure chamber 46. When the pressure difference between the intermediate pressure chamber 47 and the high pressure chamber 46 is less than a predetermined pressure difference, the spool 43 maintains a state where it abuts against the end surface 42a of the valve hole 42 by the urging force of the spring 44. At this time, the upstream pressure introduction passage 45 is in communication with the low pressure chamber 48, and the working fluid of the low pressure chamber 48 is introduced into the main cam control chamber 25. When the pressure difference between the intermediate pressure chamber 47 and the high pressure chamber 46 exceeds a predetermined pressure difference, the spool 43 moves to the other side in the axial direction (the right side in FIG. 1) against the urging force of the spring 44. At this time, the upstream pressure introduction passage 45 is in communication with the high pressure chamber 46, and the working fluid of the high pressure chamber 46 is introduced into the main cam control chamber 25. That is, the hydraulic fluid in the low pressure chamber 48 or the high pressure chamber 46 is selectively introduced into the main cam control chamber 25 according to the differential pressure across the metering orifice 28. On the other hand, hydraulic fluid is always introduced from the low pressure chamber 48 into the sub cam control chamber 26 regardless of the differential pressure across the metering orifice 28.
A relief valve 49 is formed inside the spool 43. The relief valve 49 performs a relief operation when the pressure in the intermediate pressure chamber 47, that is, the pressure of the hydraulic fluid supplied to the power steering device becomes more than necessary, and allows the intermediate pressure chamber 47 and the low pressure chamber 48 to communicate with each other. The working fluid is refluxed to the suction passage 30.

A bearing holding portion 9b is formed on the inner circumference of the adapter ring portion 9 over a predetermined angular range in the circumferential direction. The bearing holding portion 9b is a notch groove, and is disposed in a region between the pair of cam seals 19, 24 with respect to the rotation axis O, that is, at a position opposite to the main cam control chamber 25. A bearing 50 is accommodated in the bearing holding portion 9b. The bearing 50 is a needle bearing. The bearing 50 aims to reduce the positional deviation of the cam ring 8 and the friction during rotation, and supports a predetermined angular range on the outer periphery of the cam ring 8 so as to be rotatable about an axis. The circumferential width of the bearing 50 is set longer than the circumferential width of the main cam control chamber 25 when the main cam control chamber 25 has the maximum volume. The bearing 50 is located on the opposite side of the main cam control chamber 25 with respect to the rotation axis O regardless of the volume of the main cam control chamber 25.
The second suction port 34 has an extension 34a that extends radially outward. The extension portion 34a is connected to the bearing holding portion 9b, that is, the region between the cam ring 8 and the bearing 50.

Next, the operation of the variable displacement pump 1 of the first embodiment will be described.
The hydraulic fluid sucked into the pump chambers 16 from the first suction port 33 and the second suction port 34 is compressed in the pump chambers 16 as the rotor 7 rotates, and the first discharge port 35 and the second discharge port 36 side. Sent to. The hydraulic fluid discharged from the first discharge port 35 and the second discharge port 36 is discharged from the discharge passage 27 to the outside of the housing 2.
When the rotational speed of the drive shaft 11 is less than the predetermined rotational speed, the pressure loss of the metering orifice 28 is very small, so the pressure difference between the high pressure chamber 46 and the intermediate pressure chamber 47 is less than the predetermined pressure difference. Therefore, the spool 43 of the control valve 29 is maintained in contact with the end surface 42a by the urging force of the spring 44. Accordingly, low pressure hydraulic fluid is introduced into the main cam control chamber 25 from the suction passage 30 as in the case of the sub cam control chamber 26, and no pressure difference is generated between the main cam control chamber 25 and the sub cam control chamber 26. Therefore, the cam ring 8 maintains the state in which the first large diameter portion 22 is in contact with the protruding portion 18 by the rotational friction of each vane 15. At this time, as shown in FIG. 3, the discharge amount of the hydraulic fluid from the first discharge port 35 and the second discharge port 36 is maximum. When the rotational speed of the drive shaft 11 rises from this state, the discharge amount increases in proportion to the rotational speed.

When the rotational speed of the drive shaft 11 reaches a predetermined rotational speed, the pressure difference between the high pressure chamber 46 and the intermediate pressure chamber 47 becomes equal to or greater than the predetermined pressure difference. For this reason, the spool 43 of the control valve 29 moves to the other side in the axial direction (the right side in FIG. 1) against the urging force of the spring 44. As a result, high-pressure hydraulic fluid is introduced into the main cam control chamber 25 from the discharge passage 27, and the pressure difference between the main cam control chamber 25 and the sub cam control chamber 26 increases. Accordingly, the cam ring 8 rotates in the clockwise direction in FIG. 1 against the rotational friction of each vane 15. When the cam ring 8 rotates, the amount of hydraulic fluid discharged from the first discharge port 35 and the second discharge port 36 decreases as shown in FIG. When the discharge amount is reduced, the pressure difference between the high pressure chamber 46 and the intermediate pressure chamber 47 is less than the predetermined pressure difference, so that the spool 43 moves to one side in the axial direction (left side in FIG. 1) by the urging force of the spring 44. Therefore, the main cam control chamber 25 communicates with the suction passage 30 and the pressure in the main cam control chamber 25 decreases. As a result, the cam ring 8 is rotated in the counterclockwise direction in FIG. 1 by the rotational friction of each vane 15. When the cam ring 8 rotates, the pressure difference between the high pressure chamber 46 and the intermediate pressure chamber 47 increases again, and the spool 43 moves to the other side in the axial direction against the urging force of the spring 44. That is, when the rotation speed of the drive shaft 11 exceeds a predetermined rotation speed, the discharge amount is maintained constant regardless of the rotation speed.

Next, the function and effect of the variable displacement pump 1 of the first embodiment will be described.
In the variable displacement pump 1, the first suction region, the second suction region, the first discharge region, and the second discharge region are arranged at symmetrical positions with respect to the rotation axis O. Therefore, since a bending force due to a lateral load does not act on the drive shaft 11, a pressure balance with respect to the drive shaft 11 can be achieved, and pulsation and vibration can be suppressed. Further, since the drive shaft 11 is not subjected to bending force, the shaft diameter of the drive shaft 11 and the bearings 12 and 13 can be reduced, and the variable displacement pump 1 can be reduced in size.
In the variable displacement pump 1, the first discharge port 35 and the second discharge port 36, the first suction port 33 and the second suction port in each pump chamber 16 when the cam ring 8 rotates according to the increase in the rotation speed of the drive shaft 11. By changing the relative position of the port 34 and the pump volume, the discharge amount can be made variable. For this reason, useless power loss can be suppressed in supplying hydraulic fluid to the power steering device.

The variable displacement pump 1 has a bearing 50 that supports the cam ring 8 on the opposite side of the region (main cam control chamber 25) between the pair of cam seals 19, 24 with respect to the rotation axis O in the radial direction. The cam ring 8 is urged in the direction of the bearing 50 by a pair of cam seals 19, 24 and high-pressure hydraulic fluid introduced into the main cam control chamber 25, and is supported by the bearing 50 so as to be rotatable about the axis. Thereby, positional deviation (eccentricity) of the cam ring 8 and friction during rotation can be reduced, and the cam ring 8 can be smoothly rotated.
The bearing 50 is located on the opposite side of the main cam control chamber 25 with respect to the rotation axis O regardless of the volume of the main cam control chamber 25. Therefore, when the circumferential width of the main cam control chamber 25 is a half of the maximum width, the bearing 50 is located at a symmetrical position with respect to the rotation axis O at the central position in the circumferential direction of the main cam control chamber 25. ing. Since the bearing 50 is disposed at a well-balanced position with respect to both the state in which the main cam control chamber 25 has the maximum volume and the state in which the main volume reaches the minimum volume, the rotation controllability of the cam ring 8 in the entire operation region can be improved. Further, the bearing 50 overlaps with the axis along the direction of the combined vector of the forces that the pressure of the main cam control chamber 25 acts on the small diameter portion 21 and the first large diameter portion 22 of the cam ring 8. As a result, the force of the main cam control chamber 25 acting on the cam ring 8 can be appropriately received by the bearing 50.

The small-diameter portion 21 of the cam ring 8 overlaps the boundary between the second discharge region and the first suction region in the circumferential direction, and the boundary between the first suction region and the first discharge region and the first discharge region. It is provided at a position that does not overlap the boundary between the two suction areas and the second discharge area. That is, the small diameter portion 21 is provided in a portion where the inner diameter of the cam ring 8 is small, and the small diameter portion 21 is not provided in a portion where the inner diameter of the cam ring 8 is large. Therefore, there is no portion in which the radial thickness (wall thickness) of the cam ring 8 becomes extremely small, and the rigidity of the cam ring 8 can be ensured.
The housing 2 opens to the sub cam control chamber 26 which is a space between the second large diameter portion 23 of the cam ring 8 and the protruding portion 18 of the adapter ring portion 9, and introduces suction pressure for introducing the working fluid of the suction passage 30. A passage 41 is provided. As a result, it is difficult for hydraulic fluid to leak from the auxiliary cam control chamber 26, and pump efficiency can be improved. In addition, by introducing the hydraulic fluid from the suction passage 30 into the sub cam control chamber 26, the pressure of the hydraulic fluid supplied to the main cam control chamber 25 can be set lower than when no hydraulic fluid is introduced. The leakage of hydraulic fluid from the cam control chamber 25 can be suppressed.

The opening end 41a of the suction pressure introduction passage 41 in the sub cam control chamber 26 is disposed at a position where it is not blocked by the second large diameter portion 23 even when the sub cam control chamber 26 has a minimum volume. If the open end 41a is closed by the second large diameter portion 23, when the volume of the sub cam control chamber 26 is increased again, the pressure in the sub cam control chamber 26 becomes negative, and the controllability of the cam ring 8 is reduced. May be exacerbated. Therefore, even in a state where the sub cam control chamber 26 has the minimum volume, at least a part of the opening end 41a opens into the sub cam control chamber 26, so that the controllability of the cam ring 8 can be suppressed.
The rotation direction of the cam ring 8 and the rotation direction of the drive shaft 11 when the volume of the main cam control chamber 25 increases are opposite directions. In other words, the direction in which the cam ring 8 rotates in the direction in which the volume of the main cam control chamber 25 decreases coincides with the direction in which the drive shaft 11 rotates. When rotating the cam ring 8 in the direction in which the volume of the main cam control chamber 25 increases, the tip of each vane 15 that rotates as the drive shaft 11 rotates contacts the inner cam surface 8 a of the cam ring 8. By rotating the cam ring 8 using this rotational friction, the main cam control chamber 25 can be returned to the minimum volume without controlling the pressure in the sub cam control chamber 26. That is, the rotational friction of each vane 15 can be effectively used for driving control of the cam ring 8.

The main cam control chamber 25 has a stepped portion 22a that abuts against the protruding portion 18 when the volume is minimum and forms a space between the first large diameter portion 22 and the protruding portion 18. If the volume of the main cam control chamber 25 becomes 0, when the volume of the main cam control chamber 25 is increased again, the pressure in the main cam control chamber 25 becomes negative and the controllability of the cam ring 8 may be deteriorated. is there. Therefore, even when the main cam control chamber 25 has a minimum volume, the controllability of the cam ring 8 can be prevented from decreasing by keeping the volume of the main cam control chamber 25 from becoming zero.
The first suction port 33 is provided adjacent to a first confinement region where one of the pump chambers 16 does not communicate with either the first suction port 33 or the first discharge port 35. The second suction port 34 is provided adjacent to a second confinement region in which one of the pump chambers 16 does not communicate with either the second suction port 34 or the second discharge port 36. . As the cam ring 8 rotates, the hydraulic fluid in the first confinement region and the second confinement region may be in a compressed state. Here, if the compressed hydraulic fluid is not easily removed, the compressed state continues, leading to a drive loss of the pump. Since the first suction port 33 and the second suction port 34 are adjacent to the first confinement region and the second confinement region, the compressed hydraulic fluid is immediately discharged to the first suction port 33 and the second suction port 34. Therefore, the drive loss of the pump can be reduced.
The second suction port 34 has an extension 34a that extends to a region between the cam ring 8 and the bearing 50 in the radial direction. By supplying the working fluid to the region between the bearing 50 and the cam ring 8 via the extension 34a, the lubricity of the cam ring support portion by the bearing 50 can be improved.
Since the adapter ring portion 9 has a bearing holding portion 9b that is recessed radially outward on the inner peripheral surface thereof, the arrangement of the bearing 50 that is a needle bearing is easy.

[Embodiment 2]
Next, Embodiment 2 will be described. Since the basic configuration of the second embodiment is the same as that of the first embodiment, only portions different from the first embodiment will be described.
FIG. 5 is a schematic diagram of a main part of the variable displacement pump 51 of the second embodiment.
The variable displacement pump 1 of the second embodiment is different from the first embodiment in that a spring (elastic member) 52 is provided between the second large diameter portion 23 and the protruding portion 18 in the circumferential direction. The spring 52 is a compression coil spring. The spring 52 biases the cam ring 8 in the direction in which the volume of the sub cam control chamber 26 increases. In the first embodiment, when the discharge amount of the variable displacement pump 1 is increased, the cam ring 8 is rotated by the rotational friction of each vane 15. On the other hand, in the second embodiment, when the discharge amount of the variable displacement pump 51 is increased, the cam ring 8 is rotated counterclockwise in FIG. 5 by the rotational friction of each vane 15 and the biasing force of the spring 52. . Thereby, the responsiveness at the time of increasing the discharge amount can be improved as compared with the first embodiment.

[Embodiment 3]
Next, Embodiment 3 will be described. Since the basic configuration of the third embodiment is the same as that of the first embodiment, only the differences from the first embodiment will be described.
FIG. 6 is a schematic diagram of the variable displacement pump 53 of the third embodiment.
The first suction port 33 and the second suction port 34 are connected to the suction passage 30. The hydraulic fluid flowing into the suction passage 30 from the reservoir tank 31 passes through the suction passage 30 and is sucked into the pump chambers 16 from the first suction port 33 and the second suction port 34. The hydraulic fluid introduced into each pump chamber 16 is sequentially compressed according to the movement of each vane 15, passes through the discharge passages 39 and 40 and the discharge passage 27 from the first discharge port 35 and the second discharge port 36, and moves to the housing 2. It is discharged to the outside.

In the rear housing 4, a downstream pressure introduction passage 54 connected to the valve hole 42 is formed. The downstream pressure introduction passage 54 is connected to the downstream pressure introduction passage 9c formed in the adapter ring portion 9. The downstream pressure introduction passage 9 c passes through the adapter ring portion 9 in the radial direction and opens into the sub cam control chamber 26. When the pressure difference between the intermediate pressure chamber 47 and the high pressure chamber 46 is less than a predetermined pressure difference, the spool 43 maintains a state where it abuts against the end surface 42a of the valve hole 42 by the urging force of the spring 44. At this time, the upstream pressure introduction passage 45 is in communication with the low pressure chamber 48, and the working fluid of the low pressure chamber 48 is introduced into the main cam control chamber 25. On the other hand, the downstream pressure introduction passage 54 is in communication with the intermediate pressure chamber 47, and the hydraulic fluid in the intermediate pressure chamber 47 is introduced into the sub cam control chamber 26. When the pressure difference between the intermediate pressure chamber 47 and the high pressure chamber 46 exceeds a predetermined pressure difference, the spool 43 moves to the other side in the axial direction (the right side in FIG. 6) against the urging force of the spring 44. At this time, the upstream pressure introduction passage 45 is in communication with the high pressure chamber 46, and the working fluid of the high pressure chamber 46 is introduced into the main cam control chamber 25. On the other hand, the downstream pressure introduction passage 54 is in communication with the low pressure chamber 48, and the working fluid is discharged from the sub cam control chamber 26 to the low pressure chamber 48.

Next, the operation of the variable displacement pump 53 of the third embodiment will be described.
When the rotational speed of the drive shaft 11 is less than the predetermined rotational speed, the pressure loss of the metering orifice 28 is very small, so the pressure difference between the high pressure chamber 46 and the intermediate pressure chamber 47 is less than the predetermined pressure difference. Therefore, the spool 43 of the control valve 29 is maintained in contact with the end surface 42a by the urging force of the spring 44. Therefore, the low pressure hydraulic fluid is introduced into the main cam control chamber 25 from the suction passage 30. On the other hand, medium pressure hydraulic fluid is introduced into the secondary cam control chamber 26 from the downstream side of the metering orifice 28 of the discharge passage 27. Since the pressure difference between the main cam control chamber 25 and the sub cam control chamber 26 is large, the cam ring 8 maintains the state where the first large diameter portion 22 is in contact with the protruding portion 18 against the rotational friction of each vane 15. To do. At this time, the discharge amount of the hydraulic fluid from the first discharge port 35 and the second discharge port 36 is maximum. When the rotational speed of the drive shaft 11 rises from this state, the discharge amount increases in proportion to the rotational speed.

When the rotational speed of the drive shaft 11 reaches a predetermined rotational speed, the pressure difference between the high pressure chamber 46 and the intermediate pressure chamber 47 becomes equal to or greater than the predetermined pressure difference. For this reason, the spool 43 of the control valve 29 moves to the other side in the axial direction (the right side in FIG. 6) against the urging force of the spring 44. As a result, high-pressure hydraulic fluid is introduced into the main cam control chamber 25 from the discharge passage 27. On the other hand, the hydraulic fluid is discharged from the auxiliary cam control chamber 26 through communication with the suction passage 30. Therefore, the pressure difference between the main cam control chamber 25 and the sub cam control chamber 26 is reduced. Therefore, the cam ring 8 rotates counterclockwise in FIG. 6 due to the rotational friction of each vane 15. When the cam ring 8 rotates, the amount of hydraulic fluid discharged from the first discharge port 35 and the second discharge port 36 decreases. When the discharge amount is reduced, the pressure difference between the high pressure chamber 46 and the intermediate pressure chamber 47 is less than the predetermined pressure difference, so that the spool 43 moves to one side in the axial direction (left side in FIG. 6) by the urging force of the spring 44. Therefore, the main cam control chamber 25 communicates with the suction passage 30 and the pressure in the main cam control chamber 25 decreases. At the same time, the secondary cam control chamber 26 communicates with the downstream side of the metering orifice 28 in the discharge passage 27, and the pressure in the secondary cam control chamber 26 increases. As a result, the pressure difference between the main cam control chamber 25 and the sub cam control chamber 26 increases, so that the cam ring 8 rotates in the clockwise direction in FIG. 6 against the rotational friction of each vane 15. When the cam ring 8 rotates, the pressure difference between the high pressure chamber 46 and the intermediate pressure chamber 47 increases again, and the spool 43 moves to the other side in the axial direction against the urging force of the spring 44. That is, when the rotation speed of the drive shaft 11 exceeds a predetermined rotation speed, the discharge amount is maintained constant regardless of the rotation speed.

Next, the function and effect of the variable displacement pump 53 of the third embodiment will be described.
The housing 2 has a downstream pressure introduction passage 54 that opens into the sub cam control chamber 26 that is a space between the second large diameter portion 23 and the protruding portion 18 and that introduces pressure downstream of the metering orifice 28. . By introducing the discharge pressure into the sub cam control chamber 26, the operability of the cam ring 8 when the volume of the sub cam control chamber 26 is increased can be improved.
The direction in which the cam ring 8 rotates in the direction in which the volume of the sub cam control chamber 26 decreases matches the direction in which the drive shaft 11 rotates. Thereby, when the cam ring 8 is rotated in the direction in which the volume of the main cam control chamber 25 increases, the rotational friction of each vane 15 can be effectively used for the drive control of the cam ring 8.
The control valve 29 controls the pressure in the main cam control chamber 25 and holds the position of the cam ring 8. That is, the control valve 29 controls the pressure in the main cam control chamber 25 so as to balance the rotational torque of the cam ring 8 generated by the rotational friction of each vane 15. As a result, highly accurate position control of the cam ring 8 can be realized while effectively using the rotational friction of each vane 15 for drive control of the cam ring 8.

[Embodiment 4]
Next, a fourth embodiment will be described. Since the basic configuration of the fourth embodiment is the same as that of the third embodiment, only the differences from the third embodiment will be described.
FIG. 7 is a schematic diagram of a main part of the variable displacement pump 55 of the fourth embodiment.
The variable displacement pump 1 according to the fourth embodiment is different from the third embodiment in that a spring (elastic member) 56 is provided between the second large diameter portion 23 and the protruding portion 18 in the circumferential direction. The spring 56 is a compression coil spring. The spring 56 biases the cam ring 8 in the direction in which the volume of the sub cam control chamber 26 increases. In the third embodiment, when the discharge amount of the variable displacement pump 53 is increased, the cam ring 8 is rotated by a pressure difference between the high pressure chamber 46 and the intermediate pressure chamber 47. In contrast, in the fourth embodiment, when the discharge amount of the variable displacement pump 55 is increased, the cam ring 8 is rotated clockwise in FIG. 7 by the pressure difference between the high pressure chamber 46 and the intermediate pressure chamber 47 and the biasing force of the spring 56. Rotate in the direction of. Thereby, it is possible to improve the responsiveness when increasing the discharge amount as compared with the third embodiment.

[Other Embodiments]
Although the embodiment for carrying out the present invention has been described above, the specific configuration of the present invention is not limited to the configuration of the embodiment, and there are design changes and the like within the scope not departing from the gist of the invention. Are also included in the present invention.
For example, the bearing 50 may be a bimetal type.
The embodiment of the present invention can be applied to a pump used as a fluid pressure generation source in a pressure fluid utilization device other than a power steering device.

The technical idea that can be grasped from the embodiment described above will be described below.
In one embodiment, the variable displacement pump includes a housing having a pump element accommodating portion therein, a drive shaft that is pivotally supported by the housing, and a rotor that is rotationally driven by the drive shaft, the drive shaft A rotor having a plurality of slots provided in a direction around a rotation axis of the rotor, a plurality of vanes provided in each of the slots of the rotor, and the rotor and the plurality of vanes provided in the pump element accommodating portion. An encircling annular cam ring, wherein the cam ring, the rotor, and the plurality of vanes form a plurality of pump chambers, and each volume of the plurality of pump chambers increases as the rotor rotates. A first discharge region that is a pair of regions in which the respective volumes of the plurality of pump chambers are reduced. And the second discharge region, the first suction region and the second suction region are arranged symmetrically with respect to the rotation axis of the drive shaft, and the first discharge region and the second discharge region are The volumes of the plurality of pump chambers in the first suction region and the second suction region are arranged in symmetrical positions, and the cam ring is rotated in a direction around the rotation axis of the drive shaft with respect to the housing. A cam ring that changes a ratio between an increase amount and a decrease amount of the volume of the plurality of pump chambers in the first discharge region and the second discharge region; and the housing, the first suction region and the second suction region A suction passage that opens to a region and supplies hydraulic fluid to the first suction region and the second suction region; and the housing, the first discharge region and the second discharge region. A discharge passage that opens to a region and discharges hydraulic fluid from the first discharge region and the second discharge region to the outside of the housing; and the pump element housing portion and the cam ring in a radial direction of the rotation axis of the drive shaft A first seal member and a second seal member which are a pair of seal members provided between the outer peripheral sides of the first and second seal members, and a main cam control chamber is formed between the first seal member and the second seal member. A bearing provided between the first seal member, the second seal member, and the outer peripheral side of the cam ring in the radial direction of the rotation axis of the drive shaft, the rotation axis of the drive shaft On the other hand, a bearing provided on the opposite side of the first seal member or the second seal member, and a control valve for controlling the pressure in the main cam control chamber.

In a more preferred aspect, in the above aspect, the bearing is located on the opposite side of the region between the first seal member and the second seal member with respect to the rotation axis of the drive shaft.
In another preferred aspect, in any one of the above aspects, when the bearing has a circumferential width in the rotation axis of the drive shaft of the main cam control chamber that is half the maximum width, It is located at a symmetrical position of the central position of the main cam control chamber with respect to the rotation axis.
In still another preferred aspect, in any one of the above aspects, the protrusion is provided on the housing, and includes a protrusion that protrudes inward in the radial direction of the rotation axis of the drive shaft, and the cam ring includes A small diameter portion having a first outer diameter as an outer diameter that is a distance from a rotation axis of the drive shaft to an outer peripheral edge of the cam ring, and provided on both sides of the small diameter portion in a direction around the rotation axis of the drive shaft. A first large diameter portion and a second large diameter portion which are a pair of large diameter portions having a second outer diameter whose outer diameter is larger than the first outer diameter, and the protrusion is a rotation of the drive shaft Arranged between the first large diameter portion and the second large diameter portion in the direction around the axis, and the main cam control chamber is provided in a region between the first large diameter portion and the protrusion, The bearing is in relation to the small diameter portion and the first large diameter portion. Serial pressure main cam control chamber overlaps the axis along the direction of the resultant vector of the force acting.

In still another preferred aspect, in any one of the above aspects, the protrusion is provided on the housing, and includes a protrusion that protrudes inward in the radial direction of the rotation axis of the drive shaft, and the cam ring includes A small diameter portion having a first outer diameter as an outer diameter that is a distance from a rotation axis of the drive shaft to an outer peripheral edge of the cam ring, and provided on both sides of the small diameter portion in a direction around the rotation axis of the drive shaft. A first large diameter portion and a second large diameter portion which are a pair of large diameter portions having a second outer diameter whose outer diameter is larger than the first outer diameter, and the protrusion is a rotation of the drive shaft Arranged between the first large diameter portion and the second large diameter portion in the direction around the axis, and the main cam control chamber is provided in a region between the first large diameter portion and the protrusion, A first suction region, a second suction region, and the first discharge The region and the second discharge region are arranged in the order of the first suction region, the first discharge region, the second suction region, and the second discharge region along the rotation direction of the rotor, In a direction around the rotation axis of the drive shaft, the boundary between the second discharge region and the first suction region overlaps, and the boundary between the first suction region and the first discharge region and the first It is provided at a position that does not overlap the boundary between the two suction areas and the second discharge area.
In still another preferred aspect, in any one of the above aspects, the protrusion is provided on the housing, and includes a protrusion that protrudes inward in the radial direction of the rotation axis of the drive shaft, and the cam ring includes A small diameter portion having a first outer diameter as an outer diameter that is a distance from a rotation axis of the drive shaft to an outer peripheral edge of the cam ring, and provided on both sides of the small diameter portion in a direction around the rotation axis of the drive shaft. A first large diameter portion and a second large diameter portion which are a pair of large diameter portions having a second outer diameter whose outer diameter is larger than the first outer diameter, and the protrusion is a rotation of the drive shaft Arranged between the first large diameter portion and the second large diameter portion in the direction around the axis, and the main cam control chamber is provided in a region between the first large diameter portion and the protrusion, The housing includes the second large diameter portion and the protruding portion. Open to is spatial sub cam control chamber, having a suction pressure introduction passage for introducing the working fluid of the suction passage.

In still another preferred aspect, in any one of the above aspects, the opening on the side of the sub cam control chamber of the suction pressure introduction passage is configured to have the second large diameter even when the volume of the sub cam control chamber is minimized. It is provided at a position that is not blocked by the part.
In still another preferred aspect, in any one of the above aspects, the rotation direction of the cam ring and the rotation direction of the drive shaft when the volume of the main cam control chamber increases are opposite to each other.
In still another preferred aspect, in any one of the above aspects, the protrusion is provided on the housing, and includes a protrusion that protrudes inward in the radial direction of the rotation axis of the drive shaft, and the cam ring includes A small diameter portion having a first outer diameter as an outer diameter that is a distance from a rotation axis of the drive shaft to an outer peripheral edge of the cam ring, and provided on both sides of the small diameter portion in a direction around the rotation axis of the drive shaft. A first large diameter portion and a second large diameter portion which are a pair of large diameter portions having a second outer diameter whose outer diameter is larger than the first outer diameter, and the protrusion is a rotation of the drive shaft Arranged between the first large diameter portion and the second large diameter portion in the direction around the axis, and the main cam control chamber is provided in a region between the first large diameter portion and the protrusion, Step portion provided on the first large diameter portion or the protruding portion When the volume of the main cam control chamber is minimized, the stepped portion comes into contact with the first large diameter portion or the protruding portion, so that the first large diameter portion and the first large diameter portion in a region other than the stepped portion. It further has a step part which forms a space between the protrusions.

In still another preferred aspect, in any one of the above aspects, the first discharge region and the second discharge region in the first discharge region and the second discharge region with respect to an increase in volume of the plurality of pump chambers in the first suction region and the second suction region. An elastic member that urges the cam ring in a direction in which the cam ring rotates in a direction in which a rate of decrease in volume of the plurality of pump chambers decreases;
In still another preferred aspect, in any one of the above aspects, the first suction area, the second suction area, the first discharge area, and the second discharge area are arranged along the rotation direction of the rotor. The suction region, the first discharge region, the second suction region, and the second discharge region are arranged in this order, and the suction passage is provided in the first suction port that opens to the first suction region, and the second suction region. A plurality of pump chambers, wherein the plurality of pump chambers have a first suction port that opens to the first discharge region and a second discharge port that opens to the second discharge region; A region between one of the first suction port and the first discharge port and not communicating with either the first suction port or the first discharge port is defined as a first confinement region. A plurality of pump chambers When one of the regions is between the second suction port and the second discharge port and does not communicate with either the second suction port or the second discharge port, the second confinement region The first suction port is provided adjacent to the first confinement region, and the second suction port is provided adjacent to the second confinement region.

In still another preferred aspect, in any one of the above aspects, the first suction area, the second suction area, the first discharge area, and the second discharge area are arranged along the rotation direction of the rotor. The suction region, the first discharge region, the second suction region, and the second discharge region are arranged in this order, and the suction passage is provided in the first suction port that opens to the first suction region, and the second suction region. A second suction port that opens to the first discharge region; a second discharge port that opens to the second discharge region; and the second suction port. Is formed so as to extend to a region between the cam ring and the bearing in the radial direction of the rotation axis of the drive shaft.
In yet another preferred aspect, in any one of the above aspects, a protrusion provided in the housing, the protrusion projecting inward in the radial direction of the rotation axis of the drive shaft, and the discharge passage. A metering orifice provided, and the cam ring includes a small-diameter portion having a first outer diameter whose outer diameter is a distance from a rotation axis of the drive shaft to an outer peripheral edge of the cam ring, and rotation of the drive shaft. A first large-diameter portion and a second large-diameter portion, which are a pair of large-diameter portions provided on both sides of the small-diameter portion in a direction around the axis and having a second outer diameter that is larger than the first outer diameter. And the projecting portion is disposed between the first large diameter portion and the second large diameter portion in a direction around the rotation axis of the drive shaft, and the main cam control chamber has the first large diameter In the area between the The pressure upstream of the metering orifice is introduced, and the housing opens into a secondary cam control chamber, which is a space between the second large diameter portion and the protruding portion, and more than the metering orifice. A downstream pressure introduction passage for introducing downstream pressure is provided.

In still another preferred aspect, in any one of the above aspects, a direction in which the cam ring rotates in a direction in which the volume of the sub cam control chamber decreases and a direction in which the drive shaft rotates.
In still another preferred aspect, in any of the above aspects, the control valve controls the pressure in the main cam control chamber to maintain the position of the cam ring.
In still another preferred aspect, in any one of the above aspects, the first discharge region and the second discharge region in the first discharge region and the second discharge region with respect to an increase in volume of the plurality of pump chambers in the first suction region and the second suction region. An elastic member that urges the cam ring in a direction in which the cam ring rotates in a direction in which a rate of decrease in volume of the plurality of pump chambers decreases;
In still another preferred aspect, in any one of the above aspects, the housing includes an annular adapter ring portion that surrounds the cam ring, and the adapter ring portion extends from a rotation axis of the drive shaft to the adapter ring portion. The inner diameter of the adapter ring portion, which is the distance to the inner peripheral surface, is larger in the region where the bearing is provided than in the region where the first seal member is in sliding contact with the inner peripheral surface of the adapter ring portion. It has the bearing holding part formed in the area | region provided.
In still another preferred aspect, in any one of the above aspects, the protrusion is provided on the housing, and includes a protrusion that protrudes inward in the radial direction of the rotation axis of the drive shaft, and the cam ring includes A small diameter portion having a first outer diameter as an outer diameter that is a distance from a rotation axis of the drive shaft to an outer peripheral edge of the cam ring, and provided on both sides of the small diameter portion in a direction around the rotation axis of the drive shaft. A first large diameter portion and a second large diameter portion which are a pair of large diameter portions having a second outer diameter whose outer diameter is larger than the first outer diameter, and the protrusion is a rotation of the drive shaft Arranged between the first large diameter portion and the second large diameter portion in the direction around the axis, and the main cam control chamber is provided in a region between the first large diameter portion and the protrusion, The cam in the direction of decreasing the volume of the main cam control chamber Ring and the rotation direction of the drive shaft and the direction of rotation are matched.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

This application claims priority based on Japanese Patent Application No. 2017-22687 filed on Feb. 10, 2017. The entire disclosure including the specification, claims, drawings, and abstract of Japanese Patent Application No. 2017-22687 filed on February 10, 2017 is incorporated herein by reference in its entirety.

1,51,53,55 Variable displacement pump 2 Housing 5 Pump element housing 7 Rotor 7a Slot 8 Cam ring 9 Adapter ring 9b Bearing holder 11 Drive shaft 15 Vane 16 Pump chamber 18 Projection 19 Cam seal (first seal member ) 21 Small diameter portion 22 First large diameter portion 22a Step portion 23 Second large diameter portion 24 Cam seal (second seal member) 25 Main cam control chamber 26 Sub cam control chamber 27 Discharge passage 28 Metering orifice 29 Control valve 30 Intake passage 30a suction passage 30b suction passage 33 first suction port 34 second suction port 35 first discharge port 36 second discharge port 41 suction pressure introduction passage 50 bearing 52 spring (elastic member) 54 downstream pressure introduction passage 56 spring (elastic member) O Rotation axis

Claims (18)

A variable displacement pump, the variable displacement pump being
A housing having a pump element housing therein;
A drive shaft supported by the housing;
A rotor that is rotationally driven by the drive shaft, the rotor having a plurality of slots provided in a direction around a rotation axis of the drive shaft;
A plurality of vanes provided in each of the slots of the rotor;
An annular cam ring provided in the pump element accommodating portion and surrounding the rotor and the plurality of vanes;
A plurality of pump chambers are formed in the pump element housing portion by the cam ring, the rotor, and the plurality of vanes,
The plurality of pump chambers are:
A first suction area and a second suction area, which are a pair of areas in which the respective volumes increase as the rotor rotates,
Having a first discharge area and a second discharge area, which are a pair of areas in which the respective volumes decrease as the rotor rotates.
The first suction area and the second suction area are arranged at symmetrical positions with respect to the rotation axis of the drive shaft;
The first discharge area and the second discharge area are arranged at symmetrical positions with respect to the rotation axis of the drive shaft,
By rotating the cam ring in a direction around the rotation axis of the drive shaft with respect to the housing, an increase in volume of the plurality of pump chambers in the first suction region and the second suction region, and the first The ratio between the discharge area and the volume reduction amount of the plurality of pump chambers in the second discharge area can be changed,
The variable displacement pump also has
A suction passage provided in the housing, opening to the first suction region and the second suction region, and supplying hydraulic fluid to the first suction region and the second suction region;
A discharge passage that is provided in the housing, opens to the first discharge region and the second discharge region, and discharges hydraulic fluid from the first discharge region and the second discharge region to the outside of the housing;
A first seal member and a second seal member which are a pair of seal members provided between the pump element housing portion and the outer peripheral side of the cam ring in the radial direction of the rotation axis of the drive shaft, The first seal member and the second seal member forming a main cam control chamber between the first seal member and the second seal member;
A bearing provided between the pump element housing portion and the outer peripheral side of the cam ring in the radial direction of the rotation axis of the drive shaft, wherein the first seal member or the first seal member with respect to the rotation axis of the drive shaft The bearing provided on the opposite side of the two sealing members;
A control valve for controlling the pressure in the main cam control chamber;
A variable displacement pump. The variable displacement pump according to claim 1, wherein
The said bearing is a variable displacement pump located in the other side of the area | region between the said 1st seal member and the said 2nd seal member with respect to the rotating shaft line of the said drive shaft. The variable displacement pump according to claim 2,
The bearing has a central position of the main cam control chamber with respect to the rotation axis of the drive shaft when the circumferential width of the rotation axis of the drive shaft of the main cam control chamber is half the maximum width. Variable displacement pump located at a symmetrical position. The variable displacement pump according to claim 3,
The variable displacement pump is a protrusion provided in the housing, and includes a protrusion that protrudes inward in the radial direction of the rotation axis of the drive shaft,
The cam ring is
A small-diameter portion having an outer diameter that is a distance from the rotation axis of the drive shaft to the outer peripheral edge of the cam ring, the first outer diameter;
A first large-diameter portion that is a pair of large-diameter portions provided on both sides of the small-diameter portion in a direction around the rotation axis of the drive shaft and having a second outer diameter that is larger than the first outer diameter; A second large diameter portion,
The protrusion is disposed between the first large diameter portion and the second large diameter portion in a direction around the rotation axis of the drive shaft,
The main cam control chamber is provided in a region between the first large diameter portion and the protruding portion,
The said bearing is a variable displacement pump which overlaps with the axis line along the direction of the synthetic vector of the force which the pressure of the said main cam control chamber acts with respect to the said small diameter part and the said 1st large diameter part. The variable displacement pump according to claim 1, wherein
A projecting portion provided in the housing, the projecting portion projecting inward in the radial direction of the rotation axis of the drive shaft;
The cam ring is
A small-diameter portion having an outer diameter that is a distance from the rotation axis of the drive shaft to the outer peripheral edge of the cam ring, the first outer diameter;
A first large-diameter portion that is a pair of large-diameter portions provided on both sides of the small-diameter portion in a direction around the rotation axis of the drive shaft and having a second outer diameter that is larger than the first outer diameter; A second large diameter portion,
The protrusion is disposed between the first large diameter portion and the second large diameter portion in a direction around the rotation axis of the drive shaft,
The main cam control chamber is provided in a region between the first large diameter portion and the protruding portion,
The first suction region, the second suction region, the first discharge region, and the second discharge region are the first suction region, the first discharge region, and the second suction region along the rotation direction of the rotor. , Arranged in the order of the second discharge region,
The small diameter portion overlaps a boundary between the second discharge region and the first suction region in a direction around the rotation axis of the drive shaft, and the first suction region and the first discharge region And a variable displacement pump provided at a position that does not overlap the boundary between the second suction area and the boundary between the second suction area and the second discharge area. The variable displacement pump according to claim 1, wherein
A projecting portion provided in the housing, the projecting portion projecting inward in the radial direction of the rotation axis of the drive shaft;
The cam ring is
A small-diameter portion having an outer diameter that is a distance from the rotation axis of the drive shaft to the outer peripheral edge of the cam ring, the first outer diameter;
A first large-diameter portion that is a pair of large-diameter portions provided on both sides of the small-diameter portion in a direction around the rotation axis of the drive shaft and having a second outer diameter that is larger than the first outer diameter; A second large diameter portion,
The protrusion is disposed between the first large diameter portion and the second large diameter portion in a direction around the rotation axis of the drive shaft,
The main cam control chamber is provided in a region between the first large diameter portion and the protruding portion,
The housing is a variable displacement pump having a suction pressure introduction passage that opens into a sub cam control chamber, which is a space between the second large diameter portion and the protrusion, and introduces hydraulic fluid in the suction passage. The variable displacement pump according to claim 6,
The variable pressure pump provided at the position where the suction cam introduction passage on the side of the secondary cam control chamber is not blocked by the second large diameter portion even when the volume of the secondary cam control chamber is minimized. . The variable displacement pump according to claim 6,
A variable displacement pump in which the rotation direction of the cam ring and the rotation direction of the drive shaft are opposite when the volume of the main cam control chamber increases. The variable displacement pump according to claim 1, wherein
The variable displacement pump is a protrusion provided in the housing, and includes a protrusion that protrudes inward in the radial direction of the rotation axis of the drive shaft,
The cam ring is
A small-diameter portion having an outer diameter that is a distance from the rotation axis of the drive shaft to the outer peripheral edge of the cam ring, the first outer diameter;
A first large-diameter portion that is a pair of large-diameter portions provided on both sides of the small-diameter portion in a direction around the rotation axis of the drive shaft and having a second outer diameter that is larger than the first outer diameter; A second large diameter portion,
The protrusion is disposed between the first large diameter portion and the second large diameter portion in a direction around the rotation axis of the drive shaft,
The main cam control chamber is provided in a region between the first large diameter portion and the protruding portion,
The variable displacement pump is
A step provided in the first large diameter portion or the protrusion, and when the volume of the main cam control chamber is minimized, the step contacts the first large diameter portion or the protrusion. Thus, the variable displacement pump further comprising the step portion that forms a space between the first large diameter portion and the protruding portion in a region other than the step portion. The variable displacement pump according to claim 1, wherein
The variable displacement pump is
The ratio of the decrease amount of the volume of the plurality of pump chambers in the first discharge region and the second discharge region to the increase amount of the volume of the plurality of pump chambers in the first suction region and the second suction region becomes small. A variable displacement pump having an elastic member that biases the cam ring in a direction in which the cam ring rotates. The variable displacement pump according to claim 1, wherein
The first suction region, the second suction region, the first discharge region, and the second discharge region are the first suction region, the first discharge region, and the second suction region along the rotation direction of the rotor. , Arranged in the order of the second discharge region,
The suction passage has a first suction port that opens to the first suction region, and a second suction port that opens to the second suction region;
The discharge passage has a first discharge port that opens to the first discharge region, and a second discharge port that opens to the second discharge region,
An area in which one of the plurality of pump chambers is between the first suction port and the first discharge port and is not in communication with either the first suction port or the first discharge port. A first confining region, and one of the plurality of pump chambers is between the second suction port and the second discharge port, and in which of the second suction port and the second discharge port When the region that is not in communication is the second confinement region, the first suction port is provided adjacent to the first confinement region, and the second suction port is disposed in the second confinement region. A variable displacement pump installed adjacent to it. The variable displacement pump according to claim 1, wherein
The first suction region, the second suction region, the first discharge region, and the second discharge region are the first suction region, the first discharge region, and the second suction region along the rotation direction of the rotor. , Arranged in the order of the second discharge region,
The suction passage has a first suction port that opens to the first suction region, and a second suction port that opens to the second suction region;
The discharge passage has a first discharge port that opens to the first discharge region, and a second discharge port that opens to the second discharge region,
The second suction port is a variable displacement pump formed so as to extend to a region between the cam ring and the bearing in the radial direction of the rotation axis of the drive shaft. The variable displacement pump according to claim 1, wherein
The variable displacement pump is
A protrusion provided in the housing, the protrusion protruding inward in the radial direction of the rotation axis of the drive shaft;
A metering orifice provided in the discharge passage;
With
The cam ring is
A small-diameter portion having an outer diameter that is a distance from the rotation axis of the drive shaft to the outer peripheral edge of the cam ring, the first outer diameter;
A first large-diameter portion that is a pair of large-diameter portions provided on both sides of the small-diameter portion in a direction around the rotation axis of the drive shaft and having a second outer diameter that is larger than the first outer diameter; A second large diameter portion,
The protrusion is disposed between the first large diameter portion and the second large diameter portion in a direction around the rotation axis of the drive shaft,
The main cam control chamber is provided in a region between the first large diameter portion and the protrusion, and pressure upstream from the metering orifice is introduced into the main cam control chamber,
The housing is a downstream pressure introduction passage that opens into a sub cam control chamber that is a space between the second large diameter portion and the protrusion, and pressure downstream from the metering orifice is introduced. A variable displacement pump having the downstream pressure introduction passage. The variable displacement pump according to claim 13,
A variable displacement pump in which a direction in which the cam ring rotates in a direction in which the volume of the sub cam control chamber decreases and a rotation direction of the drive shaft coincide with each other. The variable displacement pump according to claim 14,
The control valve is a variable displacement pump that holds the position of the cam ring by controlling the pressure in the main cam control chamber. The variable displacement pump according to claim 14,
The variable displacement pump is
The ratio of the decrease amount of the volume of the plurality of pump chambers in the first discharge region and the second discharge region to the increase amount of the volume of the plurality of pump chambers in the first suction region and the second suction region becomes small. A variable displacement pump having an elastic member that biases the cam ring in a direction in which the cam ring rotates. The variable displacement pump according to claim 1, wherein
The housing has an annular adapter ring portion surrounding the cam ring,
The adapter ring part has a bearing holding part,
The bearing holding portion is formed in a region where the bearing is provided in the adapter ring portion,
With respect to the inner diameter of the adapter ring portion, which is the distance from the rotation axis of the drive shaft to the inner peripheral surface of the adapter ring portion, the bearing is more than the region in which the first seal member is in sliding contact with the inner peripheral surface of the adapter ring portion. The variable displacement pump in which the region where the bearing is provided is formed in the adapter ring portion so that the region where the is provided is larger. The variable displacement pump according to claim 1, wherein
The variable displacement pump is
A projecting portion provided in the housing, the projecting portion projecting inward in the radial direction of the rotation axis of the drive shaft;
The cam ring is
A small-diameter portion having an outer diameter that is a distance from the rotation axis of the drive shaft to the outer peripheral edge of the cam ring, the first outer diameter;
A first large-diameter portion that is a pair of large-diameter portions provided on both sides of the small-diameter portion in a direction around the rotation axis of the drive shaft and having a second outer diameter that is larger than the first outer diameter; A second large diameter portion,
The protrusion is disposed between the first large diameter portion and the second large diameter portion in a direction around the rotation axis of the drive shaft,
The main cam control chamber is provided in a region between the first large diameter portion and the protruding portion,
A variable displacement pump in which a direction in which the cam ring rotates in a direction in which the volume of the main cam control chamber decreases and a rotation direction of the drive shaft coincide with each other.

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