JP4624955B2 - Variable displacement vane pump - Google Patents

Description

The present invention relates to a variable displacement pump, and more particularly to a variable displacement vane pump for power steering.

Conventionally, in the variable displacement vane pump described in Patent Document 1, the pump discharge amount is controlled by swinging the cam ring.
JP-A-11-93856

However, in the above prior art, this pump has one suction port and one discharge port, unlike the fixed displacement type, so that the pressure on the discharge port side is unilaterally large. The pressure on the discharge port side acts on the rotor and the drive shaft, and the drive shaft is offset and deformed to the suction port side. Along with this deformation, there is a problem that the relative position between the drive shaft and the cam ring is deviated, so that the compression start timing is delayed, resulting in a decrease in pump efficiency and vibration.

The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a variable displacement vane pump in which a reduction in pump efficiency and vibration associated with an offset deformation of a drive shaft are reduced.

In order to achieve the above object, according to the present invention, a pump body, a drive shaft pivotally supported by the pump body, a rotor provided in the pump body and driven to rotate by the drive shaft, and a circumference of the rotor A plurality of pumps together with the rotor and the vanes on the inner peripheral side, the vanes disposed in a plurality of slots in the direction so as to be freely retractable, and provided on the support surface of the pump body in the pump body. A cam ring that changes the amount of eccentricity with respect to the rotor by rolling the support surface, a first member and a second member provided on both sides in the axial direction of the cam ring, and the first member or the second member. provided on at least one side of the member, a suction port which opens into the suction region the volume of the plurality of pump chambers increases, the volume of the plurality of pump chambers is reduced A discharge port which opens into the discharge region that is provided on the outer peripheral side of the cam ring, a first fluid pressure chamber provided in the direction of the outer peripheral side space of the cam ring pump discharge amount increases, the pump discharge amount decreases A variable displacement vane pump provided with a seal member that is separated from a second fluid pressure chamber provided in a direction, wherein the center of the cam ring is the suction region and the discharge region with respect to the drive shaft and the rotor. The drive shaft is located closer to the suction port than the center of the drive shaft in a no-load state where no differential pressure acts, and the drive shaft is elastically deformed toward the suction port due to the differential pressure acting It was decided to be provided so as to be located on the discharge port side with respect to the center .

Therefore, it is possible to provide a variable displacement vane pump in which a decrease in pump efficiency and vibration due to offset deformation of the drive shaft are reduced.

Hereinafter, the best mode for realizing the variable displacement vane pump of the present invention will be described based on the embodiments shown in the drawings.

[Outline of vane pump]
Example 1 will be described with reference to FIGS. FIG. 1 is an axial sectional view of the vane pump 1, and FIGS. 2 and 3 are radial sectional views. FIG. 2 shows the case where the cam ring 4 is positioned in the most negative y-axis direction (maximum eccentricity), and FIG. 3 shows the case where the cam ring 4 is positioned in the most positive y-axis direction (minimum eccentricity).

The axial direction of the drive shaft 2 is the x-axis, and the direction in which the drive shaft is inserted into the first and second housings 11 and 12 is the positive direction. Further, the axial direction of the spring 201 (see FIG. 2) that restricts the swing of the cam ring 4 and the direction in which the cam ring 4 is urged is the y-axis negative direction, the axis orthogonal to the x and y axes, and the intake port IN. The side is the z-axis positive direction.

The vane pump 1 includes a drive shaft 2, a rotor 3, a cam ring 4, an adapter ring 5, and a pump body 10. The drive shaft 2 is connected to the engine via a pulley and rotates integrally with the rotor 3.

A plurality of slots 31, which are axial grooves, are formed radially on the outer periphery of the rotor 3, and vanes 32 are inserted into the slots 31 so as to be able to protrude and retract in the radial direction. Further, a back pressure chamber 33 is provided at an inner diameter side end portion of each slot 31, and pressure oil is supplied to urge the vane 32 radially outward.

The pump body 10 is formed of a first housing 11 and a second housing 12 (second member). The first housing 11 has a bottomed cup shape that opens to the positive side of the x-axis, and a disk-shaped side plate 6 (first member) is accommodated on the bottom 111. The adapter ring 5, the cam ring 4, and the rotor 3 are housed on the pump element accommodating portion 112 that is the inner peripheral portion of the first housing 11 and on the side of the side plate 6 in the positive x-axis direction.

The second housing 12 is in liquid-tight contact with the adapter ring 5, the cam ring 4, and the rotor 3 from the x axis positive direction side, and the adapter ring 5, the cam ring 4, and the rotor 3 are sandwiched between the side plate 6 and the second housing 12. The Rukoto.

Suction ports 62 and 121 and discharge ports 63 and 122 are provided on the x-axis positive side surface 61 of the side plate 6 and the x-axis negative direction side surface 120 of the second housing 12, respectively, and are connected to the suction port IN and the discharge port OUT. The hydraulic oil is supplied to and discharged from the pump chamber B formed between the rotor 3 and the cam ring 4.

The adapter ring 5 is a substantially elliptical annular member having a major axis on the y-axis side and a minor axis on the z-axis side. The adapter ring 5 is accommodated in the first housing 11 on the outer peripheral side and the cam ring 4 on the inner peripheral side. To dispose. The adapter ring 5 is restricted from rotating with respect to the first housing 11 by the pin 40 so as not to rotate in the first housing 11 when the pump is driven.

The cam ring 4 is a substantially perfect circular ring member, and the outer periphery thereof is provided with substantially the same diameter as the short axis of the adapter ring 5. Therefore, by being accommodated in the substantially elliptical adapter ring 5, a fluid pressure chamber A is formed between the inner periphery of the adapter ring 5 and the outer periphery of the cam ring 4, and the cam ring 4 extends in the y-axis direction within the adapter ring 5. It can swing.

Further, a seal member 50 (first seal member) is provided at the end of the adapter ring inner peripheral surface 53 in the z-axis positive direction, and a support surface N is formed at the end of the z-axis negative direction. The adapter ring 5 locks the cam ring 4 in the negative z-axis direction on the support surface N.

A pin 40 (second seal member) is provided on the support surface N, and the fluid pressure chamber A between the cam ring 4 and the adapter ring 5 is defined by the pin 40 and the seal member 50 in the y-axis negative and positive directions. Thus, the first and second fluid pressure chambers A1 and A2 are formed.

Here, since the cam ring 4 swings while rolling on the support surface N, the volumes of the fluid pressure chambers A1 and A2 change. However, the z-axis negative direction support surface N rotates counterclockwise around the y axis as the center. Parallel to the ξ axis rotated in the direction. That is, the support surface N is inclined to the z-axis positive direction side as it goes to the y-axis positive direction side, and the cam ring 4 is easily swung in the y-axis negative direction by the inclined support surface N.

By introducing the suction pressure into the second fluid pressure chamber A2, the cam ring 4 support force due to the internal pressure of the second fluid pressure chamber A2 cannot be obtained sufficiently, so that the cam ring 4 is in the second fluid pressure chamber A2 side (in the positive y-axis direction). However, the cam ring 4 can be tilted by providing the support position in the high rotation low pressure state on the support surface N higher than the support position in the low rotation high pressure state (closer to the suction ports 62 and 121). To prevent.

The outer diameter of the rotor 3 is provided smaller than the inner diameter 41 of the cam ring, and is accommodated on the inner peripheral side of the cam ring 4. Even when the cam ring 4 swings and the relative position of the rotor 3 and the cam ring 4 changes, the outer periphery of the rotor 3 is provided so as not to contact the inner periphery 41 of the cam ring.

Further, when the cam ring 4 is positioned most in the y-axis negative direction due to swinging, the distance L between the cam ring inner periphery 41 and the rotor 3 outer periphery is maximum on the y-axis negative direction side. When the cam ring 4 is positioned most in the y-axis positive direction, the distance L is similarly minimum on the y-axis positive direction side.

The radial length of the vane 32 is larger than the maximum value of the distance L. Therefore, the vane 32 is always inserted into the slot 31 regardless of the relative position between the cam ring 4 and the rotor 3, and the cam ring inner periphery 41. It will maintain the state contact | abutted to. As a result, the vane 32 constantly receives the back pressure from the back pressure chamber 33 and comes into liquid tight contact with the cam ring inner periphery 41.

Therefore, the region between the cam ring 4 and the rotor 3 is always liquid-tightly defined by the adjacent vanes 32 to form the pump chamber B. If the rotor 3 and the cam ring 4 are in an eccentric state due to the swing, the volume of each pump chamber B changes as the rotor 3 rotates.

The suction ports 62 and 121 and the discharge ports 63 and 122 provided in the side plate 6 and the second housing 12 are provided along the outer periphery of the rotor 3, and supply and discharge of hydraulic oil is performed by changing the volume of each pump chamber B. Is called.

A radial through hole 51 is provided at the y-axis positive end of the adapter ring 5. Further, a plug member insertion hole 114 is provided at the end of the first housing 11 in the positive direction of the y axis, and a bottomed cup-shaped plug member 70 is inserted so as to be liquidtight with the outside of the first and second housings 11 and 12. Keep.

A spring 201 is inserted into the inner periphery of the plug member 70 so as to be expandable and contractible in the y-axis direction, passes through the radial through hole 51 of the adapter ring 5 and abuts on the cam ring 4 and biases in the negative y-axis direction.

The spring 201 urges the cam ring 4 in the direction in which the swing amount becomes maximum, and stabilizes the discharge amount (cam ring 4 swing position) at the time of pump start when the pressure is not stable.

In this embodiment, the opening in the radial direction through hole 51 of the adapter ring 5 is used as a stopper for the cam ring 4 to restrict the swing in the positive y-axis direction. It is good also as a stopper by making it protrude to the inner peripheral side of the ring 5.

[Supply of pressure oil to the first and second fluid pressure chambers]
A through hole 52 is provided on the z-axis positive direction side of the adapter ring 5 and on the y-axis negative direction side of the seal member 50. Each of the through holes 52 communicates with the control valve 7 via an oil passage 113 provided in the first housing 11, and connects the first fluid pressure chamber A <b> 1 and the control valve 7 on the y axis negative direction side. The oil passage 113 opens into a valve housing hole 115 that accommodates the control valve 7, and the control pressure Pv is introduced into the first fluid pressure chamber A1 as the pump is driven.

By providing the through hole 52 provided in the adapter ring 5 in the center of the axial width of the adapter ring 5, the outer peripheral surface of the adapter ring 5 becomes a sealing surface to reduce leakage.

The control valve 7 is connected to the discharge ports 63 and 122 via the oil passages 21 and 22. An orifice 8 is provided on the oil passage 22, and a discharge pressure Pout that is an upstream pressure of the orifice 8 and a downstream pressure Pfb of the orifice 8 are introduced into the control valve 7. The control valve 7 is driven by the differential pressure between Pout and Pfb and the valve spring 7a to generate a control pressure Pv.

Therefore, the control pressure Pv is introduced into the first fluid pressure chamber A1, and this control pressure Pv is generated based on the suction pressure Pin and the discharge pressure Pout, so that the control pressure Pv ≧ the suction pressure Pin.

On the other hand, the suction pressure Pin is introduced into the second fluid pressure chamber A2 via the communication path 64. The communication passage 64 communicates the inlet port IN and the negative x-axis direction side face 120 in the second housing 1 2, a fluid passage connecting the inlet port IN and the second fluid pressure chamber A2, the rocking of the cam ring 4 The second fluid pressure chamber A2 always opens regardless of the moving position.

Therefore, the suction pressure Pin is always introduced into the second fluid pressure chamber A2, and thereby the vane pump 1 controls only the fluid pressure P1 in the first fluid pressure chamber A1. On the other hand, the hydraulic pressure P2 in the second fluid pressure chamber A2 is not controlled and always P2 = suction pressure Pin. As a result, pressure leakage from the second fluid pressure chamber A2 side to the suction ports 63 and 122 side is reduced, and a reduction in pump efficiency is suppressed.

[Swing of cam ring]
The biasing force in the y-axis positive direction that the cam ring 4 receives from the pressure P1 of the first fluid pressure chamber A1 can be larger than the sum of the hydraulic pressure P2 of the second fluid pressure chamber A2 and the biasing force in the negative y-axis direction received from the spring 201. For example, the cam ring 4 swings in the positive y-axis direction with the pin 40 as the rotation center. By swinging, the volume of the pump chamber By + on the positive side in the y-axis increases, and the volume of the pump chamber By− on the negative side in the y-axis decreases.

When the volume of the pump chamber By− on the negative y-axis side decreases, the amount of oil supplied from the suction ports 62 and 121 to the discharge ports 63 and 122 per unit time decreases, and the discharge pressure decreases. Along with this, the pressure P1 of the first fluid pressure chamber A1 into which the discharge pressure has been introduced also decreases, and if the sum of the urging forces in the negative y-axis direction cannot be fully resisted, the cam ring 4 swings in the negative y-axis direction. Move.

When the urging forces in the positive and negative directions of the y axis become substantially equal, the forces in the y axis direction acting on the cam ring 4 are balanced and the cam ring 4 stops. When the discharge pressure increases, the cam ring 4 swings in the y-axis positive direction and becomes the same axis as the rotor 3, and the volumes of the pump chambers By + and By- on the y-axis positive and negative directions become equal and the suction pressure = The discharge pressure = 0.

Along with this, the pressure P1 of the first fluid pressure chamber A1 also becomes 0, and the cam ring 4 is urged in the y-axis negative direction by the urging force F of the spring 201. In this way, the amount of eccentricity of the cam ring 4 is adjusted so that the discharge pressure P1 returns and the differential pressure across the discharge orifice becomes constant.

[Position shift between drive shaft center and cam ring center]
FIG. 4 is a partial cross-sectional view of the vane pump 1 in a no-load state (pump non-drive state). The center of the drive shaft 2 and the rotor 3 is OR, and the center of the cam ring 4 is Oc.

In the present embodiment, the cam ring center Oc in the no-load state is positioned closer to the suction ports 62 and 121 (z-axis positive direction side) than the center OR of the drive shaft 2. The rotor 3 is urged by the discharge pressure from the z-axis negative direction side, and the drive shaft 2 is bent and deformed to the z-axis positive direction side by this urging force.

Therefore, since the center OR of the drive shaft 2 is shifted in the z-axis positive direction, the center Oc of the cam ring 4 is offset in advance to the z-axis positive direction side with respect to the drive shaft center OR. Specifically, the position of the cam ring 4 in the z-axis direction is increased by inclining the support surface N. Thereby, even when the drive shaft 2 is bent by the discharge pressure when the pump is driven, a stable discharge amount is obtained (details will be described later).

Since the cam ring inner periphery 41 and the outer periphery of the rotor 3 are both substantially circular, the distance L between the cam ring inner periphery 41 and the outer periphery of the rotor 3 is uniformly equal over the entire periphery when the cam ring center Oc and the rotor center OR coincide. Become.

If the center Oc of the cam ring 4 is deviated from the center OR of the rotor 3 and the drive shaft 2, the distance L between the cam ring inner periphery 41 and the outer periphery of the rotor 3 is not uniform, and the maximum and minimum values on the Oc-OR straight line. Takes a value.

Since the vane 32 is urged in the outer diameter direction by the pressure from the back pressure chamber 33, the amount of protrusion of the vane 32 changes as the distance L changes. Therefore, the volume of the pump chamber B separated by the outer periphery of the rotor 3, the inner periphery 41 of the cam ring, and the vane 32 also changes with the distance L.

That is, the rotor 3 outer circumference and the larger volume of the pump chamber B is the distance L is large the position of the cam ring inner circumference 41, the distance L is the volume of the pump chamber B is small for small position. Accordingly, as the rotor 3 rotates, the volume of the pump chamber B changes from expansion to reduction before and after the distance L reaches the maximum value Lmax (on the negative side of the y-axis on the Oc-OR straight line) on the Oc-OR straight line. Before and after the distance L (on the Y-axis positive direction side on the Oc-OR straight line) reaches the minimum value Lmin on the OR straight line, the pump chamber B changes from shrinking to enlarging.

Since the rotor 3 is rotating counterclockwise, eleven one pump chamber B a of the pump chamber B is when crossing the Oc-OR linearly in the y-axis negative side, z axis positive than Oc-OR linear On the direction side, the volume of the pump chamber Ba is enlarged, but when the pump chamber Ba is located on the Oc-OR straight line, the volume fluctuation becomes zero, and the position is on the z-axis negative direction side across the Oc-OR straight line. Then it starts to shrink.

That is, every time the pump chamber B a straddles the Oc-OR linearly in the y-axis negative direction side, the volume of the pump chamber Ba is turn to shrink from expanding. Similarly, each time the pump chamber B a straddles the Oc-OR linearly in the y-axis positive direction, the volume of the pump chamber Ba is turn to expand from the reduced. Thus, the pump chamber B is the time to cross the Oc-OR straight line, so that the positive and negative volume change of the pump chamber B are switched.

[Port reference line]
Pump chamber B switches the suction / discharge between the intake ports 62, 121 and the discharge port 63, 122, the position of the pump chamber B at the time switched to the first, second reference position M1, M2. The first reference position M1 is on the y-axis negative direction side, and the second reference position M2 is on the y-axis positive direction side.

In the first embodiment, the interval between adjacent vanes in the vane 32 is set to one pitch, and the first reference position M1 is advanced by a half pitch from the terminal ends 62a and 121a of the suction ports 62 and 121 (end portions on the rotation direction side of the rotor 3). It is a position. Similarly, the second reference position M2 terminate 63a of the discharge port 63, 122, from 122a (rotation direction side end portion of the rotor 3) and a position advanced by half a pitch.

The M1-M2 line formed from M1 and M2 is defined as a port reference line M1-M2. Thus in the first embodiment, the pump chamber B a is the suction / discharge of the pump chamber Ba each time through this port reference line M1-M2 is switched.

For this reason, the z-axis positive direction region Bz + on the z-axis positive direction side (the suction ports 62 and 121 side) from the port reference line M1-M2 is the suction region and the z-axis negative direction side (the discharge ports 63 and 122 side). The z-axis negative direction side region Bz− is a discharge region.

Therefore, in order to stabilize the discharge of the vane pump 1, it is desirable that the Oc-OR line where the volume fluctuation of the pump chamber B is switched and the port reference line M1-M2 where the suction / discharge of the pump chamber B is switched as close as possible. . In particular, since the discharge amount is stable when close to each other at the first reference position M1 where the suction is switched to the discharge, it is desirable that the Oc-OR line and the port reference line M1-M2 be as close and parallel as possible.

[Relationship between port reference line and Oc-OR line]
5 and 6 are schematic diagrams showing the relationship between the port reference line M1-M2 and the Oc-OR line. 5 shows a conventional example (the position of the center Oc of the cam ring 4 and the center OR of the drive shaft 2 in the no-load state (pump non-drive state)), and FIG. 6 shows the first embodiment of the present application (the cam ring center Oc in the no-load state). (When located on the positive z-axis direction side of the port reference line M1-M2).

In the figure, the thick solid line is the port reference line M1-M2, the thick one-dot chain line is the Oc-OR line when the pump is high pressure, and the thick broken line is the Oc-OR line when the pump is low pressure.

As the cam ring 4 swings, the cam ring center Oc moves in the y-axis direction, and is largely offset toward the negative y-axis side with respect to the drive shaft center OR when there is no load and at the maximum eccentricity at low speed (see FIG. 2). is doing. On the other hand, at the high speed, the eccentric amount of the cam ring 4 is small and the offset amount of the cam ring center Oc is small, but still remains offset with respect to the drive shaft center OR.

Here, when the pump 1 is driven and pressure is generated in the pump chamber B, the pump chamber B has a high pressure in the z-axis negative direction region Bz− across the port reference line M1-M2, and a low pressure in the z-axis positive direction region Bz +. Thus, a differential pressure is generated.

Due to this differential pressure, the rotor 3 is urged together with the drive shaft 2 in the positive z-axis direction, and the drive shaft 2 is elastically deformed in the positive z-axis direction. As a result, the center OR of the drive shaft 2 also moves in the positive z-axis direction, and a deviation occurs between the cam ring center Oc and the drive shaft center OR. The deviation is large at high pressure and small at low pressure.

Therefore, due to the elastic deformation of the drive shaft 2 due to the discharge pressure, the Oc-OR line at high pressure and low pressure is greatly inclined with respect to the port reference line M1-M2, and the port reference line M1- at high pressure and low pressure. The angles of the Oc-OR line with respect to M2 are α ′ and β ′. Since α ′ and β ′ are both large, the Oc-OR line and the port reference line M1-M2 are separated from each other at the first and second reference positions M1 and M2 where the suction / discharge is switched, and the discharge is not stable.

On the other hand, in Embodiment 1 of the present application, the cam ring center Oc is offset in advance to the z-axis positive direction side (the suction ports 62 and 121 side) from the drive shaft center OR. Therefore, even when the drive shaft 2 is bent by the discharge pressure and the drive shaft center OR is moved in the positive z-axis direction, the Oc-OR line is not greatly inclined with respect to the port reference line M1-M2.

As a result, the angle α between the Oc-OR line and the port reference line M1-M2 at the time of driving the pump is smaller than the angle α ′ of the conventional example (α <α ′) and closer to parallel, and suction is performed at high pressure. / Close to the Oc-OR line and the port reference line M1-M2 at the first and second reference positions M1, M2 at which the discharge is switched. Therefore, the discharge amount fluctuation at the time of switching between suction and discharge becomes small, and discharge is stabilized.

[Effect of Example 1]
(1) A pump body 10, a drive shaft 2 that is pivotally supported by the pump body 10, a rotor 3 that is provided in the pump body 10 and is driven to rotate by the drive shaft 2, and a plurality of them are provided in the circumferential direction of the rotor 3. The vane 32 accommodated in the slot 31 so as to be freely retractable and swingably provided on the support surface N of the pump body 10 in the pump body 10, and together with the rotor 3 and the vane 32 on the inner periphery 41 side. A cam ring 4 forming a plurality of pump chambers B, a side plate 6 and a second housing 12 provided on both sides of the cam ring 4 in the x-axis direction, and provided on at least one side of the side plate 6 or the second housing 12, Suction ports 62 and 121 that open to areas where the volumes of the plurality of pump chambers B increase, and discharge ports 63 that open to areas where the volumes of the plurality of pump chambers B decrease, 22 and the first fluid pressure chamber A1 provided on the outer peripheral side of the cam ring 4 and the outer peripheral side space (fluid pressure chamber) A of the cam ring 4 in the direction in which the pump discharge amount increases, and the pump discharge amount decreases. In the variable displacement vane pump 1 including the seal member 50 that is separated from the second fluid pressure chamber A2 provided in the direction of the center, the center Oc of the cam ring 4 is more than the center OR of the drive shaft 2 when no load is applied. The suction ports 62 and 121 (z-axis positive direction side) are offset.

As a result, the variation in the discharge amount at the time of switching between suction and discharge at high pressure is reduced, and the discharge can be stabilized and the decrease in pump efficiency and vibration can be suppressed.

(3) Among the vanes 32, the interval between the adjacent vanes 32 is one pitch, and the center Oc of the cam ring 4 is the rotational direction of the rotor 3 from the end of the suction ports 62 and 121 (counterclockwise in FIGS. 2 to 6). Direction) and an offset arrangement closer to the suction ports 62 and 121 than the port reference line M1-M2 connecting the end of the discharge ports 63 and 122 and the position advanced by a half pitch in the rotation direction of the rotor 3. It was decided to be done.

As a result, the angle between the Oc-OR line and the port reference line M1-M2 during driving of the pump is smaller than that of the conventional example and becomes more parallel, and at the first and second reference positions M1, M2 where the suction / discharge is switched. The Oc-OR line is close to the port reference line M1-M2. Therefore, the fluctuation of the discharge amount at the time of switching between suction and discharge is reduced, so that the discharge can be stabilized and the reduction in pump efficiency and vibration can be suppressed.

Hereinafter, modifications of the first embodiment will be described.
[Example 1-1]
FIG. 7 shows an example in which the definition of the port reference line is changed. In the first embodiment, the first and second reference positions M1 and M2 at which the suction / discharge is switched and the drive shaft center OR are positioned on a straight line. However, the embodiment 1-1 shows a case where the suction / discharge is not positioned on the straight line.

(2) The center Oc of the cam ring 4 is the center OR of the drive shaft 2 in the no-load state, the first reference position M1 advanced by a half pitch from the terminal ends 62a, 121a of the suction ports 62, 121, or the discharge ports 63, 122. The suction ports 62 and 121 are offset from the port reference line M1-M2 connecting the second reference position M2 advanced by a half pitch from the terminal ends 63a and 122a.

Thereby, the same effect as Example 1 can be acquired. In Example 1-1, since the M1-OR-M2 line is a broken line, the port reference line is the M1-OR line or the M2-OR line. By appropriately changing the definition of the port reference line according to the characteristics of the vane pump 1, optimum discharge performance can be obtained. The broken line M1-OR-M2 may be used as the port reference line as it is.

[Other embodiments]
The best mode for carrying out the present invention has been described based on each embodiment, but the specific configuration of the present invention is not limited to each embodiment and does not depart from the gist of the invention. Such design changes are included in the present invention.

It is an axial sectional view of a vane pump in Example 1. It is radial direction sectional drawing (at the time of the largest rocking | fluctuation) of the vane pump in Example 1. FIG. It is radial direction sectional drawing (at the time of the minimum rocking | fluctuation) of the vane pump in Example 1. FIG. It is a fragmentary sectional view of the vane pump in a no-load state (pump non-drive state). It is a schematic diagram which shows the relationship between the port reference line M1-M2 and Oc-OR line in a prior art example. It is a schematic diagram which shows the relationship between the port reference line M1-M2 and Oc-OR line in Example 1 of this application. It is a fragmentary sectional view of the vane pump in Example 1-1.

1 Variable displacement vane pump
2 Drive shaft
3 Rotor
4 Cam ring
5 Adapter ring
6 Side plate
7 Control valve
7a Valve spring
8 Orifice
10 Pump body
11, 12 First and second housing
21, 22 Oil passage
31 slots
32 Vane
33 Back pressure chamber
40 pins
41 Cam ring inner circumference
50 Seal member
51 radial through hole
52 Through hole
53 Adapter ring inner circumference
61 x-axis positive side
62,121 Suction port
62a, 121a Termination
63,122 Discharge port
63a, 122a Termination
64 communication paths
70 Plug member
111 Bottom
112 Pump element housing
113 Oilway
114 Plug member insertion hole
115 Valve housing hole
120 x-axis negative side
201 Spring
A Fluid pressure chamber
A1, A2 First and second fluid pressure chambers
A2 Fluid pressure chamber
B Pump room
Bz + z-axis positive direction side area
Bz- z-axis negative direction area
IN inlet
M1, M2 first and second reference positions
N Support surface
Na Rolling support point
Oc Cam ring center
OR rotor center
OUT outlet
M1-M2 port reference line

Claims (2)

A pump body;
A drive shaft supported by the pump body;
A rotor provided in the pump body and driven to rotate by the drive shaft;
Vanes accommodated in a plurality of slots provided in the circumferential direction of the rotor so as to be able to appear and retract,
The pump body is provided on a support surface of the pump body, and a plurality of pump chambers are formed on the inner peripheral side together with the rotor and the vane, and the eccentric amount with respect to the rotor is reduced by rolling the support surface. Changing cam ring,
A first member and a second member provided on both axial sides of the cam ring;
A suction port provided on at least one side of the first member or the second member and opening to a suction region where the volumes of the plurality of pump chambers increase, and opening to a discharge region where the volumes of the plurality of pump chambers are reduced A discharge port,
A first fluid pressure chamber provided on the outer peripheral side of the cam ring and provided in a direction in which the pump discharge amount increases in the outer peripheral side space of the cam ring, and a second fluid pressure chamber provided in a direction in which the pump discharge amount decreases. A sealing member that is separated into
In a variable displacement vane pump comprising:
The center of the cam ring is
Located on the suction port side from the center of the drive shaft in a no-load state where the differential pressure between the suction region and the discharge region does not act on the drive shaft and the rotor ,
The variable displacement vane pump is provided so as to be positioned closer to the discharge port than the center of the drive shaft in a state where the drive shaft is elastically deformed toward the suction port due to the differential pressure acting . A pump body;
A drive shaft supported by the pump body;
A rotor provided in the pump body and driven to rotate by the drive shaft;
Vanes accommodated in a plurality of slots provided in the circumferential direction of the rotor so as to be able to appear and retract,
The pump body is provided on a support surface of the pump body, and a plurality of pump chambers are formed on the inner peripheral side together with the rotor and the vane, and the eccentric amount with respect to the rotor is reduced by rolling the support surface. Changing cam ring,
A first member and a second member provided on both axial sides of the cam ring;
A suction port provided on at least one side of the first member or the second member and opening to a suction region where the volumes of the plurality of pump chambers increase, and opening to a discharge region where the volumes of the plurality of pump chambers are reduced A discharge port,
A first fluid pressure chamber provided on the outer peripheral side of the cam ring and provided in a direction in which the pump discharge amount increases in the outer peripheral side space of the cam ring, and a second fluid pressure chamber provided in a direction in which the pump discharge amount decreases. A sealing member that is separated into
In a variable displacement vane pump comprising :
The center of the cam ring when the amount of eccentricity with respect to the rotor is minimum ,
Located on the suction port side from the center of the drive shaft in a no-load state where the differential pressure between the suction region and the discharge region does not act on the drive shaft and the rotor ,
The variable displacement vane pump is provided so as to be positioned closer to the discharge port than the center of the drive shaft in a state where the drive shaft is elastically deformed toward the suction port due to the differential pressure acting .

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