JP2020041438A - Pump device - Google Patents

Abstract

To provide a pump device capable of suppressing a local wear at a tip end of a vane.SOLUTION: In a variable capacity vane pump 1, a cam profile of a cam ring 8 has a deflection area deflected outward in a diametrical direction about a rotation axis O of a driving shaft 6 with respect to a perfect circle cam profile in a suction area 21. In the suction area 21, a sliding range at a tip end of a vane 16 contacting with an inner peripheral edge of the cam ring 8 changes according to a phase, so that a local wear at a tip end of the vane 16 is suppressed. Consequently, galling and seizure between the tip end of the vane 16 and the inner peripheral edge of the cam ring 8 are suppressed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pump device.

  Patent Literature 1 discloses a variable displacement vane pump in which a vane is retractably housed in a slit of a rotor and changes the volume of a pump chamber formed between an inner peripheral edge of a cam ring, an outer peripheral edge of the rotor, and the vane. . The vane is urged in a direction protruding from the slit by the pressure of the hydraulic oil introduced into the back pressure chamber of the rotor.

JP 2013-194677 A

However, in the prior art, in the suction region where the pressure in the pump chamber is lower than the pressure in the back pressure chamber, the tip of the vane is pressed against the inner peripheral edge of the cam ring, causing local wear of the tip of the vane. Is promoted. Due to the local wear, the oil film breaks due to a decrease in the viscosity of the hydraulic oil interposed between the vane and the cam ring, and galling and seizure may occur due to the contact between the metals.
An object of the present invention is to provide a pump device capable of suppressing local wear of the vane tip.

  In one embodiment of the invention, in the pump, the cam profile of the cam ring has, in the suction area, a deviated area deviated outwardly or inwardly in the radial direction with respect to the axis of rotation of the drive shaft relative to the round cam profile.

  Therefore, in the suction area, the sliding range of the tip of the vane in contact with the inner peripheral edge of the cam ring changes depending on the phase, so that local wear of the tip of the vane is suppressed. As a result, galling and seizure between the tip of the vane and the inner peripheral edge of the cam ring can be suppressed.

FIG. 2 is an axial sectional view showing the variable displacement vane pump 1 according to the first embodiment. FIG. 2 is a sectional view taken along arrow S2-S2 in FIG. FIG. 3 is a rear view of the cam ring 8 according to the first embodiment. FIG. 4 is a diagram illustrating a cam profile radius change rate with respect to a cam profile angle in the first embodiment. FIG. 6 is a diagram illustrating a cam profile radius change rate with respect to a cam profile angle when the cam ring is deformed in the first embodiment. FIG. 3 is a diagram illustrating a tip shape of a vane 16 according to the first embodiment. FIG. 4 is a view showing a contact area between a vane tip curved surface portion 16a and an inner peripheral edge 8a of a cam ring 8 according to the first embodiment. FIG. 4 is a diagram illustrating a vane contact position with respect to a pump rotation angle according to the first embodiment. It is a figure which shows the cam profile radius change rate with respect to the cam profile angle when a cam profile is deviated radially inside rather than a perfect circular cam profile. FIG. 3 is a diagram illustrating an effect of expanding a vane contact range according to the first embodiment. FIG. 7 is a view showing a relationship between a rotation axis O of a drive shaft 6 and a center P of an inner peripheral edge 8a of a cam ring 8 in a variable displacement vane pump (pump device) 1 according to a second embodiment.

[Embodiment 1]
FIG. 1 is an axial sectional view showing a variable displacement vane pump (pump device) 1 according to Embodiment 1, and FIG. 2 is a sectional view taken along the line S2-S2 in FIG.
The variable displacement vane pump 1 has a pump housing 4 and a pump element 5. The variable displacement vane pump 1 performs a pumping operation by rotating the pump element 5 with the drive shaft 6. The pump housing 4 is formed by abutting the front housing 2 and the rear housing 3. The pump housing 4 accommodates the pump element 5 in the pump element accommodation space 4a. The pump element 5 has a rotor 7 and a cam ring 8. The rotor 7 rotates integrally with the drive shaft 6. The cam ring 8 is located on the outer peripheral side of the rotor 7, and is formed in a substantially annular shape with a metal material. The cam ring 8 can swing in a direction in which the amount of eccentricity with respect to the rotor 7 changes. The pump housing 4 has an adapter ring 9 and a pressure plate 10. The adapter ring 9 is located on the outer peripheral side of the cam ring 8 and has a substantially annular shape. The adapter ring 9 is fixed to the outer peripheral cylindrical surface of the pump element housing space 4a. The pressure plate 10 is located on the inner bottom surface 2a of the front housing 2 in the pump element housing space 4a, and has a substantially disk shape.

  The relative rotation of the adapter ring 9 and the pressure plate 10 with respect to the pump housing 4 is restricted by the positioning pins 11. A plate member 12 is provided on the clockwise direction side in FIG. 2 of the positioning pin 11 (the first fluid pressure chamber 14a described later). The plate member 12 has a swing fulcrum function of the cam ring 8 and a sealing function of sealing between the cam ring 8 and the adapter ring 9. A seal member 13 that seals between the adapter ring 9 and the cam ring 8 is disposed at a position on the inner peripheral edge of the adapter ring 9 that faces the plate member 12 in the radial direction. The seal member 13 and the plate member 12 form a pair of fluid pressure chambers 14a and 14b between the cam ring 8 and the adapter ring 9. That is, the first fluid pressure chamber 14a is formed on one radial side of the cam ring 8, and the second fluid pressure chamber 14b is formed on the other radial side. When the cam ring 8 swings due to the pressure difference between the two fluid pressure chambers 14a and 14b, the amount of eccentricity of the center (axial center) P of the inner peripheral edge of the cam ring 8 with respect to the rotation axis O of the drive shaft 6 increases or decreases. The cam ring 8 is constantly urged by the return spring 15 in the direction in which the amount of eccentricity with the rotor 7 becomes maximum (the maximum eccentric side).

The rotor 7 has a plurality of slits 7a cut along the radial direction on the outer peripheral portion. The slits 7a are arranged at a constant pitch in the circumferential direction about the rotation axis O of the drive shaft 6. In each slit 7a, a vane 16 formed of a metal material in a substantially flat plate shape is accommodated so as to be able to protrude and retract in the radial direction of the rotor 7. A plurality of pump chambers 17 are formed by each vane 16 partitioning an annular space between the cam ring 8 and the rotor 7 in a circumferential direction. When the rotor 7 is driven to rotate counterclockwise in FIG. 2 by the drive shaft 6, each pump chamber 17 moves around while increasing or decreasing its volume, thereby performing a pump operation. Each vane 16 is pressed against the inner peripheral edge of the cam ring 8 by the pressure of hydraulic oil introduced into the back pressure chamber 7b formed on the inner peripheral side of each slit 7a.
On the inner side surface 3a of the rear housing 3 facing the pump element accommodating space 4a, a portion corresponding to a suction area where the volume of each pump chamber 17 gradually increases with the rotation of the rotor 7 is omitted in a front view along the circumferential direction. A first crescent-shaped first suction port 18 is formed. The first suction port 18 communicates with a suction passage 19a formed in the rear housing 3. As a result, the hydraulic oil introduced into the suction passage 19a via the suction pipe 20 connected to the reservoir tank (not shown) is sucked into each pump chamber 17 by the pump suction action in the suction area.

On the surface of the pressure plate 10 facing the rotor 7, a second suction port 21 having substantially the same shape as the first suction port 18 is formed at a position facing the first suction port 18. In the circumferential direction, a range from the start end 21a to the end 21b of the second suction port 21 is the suction area. The same applies to the first suction port 18. The second suction port 21 communicates with a return passage 22 formed in the front housing 2. The recirculation passage 22 communicates with a recess in the front housing 2 in which a seal member for sealing between the front housing 2 and the drive shaft 6 is accommodated. The surplus oil of the seal member is supplied to each pump chamber 17 by the pump suction action in the suction area, thereby preventing the surplus oil from leaking outside.
On the surface of the pressure plate 10 facing the rotor 7, a portion corresponding to a discharge region in which the volume of each pump chamber 17 gradually decreases with the rotation of the rotor 7, a substantially crescent-shaped first view along the circumferential direction. One discharge port 23 is formed. In the circumferential direction, a range from the start end 23a to the end 23b of the first discharge port 23 is a discharge region. The same applies to a second discharge port 25 described later. The first discharge port 23 communicates with the discharge passage 19b via a pressure chamber 24 formed in the inner bottom surface 2a of the front housing 2 facing the pressure plate 10. Thereby, the hydraulic oil discharged from each pump chamber 17 by the pump discharge action in the discharge area is discharged to the outside of the pump housing 4 through the pressure chamber 24 and the discharge passage 19b, and is supplied to the hydraulic power cylinder of the power steering device (not shown). Sent. The pressure plate 10 is pressed toward the rotor 7 by the pressure in the pressure chamber 24.
A second discharge port 25 having substantially the same shape as the first discharge port 23 is formed at a position facing the first discharge port 23 on the inner side surface 3a of the rear housing 3. By disposing the two suction ports 18 and 21 and the two discharge ports 23 and 25 symmetrically in the axial direction with the respective pump chambers 17 interposed therebetween, the pressure balance on both axial sides of the pump chambers 17 is maintained.

Inside the upper end of the front housing 2, a control valve 26 for controlling the pump discharge pressure is provided in a direction orthogonal to the drive shaft 6 (the left-right direction in FIG. 2). The control valve 26 is formed on the front housing 2 from left to right in FIG. The control valve 26 has a valve hole 28, a spool 29, and a control valve spring 30. The left opening of the valve hole 28 in FIG. The spool 29 is accommodated in the valve hole 28 slidably in the axial direction. The spool 29 is a spool valve having a substantially bottomed cylindrical shape. The control valve spring 30 biases the spool 29 toward the plug 27. The control valve spring 30 is a cylindrical compression coil spring.
In the valve hole 28, a high pressure chamber 28a, a medium pressure chamber 28b, and a low pressure chamber 28c are separated by a spool 29. The hydraulic pressure upstream of a not-shown metering orifice formed in the discharge passage 19b, that is, the hydraulic pressure of the pressure chamber 24 is introduced into the high-pressure chamber 28a. The intermediate pressure chamber 28b houses the control valve spring 30, and the hydraulic pressure downstream of the metering orifice is introduced. The low-pressure chamber 28c is formed on the outer peripheral side of the spool 29, and pump suction pressure is introduced from the suction passage 19a via the low-pressure passage 31.

  The spool 29 moves in the axial direction according to the pressure difference between the medium pressure chamber 28b and the high pressure chamber 28a. Specifically, when the pressure difference between the intermediate pressure chamber 28b and the high pressure chamber 28a is relatively small and the spool 29 is in contact with the plug 27, the communication between the first fluid pressure chamber 14a and the valve hole 28 is established. The communication passage 32 opens to the low pressure chamber 28c, and the relatively low oil pressure of the low pressure chamber 28c is introduced into the first fluid pressure chamber 14a. On the other hand, when the pressure difference between the intermediate pressure chamber 28b and the high pressure chamber 28a increases and the spool 29 moves in the axial direction against the urging force of the control valve spring 30, the pressure difference between the low pressure chamber 28c and the first fluid pressure chamber 14a is increased. The communication is gradually interrupted, and the high pressure chamber 28a communicates with the first fluid pressure chamber 14a via the communication passage 32. Thereby, the relatively high oil pressure of the high pressure chamber 28a is introduced into the first fluid pressure chamber 14a. That is, the hydraulic pressure of the low pressure chamber 28c or the high pressure chamber 28a is selectively introduced into the first fluid pressure chamber 14a.

The pump suction pressure is constantly introduced into the second fluid pressure chamber 14b. When the hydraulic pressure of the low pressure chamber 28c is introduced into the first fluid pressure chamber 14a, the cam ring 8 is located at a position (a left position in FIG. 2) where the amount of eccentricity with the rotor 7 is maximized by the urging force of the return spring 15. I do. At this time, the pump discharge amount becomes the maximum. On the other hand, when the hydraulic pressure of the high pressure chamber 28a is introduced into the first hydraulic pressure chamber 14a, the cam ring 8 is pressed against the urging force of the return spring 15 by the pressure of the first hydraulic pressure chamber 14a. And the amount of eccentricity between the cam ring 8 and the rotor 7 is reduced. As the eccentric amount decreases, the pump discharge amount decreases.
A relief valve 33 is formed inside the spool 29. The relief valve 33 maintains the closed state when the pressure in the intermediate pressure chamber 28b is lower than a predetermined value. The relief valve 33 is opened when the pressure in the medium pressure chamber 28b becomes higher than a predetermined pressure, that is, when the pressure on the power steering device side (load side) becomes higher than a predetermined pressure, and the relief valve 33 performs a relief operation. The operating oil is recirculated to the suction passage 19a via the low pressure passage 31 and the passage 28c. In other words, the relief valve 33 opens and closes the oil passage between the discharge passage 19b and the suction passage 19a.

FIG. 3 is a rear view of the cam ring 8 according to the first embodiment. FIG. 3 shows a state of maximum eccentricity (a state where the amount of eccentricity of the center (axial center) P of the inner peripheral edge of the cam ring 8 with respect to the rotation axis O is maximum).
In FIG. 3, it passes through a point p1 which is orthogonal to the rotation axis O and bisects a section between the end 23b of the first discharge port 23 and the start 21a of the second suction port 21 in the circumferential direction of the rotation axis O. The axis is defined as a first axis L1. An axis passing through a point p4 that is orthogonal to the first axis L1 and bisects a section between a pair of intersections p2 and p3 where the cam profile and the first axis L1 intersect is referred to as a second axis L2. An intersection point p4 between the first axis L1 and the second axis L2 is defined as a cam profile center point. An axis passing through the cam profile center point p4 and the end 21b of the second suction port 21 is defined as a third axis L3. The length between the point p5 where the third axis L3 and the cam profile intersect and the cam profile center point p4 is defined as a perfect circular cam profile radius r0. An arc centered on the cam profile center point p4 and having a perfect circular cam profile radius r0 is defined as a perfect circular cam profile. The cam profile of the first embodiment has a bias region deviated radially outward of the rotation axis O with respect to the perfect circular cam profile over the entire suction region at the time of maximum eccentricity. That is, in the cam ring 8 of the first embodiment, the cam profile is set such that the cam profile radius r at the time of maximum eccentricity is longer than the round cam profile radius r0 over the entire suction area. In the cam profile, a region of r longer than r0 is a deviation region.

  In FIG. 3, the change rate of the cam profile radius r with respect to the rotation direction (counterclockwise) of the drive shaft 6 is defined as a cam profile radius change rate [dr / dθ]. When the cam ring 8 is arranged so that the center P of the cam ring 8 coincides with the rotation axis O, the cam ring 8 passes through the inner peripheral edge 8a of the cam ring 8, that is, the center P of the cam profile and the start end 21a of the second suction port 21. A point on the suction area side of a pair of points intersecting with the straight line is defined as an angle 0 [deg] for defining a cam profile. Then, at each point of the inner peripheral edge 8a of the cam ring 8, the angle increases along the inner peripheral edge 8a toward the rotation direction of the drive shaft 6, and the cam profile definition is such that one inner peripheral edge becomes 360 [deg]. Angle (cam profile angle) θ is defined. FIG. 4 is a diagram showing a cam profile radius change rate with respect to a cam profile angle. At the time of maximum eccentricity, the sign of the cam profile radius change rate in the suction area is positive, and increases and decreases after increasing the cam profile angle θ. The sign of the change rate of the cam profile radius in the ejection region is minus, and decreases after increasing the cam profile angle θ, and then increases. That is, the cam profile radius r is longer than the perfect circular cam profile radius r0 over the entire suction area, and shorter than the perfect circular cam profile radius r0 over the entire discharge area. That is, the cam profile of the cam ring 8 in the suction area is bulged radially outward with respect to the perfect circle.

On the other hand, the cam profile radius change rate in the suction area at the time of the minimum eccentricity is smaller than that at the time of the maximum eccentricity. In the region of less than 2/3, the sign of the cam profile radius change rate remains positive. That is, the cam profile of the cam ring 8 has an offset region even when the cam ring 8 is at the minimum eccentricity.
FIG. 5 is a diagram illustrating a cam profile radius change rate with respect to a cam profile angle when the cam ring is deformed in the first embodiment. When the variable displacement vane pump 1 is operated (when the drive shaft 6 is rotating), the cam ring 8 reduces the cam profile radius change rate in the suction area due to the discharge pressure (internal pressure of the pump) acting on the discharge area. It is deformed in a direction in which the rate of change in radius increases. Here, the cam profile radius of the cam profile (the cam profile in the first state) when the variable displacement vane pump 1 is not operated (when the drive shaft 6 is stopped) is defined as a cam profile radius r1 in the first state. The cam profile radius (cam profile in the second state) when the variable displacement vane pump 1 is operated (when the drive shaft 6 rotates) is defined as a cam profile radius r2 in the second state. The maximum value of the absolute value of the difference between the cam profile radius r1 in the first state and the cam profile radius r2 in the second state at the same cam profile angle θ is defined as the first cam profile deviation amount Δr1. I do. The maximum value of the absolute value of the difference between the cam profile radius r1 in the first state and the perfect circular cam profile radius r0 at the same cam profile angle θ is defined as the second cam profile deviation amount Δr2. The cam ring 8 of the first embodiment has a cam profile in the first state,
Δr1 <Δr2
It has the following shape. In other words, even when the cam ring 8 is deformed by the pump internal pressure, the cam profile has a deviation region deviated radially outward from the perfect circular cam profile in the discharge region.

Next, the tip shape of the vane 16 will be described.
FIG. 6 is a diagram showing the tip shape of the vane 16.
The vane 16 has a vane tip curved surface portion 16a. The vane tip curved surface portion 16a has a circular arc shape that protrudes radially inward in a cross section perpendicular to the rotation axis O.
Here, assuming that the curvature radius of the vane tip curved surface portion 16a is rv (center of curvature p6), and the thickness (plate thickness) of the vane 16 in the circumferential direction with respect to the rotation axis O is T, the vane 16
2 × T ≦ rv
Having a shape satisfying
FIG. 7 is a view showing a contact area between the vane tip curved surface portion 16a and the inner peripheral edge 8a of the cam ring 8. As shown in FIG. In a section perpendicular to the rotation axis O, an axis orthogonal to the rotation axis O and passing through the center of the vane 16 in the circumferential direction is defined as a fourth axis L4. A line connecting the contact point p7 between the curved surface portion 16a of the vane tip and the inner peripheral edge 8a of the cam ring 8 and the center of curvature p6 is defined as a fifth axis L5. The contact angle δ changes in accordance with the phase (pump rotation angle) in the suction region where the inferior angle among the angles formed by the fourth axis L4 and the fifth axis L5 is the contact angle δ. The inner peripheral edge 8a of the cam ring 8 contacts the inner peripheral edge 8a within a range exceeding 40% (for example, 60%) of the outer peripheral edge length of the vane tip curved surface portion 16a.

Next, the operation and effect of the first embodiment will be described.
The cam profile of the cam ring 8 according to the first embodiment has, in the suction region, a bias region that is radially outwardly biased with respect to the perfect circular cam profile. That is, the cam profile in the suction area was set to a non-perfect circle (elliptical shape). Thereby, in the suction area, the sliding range of the vane tip curved surface portion 16a with the inner peripheral edge 8a of the cam ring 8 changes according to the phase, so that the local wear of the vane 16 is suppressed. As shown in FIG. 8, in the suction area, the contact position between the curved surface portion 16a of the vane tip and the inner peripheral edge 8a of the cam ring 8 greatly changes according to the pump rotation angle. When the local wear of the vane 16 is suppressed, the heat generated by this friction is suppressed. This makes it difficult for the oil film to break due to a decrease in the viscosity of the hydraulic oil interposed between the vane tip curved surface portion 16a and the inner peripheral edge 8a. Therefore, galling and image sticking due to contact between metals can be suppressed. As a result, the durability of the vane 16 and the cam ring 8 can be improved. Further, since it is not necessary to apply a coating (surface treatment) for preventing burn-in to the tip of the vane 16, a significant cost reduction can be realized.
In the cam ring 8, the first cam profile deviation Δr1 is smaller than the second cam profile deviation Δr2. In other words, even when the cam ring 8 is deformed by the pump internal pressure, the cam profile has a deviation region deviated radially outward from the perfect circular cam profile in the discharge region. Thus, even when the cam ring 8 is deformed by the internal pressure of the pump, the effect of suppressing galling and seizure of the vane 16 can be maintained.

  The bias region is biased outward in the radial direction with respect to the rotation axis O with respect to the perfect cam profile. Here, as a comparative example of the first embodiment, it is assumed that the cam profile is deviated radially inward from the perfect circular cam profile in the suction area. In this comparative example, as shown in FIG. 9, most of the suction area is in a compressed state, and the section in which the hydraulic oil can be sucked is short. Therefore, a problem such as cavitation may occur due to an insufficient suction amount. On the other hand, in the first embodiment, by displacing the cam profile radially outward from the perfect circular cam profile, hydraulic oil can be sucked over the entire suction area, and a sufficient suction amount is secured. Therefore, it is possible to suppress the occurrence of a problem such as cavitation. In the section between the end 21b of the second suction port 21 and the start 23a of the first discharge port 23 (so-called second confinement area), the rate of change of the radius of the cam profile is increased from a positive value in order to suppress abnormal noise. It is necessary to smoothly change to minus. For this reason, when the cam profile is deviated radially inward from the true circular cam profile as in the comparative example, the cam profile radius change rate must be sharply changed immediately before the second confining region. The cam profile becomes complicated. On the other hand, when the cam profile is deviated radially outward from the true circular cam profile as in the first embodiment, the suction area and the second confinement area can be smoothly connected, thereby suppressing complication of the cam profile. it can.

The bias region is provided over the entire suction region. As a result, a section in which the sliding range of the vane tip curved surface portion 16a changes (the circumferential direction range of the cam ring 8) can be sufficiently secured.
The cam profile of the cam ring 8 has an offset area even at the time of the minimum eccentricity. At the time of the minimum eccentricity, since the distance between the rotation axis O and the center P is minimum, the change in the cam profile is relatively small, and the sliding range of the curved surface portion 16a of the vane tip tends to be small. For example, at the time of relief when the relief valve 33 is opened, the pressing force of the vane tip curved surface portion 16a is strong and the amount of eccentricity of the cam ring 8 is small, so that the vane tip curved surface portion 16a is liable to seize and seize. Therefore, when the cam profile has an offset area at the time of the minimum eccentricity, the vane 16 can be prevented from galling and seizing at the time of the minimum eccentricity.
The vane 16 has an arc-shaped vane tip curved surface portion 16a at a radially inner tip, and an outer peripheral edge of the vane tip curved surface portion 16a is an inner peripheral edge 8a of the cam ring 8 in a range exceeding 40% in a suction region. Touch This allows the tip of the vane 16 to be used in a wide range, so that local friction can be effectively suppressed.
Assuming that the curvature radius of the vane tip curved surface portion 16a is rv and the thickness of the vane 16 is T, the vane 16 satisfies 2 × T ≦ rv. As shown in FIG. 10, even when only the cam profile of the cam ring 8 of the first embodiment is employed, the contact range of the vane 16 can be greatly expanded as compared with the conventional circular cam profile. Further, by setting the radius of curvature rv of the curved surface portion 16a of the vane tip to be at least twice the plate thickness T of the vane 16, the contact range of the vane 16 is further extended to twice or more, and the local wear of the vane 16 is further reduced. It can be suppressed effectively.

[Embodiment 2]
Since the basic configuration of the second embodiment is the same as that of the first embodiment, only the portions different from the first embodiment will be described.
FIG. 11 is a view showing the relationship between the rotation axis O of the drive shaft 6 and the center P of the inner peripheral edge 8a of the cam ring 8 in the variable displacement vane pump 1 according to the second embodiment.
The second embodiment differs from the first embodiment in that the center P of the cam profile of the cam ring 8 is offset toward the suction area. The cam ring 8 is provided in the pump element accommodating space 4a so as to be always biased toward the suction area with respect to the rotation axis O regardless of the operation and non-operation of the variable displacement vane pump 1 and the amount of eccentricity of the cam ring 8 with respect to the rotor 7. I have.
In the second embodiment, the cam ring 8 is offset to the suction area side, that is, the cam is raised, so that the cam profile radius change rate in the suction area can be further shifted to the plus side. In other words, the cam profile is deviated more radially outward than the perfect circular cam profile by raising the cam, so that the deviated area at the time of the minimum eccentricity and the deformation of the cam ring can be further expanded. As a result, seizure and seizure of the vane 16 at the time of minimum eccentricity and cam ring deformation can be suppressed.

[Other embodiments]
As described above, the embodiment for carrying out the present invention has been described. However, 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 a range not departing from the gist of the invention. Are also included in the present invention.
In the cam ring, the center of the outer peripheral surface may be deviated from the center of the inner peripheral surface.
The pressure plate and the adapter ring may be provided integrally with the front housing.
The suction port and the discharge port may be provided only on one of the pressure plate and the rear housing.
The vane tip curved surface portion only needs to be in contact with the inner peripheral edge of the cam ring within a range exceeding 40% of the length of the outer peripheral edge.

The technical ideas that can be grasped from the embodiment described above will be described below.
In one embodiment, the pump device is a pump housing, which has a pump element housing space, a suction passage, a discharge passage, a suction port, and a discharge port, and the suction passage is connected to the suction port. The discharge passage is connected to the discharge port, the pump housing, a drive shaft rotatably provided in the pump housing, a rotor provided in the drive shaft, having a plurality of slits, A plurality of vanes formed of a metal material and a cam ring, which are movably provided in each of the plurality of slits, are formed in an annular shape, and are provided in the pump element housing space; A plurality of pump chambers are formed together with the rotor and the plurality of vanes, and a first fluid pressure chamber and a second fluid pressure chamber are formed in the pump housing space. The port is open to a region of the plurality of pump chambers where the volume of the pump chamber increases with rotation of the drive shaft, and the discharge port is configured to rotate the drive shaft after the plurality of pump chambers. The first fluid pressure chamber is a space provided on the radial outside of the cam ring in the radial direction with respect to the rotation axis of the drive shaft. The volume is reduced as the amount of eccentricity between the rotation axis of the drive shaft and the center of the inner peripheral edge of the cam ring increases, and the second fluid pressure chamber relates to the rotation axis of the drive shaft. A space provided radially outside the cam ring in the radial direction, the space being provided in a portion where the volume increases as the amount of eccentricity between the rotation axis of the drive shaft and the center of the inner peripheral edge of the cam ring increases. The pump is movable in the pump element receiving space based on a pressure difference between the first fluid pressure chamber and the second fluid pressure chamber, and a line along an inner peripheral edge of the cam ring is defined as a cam profile, and the driving is performed. The range from the beginning to the end of the suction port in the circumferential direction with respect to the rotation axis of the shaft is defined as a suction area, and on a cross section perpendicular to the rotation axis of the drive shaft, is orthogonal to the rotation axis of the drive shaft, and An axis passing through a point bisecting a section between the end of the discharge port and the start of the suction port in the circumferential direction with respect to the rotation axis of the shaft is defined as a first axis, orthogonal to the first axis, and the cam An axis passing through a point bisecting a section between a pair of intersections where the profile and the first axis intersect is defined as a second axis, and an intersection of the first axis and the second axis is defined as a cam profile center point, Previous An axis passing through the center point of the cam profile and the end of the suction port is defined as a third axis, and a length between a point at which the third axis and the cam profile intersect and the center point of the cam profile is defined as a radius of a perfect circular cam profile. When the circular arc having the center of the cam profile as the center and having the radius of the circular cam profile is defined as a circular cam profile, the cam profile is, in the suction area, the drive shaft with respect to the circular cam profile. Said cam ring having a biased area biased outward or inward in a radial direction with respect to the axis of rotation of said cam ring.

  In a more preferred aspect, in the above aspect, the cam profile when the drive shaft is stopped and a discharge pressure is not acting on the discharge region is a cam profile in a first state, and the cam profile is defined as a cam profile in a first state from the cam profile center point. The distance to the cam profile in the first state is defined as the radius of the cam profile in the first state, and the cam profile when the discharge pressure is acting on the discharge area with the rotation of the drive shaft is the cam in the second state. The cam profile in the first state and the cam profile in the second state are defined as a profile, and a distance from the cam profile center point to the cam profile in the second state is defined as a cam profile radius in the second state. In the suction area, when compared at the same position in the circumferential direction with respect to the rotation axis of the drive shaft, The maximum value of the absolute value of the difference between the cam profile radius in the first state and the cam profile radius in the second state is defined as a first cam profile deviation amount, and the true circular cam profile and the cam profile in the first state are calculated. In the suction area, the maximum value of the absolute value of the difference between the true circular cam profile radius and the cam profile radius in the first state when compared at the same position in the circumferential direction with respect to the rotation axis of the drive shaft. When the second cam profile deviation is set, the cam ring has a shape such that the cam profile in the first state is such that the first cam profile deviation <the second cam profile deviation.

In another preferred aspect, in any one of the above aspects, the offset region is offset outwardly in a radial direction with respect to a rotation axis of the drive shaft with respect to the circular cam profile.
In still another preferred aspect, in any of the above aspects, the offset region is provided over the entire suction region.
In still another preferred embodiment, in any one of the above-described embodiments, the cam ring is configured such that when the amount of eccentricity between the rotation axis of the drive shaft and the center of the inner peripheral edge of the cam ring is minimum, the cam profile defines the bias region. Have.
In still another preferred aspect, in any of the above aspects, the vane has a vane tip curved surface portion provided at a radially inner tip with respect to a rotation axis of the drive shaft, and the vane tip curved surface portion is In a cross section perpendicular to the rotation axis of the drive shaft, the drive shaft has an arc shape convex toward the inside in the radial direction, and the vane has a length of an outer peripheral edge of the vane tip curved surface portion in the suction area. Of these, in the range exceeding 40%, it is in contact with the inner peripheral edge of the cam ring.

In still another preferred aspect, in any of the above aspects, the vane has a vane tip curved surface portion provided at a radially inner tip with respect to a rotation axis of the drive shaft, and the vane tip curved surface portion is In a section perpendicular to the rotation axis of the drive shaft, the drive shaft has an arc shape having a convex shape toward the inside in the radial direction and having a radius of curvature rv, and the vane in the circumferential direction with respect to the rotation axis of the drive shaft. When the thickness is T, the vane is
2 × T ≦ rv
Having a shape satisfying
In still another preferred aspect, in any one of the above aspects, the drive shaft is stopped, and the cam profile when the discharge pressure is not acting on the discharge area is set as a cam profile in a first state, When the cam profile when the discharge pressure is acting on the discharge area with the rotation of the cam ring is a cam profile in the second state, the cam ring is positioned at the center of the cam profile in the first state and the second state. Is provided in the pump element accommodating space such that the center of the cam profile in the state (1) is deviated toward the suction area side from the first axis.

1 Variable displacement vane pump (pump device)
4 Pump housing
4a Pump element accommodation space
5 Pump elements
6 Drive shaft
7 Rotor
7a slit
8 Cam ring
8a Inner circumference
14a 1st fluid pressure chamber
14b 2nd fluid pressure chamber
16 Vane
16a Curved surface of vane tip
17 Pump room
18 1st suction port
19a Suction passage
19b Discharge passage
21 Second suction port
21b termination
23 1st discharge port
23a beginning
25 2nd discharge port
O Rotation axis
P center

Claims (8)

In the pump device,
A pump housing having a pump element housing space, a suction passage, a discharge passage, a suction port, and a discharge port,
The suction passage is connected to the suction port,
The discharge passage is connected to the discharge port,
Said pump housing;
A drive shaft rotatably provided in the pump housing,
A rotor provided on the drive shaft and having a plurality of slits,
A plurality of vanes formed movably provided in each of the plurality of slits and formed of a metal material,
A cam ring, which is formed in an annular shape and is provided in the pump element accommodating space, forms a plurality of pump chambers together with the rotor and the plurality of vanes, and includes a first fluid pressure in the pump accommodating space. A chamber and a second fluid pressure chamber,
The suction port is open to a region where the volume of the pump chamber increases with rotation of the drive shaft, among the plurality of pump chambers,
The discharge port is, after a plurality of the pump chambers, open to a discharge area where the volume of the pump chamber decreases with the rotation of the drive shaft,
The first fluid pressure chamber is a space provided radially outside the cam ring in a radial direction with respect to a rotation axis of the drive shaft, and is a space between the rotation axis of the drive shaft and a center of an inner peripheral edge of the cam ring. It is provided in the part where the volume decreases as the amount of eccentricity increases,
The second fluid pressure chamber is a space provided radially outside the cam ring in a radial direction with respect to a rotation axis of the drive shaft, and is eccentric between a rotation axis of the drive shaft and a center of an inner peripheral edge of the cam ring. It is provided in the part where the volume increases as the amount increases,
Movable in the pump element housing space based on a pressure difference between the first fluid pressure chamber and the second fluid pressure chamber;
A line along the inner peripheral edge of the cam ring is defined as a cam profile,
The range from the start end to the end of the suction port in the circumferential direction with respect to the rotation axis of the drive shaft is a suction area,
On a cross section perpendicular to the axis of rotation of the drive shaft, between the end of the discharge port and the start of the suction port in a circumferential direction about the axis of rotation of the drive shaft, which is orthogonal to the axis of rotation of the drive shaft. An axis passing through a point bisecting the section is defined as a first axis,
An axis that is orthogonal to the first axis and that passes through a point bisecting a section between a pair of intersections where the cam profile and the first axis intersect is referred to as a second axis,
An intersection of the first axis and the second axis is defined as a cam profile center point,
An axis passing through the cam profile center point and the end of the suction port is defined as a third axis,
A length between a point where the third axis and the cam profile intersect and a center point of the cam profile is defined as a true circular cam profile radius,
When an arc having the radius of the perfect circular cam profile is defined as a perfect circular cam profile with the cam profile center point as a center,
The cam profile has, in the suction region, a bias region that is biased outward or inward in the radial direction with respect to the rotation axis of the drive shaft with respect to the true circular cam profile.
Said cam ring;
Pump device having The pump device according to claim 1,
The cam profile when the drive shaft is stopped and the discharge pressure is not acting on the discharge area is defined as a cam profile in a first state, and a distance from the center point of the cam profile to the cam profile in the first state. Is the cam profile radius in the first state,
The cam profile when the discharge pressure is acting on the discharge area with the rotation of the drive shaft is defined as a cam profile in a second state, and a distance from the center point of the cam profile to the cam profile in the second state. Is the cam profile radius in the second state,
The cam in the first state when the cam profile in the first state and the cam profile in the second state are compared at the same position in the suction area in the circumferential direction with respect to the rotation axis of the drive shaft. The maximum value of the absolute value of the difference between the profile radius and the cam profile radius in the second state is defined as a first cam profile deviation amount,
When comparing the true circular cam profile and the cam profile in the first state at the same position in the suction direction in the circumferential direction with respect to the rotation axis of the drive shaft, the true circular cam profile radius and the first cam profile radius are compared. When the maximum value of the absolute value of the difference between the cam profile radii in the state of
The cam ring has a cam profile in the first state,
A pump device having a shape such that the first cam profile deviation amount <the second cam profile deviation amount. The pump device according to claim 1,
The pump device, wherein the biasing region is biased outward with respect to the true cam profile in a radial direction with respect to a rotation axis of the drive shaft. The pump device according to claim 1,
The pump device, wherein the bias region is provided over the entire suction region. The pump device according to claim 1,
The pump device, wherein the cam profile has the bias region when the amount of eccentricity between the rotation axis of the drive shaft and the center of the inner peripheral edge of the cam ring is minimum. The pump device according to claim 1,
The vane has a vane tip curved surface portion provided at a tip inside in a radial direction with respect to a rotation axis of the drive shaft,
The vane tip curved surface portion has an arc shape that is convex toward the inside in the radial direction in a cross section perpendicular to the rotation axis of the drive shaft,
The pump device, wherein the vane is in contact with an inner peripheral edge of the cam ring in a range exceeding 40% of a length of an outer peripheral edge of the vane tip curved surface portion in the suction area. The pump device according to claim 1,
The vane has a vane tip curved surface portion provided at a tip inside in a radial direction with respect to a rotation axis of the drive shaft,
The vane tip curved surface portion, in a cross section perpendicular to the rotation axis of the drive shaft, is convex toward the inside in the radial direction and has an arc shape having a curvature radius rv,
When the thickness of the vane in the circumferential direction with respect to the rotation axis of the drive shaft is T, the vane is:
2 × T ≦ rv
Pump device having a shape that satisfies the following. The pump device according to claim 1,
The cam profile when the drive shaft is stopped and no discharge pressure is applied to the discharge region is defined as a cam profile in a first state,
When the cam profile when the discharge pressure is acting on the discharge region with the rotation of the drive shaft is a cam profile in a second state,
The cam ring is provided in the pump element housing space such that a center of the cam profile in the first state and a center of the cam profile in the second state are deviated toward the suction area with respect to the first axis. Pumping equipment.

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