JP2823306B2 - Variable displacement vane pump - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement vane pump used as an oil supply pump for an automatic transmission of an automobile, for example.

[Conventional technology]

Conventionally, as this kind of variable displacement vane pump,
For example, one disclosed in JP-A-55-17696 is known.

The conventional pump includes a pump housing having a fluid suction passage and an outflow / discharge passage, a cam ring (ring member) provided in the pump housing, and a rotor (rotor) provided in the cam ring and driven to rotate. When,
A plurality of vanes (blades) are provided on the outer periphery of the rotor so as to be able to advance and retreat in the radial direction, and the outer ends in the radial direction are in sliding contact with the inner peripheral surface of the cam ring. The cam ring is swingably supported on the pump housing via a pivot pin so that the center thereof can be eccentric with respect to the rotation axis of the rotor, and the amount of eccentricity is increased by the spring force of the cam spring. Biased in the direction. A seal member is interposed between the outer peripheral surface of the cam ring and the inner peripheral surface of the pump housing at a position substantially opposite to the pivot pin, and the seal member and the pivot pin allow the outer peripheral surface of the cam ring and the inner peripheral surface of the pump housing to intersect. The space member therebetween is partitioned, and a control pressure chamber is formed in the partitioned space portion.
The control pressure chamber is configured such that a control pressure according to the flow rate (discharge amount) of the fluid in the fluid discharge path is introduced from the fluid discharge path via a control valve, and the eccentric amount is controlled by the control pressure. Is configured to be biased in the decreasing direction.

In this conventional pump, by rotating the rotor with the above-described configuration, the fluid is sucked into a pump chamber formed between the inner peripheral surface of the cam ring and the outer peripheral surface of the rotor through the fluid suction passage, and the pump is driven. The liquid can be discharged from the chamber through the fluid discharge path. Further, in this conventional pump, the eccentric amount of the cam ring can be changed according to the control pressure introduced into the control pressure chamber, and the discharge amount can be changed according to the eccentric amount of the cam ring. ing.

By the way, conventionally, as described in the same gazette, a seal member used for a pump having the above-described configuration is formed in a plate shape (quadratic prism shape), and is held in a state in which a tip end protrudes from an outer peripheral portion of a cam ring. The tip is pressed against the inner peripheral surface of the pump housing, or is formed in a pin shape (cylindrical shape), fitted and held on the outer peripheral portion of the cam ring, and a part of the peripheral edge is pressed against the inner peripheral surface of the pump housing. (See Japanese Utility Model Publication No. 63-19597).

[Problems to be solved by the invention]

As described above, in the conventional pump, since the seal member has a plate shape or a pin shape, the contact state between the seal member and the outer peripheral surface of the cam ring and the contact state between the seal member and the inner peripheral surface of the pump housing are substantially linear contact. In a close state,
There is a problem that the sealing length is short and the sealing property of the sealing member is not good.

Moreover, since the contact portion of the seal member with the outer peripheral surface of the cam ring and the inner peripheral surface of the pump housing was small,
There is a problem that the durability of the seal member is low, such as the sliding resistance when the cam ring swings on the small contact portion and the contact portion wears quickly.

In view of the above circumstances, an object of the present invention is to provide a variable displacement vane pump having high sealing performance and high durability of a sealing member.

[Means for solving the problem]

A variable displacement vane pump according to the present invention includes a pump housing having a fluid suction passage and a fluid discharge passage, a cam ring provided in a substantially cylindrical bore of the pump housing, and a rotary drive provided in the cam ring. And a plurality of vanes provided on the outer peripheral portion of the rotor so as to be able to advance and retreat in the radial direction, and having a radially outer end slidably in contact with an inner peripheral surface of the cam ring.
The center is swingably supported by the pump housing so that the center can be eccentric with respect to the rotation axis of the rotor,
A seal member that partitions a space between the outer peripheral surface of the cam ring and the inner peripheral surface of the pump housing is provided at a position apart from the center of oscillation of the cam ring between the outer peripheral surface of the cam ring and the inner peripheral surface of the pump housing. Is provided,
By rotating the rotor, fluid is drawn through the fluid suction passage into a pump chamber formed between the inner peripheral surface of the cam ring and the outer peripheral surface of the rotor, and flows from the pump chamber through the fluid discharge passage. And the discharge amount of the fluid from the fluid discharge path is changed in accordance with the eccentric amount of the cam ring. An opposite portion is formed in an arc surface centered on the cam ring swing center, and the seal member is interposed between this surface and the inner peripheral surface of the pump housing. The seal member has a substantially crescent shape as a whole. And a surface on the cam ring outer peripheral surface side and a surface on the pump housing inner peripheral surface side are formed in arc surfaces along respective corresponding surfaces. That.

In particular, in the above pump, it is preferable to provide a lubrication groove on a surface of the seal member on the outer peripheral surface side of the cam ring.

[Action]

According to the above configuration, the seal member comes into contact with the outer peripheral surface of the cam ring, the inner peripheral surface of the pump housing, and the inner surface of the pump housing for a long distance, and the two space portions separated by the seal member are separated by the seal member. The sealing is ensured.

In particular, if a groove for lubrication is provided on the surface of the seal member on the outer peripheral surface side of the cam ring, the fluid accumulated in the groove lubricates between the seal member and the outer peripheral surface of the cam ring, and the movement of the cam ring becomes smooth. .

〔Example〕

1 and 2 show one embodiment of a variable displacement vane pump according to the present invention.

This variable displacement vane pump has a pump housing 1
And an annular cam ring 2 and a rotor 3.

The pump housing 1 is composed of a passage-side housing 1a and a cover-side housing 1b. A column-shaped recess having one end opened at the center of the passage-side housing 1a is formed. It is closed by 1b to form a housing bore 1c. A fluid suction passage 11 and a fluid discharge passage 12 are formed through the passage-side housing 1a, and the fluid suction passage 11 and the fluid discharge passage 12 are formed.
Are open at the outer peripheral flange portion of the passage-side housing 1a to form a suction port 11a and a discharge port 12a. On the other hand, the other ends of the fluid suction passage 11 and the fluid discharge passage 12 open to the pump chamber 6 and the second control pressure chamber 92, respectively, in the process of increasing the volume, which will be described later.

The cam ring 2 has a circular inner peripheral surface 21 and is provided in the housing bore 1c. Each side surface of the cam ring 2 is in close contact with each side surface (inside surface of the pump housing) 13, 14 of the housing bore 1c.

The rotor 3 is formed with a smaller diameter than the circular inner peripheral surface 21 of the cam ring 2, and is provided in the circular inner peripheral surface 21 of the cam ring 2 with both side surfaces being in close contact with the pump housing inner side surfaces 13 and 14, respectively. . Further, the rotor 3, the rotor drive shaft 3a inserted through the cover-side housing 1b and is connected, the rotor drive shaft 3a passing through the center O ₁ of the peripheral surface (inner peripheral surface pump housing) 15 of the housing bore 1c It rotates in the direction of arrow C in FIG. 1 around the axis α.

A plurality of vane grooves 31 are radially formed on the outer periphery of the rotor 3. Each vane groove 31 is open to the rotor outer peripheral surface 32, and the vane 4 is fitted in each vane groove 31 so as to be able to advance and retreat in the rotor radial direction.

Annular grooves 33 and 34 are formed on both side surfaces of the rotor 3, respectively, and a guide ring 35 is provided in the groove 33 formed on the inner peripheral surface 14 side of the pump housing.

The vane 4 is urged outward in the rotor radial direction by the guide ring 35 and centrifugal force caused by the rotation of the rotor 3,
The outer end in the radial direction is constantly pressed against the circular inner peripheral surface 21 of the cam ring 2 so as to slide on the circular inner peripheral surface 21.

Outer peripheral surface 22 of cam ring 2 and inner peripheral surface 15 of pump housing
Are formed with semicircular concave portions 23a and 18 facing each other. A cylindrical pivot roller 23 is provided between these recesses 23a, 18 with its outer peripheral surface in contact with the inner peripheral surface of each of the recesses 23a, 18, and the cam ring 2 is pivoted by the pump housing 1. arrow a in Figure 1 the center O ₂ of the roller 23 as a swing center and are swingably supported in the B direction. Thereby, the center O ₃ of the cam ring 2 (the center of the circular inner peripheral surface 21) can be eccentric with respect to the rotation axis α of the rotor 3. The swing center of the cam ring 2
The distance from O ₂ to the rotation axis α of the rotor 3 is set to be equal to the distance from the swing center O ₂ to the center O _{3 of the} cam ring 2.

A spring seat 24 is formed on one side of the cam ring 2 on the one side of the center line β passing through the center O ₃ and the swing center O ₂ . This spring seat 24 has a cam ring 2
Is applied in the direction of increasing the amount of eccentricity (the direction of arrow B in FIG. 1), whereby the cam ring 23 is pressed to the maximum eccentric position. The spring force of the cam spring 25 can be adjusted by adjusting screws (not shown).

On the other side of the outer peripheral surface 22 of the cam ring 2 that is separated from the center line β, a stopper surface 26 is formed which abuts a part of the inner peripheral surface 15 of the pump housing at the maximum eccentric position of the cam ring 2.

Swing center O ₂ and the substantially opposite side of the portion (surface) 22 of the cam ring outer peripheral surface 22 is formed in an arcuate surface around the swing center O _2. The seal member 5 is interposed between the surface 22a and the inner peripheral surface 15 of the pump housing, and the space between the outer peripheral surface 22 of the cam ring and the inner peripheral surface 15 of the pump housing is formed by the seal member 5 and the pivot roller 23. It is divided into two parts. A first control pressure chamber 91 is provided on one side (an eccentric side of the cam ring) of the two divided space portions, and a second control pressure chamber 92 is provided on the other side.

Fluid pressure is introduced into the first and second control pressure chambers 91 and 92, respectively, as described later. The first control pressure chamber 91 urges the cam ring 2 in the direction of decreasing the amount of eccentricity by the introduced fluid pressure. , Second control pressure chamber 92
Is adapted to urge the cam ring 2 in the direction of increasing the amount of eccentricity by the introduced fluid pressure.

As shown in FIG. 4, the sealing member 5 is formed in a substantially crescent shape as a whole. The seal member 5 has an inner peripheral surface (a surface on the cam ring outer peripheral surface 22 side) 51 formed in an arc surface along the arc-shaped portion 22a of the cam ring outer peripheral surface 22 and an outer peripheral surface (pump housing inner peripheral surface 15). Side surface) 52
Are formed on an arc surface along the circular inner peripheral surface 15 of the pump housing 1. Further, both sides of the seal member 5 are in close contact with the inner surfaces 13, 14 of the pump housing, respectively.

The pivot roller 23 is provided in a state where both side surfaces are in close contact with the pump housing inner side surfaces 13 and 14, respectively. For this reason, a sealing action is given to the pivot roller 23, and the space between the first control pressure chamber 91 and the second control pressure chamber 92 is reliably sealed by the pivot roller 23 and the seal member 5.

The space surrounded by the inner peripheral surface 21 of the cam ring 2, the outer peripheral surface 32 of the rotor 3, and the inner surfaces 3 and 14 of the pump housing is divided into a plurality of parts by the vane 4. A chamber 6 is formed. Each pump room 6
Since the center O ₃ of the cam ring 2 is eccentric with respect to the rotation axis α of the rotor 3, the volume increases and decreases with the rotation of the rotor 3.

A discharge groove 95 is formed on the inner surface 13 of the pump housing at the position of the pump chamber 6 in the latter half of the volume reduction process. As shown in FIG. 3, the pump chamber 6 and the second control pressure chamber 92 where the intermediate portion of the discharge groove 95 faces the portion of the cam ring 2 closer to the second control pressure chamber 92 than the pivot roller 23. And a communication passage 7 that communicates with.
A throttle (orifice) 73 is provided at an opening of the communication passage 7 on the pump chamber 6 side. Also, for the cam ring 2,
The pump chamber 6 in which the front end of the discharge groove 95 faces the first control pressure chamber 91 side of the pivot roller 23.
Fluid pressure introduction part which communicates with the first control pressure chamber 91
95b is formed.

Pump chamber 6 in the first half of the volume reduction process of cam ring inner peripheral surface 21
At the position, a side groove 21c is formed, and the side groove 21c prevents a sudden pressure fluctuation due to a decrease in the volume of the pump chamber 6.

In the above configuration, when the rotor 3 is rotated in the direction of arrow C from the state of FIG. 1 (the state in which the cam ring 2 is maximally eccentric), each pump chamber 6 also rotates and moves in the direction of arrow C while repeatedly increasing and decreasing the volume. . And each pump room mark 6
Communicates with the fluid suction passage 11 in the volume increasing step, sucks a fluid such as oil from the suction port 11a through the fluid suction path 11, and communicates with the fluid pressure introduction path 95b and the communication path 7 in the volume decreasing step. Fluid suction passage 95b
And discharge toward the communication path 7. The fluid discharged toward the fluid pressure introduction path 95b is introduced into the first control pressure chamber 91 through the fluid pressure introduction path 95b, and the fluid discharged toward the communication path 7 passes through the communication path 7. After being guided to the second control pressure chamber 92, it is guided to the fluid discharge path 12 and discharged from the discharge port 12a.

Since the communication passage 7 is provided with the throttle portion 73,
Differential pressure before and after the throttle section 73 is generated, the aperture section 73 downstream second control pressure chamber 92, the fluid pressure P ₂ of reduced relative to the fluid pressure P ₁ of the aperture section 73 upstream is introduced. On the other hand, the throttle unit 73
AC body pressure P ₁ on the upstream side of, since the upstream portion of the upstream portion of the throttle portion 73 and the fluid pressure introducing passage 95b is communicated via the discharge groove 95, the through flow breakdown voltage introduction path 95b It is introduced into one control pressure chamber 91. Thereby, the cam ring 2
The, in addition to the spring force F of the cam spring 25 which acts in the increasing direction of the eccentricity, the high fluid pressure P ₁ is applied in the decreasing direction of the eccentricity, the low fluid pressure P ₂ is applied to the direction of increasing eccentricity I will be. That is, the cam ring 2, the high fluid pressure P ₁ low fluid pressure
The pressure difference ΔP from P ₂ (= P ₁ −P ₂ ) acts against the spring force F of the cam spring 25.

When the rotation speed N of the rotor 3 is low, the discharge amount Q is small, and the differential pressure ΔP is also small. Therefore, in this case, the spring force F of the cam spring 25 exceeds the force acting on the cam ring 2 due to the differential pressure ΔP, and the cam ring 2 is held at the maximum eccentric position. As a result, when the rotation speed N of the rotor 3 is low, the discharge amount Q increases in proportion to the rotation speed N.

On the other hand, when the rotation speed N of the rotor 3 increases, the discharge amount Q increases, and the differential pressure ΔP also increases. Here, for example, if the spring force F of the cam spring 25 is set so as to balance the force due to the differential pressure ΔP when the discharge amount Q reaches the predetermined amount Q ₀ , the rotational speed N of the rotor 3 increases. Te, the discharge amount Q reaches a predetermined amount Q _0, the force due to the differential pressure ΔP cam spring
By overcoming the spring force F of 25, the cam ring 2 swings in the direction of decreasing the amount of eccentricity. As a result, the amount of eccentricity of the cam ring 2 decreases, the displacement decreases, and the discharge amount Q
Is maintained so as not to exceed a predetermined amount Q ₀ . That is, according to the configuration of the pump, the characteristic of the rotor rotation speed N-discharge amount Q as shown in FIG. 5 can be obtained.

Moreover, in this pump, and an arcuate surface around the cam ring swing center O ₂ of the cam ring swing center O ₂ and the substantially opposite side portions 22a of the cam ring outer peripheral surface 22, the surface 22a
A seal member 5 is provided between the seal member 5 and the inner peripheral surface 15 of the pump housing, and the seal member 5 is formed in a substantially crescent shape as a whole. The inner peripheral surface 51 of the seal member 5 is formed into an arc surface along the arc-shaped portion 22a of the outer peripheral surface 22 of the cam ring, and the outer peripheral surface 52 of the seal member 5 extends along the circular inner peripheral surface 15 of the pump housing 1. It is formed on an arc surface. For this reason,
In addition to the seal member 5 and the outer peripheral surface 22 of the cam ring, the seal member 5 and the inner peripheral surface 15 of the pump housing, the seal member 5 and the inner surfaces 13 and 14 of the pump housing come into contact with each other over a long distance. The seal between the pressure chamber 91 and the second control pressure chamber 92 can be reliably sealed by the seal member 5.

 FIG. 6 shows another example of the seal member 5a.

The seal member 5a has a plurality of lubrication grooves 5 on the inner peripheral surface 51a.
3a are recessed at equal intervals in the circumferential direction. In this way, the fluid introduced into the pump housing 1 accumulates in the lubrication groove 53a, and the accumulated fluid lubricates between the seal member 5a and the cam ring outer peripheral surface 22. The crab can be swung. Since a part of the side surface of the seal member 5a faces the fluid suction passage 11 in the lubrication groove 53a, the fluid is guided from the fluid suction passage 11 (see FIG. 2).

In the above embodiment, a pivot portion corresponding to the pivot roller 23 may be formed so as to be integrally protruded from a part of the cam ring outer peripheral surface 22, or both ends of the pivot roller 23 may be respectively formed on the pump housing inner surface 13, It may be embedded in 14. Further, the seal member 5 may be securely fixed by a pin or the like.

〔The invention's effect〕

In the variable displacement vane pump according to the present invention, a portion of the outer peripheral surface of the cam ring substantially opposite to the center of swing of the cam ring is formed in an arcuate surface centered on the center of swing of the cam ring, and between this surface and the inner circumferential surface of the pump housing. The seal member is formed in a substantially crescent shape as a whole, and the surface on the outer peripheral surface side of the cam ring and the inner peripheral surface side of the pump housing are formed as arc surfaces along the respective corresponding surfaces. ing. For this reason, the seal member comes into contact with the outer peripheral surface of the cam ring, the inner peripheral surface of the pump housing, and the inner surface of the pump housing over a long distance, and the sealing property of the seal member is improved.

In addition, since the contact portion of the seal member with the outer peripheral surface of the cam ring, the inner peripheral surface of the pump housing, and the inner surface of the pump housing becomes longer, even if the dimensional tolerances of the respective contact surfaces of the seal member, the cam ring and the pump housing are loosened, sufficient sealing is achieved. The effect can be obtained. For this reason, processing of a seal member, a cam ring, and a pump housing becomes easy. Moreover, since the seal member is formed in a substantially crescent shape as a whole, the inner and outer peripheral surfaces of the seal member can be easily processed by a lathe or the like, and the manufacture of the seal member becomes easy. Therefore, the entire pump can be configured at low cost.

Furthermore, since the contact portion of the seal member with respect to the outer peripheral surface of the cam ring, the inner peripheral surface of the pump housing, and the inner surface of the pump housing becomes large, sliding resistance and the like when the cam ring swings on the large contact portion are dispersed. The durability of the sealing member is improved.

In addition, since the entire seal member is formed in a substantially crescent shape and inserted into the space between the outer peripheral surface of the cam ring and the inner peripheral surface of the pump housing, the sealing performance of the seal member is improved without increasing the size of the entire pump. be able to.

In particular, if a groove for lubrication is provided on the surface of the seal member on the outer peripheral surface side of the cam ring, the fluid accumulated in the groove lubricates the gap between the seal member and the outer peripheral surface of the cam ring, so that the cam ring smoothly swings. Will be able to do it.

[Brief description of the drawings]

FIG. 1 is a front view showing one embodiment of a variable displacement vane pump according to the present invention except for a cover side housing, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. III-III
FIG. 4 is a perspective view showing the seal member, FIG.
FIG. 6 is a graph showing the relationship between the number of rotations of the rotor and the discharge amount, and FIG. 6 is a perspective view showing another example of the seal member. 1 ... pump housing, 1c ... bore of pump housing, 2 ... cam ring, 3 ... rotor, 4 ... vane,
5,5a seal member 6, pump chamber 11, fluid suction passage 12, fluid discharge passage 15, inner peripheral surface of pump housing 21, inner peripheral surface of cam ring 22, cam ring Outer peripheral surface, 22a: A portion of the outer peripheral surface of the cam ring substantially opposite to the center of swing of the cam ring, 32: Outer peripheral surface of the rotor, 51, 51a: A surface on the outer peripheral surface of the cam ring of the seal member, 52, 52a: Seal member plane in the pump housing circumferential surface, 53a ...... lubrication grooves, O ₂ ...... swinging center of the cam ring, O ₃ center ...... cam ring, the axis of rotation of the alpha ...... rotor.

Claims (2)

(57) [Claims] A pump housing having a liquid suction passage and a fluid discharge passage; a cam ring provided in a substantially cylindrical bore of the pump housing; a rotor provided in the cam ring and driven to rotate; A plurality of vanes are provided on the outer peripheral portion of the rotor so as to be able to advance and retreat in the radial direction, and the outer end in the radial direction is in sliding contact with the inner peripheral surface of the cam ring, and the center of the cam ring is on the rotation axis of the rotor. The cam ring is swingably supported by the pump housing so as to be eccentric with respect to the cam ring, and the cam ring is located between the outer peripheral surface of the cam ring and the inner peripheral surface of the pump housing and away from the center of swing of the cam ring. A seal member is provided for partitioning a space between the outer peripheral surface and the inner peripheral surface of the pump housing. It is sucked into a pump chamber formed between the inner peripheral surface of the cam ring and the outer peripheral surface of the rotor through the inlet path, discharged from the pump chamber through the fluid discharge path, and the eccentric amount of the cam ring. In the variable displacement vane pump configured to change the discharge amount of the fluid from the fluid discharge path in accordance with the above, a portion of the outer peripheral surface of the cam ring substantially opposite to the center of the cam ring swing is the center of the cam ring swing. It is formed on an arc surface that is the center,
The seal member is interposed between the surface and the inner peripheral surface of the pump housing. The seal member is formed in a substantially crescent shape as a whole, and has a cam ring outer peripheral surface side and a pump housing inner peripheral surface side. A variable displacement vane pump, wherein the surfaces are formed in arcuate surfaces along respective corresponding surfaces. 2. The variable displacement vane pump according to claim 1, wherein a lubrication groove is provided on a surface of the seal member on the outer peripheral surface side of the cam ring.