JP2863590B2 - 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.

[Prior art] Conventionally, as this kind of variable displacement vane pump,
For example, one disclosed in Japanese Utility Model Publication No. 63-19597 is known.

This conventional pump includes a pump housing having a fluid suction passage and a fluid discharge passage, a cam ring (oscillating ring) provided in the pump housing, a rotor provided in the cam ring and driven to rotate, A plurality of vanes 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. Opposite semicircular concave portions are formed on the inner peripheral surface of the pump housing and the outer peripheral surface of the cam ring, respectively, and these concave portions are fitted to support pins having a circular cross section provided between the concave portions. The cam ring is swingably supported by the pump housing so that the center thereof can be eccentric with respect to the rotation axis of the rotor.

With this configuration, the conventional pump sucks fluid into the space between the inner peripheral surface of the cam ring and the outer peripheral surface of the rotor through the fluid suction passage by rotating the rotor. And the amount of fluid discharged from the fluid discharge path can be changed according to the amount of eccentricity of the cam ring.

[Problems to be solved by the invention]

As described above, in the configuration of the conventional pump, a support pin is separately provided to support the cam ring in a swingable manner. For this reason, the number of parts has been increased.

Moreover, in the conventional pump described above, since the discharge port opened in the space between the inner peripheral surface of the cam ring and the outer peripheral surface of the rotor communicates with the fluid discharge passage of the pump housing, the fluid discharge passage communicates with the discharge port. A high-pressure chamber having an open end is provided in a space between the inner peripheral surface of the pump housing and the outer peripheral surface of the cam ring, and the fluid flows from the discharge port to the fluid discharge path via the high-pressure chamber.

For this reason, a sealing member for maintaining the high-pressure chamber in a water-tight state is required, resulting in a further increase in the number of parts.

As a method of connecting the discharge port and the fluid discharge path without providing a high-pressure chamber, the discharge port is formed so as to bypass the space between the inner peripheral surface of the pump housing and the outer peripheral surface of the cam ring. However, there is a problem in that it is difficult to form a fluid discharge path and the cost increases.

In view of the above circumstances, an object of the present invention is to provide a variable displacement vane pump that can be configured at a low cost with a small number of components.

[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 the pump housing; a rotor provided in the cam ring and driven to rotate; A plurality of vanes that are provided on the outer peripheral portion of the cam ring so as to be able to advance and retreat in the radial direction, and whose radially outer ends are in sliding contact with the inner peripheral surface of the cam ring. The pump housing is swingably supported by the pump housing so as to be eccentric, and by rotating the rotor, fluid passes through the fluid suction passage between the inner peripheral surface of the cam ring and the outer peripheral surface of the rotor. The amount of fluid discharged from the fluid discharge path according to the amount of eccentricity of the cam ring while being sucked into the space and discharged from the fluid discharge path In the variable displacement vane pump configured to change, a pivot portion is integrally formed on a part of an outer peripheral surface of the cam ring, and a pivot recess is formed on a part of an inner peripheral surface of the pump housing, When the pivot portion is rotatably fitted in the pivot recess, the cam ring is swingably supported, and a fluid discharge passage is opened in the pivot recess, and the cam ring inner periphery is formed in the pivot portion. A communication path is provided for communicating a space portion between the surface and the outer peripheral surface of the rotor with the fluid discharge path.

[Action]

According to the above configuration, the cam ring can be swingably supported by the pivot portion formed integrally with the cam ring and the pivot recess provided in the pump housing, and the support pin is not required.

In addition, since the fluid discharge path is opened in the pivot concave portion, and the pivot portion is provided with a communication path communicating the space between the inner peripheral surface of the cam ring and the outer peripheral surface of the rotor and the fluid discharge path, high pressure is provided. A chamber is not required, and as a result, a seal member for partitioning the high-pressure chamber is not required.

〔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 includes a housing main body 1a and a cover-side housing 1b. A cylindrical concave portion having one end opened at the center of the housing main body 1a is formed. It is closed to form the housing lumen 1c. A fluid suction passage 11 and a fluid discharge passage 12 are formed through the housing body 1a. One end of each of the fluid suction passage 11 and the fluid discharge passage 12 is opened to an outer peripheral flange portion of the housing body 1a, and a suction port 11a is formed. And a discharge port 12a. In addition,
Part of the fluid suction passage 11 is also formed in the cover-side housing 1b. A pivot concave portion 18 is formed in a part of the peripheral surface (inner peripheral surface of the pump housing) 15 of the housing cavity 1c, and the other end of the fluid discharge passage 12 is opened in the pivot concave portion 18. doing.

The cam ring 2 has a circular inner peripheral surface 21 and is provided in the housing cavity 1c in such a manner that both side surfaces thereof are in close contact with the pump housing inner surfaces 13, 14 facing the housing cavity 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 cover side housing 1b in inserted through a rotor drive shaft (not shown) is connected via a drive flange 3a, the axis of the rotor drive shaft passing through the center O ₁ of the pump housing peripheral surface 15 It rotates in the direction of arrow C in FIG. 1 around 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, 34 are formed on both side surfaces of the rotor 3, respectively, and a guide ring 35 is provided in the groove 34 formed on the inner 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.

A pivot portion 23 is integrally formed on a part of the outer peripheral surface 22 of the cam ring 2 so as to protrude therefrom. The pivot portion 23 includes a cylindrical head 23a and a neck 23b connecting the head 23a and the outer peripheral surface 22. The head portion 23a of the pivot portion 23 is rotatably fitted to the pivot concave portion 18, and the cam ring 2 is fitted to the pump housing 1 in the arc-shaped inner peripheral surface of the pivot concave portion 18 (of the pivot portion 23). Head 23
arrow A in Figure 1 the center O ₂ as the center (pivot point) of a arc-shaped outer peripheral surface of) is pivotably 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. Incidentally, it is set to be equal to the distance from the distance and the pivot point O ₂ from pivot point O ₂ to the rotation axis α of the rotor 3 to the center O ₃ of the cam ring 2.

In the outer peripheral surface 22 of the cam ring 2, pivot point O ₂ and the cam ring 2
On one side of the center line β passing through the center O _{3 of}
A spring seat 24 is formed to protrude. The spring seat 24 receives the spring force of the cam ring 25 that urges the cam ring 2 in the direction in which the amount of eccentricity increases (the direction of arrow B in FIG. 1), whereby the cam ring 2 is pressed to the maximum eccentric position. ing.

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

A cylindrical seal pin 5 is interposed between the inner peripheral surface 15 of the pump housing and the outer peripheral surface 22 of the cam ring at a position substantially opposite to the pivot portion 23, and the seal pin 5 and the pivot portion 23 define the inner periphery of the pump housing. The space between the surface 15 and the outer peripheral surface 22 of the cam ring is divided into two parts, a drain chamber 91 is provided on one side and the other end of the fluid suction passage 11 is open, and a control pressure chamber 92 is provided on the other side (cam ring eccentric side). Is provided. The pivot portion 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, the pivot portion 23 is provided with a sealing function, and the space between the drain chamber 91 and the control pressure chamber 92 is reliably sealed by the pivot portion 23 and the seal pin 5. In addition, since the pivot portion 23 has a sealing function, the fluid discharge passage opening to the pivot concave portion 18 is formed.
The space between the drain 12 and the drain chamber 91 and the control pressure chamber 92 is also sealed by the pivot part 23. Sliding contact portion 22a to the seal pin 5 at the outer peripheral surface 22 of the cam ring 2 is formed in a circular arc surface centered on the pivot point O _2.

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 13 and 14 of the pump housing is divided into a plurality of parts by the vane 4. A chamber 6 is formed. 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 of each pump chamber 6 increases and decreases with the rotation of the rotor 3.

A suction groove 94 and a discharge groove 95 are formed on the inner surface 13 of the pump housing 1. The suction groove 94 is provided in the fluid suction passage 11.
To the pump chamber 6a in the process of increasing the volume, and the opening constitutes a suction port 94a. On the other hand, the discharge groove 9
5 extends from the center position of the head of the pivot portion 23 to the pump chamber 6b in the process of reducing the volume, opens to the pump chamber 6b, and constitutes a discharge port 95a at the opening. The discharge groove 9
5 means that even when the cam ring 2 swings, the discharge groove 95
A close contact portion between the side of the pivot portion 23 and the pump housing side 13 having a width enough to sufficiently seal the space between the pump housing side and the drain chamber 91 and between the discharge groove 95 and the control pressure chamber 92 is secured. It is formed to be.

As shown in FIG. 3, the head 23a of the pivot part 23 has
A communication passage 7 is formed by a cylindrical recess 71 opening toward the discharge groove 95 and a through hole 72 opening toward the other end of the recess 71 and the other end of the fluid discharge passage 12, respectively. Discharge groove 95 (discharge port 95a) and fluid discharge path 1
And 2 are in communication.

A flow control valve 8 including a spool 81 and a spool spring 82 is provided in the fluid discharge passage 12, and a feedback passage 83 is formed in the housing body 1a to communicate the middle of the fluid discharge passage 12 and the control pressure chamber 92. Have been. Then, a control pressure corresponding to the flow rate (discharge amount) passing through the fluid discharge passage 12 is generated by the flow control valve 8, and the control pressure passes through the feedback passage 83 and is controlled by the control pressure chamber.
The control pressure is applied to the cam ring 2 so as to urge the cam ring 2 in a direction to reduce the amount of eccentricity.

Note that the seal pin 5 is fitted and held in a semicircular recess formed in the housing body 1a. Also,
As shown in FIG. 4, the seal pin 5 has a back pressure chamber 52 formed at the rear thereof to receive the control pressure of the control pressure chamber 92, and the cam ring 2 is controlled by the control pressure introduced into the back pressure chamber 52.
Is pressed against the outer peripheral surface 22a.

In the configuration of the pump described above, 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), the pump chambers 6 also repeatedly increase and decrease the volume. It rotates and moves in the C direction. Each pump chamber 6 has a suction port in the process of increasing the volume.
A fluid such as oil guided to the suction port 94a through the fluid suction passage 11 from the suction port 11a is communicated with the suction port 11a, and communicates with the discharge port 95a in a volume reduction process to discharge the sucked fluid into the discharge port 95a. Discharge toward 95a. Discharge port 9
The fluid discharged to 5a is discharged from the discharge port 12a through the communication path 7 and the fluid discharge path 12.

When the rotation speed of the rotor 3 is increased, the discharge amount discharged from the discharge port 12a increases in proportion to the rotation speed. Further, as the discharge amount increases, the control pressure introduced into the control pressure chamber 92 also increases. When the discharge amount Q rotational speed is increased in the rotor 3 reaches a predetermined flow rate Q _0, the control pressure in the control pressure chamber 92 overcomes the spring force of the cam spring 25, the cam ring 2 decreases the eccentricity Rocks in the direction. Thus, the eccentric amount decreases the cam ring 2, displacement is reduced, the discharge amount Q is maintained so as not to exceed a predetermined flow rate Q _0. As a result, as shown in FIG. 5, the rotation speed is increased discharge amount Q is controlled so as not to exceed the predetermined flow rate Q _0.

The method of changing the amount of eccentricity of the cam ring 2 is not limited to the above embodiment. For example, a wire or the like is connected to the cam ring 2 so that the cam ring 2 can be operated from the outside via the wire or the like. Alternatively, the amount of eccentricity of the cam ring 2 may be changed by an external control means.

〔The invention's effect〕

In the variable displacement vane pump according to the present invention, a pivot portion is integrally formed on a part of an outer peripheral surface of a cam ring, and a pivot recess is formed on a part of an inner peripheral surface of a pump housing. The cam ring is swingably supported by the pump housing by rotatably fitting the portions. For this reason, the cam ring can be swingably supported without separately providing a support pin, and the support pin is not required, so that the configuration can be made inexpensively.

In addition, since the fluid discharge passage is opened in the pivot concave portion and the pivot portion is provided with a communication passage communicating the space between the inner peripheral surface of the pump housing and the outer peripheral surface of the cam ring and the fluid discharge passage, the high pressure is provided. There is no need to provide a chamber in the space, and as a result, a seal member for maintaining the high-pressure chamber in a watertight state is not required, and the number of seal members can be reduced. In addition, when the communication path is formed in the pivot portion, the thickness of the pump housing does not increase, and the mold of the pump housing does not become complicated. For this reason, it can be constructed more inexpensively.

[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 sectional view taken along the line IV-IV of FIG. 1, and FIG. 5 is a graph showing the relationship between the number of rotations of the rotor and the discharge amount. DESCRIPTION OF SYMBOLS 1 ... Pump housing, 2 ... Cam ring, 3 ... Rotor, 4 ... Vane, 7 ... Communication path, 11 ... Fluid suction path, 12 ... Fluid discharge path, 15 ... Pump housing inner peripheral surface, 18 ... Pivot recess, 21 ... Cam ring inner peripheral surface, 22 ... Cam ring outer peripheral surface, 23 ... Pivot part, 32 ...
... rotor outer peripheral surface, O ₃ center ...... cam ring, the axis of rotation of the alpha ...... rotor.

Claims (1)

(57) [Claims] 1. A pump housing having a fluid suction passage and a fluid discharge passage, a cam ring provided in the pump housing, a rotor provided in the cam ring and driven to rotate, and a radius around an outer peripheral portion of the rotor. A plurality of vanes provided so as to be able to advance and retreat in the direction, and having a radially outer end slidingly contacting the inner peripheral surface of the cam ring, wherein the cam ring has a center that can be eccentric with respect to the rotation axis of the rotor. The pump housing is swingably supported, and by rotating the rotor, fluid is sucked into the space between the inner peripheral surface of the cam ring and the outer peripheral surface of the rotor through the fluid suction passage. And the discharge amount of the fluid from the fluid discharge passage changes in accordance with the amount of eccentricity of the cam ring. In the displacement type vane pump, a pivot portion is integrally formed on a part of an outer peripheral surface of the cam ring, and a pivot concave portion is formed on a part of an inner peripheral surface of the pump housing. The pivot concave portion is formed on the pivot concave portion. Are rotatably fitted, so that the cam ring is swingably supported, a fluid discharge path is opened in the pivot concave portion, and a pivot portion is provided between the cam ring inner peripheral surface and the rotor outer peripheral surface. A variable displacement vane pump, characterized in that a communication passage is provided for communicating the space portion with the fluid discharge passage.