JPH084665A - Variable displacement type vane pump - Google Patents

Abstract

PURPOSE:To prevent hydraulic vibration from occurring completely by forming a braking means which brakes a cam ring by adding prescribed pressure for preventing the cam ring from hunting without need for any space with a simple constitution when the hydraulic vibration of the cam ring occurs. CONSTITUTION:Driving force is given to a rotor 15 by driving the rotation of a rotating shaft, and at the time of operating a pump with a cam ring 2 kept eccentric, oil is sucked from an intake port 20, and a chamber which is surrounded by a vane 17, the cam ring 2, the rotor 15, a pump housing 1 and a pump cover is filled with the oil. While an oil chamber is being transferred to the discharge port 21 side through its top dead center from the intake port 20 side, pump action is given by a chamber volume change, and pressure oil is discharged to the discharge port 21. A part of discharge pressure is led to the back surface of a friction ring 23 through an introduction oil passage 24, and the friction ring 23 is pressed against the inner end surface 1a of the pump housing 1 to increase sliding resistance while the cam ring 2 is sliding, thus preventing hydraulic vibration from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement vane pump adapted to an automatic transmission for automobiles and the like.

[0002]

2. Description of the Related Art Conventionally, a pump shown in FIG. 14 is known as a variable displacement vane pump adapted to an automatic transmission for an automobile. This conventional pump has a rotary drive shaft 50.
And a plurality of vanes 52 movably supported by the rotor 51 in a radial direction, and a vane sliding cylindrical surface 53 with which tip ends of the vanes 52 slide. The cam ring 54 movably supported in the pump housing 56 within a predetermined range in which the center of the contact cylindrical surface 53 is eccentric from the center of the rotor 51, and one side surface of each of the rotor 51, the vane 52, and the cam ring 54 is covered. At the same time, the pump cover 5 has a suction port hole and a discharge port hole (both not shown) formed therein.
Pumps with 5 and 5 are known.

In such a variable displacement vane pump and the hydraulic circuit structure thereof, hydraulic vibration is likely to occur due to hunting of the cam ring 54. This hydraulic vibration is shown in FIG. However, this FIG. 18 shows the case where there is no accumulator in the hydraulic circuit configuration.

As a means for preventing the occurrence of hydraulic vibration due to hunting of the cam ring 54, a ring groove 57 is formed in a side surface portion 54a of the cam ring 54 which faces the inner end surface 56a of the pump housing 56, as shown in FIG. Then, the O-ring 58 and the friction ring 59 are accommodated in the ring groove 57, and the friction ring 59 is pressed against the inner end surface 56a of the pump housing 56 by the deformation of the O-ring 58. Sliding resistance is added to prevent hydraulic vibration.

As a means for preventing the occurrence of hydraulic vibration, a feedback accumulator 61 and a bleed orifice 62 are provided in the feedback circuit 60 of the hydraulic circuit of the variable displacement vane pump as shown in FIG. Japanese Patent Laid-Open No. 4-194
391 and Japanese Patent Laid-Open No. 3-2799687.

The technique disclosed in Japanese Patent Laid-Open No. 3-194181 is to prevent hunting of the cam ring by interposing a dynamic damper between the pump wall and the outer periphery of the cam ring in the moving direction of the cam ring which is moved when adjusting the discharge flow rate. In the disclosed technique of Japanese Patent Laid-Open No. 3-194181, the base end of the return spring that bears the swing of the cam ring is brought into contact with a ram member that is movable in the expansion and contraction direction of the return spring, By connecting the back pressure chamber to the discharge port, it is possible to control the pump discharge flow rate in proportion to the regulator pressure.

Further, in the technique disclosed in Japanese Patent Laid-Open No. 3-279687, the pressure chamber behind the piston member, which abuts on the outer peripheral surface of the cam ring, is communicated with the pump chamber on the opposite side with the cam ring interposed therebetween, and the biasing chamber acts on the cam ring. Control the load,
This is to prevent hunting.

[0008]

However, as shown in FIG.
By the deformation of the O-ring 58 as shown in FIG.
6A is not effective because it has a small sliding resistance when the cam ring 54 swings, and a feedback accumulator 61 and a bleed orifice 62 are provided in the feedback circuit 60 of the hydraulic circuit of the variable displacement vane pump. Japanese Patent Laid-Open No. 3-194181, Japanese Patent Laid-Open No. 4-194391, and Japanese Patent Laid-Open No. 3-2.
In each of the ones disclosed in Japanese Patent No. 79687, a separate circuit for preventing the occurrence of hydraulic vibration and a separate component are required, so that the structure is complicated, the required space is increased, and the cost is increased. There was a problem.

The present invention has been made in view of the above problems, and its purpose is to prevent hunting of a cam ring with a simple structure and without requiring a space. Another object of the present invention is to provide a variable displacement vane pump that is capable of reliably preventing the occurrence of hydraulic vibration.

[0010]

In order to achieve the above object, the present invention has a vane sliding contact cylindrical surface with which the tips of a plurality of vanes slidably supported by a rotationally driven rotor are in sliding contact. And a variable capacity provided with a cam ring movably supported in the housing within a predetermined range in which the center of the vane sliding cylindrical surface is eccentric from the center of the rotor, and means for rocking the cam ring by feedback pressure. The type vane pump is characterized by comprising braking means for braking the cam ring by applying a predetermined pressure when hydraulic vibration of the cam ring occurs.

The predetermined pressure is preferably the discharge pressure. Further, it is preferable to apply a predetermined pressure through a check valve. Further, it is preferable that the predetermined pressure is a feedback pressure. Further, it is preferable that the means for rocking the cam ring by the feedback pressure is a control piston.

Further, it is preferable that the braking means is a friction ring provided on the cam ring and in sliding contact with the end surface of the housing. Further, it is preferable that the braking means is a seal member provided on the control piston and in sliding contact with an end surface of the housing.

[0013]

With this structure, the braking means operates by applying a predetermined pressure to prevent hydraulic vibration. When this hydraulic vibration subsides, the braking force also decreases. That is, the hunting of the cam ring is prevented by increasing or decreasing the braking force when the cam ring swings according to the state of occurrence of hydraulic vibration.

When the braking means is a friction ring provided on the cam ring and slidably contacting the end surface of the housing, a part of the discharge pressure is guided to the rear surface of the friction ring, and the friction ring is connected to the housing. Pressing against the end face increases the sliding resistance when the cam ring swings and prevents hydraulic vibration. When this hydraulic vibration subsides, the pressing force of the friction ring also decreases and returns to the normal pressing force. That is, the sliding resistance when the cam ring swings is increased or decreased according to the state of occurrence of hydraulic vibration to prevent cam ring hunting.

When the braking means is a seal member provided on the control piston and slidingly contacting the end face of the housing, the feedback pressure is guided to the rear face of the piston seal when hydraulic vibration occurs, and the cam ring swings. Prevents hydraulic vibration by increasing sliding resistance during movement.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a vertical sectional view of an embodiment (Embodiment 1) of a variable displacement vane pump according to the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 4 is a sectional view taken along line BB in FIG. 4, and FIG. 4 is a view taken in the direction of the arrow C in FIG.

The variable displacement vane pump according to the present invention comprises a housing M, which comprises a pump housing 1 and a pump cover 19. A cam ring 2 is housed in the pump housing 1. The cam ring 2 has a vane-sliding cylindrical surface 2a on its inner peripheral portion.
Further, a supporting portion 3 and a spring receiving portion 4 located on the opposite side of the supporting portion 3 are formed on the outer peripheral portion thereof. The cam ring 2 is attached to the pump housing 1 so as to be swingable by a pivot pin 5 in the supporting portion 3 within a predetermined range in which the center of the vane sliding contact cylindrical surface 2a is eccentric from the center of the rotor described later. A return spring 7 is interposed between the spring receiving portion 4 and the spring receiving portion 6 provided on the inner surface of the pump housing 1.

In the pump housing 1, a control piston 8 is provided with a pivot pin 9 at its right end.
The control piston 8 is provided with a pressing protrusion 10 at an intermediate portion thereof, and the pressing protrusion 10 is in contact with the protrusion 11 on the outer peripheral portion of the cam ring 2. An oil chamber 12 is formed in the pump housing 1 so as to be positioned behind the control piston 8. Therefore, the eccentricity of the cam ring 2 is performed by operating the control piston 8 by the hydraulic control of the oil chamber 12. A feedback pressure in which a part of the discharged oil is controlled by a pressure regulator valve (not shown) is introduced into the oil chamber 12 via a feedback pressure oil passage 27.

A rotor 15 is splined to the rotary drive shaft 14. This rotor 15 has a vane groove 1
6 is formed in a radial shape, and a vane ring 18 that regulates the inner position of the vane 17 is formed, and the vane 17 is inserted in the vane groove 16 of the rotor 15 so as to be retractable. The tips of the vanes 17 are in sliding contact with the vane sliding contact cylindrical surface 2a of the cam ring 2.

A pump cover 19 is attached to the end of the pump housing 1 to cover one side of the rotor 15, the vane 17, and the cam ring 2. Further, 20 is an intake port, and 21 is a discharge port.

A ring groove 22 is formed in a circumferential direction on a side surface portion 2a of the cam ring 2 facing the inner end surface 1a of the pump housing 1, and an O ring 22a and a friction ring 23 are formed in the ring groove 22. Housed,
The friction ring 23 is the pump housing 1
Is in contact with the inner end surface 1a of the cam ring 2 to prevent oil leakage from the side surface of the cam ring 2.

Further, the cam ring 2 is formed with an introduction oil passage 24 for guiding the discharge pressure to the rear surface of the friction ring 23. The introduction oil passage 24 is composed of an oil groove 25 formed in the side surface 2 a of the cam ring 2 in the radial direction and an oil groove 26 formed in the inner peripheral surface of the ring groove 22. The introduction oil passage 24 and the friction ring 23 constitute a braking means.

Next, the operation will be described. The rotary drive shaft 1
When the pump is operated in a state where the cam ring 2 is eccentric, oil is sucked from the suction port 20 and the vane 1
7, the chamber surrounded by the cam ring 2, the rotor 15, the pump housing 1 and the pump cover 19 is filled with oil, and while the oil chamber moves from the suction port 20 side to the discharge port 21 side after passing the top dead center, the chamber is filled with oil. The pressure oil is discharged to the discharge port 21 due to the pumping action due to the volume change.

In this case, a part of the discharge pressure is introduced into the introduction oil passage 2
4 is guided to the rear surface of the friction ring 23, and the friction ring 23 is connected to the pump housing 1
It is pressed against the inner end face 1a of the cam ring 2 to increase the sliding resistance when the cam ring 2 swings to prevent hydraulic vibration. When this hydraulic vibration subsides, the pressing force of the friction ring 23 also decreases and returns to the normal pressing force. That is, hunting of the cam ring 2 is prevented by increasing or decreasing the sliding resistance when the cam ring 2 swings according to the state of occurrence of hydraulic vibration. The reduction of hydraulic vibration is shown in FIG. FIG. 13 (1) is a waveform of the hydraulic vibration when the discharge pressure is not applied to the back surface of the friction ring 23, and FIG. 13 (2) is a hydraulic vibration when the discharge pressure is applied to the back surface of the friction ring 23. Is the waveform of.

When a discharge pressure is applied to the back surface of the friction ring 23, the discharge pressure becomes high, and when the oil leak from the side surface of the cam ring 2 increases, the sealing performance of the friction ring 23 is increased. And the pump efficiency is improved.

(Embodiment 2) This embodiment is shown in FIGS. In the case of this embodiment, the introduction oil passage 24 for guiding the discharge pressure to the rear surface of the friction ring 23 is constituted by an oil hole 30 provided in the cam ring 2, and a ball 31 and a spring 32 are provided in the middle of the oil hole 30. A check valve T, which is urged to seat on the valve seat 33, is provided. Normally, the ball 31 is seated on the valve seat 33 so that only the sliding resistance of the cam ring 2 due to the pressing of the O ring 22a is provided. When the hydraulic vibration is generated, the discharge pressure is applied to the ball 31, the ball 31 is separated from the valve seat 33, the check valve T is opened, the discharge pressure is guided to the rear surface of the friction ring 23, and the cam ring 2 swings. The sliding resistance at that time is increased to prevent the occurrence of hydraulic vibration. The other structure is the same as that of the first embodiment.

(Embodiment 3) This embodiment is shown in FIGS.
Shown in In the case of this embodiment, the pump housing 1
From the feedback pressure oil passage 27 formed in
The feedback pressure is guided to the back surface of the friction ring 23 via the. Then, the introduction oil passage 35 communicates with the feedback pressure oil passage 27 to the support portion 36 of the pivot pin 5, an oil hole 37 provided in the center portion of the pivot pin 5, and the cam ring 2. The oil hole 40 extends from the pivot pin support hole 39 to the rear surface of the friction ring 23, and the swivel joint 41 connects the oil hole 38 and the oil hole 40. Further, the other structure is the same as that of the above-described first embodiment.

Therefore, when the hydraulic vibration is generated, the feedback pressure is guided to the rear surface of the friction ring 23 through the introduction oil passage 35 to increase the sliding resistance when the cam ring 2 swings to generate the hydraulic vibration. To prevent.

(Embodiment 4) This embodiment is shown in FIGS.
It is shown in FIG. In the case of this embodiment, a concave groove 42 is formed in a side surface portion 8a of the control piston 8 facing the inner end surface of the pump cover 19, and a piston seal 43 is housed in the concave groove 42. An inlet oil passage 44 for guiding a feedback pressure to the back surface of the piston seal 43 is formed in the portion, and the other structure is the same as that of the first embodiment.

Therefore, when the hydraulic vibration is generated, the feedback pressure is guided to the rear surface of the piston seal 43 through the introduction oil passage 44 to increase the sliding resistance when the cam ring 2 swings to generate the hydraulic vibration. To prevent.

[0031]

As described above, according to the present invention, the vane-sliding cylinder has the vane-sliding cylinder surface with which the tips of the vanes slidably supported by the rotationally driven rotor are in sliding contact. A variable displacement vane pump comprising a cam ring movably supported in a housing within a predetermined range in which a center of a surface is eccentric from a center of the rotor, and a means for swinging the cam ring by a feedback pressure. Since the braking means for braking the cam ring by applying a predetermined pressure when the hydraulic vibration occurs is provided, the braking means operates by applying the predetermined pressure to prevent the hydraulic vibration from occurring. When this hydraulic vibration subsides, the braking force also decreases. That is, the hunting of the cam ring can be prevented by increasing or decreasing the braking force when the cam ring swings according to the state of occurrence of hydraulic vibration. As described above, it is possible to prevent the hunting of the cam ring with a simple structure and without requiring a space, and it is possible to reliably prevent the occurrence of hydraulic vibration.

When the braking means is a friction ring provided on the cam ring and slidingly contacting the end face of the housing, a part of the discharge pressure or the feedback pressure is guided to the rear surface of the friction ring, This friction ring is pressed against the end surface of the housing to increase the sliding resistance when the cam ring swings and prevent the occurrence of hydraulic vibration. When this hydraulic vibration subsides, the pressing force of the friction ring also decreases, returning to the normal pressing force. That is, the hunting of the cam ring can be prevented by increasing or decreasing the sliding resistance when the cam ring swings according to the state of occurrence of hydraulic vibration. Further, when the discharge pressure is applied to the back surface of the friction ring, the discharge pressure increases, and when the oil leak from the side surface of the cam ring increases, the sealing performance of the friction ring improves and the pump efficiency increases. Is improved.

Further, when the means for oscillating the cam ring by the feedback pressure is a control piston and the braking means is a seal member provided on the control piston and slidingly contacting the end face of the housing, hydraulic vibration is generated. It is possible to prevent the occurrence of hydraulic vibration by guiding the feedback pressure to the back surface of the piston seal when the above occurs and increasing the sliding resistance when the cam ring swings.

Further, by applying a predetermined pressure through the check valve, the check valve is normally closed and only the sliding resistance of the cam ring is provided, and when the hydraulic vibration occurs, the discharge pressure is checked. By opening the valve, the discharge pressure can be guided to the back surface of the friction ring, and the sliding resistance when the cam ring swings can be increased to prevent hydraulic vibration from occurring.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment (embodiment 1) of a variable displacement vane pump according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

3 is a cross-sectional view taken along the line BB of FIG.

FIG. 4 is a view from the direction C in FIG.

FIG. 5 is a vertical cross-sectional view of another embodiment (Example 2) of the variable displacement vane pump according to the present invention.

6 is a cross-sectional view taken along the line DD of FIG.

7 is a cross-sectional view taken along the line EE of FIG.

FIG. 8 is a side view of the variable displacement vane pump according to another embodiment of the present invention with the pump cover removed, which is another embodiment (Embodiment 3).

9 is a sectional view taken along the line FF of FIG.

FIG. 10 is a vertical sectional view of another embodiment (Example 4) of the variable displacement vane pump according to the present invention.

11 is a cross-sectional view taken along the line GG of FIG.

12 is a cross-sectional view taken along the line HH of FIG.

FIG. 13 (1) is a diagram of hydraulic vibration when the discharge pressure is not applied to the back surface of the friction ring. (2) is a diagram of hydraulic vibration when a discharge pressure is applied to the back surface of the friction ring.

FIG. 14 is a vertical cross-sectional view of a conventional variable displacement vane pump.

15 is a cross-sectional view taken along the line I-I of FIG.

FIG. 16 is an enlarged detailed view of a J portion in FIG.

FIG. 17 is an explanatory diagram of a circuit configuration of a conventional variable displacement vane pump.

FIG. 18 is a diagram of hydraulic vibration due to hunting of a conventional cam ring.

[Explanation of symbols]

 2 Cam ring 2a Vane sliding contact cylindrical surface 8 Control piston 15 Rotor 17 Vane 23 Friction ring M Housing

Claims (7)

[Claims] Claim: What is claimed is: 1. A vane sliding contact cylindrical surface with which tip ends of a plurality of vanes supported by a rotor driven to rotate are slidably contacted, and the center of the vane sliding contact cylindrical surface is eccentric from the center of the rotor. In a variable displacement vane pump equipped with a cam ring movably supported in the housing within a predetermined range and means for swinging the cam ring by feedback pressure, when a hydraulic vibration of the cam ring occurs, a predetermined pressure A variable displacement vane pump characterized by comprising braking means for additionally braking said cam ring. 2. The variable displacement vane pump according to claim 1, wherein the predetermined pressure is a discharge pressure. 3. The variable displacement vane pump according to claim 1, wherein the predetermined pressure is applied through a check valve. 4. The variable displacement vane pump according to claim 1, wherein the predetermined pressure is a feedback pressure. 5. The variable displacement vane pump according to claim 1, wherein the means for rocking the cam ring by the feedback pressure is a control piston. 6. The variable displacement vane pump according to claim 1, wherein the braking means is a friction ring which is provided on the cam ring and is in sliding contact with the end surface of the housing. 7. The variable displacement vane pump according to claim 5, wherein the braking means is a seal member provided on the control piston and slidingly contacting an end surface of the housing.