JP2001263269A - Variable displacement pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure stable relief operation by setting stable relief pressure, and always surely securing a relief passage even if service conditions (a rotating speed and an oil temperature) change when relieving excessive fluid pressure on the pump delivery side in a variable displacement pump. SOLUTION: In this variable displacement pump 10, in the case where a relief valve 70 constitutes a pilot operation type by attaching a pilot valve 72 to a main valve 71, when an end surface 77 of the main valve 71 butts a stopper surface 54A of a second valve chest 73B on the opening operation end of the main valve 71, a communicating passage 78 for keeping communication of a second relief passage 74B opening in the end surface of the second valve chest 73B and the main valve 71 is arranged in at least one of the stopper surface of the second valve chest 73B and the end surface of the main valve 71.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement pump used for a power steering device of an automobile.

[0002]

2. Description of the Related Art Conventionally, a variable displacement pump as disclosed in Japanese Patent Application Laid-Open No. 8-200239 has been proposed in order to assist a steering force in a hydraulic power steering device of an automobile. This conventional variable displacement pump is directly driven to rotate by an engine of an automobile, and a rotor is provided in a cam ring which is displaceably fitted to an adapter ring which is fitted to a pump casing. A pump chamber is formed between the pump chamber and the outer peripheral portion.

In this prior art, the cam ring is movable within the adapter ring, and an urging force for maximizing the volume of the pump chamber is applied to the cam ring by a spring. And a switching valve for moving the cam ring by controlling the supply fluid pressure to the two fluid pressure chambers in accordance with the discharge flow rate of the pressure fluid from the pump chamber. As a result, the discharge flow rate from the pump chamber is controlled by changing the volume of the pump chamber. Thus, in this variable displacement pump, the discharge flow rate is increased so that a large steering assist force is obtained when the vehicle having a low rotation speed is stopped or running at a low speed, and the steering assist force is reduced when the rotation speed is high at a high speed. As described above, the discharge flow rate is controlled to be equal to or less than the predetermined amount, and the steering assist force required for the power steering device can be generated.

Further, in this prior art, when the fluid pressure on the pump discharge side becomes excessive due to, for example, a state in which the steering of the power steering device is kept stationary, a direct acting relief valve for relieving the fluid pressure on the pump discharge side is provided. It is provided in the passage.

[0005]

In the prior art, the relief valve installed in the passage on the pump discharge side is a direct-acting type, and therefore has a large change in relief pressure (pressure override characteristic) depending on the flow rate. The passing flow rate tends to increase as the number of rotations used increases and decrease as the oil temperature decreases. Therefore, the conventional variable displacement pump having a direct acting relief valve is affected by the operating speed and oil temperature,
The originally required relief pressure cannot be obtained.

In the relief valve, a relief path for relieving excessive fluid pressure is always ensured.
It is necessary to ensure a stable relief operation.

SUMMARY OF THE INVENTION An object of the present invention is to set a stable relief pressure in a variable displacement pump in the event of relieving excessive fluid pressure on the pump discharge side, even if the operating conditions (speed, oil temperature) change. Another object of the present invention is to always ensure a relief path to ensure a stable relief operation.

[0008]

According to the first aspect of the present invention, a pump is fixedly mounted on a pump shaft which is inserted into a pump casing, is driven to rotate, and accommodates a large number of vanes in a groove to move in a radial direction. A possible rotor, an adapter ring fitted in the fitting hole of the pump casing, and a pump chamber formed between the adapter ring and the outer peripheral portion of the rotor, and displaceable within the adapter ring. And a cam ring that divides the first and second fluid pressure chambers between the cam ring and the adapter ring, and a pressure difference between a metering orifice provided in a pump discharge side passage and a downstream side of a pumping chamber. By controlling the supply fluid pressure to the first and second fluid pressure chambers according to the discharge flow rate of the pressure fluid from the pump, the cam ring is moved to change the volume of the pump chamber, A switching valve that allows controlling the discharge flow rate from the chamber, the variable displacement pump comprising and a relief valve to relieve excessive fluid pressure at the pump discharge side,
The relief valve has a main valve slidably provided in the valve chamber, and a first valve chamber defined at one end of the valve chamber with respect to the main valve has a fluid upstream of a metering orifice provided in the pump discharge side passage. A first relief which applies pressure to a second valve chamber defined on the other end side of the valve chamber with respect to the main valve, and applies a fluid pressure downstream of the metering orifice to connect the first valve chamber to a drain passage. A first biasing means for providing a passage in the valve chamber, biasing the main valve toward the first valve chamber and setting the main valve to a closed position of the first relief path, wherein the main valve has a second valve chamber; To communicate with the drain passage
A relief valve is provided, and a pilot valve for opening and closing the second relief passage is provided so as to allow only the flow of the fluid from the second valve chamber to the drain passage, and the pilot valve is closed at a relief set pressure to close the second relief passage. A second urging means for setting the pilot valve to the second position by opening the pilot valve against the second urging means by the fluid pressure in the second valve chamber.
When the fluid pressure in the valve chamber is reduced from the second relief passage to the drain passage, and the fluid pressure in the second valve chamber is reduced, the main valve is opposed to the first biasing means by the fluid pressure in the first valve chamber. When the main valve is opened, the fluid pressure in the first valve chamber can be relieved from the first relief passage to the drain passage, and the end surface of the main valve abuts against the stopper surface of the second valve chamber at the opening end of the main valve. At this time, a communication path for maintaining communication between the second valve chamber and the second relief path opened at the end face of the main valve is provided on at least one of the stopper face of the second valve chamber and the end face of the main valve. Things.

According to a second aspect of the present invention, in the first aspect of the present invention, the relief valve is incorporated in the switching valve, and the switching valve is used as a main valve.

According to a third aspect of the present invention, in the first aspect of the present invention, the relief valve is further arranged in parallel with the switching valve.

[0011]

According to the first aspect of the present invention, the following operations are provided. The relief valve installed in the pump discharge side passage was a pilot operated type. Therefore, in this relief valve, the change in relief pressure due to the flow rate (pressure override characteristic)
And a stable relief pressure can be set even if the passing flow rate changes due to changes in use conditions (rotational speed, oil temperature).

Even if the end surface of the main valve abuts against the stopper surface of the second valve chamber at the open operation end of the main valve, the second relief passage opening at the end surface of the main valve is connected to the second valve chamber. The communication with the second valve chamber is maintained through the communication passage without being blocked by the stopper surface (FIG. 6C) (FIGS. 6A and 6B). Therefore, the main valve always reliably secures the relief path and does not adhere to the stopper surface of the second valve chamber. After the relief, the main valve immediately separates from the stopper surface and returns to the original position, and becomes stable. Relief operation can be secured. Since the relief valve operates reliably, protection of the power steering device and the like and safety of steering can be ensured.

According to the second aspect of the present invention, the following operations are provided. A relief valve was incorporated in the switching valve for controlling the movement of the cam ring. Therefore, the passage configuration of the pump casing can be simplified and downsized.

According to the third aspect of the present invention, the following operations are provided. A relief valve was connected in parallel to a switching valve for controlling movement of the cam ring. Therefore, the relief operation of the relief valve does not directly affect the switching operation of the switching valve, and the movement control of the cam ring by the switching valve can be stabilized.

[0015]

FIG. 1 is a sectional view showing a variable displacement pump, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG.
4 is a sectional view taken along the line IV-IV in FIG. 2, FIG. 5 is a hydraulic circuit diagram of the variable displacement pump, and FIG.
Is a schematic diagram showing the main part of the relief valve of the variable displacement pump,
7 is a schematic diagram showing a cap of a relief valve of the variable displacement pump, FIG. 8 is a schematic diagram showing an adapter ring of the variable displacement pump, FIG. 9 is a view along the line IX-IX in FIG. 1, FIG.
Is a schematic diagram showing a cover of the variable displacement pump, and FIG. 11 is a hydraulic circuit diagram showing a modified example of the variable displacement pump.

The variable displacement pump 10 is a vane pump serving as a hydraulic pressure source for a hydraulic power steering device of an automobile. As shown in FIGS.
And a rotor 13 which is fixed by serration to a pump shaft 12 inserted therein and is driven to rotate. The pump casing 11 includes a pump housing 11A and a cover 11A.
B are integrated with bolts 14, and bearings 15A to 15A
The pump shaft 12 is supported via 5C. Pump shaft 1
Numeral 2 can be directly driven to rotate by an automobile engine.

The rotor 13 accommodates vanes 17 in grooves 16 provided at a plurality of positions in the circumferential direction, and enables each vane 17 to move in a radial direction along the grooves 16.

A pressure plate 18 and an adapter ring 19 are fitted in the fitting hole 20 of the pump housing 11A of the pump casing 11 in a stacked state. 11B is fixedly held from the side. One end of the fulcrum pin 21 is attached and fixed to the cover 11B.

A cam ring 22 is fitted to the adapter ring 19 fixed to the pump housing 11A of the pump casing 11. The cam ring 22
The rotor 13 is surrounded by a certain amount of eccentricity with the rotor 13, and the rotor 1 is disposed between the pressure plate 18 and the cover 11 </ b> B.
The pump chamber 23 is formed between the pump chamber 23 and the outer periphery of the pump chamber 3. And
In the suction area on the upstream side in the rotor rotation direction of the pump chamber 23,
A suction port 24 provided in the cover 11B is opened, and a suction port 26 of the pump 10 communicates with the suction port 24 via suction passages 25A and 25B provided in the housing 11A and the cover 11B. On the other hand, a discharge port 27 provided in the pressure plate 18 is opened in a discharge region on the downstream side in the rotor rotation direction of the pump chamber 23, and the discharge port 27 is provided with a high pressure chamber 28 provided in the housing 11A.
A, a discharge port 29 of the pump 10 is communicated through a discharge passage 28B.

Thus, in the variable displacement pump 10, the rotor 13 is driven to rotate by the pump shaft 12,
When the vane 17 of the rotor 13 is rotated by being pressed against the cam ring 22 by centrifugal force, the cam ring 22 and the adjacent vane 17 are located upstream of the pump chamber 23 in the rotor rotation direction.
The working fluid is sucked from the suction port 24 by expanding the volume enclosed by the rotation with the rotation, and the volume surrounded by the adjacent vanes 17 and the cam ring 22 is reduced with the rotation on the downstream side of the pump chamber 23 in the rotor rotation direction to reduce the working fluid. Discharge port 2
7 to discharge.

However, the variable displacement pump 10 has the following
It has a discharge flow control device 40 as shown in (A) and a vane pressurizing device 60 as shown in (B) below.

(A) Discharge flow rate control device 40 The discharge flow rate control device 40 has the above-mentioned fulcrum pin 21 placed on the vertically lowermost portion of the above-mentioned adapter ring 19 fixed to the pump casing 11, and the vertical position of the cam ring 22. The lowermost portion is supported by the fulcrum pin 21, and the cam ring 22 is swingably displaceable within the adapter ring 19.

The discharge flow control device 40 is configured to allow a spring 42 accommodated in a spring chamber 41 provided in a pump housing 11A constituting the pump casing 11 to pass through a spring hole 19A provided in the adapter ring 19, thereby forming an outer peripheral portion of the cam ring 22. To the pump chamber 23
Of the cam ring 22 can be applied to the cam ring 22 so that the volume of the cam ring 22 is maximized. The spring 42 is backed up by a cap 41A screwed into the opening of the spring chamber 41. The adapter ring 19 has a cam ring movement restricting stopper 19B formed in a part of an inner peripheral portion forming a second fluid pressure chamber 44B described later in a convex shape, and a cam ring 22 for minimizing the volume of the pump chamber 23 as described later. Can be restricted. The adapter ring 19 has a cam ring movement restricting stopper 19C formed in a part of an inner peripheral portion forming a first fluid pressure chamber 44A described later in a convex shape, and a cam ring 22 which maximizes the volume of the pump chamber 23 as described later. Can be restricted.

The discharge flow control device 40 has first and second fluid pressure chambers 44A and 44B divided between the cam ring 22 and the adapter ring 19. That is, the first fluid pressure chamber 44A and the second fluid pressure chamber 44B
And the adapter ring 19 are divided by a fulcrum pin 21 and a sealing member 45 provided at an axially symmetric position thereof. At this time, the first and second fluid pressure chambers 44A and 44B cover both sides between the cam ring 22 and the adapter ring 19 with the cover 11.
B and the pressure plate 18, and the above-described cam ring movement restricting stopper 19 of the adapter ring 19.
B, 19C, when the cam ring 22 abuts, the communication grooves 18A connecting the first fluid pressure chambers 44A separated on both sides of the stopper 19C, and the second fluid pressure chambers 44B separated on both sides of the stopper 19B. Is provided on the pressure plate 18.

Here, in the discharge path of the pump 10 described above, the pressure fluid discharged from the pump chamber 23 and discharged from the discharge port 27 of the pressure plate 18 to the high pressure chamber 28A of the pump housing 11A is transferred to the pressure plate 18. From the drilled metering orifice 46, the above-mentioned second fluid pressure chamber 44B, the above-mentioned spring chamber 41 penetrating the adapter ring 19, and the pump housing 1
The pressure is fed to the discharge passage 28B through the discharge communication hole 100 formed by cutting out the fitting hole 20 of 1A.

The discharge flow control device 40 is provided with the pump 1 described above.
In the zero discharge path, the opening area of the metering orifice 46 opening to the second fluid pressure chamber 44B is increased or decreased on the side wall of the cam ring 22 to form a variable metering orifice. That is, the opening of the orifice 46 is adjusted on the side wall thereof in accordance with the displacement of the cam ring 22. And
The discharge flow control device 40 applies the high fluid pressure of the high pressure chamber 28A before passing through the orifice 46 to the first fluid pressure supply path 47A (FIG. 4), the switching valve device 48, the pump housing 11A, and the adapter ring 19. The fluid is guided to the first fluid pressure chamber 44A through the passage 49, and the reduced pressure after passing through the orifice 46 is guided to the second fluid pressure chamber 44B as described above.
4A and 44B, the cam ring 2
2 is moved against the urging force of the spring 42,
The discharge flow rate of the pump 10 can be controlled by changing the volume of the pump chamber 23.

The switching valve device 48 accommodates a spring 52 and a switching valve 53 in a valve storage hole 51 formed in the pump housing 11A.
3 is carried by a cap 54 screwed to the pump housing 11A. The switching valve 53 includes a switching valve body 55A, a valve body 5
5B, the first fluid pressure supply path 47A communicates with the pressurizing chamber 56A of the switching valve body 55A, and the pump housing 11A and the adapter ring 19 are connected to the back pressure chamber 56B in which the other spring 52 of the valve body 55B is stored. The second fluid pressure chamber 44 </ b> B is communicated through a communication passage 57 formed in the second fluid pressure chamber 44. The above-described suction passage (drain passage) 25A is formed through the intermediate chamber 56C between the switching valve body 55A and the valve body 55B,
Contacted tank. The switching valve element 55A is capable of opening and closing the communication path 49 formed in the pump housing 11A and the adapter ring 19. That is, in the low rotation range where the discharge pressure of the pump 10 is low, the switching valve 53 is set to the original position shown in FIG.
5A closes the communication passage 49 with the first fluid pressure chamber 44A,
In the middle and high rotation region of the pump 10, the switching valve 53 is moved by the high-pressure fluid added to the pressurizing chamber 56A to open the communication passage 49, and this high-pressure fluid can be guided to the first fluid pressure chamber 44A.

Accordingly, the discharge flow characteristics of the pump 10 provided with the discharge flow control device 40 are as follows. (1) In the low-speed running range of the vehicle in which the rotation speed of the pump 10 is low, the pressure of the fluid discharged from the pump chamber 23 and reaching the pressurizing chamber 56A of the switching valve device 48 is still low, and the switching valve 53 is in the original position. Then, the cam ring 22 maintains the original state urged by the spring 42. Therefore, the discharge flow rate of the pump 10 increases in proportion to the rotation speed.

(2) As the number of revolutions of the pump 10 increases, the pressure is discharged from the pump chamber 23 and is increased by the pressurizing chamber 56 of the switching valve device 48.
When the pressure of the fluid reaching A increases, the switching valve device 48 moves the switching valve 53 against the urging force of the spring 52 to open the communication passage 49, and the high-pressure fluid is transferred to the first fluid pressure chamber 44A.
Lead to. Thereby, the cam ring 22 is connected to the first fluid pressure chamber 4.
The pump chamber 23 is moved by a pressure difference between the pressure acting on the second fluid pressure chamber 44B and the pressure acting on the second fluid pressure chamber 44B, and the volume of the pump chamber 23 is gradually reduced.
Therefore, the discharge flow rate of the pump 10 can maintain a constant large flow rate by offsetting the increase in the flow rate due to the increase in the number of revolutions and the decrease in the flow rate due to the volume reduction of the pump chamber 23 with respect to the increase in the number of revolutions. it can.

(3) When the number of revolutions of the pump 10 continues to increase and the cam ring 22 further moves, and the cam ring 22 pushes the spring 42 beyond a certain amount, the side wall of the cam ring 22 is The opening area of the orifice 46 in the middle of the discharge path from the nozzle 23 is started to be reduced. Therefore, the discharge flow rate which is pressure-fed to the discharge passage 28B of the pump 10 decreases in proportion to the throttle amount of the orifice 46.

(4) When the rotation speed of the pump 10 reaches a high-speed driving range of the vehicle exceeding a certain value, the cam ring 22 reaches a movement limit where it abuts against the stopper 19 B of the adapter ring 19, and the orifice 46 formed by the side wall of the cam ring 22. The maximum throttle amount also becomes the maximum, and the discharge flow rate of the pump 10 maintains a constant small flow rate.

In the discharge flow control device 40, a throttle 49A is provided in a communication passage 49 for guiding the pressurizing chamber 56A of the switching valve device 48 to the first fluid pressure chamber 44A, and the second fluid pressure chamber 44B is connected to the switching valve device 48. A throttle 57A is provided in a communication path 57 leading to the back pressure chamber 56B.

(B) Vane pressurizing device 60 The vane pressurizing device 60 is provided with the pressure plate 18 and the groove 16 of the side plate 20 corresponding to both sides of the base 16A of the groove 16 accommodating the vane 17 of the rotor 13. Are provided with ring-shaped oil grooves 61 and 62 on the sliding contact surface of the roller. And
The high pressure chamber 28A of the pump chamber 23 provided in the pump housing 11A communicates with the above-described oil groove 61 through an oil hole 63 provided in the pressure plate 18. Accordingly, the pressure fluid discharged from the pump chamber 23 to the high-pressure chamber 28A is transferred to the grooves 16 for all the vanes 17 in the circumferential direction of the rotor 13 through the oil grooves 61 and 62 of the pressure plate 18 and the side plate 20. The vane 17 is guided to the base so that each vane 17 can be pressed toward the cam ring 22.

Thus, in the pump 10, the vane 17 is pressed against the cam ring 22 by centrifugal force at the beginning of rotation, but after the discharge pressure is generated, the vane 17 and the cam ring 22 are The contact pressure is increased, and the backflow of the pressure fluid can be prevented.

In the pump 10, the high pressure chamber 28
A relief valve 70 is provided between A and the suction passage (drain passage) 25A to relieve excessive fluid pressure on the pump discharge side. In the pump 10, a lubricating oil supply passage 121 extending from the suction passage 25B toward the bearing 15C of the pump shaft 12 is formed in the cover 11B, and a lubricating oil return passage 122 returning from around the bearing 15B of the pump shaft 12 to the suction passage 25A. Perforated in the pump housing 11A.

However, in the pump 10, the configuration of the relief valve 70, the configuration of the adapter ring 19, the cover 11
The configuration of B is as follows.

(1) Configuration of Relief Valve 70 (FIGS. 1 to 7) The relief valve 70 is built in the switching valve 53 of the switching valve device 48, and a pilot valve 72 is attached to the main valve 71 from the switching valve 53 itself. It is composed of a pilot operated type. The main valve 71 connects the upstream side passage of the metering orifice 46 provided in the pump discharge side passage, in other words, the first valve chamber (same as the pressurization chamber 56A) 73A to the drain passage 25.
A (suction passage) can be opened and closed. Further, the pilot valve 72 has a fluid pressure downstream of the metering orifice 46 provided in the pump discharge side passage, and thus the cap 5.
The fluid pressure in the second valve chamber 73B (same as the back pressure chamber 56B) 73B defined by the pressure chamber 4 is applied. At this time, the fluid pressure on the downstream side of the metering office 46 is applied to the pilot valve 72 via the throttle 57A of the communication path 57.

Specifically, the relief valve 70 has the following (a)
To (d). (a) The relief valve 70 has a main valve 71 (switching valve 53) slidably provided in a valve chamber 73 (the same as the valve storage hole 51), and a relief valve 70 is provided at one end of the valve chamber 73 with respect to the main valve 71. One valve room 73
The fluid pressure on the upstream side of the metering orifice 46 provided in the discharge side passage of the pump 10 is applied to A (the pressurizing chamber 56A) via the first fluid pressure supply passage 47A. Also, the valve chamber 7
A second valve chamber 73B defined on the other end side of the third main valve 71
(The back pressure chamber 56B) includes the metering orifice 46.
Is applied through the communication passage 57 (throttle 57A). And, the relief valve 70 is connected to the first valve chamber 73A.
Relief passage 74A for connecting the air to the drain passage 25A
(FIG. 5) is provided in the valve chamber 73, and the main valve 71 is connected to the first valve chamber 73A.
Spring 75A (first biasing means, biasing the main valve 71 to the closed position of the first relief path 74A
(Same as the spring 52).

(B) In the relief valve 70, a second relief passage 74B connecting the second valve chamber 73B to the drain passage 25A is provided in the main valve 71, and only the fluid flows from the second valve chamber 73B to the drain passage 25A. So that the second relief path 7
The pilot valve 72 for opening and closing the 4B is connected to the second relief path 7.
4B, a second spring 75B (second urging means) for setting the pilot valve 72 to the closed position (valve seat 76A) of the second relief path 74B with the relief set pressure, and a valve retainer 75C for the main valve 71. It is provided inside.

As shown in FIG. 6, the main valve 71 is integrally provided with a collar 76 for forming a valve seat 76A for the pilot valve 72 inserted and caulked and fixed.
6 has a valve seat 76A and a second relief path 7;
4B is formed. At this time, the collar 76 is inserted into the hole of the main valve 71, and its insertion length is adjusted to an extent that an appropriate spring load corresponding to the relief set pressure can be generated in the second spring 75B for the pilot valve 72. Then, it is caulked and fixed at the caulking part 76B.

(C) The relief valve 70 causes the fluid pressure on the discharge side of the pump to become excessively large due to, for example, the uncontrolled state of steering by the power steering device using the pump 10. When the fluid pressure in the second valve chamber 73B connected to the downstream discharge passage reaches the relief set pressure, the fluid pressure in the second valve chamber 73B causes the pilot valve 72 to open against the second spring 75B. Accordingly, the fluid pressure in the second valve chamber 73B is relieved from the second relief passage 74B to the drain passage 25A, and under the state where the fluid pressure in the second valve chamber 73B is reduced by the relief, the main valve 71 is moved to the first valve chamber. The opening operation is performed against the first spring 75A by the fluid pressure of 73A, and as a result, the fluid pressure of the first valve chamber 73A can be relieved from the first relief passage 74A to the drain passage 25A. This makes it possible to relieve excessive fluid pressure on the pump discharge side.

(D) The relief valve 70 is the main valve 7 of the above (c).
1, the end face 7 of the collar 76 integral with the main valve 71
7 abuts against the stopper surface 54A of the cap 54 defining the second valve chamber 73B. At this time,
In the relief valve 70, as shown in FIGS. 6A and 6B, at least one of the stopper surface 54A of the second valve chamber 73B and the end surface 77 of the main valve 71 has the second valve chamber 73B and the main valve 71B. 7
A communication path 78 for maintaining communication with the second relief path 74 </ b> B provided in FIG. 1 is provided. In the present embodiment, as shown in FIG.
When the short diameter of the recess 79 is smaller than the outer diameter of the end face 77 of the main valve 71 and the long diameter is larger than the outer diameter of the end face 77, and when the end face 77 abuts against the stopper surface 54A, the long diameter of the recess 79 becomes The communication passage 78 is always formed. End face 77 of main valve 71
A notch recess may be provided in a part of the circumferential direction of the above, and when the end surface 77 abuts against the stopper surface 54A, the communication passage 78 may be formed by the notch recess of the end surface 77. Further, the communication passage 78 may be formed by providing a convex portion on at least one of the stopper surface 54A of the second valve chamber 73B and the end surface 77 of the main valve 71.

Therefore, the pump 10 has the following operation by providing the relief valve 70 of the above (1). The relief valve 70 installed in the pump discharge side passage was a pilot operated type. Therefore, in the relief valve 70, a change in the relief pressure (pressure override characteristic) due to the passing flow rate is small, and a stable relief pressure can be set even if the passing flow rate changes due to a change in use conditions (rotational speed, oil temperature).

The relief valve 70 is incorporated in the switching valve 53 for controlling the movement of the cam ring 22. Therefore, the passage configuration of the pump casing 11 can be simplified and downsized.

A throttle 57A is provided in the communication passage 57 for applying a fluid pressure to the pilot valve 72 constituting the relief valve 70. Accordingly, it is possible to avoid a sudden change in the fluid pressure acting on the pilot valve 72 to prevent chattering and prevent noise and vibration of the relief valve 70.

Even if the end surface 77 of the main valve 71 abuts against the stopper surface 54A of the second valve chamber 73B at the opening operation end of the main valve 71, the second relief passage 74 opened at the end surface of the main valve 71.
B is not blocked by the stopper surface 54A of the second valve chamber 73B (FIG. 6C), and communication with the second valve chamber 73B is maintained via the communication passage 57 (FIG. 6A). , (B)).
Therefore, the main valve 71 always ensures the relief path,
There is no adhesion to the stopper surface 54A of the second valve chamber 73B, and after the relief, it is immediately separated from the stopper surface 54A and returns to the original position, and a stable relief operation can be secured. Since the relief valve 70 operates reliably, protection of the power steering device and the like and safety of steering can be ensured.

(2) Configuration of Adapter Ring 19 (FIGS. 2 and 8) In the pump 10, as shown in FIGS.
9 is provided with a slit 80 over the entire area in the width direction. At this time, the outer diameter of the adapter ring 19 is set to be larger than the diameter of the fitting hole 20 in a free state before being fitted into the fitting hole 20 of the pump housing 11A,
From the elastic reduced diameter deformation state equal to or less than the hole diameter of the fitting hole 20 of the pump housing 11A, the fitting is performed in the fitting hole 20 in a state where the elastic diameter increasing behavior that can be in close contact with the fitting hole 20 is provided. Is done. That is, the adapter ring 19 is fitted in the fitting hole 20 with an elastic diameter-reduced deformation state provided. When the fitting is completed, the adapter ring 19 is resiliently expanded in diameter from the elastic diameter-reduced deformation state. In a state of being resiliently pressed into the mounting hole 20 (press-fit state), it is brought into close contact with the fitting hole 20.

At this time, the adapter ring 19 may be provided with the slit 80 in any circumferential direction. For example, the adapter ring 19 may be provided at a position diametrically opposite to the spring hole 19A for the spring 42 described above. In the embodiment, the spring hole 1
A slit 80 is provided at a position crossing 9A.

Further, in the pump 10, FIGS.
As shown in FIG.
The communication paths 81, 82, and 83 that communicate the outer surface portion on the side of 1A with the inner surface portion on the side of the cam ring 22 are connected to the adapter ring 1.
9 is provided in a penetrating manner. At this time, the communication paths 81 to 83
Is a first fluid pressure chamber 44A to which fluid pressure on the upstream side of the metering orifice 46 is supplied in the pump discharge path.
It is communicated to.

Therefore, the pump 10 has the following operation by having the configuration of the adapter ring 19 described in (2) above. At the time of assembling the adapter ring 19 into the pump casing 11, the adapter ring 19 is elastically reduced in diameter due to the presence of the slit 80 and is easily fitted into the fitting hole 20 of the pump casing 11. Good mounting and assemblability can be achieved.

After the adapter ring 19 is fitted and assembled to the pump casing 11, the adapter ring 19 is provided with an elastic diameter-enhancing behavior that comes into close contact with the fitting hole 20 of the pump casing 11. Therefore, when the adapter ring 19 is fitted into the pump casing 11, the adapter ring 19 comes into close contact with the fitting hole 20, and vibration and abnormal noise of the adapter ring 19 during operation of the pump can be reduced.

Since the adapter ring 19 is provided with the slit 80, the adapter ring 19 cannot be firmly pressed into the fitting hole 20 of the pump casing 11, so that the fluid in the fluid pressure chambers 44A, 44B and the like inside the adapter ring 19 can be prevented. Is the slit 80 or the adapter ring 19
The outer surface of the adapter ring 19 and the pump casing 11
The possibility of intrusion during This adapter ring 1
The fluid that has entered between the outer surface of the pump 9 and the pump casing 11 can escape to the inner surface of the adapter ring 19 on the cam ring side through the communication passages 81 to 83. Therefore,
Fluid flows between the outer surface of the adapter ring 19 and the pump casing 1.
When the pump remains operating during the operation of the pump, the fluid may generate a gap between the adapter ring 19 and the pump casing 11, which may cause vibration and abnormal noise. Can be prevented.

The communication paths 81 to 83 of the adapter ring 19
Is connected to the first fluid pressure chamber 44A to which the fluid pressure on the upstream side of the metering orifice 46 is supplied. Since the fluid pressure in the first fluid pressure chamber 44A is high, the adapter ring 1
9 is strongly pressed against the pump casing 11, and the infiltrating fluid on the outer surface of the adapter ring 19 is communicated with the communication passages 81-8.
3 can be reliably squeezed out to the inner diameter portion on the cam ring side.

(3) Configuration of Cover 11B (FIGS. 9 and 10) The pump 10 is connected to the side of the pump housing 11A by bolts 14 and seals the side surfaces of the pump chamber 23 (the rotor 13 and the vane 17). 11B is configured as follows. As shown in FIG. 9, the cover 11B is fixed to the pump housing 11A by five bolts 14A to 14E, and three of the five bolts 14A to 14C are connected to the discharge area side of the pump chamber 23 (from the pump shaft 12). Lower half)
And the two bolts 14D and 14E are connected to the pump chamber 23.
(The upper half of the pump shaft 12).

The cover 11B has ribs 90, 9 on its outer surface.
1 to 95. The rib 90 is provided in a circumferential direction connecting adjacent bolt fixing bosses 90A to 90E on the outer surface of the cover 11B. The ribs 91 to 95 are provided between adjacent bolt fixing bosses 90A to 90E on the outer surface of the cover 11B.
They are provided radially from the center in the radial direction.

Therefore, the pump 10 has the following operation by providing the cover 11B described in (3) above. Five bolts 14A to 14E for fixing the cover 11B to the pump housing 11A are provided, and the bolts 14A to 14E
The number of bolts used is increased by one from the conventional four bolts,
The increase number of 14E was set to the minimum necessary. And three of the five are arranged on the discharge area side of the pump chamber 23 in the cover 11B, in other words, on the side on which a larger pressure acts,
By reducing the span between the fixing portions of the cover 11B by the adjacent bolts 14A to 14E, the bending of the cover 11B was reduced.

In order to increase the rigidity of the cover 11B, ribs 90, 91 to 95 are provided irrespective of the thickness of the cover 11B, which increases the weight of the cover 11B. By providing the ribs 90, 91 to 95 only at the necessary portions without increasing unnecessarily, the rigidity can be improved while reducing the weight of the cover 11B.

Since the ribs 90 are provided in the circumferential direction of the cover 11B, the rigidity between the fixing portions of the adjacent bolts 14A to 14E of the cover 11B can be improved, and the bending of the cover 11B can be reduced.

The ribs 91 to 9 extend in the radial direction of the cover 11B.
5, the rigidity of the cover 11B in the radial direction is improved, and the bending of the cover 11B can be reduced.

As described above, since the bending of the cover 11B can be reduced, the discharge amount decreases due to leakage of fluid pressure from the discharge region to the suction region in the pump chamber 23 covered by the deformed cover 11B, and the groove of the rotor 13 is formed. Cover 11B deforming the smooth movement of the vane 17 provided on the cover 16
Of the pump 10 due to obstruction of the inner surface of the pump 10 and deterioration of discharge efficiency, and generation of abnormal noise due to abnormal contact of the rotor 13 and the vane 17 with the deformed cover 11B can be avoided.

The modification of FIG. 11 differs from that of FIGS. 1 to 10 in that the relief valve 70 is connected to the switching valve 5 of the switching valve device 48.
3, the relief valve 70 is arranged in line with the switching valve 53 of the switching valve device 48.

The relief valve 70 shown in FIG. 11 is of a pilot-operated type in which a pilot valve 72 is attached to a main valve 71, and the main valve 71 is an upstream passage of a metering orifice 46 provided in a pump discharge side passage. In other words, the first valve chamber 73A can be opened and closed with respect to the drain passage 25A. The pilot valve 72 is supplied with the fluid pressure on the downstream side of the metering orifice 46 provided in the pump discharge side passage, and thus the fluid pressure in the second valve chamber 73B. At this time, the fluid pressure on the downstream side of the metering orifice 46 is
0 is applied to the pilot valve 72. The relief valve 70 in FIG. 11 is the same as the relief valve 7 in FIGS.
0 has the following configurations (a) to (c) in the same manner as (a) to (c) described above.

(A) The relief valve 70 has a main valve 71 slidably provided in a valve chamber 73, and a first valve chamber 73A defined at one end of the valve chamber 73 with respect to the main valve 71 has a pump valve 10A. The fluid pressure on the upstream side of the metering orifice 46 provided in the discharge side passage is applied through the passage 131. A second valve chamber 73B defined on the other end side of the valve chamber 73 with respect to the main valve 71 includes:
The fluid pressure downstream of the metering orifice 46 is applied via a passage 132 (throttle 130). The relief valve 70 has a first relief passage 74A that connects the first valve chamber 73A to the drain passage 25A in the valve chamber 73.
The first spring 75 for urging the main valve 71 to the closed position of the first relief path 74A by urging the main valve 71 toward the first valve chamber 73A.
A (first biasing means).

(B) In the relief valve 70, a second relief path 74B connecting the second valve chamber 73B to the drain passage 25A is provided in the main valve 71, and only the fluid flows from the second valve chamber 73B to the drain passage 25A. So that the second relief path 7
The pilot valve 72 for opening and closing the 4B is connected to the second relief path 7.
4B, a second spring 75B (second urging means) for setting the pilot valve 72 to the closed position (valve seat 76A) of the second relief path 74B with the relief set pressure, and a valve retainer 75C for the main valve 71. It is provided inside.

(C) The relief valve 70 causes the fluid pressure on the discharge side of the pump to become excessively large due to, for example, the continued steering state of the power steering device using the pump 10, causing the relief of the metering orifice 46. When the fluid pressure in the second valve chamber 73B connected to the downstream discharge passage reaches the relief set pressure, the fluid pressure in the second valve chamber 73B causes the pilot valve 72 to open against the second spring 75B. Accordingly, the fluid pressure in the second valve chamber 73B is relieved from the second relief passage 74B to the drain passage 25A, and under the state where the fluid pressure in the second valve chamber 73B is reduced by the relief, the main valve 71 is moved to the first valve chamber. The opening operation is performed against the first spring 75A by the fluid pressure of 73A, and as a result, the fluid pressure of the first valve chamber 73A can be relieved from the first relief passage 74A to the drain passage 25A. This makes it possible to relieve excessive fluid pressure on the pump discharge side.

According to the relief valve 70 shown in FIG. 11, the relief valve 70 is arranged in parallel with the switching valve 53 for controlling the movement of the cam ring 22. Therefore, the relief operation of the relief valve 70 does not directly affect the switching operation of the switching valve 53, and the movement control of the cam ring 22 by the switching valve 53 can be stabilized.

The relief valve 70 shown in FIG.
At the open operation end of the main valve 71, the end face of the main valve 71 is in the second valve chamber 73B.
The second valve chamber 73B and the main valve 7
A communication passage 78 that keeps the second relief passage 74B open at one end face can be provided on at least one of the stopper face of the second valve chamber 73B and the end face of the main valve 71. According to this, a relief path can always be reliably secured in the relief valve 70, and a stable relief operation can be secured.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration of the present invention is not limited to the embodiments, and the design may be changed without departing from the scope of the present invention. The present invention is also included in the present invention.

[0069]

As described above, according to the present invention, in the variable displacement pump, when the excessive fluid pressure on the pump discharge side is relieved, the pump becomes stable even if the use conditions (rotational speed, oil temperature) change. In addition to setting the relief pressure, a stable relief operation can be secured by always ensuring the relief path.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a variable displacement pump.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a sectional view taken along the line III-III of FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 2;

FIG. 5 is a hydraulic circuit diagram of the variable displacement pump.

FIG. 6 is a schematic view showing a main part of a relief valve of the variable displacement pump.

FIG. 7 is a schematic view showing a cap of a relief valve of the variable displacement pump.

FIG. 8 is a schematic view showing an adapter ring of the variable displacement pump.

FIG. 9 is a view along the line IX-IX in FIG. 1;

FIG. 10 is a schematic view showing a cover of the variable displacement pump.

FIG. 11 is a hydraulic circuit diagram showing a modification of the variable displacement pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Variable displacement pump 11 Pump casing 12 Pump shaft 13 Rotor 16 Groove 17 Vane 19 Adapter ring 20 Fitting hole 22 Cam ring 23 Pump chamber 25A Drain passage (suction passage) 44A First fluid pressure chamber 44B Second fluid pressure chamber 46 Mailing Orifice 48 Switching valve device 53 Switching valve 54A Stopper surface 57A Restrictor 70 Relief valve 71 Main valve 72 Pilot valve 73A First valve chamber 73B Second valve chamber 74A First relief path 74B Second relief path 75A First spring (first attachment) Urging means) 75B second spring (second urging means) 77 end face 78 communicating passage

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 18, 2000 (2004.1.
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction contents]

(B) The relief valve 70 is connected to the second relief passages 74B and 74 connecting the second valve chamber 73B to the drain passage 25A.
4C is provided on the main valve 71, and the pilot valve 72 for opening and closing the second relief passages 74B and 74C is configured to allow only the flow of the fluid from the second valve chamber 73B to the drain passage 25A . 74C , the pilot valve 72 is set to the second relief path 74B , 7B at the relief set pressure.
A second spring 75B (second urging means) set at the closed position (valve seat 76A) of 4C and a valve presser 75C are provided inside the main valve 71.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

(C) The relief valve 70 causes the fluid pressure on the discharge side of the pump to become excessively large due to, for example, the uncontrolled state of steering by the power steering device using the pump 10. When the fluid pressure in the second valve chamber 73B connected to the downstream discharge passage reaches the relief set pressure, the fluid pressure in the second valve chamber 73B causes the pilot valve 72 to open against the second spring 75B. Accordingly, the fluid pressure in the second valve chamber 73B is relieved from the second relief passages 74B and 74C to the drain passage 25A, and the main valve 71 is moved to the first position under the state where the fluid pressure in the second valve chamber 73B is reduced by the relief. The opening operation is performed against the first spring 75A by the fluid pressure of the valve chamber 73A, and as a result, the fluid pressure of the first valve chamber 73A can be relieved from the first relief passage 74A to the drain passage 25A. This makes it possible to relieve excessive fluid pressure on the pump discharge side.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0064

[Correction method] Change

[Correction contents]

(B) The relief valve 70 has the second relief passages 74B , 7B connecting the second valve chamber 73B to the drain passage 25A.
4C is provided on the main valve 71, and the pilot valve 72 for opening and closing the second relief passages 74B and 74C is configured to allow only the flow of the fluid from the second valve chamber 73B to the drain passage 25A . 74C , the pilot valve 72 is set to the second relief path 74B , 7B at the relief set pressure.
A second spring 75B (second urging means) set at the closed position (valve seat 76A) of 4C and a valve presser 75C are provided inside the main valve 71.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0065

[Correction method] Change

[Correction contents]

(C) The relief valve 70 causes the fluid pressure on the discharge side of the pump to become excessively large due to, for example, the continued steering state of the power steering device using the pump 10, causing the relief of the metering orifice 46. When the fluid pressure in the second valve chamber 73B connected to the downstream discharge passage reaches the relief set pressure, the fluid pressure in the second valve chamber 73B causes the pilot valve 72 to open against the second spring 75B. Accordingly, the fluid pressure in the second valve chamber 73B is relieved from the second relief passages 74B and 74C to the drain passage 25A, and the main valve 71 is moved to the first position under the state where the fluid pressure in the second valve chamber 73B is reduced by the relief. The opening operation is performed against the first spring 75A by the fluid pressure of the valve chamber 73A, and as a result, the fluid pressure of the first valve chamber 73A can be relieved from the first relief passage 74A to the drain passage 25A. This makes it possible to relieve excessive fluid pressure on the pump discharge side.

[Procedure amendment 5]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

[Procedure amendment 6]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6

[Procedure amendment 7]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 11

Continued on the front page (72) Inventor Yoshiya Hano 112-1 Hagadai, Haga-cho, Haga-gun, Tochigi F-term in Showa Tochigi Development Center Co., Ltd. (Reference) 3H040 AA03 BB01 BB11 CC10 CC15 CC16 CC18 CC19 CC20 CC21 CC22 DD01 DD21 DD26 DD33 DD40 3H044 AA02 BB05 CC11 CC14 CC19 CC22 DD10 DD11 DD14 DD28 DD35 DD42

Claims (3)

[Claims] A rotor rotatably driven by being fixed to a pump shaft inserted into a pump casing and capable of moving a plurality of vanes in a groove so as to be movable in a radial direction, and fitted into a fitting hole of the pump casing. A pump chamber is formed between the adapter ring to be mounted and the adapter ring, and the pump chamber is formed between the adapter ring and the outer periphery of the rotor.
And a cam ring which divides the second fluid pressure chamber and a first fluid pressure chamber. The first fluid pressure chamber is actuated by a pressure difference between a pressure above and a downstream of a metering orifice provided in a pump discharge side passage. And a control valve for controlling the supply fluid pressure to the second fluid pressure chamber to change the volume of the pump chamber by moving the cam ring to control the discharge flow rate from the pump chamber. A relief valve for relieving an excessive fluid pressure of the variable displacement pump, wherein the relief valve is provided with a main valve slidably in a valve chamber, and the relief valve is provided on one end side of the valve chamber with respect to the main valve. The fluid pressure on the upstream side of the metering orifice provided in the pump discharge side passage is applied to one valve chamber,
A fluid pressure downstream of the metering orifice is applied to a second valve chamber defined on the other end side of the valve chamber with respect to the main valve, and a first relief path connecting the first valve chamber to the drain passage is provided in the valve chamber. A first urging means for urging the main valve toward the first valve chamber to set the main valve at the closed position of the first relief passage, wherein the main valve communicates the second valve chamber with the drain passage. And a pilot valve for opening and closing the second relief passage so as to allow only the flow of the fluid from the second valve chamber to the drain passage. A second urging means for setting the path to a closed position, wherein the pilot valve is opened against the second urging means by the fluid pressure of the second valve chamber, thereby increasing the fluid pressure of the second valve chamber. Fluid pressure in the second valve chamber due to relief from the relief passage to the drain passage In the reduced state, the main valve is opened against the first urging means by the fluid pressure of the first valve chamber, whereby the fluid pressure of the first valve chamber can be relieved from the first relief passage to the drain passage. When the end face of the main valve abuts against the stopper face of the second valve chamber at the open operation end of the main valve, a communication path for maintaining communication between the second valve chamber and the second relief path opened at the end face of the main valve. Is provided on at least one of the stopper surface of the second valve chamber and the end surface of the main valve. 2. The variable displacement pump according to claim 1, wherein said relief valve is built in said switching valve, and said switching valve is used as a main valve. 3. The variable displacement pump according to claim 1, wherein said relief valve is arranged in parallel with said switching valve.