JP2001065470A - Variable displacement pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce vibration and noise from an adapter ring in operation of a pump while the fitting installation of the adapter ring into a pump casing is assured in a variable displacement pump. SOLUTION: This variable displacement pump 10 comprises fluid pressure communicating paths 49 and 57 leading from the side of a pump casing 11 through an adapter ring 19 to a first fluid pressure chamber 44A or a second fluid pressure chamber 44B. In this case, O-rings 71 and 72 surrounding the communicating paths 49 and 57 are provided between the adapter ring 19 and the pump casing 11.

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. The first and second fluid pressure chambers are formed separately, and the cam ring is moved against the urging force by the differential pressure of the pressure acting on both fluid pressure chambers, and the discharge flow rate is changed by changing the volume of the pump chamber. It has a controllable discharge flow rate control device. 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.

[0004]

However, in the prior art, the adapter ring is annular, and when the adapter ring is fitted to the pump casing, it cannot be press-fit because the adapter ring is a thin-walled material. For this reason, when the adapter ring is fitted into the pump casing, it is unavoidable to have a slight gap between the adapter ring and the pump casing, and the existence of this gap causes unnecessary vibration of the adapter ring at the time of operation of the pump. It may cause sound.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the occurrence of vibration and abnormal noise of an adapter ring during operation of a pump in a variable displacement pump while improving the fitting and assembling properties of the adapter ring to a pump casing. is there.

[0006]

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, a cam ring fitted in the adapter ring and forming a pump chamber between the outer periphery of the rotor, and a cam ring in the adapter ring A biasing force is applied to the cam ring so that the displacement is possible and the volume of the pump chamber is maximized, and first and second fluid pressure chambers are formed separately between the cam ring and the adapter ring. A discharge flow control device that moves the cam ring against the urging force by a pressure difference acting on the chamber to change the volume of the pump chamber to control the discharge flow rate. In the variable displacement pump, a communication path for fluid pressure is provided from the pump casing side to the first or second fluid pressure chamber through the adapter ring, and the communication path is surrounded between the adapter ring and the pump casing. O
The ring is interposed.

[0007]

According to the first aspect of the present invention, the following effects are obtained. The adapter ring is easily fitted into the fitting hole of the pump casing while elastically deforming the O-ring at the time of fitting and assembling to the pump casing, so that fitting and assembling property can be improved.

After the adapter ring is fitted to the pump casing, an O-ring is interposed between the pump casing and the pump casing in a state of being pressed, so that vibration and abnormal noise of the adapter ring during operation of the pump are reduced. it can.

[0009] The machining accuracy of the fitting hole of the pump casing,
With a simple configuration using only an O-ring without increasing the processing accuracy of the outer peripheral surface of the adapter ring, it is possible to reduce the vibration and abnormal noise of the adapter ring during the operation of the pump.

Since the communication path for the fluid pressure from the pump casing to the adapter ring is surrounded by the O-ring between the adapter ring and the pump casing, leakage of the fluid pressure from the communication path can be prevented, and the control accuracy can be improved.

[0011]

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. 3 is a schematic view showing an adapter ring.

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 number of positions in the circumferential direction, and allows each vane 17 to move radially 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, and these are covered in a state where they are positioned in a circumferential direction by a fulcrum pin 21 described later. 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 on the adapter ring 19 fixed to the pump casing 11. The cam ring 22 surrounds the rotor 13 with a certain amount of eccentricity with the rotor 13, and forms a pump chamber 23 between the pressure plate 18 and the cover 11 </ b> B and the outer periphery of the rotor 13. A suction port 24 provided in the cover 11B is provided upstream of the pump chamber 23 in the rotor rotation direction.
Is opened, and the suction port 24 has a housing 11A,
A suction port 26 of the pump 10 communicates with suction passages 25A and 25B provided in 11B. On the other hand, a discharge port 27 provided in the pressure plate 18 is opened downstream of the pump chamber 23 in the direction of rotor rotation, and the discharge port 27 is provided with a high pressure chamber 28 provided in the housing 11A.
A, a discharge port 29 (not shown) of the pump 10 is communicated via a discharge passage 28B (not shown).

Thus, in the variable displacement pump 10, the rotor 13 is driven to rotate by the pump shaft 12,
When the vanes 17 of the rotor 13 are rotated by being pressed against the cam ring 22 by centrifugal force, the cam ring 22 and the adjacent vanes 17 are located downstream 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 upstream side in the rotor rotation direction of the pump chamber 23 to reduce the working fluid. Discharge port 2
7 to discharge.

However, the variable displacement pump 10 has the following construction.
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 control device 40 The discharge flow control device 40 mounts the above-mentioned fulcrum pin 21 on the vertically lowermost portion of the above-described adapter ring 19 fixed to the pump casing 11 and moves the lowermost portion of the cam ring 22 vertically. The cam ring 22 is supported by the fulcrum pin 21 so as to be capable of swinging displacement within the adapter ring 19.

The discharge flow control device 40 allows the spring 42 accommodated in the spring chamber 41 provided in the pump housing 11A constituting the pump casing 11 to pass through the spring hole 19A provided in the adapter ring 19, and the outer peripheral portion of the cam ring 22 is provided. 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 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.

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. The above-mentioned second fluid pressure chamber 44B, the above-mentioned spring chamber 41 penetrating the adapter ring 19, and the discharge communication hole (not shown) formed in the fitting hole 20 of the pump housing 11A from the drilled orifice 46. ) To the discharge passage 28B.

The discharge flow control device 40 is provided with the pump 1 described above.
In the zero discharge path, the opening area of the 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. Then, the discharge flow control device 40 applies the high fluid pressure before passing through the orifice 46 to the first fluid pressure via the first fluid pressure supply passage 47A, the switching valve 48, the pump housing 11A, and the communication passage 49 formed in the adapter ring 19. The pressure is guided to the pressure chamber 44A, the reduced pressure after passing through the orifice 46 is guided to the second fluid pressure chamber 44B as described above, and the cam ring 22 is attached to the spring 42 by the pressure difference between the pressures acting on the two fluid pressure chambers 44A and 44B. The pump 10 is moved against the force to change the volume of the pump chamber 23 so that the discharge flow rate of the pump 10 can be controlled.

The switching valve 48 is connected to the front casing 1.
A cap 5 in which a spring 52 and a switching plunger 53 are accommodated in a valve storage hole 51 formed in 1A, and the plunger 53 urged by the spring 52 is screwed to the casing 11A.
4 carried. The switching plunger 53 includes the switching valve element 5.
5A, a valve body 55B, and a pressurizing chamber 56 of the switching valve body 55A.
A through the first fluid pressure supply passage 47A, the second back pressure chamber 56B, in which the other spring 52 of the valve body 55B is stored, through the communication passage 57 formed in the pump housing 11A and the adapter ring 19. The fluid pressure chamber 44B communicates. Further, the intermediate chamber 5 between the switching valve body 55A and the valve body 55B.
6C is formed with the aforementioned suction passage 25A penetrating therethrough.
Suction side fluid is delivered. 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 plunger 53 is set to the original position shown in FIG. 2 by the biasing force of the spring 52, and the switching valve body 55A communicates with the first fluid pressure chamber 44A. Is closed, and the pressurizing chamber 56 is
The switching plunger 53 is moved by the high-pressure fluid added to A 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 a vehicle in which the rotation speed of the pump 10 is low, the pressure is discharged from the pump chamber 23 and the pressure chamber 5 of the switching valve 48 is discharged.
The pressure of the fluid reaching 6A is still low, the switching valve 48 is in the original position, and 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) When the pressure of the fluid discharged from the pump chamber 23 and reaching the pressurizing chamber 56A of the switching valve 48 increases due to the increase in the rotation speed of the pump 10, the switching valve 48 resists the urging force of the spring 52. Then, the switching plunger 53 is moved to open the communication passage 49, and the high-pressure fluid is supplied 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 further 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 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 limit of movement against the stopper 19B 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.

(B) Vane pressurizing device 60 The vane pressurizing device 60 is provided with the groove 16 of the pressure plate 18 and 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 separated by the vane pressurizing device 60. The contact pressure is increased, and the backflow of the pressure fluid can be prevented.

However, in the case of the pump 10, FIG.
As shown in FIG. 2, between the pump housing 11A and the adapter ring 19 (fitting boundary), the pump housing 11A
O-rings 71 and 72 surrounding communication passages 49 and 57 provided so as to extend from the connector ring 19 to the adapter ring 19 are provided. The O-ring 71 is mounted in a groove 73 provided around the communication passage 49 on the outer peripheral surface of the adapter ring 19 (FIG. 3), and the O-ring 72 is connected to the communication passage 57 on the outer peripheral surface of the adapter ring 19.
It is mounted in a groove 74 provided around it (FIG. 3).

In the cover 11B of the pump 10, a lubricating oil supply passage 121 is formed from the suction passage 25B around the bearing 15C of the pump shaft 12, so that the pump housing 1
In 1A, a lubricating oil return passage 122 that returns to the suction passage 25A from around the bearing 15B of the pump shaft 12 is provided.

Therefore, according to the present embodiment, the following operations are provided. The adapter ring 19 is easily fitted into the fitting hole 20 of the pump housing 11A with the elastic deformation of the O-rings 71 and 72 when the fitting is assembled to the pump housing 11A, so that the fitting and assembling property can be improved. .

After the adapter ring 19 is fitted to the pump housing 11A, the adapter ring 19 is mounted on the pump housing 11A.
O-rings 71 and 72 are interposed in a sandwiching state between the pump ring 10 and the vibration of the adapter ring 19 when the pump 10 operates.
Generation of abnormal noise can be reduced.

A simple configuration using only the O-rings 71 and 72 without the need to improve the processing accuracy of the fitting hole 20 of the pump housing 11A and the processing accuracy of the outer peripheral surface of the adapter ring 19 is required. The vibration of the adapter ring 19 and the generation of abnormal noise when the pump 10 operates can be reduced.

The fluid pressure communication passages 49, 57 extending from the side of the pump housing 11A to the adapter ring 19 are surrounded by O-rings 71, 72 between the adapter ring 19 and the pump housing 11A. Fluid pressure leakage can be prevented, and control accuracy can be improved.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, 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. For example, O
The rings 71 and 72 may be mounted in grooves provided around the communication passages 49 and 57 on the inner peripheral surface of the fitting hole 20 of the pump housing 11A.

[0036]

As described above, according to the present invention, in a variable displacement pump, vibration and abnormal noise of the adapter ring during operation of the pump can be improved while improving the fitting of the adapter ring to the pump casing. Occurrence can be reduced.

[Brief description of the drawings]

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

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

FIG. 3 is a schematic view showing an adapter ring.

[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 room 40 Discharge flow control device 41 Spring room 42 Spring 44A First fluid pressure chamber 44B Second fluid pressure Chamber 71, 72 O-ring

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuhiko Koyama 112-1 Hagadai, Haga-cho, Haga-gun, Tochigi F-term in Showa Tochigi Development Center Co., Ltd. 3H044 AA02 BB05 BB08 CC01 CC11 CC14 CC27 DD09 DD11 DD24 DD28 DD35

Claims (1)

[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. An adapter ring to be mounted; a cam ring fitted to the adapter ring to form a pump chamber between the outer periphery of the rotor; and a cam ring capable of moving and displacing within the adapter ring, and maximizing the volume of the pump chamber. Such a biasing force is applied to the cam ring, and the first and second fluid pressure chambers are divided between the cam ring and the adapter ring, and the cam ring is biased by the differential pressure between the pressures acting on the two fluid pressure chambers. And a discharge flow rate control device capable of controlling the discharge flow rate by changing the volume of the pump chamber. Comprising a communication passage of the fluid pressure, from the side of the single in the first or second fluid pressure chamber through the adapter ring,
A variable displacement pump characterized in that an O-ring surrounding the communication path is interposed between an adapter ring and a pump casing.