JP2001065467A - Variable displacement vane pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase workability for assembly of a side plate in a variable displacement vane pump. SOLUTION: This vane pump comprises disk-shaped side plates and covers sandwiching a rotor, vanes, and a cam ring so as to form a pump chamber, a circular ring-shaped adopter ring sandwiched between the side plates and covers and storing the cam ring, and a housing 1 storing the side plates and adopter ring between the covers and the housing 1. In this case, a recessed storing part 1a storing the side plates and adopter ring in a stacked state is formed in the housing 1, the inner diameter of a bottom side wall part 7 allowing the outer peripheral surface of the inner wall of the recessed storing part 1a of the side plate to be fitted thereto is formed smaller than the inner diameter of a front side wall part 72 allowing the outer peripheral surface of the adopter ring to be fitted thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a conventional variable displacement vane pump,
There is a type in which a cam ring surrounding each vane protruding from the outer periphery of a rotating rotor is provided, and the cam ring is moved within an adapter ring to change a pump discharge flow rate.

A variable displacement vane pump of this type includes an adapter ring, a cam ring, and a side plate that abuts a side surface of a rotor to define a pump chamber. The side plate is formed in a disk shape, and the adapter ring is connected to the side plate. While the disk is formed in the shape of a disk having the same diameter as the above, a cylindrical inner wall is formed in a housing for accommodating them, and a side plate and an adapter ring are stacked and accommodated in the housing.

[0004]

However, in such a conventional variable displacement vane pump, when the disk-shaped side plate is inserted into the inside of the housing,
Even if the side plate is slightly tilted, galling or the like is generated between the inner plate and the inner wall of the housing and stops, so that it is difficult to fit the side plate into a predetermined position in the housing, resulting in poor workability.

The present invention has been made in view of the above problems, and has as its object to improve the workability of assembling a side plate in a variable displacement vane pump.

[0006]

According to a first aspect of the present invention, a plurality of vanes projecting from the outer periphery of a rotating rotor, a cam ring surrounding each vane, and a pump chamber are defined with the rotor, each vane and the cam ring interposed therebetween. A disk-shaped side plate and a cover, and an annular adapter ring that is interposed between the side plate and the cover and accommodates the cam ring;
The present invention is applied to a variable displacement vane pump having a housing for accommodating a side plate and an adapter ring between the cover and a cover.

A housing recess for accommodating the side plate and the adapter ring is formed in the housing, and the inner diameter of the inner side wall of the inner wall of the housing recess into which the outer peripheral surface of the side plate is fitted is determined by the outer peripheral surface of the adapter ring. Are formed smaller than the inner diameter of the front side wall portion to be fitted.

[0008]

According to the first aspect of the present invention, since the inner diameter of the rear side wall is smaller than the inner diameter of the front side wall, the gap between the side plate and the front side wall is larger than the gap between the side plate and the rear side wall. When inserting the side plate along the front side wall, even if the side plate is slightly inclined, there is no galling etc. between the side plate and the front side wall, and the side plate smoothly goes to the position where it fits into the back side wall It can be inserted and workability can be improved.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show a variable displacement vane pump to which the present invention can be applied. This itself has already been proposed by the present applicant as Japanese Patent Application No. 10-337132.

As shown in FIG. 2, the housing 1 is formed with a columnar housing recess 1 a, and the opening end of the housing recess 1 a is closed by a cover 7. A disc-shaped side plate 2 and an annular adapter ring 3 are stacked and housed inside the housing recess 1a from the bottom (the innermost side) side, and a cam ring 5 is housed inside the adapter ring 3. The rotor 6 is housed inside the cam ring 5. The side surfaces of the adapter ring 3, the cam ring 5, and the rotor 6 abut against the cover 7 and are sealed.

A through hole 1b is formed in the bottom surface of the housing recess 1a, and a drive shaft 8 is rotatably supported in the through hole 1b via a metal bearing 9. The distal end side of the drive shaft 8 penetrates through the side plate 2 and the rotor 6 to reach a support hole 7a formed in the cover 7, and is rotatably supported by the support hole 7a via a metal bearing 10. The rotor 6
The drive shaft 8 is spline-coupled in the middle of the drive shaft 8 and rotates integrally with the drive shaft 8. The drive shaft 8 is driven to rotate by an engine (not shown) via a pulley and a belt.

As shown in FIG. 1, a plurality of notches are formed radially in the rotor 6, and a vane 11 is housed in each notch so as to be able to protrude and retract in the radial direction of the rotor 6. When the rotor 6 rotates, the vane 11 extends from the notch.
Of the cam ring 5 slidably contacts the inner peripheral surface of the cam ring 5.
Each of the pump chambers 12 defined between them expands and contracts.

The side plate 2 is formed with a kidney type high-pressure groove 13A and a low-pressure groove 14A. High pressure groove 1
3A and the low-pressure groove 14A are formed at symmetrical positions with respect to the drive shaft 8, and face the pump chamber 12 on the discharge side and the suction side, respectively. The cover 7 has a rotor 6
A high-pressure groove 13B and a low-pressure groove 14B of a kidney type are formed at positions opposite to the high-pressure groove 13A and the low-pressure groove 14A on the side of the side plate 2, with the pump chamber 12 on the discharge side and the suction side, respectively. I'm coming.

The high-pressure groove 13A communicates with a high-pressure chamber 16 formed at the bottom (the innermost part) of the housing recess 1a through a high-pressure passage 15 penetrating the side plate 2. This high pressure chamber 1
6 communicates with the discharge port 18 via a variable orifice 25 as described later. The low-pressure groove 14B communicates with the suction port 19 (and the tank T) via a low-pressure passage 17 formed in the cover 7.

The cam ring 5 is swingably supported on the left and right sides of the drive shaft 8 with the pin 4 as a pivot point. As shown in FIG. 1, in a state where the cam ring 5 is eccentric with respect to the drive shaft 8,
When the rotor 6 rotates in the counterclockwise rotation direction, the operating oil from the suction port 19 is sucked into the pump chamber 12 on the suction side (the low-pressure grooves 14A and 14B side) that expands, while the discharge side (the high-pressure groove) contracts. 13A, 13B side) pump room 12
The hydraulic oil is discharged from the discharge port 18 toward the discharge port 18.

On the side of the housing 1, there is formed a plug hole 1c which opens into the housing recess 1a (specifically, opens into a second cam pressure chamber 31 which will be described later), and the plug 20 is screwed into the plug hole 1c. Attached. A cylinder hole 20a is opened at the tip end of the plug 20, and a control plunger 21 is slidably housed in the cylinder hole 20a. The distal end of the control plunger 21 contacts the side surface of the cam ring 5 via a feedback pin 61 that penetrates a through hole 3a formed in the adapter ring 3.

The control plunger 21 is formed with a plunger hollow portion 21a opening at the base end thereof, and a spring 22 is housed inside the plunger hollow portion 21a. The spring 22 is interposed between the bottom surface of the cylinder hole 20a and the bottom surface of the plunger hollow portion 21a.
1 and the cam ring 5 via the feedback pin 61
To its maximum discharge position.

A recess 20b is formed on the outer periphery of the plug 20, and an annular fluid chamber 23 is provided between the recess 20b and the plug hole 1c.
Is defined. An O-ring 2 is provided at the opening end of the plug hole 1c.
4 is provided to seal the fluid chamber 23. A variable orifice 25 penetrating through the plug 20 and communicating the fluid chamber 23 with the cylinder hole 20a is formed. Hydraulic oil from the high-pressure chamber 16 is introduced into the fluid chamber 23 through a fluid passage 36 formed in the housing 1, and is further introduced into the variable orifice 25.
Through the cylinder hole 20a and the plunger hollow portion 21
a.

The opening area of the variable orifice 25 is adjusted by the proximal edge 21b of the control plunger 21 which slides in the cylinder bore 20a. As the eccentric amount of the cam ring 5 becomes smaller, the control plunger 21 is displaced rightward in FIG. 1 and the opening area of the variable orifice 25 is reduced.

A plurality of through holes 26 are formed in the cylindrical portion of the control plunger 21. The plunger hollow portion 21a is always in communication with the fluid chamber 27 formed between the housing recess 1a of the housing 1 and the adapter ring 3 through each through hole 26. The fluid chamber 27 communicates with the discharge port 18 through the through hole 28. As a result, the plunger hollow portion 21a is
6. Discharge port 18 through fluid chamber 27 and through hole 28
He is always in communication with

In order to swing the cam ring 5 against the spring 22, the first cam pressure chamber 32 and the second cam pressure chamber 3 are located inside the adapter ring 3 so as to sandwich the cam ring 5.
1 is defined. A seal member 30 slidably contacting the outer periphery of the cam ring 5 is interposed on the adapter ring 3.
Thereby, the space between the first cam pressure chamber 32 and the second cam pressure chamber 31 is sealed. As the pressure in the first cam pressure chamber 32 increases with respect to the second cam pressure chamber 31, the cam ring 5 swings against the spring 22, and the pump discharge flow rate gradually decreases.

The first cam pressure chamber 32 selectively communicates with the suction port 19 and the high pressure chamber 16 via the switching valve 40. The switching valve 40 includes a cylinder 42 formed in the housing 1 and a spool 41 housed in the cylinder 42.

The spool 41 has a land 41a and a land 41b. The second spool pressure chamber 45 defined on the right side of the land portion 41a in FIG.
8, communicates with the discharge port 18 through the through hole 49. Drain fluid chamber 46 defined between land portions 41a and 41b
And the suction port 19 through the drain port 50. The first spool pressure chamber 47 defined on the left side of the land portion 41b communicates with the high-pressure chamber 16 through the through holes 56 and 58.

The open end of the cylinder 42 is closed by a plug 43. A return spring 44 is interposed between the base end of the spool 41 and the bottom of the cylinder 42. The first cam pressure chamber 32 communicates with the suction port 19 at a closed position where the spool 41 comes into contact with the plug 43 by the biasing force of the spring 44.

When the differential pressure across the variable orifice 25 guided to both ends of the spool 41 rises above a predetermined value, the spool 41 moves to the open position on the right side in FIG. A chamber 32 communicates with the high pressure chamber 16.

The second cam pressure chamber 31 is provided in the side plate 2
Is always in communication with the high-pressure chamber 16 via a fixed orifice 62 formed at the bottom. First cam pressure chamber 32 and second cam pressure chamber 3
As the differential pressure across the variable orifice 25 led to 1 increases, the cam ring 5 swings against the spring 44 and the pump discharge flow rate decreases.

The second cam pressure chamber 31 communicates with the annular port 64 of the switching valve 40 through the through hole 63, and the annular port 64
Is the drain fluid chamber 4 by the land 41a of the spool 41.
6 is selectively communicated. A plurality of notches 65 are cut at the end of the land portion 41a on the side of the drain fluid chamber 46, and when the spool 41 moves to the right in FIG. 1 as the pump discharge flow rate increases, the second cam pressure chamber 31 and the drain The opening area communicating with the fluid chamber 46 gradually increases.

Next, the operation of the variable displacement vane pump will be described.

In the stopped state of the pump, as shown in FIG. 1, the cam ring 5 is biased by the spring 22 and is at the maximum eccentric position. When the rotor 6 is rotated from this state, hydraulic oil is discharged from the pump chamber 12 to the high-pressure chamber 16. The hydraulic oil in the high-pressure chamber 16 is decompressed through the variable orifice 25 and supplied from the discharge port 18 to a hydraulic actuator of the power steering device through a pipe (not shown). The oil pressure in the high-pressure chamber 16 is introduced into the first spool pressure chamber 47 via the throttle 59. While the pump rotation speed is low, the spool 41 of the switching valve 40 is held in the closed position by the urging force of the spring 44, the tank pressure is guided to the first cam pressure chamber 32, and the pump discharge pressure is supplied to the second cam pressure chamber 31. Is guided, and the cam ring 5 is held at the maximum eccentric position. As a result, the pump discharge amount increases in proportion to the pump rotation speed, and the pump discharge pressure increases sufficiently during low-speed running of the vehicle, so that the hydraulic assist force required for the power steering device can be secured.

When the discharge pressure of the high-pressure chamber 16 increases as the pump rotation speed increases, the spool 41 of the switching valve 40 is displaced rightward in FIG.
The pump discharge pressure is led to the first cam pressure chamber 32 and the tank pressure is led to the second cam pressure chamber 31. The reaction force F1 based on the upstream pressure of the variable orifice 25 guided to the first cam pressure chamber 32 is changed to a pressure F2 guided to the second cam pressure chamber 31.
The cam ring 5 swings until it balances with the sum (F2 + Fs) of the spring force Fs and the spring force Fs of the spring 22. When the amount of eccentricity of the cam ring 5 decreases in this manner, the amount of change in the volume of the pump chamber 12 due to the rotation of the pump decreases, and the amount of pump discharge from the discharge port 18 is kept constant as the pump rotational speed increases.

When the pump rotation speed further increases and the amount of eccentricity of the cam ring 5 decreases, the control plunger 21 following the cam ring 5 gradually reduces the opening area of the variable orifice 25, and the differential pressure across the variable orifice 25 increases. The amount of eccentricity of the cam ring 5 is further reduced. The effect of the reduction in the opening area of the variable orifice 25 and the reduction in the amount of eccentricity of the cam ring 5 combine to obtain a drooping characteristic in which the pump discharge flow rate decreases as the pump rotation speed increases. . Thus, during high-speed running of a vehicle in which the pump rotation speed (engine rotation speed) is high, the pump discharge flow rate is reduced, and the hydraulic assist force of the power steering device does not need to be excessive. And the rise in hydraulic oil temperature can be suppressed.

By the way, as described above, the housing 1 is formed with the cylindrical accommodation recess 1a, and the disc-shaped side plate 2 and the annular adapter ring 3 are stacked and accommodated in the accommodation recess 1a. When the disk-shaped side plate 2 is inserted into the inner part of the housing 1, even if the side plate 2 is slightly inclined, the side plate 2 stops due to the occurrence of galling between the inner wall surface of the housing recess 1a.
In the housing 1 is difficult to fit in a predetermined position, and workability is poor.

To cope with this, according to the present invention, as shown in FIG. 3, a rear side wall portion 71 for fitting the outer peripheral surface of the side plate 2 to the housing 1, and a near side wall for fitting the outer peripheral surface of the adapter ring 3 to the housing 1. Parts 72 are formed respectively,
Is formed smaller than the inner diameter d2 of the front side wall portion 72. If d1 and d2 are actually set to about 60 mm, the difference d2-d1 between them is set to about 0.1 mm.

In response to this, the outer diameter D1 of the side plate 2 is formed smaller than the outer diameter D2 of the adapter ring 3,
The hammer eye (dimension difference) of the side plate 2 with respect to the rear side wall portion 71 and the hammer eye of the adapter ring 3 with respect to the front side wall portion 72 are set to be equal.

As shown in FIG. 4, a step 73 located between the rear side wall 71 and the front side wall 72 is tapered. The step 73 is formed at a position facing the outer peripheral surface of the side plate 2 so as not to interfere with the adapter ring 3.

The operation of the embodiment of the present invention configured as described above will now be described.

The inner diameter d1 of the rear side wall 71 is changed to the near side wall 72.
Is smaller than the inner diameter d2, the gap between the side plate 2 and the front side wall portion 72 is larger than the gap between the side wall portion 71 and the disc-shaped side plate 2 can be easily inserted into the inside of the housing 1. Can be. When the side plate 2 is inserted along the front side wall portion 72, even if the side plate 2 is slightly tilted, the side plate 2 is fitted to the rear side wall portion 71 without causing galling or the like with the front side wall portion 72. It can be inserted smoothly to the position where it fits, and workability can be improved.

Since the adapter ring 3 is thicker than the side plate 2 and is inserted into the housing 1 at a short distance, the adapter ring 3 can be inserted smoothly even if the gap to the front side wall 72 is small.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a variable displacement vane pump according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the same variable displacement vane pump.

FIG. 3 is a sectional view of the housing.

FIG. 4 is an enlarged sectional view of part A of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 1a Housing recess 2 Side plate 3 Adapter ring 5 Cam ring 6 Rotor 7 Cover 11 Vane 12 Pump room 71 Back side wall part 72 Front side wall part 73 Step

Continued on the front page F term (reference) 3H040 AA03 BB01 BB11 CC16 CC22 DD01 DD06 DD40 3H044 AA02 BB05 CC14 CC22 DD01 DD04 DD28 DD43

Claims (1)

[Claims] A plurality of vanes protruding from an outer periphery of a rotating rotor; a cam ring surrounding each vane; a disk-shaped side plate and a cover defining a pump chamber with the rotor, each vane and the cam ring interposed therebetween; An annular adapter ring that accommodates the cam ring between the plate and the cover, and a housing that accommodates the side plate and the adapter ring between the cover and the cover. In the variable displacement vane pump, a housing recess is formed in the housing to house the side plate and the adapter ring in a stacked manner, and an inner diameter of an inner side wall portion of the inner wall of the housing recess to which an outer peripheral surface of the side plate is fitted. Is smaller than the inside diameter of the front side wall to which the outer peripheral surface of the adapter ring is fitted. A variable displacement vane pump characterized by having been realized.