JP2977964B2 - Vane pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In general, a vane pump has a cam ring having a substantially elliptical cam surface on an inner periphery, a rotor rotating in the cam ring, and reciprocating slits formed at equal intervals in a circumferential direction on the outer periphery of the rotor. A large number of vanes inserted as much as possible, and the cam ring and the rotor are clamped from both sides.
Plate (or plate-shaped body), and each vane slides on the cam ring with the rotation of the rotor to increase or decrease the volume of a pump chamber formed between two adjacent vanes. And suction and discharge of oil.

In such a vane pump, the oil discharged from the pump is introduced into the inner peripheral side of each slit in order to push each vane from the slit of the rotor and surely contact the inner surface of the cam ring. I have.
And conventionally, on the surface which contacts the rotor of both plates,
Four arc-shaped grooves located on the same circumference are formed, and the discharge oil is directly introduced into two of the grooves, and two grooves between them are formed through a narrow throttle passage communicating with the grooves. Discharge oil is introduced.

In the vane pump, the vane slightly jumped out by centrifugal force at the time of starting is hit in reverse by the cam when it enters the discharge stroke, and pushes out the oil inside the slit into which the vane is inserted. The extruded oil passes through the throttle passage and is sent out to an arc-shaped groove on the suction side of the pump. At this time, the pressure of the oil on the inner circumferential side of the slit increases due to the resistance flowing out of the throttle passage, and the adjacent vane that has not yet sufficiently protruded is pushed out. By repeating this, finally all the vanes completely fly out and come into contact with the cam ring to start discharging.

[0005]

In the above-mentioned conventional vane pump, if the passage connecting the arc-shaped grooves formed in both plates is not sufficiently small, the hydraulic pressure inside the vane does not increase at low rotation, and the startability is low. If the passage becomes worse and the passage is made narrower, the outflow resistance becomes larger at the time of high rotation, causing a problem that an increase in power loss and an increase in oil temperature are caused.

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned disadvantages, and it is an object of the present invention to provide a vane pump having good startability and having a small power loss even at a high rotation speed.

[0007]

SUMMARY OF THE INVENTION A vane pump according to the present invention comprises a cam ring having a cam formed on an inner surface thereof, a rotor rotating in the cam ring, and slits formed on the outer periphery of the rotor at equal circumferential intervals. And a plate that sandwiches the cam ring and the rotor from both sides. A plurality of circular arcs communicating with the inner peripheral end of each slit are provided on the rotor-side surface of the plate. A groove is formed, and the vane is pushed out by introducing discharge oil into these arc-shaped grooves, and further on one end surface of the rotor, on the outer peripheral side from the bottom of each slit.
An annular groove is formed by shifting, and when each vane retreats to the inner peripheral side of the rotor, the opening area is reduced by these vanes.
Ri, is opened when the vane is moved to the outer peripheral side of the rotor
And the side facing the other end face of the rotor.
The plate has a throttle passage connecting the arc-shaped grooves .

[0008]

In the vane pump according to the present invention, an arc-shaped groove for introducing hydraulic pressure for pushing the vane is communicated by an annular groove formed in the rotor during normal operation, and the annular groove is substantially shut off at the time of starting. Thus, the hydraulic pressure in the arc-shaped groove is easily increased, and the startability is improved.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a longitudinal sectional view of a vane pump according to one embodiment of the present invention, and FIG. 2 is a sectional view taken along a line II-II of the vane pump, which projects a substantially cylindrical front body 2 and a plate-shaped rear body 4. The pump cartridge 8 is accommodated in the pump body 6 formed together.

An input shaft 10 is inserted into the pump body 6 from the small-diameter cylindrical portion 2a of the front body 2, and the bearing 1
It is rotatably supported by 2 and 14. Reference numeral 16 denotes an oil seal for maintaining the liquid tightness in the pump body 6.
Near the tip 10a of the input shaft 10 inside the pump body 6,
The rotor 18 is connected by a spline and driven to rotate. Radial slits 19 are formed in the rotor 18 at equal intervals in the circumferential direction.
A vane 20 is inserted into the housing 9 so as to be able to protrude and retract. As shown in FIGS. 2 and 3, each of the slits 19 has an end portion (bottom portion) closer to the inner circumference, which is larger than the thickness of the vane 20. A cam ring 22 having a substantially elliptical inner cam surface is provided on the outer peripheral side of the rotor 18.

The rotor 18 and the cam ring 22
Are sandwiched by a pressure plate 24 and a rear body 4 arranged in the front body 2, and the rear body 4, the cam ring 22 and the pressure plate 2
4 is positioned in the rotational direction by a pin 26.

The front body 2 and the rear body 4 are provided with a suction port 2b and suction passages 2c, 4a. The pump chambers formed by the two adjacent vanes 20 pass through the passages 2c, 4a. The sucked oil passes through a discharge passage 24 a provided in the pressure plate 24, and is discharged from a discharge chamber 2 d at the bottom of the front body 2.
It is discharged into.

On the surface of the pressure plate 24 on the rotor 18 side, arc-shaped grooves 24b and 24d divided into four parts are formed at positions facing the inner peripheral ends of the slits 19 formed in the rotor 18. And are connected by a throttle passage 24c. On the other hand, an arc-shaped groove 4b is also formed on the surface of the rear body 4 on the rotor 18 side at a position corresponding to the arc-shaped grooves 24b and 24d. The arc-shaped groove 4b is not provided with a throttle passage to be connected. Of the four arc-shaped grooves 24b and 24d of the pressure plate 24, two arc-shaped grooves 24d located in the suction region penetrate and communicate with the protruding chamber 2d. Also, the rotor 18
An annular groove 18a is formed on the surface on the side of the rear body 4 at a position facing the portion near the outer periphery of the arc-shaped groove 4b.

As shown in FIG. 3, the annular groove 18a traverses a portion near the inner periphery of each slit 19 into which the vane 20 is inserted. To elaborate,
Half the width of the annular groove 18 a is provided so as to cross the enlarged portion at the bottom of the slit 19, and the other half crosses the portion where the width of the slit 19 is substantially equal to the thickness of the vane 20. Therefore, when the vane 20 retreats to the inner peripheral side and enters the enlarged portion of the slit 19, the portion formed as the annular groove 18a is completely shut off (see FIG. 5).
It is designed to communicate slightly with the enlarged section of 9,
On the other hand, when the vane 20 is protruding to the outer peripheral side,
The annular groove 18a communicates completely, and the divided arc-shaped groove 4b of the rear body 4 is connected via the annular groove 18a.

In the vane pump having the above-described structure, before the start of the operation, the vane 20 retreats to the inside of the slit 19 to substantially cut off the annular groove 18a.
Begins to rotate, the vane 20 slightly pops out due to centrifugal force (see FIGS. 4 and 5), and when it reaches a position near the position where the discharge stroke is completed (the vane at the left end in FIG. 4), the cam ring 2
2 and is pushed in reverse. When the vane 20 is pushed in, the oil on the bottom side of the slit 19 into which the vane is inserted is pushed out and flows into the arc-shaped grooves 4b and 24b. Arc-shaped grooves 4b and 2
The throttle passage 24c connecting the upper and lower bodies 4b and 24d is provided only in the pressure plate 24.
Most of the annular groove 18a connecting the side arc-shaped grooves 4b is also cut off and narrowed, so that the pressure in the arc-shaped grooves 4b and 24b rises and pushes the vane 20 in the adjacent slit 19 to push the cam ring 22 to the cam ring 22. Abut.

When the vane 20 is pushed in in this manner, the pressure in the arc-shaped grooves 4b and 24b increases quickly, so that the startability of the vane pump can be improved. During normal operation of the vane pump, the vane pump flows from the arc-shaped grooves 4b and 24b in the discharge area to the other arc-shaped grooves 4b and 24d through the annular groove 18a having a larger sectional area than the conventional throttle passage. The oil resistance is reduced, the power loss is reduced, and the horsepower consumption is significantly reduced. Further, it is also possible to prevent the deterioration of the oil by suppressing the rise in the oil temperature.

[0017]

As described above, according to the present invention, the startability of the vane pump can be improved, the power loss at the time of high-speed rotation can be reduced, the oil temperature rise can be suppressed, and the deterioration of the oil can be reduced. Can be prevented. In addition, since the vane pump starts discharging oil at a very low speed, the range of the number of rotations can be widened.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a vane pump according to one embodiment of the present invention.

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

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 shows a different operating state of FIG. 5;

[Explanation of symbols]

 4 Plate (rear body) 4b Arc-shaped groove 18 Rotor 18a Annular groove 19 Slit 20 Vane 22 Cam ring 24 Plate (pressure plate) 24b, 24d Arc-shaped groove

Claims (1)

(57) [Claims] 1. A cam ring having a cam formed on an inner surface thereof, a rotor rotating within the cam ring, and a vane movably inserted into slits formed at equal intervals in a circumferential direction on the outer periphery of the rotor. A plate that sandwiches the cam ring and the rotor from both sides, a plurality of arc-shaped grooves communicating with the inner peripheral end of each slit are formed on the rotor-side surface of the plate, and the arc-shaped grooves are formed in these arc-shaped grooves. In the vane pump in which the discharge oil is introduced to push out the vane, one end face of the rotor is provided at the bottom of each slit.
Shifted to the outer peripheral side to form an annular groove, each vane stop the opening area by these vanes when retracted to the inner peripheral side of the rotor, the vanes are configured to open when moved to the outer peripheral side of the rotor And the other end face of the rotor.
To connect the arc-shaped groove to the opposite plate,
A vane pump provided with a passage .