JPS626304Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a variable displacement vane pump, and more particularly, a movable ring for accommodating a rotor having a large number of vanes is attached to the pump housing via an axial pivot pin provided in the pump housing. The movable ring is rocked by a pushing member housed in the inner hole so as to be movable in the radial direction, and attached to a portion of the pump housing on the opposite side of the pivot portion of the movable ring so as to be movable in the radial direction. The present invention relates to a variable displacement vane pump in which the amount of eccentricity of the movable ring relative to the rotor is changed by moving the movable ring.

Generally, in this type of variable displacement vane pump, the suction port and the discharge port are located opposite to each other on both sides of the movable ring, so the pump housing must be placed so that the pivot pin and the pushing member do not interfere with each port. It must be installed at a considerable distance from the center of the pump. For this reason, the diameters of the pivot pin, the outer periphery of the movable ring that is pivotally attached to or engaged with the pushing member, and the inner hole of the pump housing must be increased, or both must be made into a special shape. Therefore, there are disadvantages in that the pump itself becomes unnecessary and its manufacture becomes complicated. Additionally, there is generally a slight clearance between the movable ring and the pivot pin due to manufacturing reasons, and in the early stages of pump startup when there is not enough fluid pressure to press the movable ring against the pivot pin. , the movable ring may vibrate due to the influence of the above-mentioned clearance, and stable pump operation may not be expected.

For example, in the pump shown in US Pat. Since there is a clearance between the movable ring and the pivot pin, vibration of the movable ring is unavoidable at the beginning of pump startup.

The present invention was developed in view of the above-mentioned circumstances, and its purpose is to avoid increasing the size of the movable ring by taking into account the pivoting of the movable ring to the pivot pin and the engagement with the pushing member. Simple structure,
To provide a variable displacement vane pump that is easy to manufacture and can prevent vibration of a movable ring.

Hereinafter, the present invention will be explained based on the drawings. FIGS. 1 and 2 show an example of a variable displacement vane pump according to the present invention. A pump housing 10 of this variable displacement vane pump (hereinafter sometimes referred to as vane pump) is composed of a front housing 11, a guide housing 12, and a rear housing 13, and a pressure plate 14 is fitted inside the rear housing 13. It is inserted. This pressure plate 14 rests elastically on the guide housing 12 and, together with the front housing 11, accommodates a rotor 23 with a movable ring 21 and a number of vanes 22 in the inner bore 12a of the guide housing 12. It forms a columnar storage chamber, and together with the rear housing 13 forms a pressure chamber _R1 .

The movable ring 21 has a perfect circular shape and has a predetermined smaller diameter than the inner hole 12a of the guide housing 12, and is accommodated in the inner hole 12a of the guide housing 12 via a pivot pin 25, which will be described later, so as to be able to swing in the radial direction. The flow control valve 30 is
It is connected to the spool 31 of. This movable ring 21 forms a fluid chamber R ₂ between its outer periphery and the peripheral wall of the inner hole 12 a of the guide housing 12 . Further, the rotor 23 is connected to the front housing 11
The movable ring 2 is spline-fitted to one end of a rotating shaft 24 that is liquid-tightly and rotatably supported by the movable ring 2.
A pump chamber P is formed between the movable ring 21 and the inner periphery of the movable ring 21 .

On the other hand, on the inner surface of the front housing 11,
A suction port 11a and a discharge port 11b are formed. The suction port 11a communicates with a suction passage 11c provided in the front housing 11 and the suction region of the pump chamber P, and the discharge port 11b communicates with the discharge region of the pump chamber P and the pressure chamber _R1 . Also,
The front housing 11 is formed with a suction passage 11c and a conduction passage 11d that communicates with the fluid chamber _R2 , and the rear housing 13 is formed with a discharge passage 13a that communicates with the pressure chamber _R1 . An orifice forming member 15 is fitted into the discharge passage 13a, and the pressure chamber _R1 and the discharge passage 13a communicate with each other through the fixed orifice 15a.

A pivot pin 25 is fixed to the upper portions of the front housing 11 and the pressure plate 14 in the drawing. The pivot pin 25 extends in the pump axial direction and passes through the inner hole 12a of the guide housing 12 with a slight gap from the top of the inner hole 12a in the drawing. The guide housing 12 also has a pair of plugs 32a and 32b at both ends.
A through hole 12b is formed in a tangential direction to the bottom of the inner hole 12a in a liquid-tight manner, and a flow control valve 30 is assembled in this through hole 12b. The flow control valve 30 includes a spool 31 provided with a relief valve mechanism 30a, and a spool 31 interposed between the spool 31 and a plug 32a.
The spring 33 urges the spring to the left in the second figure. The spool 31 has an axial inner hole on the right side in the figure, and a relief valve mechanism 30a is assembled into the inner hole. The relief valve mechanism 30a includes a cylindrical valve seat member 34 screwed onto the open end of the inner hole, a ball-shaped valve body 35, and a pusher 3.
6, and a spring 37 that urges the valve body 35 toward the valve seat side of the valve seat member 34.
As a result, the through hole 12 of the guide housing 12
Inside b, there is a high pressure chamber _R3 communicating with the pressure chamber _R1 , an intermediate chamber _R4 communicating with the fluid chamber _R2 , and a discharge passage 13a.
A low pressure chamber _R5 is formed which communicates with the chamber. This low pressure chamber _R5 communicates with the intermediate chamber _R4 and the fluid chamber _R2 via the relief valve mechanism 30a, and when the fluid pressure in the discharge passage 13a reaches a predetermined pressure or higher, the relief valve mechanism 30a is activated. A part of the fluid in the low pressure chamber _R5 and the discharge passage 13a is thereby returned to the fluid chamber _R2 , and the fluid pressure in the discharge passage 13a is maintained at a predetermined pressure or less. Furthermore, an engagement pin 26 extending in the pump axial direction is attached to the outer periphery of the spool 31 at a portion where the fluid chamber R ₂ and the through hole 12b communicate with each other. A part of the outer periphery of this engagement pin 26 protrudes slightly from the outer periphery of the spool 31 and
Facing the bottom of _R2 . Note that the spool 31 is in contact with the plug 32b due to the biasing force of the spring 33, and slides to the right in the second diagram according to the differential pressure between the fluid pressure in the high pressure chamber _R3 and the fluid pressure in the low pressure chamber _R5 . move.

On the other hand, on the outer periphery of the movable ring 21, a pair of engagement slits 21 are formed at mutually opposite parts on the diametrical line.
a, 21b are formed. Both of these engagement slits 21a and 21b extend in the pump axial direction, and the engagement slit 21a has a size that can be engaged with the pivot pin 25, and the engagement slit 21b can engage with the engagement pin 26. It is formed to a large size. The movable ring 21 engages the pivot pin 25 with its engagement slit 21a.
It is housed in the inner hole 12a of the guide housing 12 so as to be able to swing in the second left-right direction in the drawings with the engagement slit 21b as a fulcrum.
It is directly connected to the spool 31 by engaging with the spool 31. As a result, the movement of the spool 31 is transmitted to the movable ring 21 via the engagement pin 26, and the movable ring 21 moves from an eccentric state to a position where its centers substantially coincide with the rotor 23. This movable ring 21 is urged toward the engagement pin 26 by a pressing mechanism 40 assembled into a stepped hole 12c provided in the upper part of the guide housing 12 in the drawing. The pressing mechanism 40 includes a presser 41 fitted into the inner opening of the stepped hole 12c, and a presser 41 inserted into the inner opening of the stepped hole 12c.
An adjustment screw 42 is screwed into the outer opening of the
and a spring 43 that is interposed between the pusher 41 and the adjustment screw 42 and biases the pusher 41 toward the movable ring 21. Presser 41
A recess extending in the axial direction of the pump is formed in the inner surface of the pump, and both legs of the recess resiliently abut against both sides of the engagement slit 21a on the outer periphery of the movable ring 21 to engage the movable ring 21. It is pressed against the pin 26.

In the vane pump configured in this way,
When not driven, the spool 31 is located on the left side as shown in FIG. 2, and the movable ring 21 is eccentric by the maximum amount. When the engine is driven in this state, the rotating shaft 24 and the rotor 23 integrated therewith rotate.
The fluid is sucked into the pump chamber P through the suction passage 11c and the suction port 11a, is discharged as pressure fluid into the pressure chamber _R1 through the discharge port 11b, and is further supplied to appropriate fluid pressure operated equipment through the fixed orifice 15a and the discharge passage 13a. be done. During this time, a part of the pressure fluid in the pressure chamber _R1 flows into the high pressure chamber _R3 to fill it, and a part of the supply fluid in the discharge passage 13a also flows into the low pressure chamber _R5 . Fulfill this. Therefore, when the rotational speed of the rotating shaft 24 and the rotor 23 (pump rotational speed) increases due to the drive of the engine, and the amount of pressure fluid discharged into the pressure chamber _R1 increases, the high pressure chamber _R3 and the low pressure chamber _R5 When the fluid pressure difference within becomes equal to or higher than the set pressure difference, the spool 31 gradually slides to the right in the second figure against the spring 33. For this reason, the spool 31
The movable ring 21 connected to the rotor 23 swings to the right in FIG. As a result, the discharge amount per rotation of the pump decreases as the pump rotation speed increases, and the fluid supplied to the fluid pressure operated device is controlled to a constant amount regardless of the increase in the pump rotation speed.

By the way, in the vane pump as well, since sufficient discharge pressure is not generated in the discharge region of the pump chamber P at the initial stage of pump startup, the movable ring 21
is not pressed against the pivot pin 25, but at the initial stage of starting the pump, the pusher 4 of the pushing mechanism 40
1, the movable ring 21 is pressed against the engagement pin 26, and when sufficient discharge pressure is generated, the movable ring 21 is pressed against the pivot pin 25 due to the action of this discharge pressure, so that the movable ring 21 and each pin 25,
26, the movable ring 21 does not vibrate, and stable pump operation can be expected.

In this vane pump, in particular, the pusher 41
is provided on the pivot pin 25 side and the movable ring 21 is pressed against the engagement pin 26 from the pivot pin 25 side, so there is no friction between the pivot pin 25 and the pusher 41, and the sliding movement of the movable ring 21 is prevented. is done smoothly. In addition, since the pressing force (resilient force) of the presser 41 against the movable ring 21 can be adjusted by operating the adjustment screw 42, the pressing force between the movable ring 21 and the engagement pin 26 can be appropriately adjusted to ensure a reliable It is possible to prevent looseness, suppress excessive force acting on the spool 31, and prevent an increase in sliding resistance thereof.

In addition, in this vane pump, a pair of engagement slits 21a, 21b are formed on opposite sides of the outer periphery of the movable ring 21, and each of these engagement slits 21a, 21b is connected to a pivot pin 25, an engagement pin 26, it is possible to use a circular ring with a small outer diameter as the movable ring 21, and the inner hole 1 of the guide housing 12 can be used as the movable ring 21.
2a can also be formed into a small circular shape. Therefore, it is not necessary to make the inner hole of the guide housing and the movable ring, and thus the vane pump, into a special shape, which makes manufacturing easy, and the vane pump does not become unnecessarily large. In this vane pump, in particular, since the movable ring 21 and the spool 31 are directly connected via the engagement pin 26,
There is no need to provide any special connecting means for connecting these two parts 21 and 31, and the structure of the connecting part is simple.

In this embodiment, an example is shown in which the spool 31 equipped with a relief valve mechanism is used as the pushing member, but any known appropriate pushing member such as a simple spool without a relief valve mechanism may be used. Moreover, as for the pressing member, in place of each component of the pressing mechanism 40, an appropriate pressing member that elastically abuts on the outer periphery of the movable ring can be adopted.

As explained above, in the present invention, a pair of engagement slits in the axial direction are formed in diametrically opposite parts of the outer periphery of the movable ring constituting the variable displacement vane pump, and one The slit is engaged with a pivot pin facing one side of the inner hole of the pump housing, and the other engagement slit is engaged with an engagement pin that engages with the pushing member, and the pivot pin of the pump housing is engaged with the pivot pin that faces one side of the inner hole of the pump housing. A pressing member that can move forward and backward relative to the outer periphery of the movable ring is attached to the side via a compression spring and an adjustment screw that can move forward and backward, and the pressing member urges the movable ring toward the engaging pin side. There is a characteristic of its composition. Therefore, according to the present invention, it is possible to use a circular movable ring with a small outer diameter, and it is possible to provide a vane pump that is simple in structure, easy to manufacture, and does not become unnecessarily large. Therefore, it is possible to provide a vane pump in which stable pump operation can be expected without the movable ring vibrating when the pump is started.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of a vane pump according to the present invention, and FIG. 2 is a longitudinal sectional view taken along the line - in FIG. Explanation of symbols, 10... Pump housing, 12
a... Inner hole, 21... Movable ring, 21a, 21
b...Engagement slit, 23...Rotor, 25...
Pivot pin, 26...engaging pin, 31...spool, P...pump chamber, _R3 ...high pressure chamber, _R5 ...low pressure chamber.

Claims (1)

[Scope of utility model registration request] A movable ring that accommodates a rotor having a large number of vanes is accommodated in the inner hole of the pump housing so as to be able to swing in the radial direction via an axial pivot pin provided in the pump housing. The movable ring is oscillated by a pushing member attached to a portion of the movable ring on the opposite side of the pivot portion so as to be movable in the radial direction, thereby changing the amount of eccentricity of the movable ring with respect to the rotor. In the positive displacement vane pump, a pair of engagement slits in the axial direction are formed at mutually opposite parts on the outer circumference of the movable ring, and one engagement slit is engaged with the pivot pin, and the other engagement slit is engaged with the pivot pin. The engagement slit is engaged with the engagement pin that engages the pushing member, and a compression spring and a pushing member that can move back and forth with respect to the outer periphery of the movable ring are attached to the pivot pin side of the pump housing. 1. A variable displacement vane pump, characterized in that the movable ring is assembled through a possible adjustment screw, and the pressing member urges the movable ring toward the engagement pin.