JPS626305Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable displacement vane pump in which the displacement of a movable ring movable in the radial direction is accommodated in an inner hole of a pump housing and whose eccentricity relative to the rotor is varied to vary the discharge capacity.

Conventionally, in this type of variable displacement vane pump, the fluid chamber formed between the inner circumferential wall of the pump housing and the outer periphery of the movable ring is divided into two, and a fixed orifice is provided in the discharge passage communicating with one of the divided chambers. By applying pressure on the downstream side of this orifice to the other compartment, the eccentricity of the movable ring can be changed using the differential pressure before and after the orifice, and this can be applied to fluctuations in rotor rotational speed (pump rotational speed). However, a method has been proposed in which the flow rate of pressure fluid supplied to fluid-operated equipment is controlled to be constant.

However, if the fluid operating device is, for example, a power steering system for a vehicle equipped with a four-way switching control valve, a constant flow of pressurized fluid is supplied even when the steering force is small when the vehicle is running at high speed. This results in a large power loss. Therefore, in a variable displacement vane pump that supplies pressure fluid to such fluid-operated equipment, when the load pressure is extremely small, such as when the fluid-operated equipment is not operating, the pressure fluid is reduced as the pump rotation speed increases. It is desirable to have a function of decreasing the supply flow rate of the fluid and increasing the reduced supply flow rate to a predetermined amount when the load pressure is large, such as when operating a fluid operating device.

This invention was made to deal with this,
The present invention will be explained below based on the drawings. FIGS. 1 and 2 show an example of a variable displacement vane pump according to the present invention.

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 movable ring 2 is disposed inside the guide housing 12.
An inner hole 12a is formed to accommodate a rotor 23 having one vane 22 and a plurality of vanes 22.

The movable ring 21 has a perfect circular shape and is smaller by a predetermined amount than the diameter of the inner hole 12a of the guide housing 12.
It is accommodated in the inner hole 12a so as to be movable in the radial direction, and a fluid chamber R is formed between the peripheral wall of the inner hole 12a and the outer periphery of the movable ring 21. Further, the rotor 23 is spline-fitted to one end of a rotating shaft 24 that is liquid-tightly and rotatably supported by the front housing 11, and is housed inside the movable ring 21 so that the inner circumference of the movable ring 21 and the rotor 23 are connected to each other. A pump chamber P is formed between the outer peripheries. This movable ring 21 is
The screw member 31 screwed on the right side in the second figure and the spring 32 for adjusting the flow rate interposed between the outer periphery of the movable ring 21 bias it to the left in the figure, and the guide housing 12 is screwed on the left side in the second figure. It is in contact with a screw member 33 for regulating the maximum eccentricity. As a result, the movable ring 21 is eccentric to the rotor 23 by the maximum amount.

On the other hand, an intake port 11a and a discharge port 11b are formed on the inner surface of the front housing 11. The suction port 11a communicates with a suction passage 11c provided in the front housing 11 and the suction area of the pump chamber P, and the discharge port 11b communicates with the discharge area of the pump chamber P and the fluid chamber R. Also,
A discharge hole 12b is formed in the guide housing 12, and the discharge hole 12b communicates with the fluid chamber R and a discharge passage (not shown).

A pair of long holes 11d and 14a facing each other are formed in the inner surface of the front housing 11 and the inner surface of the pressure plate 14, and both ends of the seal pin 34 are inserted into these long holes 11d and 14a, respectively. It is fitted. This seal pin 34
extends in the axial direction at an intermediate portion between the openings of the discharge port 11b and the discharge hole 12b, and is in fluid-tight contact with the upper peripheral wall of the inner hole 12a of the guide housing 12. Furthermore, a fitting groove 21a that can be fitted onto the seal pin 34 is formed in the axial direction at a portion of the outer periphery of the movable ring 21 that faces the seal pin 34. This movable ring 21 is pushed upward in the figure by the fluid pressure of the pump chamber P, and the fitting groove 21
a is fitted onto the seal pin 34. As a result, the seal pin 34 supports the movable ring 21 so as to be able to swing against the spring 32, and also seals between the inner hole circumferential wall of the guide housing 12 and the outer circumference of the movable ring 21 at the supporting portion. ing.

On the other hand, a fitting recess 12c extending in the axial direction is formed in the lower peripheral wall of the inner hole 12a of the guide housing 12. This fitting recess 12c has a radial stepped screw hole 12 provided in the guide housing 12.
d are in communication with each other, and a gap adjustment member 35 is accommodated in these fitting recesses 12c and stepped screw holes 12d. The gap adjustment member 35 consists of a head portion 35a having an inclined inner surface and a cylindrical leg portion 35b, and the leg portion 35b is inserted into the stepped screw hole 12d.
When the head 35a is inserted into the fitting recess 12c
fitted inside. This gap adjustment member 35 is
A seat nut 36 is fitted liquid-tightly and slidably onto the leg portion 35b and screwed into the stepped screw hole 12d.
and a fixing nut 37 screwed onto the outer end of the leg 35b, and a spring 38 interposed between the outer surface of the head 35a and the inner surface of the seat nut 36 is attached to the outer peripheral surface of the movable ring 21. It is now possible to advance and retreat responsibly. Further, the inner surface of the head 35a is formed in a shape in which the amount of protrusion into the fluid chamber R gradually increases as it goes to the right in the second figure, and is set at an initial position by a spring 38, and the movable ring 21 An orifice O is formed between the outer circumferential surface of the Therefore, this orifice O is located at the second position of the movable ring 21 when the gap adjustment member 35 is set at the initial position.
The orifice is configured as a variable orifice in which the opening degree of the orifice gradually decreases by swinging toward the right in the figure, that is, in the direction against the spring 32.

As a result, the seal pin 34 and the gap adjustment member 3
5 is a first working chamber r1 in which a discharge port 11b opens the fluid chamber R; and a second working chamber _R1 in which a discharge hole 12b opens.
r ₂ , and these working chambers r ₁ and r ₂ are communicated with each other via a variable orifice O.

In the vane pump configured in this way,
When not driven, the movable ring 21 is eccentric by the maximum amount as shown in FIG. 2, and the orifice opening degree of the variable orifice O is the maximum. Further, when the rotating shaft 24 and the rotor 23 integrated therewith rotate due to the drive of the engine, the fluid sucked into the pump chamber P through the suction passage 11c and the suction port 11a is discharged to the first working chamber r1 through the discharge port _11b . and further through the variable orifice O.
It flows into the working chamber _r2 and is supplied to an appropriate fluid operating device through the discharge hole 12b and a discharge passage (not shown).

By the way, when the internal pressure of the fluid chamber R is below a predetermined value, that is, when the load pressure of the pump is below a predetermined value, such as when a fluid-operated device is not operating, the rotational speed of the rotating shaft 24 and the rotor 23 (pump rotational speed) increases. When the amount of pressure fluid discharged to the first working chamber _r1 increases,
The movable ring 21 is swung against the spring 32 due to the differential pressure generated between the first working chamber r ₁ and the second working chamber r ₂ . Therefore, the amount of eccentricity of the movable ring 21 with respect to the rotor 23 decreases in accordance with the increase in differential pressure caused by the increase in pump rotational speed, and furthermore, the amount of eccentricity of the variable orifice O decreases in accordance with the decrease in the amount of eccentricity of the movable ring 21 described above. The opening degree decreases and both working chambers r ₁ ,
Create a pressure difference between r _{and 2} . As a result, the eccentricity of the movable ring 21 is reduced more than the amount corresponding to the increase in pump rotation speed, and the discharge amount per pump rotation is reduced more than that of conventional vane pumps of this type. Gradually reduce the flow rate of pressure fluid supplied to the operating equipment. That is, the relationship between the rotation speed of the vane pump and the supply flow rate of pressure fluid is as shown in the graph shown by the solid line A in FIG. 3.

Therefore, when the load pressure of the pump increases to a predetermined level or more due to the operation of the fluid-operated device in a state where the supply flow rate of the pressure fluid is reduced, the gap adjustment member 35 is moved by the spring 38 in response to this due to the internal pressure of the fluid chamber R. It resists and is pushed down. Therefore, as the eccentricity of the movable ring 21 decreases, the opening degree of the reduced orifice O is increased as the gap adjustment member 35 is displaced, and as a result, the differential pressure before and after the orifice O decreases, and the The amount of eccentricity is increased, and the flow rate of the pressure fluid supplied to the operating equipment is increased and restored. In other words, the supply flow rate is 2 in Figure 3.
As shown by the dotted chain line B, by increasing the load pressure of the pump, the supply flow rate can be raised to or close to that of the conventional vane pump of this type.

Note that this embodiment shows one embodiment of the present invention, and in the present invention, the shape of the inner surface of the head 35a of the gap adjustment member 35, the initial load of the spring 38,
By appropriately changing the gap between the inner surface of the head 35a and the outer circumferential surface of the movable ring 21, the flow characteristics shown by the solid line A and the two-dot chain line B can be changed to any desired flow characteristics. In addition, the present invention accommodates a rotor having a large number of vanes inside a movable ring that is movably housed in the radial direction in the inner hole of the pump housing, and a spring member that abuts the movable ring on the outer periphery of the movable ring. The fluid chamber formed between the inner circumferential wall of the inner hole of the pump housing and the outer circumference of the movable ring is biased toward one side to make the rotor eccentric by a predetermined amount. The present invention can be applied to various variable displacement vane pumps in which a discharge port communicating with the discharge area of the formed pump chamber and a discharge hole communicating with the outside are respectively opened.

As explained above, the present invention provides the above-described various variable displacement vane pumps with a seal portion between the discharge port and the discharge hole that brings the movable ring into fluid-tight contact with the circumferential wall of the inner hole of the pump housing. an orifice is formed in a recess provided on the side opposite to the sealing portion of the inner hole circumferential wall of the pump housing, facing the outer periphery of the movable ring, and in a direction that opposes the spring member of the movable ring; Its structural feature lies in that a gap adjustment member shaped to reduce the opening degree of the orifice in accordance with the displacement of the movable ring is spring-biased toward the outer periphery of the movable ring and is assembled so as to be movable forward and backward relative to the outer periphery. . Therefore, according to the present invention, when the load pressure is extremely small, such as when a fluid-operated device is not operating, the supply flow rate of pressure fluid is reduced in accordance with an increase in pump rotation speed, and when the fluid-operated device is operating, etc. When the load pressure is large, a function can be provided to increase the reduced supply flow rate to a predetermined amount.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of a vane pump according to the present invention, FIG. 2 is a longitudinal sectional view taken along the line - in FIG. 1, and FIG. 3 is a graph showing flow characteristics of the vane pump. Explanation of symbols, 10... Pump housing, 11
a...Suction port, 11b...Discharge port, 12
a... Inner hole, 12b... Discharge hole, 12c... Fitting recess, 21... Movable ring, 23... Rotor, 3
2, 38...Spring, 34...Seal pin,
35... Gap adjustment member, O... Orifice, P...
...Pump chamber, R...Fluid chamber.

Claims (1)

[Scope of utility model registration request] A rotor having a large number of vanes is housed inside a movable ring that is movable in the radial direction within the inner hole of the pump housing, and the movable ring is biased to one side by a spring member that is in contact with the outer periphery of the movable ring. a fluid chamber formed between the inner circumference of the inner hole of the pump housing and the outer circumference of the movable ring and between the inner circumference of the movable ring and the outer circumference of the rotor. In a variable displacement vane pump having a discharge port that communicates with a discharge area of a pump chamber and a discharge hole that communicates with the outside, the movable ring is inserted between the discharge port and the discharge hole in the inner hole of the pump housing. A seal portion is provided in close contact with the peripheral wall in a fluid-tight manner, and an orifice is formed in a recess provided on the opposite side of the inner hole peripheral wall of the pump housing to the outer periphery of the movable ring. A gap adjustment member having a shape that reduces the opening degree of the orifice in response to displacement of the movable ring in a direction opposing the spring member is spring-biased toward the outer periphery of the movable ring and assembled so as to be movable toward and away from the outer periphery. A variable displacement vane pump characterized by the following: