JP2000054969A - Variable displacement pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a flow characteristic in a variable displacement pump which uses a pin as an oscillation fulcrum of a cam ring. SOLUTION: This pump is provided with a cam ring 17 that is engaged so as to form a pump chamber with an outer periphery near one side of a rotor 15 which has a vane 15a and is rotatable in a pump body, is arranged oscillatably by an oscillation fulcrum pin 21 in the pump body, and is energized in the direction that volume of the pump chamber becomes maximum. The oscillation fulcrum pin is supported by a recessed part 51 formed in the inner wall of an adapter ring 19, a cam ring accommodating portion of the pump body. Both ends of this oscillation fulcrum pin are inserted into substantially elliptical shaped oblong holes 52, 52 formed in a rear body 12 and a pressure plate 20 which are plates for sandwiching a pump component element from its both sides.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement vane pump used in a pressure fluid utilizing device such as a power steering device for reducing a steering force of a vehicle.

[0002]

2. Description of the Related Art As a pump for a power steering device, a displacement type vane pump directly driven and rotated by an automobile engine has been generally used. Since the displacement flow rate of such a displacement pump increases or decreases in response to the engine speed, the power assisted steering increases the steering assist force when the vehicle is stopped or running at low speed, and decreases the steering assist force during high speed running. It has a characteristic opposite to the steering assist force required for the device. Therefore, it is necessary to use a large-capacity pump capable of ensuring a discharge flow rate such that a necessary steering assist force can be obtained even at a low speed running at a low speed. Moreover, for high-speed driving with high rotation speed,
A flow control valve for controlling the discharge flow to a certain amount or less is essential. For this reason, in the displacement pump, the number of components is increased, the structure and the passage configuration are complicated, and it is inevitable that the overall size and cost increase.

In order to solve such a problem of the displacement pump, a variable displacement vane pump capable of decreasing the discharge flow rate per one rotation (cc / rev) in proportion to an increase in the number of rotations has been proposed. JP-A-53-13050
No. 5, JP-A-56-143383, Japanese Utility Model Publication No. 6
It has been proposed in Japanese Unexamined Patent Publication No. 3-14078 and Japanese Unexamined Patent Publication No. Hei 7-243385. According to these variable displacement pumps, a flow control valve such as a displacement pump is not required, and since the driving horsepower can be prevented from being wasted, the pump is excellent in energy efficiency.
In addition, since there is no return to the tank side, the oil temperature does not increase, and furthermore, the problem of leakage inside the pump and reduction of volumetric efficiency can be prevented.

An example of a vane type oil pump 10 serving as a hydraulic pressure source of a power steering device as such a variable displacement vane pump will be briefly described with reference to FIGS. 3 and 4. A pump body includes a front body 11 and a rear body 12. As is apparent from FIG. 4, the front body 11 has a substantially cup-like shape as a whole, and a storage space 14 for storing and arranging a pump component 13 as a pump cartridge is formed therein. The rear body 12 is combined and integrated so as to close the open end. The front body 11 has
Bearings 16a, 16b, 16c (16b is on the rear body 12 side, 16c is a pressure plate 20 described later) in a state where a drive shaft 16 for rotationally driving a rotor 15 as a rotor of the pump component 13 from the outside penetrates.
(Disposed on the side).

[0005] Reference numeral 17 denotes an inner cam surface 17a which is fitted and disposed on the outer peripheral portion of the rotor 15 having the vane 15a.
The cam ring forms a pump chamber 18 between the inner cam surface 17a and the rotor 15. This cam ring 1
As described later, 7 is arranged so as to be swingably displaceable in an adapter ring 19 provided in a fitting state on the inner wall portion of the space in the storage space 14 so as to change the volume of the pump chamber 18. The adapter ring 19 is attached to the body 11
This is for holding the cam ring 17 so as to be able to swing and displace in the storage space 14 of this embodiment. The adapter ring 19 can be omitted and the cam ring 17 can be held so as to be able to swing and displace directly in the body 11.

Reference numeral 20 denotes the rotor 15 and the cam ring 1 described above.
The pressure plate is a pressure plate which is stacked by being pressed against the front body 11 side of a pump cartridge (pump component 13) constituted by the pump cartridge 7 and the adapter ring 19. The end face of the rear body 12 is pressed against the opposite side face of the pump cartridge as a side plate,
A required assembly state is obtained by integrally assembling the front body 11 and the rear body 12. The pump component 13 is constituted by these members.

The pressure plate 20 and the rear body 12 serving as a side plate laminated on the pressure ring 20 via the cam ring 17 are provided with a swing support for the swing displacement of the cam ring 17, a positioning pin and a seal pin described later. The movable fulcrum pin 21 and an appropriate detent means (not shown) integrally assemble and fix it while being positioned in the rotational direction.

Reference numeral 23 denotes a pump discharge side pressure chamber formed at the bottom of the storage space 14 of the front body 11, and the pump discharge side pressure acts on the pressure plate 20 by the pressure chamber 23. Reference numeral 24 denotes a pump discharge side opening which is opened in the pump discharge side pressure chamber 23 in the pump discharge side area 18B of the pump chamber 18 and is formed in the pressure plate 20 so as to guide pressure oil from the pump discharge side area 18B.

Reference numeral 25 denotes a pump suction port provided in a part of the front body 11 as shown in FIG. 4. The suction side fluid flowing from the suction port 25 passes through a valve hole 30a of a control valve 30, which will be described later. As a result, the pump suction side passage 25a formed in the front body 11 and the passages 25b, 25 formed in the rear body 12 continuously therewith.
c through the pump suction side opening 26 opening at the end face of the rear body 12 to the pump suction side area 18A of the pump chamber 18.
Supplied to

Reference numeral 28 denotes a discharge port opened by a plug 28a provided on the side of the front body 11. The discharge port 28 is provided with a pump passage 18, a pump discharge side pressure chamber 23, a fluid passage hole 29 formed at a different position of the pressure plate 20 from the pump chamber 18, a second fluid pressure chamber 37 described later, A spring chamber 4 formed by a plug 42 for accommodating a spring 41 for urging the cam ring 17
2a, a notch groove 43 formed in the front body 11, and a pump discharge-side fluid pressure fed through passage holes 44, 45, and 28b formed in the body 11, and a power steering device (not shown) indicated by PS. ) And other hydraulic equipment.

The above-mentioned pump discharge side passages (24, 23,
29, 42a, 43, 44, 45, 28b)
A variable metering orifice 40 capable of increasing or decreasing the opening area is formed by the fluid passage hole 29 opening to the second fluid pressure chamber 37 and the side surface of the cam ring 17.
This variable metering orifice 40 is
The passage hole 29 is opened and closed by the side wall portion in accordance with the swing displacement of 7. The orifice 40
Is formed in an appropriate shape whose opening and closing amount is controlled in accordance with the magnitude of the fluid pressure on the pump discharge side.
Can be controlled to a desired state, and the flow characteristics can be diversified.

Reference numeral 30 denotes a control valve arranged substantially orthogonally above the storage space 14 in the front body 11. The control valve 30 is connected to the pump discharge side passage (24, 2) in a valve hole 30a formed in the body 11.
3, 29, 42a, 43, 44, 45, 28b) A spool 3 which slides on the variable metering orifice 29 provided in the middle thereof by the pressure difference on the downstream side and the urging force of the spring 31.
2 is provided. The control valve 30 controls the fluid pressure control for causing the cam ring 17 to swing and displace with respect to the rotor 15 in the pump body 11 (adapter ring 19) in the variable metering orifice 4 described later.
Perform by 0.

In this control valve 30, the spool 3
The fluid pressure upstream of the variable metering orifice 40 is connected to one chamber (left chamber in FIG. 3) 32a through fluid passages 46 and 47 extending from the pressure chamber 23 on the pump discharge side. Has been led. In the figure, reference numeral 33 denotes a valve hole 3
0a, the position to which the spool 32 moves to the left
7 is a plug for closing the valve hole 30a having the rod 33a that locks the open end of the opening 7 at a position where it is not closed.

A spring 31 is provided in the other chamber (the right chamber in FIG. 3) 32b of the spool 32, and a fluid pressure downstream of the variable metering orifice 40 reaches the discharge port 28. In the middle, that is, from the second fluid pressure chamber 37, the fluid is guided through the fluid passage 19a formed between the body 11 and the adapter ring 19 and the fluid passage 34 formed in the body 11. The valve hole 30a
As described above, a pump suction side passage 25a continuous with the suction port 25 is formed through the substantially central portion of the spool 32, and the suction side fluid is supplied through an annular space formed by the annular groove 32c of the spool 32. Is done.

A first fluid pressure chamber (described later) formed between the adapter ring 19 and the cam ring 17 is provided between the opening of the suction side passage 25a and the opening of the fluid passage 47 on the discharge side. The fluid passage 19b of the adapter ring 19 and the fluid passage 3 drilled in the body 11
5 are open, and normally, as shown in FIG.
Thereby, it communicates with the pump suction side passage 25a and introduces the fluid pressure on the suction side into the first fluid pressure chamber 36. When the spool 32 moves to the right by a predetermined amount or more, the spool 32 is disconnected from the pump suction side, and the fluid pressure on the pump discharge side is supplied to the first fluid pressure chamber 36. In the drawing, reference numeral 34a denotes a damper orifice portion.

Reference numerals 36 and 37 denote an outer peripheral portion of the cam ring 17 and an inner peripheral portion of the body 11 (adapter ring 19) by a swing fulcrum pin 21 and a seal member 38 provided at a position substantially symmetrical with the pivot. The first and second fluid pressure chambers formed to be divided to the right and the first and second fluid pressure chambers actuate the first
In the fluid pressure chamber 36, the fluid pressure on the pump suction side or the pump discharge side upstream of the variable metering orifice 40 is
In the fluid pressure chamber 37, the pump discharge side fluid pressure downstream of the variable metering orifice 40 is introduced. Here, on the outer peripheral portion of the cam ring 17, it is preferable to form a concave groove or the like of about half a circumference along the circumferential direction so that the first fluid pressure chamber 36 can be secured even when the first fluid pressure chamber 36 contacts the adapter ring 19. .

The fluid passage hole 29 constituting the variable metering orifice 40 is raised so that a predetermined flow rate can be obtained when the rotational speed is low, due to an opening area that changes when the cam ring 17 closes the fluid passage hole 29. Is increased, the flow rate is reduced, and at a predetermined rotational speed or more, a flow rate of about half of the initial flow rate is obtained. FIG. 5 shows such flow characteristics.
(A). In the vane type variable displacement pump 10 as described above, the configuration other than the above-described configuration is conventionally known, and a specific description thereof will be omitted.

The vane pump 10 constructed as described above
According to this, when the rotor 15 is rotationally driven by the drive shaft 16 while moving the vanes 15a in and out, the pressure oil, which is the working fluid from the suction port 25, is passed through the passages 25a, 25b, 25c and the opening 26 to the pump chamber. 18
After being sucked into the inside and being sent out from the discharge side passage 24 to the pump discharge side pressure chamber 23, it is discharged from the discharge port 28 and fed to the power steering device PS and the like.

The above-described control valve 30 is operated by a differential pressure on the downstream side of the variable metering orifice 40 provided in the middle of the pump discharge side passage, and controls the fluid pressure according to the magnitude of the flow rate on the pump discharge side. By introducing the cam ring 17 into the first and second fluid pressure chambers 36 and 37 at the outer portion of the cam ring 17, the cam ring 17 is displaced by swinging, and the pump chamber 1 is displaced.
Keep the volume of 8 at the required size.

For example, when the engine speed is low, the cam ring 17 is kept displaced to the left in FIG. 3, and the pump chamber 18 is kept at the maximum volume. As a result, the discharge flow rate from the pump 10 increases as the rotation speed increases in FIG. Then, when the rotation speed increases and the pump discharge flow rate becomes a certain amount or more, the cam ring 17 is rocked to the right in FIG.
The volume of the pump chamber 18 is reduced, so that the pump discharge flow rate is kept constant. Further, the displacement of the cam ring 17 is controlled by gradually closing the variable metering orifice 40 with the swing of the cam ring 17,
The flow rate of the pump is reduced, and the flow rate becomes about half of the initial flow rate at a predetermined rotation speed or more.

[0021]

In the conventional variable displacement vane pump 10 as described above, the cam ring 17 which can swing and displace within the pump body (adapter ring 19) is shown in FIGS. 3, 4 and 6. As shown, holes (a perfect circular hole having a diameter substantially equal to the outer diameter of the pin 21) 12a provided in the rear body 12 and the pressure plate 20 are provided.
It was supported by a swing fulcrum pin 21 provided with both ends fitted in 20a. The load of the cam ring 17 is received by engaging the concave portion 17 d formed on the outer peripheral portion of the cam ring 17 with the swing fulcrum pin 21.

A concave portion 19d is also formed in the inner peripheral portion of the adapter ring 19 corresponding to the above-mentioned swing fulcrum pin 21. As described above, the shaft is formed in the holes 12a and 20a of the rear body 12 and the pressure plate 20. As shown in FIG. 6, a gap is formed between the outer peripheral portion of the pin 21 supported and the groove bottom of the concave portion 19d.

The rocking fulcrum pin 21 has a positioning function for positioning the rear body 12 and the pressure plate 20 in the rotational direction. However, if the concentricity of the holes 12a and 20a formed in these pins shifts, the pin 21 is moved. The cam ring 17 that has fallen from the normal posture and is supported by the pin 21 also has the pin 21 as shown by the arrow in FIG.
There is a possibility that the other end portion may fall down in the axial direction in accordance with the posture of (1).

When the cam ring 17 is in such an inclined state, a part of the cam ring 17 comes into contact with the rear body 12 and the pressure plate 20 when the cam ring 17 tries to swing by the variable metering orifice 30 and the control valve 30. In some cases, the cam ring 17 could not be smoothly swung due to catching. In such a state, the discharge flow rate from the pump 10 intermittently increases and decreases as shown by the middle dashed line in FIG.

In the swing fulcrum pin 21 as described above, portions other than the shaft support portions at both ends are formed in the adapter ring 19.
When a load acts on the cam ring 17 from inside, there is a possibility that the cam ring 17 may be curved by the outer peripheral portion as shown by imaginary lines in FIG. When deformed in this manner, a part of the swing fulcrum pin 21 slides on the inner walls and edges of the holes 12a and 20a of the rear body 12 and the pressure plate 20, and the movement of the swing fulcrum pin 21 and the cam ring 17 is hindered. There was also a possibility that it could be done. Further, according to such a swing fulcrum pin 21, there is a problem that the pin 21 and the holes 12a and 20a are worn.

Further, according to the swing fulcrum pin 21 described above, since all the loads acting on the cam ring 17 are received, the holes 12 of the rear body 12 and the pressure plate 20 are formed.
Since there is a space restriction in the portions a and 20a, the strength is likely to be insufficient in this portion, and there is a possibility that the pivot portion of the oscillating fulcrum pin 21 may be damaged, and it is not possible to increase the pressure of the pump. There were also problems.

Further, according to the variable displacement pump 10 described above, the cam ring 17 is swingably supported at a position deviated from the rotor 15, and the pump chamber 18 is disposed at a position deviated toward one side of the rotor 15. Since it is formed, the load acting on the swing fulcrum pin 21 via the cam ring 17 often acts unbalanced from a plurality of directions, and has a fluctuation range, so that the cam ring 17 is supported and the cam ring 17 is smoothly moved. There was also a problem that it was difficult to obtain a swing operation.

The present invention has been made in view of such circumstances, and in a variable displacement pump using a swing fulcrum pin as a swing fulcrum of a cam ring, it is possible to prevent the jumping phenomenon of the flow rate which has conventionally occurred when necessary. It is an object of the present invention to provide a variable displacement pump capable of improving the flow rate characteristics of the pump from the shaft and improving the workability and assemblability of the supporting portion of the swing fulcrum pin.

[0029]

In order to meet such a demand, a variable displacement pump according to the present invention comprises a rotor having vanes and rotatable within a pump body, and an outer peripheral portion near one side of the rotor. And a cam ring that is fitted to form a pump chamber between the pump ring and a rocking fulcrum pin in the pump body so as to be swingably displaceable and urged in a direction to maximize the pump chamber volume. The fluid pressure before and after the variable metering orifice provided in the middle of the discharge side passage of the pressure fluid discharged from the pump chamber is provided between the outer periphery of the cam ring and the pump body via a sealing means. In the variable displacement pump which varies the pump discharge flow rate by introducing the first and second fluid pressure chambers formed separately, the swing fulcrum pin is housed in the cam ring of the pump body. While supporting the recess formed on the inner wall, both end portions of the swing fulcrum pin, characterized in that the pump components were engaged into the elongated hole of approximately oval shape formed on the plates for sandwiching from both sides.

Also, the variable displacement pump according to the present invention
The substantially oval elongated holes into which both ends of the swing fulcrum pin are engaged are opposed to each other with the outer diameter of the swing fulcrum pin being substantially parallel to the direction of the load acting on the inner peripheral portion of the cam ring. Characterized in that it is formed in a shape having a parallel portion. Further, in the variable displacement pump according to the present invention, a concave portion for supporting the swing fulcrum pin is formed in an inner peripheral portion of an adapter ring provided in the pump body, and both ends of the swing fulcrum pin are connected. An oval long hole to be inserted is provided in the inner wall portion of the pump body and the pressure plate which sandwich the pump component from the side to be inserted.

According to the present invention, most of the longitudinal direction of the swing fulcrum pin for supporting the cam ring so as to be able to swing and displace is supported by the concave portion provided on the inner wall of the cam ring housing portion of the pump body. Both ends are escaped and held by substantially oval long holes formed in both side plates sandwiching the pump component.

The variable displacement pump is a vane type oil pump that discharges hydraulic pressure, and is used as, for example, a hydraulic power source in a power steering device of an automobile, but is not limited thereto. The cam ring is swingably supported by a swing fulcrum pin which partially becomes a support shaft in a space provided in the pump body, and first cams provided on both sides of a line passing through the swing fulcrum pin.
And the fluid pressure in the second fluid pressure chamber and the urging means attached to the fluid pressure chamber on the lower pressure side of the second fluid pressure chamber perform an oscillating operation.

The case where the control valve for controlling the fluid pressure for swinging the cam ring is used has been described. However, the present invention is not limited to this case. The cam ring may be configured to swing and displace in response.

[0034]

1 and 2 show one embodiment of a variable displacement pump according to the present invention. In these figures, the same or corresponding parts as those in FIG. And a detailed description thereof will be omitted.
FIGS. 1A, 1B, and 1C are enlarged views of a portion of the cam ring 17 provided with the pivot fulcrum pin 21 as in FIG. The relationship is exaggerated for clarity.

According to the present invention, in the variable displacement vane pump 10 described above, the swing fulcrum pin 21 for swingably displacing the cam ring 17 in the pump body (adapter ring 19) is connected to the adapter ring. The holes supported by the concave portions 51 formed in the inner peripheral portion of the pump 19 and engaging both ends of the swing fulcrum pin 21 are formed on both sides of the plate (in the rear body 12) that sandwich the pump component 13 in the pump body. A substantially oval long hole 5 formed in the side plate on the side surface and the pressure plate 20)
2, 52.

That is, the conventional swing fulcrum pin 21 is supported by circular holes formed in the inner surface of the rear body 12 on both sides of the pump component 13 and the pressure plate 20, and is formed by a concave portion on the adapter ring 19 side. However, in the present invention, the swing fulcrum pin 21 is directly received and supported by the concave portion 51 of the adapter ring 19, and both ends are configured to be movable.

According to such a configuration, the swing fulcrum pin 2
Most of the longitudinal direction 1 is held by the groove bottom 51a of the concave portion 51 and serves as a swing fulcrum of the cam ring 17 and a seal pin between the first and second fluid pressure chambers 36 and 37. Functions as a positioning pin.

The long holes 52, 52 into which both ends of the swing fulcrum pin 21 are engaged, swing against a load caused by a discharge pressure or the like in the discharge side area 18B of the pump chamber 18 acting via the cam ring 17. The movable support pin 21 is formed as a long hole that allows the end portion to move. Note that FIG.
(B) The direction of the load acting on the swing fulcrum pin 21 is indicated by a middle arrow and acts with a slight variation width. For example, when the diameter of the swing fulcrum pin 21 is 3φ, the long diameter portion of the substantially oval long hole 52 is 3.3 m.
It has been confirmed that m should be set.

Of course, the oblong holes 52, 52
Are parallel portions 52a and 52b facing each other with a gap corresponding to the outer diameter of the swing fulcrum pin 21 so that the rotation direction of the rear body 12 and the pressure plate 20 can be determined.
And the dimension in the short side direction is determined. In addition,
These parallel portions 52a and 52b extend in the direction in which the discharge pressure in the discharge side region 18B of the pump chamber 18 acts on the cam ring 17.

According to such a configuration, the swing fulcrum pin 2
1 can be supported by the concave portion 51 of the adapter ring 19,
Function as a swing fulcrum can be secured. Then, regardless of the load acting via the cam ring 17 due to the effect of the fluctuating fluid pressure in the pump discharge side area 18B in the pump chamber 18 which is a conventional problem, the pin 21 does not fall down and the cam ring 17 is removed. Since the swing displacement can be smoothly performed, the jumping phenomenon of the flow rate can be prevented.

Also in the flow rate adjustment region where the pump discharge flow rate is adjusted by the swing displacement of the cam ring 17, the cam ring 17 swings smoothly, so that the flow rate characteristics of the pump can be stabilized. Further, according to the above-described configuration, the holes into which both ends of the swing fulcrum pin 21 are engaged are elongated holes 52, 52 elongated in the direction in which the load is applied to the cam ring 17.
, The rear body 12,
The problem of strength at the pin support portion of the pressure plate 20 can be solved. Further, since the supporting strength of the swing fulcrum pin 21 is increased in addition to this, the pump 1
0 can be increased.

It should be noted that the present invention is not limited to the structure of the above-described embodiment, and that the shape, structure, etc. of each part can be freely modified and changed as appropriate, and various modifications are conceivable. For example, in the embodiment described above, the front body 11 and the rear body 1 are used as the pump bodies of the variable displacement pump 10.
However, the present invention is not limited to this, and may be a three-body pump body having an intermediate body.

Further, in the above-described embodiment, the case where the annular gap space for holding the cam ring 17 so as to be capable of swinging displacement is formed between the adapter ring 19 and the present invention is not limited to this. , Omitting the adapter ring 19,
In the pump body, the cam ring 17 may be directly held on the inner peripheral portion of the front body 11 or the inner peripheral portion of the intermediate body so as to be swingably displaceable.

Further, in the above-described embodiment, the case where the rotor 15, the cam ring 17, and the adapter ring 19 (pump body) are interposed between the rear body 12 provided as a pump body and the pressure plate 20 opposed thereto. Although described, the invention is not limited to this,
A side plate may be interposed inside the rear body 12.

In the above-described embodiment, the swinging fulcrum pin 21 and the rear body 12 and the pressure plate 2
Although the case of positioning in the rotation direction of 0 has been described, the present invention is not limited to this, and an appropriate positioning pin may be separately provided.

Further, in the above-described embodiment, the variable displacement pump 10 having the structure in which the swing displacement of the cam ring 17 is controlled using the control valve 30 has been described.
The present invention is not limited to this, the control valve 30 is omitted,
The present invention is also applicable to a type in which a cam ring is swung by a load pressure on a pressure fluid utilization device side. In addition, the vane type variable displacement pump 10 having the above-described configuration is not limited to the structure in the above-described embodiment, and various devices other than the power steering device described in the above-described embodiment may be used. You may apply to an apparatus.

[0047]

As described above, according to the variable displacement pump of the present invention, the swing fulcrum pin can be reliably supported, and the swing fulcrum pin due to the load applied from the cam ring side, which has been a problem in the prior art, can be attained. It is possible to solve the problem of the cam ring swinging displacement due to the falling or bending, the falling of the cam ring, and the like. Further, according to the present invention, it is possible to secure a smooth swing displacement of the cam ring, to eliminate a jumping phenomenon of the flow rate as in the related art, and to stabilize the flow rate characteristics.

Further, according to the present invention, it is possible to solve the problem of the strength at the supporting portions of the swing fulcrum pins in the plates on both sides which sandwich the pump component, and it is possible to increase the pressure of the pump. ADVANTAGE OF THE INVENTION According to this invention, the swing displacement operation | movement of a cam ring is improved so that it may become smooth, and, thereby, the flow characteristic of a pump can be improved.

[Brief description of the drawings]

FIG. 1 shows one embodiment of a variable displacement pump according to the present invention, and FIG. 1 (a) is an enlarged cross-sectional view of a swinging fulcrum pin supporting portion structure, which characterizes the present invention, is exaggerated compared to an actual case. , (B) and (c) show the Ib-Ib line of (a) and Ic-I
It is a c-line sectional view.

2A is a cross-sectional view of a variable displacement pump adopting the present invention, and FIG. 2B is an enlarged view of a main part thereof.

FIG. 3 is a cross-sectional view showing a main structure of a conventional variable displacement pump.

4 is a cross-sectional view taken along line IV-IV in FIG. 3 of the conventional variable displacement pump.

FIG. 5A is a characteristic diagram showing a flow rate characteristic of a variable displacement pump, and FIG. 5B is a characteristic diagram for explaining a conventional problem.

FIG. 6 is an enlarged cross-sectional view of a conventional variable displacement pump in which a supporting portion for supporting a cam ring so as to be able to swing is exaggeratedly drawn.

[Explanation of symbols]

10: Vane type variable displacement pump, 11: Front body (pump body), 12: Rear body, 13 ...
Pump components, 14 ... storage space, 15 ... rotor, 15
a: vane, 16: drive shaft (rotary axis), 17
... Cam ring, 17a ... Cam surface, 18 ... Pump chamber, 19
... Adapter ring, 20 ... Pressure plate, 21 ...
Swing fulcrum pin, 23: pump discharge side pressure chamber, 24: passage serving as pump discharge side opening, 25: suction port, 25a,
25b: pump suction side passage, 26: pump suction side opening,
28: pump discharge port, 28a, 28b: pump discharge side passage, 29: hole constituting variable metering orifice, 30: spool type control valve, 31: spring, 32
... Spool, 32a ... One chamber, 32b ... Other chamber, 34 ...
Fluid passage, 34a damper orifice, 35 fluid passage, 36, 37 first and second fluid pressure chambers, 40 variable metering orifice, 51 recess, 52 52 oval oblong hole, 52a, 52b ... Parallel part.

Continued on the front page F term (reference) 3H040 AA03 BB01 BB09 BB11 CC00 CC14 CC16 CC20 CC22 DD06 DD37 DD40 3H044 AA02 BB05 BB08 CC00 CC12 CC14 CC18 CC27 DD04 DD24 DD28 DD35

Claims (4)

[Claims] An oscillating fulcrum in a pump body is fitted between a rotor having a vane and rotatable within a pump body and an outer peripheral portion near one side of the rotor to form a pump chamber. A cam ring oscillated by a pin and urged in a direction in which the volume of the pump chamber is maximized, and a variable meter provided in the middle of a discharge-side passage for a pressure fluid discharged from the pump chamber. By introducing the fluid pressure before and after the ring orifice into first and second fluid pressure chambers formed separately between the outer circumference of the cam ring and the pump body via a sealing means, the pump discharge flow rate is increased. In the variable displacement pump, the swing fulcrum pin is supported by a concave portion formed on the inner wall of the cam ring housing portion of the pump body, and both ends of the swing fulcrum pin are Variable displacement pump, characterized in that is engaged into the elongated hole of approximately oval shape formed on the plate for sandwiching the pump components from both sides. 2. The variable displacement pump according to claim 1, wherein the substantially oval elongated holes into which both ends of the swing fulcrum pin are engaged are opposed to each other with the outer diameter dimension of the swing fulcrum pin. A variable displacement pump formed in a shape having a parallel portion substantially parallel to a direction of a load acting on an inner peripheral portion of the cam ring. 3. The variable displacement pump according to claim 1, wherein the concave portion for supporting the swing fulcrum pin is formed in an inner peripheral portion of an adapter ring provided in the pump body. Variable displacement pump. 4. A variable displacement pump according to claim 1, 2 or 3, wherein a substantially oval long hole into which both ends of the swing fulcrum pin are engaged is sandwiched between pump components. A variable displacement pump provided on an inner wall portion of a pump body and a pressure plate sandwiched from a side.