JPH1193861A - Variable-displacement pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of part items of a pump structure and machining man-hours, to improve the machining property and assembling property, to reduce cost, and to make a pump small-sized and lightweight. SOLUTION: This variable-displacement pump is provided with a cam case 23 rockably supporting a cam ring 34 fitted on a rotor 33 having vanes 33a and forming a pump chamber 36 between it and an outer peripheral face while a rocking pin 35 arranged along the axial direction serves as a fulcrum and serving as an intermediate body. A front body and a rear body forming a pump body and journalling the rotary shaft 40 of the rotor 33 are arranged on both end sides in the axial direction of the cam case 23. A coil spring 37 serving as an exciting means exciting the cam ring 34 provided on the second fluid pressure chamber 39 side within the first and second fluid pressure chambers 38, 39 rocking the cam ring 34 in the direction to maximize the pump chamber volume is provided in a hole section 94 bored from the outer surface of the cam case 23, and a discharge side connector 95 forming a discharge port 59 of pressure oil on the pump discharge side is provided on the hole section 94.

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 for a device utilizing pressure fluid, such as a power steering device for reducing a steering force of an automobile.

[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, JP-A-56-143383
JP-A-8-93978, JP-B-63-14078, JP-A-5-278622, JP-A-7-243
385, for example. According to these variable displacement pumps, a flow control valve unlike the displacement type is not required, the driving horsepower is prevented from being wasted, so that energy efficiency is excellent, and since there is no return to the tank side, the oil temperature is reduced. It is possible to prevent a problem that the pump does not rise, and that a leak inside the pump and a decrease in volumetric efficiency are prevented.

An example of such a variable displacement vane pump will be briefly described with reference to FIG. 16 showing a pump structure in Japanese Patent Application Laid-Open No. Hei 7-243385. In FIG. Is this body 1
Oval space 1b formed in the adapter ring 1a
A cam ring is provided so as to be swingable via a support shaft portion 2a serving as a swing support point, and is urged by urging means (compression coil spring) which presses the cam ring in a direction indicated by a white arrow F in the drawing. . Reference numeral 3 denotes a rotor, which is a vane 3a that is housed eccentrically near the other side so as to form a pump chamber 4 in the cam ring 2 on one side, and is rotatably driven by an external drive source so as to be able to advance and retreat in the radial direction. Let go. In addition, 3b in the figure
Is a drive shaft of the rotor 3, and the rotor 3 is rotationally driven in a direction indicated by an arrow in the figure.

[0005] Reference numerals 5 and 6 denote a pair of high-pressure and low-pressure fluid pressure chambers formed on both sides of the outer peripheral surface of the cam ring 2 in the elliptical space 1b of the adapter ring 1a of the body 1. 6, passages 5a and 6a for guiding fluid pressure before and after a variable orifice 12 provided in a pump discharge side passage 11 as a control pressure for swinging the cam ring 2 are opened through a spool type control valve 10 described later. doing. The pump discharge side passage 1 is formed by these passages 5a and 6a.
By introducing the fluid pressure before and after the variable orifice 12, the cam ring 2 is swung in a required direction to change the volume in the pump chamber 4, and the discharge flow rate is controlled according to the flow rate on the pump discharge side. I do. That is, the flow rate control on the discharge side is performed so as to decrease the flow rate on the discharge side as the pump rotation speed increases.

Reference numeral 7 denotes a pump suction side area 4 of the pump chamber 4.
A pump suction side opening (suction port) opened toward A, and a pump discharge side opening (discharge port) 8 opened toward the pump discharge side area 4B of the pump chamber 4. These openings 7 and 8 are formed in either a pressure plate or a side plate (not shown) which is a fixed wall portion for holding and holding a pump component including the rotor 3 and the cam ring 2 from both sides. ing. The cam ring 2 is biased by a compression coil spring from the fluid pressure chamber 6 side as shown by F in the figure, and is pressed in a direction to maintain the volume in the pump chamber 4 to the maximum. In the drawing, reference numeral 2b denotes a seal member provided on the outer peripheral surface of the cam ring 2 to define the fluid pressure chambers 5 and 6 on both the left and right sides together with the shaft support 2a.

Reference numerals 7a and 8a denote whisker-shaped notches formed continuously at the ends of the pump suction side opening 7 and the pump discharge side opening 8 in the direction of pump rotation. These notches 7a and 8a are provided with the respective vanes 3a as the rotor 3 rotates.
When the pumping action is performed by sliding the tip of the cam ring 2 against the inner peripheral surface of the cam ring 2, the space between the vanes approaching the ends of the openings 7 and 8 and the space between the vanes adjacent to the vanes are required. During this period, the fluid pressure is gradually released from the high pressure side to the low pressure side to reduce surge pressure and pulsation due to the surge pressure.

The spool type control valve 10 is actuated by differential pressures P1 and P2 before and after a variable metering orifice 12 provided in the middle of a pump discharge side passage 11, and a fluid corresponding to the flow rate of the pump discharge side. The pressure P3 is introduced into the fluid pressure chamber 5 on the high pressure side outside the cam ring 2 so that a sufficient flow rate can be secured at the initial stage of the operation of the pump. In particular, such a control valve 10 provides a fluid pressure upstream of the variable orifice 12 when the differential pressure across the variable orifice 12 becomes greater than or equal to a predetermined value during a load action by the operation of the pressure fluid utilization device. By introducing P1 as a control pressure into the high-pressure-side fluid pressure chamber 5 outside the cam ring 2, the cam ring 2 can be prevented from swinging.

[0009]

According to the conventional variable displacement vane pump having the above structure, the structure of each part including the pump body 1 is complicated, the number of components is large, and the workability and assembly of each part are increased. However, there is a problem in that it is difficult to reduce the size and weight of the pump as a whole, and there is still room for improvement.

[0010] In the conventional variable displacement pump, for example, Japanese Patent Application Laid-Open Nos. Hei 8-21375 and Hei 8-20023
No. 9 and the like, a discharge port from a pump is formed on both sides of a cam ring 2 with reference to a support shaft 2a in an adapter ring 1a provided in a pump body 1, and first and second fluid pressures are formed. A passage hole serving as a pump discharge side passage is connected to a part of the second fluid pressure chamber 6 which is a low pressure side of the chambers 5 and 6, and a pump is provided from a discharge port provided at an appropriate position of the body 1 to the outside of the pump. It is configured to send out the discharge side pressure oil.

Such a structure is adopted because a coil spring for biasing the cam ring 2 in the direction in which the volume of the pump chamber 4 is maximized in the adapter ring 1a is arranged on the side. This is because the discharge ports are formed in a part of the pump body 1 while being shifted. However, in such a structure, the number of holes to be drilled in the body 1 is increased, which is a problem in terms of workability. There are many members that protrude outward, which is a problem in reducing the size of the pump, and it is desired to take some measures that can solve these problems.

As described above, in the above-described variable displacement pump, the overall structure of the pump is reviewed, the structure of each part is simplified, the number of components is reduced, workability and assemblability are improved, and the pump is improved. Ensuring operational reliability,
There is a need to take some measures that can reduce the size, weight, and cost of the pump.

In view of such circumstances, the present invention reviews the overall structure of the pump including the pump body, fundamentally improves the structure of the pump body, reduces the number of components, and reduces the number of processing steps. It is an object of the present invention to provide a variable displacement pump that simplifies processing and assembly work, achieves cost reduction, and can achieve a smaller and lighter overall pump.

[0014]

SUMMARY OF THE INVENTION In order to meet such a demand, a variable displacement pump according to the present invention has a pump chamber provided between a vane and a rotor having the vane deflected to one side. A cam ring to be formed and a swing pin fitted around the cam ring and arranged along the axial direction on a part of the outer peripheral surface of the cam ring in the circumferential direction so as to be swingable so that the volume of the pump chamber fluctuates. A cam case to be supported; a front body and a rear body which are arranged at both ends in the axial direction of the cam case as an intermediate body and constitute a pump body; and a rotating shaft which rotates the rotor by being supported by these both bodies. Fluid pressure that is formed on both sides of the swing pin between the cam ring and the cam ring storage space in the cam case, and that changes according to the discharge flow rate from the pump chamber Thus the swinging the cam ring 1
And a second fluid pressure chamber, and biasing means provided in the cam case on the side of the second fluid pressure chamber to bias the cam ring in a direction in which the volume of the pump chamber is maximized. One end of the coil spring is held by a discharge-side connector screwed from the outer surface of the pump body or the cam case, and a discharge port on the pump discharge side is formed in the discharge-side connector.

According to the present invention, the assembly portion of the coil spring for urging the cam ring is also used as the discharge side connector, so that the installation of the coil spring and the assembly of the discharge side connector can be performed simultaneously.

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

The pump body is composed of both bodies formed by precision casting such as aluminum die casting and a cam case, and is formed by casting or drilling holes such as an internal passage and an internal space, and a valve hole. It is not limited to this. In addition, the shape of the rotating shaft is formed as straight as possible, and the rotating shaft is one piece using a double-layered bush made of aluminum and white metal for each body. It has a two-point support structure that is pivotally supported at each location, but is not limited thereto.

[0018]

1 to 12 show one embodiment of a variable displacement pump according to the present invention. In these drawings, in this embodiment, a hydraulic pressure source of a power steering device is used. The case of a vane type oil pump will be described.

As shown in FIGS. 1 and 4 to 9, a vane type variable displacement pump generally designated by the reference numeral 20 has a front body 21 and a rear body 22 which constitute a pump body, and a cam case 23 which serves as an intermediate body. And As shown in FIGS. 1, 4 and 5A and 5B, the front body 21 has a small-diameter portion 21a protruding at one end side, and penetrates a rotation shaft of a rotor 33 described later in the center. A shaft hole 21b to be arranged is formed.

FIGS. 1, 4 and 5 show the large diameter portion of the front body 21 joined to the cam case 23.
As shown in (a) and (b), a circular space 2 for accommodating a pressure plate 31 which is one of the pump components 30.
4 are formed, and an annular concave portion 24a is formed on the inner side of the circular space 24. This annular recess 24a
Is configured to form a discharge chamber 25 into which pressure oil on the pump discharge side is guided between the pressure chamber 31 and a pressure plate 31 described later.

As shown in FIGS. 1, 2, 3, 5, 6, and 7, the cam case 23 has a storage space 3 for storing a pump cartridge which is a pump component 30.
2 is formed at the center. This storage space 32 is shown in FIG.
A cam ring 34 formed in a substantially elliptical shape swelling in the left-right direction in FIG. 3 and fitted around the rotor 33 in a state where the rotor 33 having the vane 33a is shifted to one side.
Is swingably supported by a swing pin 35 arranged along the axial direction at a part of the circumferential direction, so that the volume of the pump chamber 36 is changed.

The cam ring 34 forms a pump chamber 36 between the inner peripheral surface and the outer peripheral surface of the rotor 33. The cam ring 34 is urged in a direction in which the volume of the pump chamber 36 is maximized by a compression coil spring 37 as an urging means provided on one side of the cam case 23.

The cam case 23 includes the cam ring 3
4 is a member corresponding to an adapter ring (1a in FIG. 16) for swingably holding the inside of the pump body. The rear side of the cam case 23 is assembled with the rear body 22 in contact therewith. The pump chamber 36 is formed between the rotor 33 and the cam ring 34 by the pressure plate 31 disposed in the storage space 24 on the body 21 side.

Reference numeral 40 denotes a drive shaft serving as a rotating shaft for driving the rotor 33, which is the rotor of the pump component 30, to rotate from the outside. The drive shaft 40 passes through the front body 21 and the rotor 33, and One end is fitted into a shaft hole 22 a provided in the rear body 22.
As shown in FIG. 1, the drive shaft 40 is configured to rotate integrally with the rotor 33 by serration coupling (or key coupling), and the shaft holes 21b and 22a of the front body 21 and the rear body 22 are formed.
Are rotatably supported by two-point support by bushings 41 and 42 as bearings provided on the shaft.

These bushes 41 and 42 are constituted by, for example, a double-layered wound bush made of aluminum and white metal, are disposed over a predetermined length in the axial direction, and rotate the drive shaft 40 with required strength. It is configured to be freely supported. In FIG. 1, reference numeral 43 denotes a bush 4 of the front body 21.
1 is an oil seal provided at the opening end of the shaft hole 21b on the small-diameter portion 21a side of the shaft hole 21b. Reference numeral 44 denotes a pulley provided on a pulley support ring 44a provided by press fitting or the like at the outer end of the drive shaft 40. The drive shaft 40 is rotatably driven by transmitting rotational power from an external drive source such as an electric motor to the drive shaft 40.

In this embodiment, the variable displacement pump 2
The pump body which comprises the front and rear bodies 21 and 22 formed by precision casting such as aluminum die casting and the cam case 23, and the shape of the drive shaft 40 serving as a rotating shaft is formed as straight as possible. Further, since the drive shaft 40 is supported by the bushes 41 and 42 on the respective bodies 21 and 22 one by one, there are the following advantages.

That is, in the conventional pump, a ball bearing is provided on the pulley 44 side to support the drive shaft 40, and a needle bearing or a bush is further provided in the body to support the three-point support.
On the other hand, in this embodiment, the two-point support by the bushes 41 and 42 as described above
By forming as straight as possible,
The outer diameter of the pump body can be made small, and the cost can be reduced by reducing the number of parts.

Further, in this embodiment, the axial length of the bush 41 in the front body 21 is increased, and the bush 41 is disposed closer to the pulley 44 in the small-diameter portion 21a. Even if it is thin, the strength against bending load can be increased, and the load capacity (PV value) as a pump can be improved. Further, as described above, by supporting the portion of the drive shaft 40 close to the rotor 33 with the bushes 41 and 42, it is possible to cope with an uneven load due to hydraulic pressure.

Further, as described above, the drive shaft 4
0 is formed in a substantially straight shape, so that the base end (33
The hole 31a for guiding high-pressure oil pressure to b) can be formed as a straight hole along the axial direction instead of the conventional oblique hole, so that the passage for introducing hydraulic oil can be enlarged and the plate 31 All straight holes can be easily processed. If this straight hole is formed by molding at the time of casting the plate 31, the cost can be reduced.

In the above configuration, the front body 2
1. The rear body 22 and the cam case 23 sandwiched between these bodies are laminated with the internal components incorporated therein, fastened by four fastening bolts 45 as fastening means, and integrally assembled. I have. Note that the cam case 2
The end face of the rear body 22 abutting on one side of the third component 3 functions as a side plate of the pump component 30. In FIG. 2, reference numeral 47 denotes the cam case 23 described above.
The pump chamber 36 and the cam ring 34 formed by the pump
O-rings for sealing the first and second fluid pressure chambers 38 and 39 for swinging, and a part thereof is formed in a shape having a bulging portion 47b which bypasses a relief valve 74 described later. Have been.

In the above configuration, in this embodiment, the front body 21 is divided into three bodies.
As one of means for positioning the rear body 22 and the cam case 23 as an intermediate body interposed therebetween by sandwiching the rear body 22, a swing pin 35 for swingably supporting a cam ring 34 in the cam case 23 is used. ing. According to such a configuration, since the existing component such as the swing pin 35 of the cam ring 34 is also used as the positioning component, it is not necessary to add an extra component, and the number of components of the pump is reduced. Moreover, the positioning in the surface direction and the circumferential direction at the joint surface between the cam case and the two bodies can be reliably performed. In other words, simply providing dedicated positioning means such as positioning pins at at least two places to perform positioning between the above-described members can be considered, but in this embodiment, at least one of them is provided with another function. The swing pin 35 is also used for positioning.

In this embodiment, at least one of bolts 45 for fastening the two bodies 21 and 22 and the cam case 23 is used as another positioning means.
By using the reamer bolt 45A screwed into B,
In order to reduce the number of components, this reamer bolt 4
5A can reliably receive an eccentric load due to the hydraulic pressure acting between the two bodies 21 and 22 and the cam case 23, so that reliability in assembling the pump 20 can be ensured.

In the above-described embodiment, one of the fastening bolts is a reamer bolt 45A as a positioning means together with the swing pin 35, but the present invention is not limited to this. For example, in FIG.
By providing the positioning pins 46 and 48 between the cam case 23 and the cam case 23, and between the cam case 23 and the rear body 22, the two bodies 21 and 22 and the cam case 23 can be easily positioned without using the reamer bolt 45A. It can also be assembled. At this time, if the insertion holes for the positioning pins 46 and 48 are formed by precision casting of the two bodies 21 and 22 and the cam case 23, the holes can be used.
It is also advantageous in terms of workability. Further, with such a configuration, the fastening bolt 45 can be freely tightened, which is advantageous in terms of workability during assembly.

Here, in FIG. 1 described above, at least two positioning pins 46 and 48 are used. However, the present invention is not limited to this, and one positioning pin is inserted and inserted into a required position to provide a positioning function. Is also good. In short, a swing pin for swingably supporting the cam ring 34 in the rotational direction of the cam case 23 which is sandwiched and fixed between the pair of front and rear bodies 21 and 22 and the positioning in the surface direction at each joint surface. 35 may be used.

Reference numeral 50 denotes a pump suction port provided in a part of the rear body 22. The port 50 is provided with a suction pipe 50a serving as a pump suction connector, and suction-side hydraulic oil flows from a tank. This hydraulic oil passes through a pump suction side passage 51 provided in the rear body 22, and opens into a pump suction side area 36 A of a pump chamber 36 formed between the cam ring 34 of the cam case 23 and the rotor 33. It is sucked into the pump chamber 36 through the opening 52, and is discharged from the pump discharge side opening 53 and the discharge side passage 54 on the pressure plate 31 side which opens to the pump discharge side area 36B under the action of the pump while the vane 33a moves. On the back side of the plate 31, a discharge chamber 25 which is a high-pressure chamber formed by the annular recess 24a of the front body 21.
(Pump discharge side pressure chamber).

In the embodiment shown in FIGS. 1 and 8 described above, machining of the pump suction port 50 and the pump suction side passage 51 in the rear body 22 are formed by passage holes formed by machining. However, it is not limited to this. For example, as shown in FIGS. 14A and 14B, when this rear body 22 is formed by a core casting hole when it is formed by casting, workability can be improved and cost can be reduced. It is the same as that of FIG. 1, and a specific description is omitted.

According to the present invention, the discharge chamber 25 is
(B), a hydraulic passage 56, a hydraulic passage 56,
12, the second fluid pressure chamber 39 through the discharge side passage 60 having the metering orifice 60a and the pump discharge side connector 5 as shown in FIG.
8 and is discharged from the pump discharge side port 59. In the above-described pump discharge side passage 60, the fluid passage hole 60 opening to the second fluid pressure chamber 39 is provided.
A variable metering orifice 60a capable of increasing or decreasing the opening area is formed by the side surface of the cam ring 34. Here, this variable metering orifice 60a
Is formed by opening and closing the small-diameter opening end of the passage hole 60 in the side wall portion with the movement displacement of the cam ring 34. When the orifice 60a is formed in an appropriate shape whose opening and closing amount is controlled in accordance with the magnitude of fluid pressure on the pump discharge side, the displacement of the cam ring 34 can be controlled to a desired state, and various flow characteristics can be obtained. Can be achieved.

In this embodiment, first and second fluid pressure chambers 38, 39 formed between the outer peripheral surface of the cam ring 34 and the cam ring storage space 32 in the cam case 23 so as to swing the cam ring 34. Control valve 5 for controlling the supply fluid pressure to the pump chamber 36 through passage holes 38a, 39a in accordance with the magnitude of the discharge flow rate of the pressure fluid from the pump chamber 36
5 is provided in a part of the cam case 23. And
As shown in FIG. 5B and FIG.
1. A high pressure side is formed by an oblique hole 56 opened from the inner discharge chamber 25 to the end surface serving as a joint surface with the cam case 23, and a hole 57 connecting the end surface of the cam case 23 and the valve hole 55a of the control valve 55. Is formed.

According to such a configuration, as shown in FIG. 5C, since a high-pressure portion such as the control valve 55 is provided in a part of the front body 21 in the related art, the front body 21 and the discharge chamber are provided. In forming the high pressure side hydraulic passage connecting to the front body 25, two passage holes 5 penetrating from two different places on the outer surface of the front body 21.
6a and 56b can be formed in combination, and the structure in which the open end is closed with a blind plug can be omitted, so that the number of processing steps can be greatly reduced, and blind plugs and the like can be omitted. Reduction can be achieved. Further, with such a structure, the above-mentioned fear of oil leakage at the blind plug portion can be eliminated, and reliability is improved.

In the above-described structure, the space for accommodating the conventional cam ring 34 and forming the first and second fluid pressure chambers 38 and 39 is formed by an adapter ring inserted into the internal space of the front body 21. On the other hand, the adapter ring is divided by the cam case 23 serving as an intermediate body, thereby simplifying the pump structure including the passage groove structure, and improving the workability of the passage holes and the like and the assemblability of the entire pump. Can be done.

Further, since the front body 21 and the rear body 22 are not fitted to each other by the spigot connection, the rear body 22 can be formed thick in the axial direction, and the pump suction port 50 can be connected to the rear side and the front side. Can be provided in either of them. In addition, with such a configuration, the rigidity of the rear body 22 can be improved, and the front body 21 and the rear body 2
It is not necessary to make the dimensional accuracy of strict 2 and processing becomes easy.

In FIGS. 2 and 3, reference numeral 35a denotes a seal member provided at a symmetric position of the swing pin 35 to define the pair of fluid pressure chambers 38 and 39. Passage holes 38a and 39a for guiding the fluid pressure before and after the orifice 60a are formed (see FIGS. 3, 6, and 7).
A passage hole 55b (see FIGS. 1, 6, and 8) reaching the first hole 51a is formed. Note that, in the above-described vane type variable displacement pump 20, configurations other than those described above are widely known in the related art, and a specific description thereof will be omitted.

In this embodiment, the cam ring 3
Control valve 55 for performing fluid pressure control for oscillating 4
Is used as a spool valve. As shown in FIGS. 1 and 3, a valve hole 55a forming the spool-type control valve 55 is orthogonal to the axial direction of the rotating shaft 40 so that one end of the cam case 23 is open to the outer surface. The valve component which forms the control valve 55 and is formed in the valve hole 55a. Also, as shown in FIGS. 3, 7 (a), (e) and 11, the plug 71 constituting the valve component is pulled out in the direction perpendicular to the valve hole 55a near the open end of the valve hole 55a. (In the axial direction of the rotating shaft 40), a through hole 72a penetrating the cam case 23 is provided.
, For example, a spring pin 72 is inserted. Then, both ends of the pin 72 are joined to both ends of the cam case 23 to close the opening end of the through hole 72a.
And at the end face of the rear body 22.

With such a configuration, the opening end of the valve hole 55a of the spool type control valve 55 is conventionally fixed by screwing a stopper plug after assembling the valve components, but a simple spring pin 72 is used. Since both ends of the spring pin 72 can be stopped and locked by the bodies 21 and 22 on both sides, screw processing at the assembly portion of the control valve 55 can be omitted and downsizing can be achieved. .

Further, no foreign matter such as dust and iron powder is generated by screwing and fixing the plug as in the prior art, and the use of the spring pin 72 can easily prevent rattling of valve components.

Also, in this embodiment, a relief valve provided between the pump discharge side and the pump suction side to relieve hydraulic oil to the pump suction side when the fluid pressure on the pump discharge side exceeds a certain pressure. 74 in FIGS. 8A and 8C.
As shown in FIG. 12, it is provided on the rear body 22. That is, the valve hole 75 constituting the relief valve 74 is formed by a blind hole having one end opened in the joint surface with the cam case 23 in the rear body 22, and the valve component 74 a incorporated in the valve hole 75 is The cam case 23 is locked at the joint surface (or a part of the front body 21).

Here, a part of the valve hole 75 for the relief valve 74 formed by the blind hole provided in the rear body 22 is provided in the passage 51 on the pump suction side in the passage hole 51 b and the shaft hole 2.
The passage 76 is connected through 2a. Reference numeral 76a denotes a blind plug for closing the opening end of a hole formed by machining the passage 76 from outside the rear body 22.

Further, a pressure detection switch 91 for detecting a state in which the fluid pressure on the pump discharge side has become equal to or higher than a predetermined pressure is provided in a part of the rear body 22 described above. The passage 92 connecting the low pressure side of the switch hole 91a incorporating the pressure detection switch 91 to the pump suction side is formed with the shaft hole 22a when the passage hole 51b is formed in the rear body 22 by machining as described above. It penetrates and is formed simultaneously to improve workability and reduce costs (see FIGS. 1 and 8).

According to the configuration described above, the relief valve 7
The stopper plug which is inserted into the opening end of the valve hole 75 of No. 4 is conventionally formed by screwing into the opening which is opened on the outer surface of the rear body 22. , Which can be configured by simple engagement with the cam case 23 or the front body 21, and the overall structure of the valve 74 can be simplified. Further, it is possible to prevent the generation of foreign matter such as dust and iron powder due to the screw fitting of the stopper plug as in the related art, and it is possible to lock the movement of the plug in the axial direction at a required position.

The relief valve 74 as described above
By forming the passages 76 and 92 connecting the low pressure side of the pressure detection switch 91 to the pump suction side by simple machining in the rear body 22, the number of machining steps can be reduced and cost can be reduced. Here, the specific structure of the pressure detection switch 91 is omitted.
It is advisable to employ an appropriate pressure detection switch structure such as that of 540145.

In the cam case 23, the swing pin 3
First and second swinging cam rings 34 on both sides of the cam ring 34 by a fluid pressure introduced in accordance with the magnitude of the discharge flow rate discharged from the pump chamber 36 on both sides of the position 5 and the position (seal member 35a) opposed thereto. Fluid pressure chambers 38 and 39 are formed. In this embodiment, of these fluid pressure chambers, the cam ring 3 provided on the second fluid pressure chamber 39 side is provided.
A hole 94 formed from the outer surface of the pump body (cam case 23) is provided with a coil spring 37 using the coil spring 4 as an urging means for applying an urging force in a direction in which the volume of the pump chamber 36 is maximized.
Provided within. Further, a discharge-side connector 58 that forms a discharge port (discharge port 59) for pressure oil on the pump discharge side is provided in the hole 94.

According to such a configuration, the cam ring 34
Since the assembly part of the coil spring 37 for urging the pressure and the discharge-side connector 58 can be used in combination, the number of processing steps can be reduced as compared with the conventional case, the cost can be reduced, and the size of the entire pump can be reduced. It is also possible to achieve cost reduction by reducing the number of components.

Further, in this embodiment, the pressure plate 31 is provided inside the front body 21 at a position in contact with the cam case 23 side and forms a discharge chamber 25 for guiding the pump discharge side pressure oil to the back side thereof. Pump chamber 36 between the back and front body 21
As shown in FIGS. 1 and 4, a low-pressure chamber 80 for guiding a low-pressure hydraulic pressure is provided by a recess at a position facing the pump suction side region 36A. Here, reference numeral 81 in the figure denotes an O-ring having a substantially arcuate shape for sealing the low-pressure chamber 80 from the discharge chamber 25 side.

According to such a structure, the hydraulic pressure on both sides of the pressure plate 31 in contact with the pump chamber 36 formed by the rotor 33 and the cam ring 34 can be balanced, and the deformation of the plate 31 can be prevented. Galling and seizure of the plate 31 and the rotor 33 and the cam ring 34 of the rear body 22 can be prevented.

By appropriately selecting the ratio of the area of the region formed by the recessed portion serving as the low-pressure hydraulic low-pressure chamber 80, the pressure plate 31 can be appropriately deformed. The degree of pressure contact with the cam ring 34 or the like constituting the pump chamber can be adjusted by skillfully utilizing this deformed state, and for example, the amount of internal leakage at high pressure can be reduced. 1 and 4
Reference numeral 82 denotes a return passage for returning hydraulic oil leaking to the oil seal 43 to the pump suction side. Also,
In FIGS. 1 and 10, 83 and 83a denote the low-pressure section 80 described above.
There are a passage hole connected to the pump suction side for maintaining a low pressure state and a concave groove serving as a suction side opening. Further, in the figure, 31b is a shaft hole of the pressure plate 31, and 31c is the vane 33a.
Hole 31 for introducing pump discharge pressure to the base end of
The grooves are connected via a.

Further, in this embodiment, in the above-described pressure plate 31, the pressure plate 31 shown in FIGS.
As shown in (b), the pump suction side area 3 of the pump chamber 36
6A, a bridging portion 54a is provided in at least one of the pump suction side opening 83a and the pump discharge side opening 53 (here, the pump discharge side opening 54) formed in the pressure plate 31 corresponding to the pump discharge side region 36B. ing. These bridging portions 54a are provided at positions separated from the end face on the pump chamber 36 side in the concave groove 83a serving as the pump suction side opening 52 and the concave groove 53a of the pump discharge side opening 53.

In FIGS. 10 (a) and 10 (b), the arc-shaped through hole is provided with a through passage hole (reference numeral 54 in the figure) in the arcuate concave groove 53a serving as the pump discharge side opening 53. Part), but is not limited to this.
It may be configured as shown in FIG. That is, in FIG. 10C, the pump discharge side opening 54 (or the pump suction side opening 52) is formed by a plurality of circular holes 54, so that a bridge portion 54a is formed between the circular holes 54.

According to such a configuration, the pump suction side opening 52 formed in the pressure plate 31 in a substantially arc shape corresponding to the pump suction side area 36A and the pump discharge side area 36B of the pump chamber 36, Discharge side opening 5
The bridge 54 a prevents the rigidity of the pressure plate 31 from decreasing due to the presence of the pressure plate 3, and the rigidity can be ensured.

The number and position of the bridging portions 54a may be arbitrarily selected depending on the rigidity of the pressure plate 31. Further, the pump suction side opening 52 and the pump discharge side opening 53 having such a bridging portion 54a can be formed to have an arbitrary shape by a mold (or a mold). In particular, when the pressure plate 31 is formed by a combination of the circular holes 54, it can be formed as a simple die-cut hole (cast-hole portion) when forming the pressure plate 31, which is advantageous in cost.

The present invention is not limited to the structure of the above-described embodiment, and it is possible to freely change and change the shape, structure, and the like of each part, and various modifications are conceivable. For example, in the above-described embodiment, an example in which the pump suction port 50 is formed in the rear body 22 has been described. However, the present invention is not limited to this, and the pump suction port 50 is provided on the front body 21 side as shown in FIG. The control valve 55 may be connected to the suction-side passage 51 provided in the rear body 22 through a low-pressure portion of the valve hole 55a. Here, 50b is a passage hole for guiding the suction port 50 of the front body 21 to the cam case 23 side.

Here, in FIG. 13 described above, a passage 76 for connecting a part of a valve hole 75 for a relief valve 74 formed by a blind hole provided in the rear body 22 to the pump suction side is provided.
The rear body 22 is formed by a core casting hole when the rear body 22 is formed by casting. In this way, FIG. 13 and FIG.
(A), (b), (c), the rear body 22
There is an advantage in that the machining of the passage hole and the like in the above is minimized, which is advantageous in processing, and that the blind plug 76a is not required as compared with FIG. Further, as is clear from the comparison between FIG. 12 and FIG. 14, the degree of freedom of the passage structure is increased.

Further, a low pressure side of a switch hole 91a in which a pressure detection switch 91 provided in a part of the rear body 22 to detect a state in which the fluid pressure on the pump discharge side is equal to or higher than a predetermined pressure is set to the pump suction side. If the passage 92 connected to the hole is formed by a core casting hole when the rear body 22 is formed by casting in the same manner as described above, the workability is excellent and the cost can be reduced.

As described above, the passages 76 and 92 connecting the low pressure side of the relief valve 74 and the pressure detection switch 91 to the pump suction side are formed simultaneously with the core formed in the rear body 22 formed by casting. The number of processing steps can be reduced, and the cost can be reduced.

In the above-described embodiment, the pump discharge port 59 having the pump discharge port 59 is replaced with the pump discharge port 59 as shown in FIG.
Although a case where a shape opened in a direction orthogonal to the axial direction of the line 8 is used has been described, the present invention is not limited to this, and FIG.
As shown in FIG. 5, a pump 58 having a simple shape in which a pump discharge port 59 is opened in the axial direction of the connector 58 may be used.

Further, the vane type variable displacement pump 20 having the above-described configuration is not limited to the structure of the above-described embodiment, but may be various types other than the power steering device described in the above-described embodiment. You may apply to an apparatus and an apparatus.

[0066]

As described above, according to the variable displacement pump according to the present invention, since the built-in portion of the coil spring for biasing the cam ring can be used as the discharge side connector, the processing can be performed as compared with the conventional one. Not only the man-hours can be reduced and the cost can be reduced, but also the entire pump can be reduced in size and the cost can be reduced by reducing the number of components.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a variable displacement pump according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the vicinity of a pump chamber of the variable displacement pump taken along a line II-II in FIG.

FIG. 3 relates to a variable displacement pump according to the present invention;
FIG. 3 is a cross-sectional view of the vicinity of a pump chamber of the variable displacement pump, taken along line III-III of FIG.

FIG. 4 is a side view of the front side of the variable displacement pump taken along the line IV-IV in FIG. 1;

5A is a side view of the variable displacement pump shown in FIG. 1 as viewed from the front body side, and FIG.
FIG. 4C is a sectional view taken along line V, and FIG. 5C is a view for explaining a conventional example corresponding to FIG.

6A is a front view of a cam case, and FIG. 6B is a sectional view taken along line VI-VI of the variable displacement pump shown in FIG.

7A is a sectional view of a main part of a cam case, and FIGS. 7B to 7E are BB line, CC line, and DD line in FIG. EE line sectional view.

8 (a) is a side view of the variable displacement pump shown in FIG. 1, as viewed from the joint surface of the rear body with the cam case;
(B) is a sectional view taken along line VIIIb-VIIIb, and (c) is a sectional view taken along line VIIIc-VIIIc of (a).

FIG. 9 is a side view of the variable displacement pump of FIG. 1 on the rear body side.

10 (a) shows the variable displacement pump shown in FIG.
FIG. 7 is a side view of the pressure plate on the pump chamber side, FIG. 7B is a side sectional view thereof, and FIG. 7C is a view showing a modified example of FIG.

11 is a sectional view taken along line XI-XI in FIG.

FIG. 12 is a sectional view taken along line XII-XII in FIG. 9 and an enlarged sectional view of a main part thereof.

FIG. 13 is a side sectional view showing a modified example of the variable displacement pump according to the present invention.

14A and 14B show another embodiment of the variable displacement pump according to the present invention, wherein FIG. 14A is a side view of the rear body as viewed from the joint surface with the cam case, FIG. 14B is a side sectional view thereof, and FIG. FIG. 4 is a sectional view of a main part of a relief valve assembly part.

FIG. 15 is a side sectional view showing still another embodiment of the variable displacement pump according to the present invention.

FIG. 16 is an explanatory diagram for explaining a main structure of a conventional variable displacement pump.

[Explanation of symbols]

20: Vane type variable displacement pump, 21: Front body (pump body), 21a: Small diameter portion, 21b
... Shaft hole, 22 ... Rear body (pump body), 23 ... Cam case (intermediate body), 24 ... Circular space, 24a ... Circular recess, 25 ... Discharge chamber (pump discharge side pressure chamber), 30 ...
Pump components, 31 ... pressure plate, 31a ...
Hole, 31b: shaft hole, 32: storage space, 33: rotor,
33a: vane, 34: cam ring, 35: swing pin,
36 (36A, 36B) ... pump chamber (pump suction side area, pump discharge side area), 37 ... coil spring (biasing means), 38, 39 ... first and second fluid pressure chambers, 40 ... drive shaft ( Rotating shaft), 41, 42 ... bush, 43
... oil seal, 44 ... pulley, 45 ... fastening bolt (fastening means), 45A ... reamer bolt, 45B ... reamer hole,
46: positioning pin, 47: O-ring, 50: pump suction port, 50a: pump suction side connector, 51: pump suction side passage, 51a, 51b: passage, 52: pump suction side opening, 53: pump discharge side opening, 53a: concave groove, 5
4 ... Discharge side passage, 54a ... Bridge, 55 ... Control valve,
55a ... valve hole, 55b ... passage, 56, 57 ... hydraulic passage, 58 ... pump discharge side connector, 59 ... pump discharge side port, 60 ... discharge side passage (fluid passage hole), 60a ... metering orifice, 71 ... plug , 72: spring pin (pin), 74: relief valve, 74a: valve component, 75: valve hole (blind hole), 76: passage, 8
0: low pressure chamber, 81: O-ring, 83: passage hole, 83a ...
Concave groove, 91: pressure detection switch, 91a: switch hole,
92 ... passage.

Claims (2)

[Claims] 1. A cam ring which forms a pump chamber between a rotor having a vane and a rotor which is deflected to one side, and a cam ring which is fitted around the cam ring and has a circumferential direction on an outer peripheral surface of the cam ring. A cam case that swingably supports the pump chamber such that the volume of the pump chamber fluctuates around a swing pin disposed along the axial direction in the portion, and a pump body that is arranged at both axial ends of the cam case. A front body and a rear body, a rotating shaft rotatably supported by the two bodies to rotate the rotor, and formed on both sides of the swing pin between the cam ring and a cam ring storage space in a cam case. A first and a second fluid pressure chamber for oscillating a cam ring by a fluid pressure that varies according to a discharge flow rate from a pump chamber; and the cam case. Biasing means provided on the second fluid pressure chamber side for biasing the cam ring in a direction in which the volume of the pump chamber is maximized. One end of a coil spring constituting the biasing means is connected to the pump body. A variable displacement pump characterized in that a discharge side connector screwed from an outer surface holds the discharge side connector and a discharge port on a pump discharge side is formed in the discharge side connector. 2. The variable displacement pump according to claim 1, wherein the discharge side connector is provided in a cam case sandwiched and held between a front body and a rear body.