JP2002098068A - Pumping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the flow cut-off characteristic of an operating fluid when relieved in a pumping device using a flow control valve for discharging the operating fluid through a spool valve element. SOLUTION: A pressure chamber 18 into which the operating fluid from a vane pump part 20 is discharged, is communicated with an intake port 24 through a flow control valve 40 and a by-pass passage 14. A guide pipe 30 formed with a discharge passage 33 and provided with an orifice 32 is coaxially fixed to a valve hole 41 formed at the rear part of a housing 10. The spool valve element 42 of stepped cylinder shape coaxially formed with a small diameter part 42a at the tip part is slidably fitted to the valve hole and the guide pipe. An annular chamber 44 and the by-pass passage are communicated with each other by a line 48 provided with a pilot relief valve 49, and if the operating pressure in the discharge passage exceeds relief pressure and is relieved through a damping hole 30a and the line, a spool valve element retreats, and the operating fluid in the pressure chamber is relieved to the by-pass passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small and lightweight pump device suitable for use in a vehicle power steering device or the like.

[0002]

2. Description of the Related Art A power steering device for a vehicle is small and lightweight,
Since advantages such as low pulsation and low noise can be obtained, a balanced vane pump having suction and discharge ports arranged symmetrically with respect to the rotation axis of the rotor is often used. In addition, in a pump device for a power steering device, a surplus flow rate from a discharge port is used to supply a constant flow of hydraulic oil to the power steering device irrespective of fluctuations in the rotation speed of a pump driven by a vehicle engine. A flow control valve is provided in a bypass passage for returning the pressure to the suction port side. More specifically, the spool valve body of the flow control valve is moved according to the pressure difference before and after the metering orifice provided in the discharge passage communicating the pressure chamber formed on the discharge port side and the power steering device, By changing the opening of the flow control valve, the excess flow from the discharge port is returned to the suction port.

[0003]

However, the metering orifice used for this purpose is usually provided separately from the spool valve body. Therefore, in order to operate the flow control valve, it is necessary to pass the metering orifice after passing through the metering orifice. It is necessary to form a pass hole in the housing for guiding the above pressure to the rear chamber of the spool valve body, which increases the processing labor.

[0004] Further, in a normal flow control valve, a relief function is provided to the discharge passage so that the operating pressure does not exceed a predetermined value.
As disclosed in Japanese Patent Publication No. 315322, there is a spool valve body for flow control that incorporates a load pressure application spool (relief pilot valve) so that the spool valve body functions as a main valve at the time of relief. . This structure eliminates the need to form a relief circuit pass hole in the housing, etc., and makes the spool valve element play the role of the main valve at the time of relief, so the relief circuit is compact, but there is a relief inside the spool valve element. It is necessary to incorporate a pilot valve, which restricts the reduction of the outer diameter and length of the spool valve body, which causes a problem that it is difficult to reduce the size and weight of the flow rate control valve and, consequently, the entire pump device using the same. .

On the other hand, the spool valve element 42 is provided with a metering orifice instead of the relief pilot valve so that hydraulic oil supplied to the power steering device is drawn out through the spool valve element (for example, a special pump device). Opening 2
According to this, there is no need to form a passage hole in the housing for guiding the pressure after passing through the metering orifice to the rear chamber of the spool valve body, so that the size and weight of the flow control valve section are reduced. Is possible. However, in this structure, it is not possible to increase the relief capacity by causing the spool valve body to function as a main valve at the time of relief. Therefore, unless a large separate relief valve is used, the flow rate of the hydraulic oil discharged from the pump device is cut. The off characteristics could not be improved. An object of the present invention is to solve such problems in the in-line type flow control valve.

[0006]

According to a first aspect of the present invention, there is provided a pump device having a vane pump portion provided in a housing and having a rotor rotatably supported around an axis in the front-rear direction. A pressure chamber formed between the rear portion and the discharge port of the vane pump portion is opened and communicated with the discharge port through an orifice and a discharge passage, and a pressure chamber formed in the housing and connected to the suction port side of the vane pump portion. A bypass passage communicating with the
In a pump device provided with a flow control valve provided between a pressure chamber and a bypass passage to adjust a reflux amount from the pressure chamber to the suction port side, the flow control valve has a small-diameter portion coaxially formed at a distal end thereof. A stepped cylinder formed in the rear part of the housing to open and close the bypass passage in the valve hole, slides into the valve hole with one end opened to the pressure chamber and one end of the bypass passage opened to the side so as to open and close the bypass passage in the valve hole. It consists of a spool valve body that is freely fitted and moves according to the pressure difference before and after the orifice to change the opening of the flow control valve.The housing has an inner hole that forms a discharge passage at the rear. A tubular guide tube protruding coaxially into the valve hole and slidably fitted in the small diameter portion of the spool valve body is fixed, and an orifice is formed in a part of the guide tube, and the orifice is formed in the guide tube. Form between the guide tube, the rear of the housing and the spool valve The formed annular chamber is formed with a damping hole communicating with a discharge passage located on the rear side of the orifice, and a pipe communicating with the annular chamber and the bypass passage is provided in the discharge passage when the pressure in the annular chamber becomes a predetermined value or more. And a relief pilot valve for discharging the working fluid to the bypass passage through the damping hole.

According to a second aspect of the present invention, in the first aspect of the present invention, a rear side plate having a discharge port is abutted on the rear side of the vane pump portion, and the pressure chamber is in contact with the rear side surface of the rear side plate. It is characterized in that it is formed between the opposing rear portion of the housing.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the spool valve body is urged forward by a spring so that the distal end of the small-diameter portion abuts the rear side surface of the rear side plate. The spool is stopped, and a communication portion is formed at the distal end of the small-diameter portion of the spool valve body to communicate the inside and outside of the small-diameter portion.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the valve hole of the flow control valve is formed coaxially with the rotor of the vane pump portion. It is.

According to a fifth aspect of the present invention, in the second or fourth aspect, the rear side plate is coaxial with the valve hole and can be inserted into the small-diameter portion of the spool valve body and extends along the longitudinal direction. The adjustment rod whose diameter changes is fixed, an annular projection is formed at the tip of the inner surface of the small diameter portion of the spool valve body, and a variable orifice instead of the above-mentioned orifice is formed between the annular projection and the adjustment rod. It is a feature.

According to a sixth aspect of the present invention, in the third or fourth aspect of the present invention, the rear side plate can be inserted into the small diameter portion of the spool valve body coaxially with the valve hole and along the longitudinal direction. An adjusting rod whose diameter changes is fixed, an annular projection is formed at the tip of the inner surface of the small diameter portion of the spool valve body, and the communication portion is formed at a small diameter portion closer to the tip side than the annular projection. A variable orifice instead of the above-mentioned orifice is formed between the control rod and the adjusting rod.

According to a seventh aspect of the present invention, in the fifth or sixth aspect of the present invention, the adjusting rod has a small diameter portion on the root side fixed to the rear side plate and is always inserted into the small diameter portion of the spool valve body. The large diameter portion is provided on the leading end side.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment will be described with reference to FIGS. The pump device of this embodiment is
A housing 10, a vane pump unit 20 provided in the housing 10 and driven to rotate by a pump shaft 27;
A flow control valve 40 for adjusting the amount of recirculation from the discharge port 25 to the suction port 24 of the vane pump section 20 and a pressure chamber 18 from which hydraulic oil is discharged from the vane pump section 20 and a discharge port 34 of a pump device. The orifice 32 is a main component.

The housing 10 is a front housing 10
and a rear housing 10b which is screwed and fixed to the rear side and covers the front side. A pump shaft 27 is rotatably supported on the front part of the front housing 10a via a pair of ball bearings 28 around a longitudinal axis. Have been. A stepped cylindrical inner surface 10c is formed coaxially with the pump shaft 27 on the front housing 10a except for the front portion.
An annular fluid flow space 15 is formed eccentrically (see FIG. 2) at the axially intermediate portion of (a). Both of the disk-shaped front side plate 11 and the rear side plate 12 are fitted to the front and rear portions of the inner surface 10c so as to be slidable in the front-rear direction. 20 are provided. Between the front housing 10a and the rear housing 10b, between the inner surface 10c of the front housing 10a and the cylindrical portion 10b1 formed on the front surface of the rear housing 10b fitted thereto, and between the inner surface 10c of the front housing 10a and the rear side plate 12. Between the O-rings 19a, 19b
And 19c are sealed in a liquid-tight manner.

The vane pump section 20 includes a cam ring 21 supported by a front housing 10a by a positioning pin 26, a rotor 22 coaxially spline-coupled to an inner end of a pump shaft 27, and a rotor 22 as will be described later. A vane 23 which is slidably supported by the plurality of radial slits and is always in contact with a substantially elliptical cam surface formed on the inner periphery of the cam ring 21. It is located between the plates 12. The rear side plate 12 is a rear housing 10b.
Is elastically pressed against the rear surface of the cam ring 21 of the vane pump section 20 by a corrugated washer 35 interposed between
As a result, the cam ring 21 is attached to both side plates 11, 1
2 elastically sandwiched therebetween. The cam ring 21 is positioned within the width of the fluid flow space 15 in the front-rear direction, and the cam ring 21 and the side plates 11 and 12 are separated by a pair of positioning pins 26 extending in the axial direction.
Is positioned in the circumferential direction.

A pair of suction ports 24 for sucking hydraulic oil in the fluid flow space 15 into the vane pump section 20 are formed on both side plates 11 and 12 symmetrically with respect to the rotation axis of the rotor 22. , And rear side plate 1
2, a pair of discharge ports 25 for discharging the hydraulic oil from the vane pump section 20 are formed symmetrically with respect to the rotation axis of the rotor 22 in a phase direction approximately 90 degrees away from the suction port 24. (See FIG. 2). Each discharge port 25 is open to a pressure chamber 18 formed between the rear housing 10b and the rear side plate 12.

In the rear housing 10b, a valve hole 41 of a flow control valve 40 having a front end opened to the pressure chamber 18 coaxially with the rotation axis of the rotor 22, and a discharge port 34 opened in the rear surface of the rear housing 10b. And round holes 10b2 located between them are formed continuously in series. In the housing 10, a bypass passage 14 that communicates a side surface of an intermediate portion of the valve hole 41 with the fluid circulation space 15 is formed along a plane substantially including a rotation axis of the rotor 22 and connecting the two suction ports 24. It is formed. This bypass passage 14
Are first orthogonally formed in the rear housing 10b.
And a second passage 14a, 14b, a corner guide 14d fitted in a liquid-tight manner to the first passage 14a to smoothly connect the two passages 14a, 14b, and a front housing 10a.
It is formed by a third passage 14c formed therein.
A suction passage 13 to which hydraulic oil is supplied from a reservoir (not shown) is connected to a position 14e on the pressure chamber 18 side of the first passage 14a which is close to the valve hole 41.

A round hole 10b2 formed in the rear housing 10b between the valve hole 41 and the discharge port 34 has a valve hole 41.
A rear portion of the guide tube 30 that protrudes coaxially into the inside is fitted and fixed. An inner hole of the guide tube 30 forms a discharge passage 33 that guides hydraulic oil in the pressure chamber 18 to a discharge port 34, and an orifice 32 is formed at a closed end thereof. The orifice 32 may be provided at an intermediate portion of the guide tube 30. Further, in this embodiment, at the rear end of the guide tube 30, a sheet union 31 for piping for guiding hydraulic oil to a supply destination is integrally formed, but the guide tube 30 and the sheet union 31 are formed.
May be formed separately from each other, and separately press-fitted into the round hole 10b2 from both sides.

Spool valve body 4 constituting flow control valve 40
Reference numeral 2 denotes a stepped cylindrical shape having a small diameter portion 42a formed coaxially at the distal end thereof, and the outer peripheral surface thereof is slidably fitted in the valve hole 41 to open and close the bypass passage 14. The inner peripheral surface of the small diameter portion 42a is slidably fitted to the outer peripheral surface of the guide tube 30. An annular chamber 44 formed between the rear housing 10b, the guide tube 30 and the spool valve body 42 is communicated with a discharge passage 33 provided behind the orifice 32 by a damping hole 30a formed in the guide tube 30. . The spool valve element 42 is elastically urged toward the pressure chamber 18 by a spring 43 provided in the annular chamber 44 and interposed between the spool valve element 42 and the rear end face of the valve hole 41. The front end of the rear side plate 42 abuts on the rear side surface of the rear side plate 12 and is stopped, and the bypass passage 14 is closed. A communication portion 45 that communicates the inside and outside of the small diameter portion 42a is formed at the tip of the small diameter portion 42a of the spool valve element 42. The communication part 45 in this embodiment is a plurality of slit-shaped notches, but may be a round hole.

As shown in FIG. 1, a pipe 48 communicating with the annular chamber 44 and the bypass passage 14 has a damping hole for the working fluid in the discharge passage 33 if the pressure in the annular chamber 44 exceeds a predetermined relief pressure. A relief pilot valve 49 that discharges to the bypass passage 14 through 30a is provided.
In FIG. 1, the pipeline 48 and the relief pilot valve 49 are schematically shown, but the pipeline 48 is
0b, and the casing of the relief pilot valve 49 is also formed by the rear housing 10b.

In the first embodiment, the pump shaft 27
When the rotation of the engine of the vehicle is transmitted to the pump shaft 27 via a drive belt hung on a V-pulley 29 fixed to the tip of the vane pump and the rotor 22 of the vane pump 20 is rotated, the reservoir (shown in FIG. Hydraulic oil in the omission) is sucked into the vane pump section 20 through the bypass passage 14, the fluid circulation space 15, and the pair of suction ports 24,
The hydraulic oil is discharged from the pair of discharge ports 25 into the pressure chamber 18 and flows through the orifice 32. Due to this flow, a pressure difference occurs before and after the orifice 32, the front pressure is applied to the front surface of the spool valve body 42 facing the pressure chamber 18 side, and the rear pressure is transmitted from the damping hole 30a to the annular chamber 44.
And enters the rear surface of the spool valve element 42. When the rotational speed of the pump shaft 27 is low, the pressure difference is small, so that the spool valve element 42 does not move against the spring 43, the flow control valve 40 remains closed, and the hydraulic oil Is supplied from the pressure chamber 18 through the communication part 45, the orifice 32 and the discharge passage 33 to the power steering device or the like from the discharge port 34. At this stage, the discharge flow rate from the discharge port 34 increases in proportion to the increase in the rotation speed of the pump shaft 27.

As the rotational speed of the pump shaft 27 increases and the flow rate of hydraulic oil supplied from the discharge port 34 through the orifice 32 increases, the pressure difference between the front and rear of the orifice 32 increases. When the flow rate reaches a predetermined value, the pressure difference between before and after the orifice 32 reaches the predetermined value. When the flow rate exceeds this value, the spool valve element 42 retreats against the spring 43, the flow control valve 40 opens, and the pressure chamber 18 Hydraulic fluid flows into the bypass passage 14
Then, the fluid returns to the suction port 24 side of the vane pump section 20 through the fluid circulation space 15. At the time of this recirculation, the bypass flow that vigorously squirts from the pressure chamber 18 into the bypass passage 14 involves the working oil flowing from the suction passage 13 connected to the bypass passage 14 at the position 14 e close to the valve hole 41. Thereafter, the dynamic pressure is converted into static pressure in the bypass passage 14, the pressure increases, and the fluid is supercharged into the fluid circulation space 15.

Thereafter, if the rotation speed of the pump shaft 27 increases and the discharge flow rate of the hydraulic oil from the discharge port 25 increases, the pressure difference between the orifice 32 and the pressure increases.
The flow control valve 40 is automatically adjusted so that the opening increases by that much to increase the amount of recirculation, and the discharge flow rate of the hydraulic oil from the discharge port 34 is kept almost constant.

In the above-described operating state, normally, there is no flow of the hydraulic oil through the pipe line 48, and therefore no flow through the damping hole 30a, so that the respective pressures in the discharge passage 33 and the annular chamber 44 are the same. . However, the operating pressure of the discharge port 34 is reduced by the relief pilot valve 49 due to some cause (for example, a large steering until the stopper hits the stopper in a stopped state).
When the pressure exceeds the relief pressure Pr, a flow of hydraulic oil is generated in the pipeline 48 provided with the relief pilot valve 49. The flow of the hydraulic oil through the damping hole 30a causes the annular chamber 4
4 is lower than the pressure in the discharge passage 33,
The spool valve element 42 is retracted against the spring 43,
The hydraulic oil in the pressure chamber 18 is relieved to the bypass passage 14. That is, the flow control valve 40 having a function of returning the hydraulic oil from the vane pump section 20 to the suction port 24.
Spool valve element 42 also serves as a main valve at the time of relief. As a result, the relief capacity when the hydraulic oil in the pressure chamber 18 is relieved toward the bypass passage 14 becomes sufficiently large, so that a relief pressure characteristic with a small pressure override as shown in FIG. 3 is obtained, and the relief oil is discharged from the pump device. The flow cutoff characteristic of the hydraulic oil can be improved.

According to the first embodiment, the small-diameter portion 42a of the spool valve body 42 is slidably fitted into the tubular guide tube 30 having the orifice 32 formed therein.
Hydraulic oil is drawn out through the pressure chamber 0, the pressure after passing through the orifice 32 is introduced into the annular chamber 44 on the rear side of the spool valve body 42 through the damping hole 30a formed in the guide pipe 30, and the flow control valve 40 is operated to operate The amount of recirculation from the suction port to the suction port 24 is adjusted, so that it is not necessary to form a passage hole in the housing for guiding the pressure after passing through the orifice to the rear chamber of the spool valve body. The weight can be reduced.

Further, according to the first embodiment, the spool valve element 42 is stopped when the distal end of the small diameter portion 42a abuts on the rear side surface of the rear side plate 12, so that the positioning of the spool valve element 42 is performed. Can be performed accurately and easily.
However, the present invention is not limited to this, and may be implemented such that the spool valve body 42 is stopped by contacting a step portion or the like formed in the valve hole 41.

Further, in the first embodiment, the valve hole 41 of the flow control valve 40 is connected to the rotor 22 of the vane pump section 20.
Since the rear housing 10b is formed coaxially, the processing of the rear housing 10b is facilitated, and the outer diameter of the pump device does not increase. As in the first embodiment, the vane pump 20
And discharge ports 24, 25 commonly used as
If the bypass passage 14 is formed along a plane including the rotation axis of the rotor 22 and substantially perpendicular to the line connecting the two suction ports 24, the flow control can be performed. Since the flow from the valve 40 to each suction port 24 and the flow from each discharge port 25 to the flow control valve are performed evenly, the advantages of low pulsation and low noise of the balanced vane pump can be maximized. Can be.

Next, a second embodiment shown in FIGS. 4 and 5 will be described. The first embodiment is characterized in that the orifice provided between the pressure chamber 18 from which the hydraulic oil is discharged from the vane pump section 20 and the discharge port 34 of the pump device is a variable orifice 32A having a variable opening area. Since this embodiment is only different from the embodiment, this difference will be mainly described, and other description will be omitted.

In the rear side plate 12 of the second embodiment, an adjustment rod 47 which can be inserted into the small diameter portion 42a of the spool valve body 42 coaxially with the valve hole 41 of the flow control valve 40. It protrudes into the pressure chamber 18 and is fixed. The adjusting rod 47 has a small-diameter portion 47a on the root side fixed to the rear side plate 12, a large-diameter portion 47b on the tip side which is the spool valve body 42 side, and an intermediate portion thereof having a tapered shape connecting the both. I have. The guide tube 30 has a simple cylindrical shape and has no orifice.

The large-diameter portion 47b of the adjusting rod 47 is always inserted into the small-diameter portion 42a of the spool valve body 42, and the distal end of the small-diameter portion 42a contacts the rear side surface of the rear side plate 12. When the flow control valve 40 is in a non-operating state, an annular protrusion 46 is formed at the tip of the inner surface of the small diameter portion 42a of the spool valve body 42 corresponding to the small diameter portion 47a of the adjustment rod 47. The inner diameter of the annular projection 46 is slightly larger than the outer diameter of the large diameter portion 47b of the adjustment rod 47, and a variable orifice 32A is formed between the annular projection 46 and the adjustment rod 47. Small diameter portion 42a of spool valve element 42
A communication portion 45 that communicates between the inside and the outside is formed in a small-diameter portion 42a that is closer to the distal end than the annular protrusion 46. Discharge passage 3
As the discharge flow rate Q of the operating oil passing through the spool 3 increases, the spool valve body 42 retreats, but the opening area of the variable orifice 32A is constant and large in a range where the annular projection 46 is located at a position corresponding to the small diameter portion 47a. The opening area of the variable orifice 32A gradually decreases as the spool valve element 42 retreats in a range where 46 is located at a position corresponding to the large diameter portion 47b.

As in the case of the first embodiment, the second
Also in the embodiment, when the rotation speed N of the pump shaft 27 is low, the flow control valve 40 remains closed, and the discharge port 3
4 increases in proportion to the increase in the rotation speed N of the pump shaft 27 (see line a in FIG. 5). Pump shaft 2
7, the discharge flow rate Q exceeds a predetermined value, the spool valve body 42 retreats against the spring 43, the flow control valve 40 opens, and the annular projection 46 is positioned at the position corresponding to the small diameter portion 47a. , The opening area of the variable orifice 32A is constant and large, so that the discharge flow rate Q of the hydraulic oil from the discharge port 34 is maintained at a substantially large value (see the line b in FIG. 5). In the range where the rotation speed N of the pump shaft 27 further increases, the spool valve element 42 further retreats, and the annular projection 46 corresponds to the tapered portion between the small diameter portion 47a and the large diameter portion 47b, the opening area of the variable orifice 32A is Since the discharge flow rate Q decreases gradually as the rotation speed N increases (see line c in FIG. 5), the rotation speed N further increases, the spool valve element 42 further retreats, and the annular projection 46 becomes larger in diameter. In the range corresponding to 47b, the opening area of the variable orifice 32A is constant and small, so that the discharge flow rate Q is almost constant and small (see line d in FIG. 5). That is, a pump device having characteristics suitable for a power steering device for a vehicle, in which the discharge flow rate Q from the discharge port 34 decreases as the rotation speed N of the pump shaft 27 increases, is obtained.

At any stage of the above-described operation, if the operating pressure of the discharge port 34 exceeds the relief pressure Pr of the relief pilot valve 49 for some reason, as in the case of the first embodiment, the relief pilot valve A flow of hydraulic oil is generated in a pipeline 48 provided with 49, and the spool valve body 42 retreats, whereby hydraulic oil in the pressure chamber 18 is relieved to the bypass passage 14. Therefore, similarly to the first embodiment, a relief pressure characteristic with a small pressure override can be obtained, and the flow rate cutoff characteristic of the hydraulic oil discharged from the pump device can be improved. Other configurations and actions
Since the effect is the same as that of the first embodiment, a detailed description is omitted.

In this embodiment, the adjusting rod 47
Has a characteristic that the discharge flow rate Q decreases as the rotation speed N of the pump shaft 27 increases, with the small diameter portion 47a on the root side and the large diameter portion 47b on the tip side.
The present invention can also be implemented by changing the arrangement of 7a and the large diameter portion 47b so that the characteristics of the discharge flow rate Q with respect to the rotation speed N are different.

[0034]

According to the first aspect of the present invention, the small diameter portion of the spool valve body is slidably fitted to the tubular guide tube having the orifice formed therein, and the hydraulic oil is led out through the guide tube. The pressure after passing was introduced into the annular chamber behind the spool valve body through the damping hole formed in the guide pipe, and the flow control valve was operated to adjust the amount of recirculation from the pressure chamber to the suction port. It is not necessary to form a passage hole in the housing for guiding the pressure after passing to the rear chamber of the spool valve body, and the flow control valve of the pump device can be reduced in size and weight. Moreover, when the operating pressure in the discharge passage exceeds a predetermined value, the pressure in the annular chamber is reduced by the flow of the operating oil generated in the pipe provided with the relief pilot valve, and the spool valve body is retracted to remove the operating oil in the pressure chamber. Relief to bypass passage. That is, since the spool valve element of the flow control valve, which originally has a function of recirculating the hydraulic oil from the vane pump section to the suction port, also functions as a main valve at the time of relief, the relief capacity becomes sufficiently large, and thereby the oil is discharged from the pump device. The flow cutoff characteristic of the hydraulic oil can be improved.

According to the second aspect of the present invention, the discharge port is formed in the rear side plate abutting on the rear side of the vane pump portion, and the pressure chamber is formed between the discharge port and the recess provided in the rear portion of the housing. The formation of the discharge port and the pressure chamber is facilitated.

According to the third aspect of the present invention, since the spool valve element is stopped by the tip of the small diameter portion abutting on the rear side surface of the rear side plate, the spool valve element can be accurately and easily positioned. Can be.

According to the fourth aspect of the present invention, the valve hole of the flow control valve is formed coaxially with the rotor of the vane pump.
As a result, the outer diameter of the pump device does not increase, so that the pump device can be easily mounted on a vehicle or the like.

According to the fifth aspect of the present invention, the variable orifice is formed between the adjusting rod fixed to the rear side plate and the annular projection formed on the small diameter portion of the spool valve body.
The characteristic of the discharge flow rate from the discharge port with respect to the rotation speed of the pump device can be changed.

According to the sixth aspect of the present invention, the spool valve element is stopped by the distal end of the small diameter portion abutting on the rear side surface of the rear side plate, and the adjusting rod and the spool valve element fixed to the rear side plate. Since the variable orifice is formed between the annular projections formed in the small diameter portion, the positioning of the spool valve body can be performed accurately and easily, and the characteristics of the discharge flow rate from the discharge port with respect to the rotation speed of the pump device are improved. Can be changed.

According to the seventh aspect of the present invention, the adjusting rod has a small-diameter portion at the root side fixed to the rear side plate and a large-diameter portion at the tip end, so that the rotational speed of the pump device is increased and the spool valve is increased. As the body retreats, the opening area of the variable orifice decreases, thereby obtaining a pump device having a characteristic that the discharge flow rate from the discharge port decreases in accordance with an increase in rotation speed suitable for a vehicle power steering device. .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an overall structure of a first embodiment of a pump device according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a diagram showing an example of a characteristic of a discharge flow rate with respect to an operating pressure P of the pump device of the embodiment shown in FIG.

FIG. 4 is a longitudinal sectional view showing the entire structure of a second embodiment of the pump device according to the present invention.

5 is a diagram illustrating an example of a characteristic of a discharge flow rate with respect to a rotation speed of the pump device according to the embodiment illustrated in FIG. 4;

[Explanation of symbols]

10 ... housing, 12 ... rear side plate, 14 ...
Bypass passage, 18 pressure chamber, 20 vane pump section,
22 ... rotor, 24 ... suction port, 25 ... discharge port,
Reference numeral 30: guide tube, 30a: damping hole, 32: orifice, 32A: variable orifice, 33: discharge passage, 34:
Discharge port, 40: flow control valve, 41: valve hole, 42: spool valve element, 42a: small diameter portion, 43: spring, 44: annular chamber, 45: communication portion, 46: annular projection, 47: adjustment rod, 47a: small diameter portion, 47b: large diameter portion, 48: conduit.

Claims (7)

[Claims] 1. A vane pump portion provided in a housing and having a rotor rotatably supported around a longitudinal axis, and a discharge port of the vane pump portion formed between the vane pump portion and a rear portion of the housing. A pressure chamber which is opened and communicates with a discharge port via an orifice and a discharge passage; a bypass passage formed in the housing and which communicates the pressure chamber with a suction port side of the vane pump section; And a flow passage control valve provided between the pressure passage and the bypass passage for adjusting the amount of recirculation from the pressure chamber to the suction port side. One end of the stepped cylinder is formed at the rear portion of the housing so as to open and close the bypass passage in the valve hole. And a spool valve body slidably fitted in a valve hole having one end of the bypass passage opened on the side surface, and moved in accordance with a pressure difference between before and after the orifice to change the opening of the flow control valve. At the rear part of the housing, a tubular member having an inner hole forming the discharge passage, protruding coaxially into the valve hole, and slidably fitted into the small diameter portion of the spool valve body. The guide tube is fixed, the orifice is formed in a part of the guide tube, and the guide tube has an annular chamber formed between the guide tube, a rear portion of the housing, and the spool valve body. A damping hole communicating with the discharge passage on the rear side is formed, and a working fluid in the discharge passage is formed in a pipe communicating with the annular chamber and the bypass passage when a pressure in the annular chamber becomes a predetermined value or more. Through the damping hole Pump apparatus, characterized in that a relief pilot valve for discharging the bypass passage. 2. A rear side plate on which the discharge port is formed is in contact with a rear side of the vane pump portion, and the pressure chamber is formed between a rear side surface of the rear side plate and a rear portion of the housing facing the rear side plate. The pump device according to claim 1, wherein the pump device is formed between the pump devices. 3. The spool valve body is urged forward by a spring so that the distal end of the small-diameter portion abuts against the rear side surface of the rear side plate and is stopped, and the distal end of the small-diameter portion of the spool valve body. The pump device according to claim 1, wherein a communication portion communicating the inside and outside of the small-diameter portion is formed in the portion. 4. The pump device according to claim 1, wherein a valve hole of the flow control valve is formed coaxially with a rotor of the vane pump unit. 5. An adjusting rod which is coaxial with the valve hole and which can be inserted into a small-diameter portion of the spool valve body and whose diameter changes along a longitudinal direction is fixed to the rear side plate. The annular projection is formed at the tip of the inner surface of the small-diameter portion of the body, and a variable orifice is formed between the annular projection and the adjustment rod in place of the orifice. Pumping equipment. 6. An adjusting rod, which is coaxial with the valve hole and can be inserted into a small-diameter portion of the spool valve body and changes its diameter along the longitudinal direction, is fixed to the rear side plate. An annular projection is formed at the tip of the inner surface of the small diameter portion of the body, the communication portion is formed at the small diameter portion closer to the tip than the annular projection, and the orifice is provided between the annular projection and the adjustment rod. 5. The pump device according to claim 3, wherein a variable orifice is formed in place of the variable orifice. 7. The adjusting rod has a small-diameter portion on a root side fixed to the rear side plate and a large-diameter portion on a distal end always inserted into a small-diameter portion of the spool valve body. The pump device according to claim 5 or 6, wherein