JP2003184759A - Vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vane pump capable of preventing collision vibration and noise when a vane returns by preventing the vane from being pushed in the direction separating from the cam surface of a cam ring by the generation of surge pressure. <P>SOLUTION: Side plates 7 and 8 are formed with back pressure grooves M, which are communicated with vane back pressure chambers 42 formed at bottoms of the shaft center sides of respective guide slits 41, annularly formed in their end surfaces. The vane back pressure groove M has the delivery pressure guided from a delivery port 82 and comprises large section regions m1, m1, m2, and m2, small section regions m3 and m3 formed between the large section regions m1 and m2, and middle section regions m4 and m4. The small section regions m3 and m3 are formed at bottom positions of the guide slits 41 of the vane 5 in a surge pressure generation region where internal pressure in a pump chamber P suddenly increases when the vane 41 moves to the side of the delivery port 82. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane pump for supplying a working fluid to a vehicle power steering device or the like, and more particularly to a technique for preventing noise and vibration.

[0002]

2. Description of the Related Art In conventional vane pumps, for example,
In Japanese Unexamined Patent Application Publication No. 10-47261, a notch (beard groove) is formed on a surface of a side plate on which a vane is in sliding contact, the opening area being gradually reduced in a direction opposite to a rotation direction of a rotor from a discharge port. By doing so, there is disclosed a technique for mitigating abrupt pressure fluctuation of the discharge pressure and mitigating occurrence of so-called surge pressure in which the pressure in the pump chamber rises abruptly.

[0003]

However, as in the conventional vane pump, it is not possible to cover the entire rotational speed range only by the method of reducing the occurrence of surge pressure by the notch. That is, for example, 500
When a notch shape that is effective in a low speed rotation area of about rotation is set, a surge pressure is generated in a high speed rotation area of about 3000 rotations, and conversely, when a notch shape is set effective in a high speed rotation area of about 3000 rotations, 5
In the low speed rotation region of about 00 rotations, there is a problem that leakage occurs from the notch toward the pump chamber, and the discharge pressure is reduced. Therefore, when the notch shape effective in the low-speed rotation region is set by giving priority to the prevention of the discharge pressure reduction, as shown in FIG. 4 in the pump chamber in the high-speed rotation region as disclosed as a problem in the conventional example, as shown in FIG. A surge pressure is generated, and the surge pressure pushes the vane away from the cam surface of the cam ring, which causes collision vibration and noise when the vane again contacts the cam surface of the cam ring. .

The present invention has been made by paying attention to the above-mentioned conventional problems, and prevents the vane from being pressed in the direction away from the cam surface of the cam ring due to the generation of surge pressure. It is an object of the present invention to provide a vane pump capable of preventing collision vibration and noise when the vane returns.

[0005]

In order to achieve the above object, in a vane pump according to a first aspect of the present invention, a cam ring fitted in a housing, a rotor rotatably accommodated in the cam ring, and the rotor. A plurality of guide slits provided in the radial direction and vanes slidably accommodated in the respective guide slits, a side wall member that abuts both axial end faces of the cam ring and closes both end openings, and the cam ring A plurality of pump chambers defined by the plurality of vanes between the rotor and both side wall members, an intake port opening in an expansion stroke section of the pump chamber, and a compression stroke section of the pump chamber. Discharge port,
In a vane pump provided with a vane back pressure groove formed in at least one of the both side wall members and guiding the discharge pressure of the discharge port to the bottom of each guide slit, the vane back pressure groove includes the vane back pressure groove. The vane back pressure groove is an annular groove opened along the rotary shaft side end of the slit, and has a large cross-sectional area through which the discharge pressure is guided and a small cross-sectional area formed between the large cross-sectional areas. The small cross-sectional area of the vane is formed at the bottom of the guide slit of the vane in the surge pressure generation area where the pressure in the pump chamber rapidly increases when the vane moves to the discharge port side.

According to a second aspect of the present invention, in the vane pump according to the first aspect, the small cross-sectional area of the back pressure groove of the vane is an area where the vane moves to the discharge port side and the pump chamber communicates with the discharge port. The means is formed at the bottom of the guide slit of the vane.

According to a third aspect of the present invention, in the vane pump according to the first or second aspect, a large cross-sectional area of the vane back pressure groove includes an area corresponding to the discharge port and an area corresponding to the suction port. Has a middle cross-sectional area having a cross-sectional area smaller than the large cross-sectional area and larger than the small cross-sectional area, and an inlet port for guiding the discharge pressure from the discharge port to the vane back pressure groove has an intake port larger than the middle cross-sectional area. The means provided in the large cross-sectional area on the side.

A vane pump according to a fourth aspect is the vane pump according to any one of the first to third aspects, wherein the discharge port and the suction port are provided so as to face each other in a diametrical direction about a rotation axis of the rotor. The means to be

[0009]

In the vane pump according to the first aspect of the present invention, as described above, the vane is located at the bottom of the guide slit of the vane in the surge pressure generation region where the pressure in the pump chamber rapidly increases when the vane moves to the discharge port side. Since the small cross-sectional area in the back pressure groove is formed, the vane is pushed toward the bottom of the guide slit that communicates with the small cross-sectional area along the profile of the cam ring, so that the flow resistance is larger than that in the large cross-sectional area. The back pressure at the bottom of the guide slit becomes higher than the discharge pressure due to the throttling action of the small cross section area. Therefore, even if a surge pressure occurs, the back pressure acting on the bottom side prevents the vane from separating from the cam surface of the cam ring, which prevents collision vibration and noise when the vane returns. become able to.

According to a second aspect of the present invention, in the vane pump according to the first aspect, the small cross-sectional area of the vane back pressure groove is in an area where the vane moves to the discharge port side and the pump chamber communicates with the discharge port. By forming the vane at the bottom of the guide slit, the back pressure at the bottom of the guide slit in the surge pressure generation region can be made higher than the discharge pressure.

According to a third aspect of the present invention, in the vane pump according to the first or second aspect, an area corresponding to the discharge port and an area corresponding to the suction port are included in a large cross-sectional area of the vane back pressure groove. Has a middle cross-sectional area having a cross-sectional area smaller than the large cross-sectional area and larger than the small cross-sectional area, and an inlet port for guiding the discharge pressure from the discharge port to the vane back pressure groove has an intake port larger than the middle cross-sectional area. By being provided in the large cross-sectional area on the side, the back pressure in the large cross-sectional area on the discharge port side can be increased compared to the large cross-sectional area on the suction port side by the throttling action of the middle cross-sectional area. It is possible to increase the pressing force of the vane corresponding to the above in the cam ring cam surface direction.

According to a fourth aspect of the present invention, in the vane pump according to any of the first to third aspects, the discharge port and the suction port are provided so as to face each other in a diametrical direction about a rotation axis of the rotor. In this way, the small cross-sectional area where the vane pressing force is maximum becomes diametrically opposed to each other, which balances the vane pressing force applied to the cam ring in the radial direction and suppresses the vibration and noise of the pump. become.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) Embodiment 1 of the present invention will be described in detail below with reference to the drawings. 1 is a vertical sectional side view showing a vane pump according to a first embodiment of the present invention, FIG. 2 is a vertical sectional front view taken along line II-II of FIG. 1, and FIG.
FIG. 3 is a vertical sectional front view of a main part taken along line III-III, in which, 1 is a front housing, 2 is a rear housing, 3 is a cam ring, 4 is a rotor, 5 is a vane, 6 is a rotor shaft, and 7 and 8 are side. A plate (side wall member), 9 is a main flow rate control valve, 10 is a sub flow rate control valve, and 11 is a pulley.

A shaft support hole 13 is formed in the front housing 1 to rotatably support the penetrated rotor shaft 6 by bearings 12, 12. On the other hand, a hollow chamber 14 is formed on a surface of the rear housing 2 which is opposed to the front housing 1 for assembly.
4, the side plate 7, the cam ring 3 (and the rotor 4 having the vanes 5), and the side plate 8 are housed in this order from the bottom side in a state of being circumferentially positioned by the two positioning shafts 15, 15. ing. Then, the side plate 7, the cam ring 3, and the side plate 8
Are assembled while being sandwiched between the bottom of the hollow chamber 14 of the rear housing 2 and the facing surface of the front housing 1.

A cam surface 31 having a cam curve period of 180 degrees is formed on the inner circumference of the cam ring 3. The rotor 4 is provided in the cam ring 3 in a state of being splined to the outer circumference of the rotor shaft 6, and is provided in a plurality of (10) guide slits 41 radially provided on the outer peripheral surface of the rotor 4. The vane 5 is slidably accommodated. The vane 5 has a cam ring 3 at its tip.
The inner peripheral cam surface 31 is always in sliding contact with the inner peripheral cam surface 31.

One side surface of each of the rotor 4 and each vane 5 is provided in a state of sliding contact with the end surfaces of both side plates 7 and 8 so that the inner peripheral cam surface 31 of the cam ring 3 and the outer peripheral surface of the rotor 4 are formed. Between the plurality of (10) vanes 5 are divided into a plurality (10) of pump chambers P
Is formed, and the volume of each pump chamber P is changed by the rotation of the rotor 4 (left rotation in FIG. 2).

A pair of suction ports 81, 81 are formed on the end faces of the side plates 7, 8 corresponding to the pump chambers Pu, Pu for the expansion stroke, and the pump chambers Pd, Pd for the compression stroke are formed. Correspondingly, a pair of discharge ports 82, 8
2 is formed. The intake ports 81, 81 are
It is connected to a reservoir (not shown) through a channel (not shown). Further, the discharge ports 82, 82 are
The working fluid discharge port (not shown) communicates with the working fluid discharge port (not shown) through a flow path (not shown).

On the end face of the side plate 8 where the discharge ports 82 are open, a groove extending from the opening edge of the discharge ports 82 in the direction opposite to the rotation direction of the rotor 4 (counterclockwise in FIG. 2). A notch 83 formed by is formed. The notch 83 constitutes the tip of the discharge port 82 that first starts communication with the pump chamber P that moves in the same direction as the rotor 4 rotates. The notch 83 has an opening width and a direction opposite to the rotation direction of the rotor 4. The depth of the groove is gradually reduced and extended.

On the end faces of the side plates 7 and 8, vane back pressure grooves M communicating with the vane back pressure chambers 42 formed in the bottoms of the guide slits 41 on the axial center side are formed in an annular shape. The vane back pressure groove M is for guiding the discharge pressure from the discharge port 82, and has large cross-section regions m1, m1, m2, m.
2, small cross-section regions m3 and m3 formed between the large cross-section regions m1 and m2, and middle cross-section regions m4 and m4.

The small cross-section regions m3 and m3 are in a surge pressure generation region (see the pressure characteristic diagram of the pump chamber in FIG. 4) in which the pressure in the pump chamber P rapidly increases when the vane 5 moves to the discharge port 82 side. Guide slit 4 of the vane 5
It is formed at one bottom position. That is, the vane 5 is formed at the bottom position of the guide slit 41 of the vane 5 in a region where the vane 5 moves to the discharge port 82 side and the pump chamber P communicates with the discharge port 82.

The middle section area m4 is formed between the area corresponding to the discharge port 82 and the area corresponding to the suction port 81. The vane back pressure groove M communicates with the discharge port 82 via an inlet port (not shown) in the large cross-sectional area m1 closer to the suction port 81 than the middle cross-sectional area m4.

Next, the operation and effect of the first embodiment of the present invention will be described. Since the vane pump according to the first embodiment of the present invention is configured as described above, when the rotor 4 is rotated counterclockwise in FIG. 2 via the rotor shaft 6 by the driving force input to the pulley 11. The hydraulic fluid in the reservoir (not shown) is pumped from each of the suction ports 81 to the pump chamber Pu.
And is discharged from the discharge port 82 in a pressurized state.

At this time, in the pre-compression stroke in which the expansion stroke shifts to the compression stroke, the vane 5 moves from the expansion stroke in a state in which the pump chamber P defined by the two sets of vanes 5 and 5 is open to the suction port 81 side. After transitioning to the pre-compression stroke in which the suction port 81 is completely closed by 5, the notch 83 is first moved from the tip end of the notch 83 in the transition step to the compression stroke in which both pump chambers P open to the discharge port 82 side. By opening in both pump chambers P and gradually changing in the direction in which the opening area increases, abrupt pressure fluctuations on the discharge port 82 side are suppressed.

In the first embodiment of the present invention, as described above, when the vane 5 moves to the discharge port 82 side, the surge pressure generation region where the pressure in the pump chamber P rapidly increases, specifically, the surge pressure generation region. , The vane 5 moves to the discharge port side 82 and the pump chamber P communicates with the discharge port 82, the vane back pressure groove M is located at the bottom position of the guide slit 41 of the vane 5.
In the preliminary compression stroke, the vane 5 is pushed along the profile of the cam ring 3 toward the vane back pressure chamber 42 formed at the bottom of the guide slit 41 communicating with the small cross section region m3. As a result, the vane back pressure chamber 42 is reduced by the throttling action of the small cross-sectional area m3 having a larger flow path resistance than the large cross-sectional areas m1 and m2.
Back pressure is higher than discharge pressure. Therefore, even if a surge pressure is generated, the back pressure acting on the bottom side of the vane 5 prevents the vane 5 from separating from the cam surface 31 of the cam ring 3. Therefore, the vane 5 once separated from the cam surface 31
The effect of being able to prevent the occurrence of collision vibration and noise generated by the return of is obtained.

Further, of the large cross-sectional area in the vane back pressure groove M, the large cross-sectional area m2 corresponding to the discharge port 82.
And a large cross-sectional area m1 corresponding to the suction port 81, a middle cross-sectional area m4 having a cross-sectional area smaller than the large cross-sectional areas m2 and m1 and larger than the small cross-sectional area m3 is formed. The introduction port (not shown) for guiding the discharge pressure from the discharge port 82 is provided in the large cross-section region m1 closer to the suction port 81 than the middle cross-section region m4.
By the throttling action of 4, it is possible to increase the back pressure of the vane back pressure chamber 42 in the large cross-sectional area m2 on the discharge port 82 side compared to the large cross-sectional area m1 on the suction port 81 side, which corresponds to the position of the discharge port 82. It becomes possible to increase the pressing force of the cam ring 3 toward the cam surface 31 of the vane 5.

Since the discharge port 82 and the suction port 81 are provided so as to face each other in the diametrical direction about the rotation axis of the rotor 4, the small cross-sectional area m3 in which the pressing force of the vane 5 is maximized is the diametrical direction. And the pressing force of the vane 5 applied to the cam surface 31 of the cam ring 3 is balanced in the radial direction. Therefore, it becomes possible to suppress the vibration and noise of the pump.

Next, another embodiment of the invention will be described. In the description of the other embodiments of the present invention, the same components as those of the first embodiment of the invention will be designated by the same reference numerals, and the description thereof will be omitted. Only the differences will be described.

(Embodiment 2) A vane pump according to Embodiment 2 of the present invention has a small cross sectional area m3 as shown in FIG. 5 which is an enlarged view of a main portion of a small cross sectional area m3 in a vane back pressure groove M. This is different from the first embodiment of the present invention in that the groove width of the part is formed to have a middle narrow shape. That is, as shown in the pressure characteristic diagram of the pump chamber in FIG. 4, in proportion to the height of the surge pressure, the groove width of the small cross-section area m3 is narrowed in inverse proportion to the height of the surge pressure. The back pressure of the vane back pressure chamber 42 can be increased. Therefore, the surge pressure can be effectively reduced, and the additional effect that the pump chamber pressure after the surge pressure reduction can be smoothly stabilized can be obtained.

Third Embodiment of the Invention A vane pump according to a third embodiment of the present invention is shown in FIG. 6 which is an enlarged view of a main part of a small cross-section area m3 of a vane back pressure groove M, and FIG.
As shown in the cross-sectional view taken along line VII, the small cross-sectional area m3
This is different from the first embodiment of the present invention formed in the same depth in that the bottom of the groove is formed so that the depth of the groove of the part becomes shallower toward the center. Therefore, the same additional effects as those of the second embodiment of the invention can be obtained.

Although the first embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to those of the first embodiment of the present invention, and is within a range not departing from the gist of the present invention. Even if there is a design change or the like, it is included in the present invention.

For example, in the embodiment of the invention, the two side plates 7 and 8 are provided independently of the housing.
The side plate 7 on the rear housing 2 side may be integrally formed with the rear housing 2, the rear cover, and the like. Further, in the embodiment of the invention, the vane back pressure groove M is formed in both the side plates 7 and 8, but it may be formed in either one.

In the embodiment of the invention, the discharge port 82 and the suction port 81 are diametrically opposed to each other about the rotation axis of the rotor 4, respectively. 82 and suction port 81
The present invention can also be applied to the case where each one is.
Further, in the embodiment of the invention, the example in which the notch 83 is provided is shown, but the present invention can be applied to a device not having the notch 83.

[0033]

As described above, in the vane pump according to the first aspect of the present invention, the vane back pressure groove is
The vane is an annular groove opened along the rotation shaft side end of each of the guide slits, and has a large cross-sectional area through which the discharge pressure is guided and a small cross-sectional area formed between the large cross-sectional areas. The small cross-sectional area in the back pressure groove is a means formed at the guide slit bottom position of the vane in the surge pressure generation area where the pump chamber pressure increases rapidly when the vane moves to the discharge port side. Even if a surge pressure is generated, the back pressure acting on the bottom side prevents the vane from separating from the cam surface of the cam ring, which prevents collision vibration and noise when the vane returns. The effect of becoming is obtained.

According to a second aspect of the present invention, in the vane pump according to the first aspect, the small cross-sectional area of the vane back pressure groove is in the area where the vane moves to the discharge port side and the pump chamber communicates with the discharge port. With the means formed at the bottom of the guide slit of the vane, the back pressure at the bottom of the guide slit can be made higher than the discharge pressure in the surge pressure generation region.

According to a third aspect of the present invention, in the vane pump according to the first or second aspect, a large cross-sectional area of the vane back pressure groove includes an area corresponding to the discharge port and an area corresponding to the suction port. Has a middle cross-sectional area having a cross-sectional area smaller than the large cross-sectional area and larger than the small cross-sectional area, and an inlet port for guiding the discharge pressure from the discharge port to the vane back pressure groove has an intake port larger than the middle cross-sectional area. By adopting the means provided in the large cross-sectional area on the side, the back pressure in the large cross-sectional area on the discharge port side can be increased compared to the large cross-sectional area on the suction port side by the throttling action of the middle cross-sectional area. As a result, it is possible to increase the pressing force of the vane corresponding to the discharge port position in the cam ring cam surface direction.

A vane pump according to a fourth aspect is the vane pump according to any one of the first to third aspects, wherein the discharge port and the suction port are provided so as to face each other in a diametrical direction about a rotation axis of the rotor. By adopting this means, the small cross-sectional areas where the vane pressing force is maximized are in a state of facing each other in the diametrical direction.
The pressing force of the vane applied to the cam ring is balanced in the radial direction, and the vibration and noise of the pump can be suppressed.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing a vane pump according to a first embodiment of the present invention.

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

FIG. 3 is a vertical sectional front view of a main part taken along line III-III in FIG.

FIG. 4 is a pump chamber pressure characteristic diagram in the vane pump according to the first embodiment of the present invention.

FIG. 5 is an enlarged view of a main part showing a small cross-sectional area portion in the vane pump according to the second embodiment of the present invention.

FIG. 6 is an enlarged view of a main part showing a small cross-sectional area portion in a vane pump according to a third embodiment of the present invention.

7 is a sectional view taken along line VII-VII of FIG.

[Explanation of symbols]

M vane back pressure groove m1 large section area m2 Large cross-section area m3 Small cross section area m4 middle section area P pump room Pu Pump room for expansion stroke Pd Pump room for compression stroke 1 Front housing 2 rear housing 3 cam ring 31 Cam surface 4 rotor 41 Guide slit 42 Vane back pressure chamber 5 vanes 6 rotor shaft 7 Side plate (side wall member) 8 Side plate (side wall member) 81 Inhalation port 82 Discharge port 83 notches 9 Main flow control valve 10 Sub flow control valve 11 pulley 12 bearings 13 Shaft support hole 14 Hollow chamber 15 Positioning axis

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Claims (4)

[Claims] 1. A cam ring fitted in a housing, a rotor rotatably housed in the cam ring, a plurality of guide slits radially provided in the rotor, and slidably housed in each of the guide slits. Vanes, a side wall member that abuts both axial end surfaces of the cam ring and closes both end openings, and a plurality of pump chambers partitioned by the plurality of vanes between the cam ring, the rotor, and both side wall members. A suction port that opens in an expansion stroke section of the pump chamber, a discharge port that opens in a compression stroke section of the pump chamber, and the guide slits formed in at least one of the side wall members. A vane back pressure groove that guides the discharge pressure of the discharge port to the bottom of the vane back pressure groove, An annular groove opened along the rotation shaft side end of the vane back pressure groove, the annular groove having a large cross-sectional area through which the discharge pressure is introduced and a small cross-sectional area formed between the large cross-sectional areas. A vane pump, wherein a small cross-sectional area is formed at a guide slit bottom position of the vane in a surge pressure generation area where the pressure in the pump chamber rapidly increases when the vane moves to the discharge port side. 2. A small cross-sectional area of the vane back pressure groove is formed at a bottom position of the guide slit of the vane in an area where the vane moves to the discharge port side and the pump chamber communicates with the discharge port. The vane pump according to claim 1. 3. A cross-sectional area between a region corresponding to the discharge port and a region corresponding to the suction port in the large cross-sectional region of the vane back pressure groove is smaller than the large cross-sectional region and smaller than the small cross-sectional region. An inlet having a large middle cross-sectional area and guiding the discharge pressure from the discharge port to the vane back pressure groove is provided in a large cross-sectional area closer to the suction port than the middle cross-sectional area. The vane pump according to 1 or 2. 4. The vane pump according to claim 1, wherein the discharge port and the suction port are provided so as to face each other in a diametrical direction about a rotation axis of the rotor.