JP2001280263A - Vane pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a fault of chipping off a side wall member as an end surface head end of a vane is caught on a terminal end wall of a discharge port, even if a rotor inversely rotates against the original rotating direction of a pump by air pressure at the time of removing oil by compressed air after performance inspection. SOLUTION: First and second discharge ports 22A and 22B are provided on side walls 13 and 15 to block both side parts of a cam ring 14, and a slope 35 to be gradually deeper in depth in the rotating direction of a rotor 17 is formed on the side wall members 13 and 15 toward starting end parts of these discharge ports 22A and 22B.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane pump used as a hydraulic power source for a power steering device or the like.

2. Description of the Related Art Generally, in a vane pump, the pump is driven on a trial basis for assembly and performance inspection, and after the performance inspection, the pump is drained and shipped. In this kind of vane pump, in order to efficiently perform an oil draining process, compressed air is introduced into a discharge passage from a discharge port of the pump, and oil is extracted from a suction port by an air force. Thus, when compressed air is introduced into the discharge port of the pump, the compressed air acts on the inner end of the vane from the discharge port through the back pressure groove of the vane, and presses the vane against the inner surface of the cam ring. In order to define a pump chamber defined by the vanes, air pressure supplied to the pump chamber from the discharge passage via the discharge port acts on two adjacent vanes, and the rotor is rotated by the air pressure. The rotation direction of the rotor is opposite to the original rotation direction of the pump.

For this reason, as shown in FIG. 6A, the vane 1 moves in the direction of the arrow along the discharge port 2 while extending in the radial direction contrary to the operation of the pump. Is applied to the edge 2A of the discharge port 2, the vane 1 is in the most outwardly extended state, and the length guided by the side plate 3 is the shortest.
For this reason, the vane 1 is easily inclined, and the end of the end face of the vane 1 enters the discharge port 2. When the vane 1 approaches the edge 2A of the discharge port 2 in such a state, the end of the end face of the vane 1 that has entered the discharge port 2 is caught on the end wall 2A of the discharge port 2 as shown in FIG. The end wall 2A is scraped off by the vane 1,
The scraped-off debris could become foreign matter and adversely affect the pump. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described conventional problems, and an object thereof is to prevent a problem that a tip of an end surface of a vane is caught on an end wall of a discharge port even when a rotor is rotated by air pressure, so that a problem of chipping is prevented. It is assumed that.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a rotor rotatably housed in a cam ring mounted on a housing and a slit formed in the rotor. A plurality of vanes housed slidably in the radial direction, and a pair of side wall members provided on both sides of the cam ring. In a vane pump in which discharge ports and first and second suction ports are provided alternately on a circumference and diametrically opposed to each other, the rotor member is provided on the side wall member at a start end portion of the first and second discharge ports. Has a slope formed on the end wall of the start end portion so as to prevent the vane from being caught even when the vane rotates in the opposite direction to the operation of the pump. According to a second aspect of the present invention, the slope is formed so that the depth gradually increases toward the end wall of the start end portion. According to the configuration of the first aspect of the present invention, after the performance inspection of the vane pump, when the compressed air is supplied into the vane pump to discharge the oil in the vane pump, the compressed air causes the rotor to rotate in the original rotation direction of the vane pump. And the vane passes through the discharge port portion while extending in the radial direction. Then, when the vane hangs on the edge of the discharge port (the original start end of the vane pump), the vane is in a state of being extended most outward, and in this state, the guide length of the vane by the side wall portion is the shortest. The vane tends to tilt, and the vane may be caught on the edge of the discharge port. However, in the present invention, since the slope is formed at the end wall portion of the discharge port, even if the vane is inclined when passing through the end wall portion of the discharge port, the vane may catch on the end wall of the discharge port. In addition, the generation of foreign matter (debris) can be prevented. Also,
According to the second aspect of the present invention, since the slope whose depth gradually increases toward the end wall of the starting end portion is formed, when the vane passes through the end wall portion of the discharge port, the vane is moved from the discharge port. The slope once falls into a deep part, and then, as the rotor rotates, the slope is corrected by the slope so as to smoothly contact the end face of the side plate.

Embodiments of the present invention will be described below with reference to the drawings. Reference numeral 10 denotes a front housing of the vane pump.
The rear housing 12 is fixed to the front housing 10 so as to close the recess 11. A side plate 13 and a cam ring 14 are housed in the recess 11. The side plate 13 is provided on one side of the cam ring 14, and the rear housing 12 is provided on the other side.
Side surfaces 15 are in contact with each other. The side plate 13 and the rear housing side surface 15 function as side wall members that close both sides of the cam ring 14. On the inner circumference of the cam ring 14, the period of the cam curve is 18
A cam surface 16 which is basically an elliptical curved surface of 0 degrees is formed,
A rotor 17 is rotatably housed in the cam ring 14. The rotor 17 is connected to the front housing 10.
And a rotating shaft 18 rotatably supported by the rear housing 12, and the rotating shaft 18 is rotatably driven by an appropriate driving means such as an automobile engine. A plurality of slits 19 are radially formed in the rotor 17 at equal angular intervals on the circumference, and a plurality of vanes 20 whose leading end surfaces are in sliding contact with the cam surface 16 slide in each slit 19. It is stored as possible. Pressure oil is introduced into the inner end of the slit 19 through a back pressure groove described later, and the vane 20 is pressed against the cam surface 16 by the pressure oil. Both ends of these vanes 20 are connected to the side plate 13 and the rear housing side surface 1.
5 are slidably contacted with each other. Accordingly, a plurality of pump chambers P are formed between the cam surface 16 of the cam ring 14 and the rotor 17 by the adjacent vanes 20, and the pump chambers P change in volume due to the rotation of the rotor 17. First and second suction ports 21A and 21B corresponding to a pump chamber in an expansion region (suction region) are provided on surfaces of the side plate 13 and the rear housing side surface 15 which are in sliding contact with the rotor 17, and a compression region ( Discharge area)
The first and second discharge ports 22 corresponding to the pump chambers
A and 22B are formed at positions diametrically opposed to each other. The first and second discharge ports 22A,
22B is connected to the discharge port 24 via the discharge passage 23. In the middle of the discharge passage 23, a known flow control valve 2 is provided.
The flow rate control valve 25 controls the flow rate to be sent to the discharge port 24 at a constant level. On the other hand, the first and second suction ports 21A, 21A,
2B is connected to a reservoir (not shown) via a suction passage 26. The surfaces of the rear housing 12 and the side plate 13 which are in sliding contact with the rotor 17 are provided with the first
And the second suction ports 21A, 21B, and the first
And four back pressure grooves 31A, 31B, and 32 communicating with the inside ends of the slits 19 accommodating the vanes 20 radially inward of the second discharge ports 22A, 22B.
A and 32B are recessed coaxially with the rotor 17 and circumferentially separated from each other so as to correspond to the suction ports 21A and 21B and the discharge ports 22A and 22B. The first and second suction-side back pressure grooves 31A, 31B
Are the first and second discharge-side back pressure grooves 32A, 32B adjacent to both sides in the rotation direction of the rotor 17 (the direction of the arrow in FIG. 1).
First and second communication grooves 33, 3 having a throttle effect
4 communicate with each other. Suction-side back pressure grooves 31 corresponding to the first and second suction ports 21A and 21B;
A and 31B are communicated with the discharge passage 23 via an unillustrated introduction passage. Thereby, the suction side back pressure grooves 31A, 3A
1B, discharge oil is introduced through the discharge passage 23 through the introduction passage, and the discharge oil is discharged through the first and second communication grooves 33, 34 into the discharge side back pressure grooves 32A, 32B.
32B. The discharge port 22A,
Start portions 22A1, 22B1 of the rotor 22B in the rotation direction of the rotor.
As shown in detail in FIG. 3 and FIG.
7, a slope 35 whose depth gradually increases in the rotation direction is formed. The slope 35 is connected to the discharge port 22.
A, 22B Start end portions 22A1, 22 in the rotor rotation direction
B1 is deleted, and a wall that interferes with the vane 20 is eliminated at the edges of the start end portions 22A1 and 22B1.
Accordingly, when the rotor 17 rotates in a direction opposite to the original rotation direction when the pump operates, the discharge ports 22A, 22B
Even if the vane 20 passing through is inclined,
Is the start end portion 22 of the discharge ports 22A and 22B.
A1 and 22B1 can be reliably prevented from being caught on the edges. The operation of the present embodiment configured as described above will be described with reference to FIG. When the rotor 17 is rotated in the direction of the arrow by an automobile engine or the like, hydraulic oil is sucked from the first and second suction ports 21A and 21B into the pump chamber P that performs an expansion stroke, and the pump oil from the pump chamber P that performs a compression stroke. First and second discharge ports 22A,
The hydraulic oil is discharged to 22B. Discharge ports 22A, 22
The hydraulic oil discharged from B is controlled to a predetermined flow rate by a flow control valve 25 provided in the discharge passage 23, and is fed from a discharge port 24 to a hydraulic actuation device (not shown) such as a power steering device. Hydraulic oil discharged from the discharge ports 22A and 22B is supplied to the suction-side back pressure groove 3 through an unillustrated introduction passage.
1A and 31B, and further into the discharge side back pressure grooves 32A and 32B via the communication grooves 33 and 34. As a result, pressure oil is introduced into the inner ends of the slits 19 corresponding to the suction side back pressure grooves 31A and 32A and the discharge side back pressure grooves 32A and 32B, and presses the vane 20 toward the cam surface 16. Therefore, when starting the pump, when the vane 20 in the compression stroke is pushed down by the cam surface 16, the pressure oil is pushed out to the discharge side back pressure grooves 32A and 32B, and this is communicated through the communication grooves 33 and 34 to the suction side back pressure. Pressure grooves 31A, 31B
, The vane 20 in the expansion stroke is pushed up toward the cam surface 16. As a result, the vane 20 in the expansion stroke is protruded, and the pumping operation is performed early. By the way, in this kind of vane pump, after assembling the pump, an assembling inspection and a performance inspection before shipment are performed, and the pump is driven to supply and discharge oil under the same conditions as those of an actual vehicle. After discharging the oil remaining in the pump after this inspection, the pump is shipped. FIG. 4 shows a schematic view of discharging the oil after a performance test or the like. In the figure, reference numeral 50 denotes a compressed air supply pipe connected to the discharge port 24. One end of the compressed air supply pipe 50 is connected to a compressed air supply source 51. Is provided. 53 is the inlet 26
The drain pipe 53 is connected to the oil tank 5.
4 is connected. 2 and 4, the on-off valve 52 is operated, and compressed air is supplied from the discharge port 24 into the vane pump through the compressed air supply pipe 50. The compressed air supplied into the vane pump is supplied to the discharge port 22A,
22B is introduced into the suction side back pressure grooves 31A, 31B through the suction side back pressure grooves 31A, 31B, acts on the inner end of the vane 20, and presses the vane 20 against the inner surface of the cam ring 14 by air pressure. Thereby, a plurality of pump chambers on the circumference defined by two adjacent vanes 20 are formed between the cam ring 14 and the rotor 17. On the other hand, compressed air flows from the discharge passage 23 to the discharge ports 22A, 22B.
And is introduced into the pump chamber opening to the discharge ports 22A and 22B. The compressed air introduced into the pump chamber is caused by a difference in pressure receiving area between two adjacent vanes 20.
The rotor 17 is rotated. At this time, the rotation direction of the rotor 17 is opposite to the original rotation direction of the vane pump, and the vane 20 passes through the discharge ports 22A and 22B while jumping out in the radial direction. With the rotation of the rotor 17, the compressed air moves from the pump chamber opening to the discharge ports 22A and 22B to the pump chamber opening to the suction ports 21A and 21B.
21B, the oil is discharged to the oil tank 54 via the suction passage 26 and the oil discharge pipe 53. Such a compressed air discharge port 2
The oil in the pump is discharged by flowing from 2A, 22B to suction ports 21A, 21B. As described above, since the rotation direction of the rotor 17 is opposite to the original rotation direction of the vane pump (the direction opposite to the arrow), when the vane 20 moves while extending in the radial direction along the discharge ports 22A and 22B, When the vane 20 is applied to the start end portions 22A1 and 22B1 of the discharge ports 22A and 22B, the vane 20 is in a state of being extended most outward. In this state, the guide length of the vane 20 by the side plate 13 and the rear housing side surface 15 is the shortest, and the vane 20 is easily inclined. In this state, the vane 20 is moved from the start end portions 22A1, 22B1 of the discharge ports 22A, 22B.
Conventionally, there is a risk that the vane 20 that tends to tilt is caught by the end walls of the discharge ports 22A and 22B, and the end walls are shaved by the vane 20. However, in the present embodiment, the slope 35 that gradually becomes shallower along the rotation direction of the rotor 17 due to the air pressure is provided at the end wall portions of the discharge ports 22A and 22B.
Is formed, even when the vane 20 is inclined at the ends of the discharge ports 22A and 22B, there is no wall with which the vane 20 comes into contact, and the vane 20 is connected to the discharge ports 22A and 22B.
To move away from the end of the side plate 22B, the vane 20 drops from the discharge ports 22A and 22B into a deep portion of the slope 35, and then the slope of the vane 20 is corrected by the slope 35 as the rotor 17 rotates. Alternatively, the rear housing side surface 15
Abuts smoothly on the end face. Therefore, even when the vane 20 passes through a section where the vane 20 is likely to be inclined, the inclination of the vane 20 does not cause the starting end portions 22A1 and 22B1 of the discharge ports 22A and 22B to be cut off, and the debris due to the cut off foreign matter becomes foreign matter and the pump becomes Will not be adversely affected.

As described above, in the present invention, as described above,
A slope was formed on the side wall member that formed the suction port and the discharge port to prevent the vane from being caught on the edge of the discharge port even if the vane was inclined. Even when the pump rotates in the opposite direction to the operation of the pump, the vane does not catch on the end wall of the discharge port. Therefore, the tip end of the vane does not scrape off the end wall of the discharge port, and an effect of preventing foreign matter such as shavings from adversely affecting the vane pump can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall sectional view of a vane pump showing an embodiment of the present invention.

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

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 3;

FIG. 5 is a schematic view for discharging oil from a pump.

FIG. 6 is a view corresponding to FIG. 4 showing a conventional vane pump.

[Explanation of symbols]

 Reference Signs List 10 front housing 11 recess 12 rear housing 13 side plate (side wall member) 14 cam ring 15 rear housing side surface (side wall member) 16 cam surface 17 rotor 18 rotation shaft 19 slit 20 vane 21A, 21B suction port 22A, 22B discharge port 22A1 , 22B1 Start end portion 23 Discharge passage 24 Discharge port 25 Flow control valve 26 Suction passage 31A, 31B Suction side back pressure groove 32A, 32B Discharge side back pressure groove 35 Slope

Claims (2)

[Claims] 1. A rotor rotatably housed in a cam ring mounted on a housing, a plurality of vanes housed slidably in a radial direction in a slit formed in the rotor, and a plurality of vanes on both sides of the cam ring. A pair of side wall members are provided, and first and second discharge ports and first and second suction ports are alternately circumferentially and diametrically arranged on surfaces of the side wall members that are in sliding contact with the rotor. A vane pump provided on the end wall of the first and second discharge ports on the side wall member even when the rotor rotates in a direction opposite to the direction in which the pump is operated. A vane pump having a slope formed to prevent the tire from being caught. 2. The vane pump according to claim 1, wherein the slope is formed so as to gradually increase in depth toward an end wall of the start end portion.