JPH1113646A - Vane pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in a pump efficiency caused by position failure of a vane by forming an opening part of a suction port in a shape which is gradually narrowed in the centrifugal direction from the way in the rotor rotating direction. SOLUTION: When a rotor 5 is rotatively driven, a hydraulic oil in a reservoir tank is sucked from an intake port 31 into a pump chamber passing a bypass passage 12 and a suction passage 21, and is delivered into a pressure chamber 13 through a delivery port 35. In this time, a vane 6 positioned opposing to the suction port 31 is vibrated by pressure fluctuation or the like, and is gradually erected by a gradually fluctuating part 32b separated from a rotary center gradually after passing a T-point of an inner rim part 32, even if a tip end of the vane 6 is turned in the suction port 31. And then, the vane 6 is positioned on a regular position when the vane 6 reaches a rear end rim part 34. It is thus possible to prevent failure of the rear end rim part 34 of the suction port 31 caused by turning down of the vane, and it is also possible to prevent deterioration in a pump efficiency caused in association therewith.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane pump used for a power steering device and the like, and more particularly, to a vane pump improved so as to automatically correct a problem of a vane posture in an expansion region (suction section).

[0002]

2. Description of the Related Art A conventional vane pump will be described with reference to FIGS. Reference numeral 40 denotes a cam ring mounted on the front housing 10, and the inner periphery thereof has an elliptical curved cam surface 4.
It is 10. Reference numeral 50 denotes a rotor coaxially housed in the cam ring 40, and the rotor 50 is provided with a plurality of vanes 60 that can protrude and retract in the radial direction. As the rotor 50 rotates, the vanes 60 contact the tips of the vanes 60 with the cam surface 410, and the cam ring 40 and the rotor 5
A plurality of pump chambers P1, P2, and P3 are formed between the two pump chambers. And, the pump chamber P in the expansion region where the vane projects
1, a suction port 310, which will be described later, is connected to a pump chamber P3 in a compression region where the vanes are retracted.
0 are open. Between these areas P1 and P3, there is a pump chamber P2 in a pre-compression area that does not communicate with any of the ports 310 and 350.

[0003] Reference numerals 20 and 30 denote rear wall members provided on both sides of the cam ring 40, the rotor 50, and the vane 60 so as to oppose each other with a small gap (generally, 20 to 30 microns on both sides). The housing and the side plate. These rear housings 20,
The side plate 30 is provided with a pair of the suction port 310 and the discharge port 350 which are respectively recessed at symmetrical positions in the diameter direction.

[0004] The volume of the pump chamber is changed by the rotation of the rotor 50, so that the working oil is sucked from the suction port 310 and discharged from the discharge port 350.

[0005]

In the conventional vane pump described above, the suction port 310 is connected to the pump chamber P1.
It is open to. The radial width of the opening of the suction port 310 is minimum at the leading edge 330 in the rotation direction of the rotor 50 and gradually increases toward the trailing edge 340 according to the elliptical shape of the cam surface 410. , To the rear edge 340. The inner peripheral edge 320 of the suction port 310 substantially coincides with the outer periphery of the rotor 50, and the rear edge 340 substantially coincides with the radial direction of the rotor 50.

When the vane 60 passes through the suction port 310, vibration may occur in the vane 60 due to a pressure change in the pump chamber P1 due to suction of hydraulic oil. At this time, when the vane 60 is inclined in the axial direction of the rotor 50, the suction port 3
The tip of the vane 60 falls into the suction port 310 in the middle of 10 (part D in FIG. 4), and passes through the rear edge 340 of the suction port 310 in the same posture. Then, the rear end edge 3 of the suction port 310 is formed on the surface of the rear housing 20 or the side plate 30 by the tip of the vane 60.
A continuous groove-shaped flaw F is made on 40 (FIG. 5). When the flaw F becomes a certain length or more in the rotation direction of the rotor 50,
The pump chamber P2 in the pre-compression region communicates with the suction port 310 and the discharge port 350 at the same time. That is,
There is a problem that the expansion region P1 and the compression region P3 communicate unintentionally, and the pump efficiency is significantly reduced.

[0007]

In order to solve the above-mentioned problems, in the present invention, a rotor rotatably housed in a cam ring mounted on a housing, and the rotor is provided so as to be able to protrude and retract in a radial direction. A plurality of vanes, and a side wall member for closing a side portion of the cam ring, the side wall member having a suction port opening to an expansion region in the cam ring;
In the vane pump having a discharge port opened in the compression region, a configuration is adopted in which the opening of the suction port gradually narrows in the centrifugal direction from halfway in the rotor rotation direction.

In other words, the distance between the inner peripheral edge of the suction port and the center of rotation of the rotor is fixed within a predetermined range from the tip of the suction port in the direction of rotation of the rotor, and then gradually increased. More specifically, the inner peripheral edge of the suction port is formed into an arc portion that substantially coincides with the outer periphery of the rotor within a predetermined range from the front end side of the suction port in the rotation direction of the rotor, and then gradually moves outward from the outer periphery of the rotor. It is to be a gradually changing part that separates.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. Reference numeral 1 denotes a front housing, and a recess 11 is formed in the front housing 1, and the rear housing 2 closes the recess 11. The side plate 3 and the cam ring 4 are provided in the recess 11.
The side plate 3 is in contact with one side of the cam ring 4 and the rear housing 2 is in contact with the other side. The inner circumference of the cam ring 4 has a cam curve cycle of 1
The cam surface 41 is an elliptical curved surface of 80 degrees, and the rotor 5 is rotatably accommodated in the cam ring 4. The rotor 5 is provided with a plurality of vanes 6 whose tips are in sliding contact with the cam surface 41 so as to be able to come and go in the radial direction. The rotor 5 and the vane 6 have one side slidingly contacting the side plate 3 and the other side slidingly contacting the rear housing 2, respectively.
Function as side wall members for closing the side portions of the cam ring 4. Accordingly, a plurality of pump chambers P1, P2, and P3 are formed between the cam surface 41 of the cam ring 4 and the rotor 5 by the adjacent vanes 6, and these pump chambers change in volume due to the rotation of the rotor 5.

The rear housing 2 and the side plate 3
The sliding contact surface with the rotor 5 has a pair of suction ports 31 corresponding to the pump chamber P1 in the expansion region where the vanes 6 protrude.
However, a pair of discharge ports 35 are respectively formed at symmetrical positions in the diameter direction corresponding to the pump chamber P3 in the compression region where the vanes 6 are retracted. In addition, a back pressure groove 36 communicating with the back pressure chamber 51 of the rotor 5 is formed coaxially with the rotor 5 on the same surface, and the back pressure groove 33 communicates with the discharge port 35 through a communication passage (not shown). ing.

The suction port 31 is provided with suction passages 21 formed in the front housing 1 and the rear housing 2.
The discharge port 35 is connected to a reservoir tank (not shown) through the bypass passage 12 of the front housing 1.
The pump housing 13 communicates with a pump outlet (not shown) via a pressure chamber 13 of the front housing 1. A flow control device (not shown) is provided between the bypass passage 12 and the pressure chamber 13 to return a part of the pressure oil sent from the discharge port 35 to the bypass passage 12 as an excess flow.

In the above configuration, the shape of the suction port 31 of the rear housing 2 and the side plate 3 is a feature of this embodiment. That is, the opening of the suction port 31 is gradually narrowed in the centrifugal direction from the middle in the rotation direction of the rotor 5, in other words, the suction port 3
1 and the distance between the inner peripheral edge 32 of the rotor 5 and the center of rotation of the rotor 5
It is characterized in that it is fixed within a predetermined range from the tip side of the suction port 31 in the rotation direction of the rotor 5 and then gradually increased.

The shape of the suction port 31 is shown in FIG. Although the side plate 3 is used in FIG. 3, a suction port 31 having the same shape as described below is formed at a position facing the rear housing 2. Inner edge 3
Reference numeral 2 denotes an arc portion 32a that substantially coincides with the outer periphery of the rotor 5 from the leading edge 33 to the point T. Next, from the point T to the rear edge 34, the rotor 5
For example, a linear gradually changing portion 32b is located away from the outer periphery of the first member. Here, in the present embodiment, the angle α between the gradually changing portion 32b of the inner peripheral edge portion 32 and the rear edge portion is set to 50.
It is set to about 60 °. This angle α and the T
The position of the point is appropriately determined based on the size of the pump device, a desired flow rate, and the like so as not to impair the pump characteristics. The rear edge 34 extends along the radial direction of the side plate 3, and the edges 32, 33, 34
The spaces are connected by an R shape having an appropriate size.

In the vane pump configured as described above, when the rotor 5 is driven to rotate, the hydraulic oil in the reservoir tank is sucked into the pump chamber from the suction port 31 through the bypass passage 12 and the suction passage 21 and discharged. It is discharged to the pressure chamber 13 through the port 35. At that time, the suction port 31
Even if the vane 6 at the position facing the nozzle vibrates due to pressure fluctuation or the like and the tip of the vane 6 falls into the suction port 31, the vane 6 gradually moves away from the rotation center after passing through the point T of the inner peripheral edge portion 32. The vane 6 is gradually raised by the deformed portion 32b, and when the vane 6 reaches the rear edge portion 34, the vane 6 assumes a normal posture. For this reason, there is no possibility that the rear end edge portion 34 of the suction port 31 will be damaged due to the fall of the vane 6, and the pump efficiency will be deteriorated accordingly.

[0015]

As described above, according to the present invention, with respect to the suction port formed in the pair of side wall members closing the side portions of the cam ring, the opening of the suction port is moved from the middle in the rotor rotation direction to the centrifugal direction. A configuration in which the shape gradually narrows, or the distance between the inner peripheral edge of the suction port and the center of rotation of the rotor is kept constant within a predetermined range from the tip of the suction port in the rotation direction of the rotor, and then gradually increased. Such a configuration was adopted.

Thus, even if the tip of the vane falls into the suction port for some reason, the posture of the vane is corrected before reaching the rear edge of the suction port, and the rear edge is not damaged. For this reason, a defect that occurs continuously at the rear end of the suction port as in a conventional vane pump may cause unintended communication between the compression region and the expansion region. There is no.

Therefore, by using the vane pump according to the present invention, it is possible to provide a highly reliable vane pump which does not cause deterioration of pump efficiency due to a bad posture of the vane.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a vane pump according to an embodiment of the present invention.

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

FIG. 3 is a plan view of a side plate according to the embodiment of the present invention.

FIG. 4 is a sectional view (part) of a conventional vane pump.

FIG. 5 is a plan view showing a relationship between a suction port and a discharge port and a vane according to a conventional vane pump.

FIG. 6 is a plan view showing a conventional vane pump, in which the positions of the vanes are different from those in FIG. 5;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 front housing 11 concave portion 12 bypass passage 13 pressure chamber 2 rear housing 21 suction passage 3 side plate 31 suction port 32 inner peripheral edge 32a arc portion 32b gradually changing portion 33 leading edge 34 rear edge 35 discharge port 36 back pressure Groove 4 Cam ring 41 Cam surface 5 Rotor 51 Back pressure chamber 6 Vane

Claims (3)

[Claims] 1. A rotor rotatably housed in a cam ring mounted on a housing, a plurality of vanes provided on the rotor so as to be able to protrude and retract in a radial direction, and a side wall member closing a side portion of the cam ring. A suction port opening to an expansion region in the cam ring;
A vane pump in which a discharge port opening to a compression region is formed, wherein the opening of the suction port is formed so as to gradually narrow in the centrifugal direction from halfway in the rotor rotation direction. 2. A rotor rotatably housed in a cam ring mounted on a housing, a plurality of vanes provided on the rotor so as to be able to protrude and retract in a radial direction, and a side wall member closing a side portion of the cam ring. A suction port opening to an expansion region in the cam ring;
In a vane pump having a discharge port opened in a compression region, the distance between the inner peripheral edge of the suction port and the center of rotation of the rotor is fixed within a predetermined range from the tip of the suction port in the direction of rotation of the rotor. ， Vane pump characterized by gradually increasing. 3. A rotor rotatably housed in a cam ring mounted on a housing, a plurality of vanes provided on the rotor so as to be able to protrude and retract in a radial direction, and a side wall member closing a side portion of the cam ring. A suction port opening to an expansion region in the cam ring;
In a vane pump having a discharge port opened to a compression region, an inner peripheral edge of the suction port is formed into an arc portion that substantially coincides with a rotor outer periphery in a predetermined range from a suction port tip side in a rotation direction of the rotor. A vane pump characterized by a gradually changing portion gradually moving outward from the outer periphery of the rotor.