JPH0630480U - Variable displacement vane pump - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent rattling of the cam ring when the control piston is in the initial state. [Structure] A plurality of vanes 13 are attached so as to be retractable in a substantially radial direction of a rotor 1, and the rotor 1 is housed in a cam ring 2. The cam ring 2 is eccentrically housed in the pump body 3 and the arm 5 of the cam ring 2 is connected to the control piston 7 via a connecting pin 6. The stopper portion 16 with which the side surface of the connecting pin 6 abuts the inner peripheral surface of the hole 15 of the pump body 3.
The set load of the control spring 9 is received by the stopper portion 16. When the control piston 7 is in the initial state, the connecting pin 6 contacts the stopper portion 16, and the force of the control spring 9 acts so that the control piston 7 and the connecting pin 6 are brought into close contact with each other.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a variable displacement vane pump used for a power steering device of an automobile.

[0002]

[Prior art]

 Generally, in a vane pump, a plurality of vanes are attached to a rotor that is driven and rotated so that the vanes can move in and out in a substantially radial direction.When the rotor rotates in a cam ring, each vane slides into contact with the inner cam surface of the cam ring to repeat the retracting and Thereby, the volume between the adjacent vanes is increased or decreased to perform the pumping action. In the case of the variable displacement vane pump, the center of rotation of the rotor and the center of the inner cam surface are assembled so as to be eccentric to each other, and the volume between adjacent vanes is controlled by controlling the amount of eccentricity. The rate of discharge of hydraulic oil is adjusted by changing the rate of change of the oil.

As a variable displacement vane pump of this type, those shown in FIGS. 4 and 5 have been developed.

In this vane pump, a cam ring 2 that houses a rotor 1 inside is rotatably attached to a pump body 3 via a pin 4, while an arm 5 extending radially outward of the cam ring 2 is provided. It is linked to a control piston 7 via a connecting pin 6, and when this control piston 7 is actuated by the differential pressure across the orifice (not shown) provided in the pump discharge side passage, the cam ring 2 interlocks with the actuation. The rotor 1 is eccentrically rotated. The control piston 7 is accommodated in a cylinder 8 formed in the pump body 3 together with a control spring 9, and is biased to an initial position by the control spring 9. The control piston 7 is set so as to abut against the bottom wall 8a of the cylinder 8, and the set load of the control spring 9 is received by this bottom wall 8a. A long hole 10 is formed in the central portion of the side surface of the control piston 7. By inserting the end of the connecting pin 6 attached to the arm 5 into the long hole 10, the control piston 7 is formed. It is designed to work smoothly with Cam Ring 2. That is, since the control piston 7 moves linearly in the cylinder hole 8 and the arm 5 swings in an arc around the pin 4, the loci of movement of the two do not match exactly, but the connecting pin 6 By allowing the displacement of the control piston 7 in the direction perpendicular to the axis by the elongated hole 10, the two are smoothly interlocked without restricting their movements.

This similar technique is disclosed, for example, in Japanese Patent Laid-Open No. 49-51607.

[0006]

[Problems to be solved by the device]

 However, in the case of the conventional variable displacement vane pump described above, since the set load of the control spring 9 is received by the bottom wall 8a of the cylinder 8, the space between the side wall of the elongated hole 10 in the width direction and the connecting pin 6 is increased. If there is a gap between the control piston 7 and the control piston 7 in the initial state, the cam ring 2 rattles, which causes vibration noise and the eccentric rotation amount of the cam ring 2 slightly changes, resulting in a discharge flow rate. Easy to be unstable. In particular, the elongated hole 10 formed in the control piston 7 has a relationship with the width of the connecting pin 6 because the displacement of the connecting pin 6 in the longitudinal direction of the elongated hole 10 (displacement in the direction perpendicular to the axis of the control piston 7) must be allowed. Since it is difficult to completely eliminate the gap in the direction, such a problem is relatively likely to occur in the above vane pump.

In view of the above, the present invention prevents the rattling of the cam ring even when the control piston is in the initial state, reduces the generation of vibration noise, and is capable of obtaining a stable discharge flow rate. It is intended to provide a type vane pump.

[0008]

[Means for Solving the Problems]

 As a means for solving the above-mentioned problems, the present invention provides a rotor having a plurality of vanes attached to and retractable from each other in a substantially radial direction, a cam ring which accommodates the rotor therein and eccentrically rotates with respect to the rotor. A variable displacement vane pump including a control piston for hydraulically controlling the amount of rotation of the cam ring, the control piston being biased to an initial position by a control spring and being linked to the cam ring via a connecting component. In the above, the pump body is provided with a stopper portion that comes into contact with the connecting component or the cam ring and receives the set load of the control spring.

[0009]

[Action]

 When the control piston is in the initial state, the connecting part or cam ring is pressed against the stopper part by the force of the control spring, and the force of the control spring acts between the control piston and the connecting part so that they are in close contact with each other. To do.

[0010]

【Example】

 Next, an embodiment of the present invention will be described with reference to FIGS. The same reference numerals are used for the same parts as the conventional one shown in the drawings starting from FIG.

In the drawing, 3 is a pump body, and this pump body 3 is composed of a front body 3a, a center body 3b, a side plate 3c and a rear cover 3d. A drive shaft 11 is rotatably supported by the pump body 3, and the rotor 1 is rotatably supported and coupled to the drive shaft 11. The rotor 1 has a plurality of slots 12 formed substantially radially on the outer peripheral side thereof, and the vanes 13 are housed in the slots 12 so as to be retractable.

Reference numeral 2 denotes a cam ring that houses the rotor 1 therein, and the cam ring 2 is provided with a circular inner cam surface 2 a with which the tips of the vanes 13 are in sliding contact. The cam ring 2 is housed in the internal space of the pump body 3, one end of which is rotatably attached to the front body 3a and the rear cover 3d via a pin 4, and the other end of which is used for rotating operation. The arm 5 is extended outward in the radial direction, and a connecting pin (connecting component) 6 is attached to the tip of the arm 5. The center O'of the inner cam surface 2a of the cam ring 2 is eccentric with respect to the rotation center O of the rotor 1, and this vane pump has both centers O'and O eccentric. When the rotor 1 rotates while the tip of the vane 13 slides on the inner cam surface 2a, each vane 13 repeats the retracting operation in the slot 12, thereby increasing or decreasing the volume between the adjacent vanes 13, 13. Pumps continuously. In addition, reference numerals 20 and 21 in FIG. 2 denote an intake port and a discharge port formed in the rear cover 3d.

Reference numeral 7 is a control piston for controlling the amount of eccentric rotation of the cam ring. The control piston 7 is housed in a cylinder 8 formed in the front body 3a, and the inside thereof is provided with a first oil chamber 14a and a second oil chamber 14a. The oil chamber 14b is defined. The first oil chamber 14a communicates with a front side (upstream side) of an orifice (not shown) provided in the pump discharge side passage, and the second oil chamber 14b communicates with a rear side (downstream side) of the orifice. A control spring 9 for urging the control piston 7 to the initial position is housed therein. Therefore, the control piston 7 operates according to the differential pressure across the orifice when the differential pressure across the orifice exceeds the set load of the control spring 9.

Further, a long hole 10 is formed in a substantially central portion of a side surface of the control piston 7, and an end portion of the connecting pin 6 is fitted into the long hole 10. On the other hand, the front body 3a (pump body 3) is formed with a hole 15 for allowing the displacement of the connecting pin 6, and the inner peripheral surface of the hole 15 serves as the stopper 16 portion in the present invention. There is. When the control piston 7 is in the initial state, the stopper portion 16 comes into contact with the side surface of the connecting pin 6 to receive the set load of the control spring 9 for urging the control piston 7. . The control piston 7 is set so as not to come into contact with the bottom wall 8a of the cylinder 8 in the initial position as shown in FIG.

Since the variable displacement vane pump has the above-described structure, when the rotor 1 rotates in the predetermined direction together with the drive shaft 11, the pump action accompanying the retracting and retracting operation of each vane 13 causes the discharge from the discharge region in the cam ring 2. While the hydraulic oil is discharged to the port 21, the differential pressure across the orifice provided in the pump discharge passage acts on both ends of the control piston 7, and when this differential pressure exceeds the set value, the control piston 7 Will operate according to the pressure difference. When the control piston 7 is operated in this manner, the cam ring 2 interlocks with the control piston 7 via the connecting pin 6, whereby the eccentric amount of the cam ring 2 with respect to the rotor 1 is adjusted appropriately. When the control piston 7 and the cam ring 2 are interlocked with each other, the connecting pin 6 moves in the long hole 10 in the longitudinal direction due to the difference in the movement loci of the two.

The control piston 7 is fixed to the initial position by the force of the control spring 9 until the differential pressure across the orifice reaches a set value. At this time, the force of the control spring 9 is connected. It is received by the stopper portion 16 that abuts the pin 6. Therefore, the force of the control spring 9 acts between the control piston 7 and the connecting pin 6 so as to bring them into close contact with each other, so that the gap between the elongated hole 10 and the connecting pin 6 in the width direction of the elongated hole 10 is temporarily assumed. Even if there is, there is no backlash between the control piston 7 and the connecting pin 6. Therefore, the rattling of the connecting pin 6 and the cam ring 2 is surely prevented, and the generation of vibration noise and the disturbance of the discharge flow rate due to the rattling do not occur.

The embodiment of the present invention is not limited to the one described above. For example, in the above embodiment, the inner surface of the hole 15 formed in the front body 3a is used as the stop spa portion 16 and is connected to the stop spa portion 16. Although the side surface of the pin 6 abuts, the stop ring portion 16 may be arranged at another portion of the pump body 3 and the cam ring 2 itself may abut on the stop button portion 16. Further, the connecting part that links the cam ring 2 and the control piston 7 is not limited to the connecting pin 6, and may be another part.

[0018]

[Effect of device]

 As described above, according to the present invention, the pump body is provided with the stopper portion that comes into contact with the coupling component or the cam ring and receives the set load of the control spring, and when the control piston is in the initial state, the coupling component or the cam ring is pressed against the stopper portion. The force of the control spring acts so as to bring the control piston and the connecting part into close contact with each other, so that even if there is a gap between the connecting part and the control piston, the cam ring does not rattle, and as a result, this rattling occurs. Vibration noise and discharge flow rate disturbance due to sticking will not occur.

[Brief description of drawings]

FIG. 1 is a sectional view taken along the line AA of FIG. 2 showing an embodiment of the present invention.

FIG. 2 is a sectional view showing the same embodiment.

FIG. 3 is a sectional view taken along line BB in FIG. 1 showing the same embodiment.

FIG. 4 is a sectional view showing a conventional technique.

FIG. 5 is a cross-sectional view taken along the line CC of FIG. 4 showing the same technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rotor, 2 ... Cam ring, 6 ... Connection pin (connection part), 7 ... Control piston, 9 ... Control spring, 13 ... Vane, 16 ... Stopper part.

Claims (1)

[Scope of utility model registration request] 1. A rotor having a plurality of vanes attached to and retractable from each other in a substantially radial direction, a cam ring which accommodates the rotor therein and is eccentrically rotated with respect to the rotor, and a rotation amount of the cam ring is hydraulically controlled. A variable displacement vane pump comprising a control piston, the control piston being biased to an initial position by a control spring and being linked to the cam ring via a connecting part, the pump body being provided with the connecting part or the cam ring. A variable displacement vane pump, comprising a stopper portion that abuts and receives the set load of the control spring.