JPH04194389A - Variable displacement vane pump - Google Patents

Abstract

PURPOSE:To rotate a pump smoothly by making one side of cam rings, having each elliptical inner circumferential surface of the same form, free of relative rotation around a turning shaft to the other side, while driving the cam ring on one side round to the specific angle position. CONSTITUTION:When a cam ring 3B on one side, having an elliptical inner circumferential surface of the same time form each, is rotated relatively with a cam ring 3A on the other, timing for expanding or contracting volumertrical capacity in a pump chamber to be formed between vanes 2B and 2B is shifted form timing for expanding or contracting the capacity of another pump chamber to be formed between vanes 2A and 2A. Therefore, while the one side pump chamber is in fluid suction operation at the specified rotational position of a rotor 1, the other pump chamber is in fluid discharge operation, or in reverse with it, whereby a fluid flows in from the other pump chamber or flows out to the other with each other. In consequence, each fluid flowing at suction ports 6A, 6B and discharge ports 7A, 7B is decreased, thus pump discharge is regulated for decrement. With this constitution, a pump is smoothly rotatable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable displacement vane pump, and more particularly to a vane pump structure that has a simple mechanism and does not put a load on the rotating shaft.

[Prior Art] Fig. 4 shows a conventional variable displacement type 1 vane pump, in which a rotor 1 that is connected to a rotating shaft 5 and rotates is provided with vanes 2 that protrude radially outward at a plurality of locations on the outer circumference. The tip of each vane 2 comes into contact with the circular inner circumferential surface of a cam ring 3 disposed around the rotor 1, and a pump chamber is formed between the vanes 2.

The cam ring 3 has one side edge in contact with the pump housing 8 via the shaft member 31, and is swingable in the vertical direction in the figure.The cam ring 3 is in the upward swinging state as shown in the figure.
The center of the pump chamber deviates significantly from the center of the rotor 1, and as a result, the volume of the pump chamber gradually expands and then gradually decreases as the vane 2 moves due to rotor rotation. Therefore, the suction port 6 is provided facing the pump chamber whose volume gradually increases.
More fluid is drawn into the pump chamber, and the fluid is compressed and discharged from the pump chamber to a discharge port 7 provided facing the pump chamber whose volume gradually decreases.

In addition, when adjusting the discharge flow rate, use the cam ring 3 mentioned above.
Space 8 formed between the upper half outer peripheral surface and the housing wall
When the pressure of a is changed to swing the cam ring 3 downward against the spring force of the spring member 32 and move its center closer to the rotor center, the change in volume of the pump chamber becomes smaller and the pump discharge amount increases. reduced.

[Problems to be Solved by the Invention] However, in the conventional pump described above, in order to swing the cam ring 3, relatively complicated steps are required, such as providing a shaft member 31 and a spring member 32, or forming a pressure acting space 8a. It requires a mechanism. In addition, the volume of the pump chamber is determined by the cam ring 3.
Due to the structure in which the rotational axis is changed by swinging, only one suction port 6 and one discharge port 7 can be provided on the left and right sides, resulting in pressure imbalance and an excessive load being applied to the rotating shaft 5.

Furthermore, since the inner circumference of the cam ring 3 is a perfect circle, there is also the problem that pressure pulsations cannot be tuned.

The present invention is intended to solve these problems, and aims to provide a variable displacement vane pump that has a relatively simple mechanism, does not apply an excessive load to the rotating shaft, and can easily tune pressure pulsation. do.

[Means for Solving the Problems] To explain the present invention in detail, a plurality of vanes are provided at equal intervals in the circumferential direction on the outer periphery of a circular rotor coupled to a rotating shaft, and the tips of these vanes are arranged around the rotor. A pump chamber is formed between each vane by contacting the inner peripheral surface of the cam ring,
In a vane pump that sucks fluid from a suction port into a pump chamber whose volume gradually expands as the rotor rotates, and compresses and discharges fluid from the pump chamber whose volume gradually decreases as the rotor rotates, the fluid is compressed and discharged from the pump chamber whose volume gradually decreases as the rotor rotates.
, 2B are provided adjacent to each other in the width direction of the rotor 1 so as to be able to operate independently of each other, and the cam rings 3A, 3
B is provided so as to face the pair of vanes 2A and 2B and have the same elliptical inner peripheral surface, and one of the cam rings 3
The cam ring A is made relatively rotatable about the rotation shaft 5 with respect to the other cam ring 3B, and a drive means 4 is provided for rotationally driving the one cam ring 3A to a predetermined angular position.

[Function] In the vane pump having the above configuration, both cam rings 3A,
When the postures of the vanes 3B are completely matched, the volume of the pump chambers formed between the vanes 2A and 2B simultaneously expands or contracts at a predetermined rotational position of the rotor 1. Therefore, the suction port 6 is connected to each pump chamber between the vanes 2A and 2B.
A large amount of fluid is simultaneously sucked in from A and 6B, compressed and discharged to discharge ports 7A and 7B, and the pump discharge amount becomes maximum.

Here, when one cam ring 3B is rotated relative to the other cam ring 3A, the timing at which the volume of the pump chamber formed between the vanes 2B expands or contracts, and the vane 2
The timing of expansion or contraction of the volume of the pump chamber formed between A is different, and at a predetermined rotational position of the rotor l, one pump chamber is in operation of sucking fluid while the other pump chamber is in operation of discharging fluid, or the other pump chamber is in operation of discharging fluid. Conversely, fluid flows into the pump chambers from other pump chambers, or fluid flows out to the other pump chambers. As a result, the fluid flow in the suction port and the discharge port is reduced, and the pump discharge amount is adjusted to be lower.

Since the inner peripheral surfaces of the cam rings 3A and 3B are elliptical, the pump chamber between each vane 2A and 2B repeatedly expands and contracts at two approximately radially symmetrical positions during one revolution of the rotor 1. Therefore, since the suction ports 6A, 6B and the discharge ports 7A, 7B can be provided at symmetrical positions with the rotating shaft 5 in between, the problem of uneven load acting on the rotating shaft 5 due to pressure difference does not occur.

Furthermore, since the inner periphery of the cam ring can be made into an ellipse, the pressure pulsations can be easily tuned, and since a conventional cam ring rocking mechanism is not required, the structure is relatively simple.

[Embodiment] In FIG. 1, a pump housing 8 is formed by connecting a front housing 81 and a rear housing 82 with bolts, and a rotating shaft 5 is provided at the center of the housing supported by a bearing. The rotating shaft 5 is rotated by receiving a rotational force from a pulley 51 fixed to the base end. The center of the circular rotor 1 (Fig. 2) is connected to the outer periphery of the insertion end of the rotating shaft 5 by spline fitting.
A plurality of grooves are formed at equal intervals in the circumferential direction, and vanes 2A and 2B are urged to protrude within these grooves by fluid pressure. A pair of vanes 2A and 2B are provided on each side with one side end surface in sliding contact with each other, and these vanes 2A and 2B operate to protrude or retract independently of each other.

Cam rings 3A and 3B are provided around the rotor 1 to face the vanes 2A and 2B, respectively. It is in contact with the inner peripheral surface, and the inner periphery is an elliptical surface that forms a cam curve.

The tips of the vanes 2A and 2B protruding from the outer circumference of the rotor 1 are in contact with the elliptical inner circumferential surfaces of the cam rings 3A and 3B,
The space between the vanes 2A and 2B forms a pump chamber that is sealed by the plate surface of the side plate 83 that abuts from the side and the end surface of the drive shaft 4, the details of which will be described later.

As these pump chambers move with the rotation of the rotor (arrow in FIG. 2), the volume expands and contracts twice. Thus, suction ports 6A and 6B are formed in the side plate 83 facing the position where the volume of the pump chamber gradually increases, and discharge ports 7A and 6B are formed facing the position where the volume of the pump chamber gradually decreases. 7B is formed. These suction ports 6A, 6B and discharge ports (7A, 7B) are located at approximately symmetrical positions with the rotating shaft 5 in between.

By the way, the cam ring 3A is connected to the fixed side plate 83 by a pin 91 and is immovable, while the cam ring 3B is connected to the end surface of the drive shaft 4 by a pin 92 and is rotated. That is, the drive shaft 4 is a cylindrical body with a closed end, and the outer periphery of the large-diameter tip that passes through the center of the rear housing 82 slides on the inner circumferential surface of the rear housing 82, and is provided in the inner space thereof. The insertion end of the rotating shaft 5 is supported by a bearing.

The drive shaft 4 itself has a thrust bearing 84 disposed between the rear surface of the tip end and the inner wall of the rear housing 82.
It is rotatably supported by.

In the vane pump having the above structure, both cam rings 3A,
When the postures of 3B match (Fig. 3 (1)) -
The pump chamber between the vanes 2A and 2B simultaneously performs a suction stroke or a discharge stroke depending on the rotation angle of the rotor 1, so that a large amount of fluid flows from the suction ports 6A and 6B through the pump chamber to the discharge ports 7A and 7B. is discharged to.

The drive shaft 4 connects the cam ring 3B to the cam ring 3A.
For example, as shown in Fig. 3 (2),
If you shift the cam rings 3A and 3B by 45 degrees from each other,
The suction stroke of the pump chamber between the vanes 2A and the discharge stroke of the pump chamber between the vanes 28 overlap every 45 degrees, and in this overlapping section, fluid flows from the pump chamber in the discharge stroke to the pump chamber in the suction stroke, Fluid suction or fluid discharge from the suction ports 6A, 6B or into the discharge ports 7A, 7B is not substantially performed. Therefore, the pump discharge amount decreases.

Cam ring 3B is rotated further, and cam ring 3
When the relative position with A is shifted by 90 degrees (the state shown in Figure 2), the suction stroke and discharge stroke of the pump chamber between vane 2A and the pump chamber between vane 2B completely overlap, and suction ports 6A and 6B
The flow of fluid from the to the discharge ports 7A and 7B is eliminated, and the pump discharges! becomes zero.

Thus, by rotating the cam ring 3B to an appropriate position using the drive shaft 4, the pump discharge amount can be adjusted.

[Effects of the Invention] As described above, according to the vane pump of the present invention, variable displacement can be achieved with a simpler adjustment mechanism than the conventional mechanism that adjusts the discharge flow rate by the rocking motion of a cam ring. I can do it.

In addition, the inner circumferential surface of the cam ring can be made into an ellipse, and it can be made into a pressure-balanced type with suction ports and discharge ports located at symmetrical positions across the rotation axis, so that uneven loads due to pressure differences are applied to the rotation axis. This ensures smooth pump rotation and improved reliability.

Furthermore, by using the ellipsoidal surface as described above, it is also possible to tune the pressure pulsation.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a vertical cross-sectional view of a vane-bon, and FIG. 2 is a cross-sectional view thereof.
FIG. 3 is an explanatory diagram of its operation, and FIG. 4 is a cross-sectional view of a conventional vane pump. 1... Rotor 2A, 2B... Vane 3A, 3B... Cam ring 4... Drive shaft (drive means) 5... Rotating shaft 6A, 6B... Suction port 7A, 7B... Discharge Port 8...Pump housing Fig. 1 Fig. 2 i3 Fig. 3 Fig. 4

Claims (1)

[Claims] A plurality of vanes are provided on the outer periphery of a circular rotor connected to a rotating shaft at equal intervals in the circumferential direction, and the tips of these vanes are brought into contact with the elliptical inner circumferential surface of a cam ring arranged around the rotor to create a pump between each vane. A vane pump that sucks fluid from a suction port into a pump chamber whose volume gradually expands as the rotor rotates, and compresses and discharges fluid from the pump chamber whose volume gradually decreases as the rotor rotates. A pair of the vanes are provided adjacent to each other in the width direction of the rotor so as to be able to operate independently of each other, and the cam ring is provided so as to face the pair of vanes and have the same elliptical inner peripheral surface, one of the cam rings being provided. A variable displacement vane pump characterized in that the variable displacement vane pump is rotatable relative to the other cam ring about the rotation axis, and further includes a drive means for rotationally driving one of the cam rings to a predetermined angular position.