JPS58162786A - Apparatus for controlling vane type variable displacement pump - Google Patents

Abstract

PURPOSE:To omit a hydraulic cylinder, by employing such an arrangement that both of the confined sections on the suction side and on the discharge side are communicated with each other directly when the line pressure is lower than the set pressure of a regulator valve and a cam ring is moved to a most displaced position by a spring. CONSTITUTION:When the speed of rotation of a rotor 24 is low and the line pressure is lower than the set pressure of a regulator valve 31, oil passages 33 and 34 are communicated with each other by the regulator valve 31, so that the hydraulic pressure in a confined section 32 on the discharge side is introduced into a confined section 35 on the suction side. Resultantly, the hydraulic pressure in the section 32 and that in the section 35 become equal to each other, so that no force due to the hydraulic pressure is acted to a cam ring 21. Therefore, the cam ring 21 pushed to the most displaced position by the force of a spring 25 and the discharge volume is increased. By employing such an arrangement, it is enabled to omit a hydraulic cylinder that has been required for oscillating the cam ring 21 and to reduce the size of a control apparatus for a pump.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a vane type variable displacement pump.

As a conventional control device for a vane type variable displacement pump, there is one shown in FIG. 1, for example. A cam ring 1 of the vane type pump is swingable about a pin 2 as a fulcrum, and a rotor 4 equipped with a vane 3 that is movable in a radial direction is provided on the inner diameter of the cam ring 1. The force exerted by the spring 5 and the force exerted by the piston rod 6a of the hydraulic cylinder 6 act in opposite directions on the cam ring ■/<-1a, and the balance of both forces causes the cam ring l to This is so that the amount of eccentricity is determined. The rotor 4 rotates G in the clockwise direction in FIG. 1, sucks oil from the tank 7 into the suction boat lb through the oil passage 8, and discharges pressure oil from the discharge port 1c to the oil passage 9. The pressure oil in the oil passage 9 is regulated to a predetermined pressure (line pressure) by a control valve IO, and is supplied to hydraulic equipment such as a clutch (not shown). The oil passage 9 is also led to the regulator/lube 11;
When the line pressure of the oil passage 9 is higher than the set pressure, the line pressure is communicated with the hydraulic cylinder 6 via the oil passage 12, and when the line pressure is lower than the set pressure, the oil in the hydraulic cylinder 6 is communicated with the tank 7. It acts to discharge to. With this configuration, when the rotation speed of the rotor 4 is low, the hydraulic cylinder 6
Hydraulic pressure is not supplied to the rotor 4, and the eccentricity reaches its maximum, and
When the rotational speed is high, line pressure is supplied to the hydraulic cylinder 6 to reduce the amount of eccentricity. By doing so, it is possible to ensure the discharge amount during low speed rotation and reduce energy loss during high speed rotation.

However, the conventional vane type variable displacement pump control device described above uses a hydraulic cylinder to control the eccentricity of the cam ring, which requires many parts and increases the price. The present invention was developed by focusing on the above-mentioned problems in conventional vane-type variable displacement pump control devices. It is an object of the present invention to solve the above-mentioned problems by making it possible to communicate with the parts.

Hereinafter, the present invention will be explained based on FIG. 2 of the accompanying drawings showing an embodiment thereof.

First, the configuration will be explained.

The cam ring 21 is swingable about a pin 22, and a rotor 24 is provided on the inner diameter of the cam ring 21 and has a bay 723 that is movable in the radial direction. The spring 2 is attached to the Lenohe 21a that is integrated with the cam ring 21.
5 acts to rotate the cam ring 21 clockwise. The rotor 24 rotates clockwise in FIG. 2, sucks oil from the tank 27 through the oil passage 28 into the I suction boat 21b, and discharges pressure oil from the discharge boat 21C to the oil passage 29. Oil road 29
The pressure oil is regulated to a predetermined pressure (line pressure) by the control valve 30, and is supplied to hydraulic equipment such as a clutch (not shown). The line pressure of the oil passage 29 is guided to the regulator valve 31 as pilot pressure. An oil passage 33 that communicates with the discharge side confinement part 32 of the pump and an oil passage 34 that communicates with the suction side confinement part 35 of the pump are led to the regulator valve 31, and the line pressure as the pilot pressure is guided to the regulator valve 31. When line pressure is higher than the set pressure, both sleeve passages 33 and 34 are cut off, and when line pressure is lower than the set pressure, both sleeve passages 33 and 34 are communicated.

Next, the effect will be explained.

When the rotor 24 rotates clockwise in FIG. 2, the oil in the tank 27 is sucked into the suction boat 21b through the oil passage 28, and is discharged into the oil passage 29 from the discharge boat 21c. In this case, there are two locations (on the suction side and the discharge side) where oil is trapped between the vanes 23. That is, the suction side confinement part 35 is located on the upper side in FIG. 2, and the discharge side confinement part 32 is located on the lower side in FIG. As mentioned above, the discharge side confinement part 32 and the suction side confinement part 35 are connected to the regulator valve 31 by oil passages 33 and 34, respectively. Here, the discharge side confinement part 32 confines the discharge pressure (line pressure) of the discharge boat 21c as it is, so the pressure of the discharge side confinement part 32 is almost equal to the line pressure, and the suction side confinement part 35 is Suction port 2 in negative pressure state
Since the suction side confining portion 35 is closed from 1b, the pressure in the suction side confining portion 35 is approximately O. In the vane type variable displacement pump control device according to the present invention, the eccentricity of the cam ring 21 is controlled as follows by utilizing the pressure difference between the two confining portions 32 and 35. When the rotation speed of the rotor 24 is low and the line pressure does not reach the set pressure of the regulator valve 31, the regulator valve 31 connects the oil passage 33 and the oil passage 34, so that the oil pressure of the discharge side confinement part 32 is reduced. The oil pressure is introduced into the suction side confinement part 35, and the oil pressures of the outlet side confinement part 32 and the suction side confinement part 35 are both approximately equal to the line. Therefore, no hydraulic force acts on the cam ring 21 at all. Therefore, the cam ring 2l is pushed to the maximum eccentric position by the force of the spring 25, and the discharge volume is increased. When the rotation of the rotor 24 becomes faster and the discharge amount increases and the line pressure exceeds the set pressure of the regulator valve 31, the regulator valve 31 is switched, the communication between the oil passage 33 and the oil passage 34 is cut off, and the discharge side is confined. Since the oil in the suction side confinement part 35 is no longer supplied to the suction side confinement part 35, the oil pressure in the suction side confinement part 35 becomes almost zero. Since a hydraulic pressure approximately equal to the line pressure is applied to the discharge side confinement portion 32, a force is applied to the nine cam ring 21 to rotate it counterclockwise in FIG. 2. Therefore, the amount of eccentricity of the cam ring 21 decreases, and the discharge volume decreases. The higher the line pressure, the greater the force acting on the cam ring 21 from the discharge side confinement part 32, and conversely, the greater this force, the smaller the eccentricity and the lower the discharge amount, so the cam ring 21 is balanced at a predetermined position. , control valve 30, each oil passage,
Supply the minimum amount of oil required by all hydraulic circuits, such as oil leakage from clutches, etc.

In the above embodiment, the set pressure of the regulator valve 31 is set to a constant pressure by a spring, but if the discharge amount needs to be temporarily increased depending on the operating condition of the equipment that uses this pump, for example, , the set pressure may be changed by applying a predetermined hydraulic pressure to the regulator valve 31.

As explained above, according to the present invention, the supplement communicating with the discharge side confinement part of the pump and the oil passage communicating with the suction side confinement part of the pump are guided to the regulator valve, and the regulator valve has both the oil A first switching position for communicating the oil passages with each other and a second switching position for cutting off the communication between the two oil passages are provided, and the pump discharge pressure is guided to the regulator valve as a pilot pressure, and when the pump discharge pressure is below the set pressure. The regulator valve is set to the first switching position, and when the pump discharge pressure is higher than the set pressure, the regulator valve is set to the second switching position, and the force that swings the cam ring in the direction of increasing eccentricity is set. Since a spring is provided to constantly act on the cam ring, there is no need for a hydraulic cylinder to swing the cam ring.
The advantage is that the cost can be reduced and the pump control device can be downsized.

In addition, the present applicant achieved the same object as above in Japanese Patent Application No. 56-191861 "Control device for vane type variable displacement pump" by discharging the oil in the discharge side confinement part in a predetermined case. However, when comparing the invention described in Japanese Patent Application No. 56-191861 with the present invention, it is found that the present invention utilizes the hydraulic pressure of the high-pressure discharge side confinement portion as it is without discharging it. This −j control has the advantage that the volumetric efficiency does not decrease.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional vane type variable displacement pump control device, and FIG. 2 is a diagram showing a vane type variable displacement pump control device according to the present invention. 21...Cam ring, 21b...Suction boat, 21
cse number discharge boat, 22... snout bottle, 231... vane, 24... rotor, 25... spring, 27...
War tank, 28 Φ oil passage, 29... oil passage, 30...
Fist control valve, 31...Regulator valve, 3211...Discharge side confinement part, 33Φψ/oil passage, 3
4.q.Oil passage, 35..Fist suction side confinement part. Patent applicant: Nissan Motor Co., Ltd. Representative Patent attorney: Toshiyuki Miyauchi

Claims (1)

[Scope of Claim] A control device for a vane type variable displacement pump in which the discharge amount is varied by adjusting the amount of eccentricity of a cam ring swingably disposed in the inner diameter of the housing from the central axis of the inner diameter of the housing, comprising: An oil passage communicating with the discharge side confinement portion of the pump and an oil passage communicating with the suction side confinement portion of the pump are led to a regulator valve, and the regulator valve is provided with a first switching position for communicating both side passages with each other, A second switching position is provided to cut off communication between both side passages, and the pump discharge pressure is guided as pilot pressure to this regulator valve, so that when the pump discharge pressure is less than the set pressure, the regulator valve is in the first switching position. In addition, when the pump discharge pressure is higher than the set pressure, the regulator valve is set to the second switching position, and a spring is provided that always applies a force to swing the cam ring in the direction of increasing the amount of eccentricity. Control device for vane type variable displacement pump.