JPS5958186A - Variable-capacity type pump for power steering - Google Patents

Abstract

PURPOSE:To automatically control the discharge flow-rate of a pump so that the discharge flow-rate is reduced furthermore in no-load operation and increased to the necessary discharge flow-rate in handle operation by controlling a cam ring which can be shifted in the radial direction of a rotor, in correspondence with the handle operation. CONSTITUTION:A discharge port 10 and the first operation chamber 11 are allowed to communicate each other through a discharge passage 13, and a discharge port 14 which communicates to a power steering apparatus 15 operated through the operation of a handle 30 is installed onto the second operation chamber 12. A control valve 20 sets a variable throttle valve 19 in the closed state during the no-load operation of the pump, and the throttle area of the passage between the first operation chamber 11 and the second operation chamber 12 is throttled to the min. fixed throttle 18, and a cam ring 15 is transferred to the direction for reducing the amount of eccentricity for a rotor 3 by means of the pressure increasing in the first operation chamber 11, accompanying with the rise of the number of revolution of the pump, and the discharge flow-rate is reduced to a lower value. When the handle is operated, the control valve 20 is opened to reduce the pressure in the first operation chamber 11, and then the cam ring 5 is shifted to the direction for increasing the amount of eccentricity for the rotor 3, and the discharge flow-rate of the pump is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering circulation displacement pump.

The power steering pump is driven by the engine regardless of whether or not the power steering device is in operation. Considering the driving conditions of automobiles, most of the time the steering wheel is not operated, and the pump is operated without load. Therefore, in order to reduce engine horsepower and improve fuel efficiency, it is important to minimize the power loss when the pump is under no load.

Conventionally, pumps commonly used in power steering devices are of the fixed discharge type, and the amount of oil pumped out in proportion to the engine speed is controlled by a flow control device to a constant amount required for the power steering device. Excess oil is refluxed to the suction side.

On the other hand, variable displacement pumps help reduce power loss by changing the pump volume t according to the engine speed, allowing the amount of oil pumped out to be kept constant regardless of the engine speed. Therefore, it is expected to be useful for power steering applications.

Therefore, in the variable displacement pump described above, the present invention aims to further reduce the pump discharge flow rate when the pump is operated under no load, to further reduce the horsepower consumption, and to increase the discharge flow rate to the required level when the handle is operated. The purpose of this system is to improve the fuel efficiency of automobiles by automatically controlling the system in response to steering wheel operations.

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, the reference numeral ``■'' indicates a pump casing, and within this pump casing 1, a rotor 3 with a plurality of vanes 2Y is rotatably supported by a drive shaft 4. A cam ring 5 surrounds the rotor 3 and is movable 1υ in the radial direction thereof. A spring 6 is interposed between one side of the outer periphery of the cam ring 5 and the bong casing, and is pressed toward the other side so as to be biased toward the maximum eccentric position with respect to the rotor 3. A stopper 7 restricts the cam ring 5 at its maximum eccentric position.

It has a suction boat 8 and a discharge boat 10 which communicate with the pump chamber formed by the rotor 3 and the cam ring 5, and the suction boat 8 communicates with a reservoir 9.

The present invention provides the variable displacement pump described above, in which a first action chamber 11 is formed between the outer circumferential surface of the ilt+1 cam ring 5 which is biased by the spring 6 and eccentric, and the pump casing 1 facing the same. Spring 6
A second working chamber 12 is formed between the outer circumferential surface of the cam ring 5 on the side pressed by the cam ring 5 and the pump casing 1 facing the same, and a discharge passage 13 is formed between the discharge boat 10 and the first working chamber 11. The second working chamber 12 is provided with a discharge port 14 which communicates with a power steering device 15 operated by one operation of the handle 30.

Furthermore, the first action chamber 11 has an outlet 16 . Further, the second action chamber 12 is provided with an inlet 17, and the outlet 16 and the inlet 17 are communicated with each other through a communication path. □ In the first embodiment shown in Fig. 1, these communication passages are configured in parallel, one of which is provided with a fixed throttle with the minimum throttle area, and the other communication passage is equipped with a power steering wheel operated by the handle. A variable throttle 19 is provided which is opened and closed by a control valve responsive to an increase in load pressure upon operation of the intake device 15. 21 is a relief valve provided in a passage leading to the reservoir 9.

FIG. 2 shows a second embodiment, in which a variable diaphragm 2 is provided in a single communication path.
There are 6 control valves 21) which open and close variable throttles 26 in response to the rise in load pressure associated with handle operation.
η is the aperture of the variable aperture 26 by the minimum aperture area fs>
, much to the dismay of jP7.

No. 31''7/l shows the third embodiment, and the communication passages are arranged in parallel as in the first embodiment, and one of the communication passages is provided with a fixed aperture with a minimum aperture area of 8α, and the other For one series, a mountain road should be provided with a near solenoid valve 22 that controls the variable throttle 19α.
A control device is connected that inputs a detection signal of the detected steering wheel angle into the controller and opens and closes the linear solenoid pulp 22 using a signal from the controller via a solenoid drive circuit 25.

Next, the operation of the present invention will be explained.゛During no-load operation of the pump when the handle is not operated, the control valve is applied in the first embodiment, and the nulloid valve 22 in the third embodiment is closed to the variable throttles 19 and 19 (ZY, respectively, and the second In the embodiment, the control valve is formed by a variable throttle 26 that constantly opens a minute area.Therefore, the first action chamber 1
The constriction area of the passage between the first and second working chambers 12 is the minimum fixed constriction of 18.180L in the 1.3 embodiment, and 18.180L in the second embodiment.
The cam ring 5 is narrowed by the diaphragm 26 with an engineered area, becoming A1 in FIG. 4, and the pressure that increases in the first working chamber 11 as the pump rotation speed increases causes the cam ring 5 to resist the spring 6 to reduce the amount of eccentricity with respect to the rotor 3. 5, and keep the discharge amount Q relative to the pump rotation speed to a low discharge amount Ql in FIG.

In addition, when the handle is operated, the load pressure increases, so in the first and second embodiments, the control valves G and A are opened in response, and in the third embodiment, the signal of the handle Senna O is In response to this, the linear solenoid pulp n opens, and the narrowed area of the passage between the first working chamber 11 and the second working chamber 12 becomes thick (as shown by A2 in FIG. As the pressure decreases, the cam ring 5 is moved in the direction of increasing the amount of eccentricity with respect to the rotor 3 by the pressing force of the spring 6, and the pump discharge '#, Q is increased as shown in Q2 in Fig. 5.
It is to be discharged to the power steering device @15.

In this way, the variable field type pump according to the present invention can reduce the pump discharge amount during no-load operation when the handle is not operated, and significantly reduce the horsepower consumption during no-load operation. Therefore, it helps improve the fuel efficiency of PI nu+ cars, and has the effect of making the advantages of variable capacity and type pumps for power steering even more advantageous.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is a circuit diagram of a main part of a second embodiment, FIG. 3 is a circuit diagram of a main part of a third embodiment, and FIG. 4 is a circuit diagram of a main part of a third embodiment. Figure 5 shows the discharge during no-load operation of the pump when the handle is not operated and when the pump is operated under load when the handle is operated. It is a curve diagram showing changes in quantity. 1. Fist/Pump casing, 2... Vane, 3-...
Rotor, 4... Drive shaft, 5... Cam ring, 6-φ
・Spring, 7...Stopper, 8...Suction port, 9...Reservoir, 10Φφ・Discharge boat, 11...
-First action chamber, 12...Second action chamber, 13...Discharge passage, J4...Discharge port, 15...Power steering device, 1
6... Outlet, 17... Inlet, 18.18α...
・The minimum fixed aperture is 19.19α, but...the variable aperture is
Addition, addition α...-control valve, n...linear solenoid pulp.

Claims (1)

[Claims] A rotor that has a plurality of vanes and is rotatably supported within a pump casing, a cam ring that surrounds this rotor and is movable in its radial direction, and a spring that urges this cam ring to a maximum eccentric position with respect to the rotor. and a variable displacement pump having a suction boat and a discharge boat communicating with a pump chamber formed by the rotor and the cam ring, the eccentric −f being biased by the spring.
A first action chamber is formed between the outer circumferential surface of the cam ring on the lower side and the pump casing that faces it, and a first action chamber is formed between the outer circumferential surface of the cam ring on the side that is pressed by the spring and the pump casing that faces this. A second action chamber is formed in between, the discharge boat and the first action chamber are communicated with each other, and the discharge boat and the first action chamber are connected to each other.
A power steering device is communicated with the 2nd working chamber, the 1st working chamber and @22nd working chamber are communicated through a throttle, and a control valve is provided which is controlled in response to the opening area t of the throttle. A power steering variable displacement pump featuring a power steering circuit.