JPH1178930A - Power steering device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle power steering device which prevents generation of pressure fluctuation of a hydraulic system caused by disturbance inputted from a tire. SOLUTION: A vehicular power steering device has a torsion bar 50 of which one end is connected with a steering wheel and another end is connected with a pinion shaft 40, a valve shaft 20 mounted to the steering wheel side of the torsion bar 50, and a valve body 30 mounted to the pinion shaft side of the torsion bar 50. In the vehicle power steering device which exchanges hydraulic oil's flowing direction due to relative displacement of the valve shaft 20 and the valve body 30 and controls pressure of the hydraulic oil, the valve body 30 is connected with the torsion bar 50 via C ring 70 which elastically deforms in the rotational direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering apparatus for a vehicle having a rotary control valve.

[0002]

2. Description of the Related Art Conventionally, a power steering apparatus for a vehicle having a rotary control valve has been disclosed in Japanese Utility Model Laid-Open Publication No. Hei 10-10865.
There is an apparatus disclosed in Japanese Patent Application Publication No. 8 (JP-A) No. 8 (1994).

In this vehicle power steering device, the valve shaft and the pinion shaft are connected via a torsion bar, and the valve body and the pinion shaft are connected with pins, so that the valve body and the valve shaft have a relative angle. Generates hydraulic pressure for assisting steering.

[0004]

However, since the valve body and the pinion shaft are connected by pins, when the pinion shaft rotates, the valve body also rotates integrally with the pinion shaft. Therefore, continuous and random disturbance input to the tires during running has caused abnormal noise and vibration. That is, the power steering device is a kind of servo system, and the displacement of the rack bar due to the disturbance leads to the fluctuation of the valve body, causing the vibration of the hydraulic system valve and the accompanying pressure fluctuation. This caused abnormal noise due to pipe vibration and self-excited vibration of the pressure control valve.

An object of the present invention is to provide a vehicular power steering device capable of suppressing the occurrence of pressure fluctuations in a hydraulic system due to disturbance input from tires.

[0006]

According to a first aspect of the present invention, there is provided a power steering apparatus for a vehicle, comprising: an elastic member having one end connected to an input member and the other end connected to an output member; The second valve member attached to the output end side of the attached first valve member and the elastic member, and the direction in which the hydraulic oil flows due to the relative displacement of the first valve member and the second valve member. In the power steering apparatus for a vehicle that performs switching and controls the pressure of the hydraulic oil, the second valve member is connected to the elastic member via elastic means that elastically deforms in a rotational direction.

According to the power steering apparatus for a vehicle according to the first aspect, in the rotary control valve, the second valve member (valve body) is connected to the elastic member (torsion bar) via the elastic means (C ring). By connecting, vibration in the rotation direction of the second valve member can be attenuated as compared with vibration in the rotation direction of the output member (pinion shaft) coupled to the elastic member. Therefore, the relative rotation amount due to the vibration of the first valve member and the second valve member can be reduced, so that the pressure fluctuation due to the external force can be reduced.

According to a second aspect of the present invention, there is provided a power steering apparatus for a vehicle, wherein an elastic member having one end connected to the input member and the other end connected to the output member, and an elastic member attached to the input end side of the elastic member. A first valve member and a second valve member attached to the output end side of the elastic member;
In the power steering apparatus for a vehicle which switches the flow direction of hydraulic oil by controlling the relative displacement of the first valve member and the second valve member and controls the pressure of the hydraulic oil, the second valve member, the output member, A cushioning member is provided between them.

According to the vehicle power steering apparatus of the second aspect, the second valve member (valve body) is provided.
Is fitted to an output member (pinion shaft), and a buffer member is interposed therebetween to quickly attenuate relative displacement due to vibration between the second valve member and the output member, thereby reducing pressure fluctuation due to disturbance. it can.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view of a control valve of the vehicle power steering device. This control valve mainly includes a valve housing 10, a valve shaft (first valve member) 20, a valve body (second valve member) 30, a pinion shaft (output member) 40, and a torsion bar (elastic member) 50. I have.

The valve housing 10 has an inlet port 11 connected to the hydraulic pump P, a return port 12 connected to the reservoir R, and outlet ports 13 connected to respective oil chambers of the power cylinder C. 14 and is fixed to a gear housing (not shown). The gear housing supports the lower end of the pinion shaft 40 (not shown) and also supports a rack bar (also serving as a part of the piston rod in the power cylinder C) that meshes with the pinion 41 of the pinion shaft 40. .

The valve shaft 20 has an upper end connected to a steering wheel (not shown), is formed in a hollow shape, and is rotatably supported by the valve housing 10 via a bearing 61. The lower end is rotatably fitted to the upper end of the pinion shaft 40.

The valve body 30 includes a valve shaft 20
(In relative rotation) to supply and discharge hydraulic oil to and from the power cylinder C.
It is connected via a ring (elastic means) 70 and is arranged coaxially with the valve shaft 20 on the outer periphery of the torsion bar 50.

That is, the fitting hole 30a and the fitting hole 3 are formed at the end of the valve body 30 on the pinion shaft 40 side.
A fitting groove 30b is provided on the outer peripheral portion of Oa, and a coupling pin 30c is provided in the fitting groove 30b.
A cylindrical fitting shaft 40a is provided at an end of the pinion shaft 40 on the valve body 30 side, and a coupling pin 40b is provided at a position facing the coupling pin 30c of the valve body 30.

A rubber bush (cushion member) having a cylindrical damping characteristic is provided on an outer peripheral portion of the fitting shaft 40a.
The fitting shaft 40a is fitted in the fitting hole 30a such that the outer peripheral surface of the bush 72 contacts the inner peripheral surface of the fitting hole 30a of the valve body 30. A coupling pin 30c of the valve body 30 is inserted into a coupling ring 70a provided at one end of the C ring 70 disposed in the fitting groove 30b of the valve body 30, and provided at the other end of the C ring 70. The coupling pin 40b of the pinion shaft 40 is inserted into the coupling ring 70b. Thus, the valve body 30 and the pinion shaft 40 are connected via the C-ring 70 in a state where only relative movement in the rotational direction is possible.

A ring-shaped resin sheet (for reducing friction between the pinion shaft 40 and the valve body 30) is provided between the upper end of the fitting shaft 40a of the pinion shaft 40 and the bottom of the fitting hole 30a. Or a metal sheet) 74 is disposed.

The pinion shaft 40 includes a bearing 62
And rotatably supported by the valve housing 10 via a pin 51 via a pin 51. The torsion bar 50 is connected at a lower end to the pinion shaft 40 and at the upper end to the valve shaft 20 via a pin 52 and a seal ring 53 in a liquid-tight manner.

In the control valve of the power steering apparatus for a vehicle, the valve body 30 is connected to the valve shaft 20.
And relative rotation to supply and discharge hydraulic oil to and from the power cylinder C. When vibration is applied to a rack bar (not shown) by external force, the vibration is applied to the pinion shaft 4.
Conveyed as zero rotational motion. However, since the valve body 30 is connected to the pinion shaft 30 by the C ring 70, the spring constant of the C ring 70 and the valve body 3
At a frequency higher than the resonance frequency determined from the mass of zero, the vibration in the rotation direction of the valve body 30 has a significantly smaller gain than the vibration in the rotation direction of the pinion shaft 40, and the relative rotational displacement with the valve shaft 20 becomes smaller. . Therefore, pressure fluctuation due to external force can be reduced, and generation of abnormal noise and generation of self-excited vibration of the control valve can be prevented.

Since the bush 72 having damping characteristics and rapidly converging the vibration of the relative displacement generated between the valve body 30 and the pinion shaft 40 is provided, the frequency of the input disturbance is adjusted to the resonance point. Even when the distance comes close, the divergence phenomenon can be prevented, and the vibration of the relative displacement occurring between the valve body 30 and the pinion shaft 40 can be quickly converged.

In order to tune the damping frequency, it is better that the friction of the Coulomb type having a non-linear characteristic is small. Therefore, by providing the resin sheet 74 between the valve body 30 and the pinion shaft 40, Friction with the pinion shaft 40 can be reduced.

[0021]

According to the first aspect of the present invention, the relative displacement due to the vibration of the first valve member and the second valve member can be reduced, and the pressure fluctuation due to the external force can be reduced. Therefore, it is possible to prevent generation of abnormal noise and vibration of the control valve due to vibration of the hydraulic piping caused by pressure fluctuation.

According to the second aspect of the present invention, the second
Since the buffer member is interposed between the valve member and the output member, the relative displacement due to the vibration between the second valve member and the output member can be rapidly attenuated, and the pressure fluctuation due to disturbance can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a control valve of a vehicle power steering device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a joint between a valve body and a pinion shaft of the control valve according to the embodiment of the present invention;

[Description of Signs] 10: Valve housing, 20: Valve shaft, 30
... valve body, 40 ... pinion shaft, 50 ... torsion bar, 70 ... C-ring, 72 ... bush, 74 ...
Resin sheet.

Claims (2)

[Claims] An elastic member having one end connected to the input member and the other end connected to the output member; a first valve member attached to the input end side of the elastic member; and an output end of the elastic member. A second valve member mounted on the side of the vehicle, and a power steering apparatus for a vehicle that switches a flow direction of hydraulic oil by relative displacement of the first valve member and the second valve member and controls the pressure of the hydraulic oil. A power steering apparatus for a vehicle, wherein the second valve member is connected to the elastic member via elastic means for elastically deforming in a rotational direction. 2. An elastic member having one end connected to the input member and the other end connected to the output member, a first valve member attached to the input end side of the elastic member, and the output end of the elastic member. A second valve member mounted on the side of the vehicle, and a power steering apparatus for a vehicle that switches a flow direction of hydraulic oil by relative displacement of the first valve member and the second valve member and controls the pressure of the hydraulic oil. A power steering apparatus for a vehicle, comprising a buffer member between the second valve member and the output member.