JP2709408B2 - Power steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is used for a power steering device of an automobile. The present invention relates to a power steering device capable of controlling a reaction force applied to a steering wheel during steering so as not to change significantly.

〔Overview〕

The present invention relates to a power steering apparatus for turning a vehicle with a light steering force by adding hydraulic power, and a reaction force for providing a reaction force to a steering wheel by providing a plurality of V-shaped grooves in an outer peripheral axis direction of a piston in a correction valve. By squeezing and supplying pressure oil to the hydraulic means, a sudden change in reaction force during steering is suppressed.

[Conventional technology]

Applicant has proposed a power steering device comprising a hydraulic auxiliary booster separately installed in the steering device.
−251470.

The configuration and operation of a power steering device using the hydraulic assist booster will be described with reference to FIGS.

This device includes a steering device 2 connected to a steering wheel 1 by a mechanical system, a steering force sensor 3 for electrically detecting a steering force of the steering wheel 1, and a hydraulic pressure generation including a pump 4a and a reservoir 4b for generating a hydraulic pressure. Means 4, a hydraulic auxiliary booster 5 connected to the steering device 2, electromagnetic valves 6a and 6b for introducing pressure oil generated by the hydraulic pressure generating means 4 to the hydraulic auxiliary booster 5, and a steering force sensor 3
And a program control circuit 7 for controlling the electromagnetic valves 6a and 6b. The steering device 2 includes a reaction force hydraulic means 21 for applying a reaction force to the steering wheel 1. 6 includes left and right correction valves 22a and 22b for introducing pressure oil applied to the hydraulic auxiliary booster 5, and the left and right correction valves 22a and 22b have pistons shown in FIG. 6 controlled by solenoid valves 6a and 6b. 220 'is included.

In the conventional device configured as described above, when the steering force sensor 3 detects the start of steering and the return of steering, the program control circuit 7 receives the detection output and controls the solenoid valves 6a and 6b to perform left correction. By operating the valve 22a or the right correction valve 22b to supply the hydraulic oil to the hydraulic auxiliary booster 5 to steer the front wheel 9, the hydraulic oil is supplied to the reaction hydraulic pressure means 21 to apply a reaction force. Further, according to the control of the program control circuit 7,
The reaction force applied to the steering wheel 1 is controlled according to the change in the vehicle speed output from the speed sensor 8.

[Problems to be solved by the invention]

In the conventional power steering device described above, the same hydraulic pressure is applied to the hydraulic assist booster and the reaction force hydraulic means when the correction valve is operated, so that the adjustment of the steering force and the reaction force applied to the steering wheel is not compatible. However, when an attempt is made to secure the hydraulic pressure required to steer the front wheels, the reaction force increases with this, causing a problem that the steering force at the time of steering the steering wheel changes greatly. This gives the driver the impression that the steering wheel suddenly becomes heavy.

The present invention solves such a problem, and provides a power steering device capable of suppressing a large change in steering force, maintaining a balance between added steering force and reaction force, and improving steering performance. The purpose is to:

[Means for solving the problem]

The present invention provides a steering device connected to a steering wheel from a mechanical system, a steering force sensor for electrically detecting a steering force of the steering wheel, a hydraulic pressure generating unit, and a hydraulic auxiliary booster connected to the steering device. An electromagnetic valve for introducing pressure oil generated by the oil pressure generation means to the hydraulic auxiliary booster; and a program control circuit for taking in an output of the steering force sensor and controlling the electromagnetic valve. In a power steering apparatus including a reaction force hydraulic unit that applies a reaction force to a wheel and a correction valve that introduces pressure oil to the hydraulic assist booster to the reaction force hydraulic unit, the operation of the correction valve is controlled by the correction valve. A V-shaped groove is provided for squeezing the pressure oil given to the hydraulic auxiliary booster at the start and supplying the oil to the reaction force hydraulic means. And it features.

[Action]

When the program control circuit receives the detection signal from the steering sensor and operates the correction valve by the solenoid valve, the pressure oil from the hydraulic pressure generating means is supplied to the piston in the correction valve. The supplied pressure oil is throttled by passing through a V-shaped groove provided in the outer peripheral axis direction of the piston, and is discharged to a supply path to the reaction force hydraulic means. In this process, the supply pressure is reduced, and the sudden application of a large pressure is suppressed.

Thus, it is possible to prevent the reaction force from being suddenly applied simultaneously with the steering of the steering wheel, and it is possible to improve the steering performance.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. First
FIG. 2 is a diagram showing the general configuration of a conventional example and an embodiment of the present invention. FIG. 2 is a diagram for explaining steering wheel left / left correction including a hydraulic system of the conventional example. FIG. 3 is a steering wheel neutral in the embodiment of the present invention. FIG. 4 is a view showing the overall configuration at the position, FIG. 4 is a view for explaining left-left correction in the embodiment of the present invention, and FIGS. It is sectional drawing and a perspective view shown.

The embodiment of the present invention includes a steering device 2 connected to a steering wheel 1 by a mechanical system, and a steering force sensor 3 for electrically detecting a steering force of the steering wheel 1.
And a hydraulic pressure generating means 4 including a pump 4a and a reservoir 4b
A hydraulic auxiliary booster 5 connected to the steering device 2, electromagnetic valves 6a and 6b for introducing the hydraulic oil generated by the hydraulic pressure generating means 4 to the hydraulic auxiliary booster 5, and an electromagnetic valve 6a which takes in the output of the steering force sensor 3 Control circuit 7 for controlling, 6b
The steering device 2 includes a reaction force hydraulic means 21 for applying a reaction force to the steering wheel 1, and the reaction force hydraulic means 21 includes a left correction valve 22 a for introducing pressure oil applied to the hydraulic auxiliary booster 5 and a right A further feature of the present invention is that the left and right correction valves 22a and 22b are squeezed with hydraulic oil to be applied to the hydraulic auxiliary booster 5 when the operation of the correction valves is started. , A plurality of V-shaped grooves 221 are provided in the outer peripheral axis direction of the piston 220.

Next, the operation of the embodiment of the present invention thus configured will be described.

First, when the steering wheel 1 is at the neutral position, as shown in FIG. 3, the pressure oil from the pump 4a passes through the reaction force hydraulic means 21 and is returned to the reservoir 4b, and the reaction force is not applied to the steering wheel 1. Will be maintained. at the same time,
The pressure oil supplied to the left correction valve 22a and the right correction valve 22b is held by the solenoid valves 6a and 6b, respectively.

Here, as shown in FIG.
Is turned to the left, the start of steering is detected by the steering force sensor 3, and a detection signal is sent to the program control circuit 7. Upon receiving this detection signal, the program control circuit 7 controls the solenoid valve 6a to operate the left correction valve 22a to move it in the direction of the arrow A.

Due to this movement, the pressure oil supplied from the pump 4a passes through the left correction valve 22a and one of them is sent to the hydraulic chamber a of the hydraulic auxiliary booster 5, and moves the piston in the direction of arrow B to steer the front wheel 9. The local pressure oil that has passed through the left correction valve 22a is directly supplied to one side (the upper part in FIG. 4) of the piston 210 of the reaction force hydraulic means 21, and also passes through the valve 11 and the right correction valve 22b, and On the other side of the piston 210 (lower in FIG. 4)
And a steering force is applied to the steering wheel 1 by the pressure difference between the pressure oils on both sides of the piston 210.

The valve 11 is opened and closed by a stepping motor 10 controlled by the program control circuit 7, and the program control circuit 7
Performs the control corresponding to the vehicle speed based on the detection output from the speed sensor 8, controls the stepping motor 10 so that the steering force becomes heavy with the increase in the vehicle speed, and changes the hydraulic pressure of the reaction force hydraulic means 21.

As shown in FIGS. 5 (a) and 5 (b), a plurality of V-shaped grooves 221 are provided along the outer peripheral axis of the piston 220 in the left correction valve 22a and the right correction valve 22b. It is in.

Here, assuming that the steering wheel 1 is turned to the left, the steering force sensor 3 sends a detection signal to the program control circuit 7, and the program control circuit 7 operates the solenoid valve 6a based on the detection signal, and the left correction valve 22a Is moved in the direction of the arrow A shown in FIGS. 4 and 5.

With the movement of the piston 220, the V-shaped groove 221 is connected to a hydraulic pressure supply path to the reaction force hydraulic means 21 as shown by a broken line in FIG. 5, and the pressure oil supplied from the pump 4a is supplied to the V-shaped groove 221. And is supplied to the reaction force hydraulic means 21.

The pressure oil supplied to the piston 220 passes through the V-shaped groove 221 and is throttled to be released to the hydraulic pressure supply path, so that abrupt pressure is applied to the reaction force hydraulic means 21. As a result, the reaction force applied to the steering wheel during steering does not suddenly change.

Although the above description has been made with respect to left-turn steering, pressure oil is also applied to right-turn steering by passing through the V-shaped groove 221 of the right correction valve 22b. it can.

〔The invention's effect〕

As described above, according to the present invention, an abrupt change in the reaction force applied to the steering wheel during steering can be suppressed, and there is an effect that steering performance can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an entire configuration of a conventional example and an embodiment of the present invention. FIG. 2 is a diagram for explaining a steering wheel left turn left correction including a conventional hydraulic system. FIG. 3 is a diagram showing the overall configuration of the embodiment of the present invention at a steering wheel neutral position. FIG. 4 is a view for explaining left-turn left correction in the embodiment of the present invention. 5 (a) and 5 (b) are a cross-sectional view and a perspective view showing the shape of a piston in a correction valve according to the embodiment of the present invention. FIG. 6 is a sectional view showing a shape of a piston in a correction valve in a conventional example. 1 ... steering wheel, 2 ... steering device, 3 ... steering force sensor, 4 ... hydraulic pressure generating means, 4a ...
Pump, 4b ... Reservoir, 5 ... Hydraulic auxiliary booster, 6
a, 6b: Solenoid valve, 7: Program control circuit, 8:
Speed sensor, 9 ... front wheel, 10 ... stepping motor,
11 ... valve, 21 ... reaction force hydraulic means, 22a ... left correction valve, 22b ... right correction valve, 210, 220, 220 '... piston,
221 V-shaped groove.

Claims (1)

(57) [Claims] 1. A steering device connected to a steering wheel by a mechanical system, a steering force sensor for electrically detecting a steering force of the steering wheel, a hydraulic pressure generating means, and a hydraulic assist booster connected to the steering device. An electromagnetic valve that introduces pressure oil generated by the oil pressure generating means into the hydraulic auxiliary booster; and a program control circuit that takes in an output of the steering force sensor and controls the electromagnetic valve. In a power steering apparatus, comprising: a reaction force hydraulic means for applying a reaction force to a steering wheel; and a correction valve for introducing pressure oil to be applied to the hydraulic assist booster to the reaction force hydraulic means. V-groove for squeezing the pressure oil given to the hydraulic auxiliary booster and supplying the reaction force hydraulic means when Power steering apparatus characterized by comprising.