JPH10175562A - Power steering device - Google Patents

Abstract

(57) [Problem] To provide a power steering device which is hardly affected by steering and can obtain a good steering feeling according to a vehicle speed and a steering load. SOLUTION: Hydraulic oil supplied from a hydraulic pump 41 is regulated by a control valve 20 and supplied to a power cylinder 10, and a part of the hydraulic oil is counteracted by a steering reaction force applying mechanism 30. In the power steering device configured to be supplied to the force hydraulic chamber 31, the flow according to the vehicle speed is controlled by a passage 43 that supplies hydraulic oil from the hydraulic pump 41 to the reaction hydraulic chamber 31 upstream of the control valve 20. A flow control valve 60 for supplying to the force hydraulic chamber 31 is provided, and a valve means 70 for adjusting the opening in accordance with a steering load is provided in a passage P for returning hydraulic oil from the reaction force hydraulic chamber 31 to the reservoir 45.

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, and more particularly to a power steering apparatus whose characteristics change according to a vehicle speed and a steering load (steering amount).

[0002]

2. Description of the Related Art As one of power steering devices, hydraulic oil supplied from a hydraulic pump is regulated by a control valve and supplied to a power cylinder, and a part of the hydraulic oil is steered. There is one configured to be supplied to a reaction force hydraulic chamber of a reaction force application mechanism, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-34473. In the power steering apparatus disclosed in this publication, the hydraulic oil supplied from the control valve to the reaction force hydraulic chamber is controlled according to the vehicle speed by the speed response control unit while returning to the reservoir. Power is gained.

[0003]

In the power steering apparatus disclosed in the above-mentioned publication, the hydraulic oil supplied from the control valve to the reaction force hydraulic chamber returns to the reservoir while the hydraulic oil is returned to the reservoir.
That is, since the speed response control unit is controlled downstream of the control valve in accordance with the vehicle speed, the pressure fluctuation of the hydraulic oil supplied to the reaction force hydraulic chamber due to the steering is large, and the speed response control unit controls the speed. Poor pressure accuracy. Further, although the hydraulic oil supplied to the reaction force hydraulic chamber is controlled by the speed response control unit according to the vehicle speed, it is not controlled according to the steering load, so that a good steering feeling according to the vehicle speed and the steering load is obtained. I can't.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to address the above-described problem, and has an arrangement in which hydraulic oil supplied from a hydraulic pump is regulated by a control valve and supplied to a power cylinder. In a power steering apparatus configured and configured so that a part of the hydraulic oil is supplied to a reaction force hydraulic chamber of a steering reaction force applying mechanism, in the power steering device, the reaction force hydraulic chamber is disposed upstream of the control valve from the hydraulic pump. In the passage for supplying hydraulic oil to the passage, a flow regulating valve for supplying a flow according to the vehicle speed to the reaction force hydraulic chamber is provided, and in the passage for returning the hydraulic oil from the reaction force hydraulic chamber to the reservoir, according to the steering load. It is characterized in that valve means for adjusting the opening degree is provided. In this case, it is desirable to provide the steering reaction force applying mechanism and the valve means integrally.

[0005]

In the power steering apparatus according to the present invention, the flow rate according to the vehicle speed is increased through a flow rate adjustment valve provided in a passage for supplying hydraulic oil from the hydraulic pump to the reaction force hydraulic chamber, upstream of the control valve. Hydraulic fluid is guided to the reaction force hydraulic chamber, so the flow rate of the hydraulic oil supplied to the reaction force hydraulic chamber is less affected by steering and is accurately controlled, and the hydraulic oil is returned from the reaction force hydraulic chamber to the reservoir. The flow rate of hydraulic oil flowing from the reaction force hydraulic chamber toward the reservoir is controlled according to the steering load by the valve means provided in the passage, and as a result, the hydraulic oil pressure in the reaction force hydraulic chamber is reduced to the vehicle speed and the steering load. Accordingly, a good steering feeling according to the vehicle speed and the steering load can be obtained.

In the case where the steering reaction applying mechanism and the valve means are provided integrally, the valve means may have a mechanical structure which does not use an electric device such as an electric load sensor or an electric control device. In addition, the components of the steering reaction force applying mechanism and the valve means can be shared, and the configuration of the power steering device can be simplified, and the power steering device can be manufactured at low cost.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In the power steering apparatus according to the present invention shown in FIG. 1, the hydraulic oil supplied from the constantly driven hydraulic pump 41 through the supply passage 42 is regulated by the control valve 20 and supplied to the power cylinder 10. The hydraulic oil supplied through the branch supply passage 43 branched from the supply passage 42 is supplied to the reaction force hydraulic chamber 31 of the steering reaction force applying mechanism 30. Each hydraulic oil supplied to the force hydraulic chamber 31 is returned to the return passage 44.
Through the reservoir 45.

The control valve 20 includes a valve sleeve 22a formed integrally with an output shaft 22 rotatably mounted on a housing body 21, and a valve sleeve 22a.
a valve rotor 24a integrally rotatably mounted on the input shaft 24, which is rotatably assembled to and protrudes out of the housing through the housing cap 23, and the input shaft 24 and the output shaft 2
The torsion bar 25 connecting the two is a main component, and the relative rotation of the input shaft 24 and the output shaft 22 caused by twisting the torsion bar 25, that is, the relative rotation of the valve rotor 24a and the valve sleeve 22a,
As is well known, the reservoir 4 is supplied from the hydraulic pump 41 and
The supply and discharge of the working oil returning to 5 to and from the power cylinder 10 are controlled.

The output shaft 22 meshes with rack teeth 51a of a well-known rack bar 51 mounted on the housing main body 21 by a pinion 22b, and is connected to the steering wheel (not shown) via the rack bar 51. ing. On the other hand, input shaft 2
4 is connected to the steering wheel 52 at the upper end of FIG. 1 via an intermediate shaft and a steering main shaft (both not shown) so as to be integrally rotatable.

The steering reaction force applying mechanism 30 is a mechanism for applying a steering reaction force to the steering wheel 52 separately from the torsion bar 25, and a ball 32 (input shaft 2
4 is mounted so as to be able to roll in the axial direction in an axial groove formed in the outer periphery of the outer periphery of the housing 4 so as to be movable in the axial direction and to be integrally rotatable. 31, a ring member 34 integrally attached to the tip of the output shaft 22 so as to face the holder 33, and the ring member 34 and the holder 33.
V-shaped grooves 34 in the circumferential direction formed on the opposing surfaces of
a and 33a (three are formed at intervals of 120 degrees in the circumferential direction) and are held by the ball retainer 35 so as to be rollable by the ball retainer 35 (see FIG. 2). And the holder 33 moves in the axial direction against the spring 37 in response to an increase in the steering load (relative rotation between the input shaft 24 and the output shaft 22). I have.

In the steering reaction force applying mechanism 30, a flow rate corresponding to the vehicle speed is supplied to a branch supply passage 43 that supplies hydraulic oil from the hydraulic pump 41 to the reaction force hydraulic chamber 31 upstream of the control valve 20. And a valve means 70 for adjusting the opening in accordance with the steering load in the passage P in the housing for returning the hydraulic oil from the reaction force hydraulic chamber 31 toward the reservoir 45. .

The flow control valve 60 is an electromagnetic valve controlled by an electric control device (not shown) according to the vehicle speed.
In addition, when the vehicle speed is between the middle vehicle speed and the high vehicle speed, the working oil having a flow rate that increases in accordance with the increase in the vehicle speed flows into the reaction force hydraulic chamber 31. On the other hand, the valve means 70 is composed of an annular valve portion 71 formed integrally with the holder 33 and an annular valve seat 72 formed integrally with the housing cap 23. 33 is spring 3
7, the opening formed in the passage formed between the annular valve portion 71 and the annular valve seat 72 is reduced (the passage is narrowed).

In the present embodiment configured as described above, at low vehicle speed, the flow control valve 60 does not allow the hydraulic oil to flow into the reaction force hydraulic chamber 31. Only the mechanical reaction force by the spring 37 is obtained, and the power steering device can be operated with a small operation force. Also, when the vehicle speed is medium to high,
Hydraulic oil having a flow rate that increases in accordance with an increase in vehicle speed flows through the flow control valve 60 to the reaction force hydraulic chamber 31, and hydraulic oil flowing from the reaction force hydraulic chamber 31 to the reservoir 45 through the valve means 70 increases the steering load. And the hydraulic pressure in the reaction force hydraulic chamber 31 increases in accordance with the vehicle speed and the steering load. The reaction force is obtained, and the power steering device can be operated with a heavy operation force according to the vehicle speed and the steering load.

By the way, in this embodiment, the working oil having a flow rate corresponding to the vehicle speed is supplied to the reaction force hydraulic chamber 31 through the flow control valve 60 provided in the supply passage 43 upstream of the control valve 20. The flow rate of the hydraulic oil supplied to the force hydraulic chamber 31 is hardly affected by steering and is controlled with high precision. Further, valve means provided in a passage P in the housing for returning the hydraulic oil from the reaction hydraulic chamber 31 toward the reservoir 45 70 controls the flow rate of the hydraulic oil flowing from the reaction force hydraulic chamber 31 toward the reservoir 45 according to the steering load. As a result, the hydraulic oil pressure in the reaction force hydraulic chamber 31 changes according to the vehicle speed and the steering load. Accurately controlled, a good steering feeling according to the vehicle speed and the steering load can be obtained.

In this embodiment, the valve means 70
Is a mechanical configuration that does not use an electric device such as an electric load sensor or an electric control device. Further, the annular valve portion 71 of the valve means 70 is integrally provided on the holder 33 of the steering reaction applying mechanism 30. In addition, since the annular valve seat 72 of the valve means 70 is provided integrally with the housing cap 23 to share the components, the structure of the power steering device is simplified and the power steering device is simplified. It can be manufactured at low cost.

In the above embodiment, the reaction force hydraulic chamber 31
It is possible to operate the power steering device with a heavy operation force according to the vehicle speed and the steering load when the vehicle speed is from middle vehicle speed to high vehicle speed, in such a manner that the hydraulic pressure of the hydraulic oil acts in the same direction as the spring 37. Although it was made possible, the hydraulic pressure of the hydraulic oil in the reaction force hydraulic chamber was configured to act in the opposite direction to the spring 37, and a heavy operating force corresponding to the vehicle speed and the steering load when the vehicle speed was medium to high. It is also possible to operate the power steering device so that it can be operated. In this case,
The mounting load of the spring 37 is increased, and the hydraulic oil having a flow rate (maximum flow rate at a low vehicle speed) that decreases as the vehicle speed increases flows through the flow control valve to the reaction force hydraulic chamber. It is necessary to configure the opening so as to increase as the steering load increases.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a power steering device according to the present invention.

FIG. 2 shows a ring member, a holder, a ball, and the like shown in FIG.
It is sectional drawing which shows the relationship of a ball retainer.

[Explanation of symbols]

10 Power cylinder, 20 Control valve, 3
0: steering reaction force applying mechanism, 31: reaction force hydraulic chamber, 32: ball, 33: holder, 34: ring member, 35: ball retainer, 36: ball, 37: spring, 41: hydraulic pump, 42: supply passage , 43 ... branch supply passage, 44 ...
Return passage, 45: reservoir, P: passage in housing, 6
0: flow control valve, 70: valve means, 71: annular valve portion, 7
2. An annular valve seat.

Claims (2)

[Claims] A hydraulic fluid supplied from a hydraulic pump is regulated by a control valve and supplied to a power cylinder, and a part of the hydraulic oil is a reaction force hydraulic chamber of a steering reaction force applying mechanism. In a power steering device configured to be supplied to the reaction force hydraulic chamber, a flow rate according to vehicle speed is supplied to the reaction force hydraulic chamber through a passage for supplying hydraulic oil from the hydraulic pump to the reaction force hydraulic chamber upstream of the control valve. A power steering device comprising: a flow control valve to be supplied; and valve means for adjusting an opening in accordance with a steering load in a passage for returning hydraulic oil from the reaction force hydraulic chamber to a reservoir. 2. The power steering apparatus according to claim 1, wherein said steering reaction force applying mechanism and said valve means are provided integrally.