JP3151913B2 - Power steering device steering wheel operation force control device - Google Patents

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 for a vehicle in which an operating force required for operating a steering wheel can be changed according to a vehicle speed.

[0002]

2. Description of the Related Art Conventionally, as this kind of technology, there is one disclosed in Japanese Patent Publication No. 2-1717, for example. In this conventional technology, a reaction oil chamber is provided at both ends of a valve piston,
When the steering wheel is operated, a part of the hydraulic oil is first fixed orifice for restricting the flow rate-one reaction force oil chamber-second fixed orifice for generating damper effect and reaction force oil chamber pressure-variable orifice for vehicle speed response- The third fixed orifice for generating the damper effect and reaction force oil chamber pressure, the other reaction force oil chamber, and the fourth fixed orifice for restricting the flow rate flow sequentially. When the vehicle stops, the variable orifice has the maximum opening at which the orifice effect does not occur, the pressure difference between the two reaction oil chambers is minimized, and the steering operation is light. When the vehicle is running at high speed, the variable orifice has an opening that generates a large orifice effect, the pressure difference between the two reaction force oil chambers is large, and the steering operation is heavy.

The self-excited vibration of the valve piston is suppressed by the damper effect generated by the second and fourth fixed orifices for generating the damper effect and the reaction force oil chamber pressure.

[0004]

However, in the above-mentioned prior art, the use of the fixed orifice for generating the damper effect and the pressure of the reaction oil chamber causes the correlation between the vehicle speed and the operating force to be reduced. As for the setting, there is a problem that the settable range is narrow. In other words, for example, when the operating force is set to be light (to reduce the pressure difference between the two reaction force oil chambers), the fixed orifice is increased. However, the damping effect is reduced, and the self-excited vibration of the valve piston is reduced. Will happen.

Accordingly, it is a technical object of the present invention to solve the above-mentioned problem, that is, to make the setting range of the correlation between the vehicle speed and the operating force wider than that of the prior art.

[0006]

Configuration of the Invention

[0007]

Means for Solving the Problems The technical means of the present invention taken in order to solve the above-mentioned technical problem of the present invention is based on a reciprocating hydraulic operating cylinder device according to the rotation of a handle shaft of a vehicle. A reaction oil chamber is provided at both ends of the valve piston of the control valve device that switches the communication between each cylinder chamber and the hydraulic pump and the reservoir, and a second valve dedicated to generating a damper effect is provided in a communication passage connecting these two reaction oil chambers. 1st and 2nd
A fixed orifice is provided, a variable orifice of vehicle speed response is provided between the two fixed orifices, and a space between the first fixed orifice and the variable orifice of the communication passage is provided via a third fixed orifice for restricting a flow rate. It is connected to a communication passage connecting one of the cylinder chambers to the control valve, and the other of the cylinder chambers is connected between the second fixed orifice and the variable orifice of the communication passage via a fourth fixed orifice for restricting a flow rate. That is, it is connected to a communication passage connecting the control valve.

[0008]

According to the above-described technical means of the present invention, during operation, a part of the hydraulic oil flows sequentially through one of the third and fourth fixed orifices-the variable orifice-the other of the third and fourth fixed orifices, The upstream pressure of the variable orifice is applied to one reaction oil chamber via one of the first and second fixed orifices, and the pressure downstream of the variable orifice is applied to the other via the other of the first and second fixed orifices. Each pressure is supplied to the reaction oil chamber, and the pressure difference between the two reaction oil chambers generates a reaction force opposing the steering wheel operation force.This pressure difference is inversely proportional to the vehicle speed, so the steering wheel operation force is light at low speed running, Also, it becomes heavier at high speeds.

The first and second fixed orifices are used exclusively for generating a damper effect, and the third and fourth fixed orifices are used for limiting the flow rate and do not affect the damper effect. Even if the third and fourth fixed orifices are set large in order to reduce the pressure difference between the reaction oil chambers, the damper effect does not decrease and the self-excited vibration of the valve piston does not occur. it can. That is, the settable range of the correlation between the vehicle speed and the operation force is wider than in the related art.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the technical means of the present invention will be described below in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a control valve device. The control valve device 1 is divided into a right cylinder chamber 2 and a left cylinder chamber 3 by a power piston (not shown), and a housing provided separately from the power piston. 4 and a valve piston 6 that is reciprocated in the housing 4.

The housing 4 includes a passage 8 communicating with the hydraulic pump 7, a passage 10 communicating with the reservoir 9 for storing the hydraulic fluid, and passages 11 and 12 communicating with the right cylinder chamber 2.
It has a passage 11 communicating with the left cylinder chamber 3, a passage 13, and a passage 14 a branching from the passage 14.
4 is in communication with the passages 15 and 16. Passage 8,1
Numeral 0 is open to annular grooves 4a, 4b formed in the inner hole of the inner peripheral wall of the housing 4, respectively. Also, the passage 11 is shown in FIG.
The third fixed orifice 21 and the fourth fixed orifice 22 are respectively arranged as shown in FIG. A variable orifice 23 is provided between the third fixed orifice 21 and the fourth fixed orifice 22.
Are arranged to be incorporated. The third fixed orifice 21 and the fourth fixed orifice 22 are for restricting the flow rate and do not affect the damper effect. 9

The valve piston 6 has an annular groove 6 on its outer periphery.
a, 6b and 6c. The annular groove 6a communicates with the left cylinder 3 through the passages 14a and 13 via the passage 8, and the annular groove 6b communicates with the passage 1 through the passage 8.
1, communicating with the right cylinder chamber 2 via the passage 12,
1, the passage 12 communicates with the reservoir 9 via the passage 10. The annular groove 6c is connected to the passage 11, the passage 1
3 communicates with the reservoir 9 via a passage 10.

Reaction force oil chambers 17, 18 are formed between both sides of the valve piston 6 and between the housings 4, respectively. Each reaction oil chamber 17, 18 has a second fixed orifice 21, 22 disposed in the passage 15, 16. The first fixed orifice 19 and the second fixed orifice 20 pass through the passage 11.
Is in communication with Also, the first fixed orifice 19, the second
The fixed orifice 20 increases the damping effect by reducing the diameter of the orifice and restricting the hydraulic pressure from entering and leaving the reaction oil chambers 17 and 18.

The variable orifice 23 changes its opening in response to the vehicle speed, but is opened at a low speed and narrowed at a high speed.

Next, the operation will be described.

At low speed, the variable orifice 20 is open, and the pressures in the reaction oil chambers 17 and 18 are differential pressures. Here, for example, when an input shaft (not shown) is rotated clockwise, the valve piston 6 moves rightward accordingly,
The annular groove 6b of the valve piston 6 becomes conductive with the annular groove 4a of the housing 4, and the hydraulic fluid from the hydraulic pump 7
On the one hand, passage 8-annular groove 4a-annular groove 6b-passage 11-
The power is supplied to the right cylinder chamber 2 through the path of the passage 12 to assist the movement of the power piston. On the other hand, passage 11
-The third orifice 21-the variable orifice 23-the fourth orifice 22-the annular groove 6c-the annular groove 4b-flowing out to the reservoir 9 via the passage 10 and the passage 15-the first.
It is supplied to the reaction oil chamber 17 via the fixed orifice 19,
The oil is supplied to the reaction oil chamber 18 through the passage 16 and the second fixed orifice 20 through the variable orifice 23. Further, the hydraulic fluid in the left cylinder chamber 3 flows out to the reservoir 9 through the path of the passage 13-the annular groove 6 c-the annular groove 4 b.

The operation when the input shaft is rotated clockwise has been described above, but the variable orifice 23 is also open when the input shaft is rotated counterclockwise. In this state, for example, the valve piston 6 moves leftward, and accordingly, the annular groove 6a of the valve piston 6
Becomes conductive with the annular groove 4a of the valve cylinder 4,
On the one hand, the hydraulic fluid from the hydraulic pump 7 is supplied to the left cylinder chamber 3 via the passage 8-the annular groove 4 a-the annular groove 6 a-the passage 14-the passage 14 a-the passage 13 to assist the movement of the power piston. . Also, on the other hand, passage 14-passage 1
4a-passage 11-fourth fixed orifice 22-variable orifice 23-third fixed orifice 21-passage 11-circular groove 6b-circular groove 4b-flow to reservoir 9 via passage 10, and passage 16- 2 fixed orifice 20
Is supplied to the reaction force oil chamber 18 through the
The oil is supplied to the reaction oil chamber 17 through the passage 15 and the first fixed orifice 19. The working fluid in the right cylinder chamber 2 flows out to the reservoir 9 through a path of the passage 12-the passage 11-the annular groove 6 b-the annular groove 4 b-the passage 10.

As a result, the reaction force hydraulic chambers 17, 18 are moved from the variable orifice 23 to the second fixed orifices 21, 22.
, The pressure difference between the two reaction force hydraulic chambers 16 and 17 is reduced, and an increase in the steering reaction force is appropriately suppressed.

At high speeds, the hydraulic pump 7 can be moved to the right by the input shaft in the same manner as at low speeds.
Is supplied to the right cylinder chamber 2 through the annular groove 6a and assists the movement of the power piston. However, since the diameter of the variable orifice 23 is reduced, the hydraulic fluid passing through the third fixed orifice 21 By controlling the outflow to the reservoir 9 through the fourth fixed orifice 22, the oil is supplied to the reaction oil chamber 17 through the passage 15 -the first fixed orifice 19. The hydraulic fluid in the left cylinder chamber 3 flows out to the reservoir 9 through the annular groove 6c.

When the valve piston 6 is moved to the left by the input shaft, the valve piston 6 operates in the same manner as at low speed and assists the movement of the power piston. However, since the variable orifice 23 is throttled, the fourth fixed orifice 22 is closed. Is supplied to the reaction oil chamber 18 through the passage 16 and the second fixed orifice 20 by controlling the outflow to the reservoir 9 through the third fixed orifice 21. The hydraulic fluid in the right cylinder chamber 2 is supplied to the reservoir 9 through the annular groove 6c.
Leaked to

Therefore, since the variable orifice 23 is throttled, the reaction oil chambers 17 and 18 are in a non-conductive relationship, and the differential pressure of the reaction force between the reaction oil chamber 17 and the reaction oil chamber 18 is increased to increase the valve pressure. By increasing the reaction force to the piston 6, at high speeds,
The steering wheel is heavier than at low speed.

Further, the structure of the power steering device will be easily understood by those skilled in the art, and thus the description and illustration thereof are omitted.

[0024]

As described above, in the present invention, the first and second fixed orifices are exclusively used for generating the damper effect, and
The fourth and fixed orifices are for restricting the flow rate and do not affect the damper effect. For this reason, for example, the third and fourth fixed orifices are set to reduce the operating force (to reduce the pressure difference between the two reaction force oil chambers). Even if it is set to a large value, the damper effect does not decrease, and self-excited vibration of the valve piston can be prevented from occurring. That is, the range in which the correlation between the vehicle speed and the operating force can be set can be made wider than in the related art, and the intended purpose can be achieved.

[Brief description of the drawings]

FIG. 1 is an operation explanatory view of a control valve device showing one embodiment to which the present invention is applied.

[Explanation of symbols]

 Reference Signs List 1 control valve device 2 right cylinder chamber 3 left cylinder chamber 4 housing, 4a, 4b annular groove 5 valve pin 6 valve piston, 6a, 6b, 6c annular groove 7 hydraulic pump 9 reservoir 11, 12, 13, 14, 15, 16 , Passage 17 reaction oil chamber 18 reaction oil chamber 19 first orifice 20 second orifice 21 third orifice 22 fourth orifice 23 variable orifice

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B62D 6/00-6/06 B62D 5/087

Claims (1)

(57) [Claims] A reaction oil is applied to both ends of a valve piston of a control valve device for switching communication between each cylinder chamber of a reciprocating hydraulic operating cylinder device and a hydraulic pump and a reservoir in accordance with rotation of a handle shaft of a vehicle. A first and a second fixed orifice dedicated to the generation of a damper effect in a communication passage communicating the two reaction force oil chambers, and a variable orifice for vehicle speed response positioned between the two fixed orifices. A connection between the first fixed orifice and the variable orifice of the communication passage is connected to a communication passage connecting one of the cylinder chambers and the control valve through a third fixed orifice for restricting a reaction force flow rate, and the communication passage is connected to the communication passage. The second fixed orifice and the variable orifice are connected to the other of the cylinder chambers via the fourth fixed orifice for restricting the flow rate. A steering operation force control device for a power steering device, which is connected to a communication passage connecting to a troll valve.