JPH10194153A - Hydraulic power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic power steering device which can carry out the steering suppression only in the steering direction liable to strike with an obstacle, and can correct the steering in the steering suppressing direction. SOLUTION: The pressure oil feeding amount for the right side steering auxiliary force generation of a hydraulic actuator 18 for steering auxiliary force generation is reduced depending on the striking posibility in the right side steering time, while the pressure oil feeding amount for the left side steering auxiliary force generation is reduced depending on the striking possibility in the left side steering time. The first regulation valve 61 regulates only the flow of the pressure oil for the left side steering auxiliary force generation, while the second regulation valve 62 regulates only the pressure oil for the left side steering auxiliary force generation. The first correcting steering permission mechanism 66 permits the flow of the pressure oil for the left side steering auxiliary force generation only as a set volume amount, preferentially to the first regulation valve 61, so as to permit the flow of the pressure oil for generating the right side steering auxiliary force only as the set volume value. The second correcting steering permission mechanism 67 permits the flow of the pressure oil for the right side steering auxiliary force generation only as a set volume amount, preferentially to the second regulation valve 62, so as to permits the flow of the pressure oil for generating the left side steering auxiliary force only as the set volume amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power steering device that can prevent a running vehicle from hitting an obstacle.

[0002]

2. Description of the Related Art A hydraulic actuator having a first oil chamber for generating a right steering assist force and a second oil chamber for generating a left steering assist force, and guides pressure oil from a pump to the first oil chamber during right steering. 2. Description of the Related Art A hydraulic power steering apparatus including a control valve for guiding pressure oil from a pump to a second oil chamber during left steering is widely used.

[0003] In such a hydraulic power steering apparatus, the possibility of collision between a vehicle and an obstacle is set in order to prevent the vehicle from colliding with an obstacle on the side or the rear side during a lane change or the like. It has been proposed to perform steering suppression based on the following.

[0004] For example, when an obstacle is detected, the supply of the high-pressure oil to the hydraulic actuator is bypassed to the low-pressure side to cancel the application of the steering assist force. It has been proposed (Japanese Unexamined Patent Publication No.
No. 19274).

[0005] It has also been proposed that when an obstacle is detected, the steering is suppressed by shutting off an oil path for supplying hydraulic oil to the hydraulic actuator and an oil path for discharging hydraulic oil from the hydraulic actuator.

Further, it has been proposed to provide a dedicated actuator for applying a mechanical steering restraining force when an obstacle is detected.

[0007]

However, when the vehicle is traveling at high speed, the steering assist force is small. Therefore, simply canceling the steering assist force does not sufficiently suppress the steering and makes it difficult for the driver to recognize the presence of an obstacle. It is.

Further, a collision with an obstacle can be obtained simply by bypassing a high pressure oil supply oil passage to the hydraulic actuator to a low pressure side, or by shutting off a pressure oil supply oil passage and a pressure oil discharge oil passage to the hydraulic actuator. There is a problem that not only steering in a directional direction but also steering in a steering direction without a possibility of collision is suppressed.

When a mechanical steering restraining force is applied, a dedicated actuator is required and the configuration becomes complicated.

Furthermore, simply suppressing steering in a direction in which a collision is likely to occur will suppress steering equivalent to play, so that if the vehicle is steered in a normal sense, the vehicle will deviate from the intended lane of travel. There is a risk. That is,
When performing straight running or cornering with a fixed steering angle, the driver generally does not hold the steering wheel at a fixed position, but steers left and right within a play range. However, if steering to the left or right is simply suppressed, it is not possible to perform steering to the left or right to eliminate the play after steering to the other left and right by the play amount. Therefore, until the obstacle is gone and the steering suppression is released
The vehicle travels to the left or right more than the intended direction,
There is a problem that it causes meandering.

An object of the present invention is to provide a hydraulic power steering device that can solve the above problems.

[0012]

SUMMARY OF THE INVENTION The present invention provides a hydraulic actuator having a first oil chamber for generating a right steering assist force and a second oil chamber for generating a left steering assist force. The present invention is applied to a hydraulic power steering apparatus including a control valve for guiding pressure oil to an oil chamber and guiding pressure oil from a pump to a second oil chamber during left steering.

According to the present invention, there is provided a hydraulic power steering apparatus comprising: means for detecting an obstacle which may collide in a right steering direction and an obstacle which may collide in a left steering direction; A first flow control valve for suppressing right steering disposed between the control valve and the control valve; a second flow control valve for suppressing left steering disposed between the other oil chamber and the control valve; and a right steering direction. Means for transmitting a right steering suppression signal based on the possibility of collision with an obstacle in the vehicle, and transmitting a left steering suppression signal based on the possibility of collision with an obstacle in the left steering direction, and right steering assistance based on the right steering suppression signal. The first flow control valve is driven so that the pressure oil flow for generating the force is reduced, and the second flow control valve is driven such that the pressure oil flow for generating the left steering assist force is reduced by the left steering suppression signal. Means and one of the oil chambers A first regulating valve for allowing the flow of hydraulic oil for generating left steering assist force without restricting the flow rate between the control valve and the flow of hydraulic oil for generating right steering assist force, and the like; A second oil flow between the oil chamber and the control valve for restricting the flow of the pressure oil for generating the left steering assist force while allowing the flow of the pressure oil for generating the right steering assist force without restricting the flow rate; A regulating valve. With this configuration,
By transmitting a right steering suppression signal based on the possibility of collision with an obstacle in the right steering direction and driving the first flow control valve with the right steering suppression signal, the pressure oil flow for generating the right steering assist force is reduced. As a result, the movement of the hydraulic actuator is suppressed, and a suppressing force for right steering is generated. Also, a left-hand steering suppression signal is transmitted based on the possibility of collision with an obstacle in the left-hand steering direction, and the second flow control valve is driven by the left-hand steering suppression signal. The flow rate decreases, the movement of the hydraulic actuator is suppressed, and a left steering suppression force is generated. In a state where the right steering suppression signal is generated and the left steering suppression signal is not generated, the first control valve is configured to perform left steering between one of the oil chambers in which the first flow control valve is disposed and the control valve. The flow of the pressure oil for generating the assisting force is allowed without restricting the flow rate, and the flow of the pressure oil for generating the right steering assisting force is regulated. Further, in a state where the left steering suppression signal is generated and the right steering suppression signal is not generated, the second regulating valve is disposed between the other oil chamber in which the second flow control valve is disposed and the control valve. The flow of the pressure oil for generating the right steering assist force is allowed without restricting the flow rate, and the flow of the pressure oil for generating the left steering assist force is regulated. This makes it possible to suppress the steering only in the steering direction in which there is a possibility of collision with an obstacle with a simple configuration without using a dedicated actuator.

The present invention further provides a first flow control valve and a first flow control valve.
The control valve is connected in parallel with the control valve, and allows the flow of the hydraulic oil for generating the left steering assist force without restricting the flow rate only for the set volume in preference to the first control valve, and only for the permitted volume to the right. A first modified steering permitting mechanism for permitting the flow of the pressure oil for generating the auxiliary force without restricting the flow rate is connected in parallel with the second flow control valve and the second regulating valve, and has priority over the second regulating valve. The flow of hydraulic oil for generating the right steering assist force is allowed without limiting the flow rate only for the set volume, and the flow of the hydraulic oil for generating the left steering assist force is only limited for the allowed volume. A second correction steering permission mechanism that permits the correction. First
The correction steering permission mechanism allows the flow of the pressure oil for generating the left steering assist force in preference to the first regulation valve without limiting the flow rate only for the set volume. Therefore, in a state where the right steering suppression signal is generated and the left steering suppression signal is not generated, the initial left steering is performed by allowing the flow of the pressure oil only by the set volume integration by the first modified steering permission mechanism. You. Only the permissible amount allows the flow of the pressure oil for generating the right steering assist force without restricting the flow rate, so that the right steering can be performed. As a result, in a state where the right steering suppression signal is generated and the left steering suppression signal is not generated, the right correction steering after the left steering can be performed by the set amount. Further, the second modified steering permitting mechanism allows the flow of the pressure oil for generating the right steering assist force in preference to the second regulating valve without limiting the flow rate only for the set volume. Therefore, in a state where the left steering suppression signal is generated and the right steering suppression signal is not generated, the initial right steering is performed by allowing the flow of the pressure oil only by the set volume integration by the second modified steering allowance mechanism. You. Only the permissible amount is allowed to flow the pressure oil for generating the left steering assist force without restricting the flow rate, so that the left steering can be performed.
As a result, in a state where the left steering suppression signal is generated and the right steering suppression signal is not generated, the left correction steering after the right steering can be performed by a set amount.

In the hydraulic power steering apparatus according to the present invention, each of the corrective steering permission mechanisms includes a cylinder, a piston that can reciprocate by a set stroke within the cylinder,
A spring for applying a pressure for pushing the piston in one direction, the pressure being set to be smaller than the cracking pressure of each regulating valve, and the first of the cylinders of one of the corrective steering permitting mechanisms.
An oil chamber is connected, and a second oil chamber is connected to a cylinder of the other correction steering permission mechanism. In the first correction steering permission mechanism, the flow of the pressure oil for generating the left steering assist force is permitted only in a set volume. As a result, the piston can be moved in one direction by a set stroke against the pressure applied by the spring, and the flow of pressure oil for generating the right steering assist force is allowed only for the allowed volume. Thus, the piston is made movable in the other direction by the spring so that the flow of the hydraulic oil for generating the right steering assist force is allowed only in the set volume in the second modified steering permission mechanism. The piston is allowed to move in one direction by a set stroke against the applied pressure, and the piston is moved to another position so that the flow of pressure oil for generating the left steering assist force is allowed only for the allowed volume. Move in direction It is preferably a function. Thereby, each correction steering permission mechanism can be constituted only by the cylinder, the piston and the spring, and the structure can be simplified.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

A rack and pinion type hydraulic power steering device 1 shown in FIG. 1 includes an input shaft 2 connected to a steering wheel H, and an output shaft 4 connected to the input shaft 2 via a torsion bar 3. . The torsion bar 3 is connected to the input shaft 2 via a pin 5 and to the output shaft 4 via a serration 6. A pinion 7 is formed on the output shaft 4, and steering wheels (not shown) are connected to each end of the rack 8 that meshes with the pinion 7. The input shaft 2 is supported by a valve housing 10 a via a bearing 9, and is supported by an output shaft 4 via a bush 11. The output shaft 4 is a bearing 12,
13, and is supported by the rack housing 10b.
Thus, the rotation of the input shaft 2 due to the steering of the handle H is transmitted to the pinion 7 via the torsion bar 3, and the rotation of the pinion 7 causes the rack 8 to move in the axial direction. The wheels are steered by the movement of the rack 8. Note that oil seals 14, 15 are provided between the input / output shafts 2, 4 and the valve housing 10a. A support yoke 16 for supporting the rack 8 is provided. The support yoke 16 is pressed against the rack 8 by the elastic force of a spring 17.

A hydraulic cylinder 18 is provided as a hydraulic actuator for generating a steering assist force. The hydraulic cylinder 18 includes a cylinder tube constituted by a rack housing 10 b and a piston 2 integrated with the rack 8.
0, and has a first oil chamber 21 for generating a right steering assist force and a second oil chamber 22 for generating a left steering assist force.

Each of the oil chambers 21 and 22 is connected to a rotary hydraulic control valve 23 via a steering suppressing mechanism 50 described later. The control valve 23 includes a cylindrical first valve member 2.
4 and a second valve member 25 inserted into the first valve member 24 so as to be relatively rotatable. The first valve member 24 is rotatably attached to the output shaft 4 via a pin 26. The second valve member 25 is formed integrally with the outer periphery of the input shaft 2.

As shown in FIG. 2, the first valve member 2
A plurality of recesses along the axial direction are formed at equal intervals in the circumferential direction on the inner periphery of the fourth member 4 and the outer periphery of the second valve member 25. The first valve member-side concave portion is composed of four right steering concave portions 27 and four left steering concave portions 28 located at equal intervals in the circumferential direction. The second valve member side recess is composed of four pressure oil supply recesses 29 and four pressure oil discharge recesses 30 located at equal intervals in the circumferential direction. Each right steering recess 2
7 and the left steering recesses 28 are alternately arranged in the circumferential direction,
Each pressure oil supply recess 29 and each pressure oil discharge recess 30 are arranged alternately in the circumferential direction.

Each right steering recess 27 is provided with a first valve member 2.
4 and the first flow passage 31 formed in the valve housing 1
From the first port 32 formed in the steering control mechanism 5
The first oil chamber 21 communicates with the first oil chamber 21 via the first oil chamber. Each left steering recess 28
Is a second flow path 33 formed in the first valve member 24 and a second port 34 formed in the valve housing 10a.
From the second oil chamber 22 via the steering suppression mechanism 50.
As shown in FIG. 1, each pressure oil supply recess 29 is connected to a third flow path 35 formed in the first valve member 24 and an inlet port 36 formed in the valve housing 10a.
Leads to 7. Each pressure oil discharge recess 30 is formed in the first discharge passage 38 formed in the second valve member 25, the passage 47 between the input shaft 2 and the inner and outer circumferences of the torsion bar 3, and the input shaft 2 shown in FIG. 1. Second discharge path 39 and valve housing 10
It communicates with the tank 41 through the discharge port 40 formed in a.

When steering suppression is not performed, the pump 37, the tank 41, and the oil chambers 21 and 22
It communicates via an inter-valve flow path 42 between the inner and outer circumferences of the valve member 24 and the second valve member 25. Between the first valve member side concave portion and the second valve member side concave portion in the inter-valve flow path 42, there are formed throttle portions A, B, C, D whose opening degree changes due to relative rotation of the two valve members 24, 25. , The apertures A, B, C,
The hydraulic pressure acting on the hydraulic cylinder 18 is controlled by the change in the opening degree of D.

FIG. 2 shows the relative positions of the two valve members 24 and 25 at the steering angle midpoint where steering is not performed.
In this state, each pressure oil supply recess 29 and each pressure oil discharge recess 30 communicate with each other via all the throttle portions A, B, C, and D. Therefore, the pressure oil supplied from the pump 37 is directly supplied to the tank 41.
And the steering assist force is not generated.

When steering is not performed, if the steering is performed rightward from the steering angle midpoint, the torsion bar 3 is twisted by a torque corresponding to the steering force, and the two valve members 24 and 25 rotate relatively. As a result, the opening degree of the throttle portion A between each right steering recess 27 and each pressure oil supply recess 29 and the throttle portion B between each left steering recess 28 and each pressure oil discharge recess 30 are formed. The opening degree increases, and the opening degree of the throttle portion C between each left steering recess 28 and each pressure oil supply recess 29 and the throttle between each right steering recess 27 and each pressure oil discharge recess 30. The opening degree of the portion D is reduced. As a result, the first oil chamber 21
High pressure oil having a pressure corresponding to the steering force is supplied to the second oil chamber 2
The low-pressure oil is recirculated from the tank 2 to the tank 41, and a steering assist force to the right of the vehicle acts on the rack 8.

If steering is not performed and steering is performed to the left from the steering angle midpoint, the degree of opening of each of the throttle portions A, B, C, and D changes in reverse to that when steering is performed to the right. A steering assist force to the left of the vehicle acts on the rack 8.

As shown in FIG. 3, the steering suppressing mechanism 50
Is in an oil passage between the second oil chamber 22 and the control valve 23,
It has a first flow control valve 51 for suppressing right steering, a first check valve 61 functioning as a first regulating valve, and a first modified steering permission mechanism 66 of the present invention. A second flow control valve 52 for suppressing left steering in an oil passage between
And a second check valve 62 functioning as a second regulating valve, and a second modified steering permission mechanism 67 of the present invention.

The flow control valves 51 and 52 are connected to the housing 5
3, a valve member 55 housed in a valve chamber 54 in the housing 53, a solenoid 57, and a compression coil spring 58 housed in a spring chamber 56 in the housing 53. A spring receiving portion 56a arranged in the spring chamber 56 is formed integrally with the valve member 55. The valve member 55
In the normal state in which the steering is not suppressed, the spring is arranged upward in the figure by the elasticity of the spring 58, and is displaced downward in the figure when the solenoid 57 is excited. First flow control valve 51
The valve chamber 54 is connected to the left steering recess 28 of the control valve 23, and the spring chamber 56 is connected to the second oil chamber 22. The valve chamber 54 of the second flow control valve 52 is provided with the right steering recess 27 of the control valve 23.
, And the spring chamber 56 is connected to the first oil chamber 21.
Valve chamber 54 and spring chamber 56 in each flow control valve 51, 52
A narrowing portion 59 is provided between them. The degree of opening of each throttle section 59 is
In the normal state, the valve member 55 is fully opened to allow the flow of the pressure oil for generating the steering assist force without restricting the flow rate, and becomes smaller in accordance with the amount of downward movement of the valve member 55 in the drawing.

Each of the check valves 61 and 62 includes a housing 63
And a first connection port 63a formed in the housing 63.
, A spring 65 for urging the valve member 64 in the closing direction of the first connection port 63a, and a normally open second connection port 63b formed in the housing 63. The first check valve 61 is connected in parallel to the first flow control valve 51, the first connection port 63a is connected to the left steering recess 28 of the control valve 23, and the second connection port 63b is connected to the second oil chamber. 22
Connected to. The second check valve 62 includes a second flow control valve 52.
Are connected in parallel, and the first connection port 63a is connected to the control valve 23.
The second connection port 63b is connected to the first oil chamber 21. Thereby, the first check valve 61
Allows the flow of pressure oil for generating left steering assist force without restricting the flow rate, and regulates the flow of pressure oil for generating right steering assist force. The second check valve 62 allows the flow of pressure oil for generating the right steering assist force without restricting the flow rate, and regulates the flow of the pressure oil for generating the left steering assist force.
In each of the check valves 61 and 62, the hydraulic pressure required to move the valve member 64 against the elasticity of the spring 65 to open the first connection port 63a and allow the flow of the pressure oil becomes the cracking pressure. .

Each of the correction steering permission mechanisms 66 and 67 has a cylinder 68, a piston 69 that can reciprocate within a predetermined stroke within the cylinder 68, and a spring 70 that applies a pressure to push the piston 69 in one direction. However, the pressure is set smaller than the cracking pressure of each of the check valves 61 and 62. The interior of each cylinder 68 has a first pressure oil holding chamber 68 a and a second pressure oil holding chamber 68
The first pressure oil holding chamber 68a is minimized by the piston 69 being urged by the elastic force of the spring 70 in the normal state.

The first modified steering permission mechanism 66 is connected in parallel to the first flow control valve 51 and the first check valve 61, and the first pressure oil holding chamber 68 a is provided with the left steering recess of the control valve 23. 2
8 and the second pressure oil holding chamber 68 b is connected to the second oil chamber 22. The second correction steering permission mechanism 67 is connected in parallel to the second flow control valve 52 and the second check valve 62, and the first pressure oil holding chamber 68a is connected to the right steering recess 2 of the control valve 23.
7 and the second pressure oil holding chamber 68 b is connected to the first oil chamber 21.

In the first modified steering permission mechanism 66,
The pressure oil for generating the left steering assist force is supplied to the first pressure oil holding chamber 68a.
, The piston 69 can be moved in one direction (downward in the figure) by a set stroke against the pressure applied by the spring 70. The set stroke is determined according to the steering angle in the play range of the steering wheel in the case of straight running or cornering at a constant steering angle. The steering angle in the play range can be set arbitrarily. As a result, the pressure oil in the second pressure oil holding chamber 68b is discharged to the second oil chamber 22 side, so that only the set volume corresponding to the set stroke of the piston 69 is used to generate the left steering assist force. Flow is allowed without flow restriction. Since the pressure for pushing the piston 69 in one direction is set to be smaller than the cracking pressure of the first check valve 61, the flow of the pressure oil for generating the left steering assist force is permitted by the first check valve 61. Takes precedence over The second pressurized oil holding chamber 68b
The pressure oil discharged to the second oil chamber 22 side is introduced into the second pressure oil holding chamber 68b again, so that the piston 69 moves in the other direction (upward in the figure). As a result, only the volume of the pressure oil for generating the left steering assist force allowing the flow is allowed without restricting the flow rate of the flow of the pressure oil for generating the right steering assist force.

In the second modified steering permission mechanism 67,
The pressure oil for generating the right steering assist force is supplied to the first pressure oil holding chamber 68a.
, The piston 69 can be moved in one direction (downward in the figure) by a set stroke against the pressure applied by the spring 70. The set stroke is determined according to the steering angle in the play range of the steering wheel in the case of straight running or cornering at a constant steering angle. As a result, the pressure oil in the second pressure oil holding chamber 68b is discharged to the first oil chamber 21 side, so that only the set volume corresponding to the set stroke of the piston 69 is supplied to the pressure oil for generating the right steering assist force. Flow is allowed without flow restriction. Since the pressure for pushing the piston 69 in one direction is set smaller than the cracking pressure of the second check valve 62, the flow of the pressure oil for generating the right steering assist force is permitted by the second check valve 62.
Takes precedence over The pressurized oil discharged from the second pressurized oil holding chamber 68b to the first oil chamber 21 due to the allowable flow of the pressurized oil is
By being introduced again into the pressure oil holding chamber 68b, the piston 6
9 moves in the other direction (upward in the figure). As a result, only the volume of the pressure oil for generating the right steering assist force allowing the flow is allowed without restricting the flow rate of the flow of the pressure oil for generating the left steering assist force.

Each solenoid 57 is connected to a control device 71. A plurality of right obstacle detection sensors 73 and 74 and left obstacle detection sensors 75 and 76 attached to the vehicle 72 are connected to the control device 71. The obstacle detection sensors 73, 74, 75, and 76 detect, for example, obstacles on the left and right sides and the left and right rear sides of the vehicle 72, and include a transmitter that emits a radar wave such as an ultrasonic wave from the vehicle. And a receiver for receiving the reflected wave of the radar wave from the obstacle, and sends the received radar wave to the control device 71 as a detection signal of an obstacle that may collide. The control device 71 transmits the solenoid drive current obtained by amplifying the obstacle detection signals from the right obstacle detection sensors 73 and 74 to the solenoid 57 of the first flow control valve 51 as a right steering suppression signal, and detects the left obstacle. The solenoid drive current obtained by amplifying the obstacle detection signals from the sensors 75 and 76 is transmitted to the solenoid 57 of the second flow control valve 52 as a left steering suppression signal.

The pipe between the pump 37 and the control valve 23 communicates with the tank 41 via a relief valve 83 for protecting the pump 37 and a check valve 84 for preventing air bubbles from entering due to surging.

According to the above configuration, the obstacle detection sensor 7
When there is no obstacle detection signal from 3, 74, 75, 76, at the time of right steering, the control valve 23 guides the pressure oil to the first oil chamber 21 through the throttle portion 59 of the second flow control valve 52, Second
By guiding the pressure oil from the oil chamber 22 to the tank 41 via the throttle portion 59 of the first flow control valve 51, a steering assist force in the right steering direction can be applied. During left steering, the control valve 23 guides pressure oil to the second oil chamber 22 through the throttle portion 59 of the first flow control valve 51, and pressurizes oil from the first oil chamber 21 to the second oil chamber 22.
By guiding the flow control valve 52 to the tank 41 through the throttle portion 59, a steering assist force in the left steering direction can be applied.

When the right obstacle detection sensors 73 and 74 detect an obstacle and the obstacle detection signal is input to the control device 71, the control device 71 outputs a right steering suppression signal to the solenoid of the first flow control valve 51. 57 and the solenoid 57
To excite. Due to the excitation, as shown in FIG.
The valve member 55 of the flow control valve 51 moves downward in the drawing, and the opening of the throttle portion 59 decreases. That is, during right steering, the second
The first flow control valve 51 is driven such that the pressure oil flow for generating the right steering assist force from the oil chamber 22 to the tank 41 decreases. At this time, the opening of the throttle portion 59 does not have to be in the fully closed state. Further, the first check valve 61 regulates the flow of the pressure oil for generating the right steering assist force. Further, the first modified steering permitting mechanism 66 permits only the volume of the pressure oil for generating the left steering assist force allowing the flow without restricting the flow of the pressure oil for generating the right steering assist force. Therefore, the flow of the pressure oil for generating the right steering assist force is restricted unless the left steering is performed. As a result, the movement of the hydraulic cylinder 18 is suppressed, and a right steering suppression force is generated. When the right steering suppression signal is released, the first flow control valve 51
The valve member 55 moves in the direction to increase the opening of the throttle portion 59 by the elastic force of the spring 58, and the suppression of the right steering is released.

When the left obstacle detection sensors 75 and 76 detect an obstacle and the obstacle detection signal is input to the control device 71, the control device 71 outputs the left steering suppression signal to the solenoid of the second flow control valve 52. 57 and the solenoid 57
To excite. By the excitation, the valve member 55 of the second flow control valve 52 moves downward in the figure, and the opening degree of the throttle portion 59 decreases. That is, the second flow control valve 52 is driven so that the pressure oil flow for generating the left steering assist force from the first oil chamber 21 to the tank 41 during the left steering is reduced. In addition,
At this time, the opening degree of the throttle portion 59 does not need to be in the fully closed state.
In addition, the second check valve 62 regulates the flow of pressure oil for generating the left steering assist force. Further, the second modified steering permission mechanism 67
Only allows the volume of the pressure oil for generating the right steering assist force to allow the flow without restricting the flow rate of the flow of the pressure oil for generating the left steering assist force. Unless otherwise, the flow of pressure oil for generating the left steering assist force is restricted. As a result, the movement of the hydraulic cylinder 18 is suppressed, and a left steering suppression force is generated. When the left steering suppression signal is released, the valve member 55 of the second flow control valve 52 moves in a direction to increase the opening degree of the throttle portion 59 by the elasticity of the spring 58, and the suppression of the left steering is released.

When the steering in the left direction is performed in a state where the right steering suppression signal is generated and the left steering suppression signal is not generated, the first check valve 61 is connected between the second oil chamber 22 and the control valve 23. In this case, since the flow of the pressure oil for generating the left steering assist force is allowed without restricting the flow rate, the suppression force for the left steering is not generated. Further, when steering in the right direction is performed in a state where the left steering suppression signal is generated and the right steering suppression signal is not generated, the second check valve 62 is connected to the first oil chamber 21 and the control valve 2.
3, the flow of the pressure oil for generating the right steering assist force is permitted without restricting the flow rate, so that the right steering suppression force is not generated. This makes it possible to suppress the steering only in the steering direction in which there is a possibility of collision with an obstacle with a simple configuration without using a dedicated actuator. Also, without performing control such as switching the direction in which the steering suppression force is applied in accordance with the possibility of collision with an obstacle in the steering direction, simply outputting the steering suppression signal in response to the obstacle detection signal, Steering suppression can be performed only in the steering direction in which there is a possibility of collision with an obstacle. Thereby, the control device 71 for outputting the steering suppression signal uses the solenoid drive current obtained by amplifying the obstacle detection signal as the steering suppression signal, and the sensors 73, 74, 75, and 7 that detect the obstacle.
It is sufficient to output to the solenoid 57 corresponding to No. 6 and the configuration can be simplified.

At first, when the steering in the left direction is performed in a state where the right steering suppression signal is generated and the left steering suppression signal is not generated, the first modified steering permission mechanism 66 has priority over the first check valve 61. Therefore, the flow of the pressure oil for generating the left steering assist force is allowed without limiting the flow rate only for the set volume. That is, the piston 69 moves in one direction by the set stroke by a pressure smaller than the cracking pressure of the first check valve 61,
The pressure oil in the second pressure oil holding chamber 68b of the cylinder 68 is discharged to the second oil chamber 22 side by the volume indicated by hatching in FIG. 4, so that only the set volume corresponding to the set stroke of the piston 69 is left steered. The flow of the pressure oil for generating the auxiliary force is allowed without the flow rate being restricted. This allows
When the right steering is performed after the left steering, the piston 69 moves in the other direction by an amount corresponding to the volume of the pressure oil for generating the left steering assist force that allows the flow, so that the right steering assist force is generated. The flow of pressurized oil is allowed without flow rate limitation. Since the maximum value of the volume of the pressure oil for generating the right steering assist force that allows the flow is the set volume corresponding to the steering angle in the play range, the right correction steering after the left steering can be performed.

At the beginning of rightward steering in a state where the left steering suppression signal is generated and the right steering suppression signal is not generated, the second modified steering permission mechanism 67 has priority over the second check valve 62. Therefore, the flow of the pressure oil for generating the right steering assist force is allowed without limiting the flow rate only for the set volume. That is, the piston 69 moves in one direction by the set stroke by a pressure smaller than the cracking pressure of the second check valve 62,
The pressure oil in the second pressure oil holding chamber 68b of the cylinder 68 is discharged to the first oil chamber 21 side, so that only the set volume corresponding to the set stroke of the piston 69 is used as the pressure oil for generating the right steering assist force. Flow is allowed without flow rate limitation. Accordingly, when the left steering is performed after the right steering, the piston 69 moves in the other direction by an amount corresponding to the volume of the pressure oil for generating the right steering assistance force that allows the flow, thereby generating the left steering assistance force. The flow of pressurized oil is allowed without flow rate limitation. Since the maximum value of the volume of the pressure oil for generating the left steering assist force that allows the flow is the set volume corresponding to the steering angle in the play range, the left correction steering after the right steering can be performed.

The provision of the corrective steering permission mechanisms 66 and 67 can prevent the vehicle from deviating from the intended traveling direction. For example, the hydraulic power steering device of the above embodiment, and the modified steering allowance mechanism 66 from this embodiment,
A comparison is made with the hydraulic power steering apparatus of the comparative example of FIG. Here, as shown in (1) of FIG. 6, consider a case where an obstacle P exists to the right of the vehicle M traveling straight. Also, as shown in (2) of FIG. 6, at time t1, an obstacle P is detected, right steering is suppressed, and at time t1,
It is assumed that the obstacle P goes out of the detection area in 2 and the steering suppression is released. In this case, as shown in (3) of FIG. 6, in both the comparative example and the embodiment, the steering wheel can be steered in the range of the play (± θ) until the steering is suppressed. When the obstacle P is detected and the right steering is suppressed, in the comparative example, after the steering is performed to the left by the play amount, the corrective steering to the right to eliminate the play amount cannot be performed. Therefore, as indicated by a broken line in (3) of FIG. 6, the steering angle to the left exceeds the play range until the right steering suppression is released. Therefore, as shown by the broken line R in (1) of FIG. 6, the vehicle M travels to the left from the intended direction until the obstacle P disappears and the steering suppression is released, and only after the steering suppression is released. Because you can return to the original course, it will meander. On the other hand, according to the above-described embodiment, even if the obstacle P is detected and the right steering is suppressed, after the steering is performed to the left by the play amount,
Corrective steering to the right to eliminate the play amount can be performed. Therefore, as shown by the solid line in (3) of FIG. 6, the steering angle to the left does not exceed the play range. Therefore, as shown by the solid line S in FIG. 6A, the vehicle M does not deviate from the traveling direction even when the right steering is suppressed.

FIG. 7 shows a second embodiment of the present invention. The difference from the first embodiment is that a different steering suppression mechanism 50 'is used.
The point is to have. The same parts as those in the first embodiment are denoted by the same reference numerals. That is, in the oil passage between the first oil chamber 21 and the control valve 23, the first flow control valve 5 for suppressing right steering is provided.
1 ', the first regulating valve 61', and the first modified steering permission mechanism 6
6, in the oil passage between the second oil chamber 22 and the control valve 23, a second flow control valve 52 'for suppressing left steering and a second flow control valve 52'.
It has a restriction valve 62 ′ and a second modified steering permission mechanism 67.

Each flow control valve 51 ', 52' and each regulating valve 6
1 'and 62' share the housing 53 'and the valve member 55'. That is, the housing 53 'includes a valve chamber 55' containing the valve member 55 'and the first spring 65'.
A spring chamber 56 'containing a second spring 58' for urging the spool 60 '. A solenoid 57 is provided around the spring chamber 56'. The second spring 58 'has a greater elasticity acting on the valve member 55' than the first spring 65 ',
As a result, the valve member 55 'is disposed in the upper part of the drawing in the normal state, and is displaced downward in the drawing when the solenoid 57 is excited. The valve chamber 54 'of the first flow control valve 51' and the first regulating valve 61 'is connected to the right steering recess 27 of the control valve 23, and the spring chamber 56' is connected to the first oil chamber 21. The valve chamber 54 'of the second flow control valve 52' and the second regulating valve 62 'is connected to the left steering concave portion 28 of the control valve 23, and the spring chamber 56'
Is connected to the second oil chamber 22. Each valve chamber 54 'and spring chamber 5
A narrowing portion 59 'is formed between the portion and the portion 6'. In the normal state, the opening degree of each throttle portion 59 'is fully opened to allow the flow of the pressure oil for generating the steering assist force without restricting the flow rate, and is reduced by the downward movement of the valve member 55' in the figure. Become. Accordingly, in the right steering suppression state in which the opening degree of the throttle portion 59 'is small, the first regulating valve 61' allows the flow of the pressure oil for generating the left steering assist force without restricting the flow rate, and performs the right steering. Regulates the flow of pressure oil for generating auxiliary force. Also, the second
The restriction valve 62 ′ allows the flow of pressure oil for generating the right steering assist force without restricting the flow rate in the left steering suppression state in which the opening degree of the throttle portion 59 ′ becomes small, and generates the left steering assist force. Regulate the flow of pressurized oil. Each control valve 61 ', 6
2 ', the valve member 5 is opposed to the elasticity of the first spring 65'.
5 'is moved to increase the opening degree of the throttle portion 59', and the hydraulic pressure required to allow the flow of the pressure oil without restricting the flow rate becomes the cracking pressure.

The first pressure oil holding chamber 68a of the first correction steering permission mechanism 66 is connected to the first oil chamber 21, and the second pressure oil holding chamber 68b is connected to the right steering recess 27 of the control valve 23. .
Further, the first pressure oil holding chamber 68 of the second correction steering permission mechanism 67
a is connected to the second oil chamber 22, and the second pressure oil holding chamber 68b is connected to the left steering recess 28 of the control valve 23. The other configuration is the same as that of the first embodiment.

According to the second embodiment, when the right obstacle detection sensors 73 and 74 detect an obstacle and the obstacle detection signal is input to the control device 71, the control device 71 transmits the right steering suppression signal. To the solenoid 57 of the first flow control valve 51 '.
To excite the solenoid 57. The excitation causes the first flow control valve 5 to move with the movement of the spool 60 '.
The 1 'valve member 55' moves downward in the figure, and the throttle portion 59 '
Becomes smaller. That is, the first oil chamber 2
The first flow control valve 51 'is driven so that the pressure oil flow for generating the right steering assist force toward 1 decreases. In addition,
At this time, the opening degree of the throttle portion 59 'may not be in the fully closed state. Further, the first regulating valve 61 'regulates the flow of the pressure oil for generating the right steering assist force. Further, the first modified steering permitting mechanism 66 permits only the volume of the pressure oil for generating the left steering assist force while permitting the flow without restricting the flow rate of the pressure oil for generating the right steering assist force. Therefore, the flow of the pressure oil for generating the right steering assist force is restricted unless the left steering is performed. As a result, the movement of the hydraulic cylinder 18 is suppressed, and a right steering suppression force is generated. When the right steering suppression signal is released, the valve member 5 of the first flow control valve 51 'is released.
5 'moves in the direction to increase the opening of the throttle portion 59' by the elastic force of the spring 58 ', and the suppression of the right steering is released.

When the left obstacle detection sensors 75 and 76 detect an obstacle and the obstacle detection signal is input to the control device 71, the control device 71 outputs a left steering suppression signal to the second flow control valve 52 '. The transmission to the solenoid 57 and the solenoid 5
7 is excited. Due to the excitation, the valve member 55 'of the second flow control valve 52' moves downward in the drawing as the spool 60 'moves, and the opening of the throttle portion 59' decreases. That is, the second flow control valve 5 is controlled so that the pressure oil flow rate for generating the left steering assist force toward the second oil chamber 22 decreases during left steering.
2 'is driven. At this time, the opening degree of the throttle portion 59 'may not be in the fully closed state. Further, the second regulating valve 62 'regulates the flow of the pressure oil for generating the left steering assist force. Further, the second modified steering permitting mechanism 67 permits only the volume of the pressure oil for generating the right steering assist force allowing the flow without restricting the flow rate of the pressure oil for generating the left steering assist force. Therefore, the flow of the pressure oil for generating the left steering assist force is restricted unless the right steering is performed. As a result, the movement of the hydraulic cylinder 18 is suppressed, and a left steering suppression force is generated. When the left steering suppression signal is released, the valve member 55 'of the second flow control valve 52' moves in a direction to increase the opening of the throttle portion 59 'due to the elasticity of the spring 58', and the suppression of left steering is suppressed. It is released.

When steering to the left is performed in a state where the right steering suppression signal is generated and the left steering suppression signal is not generated, the first regulating valve 61 ′ is connected between the first oil chamber 21 and the control valve 23. In this case, since the flow of the pressure oil for generating the left steering assist force is allowed without restricting the flow rate, the suppression force for the left steering is not generated. Further, when steering in the right direction is performed in a state where the left steering suppression signal is generated and the right steering suppression signal is not generated, the second regulating valve 62 ′ moves between the second oil chamber 22 and the control valve 23. Since the flow of the pressure oil for generating the right steering assist force is permitted without restricting the flow rate, the suppressing force for the right steering is not generated. This makes it possible to suppress the steering only in the steering direction in which there is a possibility of collision with an obstacle with a simple configuration without using a dedicated actuator.

When steering to the left is performed in the state where the right steering suppression signal is generated and the left steering suppression signal is not generated, the first modified steering permitting mechanism 66 operates the first restriction valve 61 '.
The flow of the pressure oil for generating the left steering assist force is permitted without limiting the flow rate only for the set volume. That is,
The piston 69 moves in one direction (upward in the figure) by a set stroke by a pressure smaller than the cracking pressure of the first regulating valve 61 ′, and the pressure oil in the first oil chamber 21 is moved to the first pressure oil holding chamber 68 a of the cylinder 68. By discharging to the side, only the set volume corresponding to the set stroke of the piston 69 allows the flow of the pressure oil for generating the left steering assist force without the flow rate being restricted. Thereby, when the right steering is performed after the left steering, the piston 69 moves in the other direction (downward in the figure) by an amount corresponding to the volume of the pressure oil for generating the left steering assist force allowing the flow, The flow of the pressure oil for generating the right steering assist force is allowed without being restricted in the flow rate.

When steering to the right is performed in a state where the left steering suppression signal is generated and the right steering suppression signal is not generated, the second modified steering permission mechanism 67 causes the second restriction valve 62 'to operate.
The flow of the pressure oil for generating the right steering assist force is permitted without limiting the flow rate only for the set volume. That is,
The piston 69 moves in one direction (upward in the figure) by a set stroke by a pressure smaller than the cracking pressure of the second regulating valve 62 ′, and the pressure oil in the second oil chamber 22 is moved to the first pressure oil holding chamber 68 a of the cylinder 68. By discharging to the side, only the set volume corresponding to the set stroke of the piston 69 allows the flow of the pressure oil for generating the right steering assist force without the flow rate being restricted. Accordingly, when the left steering is performed after the right steering, the piston 69 moves in the other direction (downward in the figure) by an amount corresponding to the volume of the pressure oil for generating the right steering assist force allowing the flow, The flow of the pressure oil for generating the left steering assist force is allowed without being limited. The other effects are the same as those of the first embodiment.

The present invention is not limited to the above embodiments. For example, the present invention may be applied to a hydraulic power steering apparatus other than the rack and pinion on type, for example, a ball screw type.

[0051]

According to the present invention, it is possible to suppress the steering only in the steering direction in which there is a possibility of collision with an obstacle with a simple configuration without using a dedicated actuator, and further, to the direction in which the steering is suppressed. And the hydraulic power steering apparatus capable of preventing the vehicle from deviating from the intended traveling direction.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a hydraulic power steering device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a configuration diagram of a hydraulic power steering device according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of the flow control valve according to the first embodiment of the present invention in a right steering suppression state;

FIG. 5 is a configuration diagram of a hydraulic power steering device of a comparative example.

6A is a diagram illustrating a relationship between a traveling direction of a vehicle and an obstacle, FIG. 6B is a diagram illustrating a relationship between a steering suppression signal and time,
(3) is a diagram showing the relationship between the steering angle and time.

FIG. 7 is a configuration diagram of a hydraulic power steering device according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rack-pinion type power steering device 18 Hydraulic cylinder 21 First oil chamber 22 Second oil chamber 23 Control valve 37 Pump 51, 51 'First flow control valve 52, 52' Second flow control valve 57 Solenoid 61, 61 ' 1 restriction valve 62, 62 'second restriction valve 66 first correction steering permission mechanism 67 second correction steering permission mechanism 68 cylinder 69 piston 71 control device 73, 74, 75, 76 obstacle detection sensor

Claims (2)

[Claims] 1. A hydraulic actuator having a first oil chamber for generating a right steering assist force and a second oil chamber for generating a left steering assist force, and guides pressure oil from a pump to the first oil chamber during right steering. A hydraulic power steering apparatus comprising: a control valve that guides pressure oil from a pump to a second oil chamber during left steering, wherein an obstacle that may collide in the right steering direction and an obstacle that may collide in the left steering direction. A first flow control valve for suppressing right steering disposed between one oil chamber and the control valve; and a left flow suppressing valve disposed between the other oil chamber and the control valve. Means for transmitting a right steering suppression signal based on the possibility of collision with an obstacle in the right steering direction and transmitting a left steering suppression signal based on the possibility of collision with an obstacle in the left steering direction. And the right steering assist signal by the right steering suppression signal The first flow control valve is driven so as to reduce the pressure oil flow for raw, and the second flow control valve is driven such that the pressure oil flow for generating the left steering assist force is reduced by the left steering suppression signal. Means, between one of the oil chambers and the control valve, allows the flow of the pressure oil for generating the left steering assist force without restricting the flow rate, and allows the flow of the pressure oil for generating the right steering assist force. Between the first regulating valve to regulate, the other oil chamber and the control valve, the flow of the pressure oil for generating the right steering assist force is allowed without restricting the flow rate, and the flow for the left steering assist force is generated. A second regulating valve for regulating the flow of pressure oil, a first regulating valve connected in parallel to the first flow control valve and the first regulating valve,
The flow of hydraulic oil for generating left steering assist force is permitted without limiting the flow rate only for the set volume, and the flow of hydraulic oil for generating right steering assist force is allowed only for the permitted volume in preference to the regulating valve. A first modified steering permitting mechanism that permits the flow without restricting the flow, a second flow control valve and a second regulating valve that are connected in parallel to each other,
The flow of hydraulic oil for generating the right steering assist force is permitted without limiting the flow rate only for the set volume in preference to the regulating valve, and the flow of the hydraulic oil for generating the left steering assist force is allowed only for the allowed volume. A hydraulic power steering apparatus comprising: a second correction steering permission mechanism that permits the flow without restricting the flow rate. Each correction steering permitting mechanism includes a cylinder, a piston reciprocally movable within a predetermined stroke within the cylinder, and a spring for applying a pressure for pushing the piston in one direction. The first hydraulic chamber is set to be smaller than the cracking pressure of the regulating valve, the first oil chamber is connected to the cylinder of one of the corrective steering permission mechanisms, and the second hydraulic chamber is connected to the cylinder of the other corrective steering permission mechanism. In the allowance mechanism, the piston can be moved in one direction by a set stroke against the pressure applied by the spring so that the flow of the pressure oil for generating the left steering assist force is allowed only in the set volume. The piston is movable in the other direction so that the flow of the pressure oil for generating the right steering assist force is allowed only in the allowed volume, and in the second modified steering allowance mechanism, The piston is allowed to move in one direction by a set stroke against the pressure applied by the spring so that the flow of the pressure oil for generating the right steering assist force is allowed only in the set volume, and the allowed 2. The hydraulic power steering apparatus according to claim 1, wherein the piston is movable in the other direction so that the flow of the pressure oil for generating the left steering assist force is permitted only for the volume integral.