JP3535638B2 - Vehicle steering system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering system that can be used to prevent a running vehicle from colliding with another vehicle or an obstacle such as a guardrail or from leaving the traveling lane. For example, in a hydraulic power steering device or an electric power steering device, when the vehicle and an obstacle are close to each other, the vehicle is prevented from being steered in the direction of the obstacle, or the vehicle is separated from the obstacle. In particular, the present invention relates to a device that can realize preventive safety such that steering assist force can be positively generated.

[0002]

2. Description of the Related Art As one of the dangerous states that can occur in a running vehicle, there is a case where the driver tries to change course without noticing the vehicle approaching diagonally from behind. The idea of preventing dangerous situations and accidents that may occur due to the steering operation by the driver's intention is ASV (Adva
nced Safety Vehicle) concept. However, how to specifically avoid a dangerous state that may occur due to a steering operation by the driver's intention, in particular, a technique that can realize the avoidance of the dangerous state by controlling a hydraulic power steering device or an electric power steering device is , Currently not materialized.

Therefore, the steering by the driver is suppressed for the purpose of preventing the vehicle from colliding with another vehicle or an obstacle such as a guardrail at the time of lane change or the like, or preventing the vehicle from moving out of the driving lane. There has been proposed a vehicle steering system including a means.

For example, Japanese Patent Laid-Open No. 291099/1990 detects the presence or absence of another vehicle on the side of the vehicle and the distance to the road shoulder, and the steering direction. Disclosed is a steering device that applies a steering suppression force when the distance is short.

Further, Japanese Patent Laid-Open No. 3-96439 discloses a steering angle, a gripping force of a steering wheel by a driver, and the like to determine whether or not there is an abnormality in the driver. If an abnormality is detected during steering, steering is suppressed. A steering device that applies force is disclosed.

Further, Japanese Patent Laid-Open No. 7-47967 discloses the presence or absence of an obstacle around the vehicle and the steering direction, judges the risk degree based on the detection result, and steers according to the danger degree. A steering device for suppressing is disclosed.

Further, Japanese Patent Laid-Open No. 19274/1992 discloses a hydraulic actuator having an oil chamber for generating a right steering assist force and an oil chamber for generating a left steering assist force, and a pump from one pump to one oil chamber depending on a steering direction. In a hydraulic power steering device including a control valve that supplies high-pressure oil and recirculates low-pressure oil from the other oil chamber to a tank, the presence or absence of an obstacle and the steering direction on the rear side of the vehicle are detected, and the detected steering is detected. Disclosed is that when there is an obstacle in the direction, the supply oil passage 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 so that the driver recognizes the existence of the obstacle.

Further, it has been proposed to suppress steering by cutting off an oil passage for supplying high-pressure oil to the hydraulic actuator or an oil passage for discharging low-pressure oil from the hydraulic actuator when an obstacle is detected.

[0009]

Since the conventional steering system detects an obstacle or the like that causes steering suppression and also detects the steering direction, the steering suppression force is applied.
It is necessary to determine the presence / absence of steering and the steering direction in order to determine whether or not to suppress the steering. Therefore, there is a problem that the control system becomes complicated.

In the conventional example in which the driver is made aware of the presence of an obstacle by canceling the application of the steering assist force, the steering assist force is small during high-speed traveling, and therefore it is not sufficient to suppress the steering simply by canceling the steering assist force. Therefore, it is difficult for the driver to recognize the existence of the obstacle. Further, since the steering force does not correspond to the magnitude of the steering restraint force, the steering restraint may be insufficient or excessive.

In the conventional example in which the high pressure oil supply oil passage to the hydraulic actuator is simply bypassed to the low pressure side, or the high pressure oil supply oil passage and the low pressure oil discharge oil passage to the hydraulic actuator are cut off, there is a possibility of collision with an obstacle. There is a problem that not only the steering in the certain steering direction but also the steering in the steering direction where there is no possibility of collision is suppressed. If the steering direction is detected and the direction in which the steering suppression force is applied is switched according to the possibility of collision with an obstacle in the detected steering direction, the steering can be suppressed only in the steering direction where there is a possibility of collision with the obstacle. Can be done, but the configuration of the control system becomes complicated.

Further, when the vehicle passes a curved road having a narrow vehicle width, there is a possibility that the vehicle deviates from the traveling road if the steering suppression control is performed. Furthermore, when it is not possible to determine whether the purpose of steering is to change lanes, enter a curved road, or avoid an obstacle ahead, steering suppression control is performed when entering a curved road or avoiding an obstacle ahead. May cause the vehicle to deviate from the road or collide with an obstacle ahead. In order to prevent this, when the degree of risk is determined and steering is suppressed as in the conventional example, the control system becomes extremely complicated and expensive.

Further, the present applicant has previously developed a method capable of safely controlling the electric power steering device by software when a dangerous state occurs and avoiding the dangerous state occurring in the vehicle. The method is as follows. As shown in FIG. 18, the electric power steering apparatus includes a steering control unit 53 including a motor 531 for generating a steering assist force and a CPU 532 for controlling a drive current given to the motor 531.
3 and 3 are provided. Then, in the normal control state, the steering control unit 533 determines the motor current value based on the torque voltage T _V and the vehicle speed signal from the torque sensor indicating that the steering wheel has been operated, and outputs the current value to the motor 531. give. In this case, the CPU 532 included in the steering control unit 533 calculates the motor current value from the input torque voltage T _V and vehicle speed signal according to a predetermined program.

In addition to the above structure, a danger detection sensor 536 and a danger judgment CPU 537 are provided. The danger detection sensor 536 can be configured by, for example, an infrared sensor or the like which is arranged at both left and right corners of the front and rear of the vehicle and outputs a signal when the four corners of the vehicle approach an obstacle. The risk determination CPU 537 determines in which direction of the vehicle the obstacle is approaching based on the signal from the danger detection sensor 536, and control necessary for avoiding contact of the vehicle with the obstacle. A signal is generated and provided to the steering control unit 533. In the steering control unit 533, when a signal from the risk determination CPU 537 is given, the motor current value calculated by the CPU 532 is rewritten based on the signal, and the motor 531 is controlled by the rewritten motor current value. ing.

However, in the configuration shown in FIG.
In addition to the above-mentioned problem that the control system becomes complicated because it is necessary to determine the steering direction, if an existing power steering device is to be retrofitted with a control mechanism for avoiding a dangerous state, the existing electric power steering system may be used. There are problems that the steering control unit 533 provided in the device must be greatly improved and that retrofitting is difficult. This is because when an attempt is made to give the signal from the CPU 537 for risk determination to the existing steering control unit 533, the existing steering control unit 533 is provided with an input port for receiving the signal from the CPU 537 for risk determination. Must be If there is no input port, the risk control C
The signal from PU537 cannot be given. Also,
The CPU 532 of the steering control unit 533 is the risk determination C
In order to rewrite the motor current value to a different current value based on the signal from the PU 537, it is necessary to change the arithmetic program of the CPU 532.

Therefore, in order to manufacture the electric power steering apparatus having the above-mentioned structure, the existing steering control unit 53 is used.
No. 3 could not be used as it was, and the steering control unit had to be newly manufactured, or the existing steering control unit 533 had to be significantly improved (rewriting of the CPU program, etc.). Based on such a background, the steering control unit provided in the existing electric power steering device can be used as it is, and it can be manufactured at low cost, and can be retrofitted to the existing electric power steering device. It is desired to provide an electric power steering device having a control function.

An object of the present invention is to provide a vehicle steering system that can solve the above problems.

[0018]

SUMMARY OF THE INVENTION The present invention provides a vehicle steering system including means for suppressing steering by a driver, in a state in which a steering suppression force can be applied and a state in which the steering suppression force can be released regardless of the presence or absence of steering. It is characterized by being switched to and. According to the configuration of the present invention, it is not necessary to determine the presence or absence of steering and the direction in order to determine whether or not to suppress steering, and the control system can be simplified.

The steering restraining force applied by the vehicle steering system according to the present invention is preferably set according to the steering force. As a result, appropriate steering control can be performed without complicating the control system.

The steering apparatus for a vehicle according to the present invention comprises means for detecting the cause of steering restraint in the right steering direction and means for detecting the cause of steering restraint in the left steering direction. It is preferable to be able to switch to a state in which the steering suppression force can be applied only to this. As a result, the steering restraining force can be applied only to steering in the direction in which the steering restraining is required without performing control for switching the acting direction of the steering restraining force according to the steering direction, and the control system can be simplified.

In the vehicle steering system of the present invention, it is preferable that the vehicle steering device is provided with a means for detecting the vehicle speed, and the steering control force can be released when the vehicle speed is equal to or lower than a preset value. Further, it is preferable that a means for detecting the deceleration operation is provided and the state can be switched to a state in which the application of the steering restraining force can be released when the deceleration operation is performed. This prevents the vehicle from passing through a curved road with a narrow vehicle width and avoiding obstacles in front of the vehicle. It is possible to prevent the vehicle from deviating from the vehicle and colliding with a front obstacle. When the vehicle speed is below the set value or when deceleration is performed, even if there is a possibility of a collision between the vehicle and an obstacle, the vehicle speed is low and the time margin for avoiding the collision is large, so steering is suppressed. There is no problem even if the control is released.

In the vehicle steering system of the present invention, it is preferable that the speed at which the steering restraining force is released is slowed according to the steering force. As a result, it is possible to prevent sudden turning due to the sudden release of the steering suppression force.

The vehicle steering system according to the present invention includes a hydraulic actuator having an oil chamber for generating a right steering assist force and an oil chamber for generating a left steering assist force, and one oil from a pump depending on a steering direction and a steering force. Control valve that guides high-pressure oil to the chamber and low-pressure oil from the other oil chamber to the tank, means for detecting the cause of steering suppression in the right steering direction, means for detecting the cause of steering suppression in the left steering direction, and right steering Means for transmitting a right steering restraint signal based on the detection of the steering restraint cause in the left steering direction and a left steering restraint signal based on the detection of the steering restraint cause in the left steering direction; It is preferable to provide a means capable of applying a steering restraining force by high-pressure oil according to the steering force via. By generating the steering restraining force by the high-pressure oil having a pressure corresponding to the steering force through the control valve, it is possible to appropriately restrain the steering without complicating the control system.

The steering device of the present invention guides high-pressure oil from the pump to one of the oil chambers in accordance with the steering direction, and a hydraulic actuator having a right steering assist force generating oil chamber and a left steering assist force generating oil chamber. In a hydraulic power steering system including a control valve for guiding low-pressure oil from the other oil chamber to the tank, a means for detecting an obstacle that may collide in the right steering direction and an obstacle that may collide in the left steering direction. A means for detecting an object, a right flow control valve for steering suppression which is arranged in an oil passage between the hydraulic actuator and the control valve, and a left arranged in an oil passage between the hydraulic actuator and the control valve. Based on the possibility of collision between the flow control valve for steering suppression and the obstacle in the right steering direction, a right steering suppression signal is transmitted and the left steering suppression signal is generated based on the possibility of collision with the obstacle in the left steering direction. Means for driving a flow control valve for suppressing right steering so that the pressure oil flow rate for generating the right steering assist force is reduced by the right steering suppression signal, and left steering is controlled by the left steering suppression signal. And a means for driving a flow control valve for suppressing left steering so that the flow rate of pressure oil for generating the assisting force is reduced. It is preferable that the oil flow rate is not reduced, and the left steering control flow rate control valve does not reduce the pressure oil flow rate for generating the right steering assist force. Sends a right steering suppression signal based on the detection of the steering suppression cause in the right steering direction,
By driving one of the flow control valves for the right steering suppression by the right steering suppression signal, the pressure oil flow rate for generating the right steering assist force between each oil chamber of the hydraulic actuator and the control valve is reduced. As a result, the movement of the hydraulic actuator is suppressed, and the right steering suppression force is generated. When the right steering suppression signal is generated, the one flow control valve does not reduce the pressure oil flow rate for generating the left steering assist force between each oil chamber and the control valve. No restraint force for left steering is generated. In addition, by transmitting a left steering suppression signal based on detection of the steering suppression cause in the left steering direction, and driving the other flow control valve for left steering suppression by the left steering suppression signal, The pressure oil flow rate for generating the left steering assist force between the control valve and the control valve is reduced. As a result, the movement of the hydraulic actuator is suppressed and a left steering suppression force is generated. While the left steering suppression signal is being generated, the other flow control valve does not reduce the pressure oil flow rate for generating the right steering assist force between each oil chamber and the control valve. No restraint force for right steering is generated. As a result, the steering can be suppressed only in the steering direction where there is a possibility of collision with an obstacle, with a simple configuration without using a dedicated actuator.

The right steering restraint signal is transmitted upon detection of an obstacle that may collide in the right steering direction, and the left steering restraint signal is transmitted upon detection of an obstacle that may collide in the left steering direction. preferable. As a result, a steering suppression signal for driving each flow rate control valve can be output corresponding to the detection signal for each obstacle. That is, without performing control such as switching the direction in which the steering suppression force is applied according to the possibility of collision with an obstacle in the steering direction, simply outputting the steering suppression signal in response to the obstacle detection signal, The steering can be suppressed only in the steering direction where there is a possibility of collision with the obstacle, and the configuration of the control device for outputting the steering suppression signal can be simplified.

The control valve can guide high-pressure oil having a pressure corresponding to the steering force to the hydraulic actuator, and each flow rate control valve causes the flow rate of the pressure oil for generating the steering assist force according to the pressure of the high-pressure oil. It is preferably possible to reduce Thereby, the steering assist force can be generated according to the steering force. In this case, each flow rate control valve can generate the steering restraining force according to the steering force by reducing the flow rate of the pressure oil for generating the steering assist force according to the pressure of the high pressure oil. Therefore, appropriate steering suppression can be performed without complicating the control system.

Each flow rate control valve has a pressure sensing chamber and a valve member that moves according to the hydraulic pressure in the pressure sensing chamber, and the drive means of each flow rate control valve has an oil passage switching valve and each switching The valve connects the pressure sensitive chamber to the high pressure side by the steering suppression signal, connects the pressure sensitive chamber to the low pressure side by releasing the steering suppression signal, and steers according to the amount of movement of the valve member according to the pressure of the pressure sensitive chamber. It is preferable to reduce the pressure oil flow rate for generating the assisting force.
As a result, it is possible to obtain the steering restraining force according to the steering force. Further, the steering suppression can be released by connecting the pressure sensitive chamber to the low pressure side of the control valve via the switching valve by releasing the steering suppression signal. That is, the steering can be suppressed and released according to the steering force only by the switching operation of the oil passage by the switching valve, and the configuration can be simplified.

When any of the flow control valves is driven,
Further, it is preferable to provide a means for returning the high pressure oil supplied to the driven flow rate control valve to the low pressure side when the pressure oil flow rate for generating the steering assist force becomes the minimum. The steering suppression force is maximized when each flow rate control valve is driven and the pressure oil flow rate for generating the steering assist force is minimized. In this case, by returning the high-pressure oil guided to each flow control valve to the low-pressure side, even if the driver applies a steering force despite the steering suppression, the hydraulic pressure exceeding the relief pressure of the pump is It does not act, and it is possible to prevent problems due to the action of excessive hydraulic pressure.

According to one aspect of the present invention, a motor that is coupled to a steering mechanism including a steering wheel to generate a steering assist force when steering by the steering wheel and a target control value corresponding to a given input signal are determined. Then, drive control means for driving the motor using the target control value, a sensor for detecting the running state of the vehicle and outputting a running state signal, and a danger prediction signal due to the approach of the vehicle and the obstacle. It is connected between the danger predicting means for outputting and the sensor and the danger predicting means and the drive control means, and in a state where the danger predicting signal is not given from the danger predicting means, the running state signal given from the sensor is directly controlled In the state where the danger prediction signal is given from the danger prediction means as an input signal to the means,
A safety control means for danger avoidance for changing the running state signal given from the sensor according to the content of the danger prediction signal and giving the changed running state signal as an input signal to the drive control means. To do. According to this invention,
A sensor that outputs a running state signal and a risk prediction means,
The drive control means is connected via safety control means. Therefore, the traveling state signal output from the sensor and the danger prediction signal output from the danger prediction means are first given to the safety control means. In the safety control means, when the danger prediction signal is not given from the danger prediction means, the running state signal given from the sensor is given as it is to the drive control means as an input signal. On the other hand, in a state where the danger prediction signal is given from the danger prediction means, the safety control means changes the running state signal given from the sensor according to the content of the danger prediction signal, and the changed running state signal is drive control means. As an input signal. Therefore, the steering control unit for the existing electric power steering device can be used as it is for the drive control means, and the safety control means changes the traveling state signal to a traveling state signal that can avoid the danger at the time of risk prediction. Just enough. As described above, according to the present invention, it is possible to configure the electric power steering apparatus capable of performing the dangerous state avoidance control by using the existing drive control means (steering control unit) as it is. In another aspect of the present invention, in the above-described device, the danger prediction signal includes a signal indicating in which direction of the vehicle the obstacle is approaching, and the safety control means includes:
It is characterized in that the running condition signal given from the sensor is changed to a running condition signal corresponding to a target control value for prohibiting the vehicle from proceeding toward the obstacle.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION A steering apparatus according to a first embodiment of the present invention will be described below with reference to FIGS.

The rack and pinion type hydraulic power steering system 1 shown in FIG. 1 comprises 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 is also connected to the output shaft 4 via serrations 6. A pinion 7 is formed on the output shaft 4, and a steering wheel (not shown) is connected to each end of a rack 8 that meshes with the pinion 7. The input shaft 2 is supported by the valve housing 10a via a bearing 9 and is supported by the output shaft 4 via a bush 11. The output shaft 4 is a bearing 12,
It is supported by the rack housing 10 b via 13.
Accordingly, 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. Oil seals 14 and 15 are provided between the input / output shafts 2 and 4 and the valve housing 10a. A support yoke 16 that supports the rack 8 is provided, and 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 composed of a rack housing 10b and a piston 2 which is integrated with the rack 8.
0, and has a right steering assist force generating oil chamber 21 and a left steering assist force generating oil chamber 22 partitioned by the piston 20.

Oil chambers 21 and 22 of the hydraulic cylinder 18
Is connected to the rotary hydraulic control valve 23 via a steering suppression mechanism 50 described later. The control valve 23 includes a tubular first valve member 24 and a second valve member 25 that is 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 integrally formed on the outer circumference of the input shaft 2.

As shown in FIG. 2, the first valve member 2 thereof
A plurality of recesses along the axial direction are formed in the inner circumference of No. 4 and the outer circumference of the second valve member 25 at equal intervals in the circumferential direction. The first
The recesses on the valve member side are located at equal intervals in the circumferential direction.
It is composed of one right steering recess 27 and four left steering recesses 28. The second valve member side concave portion is composed of four pressure oil supply concave portions 29 and four pressure oil discharge concave portions 30 which are located at equal intervals in the circumferential direction. Each right steering recess 27
And the left steering recesses 28 are alternately arranged in the circumferential direction, and the pressure oil supply recesses 29 and the pressure oil discharge recesses 30 are alternately arranged in the circumferential direction.

Each right steering recess 27 is formed by the first valve member 2
First flow path 31 and valve housing 1 formed in 4
From the first port 32 formed in 0a, the steering suppression mechanism 5
Oil chamber 2 for generating the right steering assist force of the hydraulic cylinder 18
Lead to 1. Each left steering recess 28 is formed by the first valve member 2
Second flow path 33 and valve housing 1 formed in
From the second port 34 formed in the steering suppression mechanism 5
Oil chamber 2 for generating left steering assist force of hydraulic cylinder 18
Go to 2. Each pressure oil supply recess 29 communicates with a pump 37 as shown in FIG. 1 from a third flow passage 35 formed in the first valve member 24 and an inlet port 36 formed in the valve housing 10a. 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. It communicates with the tank 41 through the second discharge passage 39 and the discharge port 40 formed in the valve housing 10a. A relief valve (not shown) for protecting the pump 37 is provided.

When the steering is not restrained, the pump 37, the tank 41, and the oil chambers 21 and 22 of the hydraulic cylinder 18 have the first valve member 24 and the second valve member 2 respectively.
5 communicates with each other through the inter-valve flow path 42 between the inner and outer circumferences. 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 throttle portions A, B, C, D whose opening degree is changed by relative rotation of both valve members 24, 25. , The hydraulic cylinder 1 by changing the opening degree of the throttle portions A, B, C, D
The hydraulic pressure acting on 8 is controlled.

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

When the steering is not suppressed, when the steering wheel is steered to the right from the midpoint of the steering angle, the torsion bar 3 is twisted by the torque according to the steering force, and the valve members 24 and 25 are relatively rotated. As a result, the opening degree of the throttle portion A between each right steering recess portion 27 and each pressure oil supply recess portion 29 and the throttle portion B between each left steering recess portion 28 and each pressure oil discharge recess portion 30 are reduced. The opening degree becomes large, and the opening degree of the throttle portion C between each left steering recess portion 28 and each pressure oil supply recess portion 29 and the throttle portion between each right steering recess portion 27 and each pressure oil discharge recess portion 30. The opening degree of the portion D becomes smaller. As a result, the high-pressure oil having a pressure corresponding to the steering force is supplied from the pump 37 to the one oil chamber 21 of the hydraulic cylinder 18, and the low-pressure oil is circulated from the other oil chamber 22 of the hydraulic cylinder 18 to the tank 41. The steering assist force to the right acts on the rack 8.

When steering is not suppressed, steering to the left from the midpoint of the steering angle causes the apertures of the throttles A, B, C, and D to change oppositely to the case of steering to the right. The 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 provided.
Is a first flow rate control valve 51 for suppressing right steering, which is arranged in an oil passage between the oil chamber 21 for generating a right steering assist force of the hydraulic cylinder 18 and the rotary hydraulic control valve 23, and a left steering assist force generation. It has a second flow control valve 52 for suppressing left steering, which is arranged in an oil passage between the oil chamber 22 and the rotary hydraulic control valve 23. Each of the flow rate control valves 51, 52 is (1) in FIG.
As shown in (2) and (3), the housing 53, the valve chamber 54 formed in the housing 53, and the valve chamber 5 thereof.
4 has a valve member 55 incorporated therein, a pressure sensitive chamber 56 formed in the housing 53 thereof, a pressure sensitive member 57 incorporated in the pressure sensitive chamber 56 and a compression coil spring 58. The valve member 55 and the pressure sensitive member 57 are integrated, and normally the spring 5
It is arranged at the upper side in the figure by the elasticity of 8. The valve chamber 54 of the first flow control valve 51 is connected to the right steering recess 27 of the rotary hydraulic control valve 23 and the right steering assist force generating oil chamber 21 of the hydraulic cylinder 18 via an oil passage, and the second flow control is performed. Valve 5
The second valve chamber 54 is provided with a rotary hydraulic control valve 2 through an oil passage.
3 is connected to the left-hand steering concave portion 28 and the left-cylinder assisting force generating oil chamber 22 of the hydraulic cylinder 18. Each flow control valve 51, 5
2 has a throttle portion 59 that reduces the opening degree of the oil passage between the rotary hydraulic control valve 23 and the hydraulic cylinder 18 according to the amount of downward movement of the valve member 55 in the figure. Each throttle 59
Is normally fully open.

A first electromagnetic switching valve 61 is connected to the first flow control valve 51, and a second electromagnetic switching valve 62 is connected to the second flow control valve 52. Each switching valve 61, 62
Is a spool 63 that shares the housing 53 with the flow control valves 51 and 52, and is inserted into the housing 53 so as to be movable up and down in the figure, a compression coil spring 64 disposed below the spool 63, and a solenoid 65. Have and. Each spool 63 has a connecting oil passage 66 and a bypass oil passage 6
7 and are normally arranged at the upper side in the figure by the elastic force of the spring 64. As shown in (1) of FIG. 4, each of the switching valves 61 and 62 has the flow control valve 5 in a state in which the solenoid 65 is not excited and the spool 63 is located at the upper side in the drawing.
The pressure sensitive chambers 56 of 1, 52 are connected to the tank 41 on the low pressure side via the bypass oil passage 67. (2) and (3) of FIG.
As shown in FIG. 5, each switching valve 61, 62 connects the pressure sensing chamber 56 of the flow rate control valves 51, 52 via the communication oil passage 66 in a state where the solenoid 65 is excited and the spool 63 is displaced downward in the drawing. Connect to the valve chamber 54. As shown in (3) of FIG. 4, the solenoid 65 is excited to rotate the spool 63.
Is displaced downward in the figure, and the valve member 55 is displaced downward in the figure to fully close the throttle portions 59 of the flow rate control valves 51, 52, and the valve chamber 54 bypasses the pressure sensitive chamber 56. It is connected to the low pressure side tank 41 via the oil passage 67, and in the other states, the inlet of the bypass oil passage 67 is closed as shown in (1) and (2) of FIG.

As shown in FIG. 3, each switching valve 61, 6
The second solenoid 65 is connected to the control device 71.
The control device 71 has a plurality of right obstacle detection sensors 73 and 74 attached to the vehicle 72 for detecting the cause of steering suppression in the right steering direction, and an attachment to the vehicle 72 for detecting the cause of steering suppression in the left steering direction. The plurality of left obstacle detection sensors 75 and 76 are connected to each other. The obstacle detection sensors 73, 74, 75, 76 are mounted on the vehicle 72.
This is to detect obstacles on the left and right sides and the left and right rear sides of the vehicle as a cause for steering suppression, and a transmitter that emits radar waves such as ultrasonic waves from the vehicle and a receiver for reflected waves from the obstacles of the radar waves. 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 a solenoid drive current obtained by amplifying the obstacle detection signals from the right obstacle detection sensors 73 and 74 to the solenoid 65 of the first electromagnetic switching valve 61 as a right steering suppression signal to detect the left obstacle. The solenoid drive current obtained by amplifying the obstacle detection signals from the sensors 75 and 76 is
It transmits to the solenoid 65 of the electromagnetic switching valve 62.

According to the above construction, the steering restraining force is switched to the state in which the steering restraining force can be applied and the state in which the steering restraining force can be released regardless of the presence or absence of steering, and the steering restraining force depends on the steering force. The steering control force is switched to a state in which the steering control force can be applied only to the detected steering toward the steering control cause. That is, the obstacle detection sensors 73, 74, 75,
When there is no transmission of the above signal from 76, the rotary hydraulic control valve 23 controls the high pressure oil to move the high pressure oil to the first flow control valve 5 during the right steering.
1 from the valve chamber 54 through the throttle 59 to the hydraulic cylinder 18
To the right steering assist force generating oil chamber 21, and low pressure oil from the left steering assist force generating oil chamber 22 to the valve chamber 54 and the rotary hydraulic control valve 23 from the throttle portion 59 of the second flow control valve 52.
The steering assist force in the right steering direction can be applied by guiding the steering assist force to the tank 41 via. Further, during leftward steering, the rotary hydraulic control valve 23 causes the high-pressure oil to flow into the second flow rate control valve 5
From the second valve chamber 54 via the throttle 59.
To the left steering assist force generating oil chamber 22, and low pressure oil from the right steering assist force generating oil chamber 21 to the valve chamber 54 and the rotary hydraulic control valve 23 from the throttle portion 59 of the first flow control valve 51.
The steering assist force in the left steering direction can be applied by guiding it to the tank 41 via the.

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 electromagnetic switching valve 61. Sent to 65 and its solenoid 6
Excite 5 Due to the excitation, the spool 63 of the first electromagnetic switching valve 61 moves downward in the figure as shown in (2) of FIG. 4, and the pressure-sensitive chamber 56 of the first flow control valve 51 passes through the communication oil passage 66. It is connected to the valve chamber 54. As a result, the state can be switched to a state in which the steering suppression force can be applied only to the right steering. In this state, the valve chamber 54 of the first flow rate control valve 51 is controlled by the rotary hydraulic control valve 23 during right steering.
A part of the high-pressure oil guided to is guided to the pressure-sensitive chamber 56. The high-pressure oil guided to the pressure-sensitive chamber 56 causes the pressure-sensitive member 57 to move downward in the figure to a position where the hydraulic pressure of the high-pressure oil and the elastic force of the spring 58 balance each other. Along with the movement of the pressure sensitive member 57, the valve member 55 moves downward, and the opening degree of the throttle portion 59 decreases. That is, the first flow control valve 51 is arranged so that the pressure oil flow rate for generating the right steering assist force between the oil chamber 21 of the hydraulic cylinder 18 and the rotary hydraulic control valve 23 decreases.
Is driven. As a result, the movement of the hydraulic cylinder 18 is suppressed, and the right steering suppression force is generated. When the right steering suppression signal is released, the spool 63 of the first electromagnetic switching valve 61 moves upward in the figure by the elasticity of the spring 64, as shown in (1) of FIG. Pressure-sensitive chamber 56
Is connected to the low pressure side, the valve member 55 moves in the direction of increasing the opening degree of the throttle portion 59 by the elasticity of the spring 58,
It is possible to switch to a state where the application of the restraint force for the right steering can be released.

When the left obstacle detection sensors 75 and 76 detect an obstacle, the obstacle detection signal is input to the control device 71, and the control device 71 outputs the left steering suppression signal to the solenoid 65 of the second electromagnetic switching valve 62. , The solenoid 65 is excited. Due to the excitation, the steering control force can be applied only to the left steering in the same manner as when the right steering control signal is generated. In this state, the second flow rate control valve 52 is driven so that the pressure oil flow rate for generating the left steering assist force between the oil chamber 22 of the hydraulic cylinder 18 and the rotary hydraulic control valve 23 during left steering decreases. To be done. As a result, the movement of the hydraulic cylinder 18 is suppressed during left steering, and a left steering suppression force is generated. When the left steering suppression signal is released, the spool 63 of the second electromagnetic switching valve 62 moves upward in the figure due to the elasticity of the spring 64. Therefore, as in the case where the right steering suppression signal is released, left steering It is possible to switch to a state in which the application of the suppression force can be released.

When the vehicle is steered to the left while the right steering suppression signal is being generated, the rotary hydraulic control valve 23 causes the right steering assist force generating oil chamber 21 to move to the first flow rate control valve 51. Since the low-pressure oil is guided to the tank 41 via the valve chamber 54, the high-pressure oil is not guided to the pressure-sensitive chamber 56 of the first flow rate control valve 51. As a result, in the first flow control valve 51, the valve member 55 that moves together with the pressure sensitive member 57.
Moves due to the elasticity of the spring 58 in the direction of increasing the opening of the diaphragm 59. That is, the first flow control valve 51 is
The pressure oil flow rate for generating the left steering assist force between the oil chamber 22 of the hydraulic cylinder 18 and the rotary hydraulic control valve 23 is not reduced, and the left steering suppression force is not generated. Also, when the left steering suppression signal is generated,
When the steering to the right is performed, as in the case where the steering to the left is performed while the right steering suppression signal is being generated,
The second flow rate control valve 52 does not reduce the pressure oil flow rate for generating the right steering assist force between the oil chamber 21 of the hydraulic cylinder 18 and the rotary hydraulic control valve 23, and suppresses the right steering. It never happens. As a result, the steering can be suppressed only in the steering direction where there is a possibility of collision with an obstacle, with a simple configuration without using a dedicated actuator. Further, without performing control such as switching the direction in which the steering suppression force is applied according to the possibility of collision with an obstacle in the steering direction, only by outputting the steering suppression signal in response to the obstacle detection signal, It is possible to suppress steering only in the steering direction in which there is a possibility of collision with an obstacle. As a result, the control device 71 for outputting the steering restraint signal uses the solenoid drive current obtained by amplifying the obstacle detection signal as the steering restraint signal to detect the obstacles 73, 74, 75, 7.
Solenoid 6 of electromagnetic switching valves 61, 62 corresponding to 6
It is sufficient to output to 5, and the configuration can be simplified.

When the driver changes the steering force to the right from the state in which the right steering restraining force is generated, the rotary hydraulic control valve 23 senses as the valve chamber 54 according to the change in the steering force. The pressure of the high-pressure oil guided to the pressure chamber 56 is changed. The opening of the throttle portion 59 changes according to the change in the pressure of the high-pressure oil, the pressure oil flow rate for generating the right steering assist force changes, and the right steering restraining force changes. Further, when the driver changes the steering force to the left from the state where the left steering suppression force is generated, the left steering suppression force changes in the same manner as in the case of right steering. That is, it is possible to generate the steering restraining force according to the steering force, and thereby, appropriate steering restraining can be performed without complicating the control system.

As shown in (3) of FIG. 4, the driver increases the steering force in the right direction from the state where the right steering restraining force is generated, and the throttle portion 59 is fully closed to restrain the steering. When the force is maximized, the valve chamber 54 is connected to the tank 41 via the pressure sensing chamber 56 and the bypass oil passage 67, so that the high pressure oil guided to the first flow control valve 51 can be returned to the low pressure side. it can. Further, when the driver increases the steering force to the left from the state where the left steering restraining force is generated, and the throttle portion 59 is fully closed to maximize the steering restraining force, it is different from the case of right steering. Similarly, the high pressure oil guided to the second flow rate control valve 52 can be returned to the low pressure side. This allows
It is possible to prevent a problem from occurring due to the hydraulic pressure exceeding the relief pressure of the pump 37 acting when the driver applies the steering force despite the steering suppression.

Further, according to the above construction, the steering can be suppressed and released according to the steering force only by the switching operation of the electromagnetic switching valves 61 and 62, and the structure can be simplified.

FIG. 5 shows a second embodiment of the present invention. Only the differences from the first embodiment will be described, and the same parts are denoted by the same reference numerals. First, the first electromagnetic switching valve 61 causes the pressure sensitive chamber 56 of the second flow control valve 52 to move to the tank 41 on the low pressure side in a state where the application of the steering restraining force (not shown) in which the solenoid 65 is not excited can be released. Connecting. The second electromagnetic switching valve 62 sets the pressure sensing chamber 56 of the first flow rate control valve 51 to the low pressure side in the tank 4 in a state where the steering suppression force (not shown) in which the solenoid 65 is not excited can be released.
Connect to 1. Further, the first electromagnetic switching valve 61 is controlled by the second flow rate control in a state where the solenoid 65 is excited and the spool 63 moves from the state in which the steering restraining force can be released to be illustrated and the steering restraining force can be imparted. The pressure-sensitive chamber 56 of the valve 52 is connected to the valve chamber 54 of the first flow control valve 51.
In the second electromagnetic switching valve 62, the solenoid 65 is excited, and the spool 63 moves from the state in which the application of the steering suppression force can be released to the first flow control valve 51 in the state in which the steering suppression force can be applied. The pressure sensitive chamber 56 is connected to the valve chamber 54 of the second flow control valve 52. Other configurations are similar to those of the first embodiment.

According to the second embodiment, the solenoid 65 of the first electromagnetic switching valve 61 is generated when the right steering suppression signal is generated.
By the excitation of the pressure sensing chamber 56 of the second flow control valve 52,
Since it is connected to the valve chamber 54 of the flow control valve 51, the first
The second flow rate control valve 52 is provided through the valve chamber 54 of the flow rate control valve 51.
The high-pressure oil guided to the pressure-sensitive chamber 56 moves the pressure-sensitive member 57 of the second flow rate control valve 52 to a position where the hydraulic pressure of the high-pressure oil and the elastic force of the spring 58 balance each other. The pressure sensitive member 5
7, the valve member 55 of the second flow rate control valve 52 moves, and the opening degree of the throttle portion 59 of the second flow rate control valve 52 decreases. As a result, the pressure oil flow rate for generating the right steering assist force between the oil chambers 21 and 22 of the hydraulic cylinder 18 and the rotary hydraulic control valve 23 at the time of right steering is reduced.
Since the second flow rate control valve 51 is driven, it is possible to apply the right steering suppression force. Further, the solenoid 6 of the second electromagnetic switching valve 62 is activated when the left steering suppression signal is generated.
As the pressure sensitive chamber 56 of the first flow rate control valve 51 is connected to the valve chamber 54 of the second flow rate control valve 52 by the excitation of No. 5, the first flow rate is passed through the valve chamber 54 of the second flow rate control valve 52. Control valve 5
The high pressure oil introduced into the first pressure sensitive chamber 56 causes the pressure sensitive member 57 of the first flow control valve 51 to move the hydraulic pressure of the high pressure oil and the spring 58.
Move to a position where the elastic force of is balanced. Along with the movement of the pressure sensitive member 57, the valve member 55 of the first flow control valve 51
Moves, and the opening degree of the throttle portion 59 of the first flow control valve 51 decreases. As a result, the pressure oil flow rate for generating left steering assist force between the oil chambers 21 and 22 of the hydraulic cylinder 18 and the rotary hydraulic control valve 23 at the time of left steering is reduced, so that left steering is suppressed. Power can be applied. Other actions and effects are similar to those of the first embodiment.

FIG. 6 shows a third embodiment of the present invention. Only the differences from the first embodiment will be described, and the same parts are denoted by the same reference numerals. First, the valve member 55 and the pressure-sensitive member 57 are separate bodies, and the spring 82 that presses the valve member 55 against the pressure-sensitive member 57.
Is provided. In addition, each electromagnetic switching valve 61, 62
Is when the flow control valves 51 and 52 are being driven, and
There is no structure for connecting the valve chamber 54 of the flow rate control valves 51 and 52 to the low pressure side tank 41 when the pressure oil flow rate for generating the steering assist force is minimum. Other configurations are similar to those of the first embodiment.

According to the third embodiment, since the valve member 55 and the pressure sensitive member 57 are separated from each other, excessive stress acts on the connecting portion between the valve member 55 and the pressure sensitive member 57. It is possible to prevent a problem such as disconnection from occurring. When the driver increases the steering force from the state where the steering suppression force is generated, the relief valve 83 of the pump 37 can be opened to circulate the high pressure oil to the tank 41. Other actions and effects are similar to those of the first embodiment.

7 and 8 show a fourth embodiment of the present invention. Only the differences from the first embodiment will be described, and the same parts are denoted by the same reference numerals.

First, the steering restraint mechanism 50 'includes a first flow control valve 51' arranged in an oil passage between the right steering assist force generating oil chamber 21 of the hydraulic cylinder 18 and the rotary hydraulic control valve 23. , A second flow rate control valve 52 'arranged in an oil passage between the left steering assist force generating oil chamber 22 and the rotary hydraulic control valve 23. Each flow control valve 51 ', 52' is
As shown in (1) and (2) of FIG.
3'and a valve chamber 54 'formed in the housing 53'
A valve member 55 'contained in the valve chamber 54', a spring 58 'for applying an elastic force to the valve member 55', a spool 63 'contained in the housing 53', and a spool 63 '. It has a spring 64 'for exerting elasticity and a solenoid 65'. Each solenoid 65 'is connected to the control device 71 similar to that of the first embodiment. Each valve member 5
5'has a bypass oil passage 67 '. As shown in FIG. 8 (2), each spool 63 'is displaced downward in the figure against the elastic force of the spring 64' due to the excitation of the solenoid 65 '.
When the spool 63 'is displaced downward in the figure by the excitation of the solenoid 65', each valve member 55 'is displaced downward in the figure by the elasticity of the spring 58'. Obstacle detection sensors 73, 7
When the above signals of 4, 75, and 76 are not transmitted, the valve chamber 54 'of the first flow control valve 51' is connected to the oil chamber 21 for generating the right steering assist force of the hydraulic cylinder 18 via the oil passage and the rotary hydraulic pressure. The valve chamber 54 'of the second flow rate control valve 52' is connected to the right steering recess 27 of the control valve 23, and the left steering assist force generating oil chamber 22 of the hydraulic cylinder 18 and the rotary hydraulic control via the oil passage. It is connected to the left steering recess 28 of the valve 23. The flow rate control valves 51 'and 52' are throttle portions that reduce the opening degree of the oil passage between the rotary hydraulic control valve 23 and the hydraulic cylinder 18 according to the downward movement of the valve member 55 'in the figure. 5
9 '.

As shown in FIG. 8 (1), the solenoid 6
In the state where 5'is not excited and the valve member 55 'is located at the upper side in the figure, the throttle portion 59' is fully opened. As shown in FIG. 8B, when the solenoid 65 'is excited and the valve member 55' is displaced downward in the figure, the throttle portion 59 'is fully closed. Further, as shown in (2) of FIG. 8, when the throttle portion 59 'is fully closed, the valve chamber 54' is closed.
Is connected to the low-pressure side tank 41 via a bypass oil passage 67 ', and in other states, the outlet of the bypass oil passage 67' is closed as shown in (1) of FIG. Other configurations are similar to those of the first embodiment.

According to the fourth 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 causes the right steering suppression signal. The solenoid 65 'of the first flow control valve 51'
To energize the solenoid 65 '. By the excitation, as shown in (2) of FIG.
The spool 63 'of 1'moves downward in the figure, the valve member 55' also moves downward in the figure with the movement of the spool 63 ', and the throttle portion 59' is fully closed. This first flow control valve 5
By driving 1 ', the flow rate of pressure oil for generating the right steering assist force between the oil chamber 21 of the hydraulic cylinder 18 and the rotary hydraulic control valve 23 decreases to zero, and the movement of the hydraulic cylinder 18 is locked. The right steering force is suppressed. When the right steering restraint signal is released, the spool 63 'of the first flow control valve 51' is spring 64 'as shown in (1) of FIG.
Is moved upward in the figure by the elasticity of the valve 63, and the valve member 55 'is also moved upward in the figure with the movement of the spool 63'.
Since 9'is fully opened, the restraint force for right steering is not generated.

When the left obstacle detection sensors 75 and 76 detect an obstacle, the control device 71 sends a left steering suppression signal to the solenoid 65 'of the second flow control valve 52' to excite the solenoid 65 '. . Due to the excitation, the oil chamber 2 of the hydraulic cylinder 18 is processed in the same manner as when the right steering suppression signal is generated.
2 and the rotary hydraulic control valve 23 so that the pressure oil flow rate for generating the left steering assist force decreases and becomes zero.
The flow control valve 52 'is driven. As a result, the movement of the hydraulic cylinder 18 is locked and a left steering restraining force is generated. When the left steering restraint signal is released, the spool 63 ′ of the second flow control valve 52 ′ moves upward in the figure by the elasticity of the spring 64 ′, and the throttle is stopped in the same manner as when the right steering restraint signal is released. Since the portion 59 'is fully opened, the restraint force for left steering is not generated.

When the vehicle is steered to the left while the right steering suppression signal is being generated, the rotary hydraulic control valve 23 causes the right steering assist force generating oil chamber 21 to move to the first flow rate control valve 51. The low pressure oil is stored in the tank 41 through the'valve chamber 54 '.
To the first flow control valve 5 due to the low-pressure oil flow.
The 1'valve member 55 'is moved in a direction to increase the opening degree of the throttle portion 59' against the elastic force of the spring 58 '. That is, since the first flow rate control valve 51 'does not reduce the pressure oil flow rate for generating the left steering assist force between the oil chamber 21 of the hydraulic cylinder 18 and the rotary hydraulic control valve 23, the left steering wheel is operated. The suppression power of does not occur. Further, when the steering to the right is performed while the left steering suppression signal is being generated, as in the case where the steering to the left is performed when the right steering suppression signal is generated, The two-flow-rate control valve 52 'does not reduce the pressure oil flow rate for generating the right steering assist force between the oil chamber 22 of the hydraulic cylinder 18 and the rotary hydraulic control valve 23, so that the right steering control force is suppressed. Will never occur.

In the state where the right steering restraining force is generated, the valve chamber 54 'of the first flow control valve 51' is connected to the tank 41 via the bypass oil passage 67 '.
The high pressure oil guided to the flow control valve 51 'can be returned to the low pressure side. Further, in a state where the left steering suppression force is generated, the valve chamber 54 'of the second flow rate control valve 52' is connected to the tank 41 via the bypass oil passage 67 ', so that the second flow rate control valve The high pressure oil introduced to 52 'can be returned to the low pressure side. As a result, when the driver applies a steering force regardless of the steering suppression, it is possible to prevent a problem from occurring due to the hydraulic pressure exceeding the relief pressure of the pump 37 acting. Since the movement of the hydraulic cylinder 18 is locked during steering suppression, the magnitude of the steering suppression force is constant regardless of the steering force applied by the driver. Other actions and effects are similar to those of the first embodiment.

FIG. 9 shows a fifth embodiment of the present invention. The difference from the fourth embodiment is that each flow control valve 51 ', 5'
2'is not provided with a structure for connecting the valve chamber 54 'to the tank 41 at the time of driving, and when the driver increases the steering force from the state in which the steering suppression force is generated, the relief of the pump 37 is provided. This is at the point where the valve 83 is opened to recirculate the high pressure oil to the tank 41. Others are the same as those in the fourth embodiment, and the same portions are denoted by the same reference numerals.

A sixth embodiment of the present invention will be described with reference to FIGS.

The rack and pinion type hydraulic power steering apparatus 101 shown in FIG. 10 has an input shaft 2 connected to the steering wheel H and a torsion bar (not shown) on the input shaft 2 as in the first embodiment. An output shaft 4 to be connected, and a pinion 7 formed on the output shaft 4,
A cylinder tube provided with a rack 8 that meshes with the pinion 7, and a rack housing 10b;
A steering assist force is generated by a hydraulic cylinder 18 having a piston 20 integrated with the rack 8.

The right steering assisting force generating oil chamber 21 and the left steering assisting force generating oil chamber 22 of the hydraulic cylinder 18 are rotary hydraulics similar to those of the first embodiment via a steering restraining mechanism 150 described later. When the steering valve is connected to the control valve 23 and steering is not suppressed, when the steering wheel is steered from the midpoint of the steering angle to the right, high pressure oil having a pressure corresponding to the steering force is supplied from the pump 37 to one oil chamber 21 of the hydraulic cylinder 18. Supplied and hydraulic cylinder 18
Low-pressure oil is returned from the other oil chamber 22 to the tank 41,
When the steering wheel is steered to the left from the midpoint of the steering angle, high-pressure oil having a pressure corresponding to the steering force is supplied from the pump 37 to the other oil chamber 22 of the hydraulic cylinder 18, and from one oil chamber 21 of the hydraulic cylinder 18 to the tank 41. The low pressure oil is refluxed.

The steering restraint mechanism 150 is a first restraint mechanism 151 for restraining the right steering, which is arranged in an oil passage between the oil chamber 21 for generating the right steering assist force of the hydraulic cylinder 18 and the rotary hydraulic control valve 23. And a second suppressing mechanism 152 for suppressing left steering, which is arranged in an oil passage between the left steering assist force generating oil chamber 22 and the rotary hydraulic control valve 23.

As shown in FIG. 11, each of the suppressing mechanisms 151 and 152 includes a main body 153, a first port 155 connected to the control valve 23 through a pipe connection connector 154, and a hydraulic cylinder 18 for pipe connection. The second port 157 connected via the connector 156, the check valve 159 located in the main oil passage 158 connecting the first port 155 and the second port 157, and the first port 155 and the second port 1
57 and a spool 161 that opens and closes a bypass oil passage 160.

The check valve 159 blocks the flow of high-pressure oil from the control valve 23 to the hydraulic cylinder 18 in the main oil passage 158 by the elasticity of the spring 162, and the oil flow from the hydraulic cylinder 18 to the control valve 23 is prevented. Tolerate. That spool 16
Reference numeral 1 has a circumferential groove 161a, which is urged by a spring force of the spring 163 in a direction (leftward in the figure) in which the bypass oil passage 160 is opened via the circumferential groove 161a. The spool 161 is connected to a solenoid 165, and the solenoid 165 is connected to a drive circuit 170 described later. The spool 161 closes the bypass oil passage 160 by the outer peripheral surface due to the displacement to the right in the figure due to the excitation of the solenoid 165.

As shown in FIG. 10, each suppressing mechanism 151,
The solenoid 165 of 152 is connected to the output terminal of the drive circuit 170. At the input terminal of the drive circuit 170,
Steering suppression cause detection device 171 and vehicle speed detection sensor 172
And the deceleration operation detection sensor 173 are connected.

As shown in FIG. 12, the steering restraint cause detecting device 171 detects a right steering restraint cause detecting signal 1 based on signals from a plurality of obstacle detecting sensors mounted on the vehicle.
75 and the left steering suppression cause detection signal 176 are transmitted to the drive circuit 1
It is configured by what is output to 70. The vehicle speed detection sensor 172 is configured by a device that outputs a pulse signal having a frequency corresponding to the vehicle speed. The deceleration operation detection sensor 173 is closed by the operation of the brake and opened by releasing the operation of the brake operation detection switch 177.
And an accelerator operation detection switch 178 which is closed by the operation of the accelerator and opened by releasing the operation.

In the drive circuit 170, the right steering suppression cause detection signal 175 is input to the first AND circuit 180 as an H signal, and the left steering suppression cause detection signal 176 is input.
Is input as an H signal to the second AND circuit 181. The vehicle speed detection sensor 172 includes a frequency-voltage conversion circuit 19
It is connected to the comparison circuit 182 via 0. The comparison circuit 182 outputs a set vehicle speed detection signal when the vehicle speed detected by the vehicle speed detection sensor 172 exceeds a set value, and the set vehicle speed detection signal is input to the third AND circuit 183 as an H signal. The brake operation detection switch 177
Is connected to the inverter 185 via the grounded resistor 184, is connected to the input terminal of the third AND circuit 183 via the inverter 185, and the third AND circuit 1
When the brake operation detection switch 177 is opened at 83, the H signal is input. The accelerator operation detection switch 1
78 is connected to the input terminal of the third AND circuit 183 via the grounded resistor 186.
3 when the accelerator operation detection switch 178 is closed
A signal is input. The output terminal of the third AND circuit 183 is connected to the input terminal of the first AND circuit 180 and the input terminal of the second AND circuit 181. The output terminal of the first AND circuit 180 is connected to the base of the first transistor 187, and the collector of the first transistor 187 is connected to the solenoid 165 of the first suppressing mechanism 151. The output terminal of the second AND circuit 181 is connected to the base of the second transistor 188, and the collector of the second transistor 188 is connected to the solenoid 165 of the second suppression mechanism 152. Power source 1 for each solenoid 165
89, the emitters of the transistors 187 and 188 and the power supply 189 are grounded.

According to the configuration of the sixth embodiment described above, the steering can be switched between the state in which the steering restraining force can be applied and the state in which the steering restraining force can be released regardless of the presence or absence of steering, and steering toward the detected steering restraining cause. It is possible to switch to a state in which the steering suppression force can be applied only to.

That is, the brake operation detection switch 17
7 is opened, the accelerator operation detection switch 178 is closed, the vehicle speed exceeds the set speed, and the steering suppression cause detection device 171 detects the right steering suppression cause, the third AND circuit 183 outputs the H signal to the first logic. It outputs to the product circuit 180 and the second AND circuit 181 and the first AND circuit 180 outputs the H signal to the base of the first transistor 187. As a result, the first transistor 187 is turned on and the solenoid 165 of the first suppression mechanism 151 is excited. Due to the excitation of the solenoid 165, the spool 161 moves to the bypass oil passage 1
By closing 60, the steering control force can be applied to the right steering. When the right steering is performed in this state, the main oil passage 1 of the first suppressing mechanism 151 is removed from the control valve 23.
The check valve 159 prevents the high-pressure oil that has flowed into 58 from reaching the oil chamber 21 for generating the right steering assisting force of the hydraulic cylinder 18, whereby the steering assisting force is not generated,
Steering suppression force for right steering is applied. Further, when the left steering is performed in this state, the return oil flowing from the right steering assist force generating oil chamber 21 of the hydraulic cylinder 18 into the bypass oil passage 160 opens the check valve 159 and thus passes through the control valve 23. Therefore, the steering control force for the left steering is not applied when the cause of the left steering suppression is not detected.

Similarly, a brake operation detection switch 177 is provided.
Is opened, the accelerator operation detection switch 178 is closed, the vehicle speed exceeds the set speed, and the left steering suppression cause is detected by the steering suppression cause detection device 171, the third AND circuit 183 outputs the H signal to the first AND. The signal is output to the circuit 180 and the second AND circuit 181, and the second AND circuit 181 outputs the H signal to the base of the second transistor 188. As a result, the second transistor 188 is turned on and the solenoid 165 of the second suppressing mechanism 152 is excited. By exciting the solenoid 165, the steering control force can be applied to the left steering as in the case where the right steering control cause is detected.

When the cause of the steering restraint is not detected, the solenoids 165 of the restraint mechanisms 151 and 152 are demagnetized, so that the steering restraining force can be released.

When the vehicle speed is equal to or lower than the set speed, the third AND circuit 183 outputs the L signal to the first AND circuit 180 and the second signal.
And the first AND circuit 18
0 and the second AND circuit 181 outputs the L signal to each transistor 1
87, 188 to output the respective transistors 187, 188
Is turned off, the solenoid 165 of each suppressing mechanism 151, 152 is demagnetized. As a result, the spool 161
Opens the bypass oil passage 160, and the high-pressure oil from the control valve 23 reaches the hydraulic cylinder 18 via the bypass oil passage 160, so that the steering restraining force can be released. Further, when the brake operation detection switch 177 is closed by the brake operation, or when the accelerator operation detection switch 178 is opened by the release of the accelerator operation, the respective restraining mechanisms 151, 152 are similar to the case where the vehicle speed is equal to or lower than the set speed. The solenoid 165 is demagnetized and is switched to a state where the application of the steering restraining force can be released. This prevents the vehicle from passing through a curved road with a narrow vehicle width and avoiding obstacles in front of the vehicle. It is possible to prevent the vehicle from deviating from the vehicle and colliding with a front obstacle.

The speed at which the application of the steering restraining force is released is delayed according to the steering force. That is, the spool 161 is shown in FIG.
The solenoid 16 is moved to the right in FIG.
5 is demagnetized, the spring 163 is
An elastic force is applied to move the spool 161 to the left so that 0 opens. At this time, when the steering force acts, the pressure of the high-pressure oil flowing from the control valve 23 into the main oil passage 158 acts as a movement blocking force of the spool 161. The movement preventing force of the spool 161 depends on the steering force because the pressure of the high-pressure oil flowing from the control valve 23 into the main oil passage 158 depends on the steering force as described above. Therefore, the larger the steering force is, the larger the movement inhibiting force of the spool 161 is, and the slower the release of the steering restraining force is.
It is possible to prevent sudden turning due to sudden release of the steering restraining force.

Incidentally, the respective suppression mechanisms 151, 1 shown in FIG.
At 52, the first port 155 is connected to the hydraulic cylinder 18, the second port 157 is connected to the control valve 23, the solenoid 165 of the second suppression mechanism 152 is excited when the right steering is suppressed, and the first suppression is performed when the left steering is suppressed. The solenoid 165 of the mechanism 151 may be excited.

The seventh embodiment of the present invention will be described with reference to FIG.

A rack and pinion type hydraulic power steering device 201 shown in FIG. 13 is connected to an input shaft connected to a steering wheel and a torsion bar (not shown) to this input shaft, as in the first embodiment. The output shaft 4, a pinion 7 formed on the output shaft 4, and a rack 8 that meshes with the pinion 7, and a cylinder tube configured by a rack housing 10b, and a piston 20 integrated with the rack 8 are provided. The hydraulic cylinder 18 has a steering assist force.

The right steering assisting force generating oil chamber 21 and the left steering assisting force generating oil chamber 22 of the hydraulic cylinder 18 are rotary hydraulics similar to those of the first embodiment via a steering restraining mechanism 250 described later. It is connected to the control valve 23.

The steering restraint mechanism 250 includes an electromagnetic first switching valve 251 for restraining the right steering, which is arranged in an oil passage between the oil chamber 21 for generating the right steering assist force of the hydraulic cylinder 18 and the control valve 23. It has an electromagnetic second switching valve 252 for suppressing left steering arranged in an oil passage between the left steering assist force generating oil chamber 22 and the control valve 23, and a suppression force applying actuator 253.

Each of the switching valves 251 and 252 is of a two-position switching type, and has a connection port a with the control valve 23, a connection port b with the hydraulic cylinder 18, a connection port c with the tank 41, and a restraining force imparting actuator. It has a connection port d for connecting to 253, a port switching spool g, a spool operating solenoid e, and a spool return spring f. Each solenoid e has a drive circuit 170 similar to that of the sixth embodiment.
Of the steering suppression cause detecting device 171 similar to that of the sixth embodiment.
And vehicle speed detection sensor 172 and deceleration operation detection sensor 17
3 and 3 are connected.

The suppressing force applying actuator 253 is
An oil chamber 253a provided in a rack housing (not shown) that supports the output shaft 4 and the output shaft 4 in the oil chamber 253a.
The plunger 25 inserted so as to be movable along the radial direction of the
3b, and the tip of each plunger 253b has an output shaft 4
The oil chamber 253a is connected to the switching valves 251 and 252.

According to the configuration of the seventh embodiment described above, the steering restraining force can be switched to the state in which the steering restraining force can be applied and the state in which the steering restraining force can be released regardless of the presence or absence of steering, and the steering restraining force depends on the steering force. The steering control force is switched to the state in which the steering control force can be applied only to the steering directed to the detected steering control cause.

That is, each switching valve 2 in FIG.
Nos. 51 and 252 are in a state where steering is not suppressed, and when steering from the midpoint of the steering angle to the right, the control valve 23 and the first switching from the pump 37 to the oil chamber 21 for generating the right steering assist force of the hydraulic cylinder 18. High-pressure oil having a pressure corresponding to the steering force is supplied via the valve 251 to the second switching valve 2 from the left steering assist force generating oil chamber 22 of the hydraulic cylinder 18 to the tank 41.
The low-pressure oil is recirculated through the control valve 52 and the control valve 23, and a right steering assist force is generated. Further, when the steering wheel is steered to the left from the midpoint of the steering angle, high pressure oil having a pressure corresponding to the steering force is supplied from the pump 37 to the left steering assist force generating oil chamber 22 via the control valve 23 and the second switching valve 252. The oil chamber 2 for generating the right steering assist force
1 to tank 41 First switching valve 251 and control valve 23
The low-pressure oil is recirculated via and to generate a left steering assist force.

The brake operation detection switch 177 opens,
When the accelerator operation detection switch 178 is closed, the vehicle speed exceeds the set speed, and the steering suppression cause detection device 171 detects the right steering suppression cause, the steering suppression cause detection device 1
From 71, a right steering suppression cause detection signal 175 is output to the solenoid e of the first switching valve 251. As a result, the first switching valve 251 is switched, the connection port a with the control valve 23 is connected with the connection port d with the suppression force imparting actuator 253, and the connection port b with the hydraulic cylinder 18 is the connection port with the tank 41. It is in a state of being connected to c. When the right steering is performed in this state, the hydraulic cylinder 1
No high pressure oil is supplied to the right steering assist force generating oil chamber 21 of FIG. 8, and high pressure oil corresponding to the steering force is supplied from the control valve 23 to the suppression force applying actuator 253. The force is applied according to the steering force. Further, when the left steering is performed in this state, the high pressure oil having a pressure corresponding to the steering force is supplied from the pump 37 to the left steering assist force generating oil chamber 22 via the control valve 23 and the second switching valve 252. The low-pressure oil is circulated from the right steering assist force generating oil chamber 21 to the tank 41 via the first switching valve 251 to generate the left steering assist force.

Similarly, a brake operation detection switch 177 is provided.
Is opened, the accelerator operation detection switch 178 is closed, the vehicle speed exceeds the set speed, and the steering suppression cause detection device 171 detects the left steering suppression cause, the steering suppression cause detection device 171 outputs the left steering suppression cause detection signal 176. Is the second
It is output to the solenoid e of the switching valve 252. As a result, the second switching valve 252 is switched, and the control valve 2
The connection port a with 3 is a restraining force applying actuator 253.
And the connection port b with the hydraulic cylinder 18 is connected with the connection port c with the tank 41. When the left steering is performed in this state, the high pressure oil is not supplied to the left steering assist force generating oil chamber 22 of the hydraulic cylinder 18, and the control valve 23 applies the high pressure oil corresponding to the steering force to the suppression force applying actuator 253. Since the oil is supplied, the steering restraining force for the left steering is applied according to the steering force. Further, when the right steering is performed in this state, the high pressure oil having a pressure corresponding to the steering force is supplied from the pump 37 to the right steering assist force generating oil chamber 21 via the control valve 23 and the first switching valve 251. The low-pressure oil is circulated from the left steering assist force generating oil chamber 22 to the tank 41 via the second switching valve 252, and the right steering assist force is generated.

The pump 37 and the control valve 23 are connected to the tank 41 via a fixed throttle 260 so that an excessive steering restraining force does not act.

Further, when the cause of steering suppression is not detected, when the vehicle speed is below the set speed, when the brake operation detection switch 177 is closed by the brake operation, or when the accelerator operation is released, the accelerator operation detection switch 178 is opened. In this case, the solenoid e of each of the switching valves 251 and 252 is demagnetized, so that the steering restraining force can be released.

The eighth embodiment of the present invention will be described with reference to FIGS.

The rack and pinion type electric power steering device 301 shown in FIG. 14 includes an input shaft 302 connected to a steering wheel H of a vehicle 310 and the input shaft 3.
Output shaft 3 connected to the No. 02 via a torque sensor 303
04 and. The output shaft 304 is connected to the pinion 306 via a universal joint 305,
A steering wheel 308 is connected to a rack 307 that meshes with the pinion 306. As a result, the steering torque is changed to the steering wheel H, the input shaft 302, and the torque sensor 30.
3 is transmitted to the rack 307 via the output shaft 304 and the pinion 306, and the vehicle 310 is steered by the movement of the rack 307.

A worm wheel 312 is fitted around the outer circumference of the output shaft 304, and a worm gear 315 meshing with the worm wheel 312 is connected to a steering assist force generating motor 313. The torque sensor 303 detects the steering torque transmitted from the input shaft 302 to the output shaft 304.

The torque sensor 303 is connected to a characteristic conversion unit 320, which will be described later, and the characteristic conversion unit 320 is connected to the steering suppression cause detection device 321. The steering suppression cause detecting device 321 is similar to the sixth embodiment in that the vehicle 31
A plurality of obstacle detection sensors 323, 3 attached to 0
Based on the signals from 24, 325, and 326, the right steering suppression cause detection signal 331 and the left steering suppression cause detection signal 332 are output to the characteristic conversion unit 320.
The characteristic conversion section 320 and the steering suppression cause detection device 321 constitute a safety control unit 390. The characteristic conversion unit 320 is connected to the motor 313 via the steering control unit 391.

As shown in FIG. 15, the characteristic converting section 320 includes a steering suppression cause determining section 333 and a switching section 334.
A current-voltage converter 335 and a left-right characteristic converter 336.
And a right characteristic conversion unit 337 and a left characteristic conversion unit 338.

The steering restraint cause determining section 333 has the first to third
It is composed of the fourth AND circuits 341 to 344. The input terminal R of the right steering suppression cause detection signal 331 is connected to the input sides of the first AND circuit 341 and the fourth AND circuit 344 via the inverter 339, and the second AND circuit 342 and the third AND circuit 342 are connected. It is directly connected to the input side of the AND circuit 343. The input terminal L of the left steering suppression cause detection signal 332.
Of the first AND circuit 341 and the third AND circuit 343.
Of the second AND circuit 342 and the fourth AND circuit 344 are directly connected to the input side of the second AND circuit 342 via the inverter 340. As a result, when neither the right steering suppression cause detection signal 331 nor the left steering suppression cause detection signal 332 is output, the first AND circuit 341 outputs the H signal and the other AND circuits output the L signal. When both of the steering suppression cause detection signals 331 and 332 are output,
The second AND circuit 342 outputs the H signal, the other AND circuits output the L signal, and when only the right steering suppression cause detection signal 331 is output, the third AND circuit 343 outputs the H signal. When the other AND circuit outputs the L signal and only the left steering suppression cause detection signal 332 is output, the fourth AND circuit 344 outputs the H signal and the other AND circuit outputs the L signal.
Output a signal.

The switching unit 334 is composed of first to fourth opening / closing switches 351 to 354. The first opening / closing switch 351 opens / closes between the current / voltage conversion unit 335 and the output terminal M to the steering control unit 391, and is closed by the H signal from the first AND circuit 341 and opened by the L signal. Be done. The second open / close switch 35
Reference numeral 2 is for opening / closing between the left / right characteristic conversion unit 336 and the output terminal M, which is closed by the H signal from the second AND circuit 342 and opened by the L signal. The third open / close switch 353 opens / closes between the right characteristic conversion unit 337 and the output terminal M, and is closed by the H signal from the third AND circuit 343 and opened by the L signal. The fourth open / close switch 354 opens / closes between the left characteristic conversion unit 338 and the output terminal M, and is closed by the H signal from the fourth AND circuit 344 and opened by the L signal.

The current-voltage converter 335 converts a current signal corresponding to the steering torque detected by the torque sensor 303 into a voltage signal, and is composed of a resistor 361 and a differential amplifier 362. That is, the input terminal T of the torque sensor 303 is grounded through the resistor 361, and the voltage across the resistor 361 is the differential amplifier 362.
Is input to the non-inverting input terminal of the differential amplifier 362, and negative feedback is applied to the differential amplifier 362. (1) of FIG. 16 shows the relationship between the steering torque and the output of the current / voltage conversion unit 335. That is, the output increases in accordance with the steering torque, reaches the power supply voltage, and is saturated.

The left-right characteristic conversion unit 336 converts the output of the current-voltage conversion unit 335 during both right steering and left steering. The resistors 363 and 364, the differential amplifier 365, and the sample hold circuit 366 convert the output. It is configured. That is, the output of the current-voltage conversion unit 335 is input to the inverting input terminal of the differential amplifier 365 via the resistor 363, and the sample hold circuit 366 is also provided.
Is input to the non-inverting input terminal of the differential amplifier 365 via. A resistor 364 is arranged in the negative feedback circuit of the differential amplifier 365. The H signal of the second AND circuit 342 serves as a sampling trigger signal for the sample hold circuit 366. 16 (2), the relationship between the steering torque and the output of the left / right characteristic conversion unit 336 is shown by a solid line, and the relationship between the steering torque and the current / voltage conversion unit 335 is shown by a broken line. That is, the left / right characteristic conversion unit 336
Inverts the output of the current-voltage converter 335 with reference to the output S at the time of sampling by the sample hold circuit 366. The rate of change of the inverted output with respect to the steering torque can be set according to the value of the resistor 364.

The right characteristic conversion unit 337 converts the output of the current-voltage conversion unit 335 only during right steering, and includes resistors 367 to 375, differential amplifiers 376 to 379, and
It is composed of diodes 381 and 382 and a sample hold circuit 380. That is, the output of the current-voltage converter 335 is input to the inverting input terminal of the differential amplifier 376 via the resistor 367, and is also input to the non-inverting input terminal of the differential amplifier 376 via the sample hold circuit 380. It A diode 38 is provided in each of the pair of feedback circuits provided in parallel with the differential amplifier 376.
1, 382 and resistors 368 and 369 are arranged in series, and the forward directions of the pair of diodes 381 and 382 are opposite to each other. Each diode 38 of each feedback circuit
Between the resistor 1, 382 and the resistor 368, 369, the resistor 37
0 and 371 are connected to the sample hold circuit 380 via a differential amplifier 377 that forms a buffer. Also,
One of them is connected to the inverting input terminal of the differential amplifier 378 via a resistor 372, and the other of them is connected to the differential amplifier 3.
Connected to the non-inverting input terminal of 78 through a resistor 373,
A resistor 374 is arranged in the negative feedback circuit of the differential amplifier 378. Further, the H signal of the third AND circuit 343 becomes a trigger signal for sampling by the sample hold circuit 380. Accordingly, when the output of the current-voltage conversion unit 335 exceeds the output of the sample hold circuit 380 at the time of sampling, that is, when the absolute value of the right steering torque becomes larger than that at the time of sampling, one diode 381 is turned on. Since the other diode 382 is turned off, the current-voltage converter 33
The value corresponding to the output of 5 is input to the non-inverting input terminal of the differential amplifier 378. Further, when the output of the current-voltage converter 335 is less than the output of the sample hold circuit 380 at the time of sampling, that is, when the absolute value of the right steering torque becomes smaller than that at the time of sampling, one diode 381 is turned off and the other diode 381 is turned off. Since the diode 382 is turned on, the output of the current-voltage converter 335, that is, the value corresponding to the output of the torque sensor is the differential amplifier 378.
It is input to the inverting input terminal of. The non-inverting input terminal of the differential amplifier 378 is connected to the sample hold circuit 380 via the resistor 375 and the differential amplifier 379 which forms a buffer. 16 (3), the relationship between the steering torque and the output of the right characteristic conversion unit 337 is shown by a solid line, and the relationship between the steering torque and the output of the current / voltage conversion unit 335 is shown by a broken line. That is, the right characteristic conversion unit 337 outputs the output of the current-voltage conversion unit 335 to the sample hold circuit 380.
With reference to the output S at the time of sampling by, the reversal is performed only when the right steering is performed from the time of sampling. The rate of change of the inverted output with respect to the steering torque is determined by the resistance 368.
Can be set according to the value of.

The left characteristic conversion unit 338 converts the output of the current / voltage conversion unit 335 only during left steering, and includes resistors 367 'to 375' and differential amplifiers 376 'to 3'.
79 ', diodes 381' and 382 ', and a sample hold circuit 380'. The H signal of the fourth AND circuit 344 is the sample hold circuit 38.
Except that it becomes a sampling signal by 0 ',
It is connected similarly to the right characteristic conversion unit 337. As a result, when the output of the current-voltage converter 335 exceeds the output at the time of sampling by the sample hold circuit 380 ',
That is, when the absolute value of the left steering torque becomes larger than that at the time of sampling, one diode 381 ′ is turned on and the other diode 382 ′ is turned off, so that a value corresponding to the output of the current-voltage conversion unit 335. Is input to the non-inverting input terminal of the differential amplifier 378 '. When the output of the current-voltage conversion unit 335 is less than the output of the sample hold circuit 380 'at the time of sampling, that is, when the absolute value of the left steering torque becomes smaller than that at the time of sampling, one diode 381' is turned off. Since the other diode 382 'is turned on,
The output of the current-voltage converter 335, that is, the value corresponding to the output of the torque sensor is input to the inverting input terminal of the differential amplifier 378 '. 16 (4), the relationship between the steering torque and the output of the left characteristic conversion unit 338 is shown by a solid line, and the relationship between the steering torque and the output of the current / voltage conversion unit 335 is shown by a broken line. That is, the left characteristic conversion unit 338 outputs the output of the current-voltage conversion unit 335 to the sample hold circuit 38.
The output S at the time of sampling by 0'is used as a reference, and is inverted only when left steering is performed from the time of sampling.
The rate of change of the inverted output with respect to the steering torque is the resistance 3
It may be according to the value of 68 '.

According to the structure of the eighth embodiment, the steering restraining force can be switched to the state in which the steering restraining force can be applied and the state in which the steering restraining force can be released regardless of the presence or absence of steering, and the steering restraining force depends on the steering force. The steering control force is switched to the state in which the steering control force can be applied only to the steering directed to the detected steering control cause.

That is, the left / right steering suppression cause detection signal 33
When both 1 and 332 are not output, the first opening / closing switch 351 is closed and the second to fourth opening / closing switches 352 are closed.
To 354 are opened, only the output of the current-voltage converter 335 can be output to the steering control unit 391, and the output of each characteristic converter 336, 337, 338 is not output to the steering control unit 391. That is, the steering is not suppressed. When steering is performed from the midpoint of the steering angle in this state, the steering control unit 391 applies an output according to the steering torque to the motor 313, and applies a steering assist force according to the steering torque.

Left and right steering suppression cause detection signals 331, 332
Is output, the first opening / closing switch 351 is opened and the second to fourth opening / closing switches 352 to 352 are opened.
Since any of 354 is closed, the output of the current-voltage converter 335 is not directly output to the steering control unit 391, and the output of any one of the characteristic converters 336, 337, 338 is not output to the steering control unit 391. Can be output to, ie, a state in which the steering restraining force can be applied only to the steering directed to the detected steering restraining cause. The steering restraining force increases as the steering torque corresponding to the steering force increases, as shown in (2) to (4) of FIG.

In the eighth embodiment, the sixth,
Similar to the seventh embodiment, it may be possible to switch to a state in which the application of the steering suppression force can be released when the vehicle speed is equal to or lower than a preset value or when the deceleration operation is performed.

The ninth embodiment of the present invention will be described in detail with reference to FIG. FIG. 17 is a schematic diagram showing the overall configuration of an electric power steering device according to the ninth embodiment of the present invention. The overall configuration and operation of the electric power steering apparatus according to this embodiment will be described with reference to FIG.

The steering mechanism includes a steering wheel 401, an input shaft 402 connected to the steering wheel 401, and an output shaft 4 connected to the input shaft 402.
03 and are included. The input shaft 402 and the output shaft 403 are connected via a torsion bar 404. A pinion gear 405 is connected to the end of the output shaft 403, and the pinion gear 405 is used for the rack shaft 4 extending in the vehicle width direction.
It meshes with 06. Tie rod 4 on the rack shaft 406
A tire 408 is attached via 07.

An electric power steering apparatus according to an embodiment of the present invention is incorporated in the steering mechanism as a steering assist system. In the electric power steering device, a torque sensor 410 provided in association with the torsion bar 404, a speed reducer 411 engaged with the output shaft 403, and a clutch 412 on the speed reducer 411.
And a steering control unit 414 for controlling the switching of the clutch 412 as well as controlling the motor 413 for giving a driving force via
And a safety control unit 416 for providing a steering control input signal to the steering control unit 414.

The safety control unit 416 is supplied with the torque voltage T _V from the torque sensor 410 and a vehicle speed signal from a vehicle speed sensor (not shown). These torque voltages T
_{The V} and vehicle speed signals are used as the running state signals that represent the running state of the vehicle. Furthermore, the safety control unit 41
6, the signals from the obstacle sensors 415a, 415b, 415c and 415d are given. Obstacle sensor 4
15a to 415d include, for example, four sensors provided on the side portion and the rear left and right corner portions of the vehicle. These 4
One sensor is for outputting a signal when an obstacle such as another vehicle is approaching from the side or obliquely rear of the vehicle. As the obstacle sensors 415a to 415d, for example, sensors such as ultrasonic sensors and infrared sensors that emit signals such as ultrasonic waves and infrared rays and detect reflected waves thereof can be used. Alternatively, the image reading device such as a CCD and the image processing unit may be combined together. As the obstacle sensor itself, a publicly known one or a commercially available one may be used, and therefore the description of its configuration will be omitted in the present specification.

The safety control unit 416 is switched to a state where no signal is given from any of the obstacle sensors 415a to 415d, that is, when the vehicle is not in a dangerous state, the steering restraining force can be released. In this state, the torque sensor 4 is used for normal assist control.
The torque voltage T _V and the vehicle speed signal from 10 are directly applied to the steering control unit 414. Steering control unit 41
4, the applied torque voltage T _V and the vehicle speed signal are applied to a preset table, the target control value is read from the table, and the control current of the read target control value is supplied to the motor 413. 413 is controlled.

On the other hand, at the time of danger prediction in which a signal is given from any of the obstacle sensors 415a to 415d, the safety control unit 416 is switched to a state where steering restraining force can be applied. In this state, the applied torque voltage T _V is changed to a predetermined voltage value based on the signals from the obstacle sensors 415a to 415d and the vehicle speed signal, and the changed voltage value is used as the torque voltage T _V ′ in the steering control unit 414. Give to. In the steering control unit 414, based on the changed torque voltage T _V ′ and the vehicle speed signal provided from the safety control unit 416, the motor 41
3 determines the target control current value to be given to
To control.

Table 1 shows an outline of a method of changing the torque voltage T _V as the running state signal performed in the safety control unit 416 according to the presence or absence of the signals of the obstacle sensors 415a to 415d as the danger prediction signal. Is represented. In this table, the influence of the vehicle speed signal is omitted for simplicity.

[0112]

[Table 1]

In Table 1, reference numerals "a", "b", "-c"
“-D” indicates a voltage value, respectively, and −d <−c
It is assumed that there is a relationship of <b <a. Further, when the torque voltage T _V is “a” or “b”, it indicates right steering, and “−c” or “−”.
In the case of "d", left steering is shown. Safety control unit 4
The torque voltage T _V given to 16 is “a” or “b”
At this time, if no signal is given from any of the obstacle sensors 415a to 415d, the torque voltage T _V remains unchanged as "a" or "b" and remains in the safety control unit 4
16 to the steering control unit 414. Also,
It remains "a" or "b" even if there is a signal from the obstacle sensor 415a or 415c provided on the left side of the vehicle. This is a case where an obstacle is approaching from the left side or the left rear side of the vehicle when there is a signal from the obstacle sensor 415a or 415c. In such a case, when the vehicle is about to be steered to the right,
There is no danger. Therefore, the torque voltage T _V is output as it is.

However, when the torque voltage T _V is "a" or "b" and there is a signal from the obstacle sensor 415b or 415d provided on the right side of the vehicle, the torque voltage T _V is changed. . This is because the vehicle is about to be steered to the right even though there is an obstacle on the right side or the rear side on the right side of the vehicle. In this case, the torque voltage T _V is “a” so that the steering wheel 1 is in a so-called locked state so that the vehicle is not steered to the right or the motor 13 is forced to steer the steering wheel 1 to the left. In case of "-d",
When it is "b", it is changed to "-c". That is, the steering restraining force corresponds to the steering force.

Similarly, as shown in Table 1, when the vehicle is about to be steered to the left, any obstacle sensor 4
If there is no signal from 15a to 415d or if there is a signal from the obstacle sensor 415b or 415d provided on the right side of the vehicle, the torque voltage T _V remains unchanged, but the obstacle provided on the left side of the vehicle. When there is a signal from the object sensor 15a or 15c, the torque voltage T _V is changed to T _V ′ so that the steering wheel 1 is steered to the right.

The torque voltage T _V ′ thus changed by the safety control unit 416 is directly applied to the steering control unit 414. Therefore, the steering control unit 41
4, a table as shown in Table 2 is searched based on the applied torque voltage T _V ′ and the vehicle speed signal, the corresponding target control current i _k is read, and the current is read by the motor 41.
3 may be supplied. Therefore, the steering control unit 414
The existing steering control unit can be used as it is.

[0117]

[Table 2]

Further, in the ninth embodiment, the steering control unit 414 has a torque voltage T as shown in Table 2, for example.
A table of target control current values that can be searched by _V and the vehicle speed signal is preset, and the applied torque voltage T
_It has been described that the target control current value is read from this table based on _V or T _V ′ and the vehicle speed signal.
However, the existing steering control unit 414 does not have a table in advance, and there is one that calculates the target control current value every time the torque voltage T _{V, the} vehicle speed signal, etc. are given. Even in the unit 414, the present invention can be configured by using an existing unit as it is.

The present invention can be variously modified within the scope of the claims and is not limited to the above embodiments. For example, in the first to fifth embodiments, the flow control valve for suppressing right steering and the flow control valve for suppressing left steering are
It may be integrated as long as it can perform each function. Also, both flow rate control valves are placed in the oil passage between one of the left and right steering assist force generating oil chambers and the rotary hydraulic control valve. The high-pressure oil may be throttled by the throttle portion and the low-pressure oil discharged from the hydraulic actuator may be throttled by the throttle portion when the other steering control is performed. In addition, the present invention other than the rack and pinion type,
For example, it may be applied to a ball screw type power steering device.

[0120]

According to the present invention, it is not necessary to judge the presence or absence of steering and the direction in order to determine whether or not to suppress steering, and the control system can be simplified. By making the steering suppression force according to the steering force, appropriate steering suppression can be performed without complicating the control system. Further, the control system can be simplified by applying the steering suppression force only to steering in the direction in which the steering suppression is required without performing control for switching the acting direction of the steering suppression force according to the steering direction. Further, when the vehicle speed is equal to or lower than a preset value or when the vehicle is switched to a state in which the steering restraining force can be released during the deceleration operation, it is possible to prevent the vehicle from deviating from the traveling path or colliding with a front obstacle. By delaying the speed at which the application of the steering suppression force is released according to the steering force, it is possible to prevent sudden turning due to the sudden release of the steering suppression force. By applying the present invention to a hydraulic power steering device and generating a steering suppression force by high pressure oil having a pressure corresponding to the steering force via a hydraulic control valve, appropriate steering suppression can be performed without complicating the control system, Furthermore, steering can be suppressed only in the steering direction where there is a possibility of collision with an obstacle without using a dedicated actuator, and the structure of the control device for outputting the steering suppression signal can be simplified, resulting in excessive hydraulic pressure. It is possible to prevent a defect due to the action of. In addition, a controller such as a steering control unit in an existing electric power steering apparatus can be used as it is, and a safety control steering function for avoiding danger can be added to the electric power steering apparatus. Since the existing controller such as the steering control unit can be utilized in this manner, the electric power steering apparatus can be constructed at low cost as a whole. Further, it is possible to easily retrofit a safety control function for avoiding a danger to an existing electric power steering device.

[0121]

[Disclosure of Other Techniques] FIG. 19 discloses a technique different from the present invention. 19, the same parts as those in the first embodiment of the present invention are designated by the same reference numerals, and only different points will be described. First, in order to detect the steering direction, the input shaft 2
A torque sensor 81 for detecting the steering torque transmitted from the output shaft 4 to the output shaft 4 is provided, and the torque sensor 81 is connected to the control device 71. When the obstacle detection signal from one of the right obstacle detection sensors 73 and 74 and the torque detection signal corresponding to the right steering from the torque sensor 81 are input, the control device 71 amplifies the input signal. The solenoid drive current is transmitted to the solenoid 65 of the first electromagnetic switching valve 61 as a right steering suppression signal. Further, when the obstacle detection signal from one of the left obstacle detection sensors 75 and 76 and the torque detection signal corresponding to the left steering from the torque sensor 81 are input, the control device 71 outputs the input signal. The amplified solenoid drive current is transmitted to the solenoid 65 of the second electromagnetic switching valve 62 as a left steering suppression signal. That is, the control device 71 outputs the solenoid drive current obtained by amplifying the input signal as a steering suppression signal to the solenoid 65 of the electromagnetic switching valves 61 and 62 corresponding to the steering direction detected by the torque sensor 81. According to the disclosed technique, the right steering suppression signal is transmitted by detecting an obstacle having a possibility of collision in the right steering direction and detection of right steering, and the left steering suppression signal is notified of a possibility of collision in the left steering direction. By transmitting by detection of an obstacle and detection of left steering, the steering suppression signal of each flow control valve is output corresponding to the detection signal of each obstacle and the detection signal of the steering direction. As a result, by only outputting the steering suppression signal in correspondence with the obstacle detection signal and the steering direction detection signal, it is possible to carry out steering suppression only in the steering direction where there is a possibility of collision with the obstacle. The configuration of the control device for outputting the steering suppression signal can be simplified.

[Brief description of drawings]

FIG. 1 is a vertical 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 a first embodiment of the present invention.

FIG. 4 is a flow chart of the flow control valve according to the first embodiment of the present invention in which (1) is an operation explanatory diagram when steering suppression is released, (2) is an operation explanatory diagram when steering suppression is released, and (3) is a maximum steering suppression force. Illustration of action at time

FIG. 5 is a configuration diagram of a hydraulic power steering device according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram of a hydraulic power steering device according to a third embodiment of the present invention.

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

FIG. 8 is a flow chart of the flow control valve according to the fourth embodiment of the present invention, in which (1) is an operation explanatory diagram when steering suppression is released, and (2) is an operation explanatory diagram when steering is suppressed.

FIG. 9 is a configuration diagram of a hydraulic power steering device according to a fifth embodiment of the present invention.

FIG. 10 is a configuration diagram of a hydraulic power steering device according to a sixth embodiment of the present invention.

FIG. 11 is a sectional view of a suppressing mechanism of a hydraulic power steering device according to a sixth embodiment of the present invention.

FIG. 12 is a structural explanatory view of a drive circuit of a hydraulic power steering device according to a sixth embodiment of the present invention.

FIG. 13 is a configuration diagram of a hydraulic power steering device according to a seventh embodiment of the present invention.

FIG. 14 is a configuration diagram of an electric power steering device according to an eighth embodiment of the present invention.

FIG. 15 is a configuration explanatory view of a characteristic conversion unit of an electric power steering system according to an eighth embodiment of the present invention.

FIG. 16 is a steering assist state, (2) left and right steering restrained state, (3) right steering restrained state, and (4) left steering restrained state of the electric power steering system according to the eighth embodiment of the present invention. Showing the relationship between the steering torque and the drive circuit output in the state

FIG. 17 is a schematic diagram showing an overall configuration of an electric power steering device according to a ninth embodiment of the present invention.

FIG. 18 is a schematic diagram of a control circuit configuration in an electric power steering apparatus according to the applicant's prior application.

FIG. 19 is a configuration diagram of a hydraulic power steering device according to another technique.

[Explanation of symbols]

1, 101, 201, 301 Power steering device 18 Hydraulic cylinder 21 Right steering assist force generating oil chamber 22 Left steering assist force generating oil chamber 23 Rotary hydraulic control valve 51, 51 'First flow control valve 52, 52' Second flow rate control valve 55, 55 'Valve member 56 Pressure sensing chamber 61 First electromagnetic switching valve 62 Second electromagnetic switching valve 65, 65' Solenoid 67, 67 'Bypass oil passage 71 Control device 73, 74, 75, 76 Fault Object detection sensor 81 Torque sensor 150, 250 Steering suppression mechanism 170 Drive circuits 171, 321 Steering suppression cause detection device 172 Vehicle speed detection sensor 173 Deceleration operation detection sensor 253 Suppression force imparting actuator 401 Steering wheel 402 Input shaft 403 Output shaft 404 Torsion bar 410 Torque sensor 413 Motor 414 Steering control unit 415a, 415b, 415c, 415d obstacle sensor 416 Safety control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiro Nakano 3-5-8 Minamisenba, Chuo-ku, Osaka-shi, Osaka Within Koyo Seiko Co., Ltd. No. 8 in Koyo Seiko Co., Ltd. (56) Bibliography Sho 63-91976 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 6/00 B62D 5/04

Claims (13)

(57) [Claims] 1. A steering apparatus for a vehicle comprising a means for suppressing steering by the driver is switched on and performed state grant release and allow state grant regardless steering restraining force on the presence or absence of steering, the steering inhibition The force increases as the steering force increases.
A steering device for a vehicle that is said to respond to the steering force . 2. A means for suppressing steering by a driver is provided.
In the steering system of the vehicle, the steering restraint force can be applied regardless of whether steering is performed or not.
Switched grant released and allow state, Bei means for detecting a steering inhibition causes in the right steering direction, and means for detecting a steering inhibition causes in the left steering direction
However, steering is performed only for steering directed to the detected steering suppression cause.
A vehicle steering system that can be switched to a state in which it can apply restraining force . 3. A means for detecting a vehicle speed, wherein a solution for applying a steering restraining force is provided when the vehicle speed is below a preset value.
The steering apparatus for a vehicle according to claim 1 or 2, which is switched to a state in which the steering wheel can be removed . 4. A means for suppressing steering by a driver is provided.
In the steering system of the vehicle, the steering restraint force can be applied regardless of whether steering is performed or not.
Imparting release is switched to and performed state, comprising means for detecting a deceleration operation, vehicles of the steering device that is switched to allow the state to grant release of steering inhibition force when subjected to deceleration. 5. A means for suppressing steering by a driver is provided.
In the steering system of the vehicle, the steering restraint force can be applied regardless of whether steering is performed or not.
It is switched to a state where it can be released, and the speed of releasing the steering restraining force is slower according to the steering force.
The vehicle steering system. 6. A means for suppressing steering by a driver is provided.
In the steering system of the vehicle, the steering restraint force can be applied regardless of whether steering is performed or not.
It is switched to a state where the application can be released, and the oil chamber for generating the right steering assist force and the oil chamber for generating the left steering assist force are separated.
It has a hydraulic actuator and a high pressure from the pump to one oil chamber depending on the steering direction and the steering force.
Guide the pressure oil and the low pressure oil from the other oil chamber to the tank.
A control valve, a means for detecting a steering restraint cause in the right steering direction , a means for detecting a steering restraint cause in the left steering direction, and a right steering operation based on detection of the steering restraint cause in the right steering direction
Sends a suppression signal to indicate the cause of steering suppression in the left steering direction.
The control is performed by means of transmitting a left steering suppression signal based on the detection and at least one of the left and right steering suppression signals.
Steering suppression force is added by high pressure oil according to the steering force through the valve.
A steering device for a vehicle, comprising: 7. A means for suppressing steering by a driver is provided.
In the steering system of the vehicle, the steering restraint force can be applied regardless of whether steering is performed or not.
Switched grant released and allow state, high-pressure oil and the hydraulic actuator, the one oil chamber from the pump according to the steering Direction and a rightward steering assist force generating oil chamber and left steering assist force generating hydraulic chamber Control valve that guides low pressure oil from the other oil chamber to the tank, means for detecting the cause of steering suppression in the right steering direction, means for detecting the cause of steering suppression in the left steering direction, its hydraulic actuator and control valve. Placed in the oil passage between
Is installed in the oil passage between the hydraulic control valve and the flow control valve for suppressing the right steering.
And a means for transmitting a right steering suppression signal based on detection of a steering suppression cause in the right steering direction and a left steering suppression signal based on detection of a steering suppression cause in the left steering direction. , For the right steering assist force generation by the right steering suppression signal
Install a flow control valve for right steering suppression to reduce the pressure oil flow rate.
The means for driving and the left steering suppression signal are used to generate the left steering assist force.
Install a flow control valve for suppressing left steering so that the pressure oil flow rate decreases.
The flow control valve for suppressing the right steering is provided with a driving means.
To reduce the left steering
The control flow control valve is a pressure oil flow for generating right steering assist force.
A vehicle steering system characterized in that it does not reduce the quantity . 8. The right steering suppression signal is output in the right steering direction.
Transmitted when the cause of steering suppression is detected, and the left steering suppression signal
Is transmitted by detecting the cause of steering suppression in the left steering direction.
The vehicle steering system according to claim 7 . 9. The control valve is a high pressure oil having a pressure corresponding to a steering force.
Can be guided to a hydraulic actuator,
Each flow control valve generates steering assist force according to the pressure of the pressure oil.
8. The pressure oil flow rate for reducing the flow rate can be reduced.
Alternatively, the vehicle steering system according to Item 8 . 10. Each pressure control valve comprises a pressure-sensitive chamber and the pressure-sensitive chamber.
And a valve member that moves according to the hydraulic pressure in
The control valve drive means has an oil passage switching valve, and each switching
The valve is commonly used when the pressure sensitive chamber is connected to the high pressure side by the steering suppression signal.
The pressure sensitive chamber is connected to the low pressure side by releasing the steering suppression signal to
Steering according to the amount of movement of the valve member according to the pressure in the pressure sensitive chamber
The vehicle steering system according to claim 9 , wherein the flow rate of the pressure oil for generating the assisting force is reduced . 11. When driving one of the flow rate control valves
In addition, the pressure oil flow rate for generating the steering assist force is minimized.
The high pressure supplied to the driven flow control valve
A means for returning the pressure oil to the low pressure side is provided.
10. The vehicle steering system according to any one of 10 to 10 . 12. A means for suppressing steering by a driver is provided.
The steering system of the equipped vehicle is operated with or without steering.
A state in which the rudder suppression force can be applied and a state in which it can be released
To the steering mechanism including the steering wheel.
The steering assist force is applied when steering with the steering wheel.
Motor and the target control value corresponding to the given input signal.
Control for driving the motor using the target control value of
Means and a sensor for detecting a traveling state of the vehicle and outputting a traveling state signal.
A danger prediction signal is output due to the approach of the vehicle, obstacle, and vehicle.
Between the danger predicting means to be applied and the sensor and the danger predicting means and the drive control means
Connected and given a danger prediction signal from the danger prediction means
When not in use, the running condition signal given by the sensor is
As it is given as an input signal to the drive control means, predicting danger
When the danger prediction signal is given from the means,
The driving condition signal given by the service to the content of the danger prediction signal
The driving state signal is changed according to the driving control means.
Safety control means for avoiding danger to be given as an input signal to
And a steering device for a vehicle. 13. The direction of the vehicle in which the danger prediction signal is transmitted.
The safety control means includes a signal indicating whether or not an obstacle is approaching,
The target system that prohibits vehicles from moving toward obstacles
It is characterized by changing to a running state signal corresponding to the control value
The vehicle steering system according to claim 12 .