JPH1134895A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering device high in safety and small in size, produced at a low cost, and smoothly changed from an automatic steering mode to a general steering mode. SOLUTION: An auxiliary hydraulic actuator 50 generates an operation force for a first control valve 23 according to the differential pressure between the oil pressure in a right steering oil chamber and the oil pressure of a left steering oil chamber by the hydraulic control of the pressure oil from a pump 37 by a second control valve 23' operated based on an external signal. A hydraulic cylinder 18 generates a steering auxiliary force for the general steering by the hydraulic control by the first control valve 23 operated based on the steering force of a driver and a hydraulic actuator 18 generates the steering force for an automatic steering by the hydraulic control by the first control valve 23 operated based on the generation force of the auxiliary hydraulic actuator 50. The right steering oil chamber and the left steering oil chamber are short- circuited by the operation of the steering force of the driver in the automatic steering mode so as to be switched to the general steering mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device capable of automatically steering a vehicle in response to an external signal.

[0002]

2. Description of the Related Art In recent years, there has been developed a steering device that generates a steering force according to an external signal by an actuator mounted on a vehicle and automatically steers the vehicle based on the steering force. ing.

[0003] Such a steering device can select between a normal steering mode in which the vehicle is steered based on the steering force of the driver and an automatic steering mode in which the vehicle is steered based on the steering force generated by the hydraulic actuator. An actuator which generates a steering assist force in a normal steering mode by an actuator has been proposed (Japanese Patent Laid-Open No. 7-2058).
No. 24). In this conventional steering device, when disconnection occurs in the automatic steering mode, it is possible to switch to the normal steering mode, and fail-safe is achieved.

[0004] However, in the conventional steering apparatus described above, the driver cannot change the steering direction on his own will against automatic steering. For this reason, fail-safe measures against control system abnormalities other than disconnection and unexpected emergency situations have not been sufficient.

[0005] Assuming that the driver can change the steering direction by his / her own will against automatic steering, a steering device capable of switching to the normal steering mode by applying a steering force by the driver in the automatic steering mode. (JP-A-4-39167, JP-A-4-95575).

In the steering apparatus disclosed in Japanese Patent Laid-Open Publication No. 4-39167, a steering shaft is rotated by a servomotor to generate a steering force during automatic steering. Therefore, the structure becomes complicated and the device becomes large. It is also very expensive.

In the steering apparatus disclosed in Japanese Patent Application Laid-Open No. 4-95575, a hydraulic control valve for generating a steering force during automatic steering and a hydraulic control valve for generating a steering assist force during normal steering are provided. Are provided in parallel and selectively supply pressure oil sent from a pump to each hydraulic control valve by a switching valve.

As described above, when a hydraulic control valve for generating a steering force during automatic steering and a hydraulic control valve for generating a steering assist force during normal steering are provided, the structure becomes complicated and the device becomes larger. I do. Further, it is difficult to smoothly switch the flow of the pressure oil when switching from the automatic steering mode to the normal steering mode, and a shock is given to the driver at the time of switching.

Further, there is a system in which when a driver operates a steering wheel to apply a steering force during automatic steering, the operation of the steering wheel is electrically detected and an electric signal is output to cancel the automatic steering. However, there is a possibility that the operation of the steering wheel cannot be detected or an erroneous detection may occur due to a failure of the detecting means of the operation of the steering wheel, the control device, or an electric disturbance. Therefore, there is a problem that the automatic steering is not released even if the steering wheel is operated, or the automatic steering is released against the driver's intention.

An object of the present invention is to provide a steering device that can solve the above-mentioned problem.

[0011]

According to the present invention, a normal steering mode in which a vehicle is steered based on a driver's steering force and a steering assist force generated by a hydraulic actuator, and the hydraulic actuator is generated in response to an external signal. The present invention is applied to a steering device capable of selecting an automatic steering mode in which a vehicle is steered based on a steering force. According to the present invention, in the steering device, a pressure oil supply pump, an auxiliary hydraulic actuator having a right steering oil chamber and a left steering oil chamber, an action of a driver's steering force, and the auxiliary hydraulic actuator are generated. A first control valve that is operated based on any of the action of force, and a second control valve that is operated based on an external signal thereof. In a normal steering mode, the hydraulic pressure of the hydraulic oil supplied from the pump is provided. Is controlled by the first control valve that is operated based on the driver's steering force, so that a steering assist force corresponding to the operation amount is generated by the hydraulic actuator, and is supplied from the pump in the automatic steering mode. The hydraulic pressure of the hydraulic oil is controlled by the second control valve, so that the force for operating the first control valve is supplemented according to the differential pressure between the hydraulic pressure of the right steering oil chamber and the hydraulic pressure of the left steering oil chamber. The hydraulic pressure of the hydraulic oil generated by the hydraulic actuator and supplied from the pump is controlled by the first control valve that is operated based on the force generated by the auxiliary hydraulic actuator, so that the steering according to the operation amount is performed. The right steering oil chamber and the left steering oil chamber are driven by the driver's steering force so that the force is generated by a hydraulic actuator and can be switched to the normal steering mode by applying the driver's steering force in the automatic steering mode. Characterized in that a means for short-circuiting is provided.

According to the configuration of the present invention, in the normal steering mode, the first operation is performed based on the steering force of the driver.
The hydraulic actuator generates a steering assist force for normal steering by controlling the hydraulic pressure of the pressure oil supplied from the pump by the control valve. In the automatic steering mode, the hydraulic pressure of the pressure oil supplied from the pump is controlled by a second control valve that operates based on an external signal, so that the auxiliary hydraulic actuator is driven by the oil pressure of the right steering oil chamber and the left steering oil chamber. A force for operating the first control valve is generated in accordance with the differential pressure of the hydraulic pressure of the first control valve.
The hydraulic actuator generates a steering force for automatic steering by controlling the hydraulic pressure of the pressure oil supplied from the pump by the first control valve that is operated based on the force generated by the auxiliary hydraulic actuator. When the driver applies a steering force in the automatic steering mode, the right steering oil chamber and the left steering oil chamber of the auxiliary hydraulic actuator are short-circuited. As a result, the differential pressure between the oil pressure in the right steering oil chamber and the oil pressure in the left steering oil chamber becomes zero, so that the auxiliary hydraulic actuator does not generate a force for operating the first control valve. Therefore, the hydraulic pressure of the hydraulic oil supplied from the pump is controlled by the first control valve that is operated only by the steering force of the driver, and the hydraulic actuator generates a steering assist force for normal steering. That is, in the automatic steering mode, the mode is switched to the normal steering mode by applying the steering force of the driver. Thus, the driver can surely change the steering direction by his / her own will against automatic steering, and can achieve a sufficient fail-safe function.

Further, according to the configuration of the present invention, the first control valve controls the hydraulic pressure of the pressure oil supplied from the pump, thereby generating a steering force during automatic steering and generating a steering assist force during normal steering. Can be done. That is, since a hydraulic control valve for generating a steering force during automatic steering and a hydraulic control valve for generating a steering assist force during normal steering are not separately required, the structure can be simplified and the device can be downsized. .

A steering device according to the present invention includes an input shaft and an output shaft for a driver's steering force, and both shafts are elastically connected to each other so as to be relatively rotatable in accordance with the driver's steering force. The valve has a first valve member and a second valve member, and one of the two valve members is connected to one of the two shafts elastically and relatively rotatably in response to a force generated by an auxiliary hydraulic actuator. The other of the valve members is rotatable together with the other of the two shafts, and the relative rotation amount of the two valve members is set as the operation amount of the first control valve, and acts on the hydraulic actuator in accordance with the relative rotation amount of the two valve members. The hydraulic pressure is controllable, and the auxiliary hydraulic actuator is displaceably provided on one of the two shafts to which one of the two valve members is elastically connected to be relatively rotatable. A moving member, the right steering oil chamber and the left steering oil chamber partitioned by the moving member, and a connecting member connecting the moving member to one of the two valve members. The hydraulic pressure can be selectively applied to the steering oil chamber and the left steering oil chamber, and the displacement of the moving member due to the differential pressure between the hydraulic pressure of the right steering oil chamber and the hydraulic pressure of the left steering oil chamber. Is transmitted to one of the two valve members via the connecting member, so that the two valve members can be rotated relative to each other, and a bypass oil passage connecting the right steering oil chamber and the left steering oil chamber is provided. And a normally closed on-off valve for the bypass oil passage, and the on-off valve and the two shafts are opened so that the bypass oil passage is opened by the on-off valve by the relative rotation of the two shafts according to the steering force of the driver. Are preferably linked Thereby, during the automatic steering, one of the two valve members resiliently rotates relative to one of the two shafts by the action of the force generated by the auxiliary hydraulic actuator, and the two valve members relatively rotate by the relative rotation. Thus, the first control valve is operated. A steering force corresponding to the operation amount of the first control valve is generated by a hydraulic actuator. During this automatic steering, both shafts are relatively elastically rotated by the action of the driver's steering force. By opening the bypass oil passage by the relative rotation of the two shafts, the right steering oil chamber and the left steering oil chamber are short-circuited. Thereby, the automatic steering can be released by the action of the driver's steering force as described above. That is, with a simple configuration, it is possible to smoothly switch from the automatic steering mode to the normal steering mode.

The open / close valve has a spool rotatably inserted into one of the two shafts so as to open and close the bypass oil passage. The rotation of the two shafts with respect to the other is accelerated by the spool. Preferably, a means for transmitting the information is provided. Thus, even if the two shafts are slightly rotated relative to each other in accordance with the steering force, the rotation can be accelerated and transmitted to the spool. Therefore, it is possible to reliably open the bypass oil passage by the spool and switch from the automatic steering mode to the normal steering mode.

In the steering apparatus of the present invention, the input shaft and the output shaft are coaxially connected, the first valve member is cylindrical, and the second valve member is coaxially opposed to the first valve member. The first valve member is rotatably inserted, and recesses along the axial direction are formed on the inner periphery of the first valve member and the outer periphery of the second valve member at intervals in the circumferential direction. A portion between the edge along the axis and the edge along the axial direction of the second valve member-side concave portion is a throttle portion provided in an oil passage between the hydraulic actuator and the pump, and the opening degree of the throttle portion is determined by the two valve members. It is preferable that the hydraulic pressure of the pressure oil supplied to the hydraulic actuator is controlled according to the change due to the relative rotation. Thereby, the auxiliary actuator can be configured compactly in the transmission system of the steering force.

In the steering device of the present invention, the first
Preferably, a second control valve is provided between the control valve and the tank. Thus, the hydraulic control system for automatic steering can be arranged downstream of the hydraulic control system for normal steering, so that when the automatic steering mode is changed to the normal steering mode, the flow of the pressure oil is smoothly changed. Can prevent the driver from being shocked. Further, the configuration of the hydraulic circuit is simplified.

[0018]

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

A rack and pinion type steering apparatus 1 shown in FIG. 1 has an input shaft 2 connected to a steering wheel (not shown), and an output shaft 4 coaxially connected to the input shaft 2 via a torsion bar 3. And The torsion bar 3 is connected to the input shaft 2 via a pin 5 and to the output shaft 4 via a serration 6. Thereby, the input shaft 2 and the output shaft 4 can be relatively rotated elastically according to the steering force of the driver. A pinion 7 is formed on the output shaft 4, and steering wheels (not shown) are connected to each end of the rack 8 that meshes with the pinion 7. The input shaft 2 is supported by a valve housing 10 a via a bearing 9 and is supported by an output shaft 4 via a bush 11. The output shaft 4 is connected to the rack housing 10 via bearings 12 and 13.
b.

In a normal steering mode in which the vehicle is steered based on a driver's steering force and a steering assist force generated by a hydraulic cylinder 18 described later, the input shaft 2 is rotated by a steering torque based on the driver's steering force. The rotation of the input shaft 2 is transmitted to the pinion 7 via the torsion bar 3. The rack 8 moves in the axial direction by the rotation of the pinion 7. The wheels are steered by the movement of the rack 8. Oil seals 14 and 15 are provided between the input shaft 2 and the valve housing 10a and between the output shaft 4 and the rack housing 10b. A support yoke 16 for supporting the rack 8 is provided. The support yoke 16 is pressed against the rack 8 by the elastic force of a spring 17.

In the automatic steering mode, a steering force is generated,
A hydraulic cylinder 18 is provided as a hydraulic actuator that generates a steering assist force in a normal steering mode.
The hydraulic cylinder 18 has a cylinder tube constituted by a rack housing 10b and a piston 20 integrated with the rack 8, and a first oil chamber 21 and a second oil chamber 22 partitioned by the piston 20. Have.

Each of the oil chambers 21 and 22 is connected to a rotary hydraulic first control valve 23 which is operated based on both the action of a driver's steering force and the action of a force generated by an auxiliary hydraulic actuator 50 described later. Is done. The first control valve 23
The hydraulic pressure of the pressure oil supplied from the pump 37 is controlled in accordance with the operation amount of.

That is, the first control valve 23 includes a cylindrical first valve member 24 and a second valve member 25 which is coaxially rotatably inserted into the first valve member 24. The first valve member 24 is inserted into the valve housing 10a so as to be relatively rotatable, and is coaxially and elastically connected to the output shaft 4 so as to be relatively rotatable as described later. The second valve member 25 is integrally formed on the outer periphery of the input shaft 2 and rotates together with the input shaft 2. Thereby, the torsion bar 3 is twisted by the steering torque based on the steering force of the driver, and the two shafts 2,
The first valve member 24 is elastically rotated relative to the first valve member 24.
And the second valve member 25 rotate relative to each other. The amount of relative rotation between the two valve members 24 and 25 is the amount of operation of the first control valve 23.

The hydraulic pressure acting on the hydraulic cylinder 18 is controlled according to the relative rotation amount of the two valve members 24 and 25. That is, as shown in FIG. 2, a plurality of concave portions along the axial direction are formed at equal intervals in the circumferential direction on the inner periphery of the first valve member 24 and the outer periphery of the second valve member 25. The first valve member-side concave portion includes a right steering concave portion 27 and a left steering concave portion 28 which are located at equal intervals in the circumferential direction. The second valve member side recess is composed of a pressure oil supply recess 29 and a pressure oil discharge recess 30 which are located at equal intervals in the circumferential direction. Each right steering recess 27 and each left steering recess 28 are alternately arranged in the circumferential direction, and each pressure oil supply recess 29 and each pressure oil discharge recess 30 are alternately arranged in the circumferential direction.

Each right steering recess 27 is provided with a first valve member 2.
4 and the first flow passage 31 formed in the valve housing 1
0a from the first port 32 formed in the hydraulic cylinder 1
8 to the first oil chamber 21.

Each left steering recess 28 is provided with the first valve member 2.
2 and the second flow path 33 formed in the valve housing 1
0a from the second port 34 formed in the hydraulic cylinder 1
8 to the second oil chamber 22.

Each pressure oil supply recess 29 is provided with a third flow passage 35 formed in the first valve member 24 and the valve housing 1.
It communicates with a pump 37 via an inlet port 36 formed at 0a.

Each pressure oil discharge recess 30 is formed in a first discharge passage 38 formed in the second valve member 25, a 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 via the formed second discharge path 39 and a second control valve 23 'described later.

Thus, the oil chambers 21 and 22 of the hydraulic cylinder 18 and the pump 37 are connected via the inter-valve oil passage 42 formed between the inner and outer circumferences of the first valve member 24 and the second valve member 25. Connected. In the inter-valve oil passage 42, between the first valve member-side concave portion and the second valve member-side concave portion, there are throttle portions A, B, C, and D whose opening degree changes due to the relative rotation of the two valve members 24 and 25. Is done. Each of the apertures A, B, C,
By changing the opening of D, the hydraulic pressure acting on the hydraulic cylinder 18 is controlled.

FIG. 2 shows the relative positions of the two valve members 24 and 25 at the straight steering position where steering is not performed. In this state, the openings of the throttle portions A, B, C, and D between the pressurized oil supply recesses 29 and the pressurized oil discharge recesses 30 are constant, and the pressurized oil flows through the respective throttle portions A, B, C and D return to the tank 41 from the second discharge path 39 via the second control valve 23 '.

When the vehicle is steered to the right from the straight steering position, the relative rotation of the first valve member 24 with respect to the output shaft 4 due to the torsion of the torsion bar 3 corresponding to the driver's steering torque or the force generated by the auxiliary hydraulic actuator 50 described later. Accordingly, the two valve members 24 and 25 rotate relative to each other. In accordance with the relative rotation amount, each right steering recess 27
The opening degree of the throttle portion A between the pressure oil supply concave portion 29 and the throttle portion B between the left steering concave portion 28 and the pressure oil discharge concave portion 30 increases, and the left steering angle increases. Of the throttle portion C between the pressure recess 28 and each pressure oil supply recess 29 and the throttle portion D between each right steering recess 27 and each pressure oil discharge recess 30.
Is smaller. As a result, the first
The pressurized oil is supplied to the oil chamber 21 and the tank 4
The oil is returned to the rack 1 and the steering assist force to the right of the vehicle is applied to the rack 8 during normal steering, and the steering force to the right of the vehicle is applied to the rack 8 during automatic steering.

When the vehicle is steered to the left from the straight steering position, the opening of each of the throttle portions A, B, C, and D changes in reverse to the case where the vehicle is steered to the right. Therefore, during normal steering, the vehicle is steered to the left. At the time of automatic steering, the steering force to the left of the vehicle acts on the rack 8 during automatic steering.

As shown in FIGS. 1, 3 to 5, an auxiliary hydraulic actuator 50 is provided. The auxiliary hydraulic actuator 50 includes a moving member 53 provided to be displaceable on the output shaft 4, a right steering oil chamber 51 and a left steering oil chamber 52 partitioned by the moving member 53, and a moving member 53 including a first valve. It has a connecting member 54 connected to the member 24. In the present embodiment, a pair of recesses 4a is provided on the outer periphery of one end (the upper end in FIG. 1) of the output shaft 4.
4b is formed, and annular member 55 covering both recesses 4a, 4b
Are fitted to the output shaft 4. As a result, the interior of both recesses 4a and 4b is used as the oil chambers 51 and 52. Further, two oil chambers 51 and 52 are provided at one end of the output shaft 4.
Is formed, and the substantially cylindrical moving member 53 is inserted into the through hole 56 so as to be movable in the axial direction.
The moving member 53 has a circumferential groove 53a formed on the outer periphery, and each end faces the pressing plate 53b. Each holding plate 53b
Needle 53c is attached to the end, and each oil chamber 51, 5
By being fitted into the guide grooves 51a and 52a formed on the inner surface of the second member 2, the movable member 53 can be moved in the axial direction.

In the present embodiment, the first valve member 24 is elastically connected to the output shaft 4 via the moving member 53 so as to be relatively rotatable. That is, each oil chamber 51,
The leaf springs 58 and 59 are provided on the inner surface of the
3 are attached so as to be in contact with both ends via a needle 53c and a pressing plate 53b. The connecting member 54 has a round bar shape, one end of which is fixed to the center of the outer periphery of the moving member 53, and the other end of which is inserted into a notch 24 a formed at the lower end of the first valve member 24. The moving direction of the moving member 53 is parallel to the tangential direction of the peripheral surface of the first valve member 24 in a plane perpendicular to the axis of the output shaft 4. When the torsion bar 3 is twisted according to the steering torque based on the steering force of the driver, the friction between the first valve member 24 and the second valve member 25 and the first valve member 2
The rotation of the first valve member 24 following the second valve member 25 in accordance with the friction between the valve member 4 and the valve housing 10a is prevented by the preload of the leaf springs 58 and 59. Thereby, both valve members 24, 2
5 is rotated relative to the driver's steering force,
The moving member 53 is prevented from accidentally moving from the neutral position in the normal steering mode. In the automatic steering mode, the first valve member 24 rotates relative to the output shaft 4 by moving the moving member 53 from the neutral position, and the right steering oil chamber is moved by moving the moving member 53 in one direction. The leaf spring 58 of the left steering oil chamber 52 is elastically deformed by the movement in the other direction.
That is, the movement of the moving member 53 allows the two valve members 24 and 25 to be relatively rotated elastically.
Note that the first valve member 24 and the output shaft 4 are connected to each other without the moving member 53, for example, by the first valve member 24.
And the output shaft 4 may be elastically connected to each other via springs which are individually joined to each other.

The right steering oil chamber 51 and the left steering oil chamber 52 are described.
Is connected to the second control valve 23 'as shown in FIG. The second control valve 23 ′ is provided between the first control valve 23 and the tank 41,
Control the hydraulic pressure acting on zero.

The second control valve 23 'is inserted into an auxiliary valve housing 61 connected to the valve housing 10a and an insertion hole 66 of the auxiliary valve housing 61 so as to be movable in the axial direction (vertical direction in FIG. 1). Spool 62 and a screw member 6 screwed to the spool 62
And 4. The axis of the spool 62 and the screw member 64
Are parallel to the relative rotation axes of the two valve members 24 and 25 and are eccentric to each other. One end of the insertion hole 66 is closed by a plug 68, and the other end is closed by a cover 94. A compression coil spring 90 is arranged between the spool 62 and the plug 68. The output shaft of the stepping motor 80 is connected to the screw member 64.

The stepping motor 80 is connected to the controller 8
In the automatic steering mode, the screw member 64 is driven to rotate in one direction during right steering and is driven to rotate in the other direction during left steering. The rotation of the screw member 64 during right steering causes the spool 62 to be displaced downward in the drawing, and the rotation during left steering causes the spool 62 to be displaced upward in the drawing. The spool 6
The decentering of the axis of the second member and the axis of the screw member 64 prevents the rotation of the spool 62.

The control device 81 is constituted by a computer, and is connected to an external signal receiver 85 and a steering amount sensor 86. The external signal may be, for example, a vehicle guidance signal transmitted from a transmitter provided on a traveling road or a guardrail, or an alarm signal which notifies a collision danger transmitted from a transmitter provided in another vehicle. Can be. The steering amount sensor 86 detects an amount corresponding to the actual steering amount, such as the amount of movement of the rack 8 and the rotation angle of the steering wheel.

The control device 81 outputs the following control signal in the automatic steering mode, and the output of the control signal is released in the normal steering mode. Switching between the automatic steering mode and the normal steering mode is performed by operating a switch (not shown).

First and second circumferential grooves 62a and 62b are formed at two places on the outer circumference of the spool 62, and third, fourth and fifth circumferential grooves 66a, 66b and 66 are formed at three places on the inner circumference of the insertion hole 66.
c is formed. The second circumferential groove 62b and the fifth circumferential groove 66c
Between the first circumferential groove 62a and the fourth
A second constricted portion B 'is defined between the peripheral groove 66b and the third constricted portion C' is defined between the first peripheral groove 62a and the third peripheral groove 66a. The gap between the peripheral groove 66b is the fourth
The aperture portion is D '.

The first circumferential groove 62a is provided between the auxiliary valve housing 61 and the oil passage 7 formed in the valve housing 10a.
0, 71, a circumferential groove 4d formed on the outer periphery of the output shaft 4, and an oil passage 72 formed in the output shaft 4 to the left steering oil chamber 52 of the auxiliary hydraulic actuator 50. . The second circumferential groove 62b is provided with oil passages 73 and 74 formed in the auxiliary valve housing 61 and the valve housing 10a, a space 4e formed between the output shaft 4 and the oil seal 10b, and an output shaft The oil passage 75 communicates with the right hydraulic oil chamber 51 of the auxiliary hydraulic actuator 50 through the oil passage 75 formed in the auxiliary hydraulic actuator 50. The third and fifth circumferential grooves 66a and 66c are provided in the oil passage 7 formed in the auxiliary valve housing 61 and the valve housing 10a.
6, 77, 78 and the second discharge path 39 of the first control valve 23, and the pump 37 through the first control valve 23.
Lead to. The fourth circumferential groove 66b is connected to the tank 41 via a discharge port 79 formed in the auxiliary valve housing 61.
Lead to. As a result, each of the oil chambers 51 and 52 of the auxiliary hydraulic actuator 50 is connected to the pump 3 via the second control valve 23 '.
7 are connected to form the hydraulic circuit shown in FIG.

The degree of opening of the first to fourth throttle portions A ', B', C ', D' of the second control valve 23 'is determined based on an external signal input via the receiver 85. Reference numeral 81 outputs a control signal for the motor 80, and changes when the second control valve 23 'is operated. The pressure oil supplied from the pump 37 is controlled by the second control valve 23 'by the change in the opening degree.
As a result, the hydraulic pressure is applied to the right steering oil chamber 51 and the left steering oil chamber 52 of the auxiliary hydraulic actuator 50, and a force for operating the first control valve 23 is generated by the auxiliary hydraulic actuator 50. You.

FIG. 1 shows the position of the spool 62 of the second control valve 23 'at the straight steering position where steering is not performed. In this state, the opening degrees of the first to fourth throttle portions A ', B', C ', D' are constant, and the pump 3
7 is supplied to the second control valve 23 'through the first control valve 23, and flows back to the tank 41 through each of the throttle portions A', B ', C', and D '. 50 does not generate any force.

In the automatic steering mode, when an external signal is input to the control device 81 via the receiver 85, the control device 81 controls the actual steering amount input from the steering amount sensor 86 and the steering based on the external signal. The control signal is output to the motor 80 so that the actual steering amount becomes the steering amount based on the external signal.

When the control device 81 outputs a control signal for steering rightward from the straight steering position to the motor 80, the motor 80 rotates the screw member 64 so that the spool 62 is rotated.
Are displaced downward in FIG. Due to this displacement, the first
The opening of the throttle A 'and the opening of the second throttle B' increase, and the opening of the third throttle C 'and the opening of the fourth throttle D' decrease. As a result, pressure oil according to the external signal is supplied from the pump 37 to the right steering oil chamber 51 of the auxiliary hydraulic actuator 50, and the oil is returned from the left steering oil chamber 52 to the tank 41.

When pressure oil is supplied to the right steering oil chamber 51 of the auxiliary hydraulic actuator 50, its movement is caused by the pressure difference between the right steering oil chamber 51 and the left steering oil chamber 52. The member 53 is a leaf spring 59 of the left steering oil chamber 52.
Is displaced so as to be elastically deformed. This displacement is transmitted to the first valve member 24 via the connecting member 54, and the force for relatively rotating the first valve member 24 and the second valve member 25 elastically so that a right steering force is generated. Occur. That is, the first control valve 23 is operated based on the force generated by the auxiliary hydraulic actuator 50, and the hydraulic pressure of the pressure oil supplied from the pump 37 is controlled by the first control valve 23 as described above. Pressure oil is supplied from 37 to the first oil chamber 21 of the hydraulic cylinder 18, and a rightward steering force of the vehicle acts on the rack 8.

When the control device 81 outputs a control signal for steering leftward from the straight steering position to the motor 80, the motor 80 rotates the screw member 64 to rotate the spool 62.
Are displaced upward in FIG. Due to this displacement, the first
The opening of the throttle A 'and the opening of the second throttle B' are reduced, and the opening of the third throttle C 'and the opening of the fourth throttle D' are increased. As a result, pressure oil corresponding to the external signal is supplied from the pump 37 to the left steering oil chamber 52 of the auxiliary hydraulic actuator 50, and the oil is recirculated from the right steering oil chamber 51 to the tank 41.

When the pressure oil is supplied to the left steering oil chamber 52 of the auxiliary hydraulic actuator 50, the hydraulic oil is moved by the pressure difference between the right steering oil chamber 51 and the left steering oil chamber 52. The member 53 is a leaf spring 58 of the right steering oil chamber 51.
Is displaced so as to be elastically deformed. When this displacement is transmitted to the first valve member 24 via the connecting member 54, a force for relatively rotating the first valve member 24 and the second valve member 25 relatively to generate a left steering force is generated. Occur. That is, the first control valve 23 is operated based on the force generated by the auxiliary hydraulic actuator 50, and the hydraulic pressure of the pressure oil supplied from the pump 37 is controlled by the first control valve 23 as described above. Pressure oil is supplied from 37 to the second oil chamber 22 of the hydraulic cylinder 18, and a steering force to the left of the vehicle acts on the rack 8.

Thus, while the control signal is being output by the control device 81, the automatic steering mode is set in which the vehicle is steered based on the steering force generated by the hydraulic cylinder 18 in response to the external signal.

In the automatic steering mode, the right steering oil chamber 51 and the left steering oil chamber 52 are short-circuited by the driver's steering force so that the normal steering mode can be switched by applying the driver's steering force. Means are provided. That is, as shown in FIGS. 1 and 3 to 7, a bypass oil passage 101 is provided in the output shaft 4 so as to connect the right steering oil chamber 51 and the left steering oil chamber 52. A normally closed on-off valve 102 for opening and closing the oil passage 101 is provided.

The open / close valve 102 is connected to the output shaft 4.
And a cylindrical spool 103 rotatably inserted so as to open and close the bypass oil passage 101. The rotation axis of the spool 103 is parallel to the axes of the input / output shafts 2 and 4. A pair of recesses 103a and 103b located on opposite sides of the spool 103 are formed on the outer periphery of the spool 103, and a through hole 1 connecting the recesses 103a and 103b is provided.
03c is formed. No driver's steering force,
When the input shaft 2 and the output shaft 4 are not relatively rotating, the spool 103 closes the bypass oil passage 101 as shown in FIG.

The open / close valve 102 is connected to the input / output valve 102 so that the bypass oil passage 101 is opened by the open / close valve 102 by elastic relative rotation of the shafts 2 and 4 via the torsion bar 3 according to the steering force of the driver. It is interlocked with the shafts 2 and 4. That is, the spool 103
A gear 105 is integrated with one end of the input shaft 2 and a sector gear 106 meshing with the gear 105 is integrated with the input shaft 2. Accordingly, the rotation of the sector gear 106 is transmitted to the gear 105 by the relative rotation of the input shaft 2 and the output shaft 4, and the spool 103 rotates. The gear ratio between the gear 105 and the sector gear 106 is set such that the rotation of the input shaft 2 with respect to the output shaft 4 is transmitted to the spool 103 at an increased speed. FIG. 8 shows a state in which the spool 103 is rotated by the relative rotation of the two output shafts 4 by the right steering force of the driver, and the bypass oil passage 101 is opened. FIG. 9 shows a state in which the spool 103 is rotated by the relative rotation of the two output shafts 4 due to the driver's left steering force, and the bypass oil passage 101 is opened.

According to the above configuration, in the normal steering mode, the hydraulic pressure of the hydraulic oil supplied from the pump 37 is controlled by the first control valve 23 which is operated based on the steering force of the driver, so that the hydraulic cylinder is controlled. Reference numeral 18 generates a steering assist force for normal steering. In the automatic steering mode,
The hydraulic pressure of the pressure oil supplied from the pump 37 is controlled by the second control valve 23 ′ that operates based on an external signal,
The auxiliary hydraulic actuator 50 controls the first control valve 2 according to the pressure difference between the oil pressure in the right steering oil chamber 51 and the oil pressure in the left steering oil chamber 52.
3 to generate a force. The first control valve 2 operated based on the force generated by the auxiliary hydraulic actuator 50
By 3, the hydraulic pressure of the pressure oil supplied from the pump 37 is controlled, and the hydraulic cylinder 18 generates a steering force for automatic steering. In other words, the first valve member 24 is elastically relatively rotated with respect to the output shaft 4 by the action of the force generated by the auxiliary hydraulic actuator 50, and the two valve members 24 and 25 are relatively rotated by the relative rotation. The first control valve 23 is operated. A steering force corresponding to the operation amount of the first control valve 23 is generated by the hydraulic cylinder 18. In the automatic steering mode, when the driver applies a steering force, the right steering oil chamber 51 and the left steering oil chamber 52 of the auxiliary hydraulic actuator 50 are short-circuited.
That is, the shafts 2 and 4 are elastically rotated relative to each other by the action of the driver's steering force, and the bypass oil passage 101 is opened by the relative rotation, so that the right steering oil chamber 51 and the left steering oil chamber 52 are separated. Is short-circuited. As a result, the differential pressure between the oil pressure in the right steering oil chamber 51 and the oil pressure in the left steering oil chamber 52 becomes zero, so that the moving member 53 returns to the neutral position, and the auxiliary hydraulic actuator 50 operates the first control valve. No actuation force is generated. Therefore, by the first control valve 23 that is operated only by the steering force of the driver,
Since the hydraulic pressure of the pressure oil supplied from the pump 37 is controlled, the hydraulic cylinder 18 generates a steering assist force for normal steering. That is, in the automatic steering mode, the automatic steering can be quickly released only by applying the steering force of the driver, and the mode is switched to the normal steering mode. Thus, the driver can surely change the steering direction by his / her own will against automatic steering, and can achieve a sufficient fail-safe function. Further, it is possible to smoothly switch from the automatic steering mode to the normal steering mode with a simple configuration. Further, in the above configuration, even if the two shafts 2 and 4 slightly rotate relative to each other in accordance with the steering force, the rotation can be accelerated and transmitted to the spool 103 of the open / close valve 102. As a result, the bypass oil passage 101 is reliably opened by the spool 103, and the automatic steering mode can be switched to the normal steering mode. Further, when the driver's steering force is released, the torsion of the torsion bar 3 is released, so that the spool 103 returns to the closed position of the bypass oil passage 101.

By controlling the hydraulic pressure of the pressure oil supplied from the pump 37 by the first control valve 23, a steering force can be generated during automatic steering and a steering assist force can be generated during normal steering. That is, since a hydraulic control valve for generating a steering force during automatic steering and a hydraulic control valve for generating a steering assist force during normal steering are not separately required, the structure can be simplified and the device can be downsized. .

Further, a second control valve 23 'is provided between the first control valve 23 and the tank 41, and both valves 23 and 23' are arranged in series, so that a hydraulic control system for automatic steering is provided. It can be arranged downstream of the hydraulic control system for normal steering, and when changing the automatic steering mode to the normal steering mode, the flow of pressure oil can be changed smoothly and it can prevent shock to the driver .

Further, the auxiliary hydraulic actuator 50 for the automatic steering mode can be made compact in the steering force transmission system.

The present invention is not limited to the above embodiment. For example, the first valve member is rotatable together with the output shaft, the second valve member is elastically connected to the input shaft so as to be relatively rotatable, and the input shaft and the second shaft member are generated by an auxiliary hydraulic actuator provided on the input shaft. The valve member may be relatively rotated. Further, the second valve member may have a cylindrical shape, and the first valve member may be inserted into the second valve member. The present invention is also applicable to a ball screw type steering device.

[0058]

According to the present invention, in a steering device capable of selecting an automatic steering mode or a normal steering mode, safety is improved, the device is reduced in size, the structure is simplified, and the manufacturing cost is reduced. The automatic steering mode can be reliably and smoothly changed from the normal steering mode to the normal steering mode, and the shock acting on the driver at the time of the change can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a steering device according to an embodiment of the present invention.

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

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a view taken in the direction of the arrow IV in FIG. 3;

FIG. 5 is a view taken in the direction of the arrow V in FIG. 3;

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

FIG. 7 is a sectional view showing an opening / closing valve of the steering device according to the embodiment of the present invention;

FIG. 8 is a sectional view of a main part in a state where a right steering force is applied.

FIG. 9 is a sectional view of a main part in a state where a left steering force is applied.

[Explanation of symbols]

 2 Input Shaft 4 Output Shaft 18 Hydraulic Cylinder 23 First Control Valve 23 'Second Control Valve 24 First Valve Member 25 Second Valve Member 37 Pump 41 Tank 50 Auxiliary Hydraulic Actuator 51 Right Steering Oil Chamber 52 Left Steering Oil Chamber 53 Moving member 81 Control device 85 Receiver 101 Bypass oil passage 102 Open / close valve 103 Spool 105 Gear 106 Sector gear A, B, C, D Throttle section

Claims (5)

[Claims] The vehicle is steered based on a normal steering mode in which the vehicle is steered based on a driver's steering force and a steering assist force generated by a hydraulic actuator, and a steering force generated by the hydraulic actuator in response to an external signal. A hydraulic oil supply pump, an auxiliary hydraulic actuator having a right steering oil chamber and a left steering oil chamber, an operation of a driver's steering force, A first control valve that is activated based on any of the action of the force generated by the auxiliary hydraulic actuator; and a second control valve that is activated based on an external signal thereof. The hydraulic pressure of the pressurized oil is controlled by the first control valve that is operated based on the steering force of the driver, so that a steering assist force corresponding to the amount of operation is provided by the hydraulic control. In the automatic steering mode, the hydraulic pressure of the pressure oil supplied from the pump is controlled by the second control valve, so that the force for operating the first control valve is increased by the force of the right steering oil chamber. A first hydraulic pressure is generated by the auxiliary hydraulic actuator in accordance with a pressure difference between the hydraulic pressure and the hydraulic pressure of the left steering oil chamber, and the hydraulic pressure of the pressure oil supplied from the pump is operated based on the force generated by the auxiliary hydraulic actuator. By being controlled by the control valve, a steering force corresponding to the operation amount is generated by the hydraulic actuator, and the driver is switched to the normal steering mode by applying the driver's steering force in the automatic steering mode. A steering device for short-circuiting the right steering oil chamber and the left steering oil chamber by the steering force. 2. The vehicle according to claim 1, further comprising an input shaft and an output shaft for a driver's steering force, wherein both shafts are connected to be elastically rotatable in accordance with the driver's steering force. It has a valve member and a second valve member, and one of the two valve members is connected to one of the two shafts elastically and relatively rotatably in response to the force generated by the auxiliary hydraulic actuator, and the other of the two valve members is And the other of the two shafts can be rotated together with the other, the relative rotation amount of both valve members is the operation amount of the first control valve, and the hydraulic pressure acting on the hydraulic actuator can be controlled according to the relative rotation amount of both valve members. The auxiliary hydraulic actuator includes a movable member that is displaceably provided on one of the two shafts to which one of the two valve members is elastically connected so as to be relatively rotatable. The right steering oil chamber and the left steering oil chamber, which are separated from each other, and a connecting member that connects the moving member to one of the two valve members. The right control oil chamber and the left steering are controlled by the second control valve. And the displacement of the moving member due to the pressure difference between the oil pressure of the right steering oil chamber and the oil pressure of the left steering oil chamber is controlled via the connecting member. By being transmitted to one of the valve members, the two valve members can be rotated relative to each other, and a bypass oil passage that connects the right steering oil chamber and the left steering oil chamber to each other; A normally closed on-off valve is provided, and the on-off valve and the two shafts are linked so that the bypass oil passage is opened by the on-off valve by the relative rotation of the two shafts according to the steering force of the driver. 2. The steering device according to claim 1. 3. The on-off valve has a spool rotatably inserted into one of the two shafts so as to open and close the bypass oil passage. 3. A means for transmitting at an increased speed is provided.
The steering device according to claim 1. 4. The input shaft and the output shaft are coaxially connected, the first valve member is cylindrical, and the second valve member is coaxially inserted into the first valve member so as to be relatively rotatable. An axially extending recess is formed in the inner periphery of the first valve member and the outer periphery of the second valve member at intervals in the circumferential direction. The portion between the valve member side concave portion and the edge along the axial direction is a throttle portion provided in the oil passage between the hydraulic actuator and the pump, and the opening degree of the throttle portion is changed by the relative rotation of both valve members. 3. The steering device according to claim 2, wherein the hydraulic pressure of the pressure oil supplied to the hydraulic actuator is controlled accordingly. 5. The steering apparatus according to claim 1, wherein a second control valve is provided between the first control valve and the tank.