JPH06219303A - Steering device - Google Patents

Abstract

PURPOSE:To reduce a space required for operation of a steering link device in a steering device acquiring an Ackerman characteristic in a normal steering range and having a parallel characteristic in the neighborhood of the largest steering angle. CONSTITUTION:Knuckle arms 70 of left and right steering wheels 71 are connected to each other by a steering link device 20 of Ackerman characteristic, and rotation of a steering handle 10 is transmitted to a part of the steering link device 20 through a transmission mechanism 11. A control device A is provided in such a way that an excessive steering cylinder 30 is provided between a part of the steering device 20 connected to the transmission mechanism 11 and a part connected to each Knuckle arm either one of a cylinder and a piston rod is connected to the side of the transmission mechanism 11 of the steering mechanism 11 of the steering link device 20, the other is connected to the side of the Knuckle arm 70 so as to increase the steering angle of the steering wheel to be outside in the steering direction by way of supplying working fluid to the cylinder device 30 for excessive steering near the maximum steering position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device for steering a steering wheel of an automobile.

[0002]

2. Description of the Related Art Steering devices for connecting knuckle arms that support left and right steering wheels of an automobile are roughly classified into a rigid axle suspension device and an independent suspension device.
In either case, the Ackermann characteristic is obtained in which the steering wheel on the inner side in the steering direction has a larger turning angle than the steering wheel on the outer side. By doing so, there is an advantage that the sideslip of the tire during turning of the vehicle is reduced, the tire can be smoothly turned, and the wear of the tire is reduced. However, the larger the steering angle, the larger the difference between the turning angles of the inner and outer wheels (see the solid line in FIG. 3). On the other hand, the maximum turning angle of the inner wheel is limited by the stopper to prevent it from hitting the vehicle body parts. However, there is a problem that the turning radius cannot be reduced.

In order to solve this problem, the applicant previously disclosed in Japanese Patent Laid-Open No. 4-183681 that parallels the Ackerman characteristics in the small steering angle region and the parallel angles of the inner and outer wheels are equal in the large steering angle region. We have proposed a steering link mechanism that can obtain characteristics close to those of the characteristics.

[0004]

However, in the technique disclosed in Japanese Patent Laid-Open No. 4-183681, a bell crank as well as a tie rod is used as a steering link device for connecting both steering wheels in order to obtain the characteristic. The width of the steering link device becomes large, and a large space is required due to the swing, which causes a problem of interference with other vehicle body parts.

The present invention aims to solve each of these problems.

[0006]

To this end, in the steering apparatus according to the present invention, as shown in FIGS. 1 to 10, each knuckle arm 70 that supports the left and right steering wheels 71 is located inside the steering direction. The steering link device 20 is connected to the steering wheel 71 so that the steering wheel 71 has a larger turning angle than the steering wheel 71, and the rotation of the steering wheel 10 is transmitted to a part of the steering link device 20. In the steering system including the transmission mechanism 11 for operating the cylinders 32, 42, 5
2, housings 31, 41 and 51, operating pistons 33, 43 and 53 fitted to the cylinders, and a return for biasing the operating pistons toward one end side of the housings 31, 41 and 51. One of the housings 31, 41, 51 and one of the actuating pistons 33, 43, 53 is on the part of the steering link device 20, and the other is the knuckle arm. A pair of turning-up cylinder devices 30 connected to the side of the steering link device 20 and provided in the middle of the steering link device 20 and the turning-up gear that is at least on the outer side in the steering direction when it is detected that the maximum steering position is approached. Housing 31, 41, 51 of cylinder device 30 and operating pistons 33, 43, 5
3 is provided with a control device A for supplying a working fluid in a direction in which it relatively moves against the return springs 35, 45, 55.

[0007]

The working fluid is not supplied to each of the increasing gear cylinder devices 30 until the maximum steering position is approached. Therefore, the increasing gear cylinder devices 30 are in the shortest state by the return springs 35, 45, 55. A normal Ackermann characteristic is obtained in which the steering wheel 71 on the inside has a larger turning angle than that on the outside. When approaching the maximum steering position, the control device A supplies the working fluid to at least the outside of the steering direction, so as to increase or decrease the length of the increasing cylinder device 30. Therefore, the steering wheel 71 on the outer side is rotated by the increase or decrease of the length in the direction in which the turning angle increases, and the turning angle is about the same as the steering wheel 71 on the inner side.

[0008]

As described above, according to the present invention, the Ackermann characteristic is obtained until the maximum steering position is approached, and the parallel characteristic is obtained after the maximum steering position is approached. As a result, when the vehicle is not in the vicinity of maximum steering, the sideslip of the tire when turning is less and the tire can be turned smoothly, tire wear is reduced, and the turning radius of the vehicle at maximum steering is the turning angle of the outside steering wheel. It becomes smaller by the increase.

Further, each of the increasing cylinder devices can be formed in a relatively simple cylindrical shape, and one of the housing and the actuating piston 33 is connected to the transmission mechanism of the steering link device and the other is to the knuckle arm side. Since it is connected and there is no part connected to the vehicle body, the width of the steering link device is small, and the space required for operation is also small, and the risk of causing interference with other vehicle body parts is greatly reduced To do. Therefore, the steering apparatus according to the present invention is more easily mounted on the vehicle body of an automobile than the conventional steering apparatus of this type.

[0010]

First, the first embodiment shown in FIGS. 1 to 3 will be described. In this embodiment, the present invention is applied to a circulating ball screw type front wheel steering device used in a rigid axle type suspension device. The left and right steering wheels 71 are knuckle arms 70 that are supported by the vehicle body B of the automobile so as to be steerable and rotatable.
The knuckle arms 70 are connected to each other by tie rods 21 having ball joints at both ends.
The central portion 21a of the tie rod 21 has a handle shaft 12,
It is connected to the steering wheel 10 via a transmission mechanism 11 including a circulation ball screw type gear box 13, a pitman arm 13a, a drag link 14, a lever arm 15 and a pin 15a. When the steering wheel 10 is rotated, the tie rod 21 is moved. Then, the left and right front wheels 71 are steered. When the front wheel 71 on the inner side in the steering direction reaches a predetermined maximum turning angle, the knuckle arm 70 that supports the front wheel 71 contacts the steering stopper 73 fixed to the vehicle body B to prevent the turning angle from further increasing. Prevents interference with other body parts.

The gear box 13 of the transmission mechanism 11 incorporates an integral type power steering device. The power steering system includes a supply pump 60 driven by an engine 66.
Is supplied through the check valve 65, the increased steering force is output to the pitman arm 13a, and the front wheels 71 are steered.

The tie rod 21 constituting the steering link device 20 for connecting the left and right knuckle arms 70 is divided into a central portion 21a and left and right end portions 21b, and a thickening cylinder device 30 is provided between these two portions. Has been. As will be described later, the turning-up cylinder device 30 is locked in the shortest state until the steering handle 10 is rotated to the vicinity of the maximum steering position, and in that state, the steering link device 20 gives the steering device an Ackermann characteristic. . That is, as shown by the solid line portion in FIG.
The steering wheel turning angle characteristic I of the front wheel 71 on the inner side in the steering direction with respect to the rotation angle is larger than the steering wheel turning angle characteristic O of the front wheel 71 on the outer side in the steering direction. Along with this, the difference in cutting angle between the characteristics I and O increases.

Next, the details of an example of the cylinder device 30 for additional cutting will be described with reference to FIG. Cylinder device for additional cutting 3
The housing 31 of No. 0 is composed of a cylindrical main body 31a and a lid member 31b screwed and fixed to one end of the main body 31a.
A cylinder member 32 is fitted and fixed to the intermediate portion of the inner peripheral surface of a. The operating piston 3 is provided on the inner surface of the cylinder member 32.
3 is slidably fitted to the front half 33b of the main body 31a, and the lid member 31 is fixed by the return spring 35 interposed between the front half 33b and the inner end surface of the main body 31a.
It is pressed toward b. The piston rod 33a, which is integrally formed coaxially with the operating piston 33 and extends in the opposite direction to the lid member 31b, is led out to the outside through a hole 31c formed at the end of the main body 31a, and the end portion 21b of the tie rod 21 is removed. I am configuring. The tip of the central portion 21a of the tie rod 21 is coaxially screwed into the lid member 31b and fixed by a lock nut 21c.

The first half 33 fitted to the cylinder member 32
A cylindrical unlocking piston 34 having an outer diameter substantially the same as that of the front half 33b is fitted to the outer periphery of the second half of the actuating piston 33 formed to have a diameter slightly smaller than that of the front half 33b.
A slight distance can be slid between the forward position where it comes into contact with the end face of b and the retracted position where it comes into contact with the retaining ring 34a locked to the actuating piston 33. An oil seal 36a seals between the outer peripheral surface of the lock releasing piston 34 and the main body 31a, and an oil seal 36b seals between the inner peripheral surface of the lock releasing piston 34 and the operating piston 33. A working fluid is supplied to a working chamber formed between the working piston 33, the unlocking piston 34 and the lid member 31b through a port 39 provided with a pipe joint socket.

On the end surface of the front half portion 33b of the actuating piston 33 which comes into contact with the unlocking piston 34, a plurality of guide holes 37 extending in a slightly inclined manner so as to approach the axis of the piston rod 33a are formed along the circumferential direction. Has been formed. The lock ball 38 provided in each of the guide holes 37 is biased obliquely outward toward the lock release piston 34 by the pressing spring 38a. This locking ball 38
When the external force is not applied, the pressing spring 38a makes contact with the unlocking piston 34 and retracts it.
The operating piston 3 is elastically pushed into the wedge-shaped space between the inner surface of the guide hole 37 and the inner peripheral surface of the cylinder member 32.
3 constitutes a one-way clutch that blocks the outward movement of the spring 3 against the return spring 35 in the axial direction.

The above-described cylinder unit 30 for additional cutting is
When the pressure working fluid is not supplied to the port 39, the working piston 33 is moved by the return spring 35.
It is abutted against 1b and is blocked from moving by the locking ball 38, and is locked in the shortest state. When the pressure working fluid is supplied to the port 39, the unlocking piston 34 is first moved toward the forward position, and the locking balls 38 are retracted against the pressing spring 38a to unlock the one-way clutch. To do. Next, the actuating piston 33 and the piston rod 33a move the return spring 3 by the actuating fluid pressure.
The cylinder unit 30 for additional cutting extends as it moves integrally against 5. This extension is stopped by the front half portion 33b coming into contact with the inner end surface of the cylinder member 32. When the working fluid pressure is removed in the extended state of the high-giving cylinder device 30, the working piston 33 is pushed back by the return spring 35 to the position where it abuts the lid member 31b, and the working fluid is discharged from the port 39. In this state, the unlocking piston 34 is in the retracted position, the locking ball 38 is engaged with the inner peripheral surface of the cylinder member 32 by the pressing spring 38a, and the one-way clutch is activated, but the lid member 31 is activated.
The movement of the actuating piston 33 towards b is not impeded.

As shown in FIG. 1, each knuckle arm 70
A dog 72 is fixed to the. Large steering angle sensor 8 including a proximity switch provided near the inside of each of the left and right front wheels 71
No. 1 generates a detection signal indicating that the knuckle arms 70 are in contact with the steering stopper 73 and immediately before the knuckle arms 70 are stopped, and the dogs 72 approach each other, and the vicinity of the maximum steering position is reached. Based on this detection signal, the control circuit 80 sets the 4-port 3-position switching valve 61 to the inoperative position 61b at the center when no large steering angle sensor 81 produces a detection signal, and to the right large steering angle. When the sensor 81 produces a detection signal, it is switched to one operating position 61a, and when the left large steering angle sensor 81 produces a detection signal, it is switched to the other operating position 61c. The input port of the switching valve 61 is connected to the supply pump 60 via the throttle valve 62, the discharge port is connected to the reservoir 67, and the pair of switching ports is connected via the throttle valve 63 and the check valve 64 which are respectively connected in parallel. It is connected to the ports 39 of the left and right increasing cylinder devices 30. The supply pump 60, the switching valve 61, the control circuit 80, the large steering angle sensor 81, and the like constitute a control device A that controls the working fluid supplied to the increasing gear cylinder device 30.

If the steering wheel 10 is rotated rightward,
The tie rod 21 provided with the cylinder mechanism 30 for increasing the speed moves to the left in FIG. 1 via the transmission mechanism 11, and the left and right front wheels 71 are steered to the right as indicated by the solid arrow. The large steering angle sensor 81 on the right side does not generate a detection signal until the steering wheel 10 is largely turned and reaches the maximum steering position. Therefore, since the control circuit 80 sets the switching valve 61 to the inoperative position 61b, each switching The working fluid from the supply pump 60 is not supplied to the port 39 of the cylinder device 30. In this state, the turning-up cylinder device 30 is locked in the most shortened state as described above to perform steering with the Ackermann characteristic, and the turning angle of the right front wheel 71 is changed according to the increase in the rotation angle of the steering handle 10 as shown in FIG. As shown by the characteristic I, the turning angle of the left front wheel 71 increases more slowly than the characteristic I by the characteristic O. In addition, the reaction force applied to each front wheel 71 from the ground resists the return spring 35 and causes the piston rod 3 to move.
3a does not stretch, and therefore, tire wobble due to such a cause does not occur.

When the steering wheel 10 is largely steered to reach the maximum rightward steering position, the right large steering angle sensor 81 produces a detection signal, which causes the control circuit 80 to switch the switching valve 61 to the operating position 61a. In this state, the pressure working fluid from the supply pump 60 is supplied to the port 39 of the left-side increasing cylinder device 30 via the throttle valve 63 and the check valve 64, and the working piston 33 and the piston rod 33a are returned as described above. It is stretched against the spring 35 to increase the turning angle of the left front wheel 71 via the end portion 21b of the tie rod 21. That is, at the maximum steering position, the front wheel 71 on the left side increases to a maximum steering angle to the right, as shown by the broken line Oa in FIG. 3, until the turning angle increases to become substantially equal to the turning angle of the front wheel 71 on the right side. The speed of increase of the cutting angle is adjusted by the opening degree of the throttle valve 62.

When the steering wheel 10 is returned from the maximum rightward steering position, the large steering angle sensor 81 on the right side does not generate a detection signal. Therefore, the control circuit 80 returns the switching valve 61 to the inoperative position 61b and extends the left side. The port 39 of the cylinder unit 30 for increasing the number of passages is connected to the reservoir 67 via the throttle valve 63. As a result, the cylinder device 3 for additional cutting
Zero returns to the shortest state as described above, and thereafter, the cutting angle of the left and right front wheels 71 decreases due to the Ackermann characteristic. The speed at which the cylinder unit for increasing the speed 30 returns to the shortest state is the throttle valve 6
It is adjusted by the opening degree of 3.

Even when the steering wheel 10 is steered to the left, the left and right front wheels 71 are initially steered by the Ackermann characteristic similarly to the above, and when the maximum steering position is reached, the right front wheel 7 is reached.
The turning angle of 1 increases until it becomes almost equal to that of the left front wheel 71, and when returning, the turning angle decreases with similar characteristics.

According to the first embodiment as described above, the normal Ackerman characteristic is obtained until reaching the vicinity of the maximum steering position, and the sideslip of the tires of the left and right front wheels 71 at the time of turning of the vehicle is reduced, so that the vehicle can turn smoothly. Also, tire wear is reduced. Further, if the maximum turning angle of the front wheel 71 on the inner side in the steering direction is the same as the conventional one, the turning radius of the vehicle at the maximum steering angle is reduced by the increase of the turning angle of the steering wheel 71 on the outer side. At the maximum steering angle, the skid of the left and right front wheels 71 increases, but in that state, the vehicle speed is low and the time is short, so tire wear does not pose a problem. In addition, the housing 31 is integrally connected to the central portion 21a of the tie rod 21 and the piston rod 33a is integrally connected to the end portion 21b of each of the additional cylinder devices 30. Space is reduced, and the risk of interference with other body parts is greatly reduced.

Although in the above description the parallel characteristic is obtained by operating the turning-up cylinder device 30 located outside in the steering direction near the maximum steering position, the turning-up cylinder device 30 located inside in the steering direction or inside and outside. You may make it operate | use both cylinder systems 30 for an increase, and may obtain a parallel characteristic. In this case, when shifting to the parallel characteristic, the steering wheel 10 is rotated by the operation of the cylinder mechanism 30 for additional turning.

In the second embodiment shown in FIG. 4, the orientation of the knuckle arm 70 is different from that of the first embodiment. That is, in the first embodiment, the knuckle arm 70 extends rearward from the kingpin and is connected to the tie rod 21.
In the second embodiment, the knuckle arm 70 extends forward from the kingpin and is connected to the tie rod 21, and accordingly, the specific structure of the cylinder unit 30 for additional cutting is different from that of the first embodiment.

Referring to FIG. 4, the cylinder mechanism 30 for increasing the number of cuts according to the second embodiment has an operating piston 33 slidably fitted in a cylinder member (not shown) in a housing 31. The piston rod 33a, which is coaxially fixed to the actuating piston 33, is led out through the housing 31 in a liquid-tight manner to form an end portion 21b of the tie rod 21. Therefore, unlike the first embodiment, the tie rod 21 normally has the maximum length. Further, unlike the first embodiment, the increasing cylinder device 30 of the second embodiment does not include the locking ball 38 and the unlocking piston 34 for locking the tie rod 21, but even if they are provided, Good. Although illustration is omitted, a steering stopper for restricting the maximum turning angle of the front wheel 71, which is on the inner side in the steering direction, is provided. Other configurations are first
The detailed description is omitted because it is the same as the embodiment.

If the steering wheel 10 is rotated rightward,
The tie rod 21 provided with the cylinder device 30 for increasing the speed is moved rightward, and the left and right front wheels 71 are steered rightward.
Until the large steering angle sensor 81 on the right side reaches the maximum steering position at which a detection signal is generated, the control circuit 80 sets the switching valve 61 to the inoperative position 61b and supplies it to the port 39 of each cylinder for increasing gears 30 from the supply pump 60. Working fluid is not supplied. Therefore, the steering device having the Ackermann characteristic is performed with each of the increasing-cylinder cylinder devices 30 remaining in the most extended state. When the rightward maximum steering position is reached, the right large steering angle sensor 81 generates a detection signal, which causes the control circuit 80 to switch the switching valve 61 to the operating position 61a, whereby the pressure working fluid from the supply pump 60 is left. Is supplied to the port 39 of the increasing cylinder unit 30 for reducing the actuating piston 33 and the piston rod 33a against the return spring 35, thereby increasing the cutting angle of the left front wheel 71. That is, at the maximum steering position, the left front wheel 71 increases its turning angle until it becomes approximately equal to the turning angle of the right front wheel 71 at the maximum steering position, as indicated by the broken line Oa.

When the steering wheel 10 is returned from the rightward maximum steering position, the large steering angle sensor 81 on the right side does not generate a detection signal. Therefore, the control circuit 80 returns the switching valve 61 to the non-operating position 61b to increase the left steering angle. The cylinder device 30 is returned to the most expanded state by the return spring 35, and thereafter, the cutting angle of the left and right front wheels 71 is reduced due to the Ackermann characteristic. Even in the case of leftward steering, as in the above case, if the left and right front wheels 71 are initially steered by the Ackermann characteristic, the left front wheel 71 reaches the maximum steering angle, and the left large steering angle sensor 81 generates a detection signal, The turning angle of the front wheel 71 increases until it becomes almost equal to that of the left front wheel 71. Even when the steering wheel 10 is steered to the left, the left and right front wheels 71 are initially steered by the Ackermann characteristic similarly to the above, and when the maximum steering position is reached, the turning angle of the right front wheel 71 is almost the same as that of the left front wheel 71. It increases until they become equal, and when they are returned, each cutting angle decreases with similar characteristics.

According to the second embodiment as described above, it is possible to obtain substantially the same effect as that of the first embodiment. The second
The characteristics of the return spring 35 of the embodiment are set such that the tie rod 21 does not contract due to the reaction force applied to each front wheel 71 from the ground, and the tie rod 21 contracts smoothly due to the working fluid supplied from the supply pump 60. deep.

The third embodiment shown in FIG. 5 is an application of the present invention to a rack and pinion type front wheel steering system. The rack bar 22 is laterally slidably supported on the vehicle body B by a member (not shown), and its left and right ends support the left and right front wheels 71 via a pair of link rods 23 having ball joints at both ends. It is connected to the arm 70. In the third embodiment, the rack bar 22 and the link rod 23 constitute the steering link device 20 that connects the left and right knuckle arms 70. The rack bar 22 is moved by the steering handle 10 via the transmission mechanism 11 including the handle shaft 12 and the rack and pinion mechanism 16, and steers the left and right front wheels 71. Rack bar 22
In the left and right working chambers of the power cylinder 24 provided in the middle of the engine 6 through the servo valve 25 that is provided in the middle of the handle shaft 12 and operates according to the handle torque.
The working fluid from the supply pump 60 driven by 6 is supplied and discharged to give the rack bar 22 an increased steering force.

A link rod 23, which is a part of the steering link device 20, is a base end portion 23a connected to the rack bar 22.
And a tip portion 23b connected to the knuckle arm 70, and between these two portions, the same cylinder unit 30 for increasing cutting as in the first embodiment is provided. In the third embodiment, the switching valve 61 for controlling the supply / discharge of the working fluid from the supply pump 60 to / from each of the increasing / reducing cylinder devices 30 is mechanically operated by a cam 85 fixed to the rack bar 22, a cam follower 86 and a control cable 87. Is activated. That is, the cam 85 has three stages of cam surfaces 85a, 85b, 85c, and the cam follower 8 is provided except near the maximum steering position.
6, the switching valve 61 is in the non-actuated position 61b by abutting on the central second cam surface 85b, but the cam follower 86 abuts on the first cam surface 85a when the rightward maximum steering position is reached. The switching valve 61 to the operating position 61a, and when the leftward maximum steering position is reached, the cam follower 86 contacts the third cam surface 85c and the switching valve 61
Is switched to the operating position 61c. In this embodiment, the supply pump 60, the switching valve 61, the cam 8
5, the cam follower 86, the control cable 87, and the like constitute a control device A that controls the working fluid supplied to the high-giving cylinder device 30.

When the steering handle 10 is rotated rightward as shown by the solid line arrow in FIG. 5, the rack bar 22 is moved leftward in FIG. The left and right front wheels 71 are steered to the right via the rod 23 as indicated by the solid arrow. The steering wheel 10 is turned largely and the cam follower 8 is turned.
Until the switch 6 moves to the first cam surface 85a of the cam 85, the switching valve 61 is in the inoperative position 61b, so that the double-grating cylinder device 30 is locked in the shortest state and steering with the Ackermann characteristic is performed. The turning angles of the left and right front wheels 71 increase as the rotation angle of 10 increases as shown by the characteristics I and O in FIG. 3, and tire stagger is not caused by the reaction force applied to the front wheels 71 from the ground. Absent.

When the steering wheel 10 is steered to move the cam follower 86 to the first cam surface 85a of the cam 85, the switching valve 61 is switched to the operating position 61a. As a result, the working fluid from the supply pump 60 is supplied to the left-side increasing cylinder device 30 for expansion, which extends and increases the cutting angle of the left front wheel 71. That is, the left front wheel 71
In the vicinity of the maximum steering position, as shown by the broken line Ob in FIG. 3, the turning angle increases until it becomes approximately equal to the turning angle of the right front wheel 71.

When the steering handle 10 is returned from the rightward maximum steering position, the turning angles of the left and right front wheels 71 decrease in the opposite manner to the above. Even when the steering wheel 10 is steered to the left, the turning angles of the left and right front wheels 71 increase and decrease as described above.

Although not shown in the drawings, throttle valves 62 and 63 and a check valve 64 similar to those in the first embodiment are provided in the pipeline for supplying the working fluid from the supply pump 60 to the cylinder unit 30 for high-grating. ing. The other structure is the same as that of the first embodiment.

The fourth embodiment shown in FIG. 6 is an application of the present invention to a symmetrical link type front wheel steering system used in an independent suspension system. The relay rod 26, whose both ends are jointly supported by a pair of idler arms 28, is connected to the left and right knuckle arms 70 through a pair of tie rods 27 whose left and right symmetrical positions have ball joints at both ends. In the fourth embodiment, this relay rod 2
6, the tie rod 27 and the idler arm 28 constitute a steering link device 20 that connects the left and right knuckle arms 70. The relay rod 26 is moved by the steering wheel 10 via the transmission mechanism 11 similar to that of the first embodiment,
The left and right front wheels 71 are steered with Ackerman characteristics via the tie rods 27.

The relay rod 26 is divided into a central portion 26a connected to the transmission mechanism 11 and an end portion 26b connected to the knuckle arm 70 via a tie rod 27, and between the two portions, the first embodiment and the first embodiment, respectively. The same cylinder unit 30 for increasing the cut is provided. The other structure is the same as that of the first embodiment, and the action and effect are also substantially the same. Therefore, the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

Next, referring to FIG. 7, the cylinder unit 3 for additional cutting is provided.
A modified example of 0 will be described. Housing 41 of this modification
Is composed of a main body 41a and a lid member 41b screwed and fixed to one end of the main body 41a, and a cylinder portion 42 is formed in the intermediate portion of the inner peripheral surface of the main body 41a. An operating piston 43 is slidably fitted to the inner surface of the cylinder portion 42, and
Is pressed toward the lid member 41b by a return spring 45 which is interposed between the spring receiver 43b and the spring receiver 43b which is in contact with the inner end surface thereof. An oil seal 46a seals between the outer peripheral surface of the operating piston 43 and the main body 41a. The piston rod 43a, which is integrally formed with the working piston 43 coaxially, is led out to the outside through a hole at the end of the main body 41a,
The end portion 21b of the tie rod 21 (or the link rod 2
3 or the end portion 26b of the relay rod 26). The lid member 41b includes a central portion 21a of the tie rod 21 (or a proximal end portion 23a of the link rod 23, or a central portion 26 of the relay rod 26).
a) is screwed coaxially and is fixed by a lock nut 21c.

A lock piston 44 is slidably fitted in the main body 41a at right angles to the axis of the actuating piston 43, and two oil seals 46b are provided between the main body 41a and the lock piston 44.
It is sealed by 46c. Locking piston 44
Is urged toward the axis of the operating piston 43 by a pressing spring 47 interposed between the stopper member 41c provided on the main body 41a, and the projection 44a at the tip is for operating when no external force is applied. The piston 43 for engagement is engaged with the rear end surface of the piston 43 to prevent the piston 43 for operation from retracting, and the cylinder unit 30 for increasing gear is locked in the shortest state.

When the pressure working fluid pressure is supplied to the port 39, the locking piston 44 first moves backward against the pressing spring 47 to release the backward locking of the working piston 43, and then the oil passage 48 is opened. Actuating piston 43 and lid member 41
Supply pressure working fluid to the working chamber between b. As a result, the operating piston 43 resists the return spring 45, and
3b is moved to the position where it abuts, and the cylinder unit for additional cutting 30 extends. When the working fluid pressure is removed in this extended state, the working piston 43 is pushed back by the return spring 45 to the position where it abuts the lid member 41b, and then the locking piston 44 is moved forward by the pressing spring 47 to advance the cylinder for doubling. The device 30 is locked. The additional cutting cylinder device 30 of this modification can be used as it is in each of the above-described embodiments.

Next, a fifth embodiment in which the present invention is applied to a rack and pinion type front wheel steering system will be described with reference to FIGS. In this embodiment, a steering link device 20 is composed of a rack bar 22 and left and right link rods 23, and a cylinder unit 30 for increasing the number of cuts is provided at a connecting portion between the rack bar 22 and each link rod 23. The rack bar 22 is moved by the steering handle 10 via the transmission mechanism 11 having the same configuration as in the third embodiment to steer the left and right front wheels 71.

Next, the details of the cylinder unit 30 for additional cutting used in the fifth embodiment will be described with reference to FIG. The housing 51 of the additional cutting cylinder device 30 includes a large-diameter cylindrical main body 5
1a and a lid member 51b screwed and fixed to one end thereof, and a cylinder member 52 is provided at an intermediate portion of an inner peripheral surface of the main body 51a.
Are fitted and fixed. The front half portion 53b of the operating piston 53 is slidably fitted to the inner surface of the cylinder member 52, and the return spring 55 is interposed between the front half portion 53b and the inner end surface of the main body 51a.
It is pressed toward the lid member 51b by a and 55b. A boss portion protruding outward is formed at the center of the lid member 51b, and a screw portion 51c formed at the center thereof is used to
The housing 51 is coaxially screwed and fixed to both ends of the rack bar 22. The socket 59a of the ball joint 59 is coaxially screwed and fixed in the boss portion 53a formed at the center of the operating piston 53.
The joint ball 59b held inside is integrally formed with one end of the link rod 23 whose other end is connected to the knuckle arm 70. Conical openings 51e and 53c are formed on the front side of the central portion of the main body 51a and the actuating piston 53 to allow the link rod 23 to swing.

The first half 53 fitted to the cylinder member 52
A cylindrical unlocking piston 54 having an outer diameter substantially the same as that of the front half portion 53b is fitted on the outer periphery of the rear half of the operating piston 53 formed to have a diameter slightly smaller than that of the front half portion 5b.
It is possible to slide a little distance between the forward position where it comes into contact with the end face of 3b and the retracted position where it comes into contact with the retaining ring 54a locked to the actuating piston 53. An oil seal 56a seals the outer peripheral surface of the lock releasing piston 54 and the lid member 51b, and an O ring 56b seals the inner peripheral surface of the lock releasing piston 54 and the operating piston 53. The outer peripheral surface of the boss portion 53a and the main body 51a are fluid-tightly fitted to each other via an oil seal 56c.

In the working chamber formed between the working piston 53, the unlocking piston 54 and the lid member 51b,
The pressure working fluid is supplied through the oil passage 22c formed in the rack bar 22, the port 39 formed in the center of the screw portion 51c, and the pressure guiding groove 51f. Further, a working fluid is supplied to a return working chamber formed between the working piston 53 and the main body 51a via a port 39a formed in the main body 51a. As in the case of the cylinder increasing mechanism 30 of the first embodiment, a plurality of guide holes 57, which are slightly inclined with respect to the central axis, are formed along the circumferential direction on the end face of the actuating piston 53 that comes into contact with the unlocking piston 54. The locking ball 58 formed therein is biased toward the unlocking piston 54 side by the pressing spring 58a.

As in the case of the first embodiment, the increasing cylinder device 30 of the fifth embodiment has a working piston 55 when the pressure working fluid is not supplied to the port 59.
Is in contact with the lid member 51b and is locked in the shortest state. When the pressure working fluid is supplied to the port 59, the lock by the one-way clutch is first released, and then the pressure actuating fluid causes the cylinder unit 30 for expansion to extend. When the working fluid pressure is removed in the extended state of the high-giving cylinder device 30 and the pressure working fluid pressure is supplied to the port 39a, the working piston 53 causes the return spring 55 and the port 39.
The pressure working fluid from a is pushed back to the position where it abuts the lid member 51b, and the working fluid is discharged from the port 39.

As shown in FIG. 8, the working chamber on the right side of the power cylinder 24 is communicated with the port 39 of the cylinder unit 30 for increasing the left side via the relief valve 89 and the check valve 68, and also for increasing the right side. It communicates with the port 39 a of the cylinder device 30. On the other hand, the working chamber on the left side of the power cylinder 24 communicates with the port 39 of the right-side increasing cylinder device 30 via the relief valve 89 and the check valve 68, and also communicates with the port 39a of the left-side increasing cylinder device 30. Has been done. In the fifth embodiment, the supply pump 60, the servo valve 25, the relief valve 89, the check valve 68, and the like constitute the control device A that controls the working fluid supplied to the high-turning cylinder device 30. In this embodiment, the pressure generated by the gear of the power steering device is directly used.
The set pressure of each relief valve 89 is set to a value slightly lower than the relief pressure of the supply pump 60. As shown in FIG. 9, when the pressure working fluid is supplied to the port 39 of each of the multiplying cylinder devices 30 via the oil passage 22c formed in the rack bar 22, each relief valve 89 and the check valve 68 are the power cylinders. It should be built in the 24 pistons.

When the steering handle 10 is rotated rightward as shown by the solid line arrow in FIG.
The rack bar 22 provided with is moved to the left in FIG. 8 via the transmission mechanism 11, and the left and right front wheels 71 are steered to the right via the link rod 23 as shown by the solid line arrow.
The gear generation pressure applied to the right operation chamber of the power cylinder 24 increases as the rotation angle of the steering wheel 10 increases. Until the gear generated pressure of the power steering device reaches the set pressure of the relief valve 89 by turning the steering wheel 10 greatly, the port 39a of the right-side increasing cylinder device 30 is opened.
However, the gear generation pressure is not applied to the port 39 of the left side increasing cylinder device 30. Accordingly, the double-turning cylinder device 30 is locked in the shortest state, and steering with Ackermann characteristics is performed.
The turning angles of the left and right front wheels 71 increase as the rotation angle of 0 increases, as shown by the characteristics I and O in FIG. 3, and the tire does not fluctuate due to the reaction force applied to the front wheels 71 from the ground. .

When the steering wheel 10 is steered greatly to increase the gear generation pressure in the working chamber on the right side of the power cylinder 24 and exceed the set pressure of the relief valve 89, this gear generation pressure is applied to the left side increasing cylinder device 30. The working fluid is supplied by being applied to the port 39, and the working piston 53 is moved against the return spring 55, and the cutting angle of the left front wheel 71 is increased via the link rod 23. This break angle gradually increases until the gear generation pressure reaches the relief pressure of the supply pump 60. That is, the left front wheel 71 increases its turning angle in the vicinity of the maximum steering position until it becomes substantially equal to the turning angle of the right front wheel 71, as indicated by the broken line Ob in FIG. During this time, the port 39a of the left-side increasing cylinder device 30 is in communication with the reservoir 67 via the left-side working chamber of the power cylinder 24.

When the steering handle 10 is returned from the maximum rightward steering position, the pressure generated in the gear in the working chamber on the right side of the power cylinder 24 is gradually reduced, and when the pressure becomes equal to or lower than the set pressure of the relief valve 89, the left increasing cylinder is selected. In the device 30, the working fluid inside is discharged from the port 39 through the check valve 68 and returns to the shortest state, and thereafter, the cutting angle of the left and right front wheels 71 is reduced due to the Ackermann characteristic.

Even when the steering wheel 10 is steered to the left, the left and right front wheels 71 are initially steered by the Ackermann characteristic similarly to the above, and when reaching the maximum steering position, the turning angle of the right front wheel 71 is left. It increases until it becomes almost equal to that of, and when returning, each cutting angle decreases with the same characteristics.

As described above, in the fifth embodiment as well as in the above-mentioned respective embodiments, the normal Ackerman characteristic is obtained until the vicinity of the maximum steering position, and the left and right front wheels 71 when turning the vehicle.
The sideslip of the tire is reduced and you can turn smoothly,
Tire wear is also reduced. Also, the front wheels 7 on the inner side in the steering direction
If the maximum turning angle of 1 is the same as the conventional one, the turning radius of the vehicle at the maximum steering angle becomes smaller by the increase of the turning angle of the outer steering wheel 71. In addition, since the housing 51 of each of the additional cylinder devices 30 has a cylindrical shape fixed to both ends of the rack bar 22, the space required for the operation is small, and there is a great risk of interference with other vehicle body parts. Decrease to.

The sixth embodiment shown in FIG. 10 is a transmission mechanism 11
Includes a handle shaft 12, a rack and pinion mechanism 16, a rack shaft 17, a lever 18, and pins 18a and 18b,
Further, it is the same as the fifth embodiment except that the increasing cylinder device 30 does not include a returning working chamber to which working fluid is supplied through the port 39a. Since the operation and effect are substantially the same as those of the fifth embodiment, the same parts are designated by the same reference numerals and detailed description thereof will be omitted.

In each of the embodiments described above, the parallel cylinder characteristics are obtained by operating the increasing gear cylinder device 30 located outside in the steering direction in the vicinity of the maximum steering position. The device 30 or both the internal and external cylinders 30 for increasing may be operated to obtain parallel characteristics. In this case, when shifting to the parallel characteristic, the steering wheel 10 is rotated by the operation of the cylinder mechanism 30 for additional turning.

Also, in the third to sixth embodiments in which the knuckle arm 71 is oriented in the same direction as in the first embodiment,
The direction of the knuckle arm 71 may be the same as that of the second embodiment, and the doubling cylinder device 30 normally biased to the maximum length by the return spring 35 may be used. Also, in these embodiments, like the second embodiment, the locking ball 38 for locking the tie rod 21, the unlocking piston 34, and the like can be omitted.

[Brief description of drawings]

FIG. 1 is an overall explanatory view of a first embodiment of a steering device according to the present invention.

FIG. 2 is a vertical cross-sectional view of a cylinder unit for additional cutting used in the first embodiment.

FIG. 3 is a characteristic diagram of the turning angles of the left and right front wheels of the steering device according to the present invention.

FIG. 4 is an overall explanatory diagram of a second embodiment.

FIG. 5 is an overall explanatory view of a third embodiment.

FIG. 6 is an overall explanatory diagram of a fourth embodiment.

FIG. 7 is a vertical cross-sectional view of a modified example of the additional cutting cylinder device.

FIG. 8 is an overall explanatory view of the fifth embodiment.

FIG. 9 is a vertical sectional view of a cylinder unit for additional cutting used in a fifth embodiment.

FIG. 10 is an overall explanatory diagram of a sixth embodiment.

[Explanation of symbols]

Reference numeral 10 ... Steering handle, 11 ... Transmission mechanism, 20 ... Steering link device, 30 ... Cylinder device for increasing gear, 31, 41, 51
... Housing, 32, 42, 52 ... Cylinder (cylinder member, cylinder part), 33, 43, 53 ... Operating piston,
35, 45, 55 ... Return springs 35, 70 ... Knuckle arm, 71 ... Steering wheel (front wheel), A ... Control device.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akira Onishi 1-1 Asahi-cho, Kariya city, Aichi Toyota Koki Co., Ltd. (72) Inventor Junichi Miyagi 1-cho, Toyota city, Aichi Toyota Motor Co. (72) Inventor Takahiko Naito 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd.

Claims (1)

[Claims] 1. A steering system in which each knuckle arm supporting left and right steering wheels is connected so that a turning angle of the steering wheel which is inside in a steering direction is larger than a cutting angle of the steering wheel which is outside. A steering device comprising a link device and a transmission mechanism for transmitting the rotation of a steering wheel to a part of the steering link device, comprising: a housing having a cylinder; an operating piston fitted into the cylinder; A return spring that biases the piston toward one end of the housing, one of the housing and one of the operating pistons being on the part side of the steering link device, and the other being on the knuckle arm side. At least the outside of the steering direction is detected by detecting the approach to the maximum steering position and a pair of the cylinders for increasing gears that are connected and provided in the middle of the steering link device. Steering apparatus characterized by a housing and the actuation piston of the increase cutting cylinder unit comprising a has a control device for supplying hydraulic fluid in a direction to relatively move against the return spring.