JPH0714119Y2 - Rear wheel steering system for front and rear wheel steering vehicles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rear wheel steering system for a front and rear wheel steering vehicle capable of steering the rear wheels in conjunction with the steering operation of the front wheels.

2. Description of the Related Art A front and rear wheel steering vehicle that can steer not only front wheels but also rear wheels has been conventionally known, and various types of rear wheel steering devices have been proposed. However, the conventional device of this type has a problem that the structure is complicated and the cost is increased.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks and provide a rear wheel steering device for a front and rear wheel steering vehicle in which there is no delay in the rear wheel steering with respect to the front wheel steering, and the steering angle amount of the rear wheels can be controlled steplessly. Especially.

In order to achieve the above-mentioned object, the present invention extends the vehicle in the front-rear direction and rotates the rotation shaft according to the steering state of the front wheel steering device, and steers the rear wheels by operating in the left-right direction of the vehicle. Rotating rod connected to the rear end of the rotary shaft so as to rotate integrally with the rotary shaft, and the base end side at a position distant from the rotary axis of the rotary shaft. A first control rod, a second control rod having a base end side pivotally attached to the actuation rod, and a front end side pivotally attached to a tip end side of the first control rod; An actuator that rotates about the end sides to displace the positions of the tip-side pivotally attached portions of both control rods, and the tip-end-side pivotally attached portion of the first control rod pivotally attached to the second control rod is Can rotate by drawing an arc passing through the axis of rotation of the rotating body In this way, a rear wheel steering device for a front and rear wheel steering vehicle in which the base end side of the first control rod is pivotally attached to the rotating body is proposed.

Further, in order to achieve the above object, the present invention provides a rotating shaft that extends in the front-rear direction of a vehicle and that rotates according to a steering state of a front wheel steering device, and that rotates integrally with the rotating shaft. , A rotating body connected to the rear end of the rotating shaft, an operating rod that steers the rear wheels by operating in the left-right direction of the vehicle, and an operating rod that integrally operates with the operating rod in the left-right direction of the vehicle. A guide member that is connected to the actuation rod, is orthogonal to the axis of the actuation rod, and extends linearly in the vertical direction, and has a guide hole that passes through the rotation axis of the rotating body; An actuator supported by the rotating body so as to be movable along the guide hole so as to pass through a guide hole portion that intersects the rotation axis of the rotating body, and the actuator is displaced along the guide hole. Actuator Comprises a preparative proposes a rear wheel steering apparatus of the front and rear wheel steering vehicle comprising.

Effect According to the rear wheel steering system having the above-described first configuration, the actuator displaces the positions of the tip-side pivotally-attached portions of the first and second control rods, whereby the steering direction of the rear wheels and the steering direction of the rear wheels by the steering operation of the front wheels are changed. The steering angle amount can be controlled steplessly.

According to the rear wheel steering system of the second configuration, the steering direction of the rear wheels and the steering angle amount thereof can be continuously controlled by moving the actuator in the guide hole by the actuator.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory plan view of a front and rear wheel steering vehicle in which only a portion necessary for understanding the present invention is taken out and shown.

In the vehicle shown here, the left and right front wheels 1, 1 are steered by a steering device 2 on the front wheel side. That is, the rotation of the steering wheel 3 causes the shaft 4 to move.
Rotates, and the rack bar 6 meshed with the pinion 5 at its tip operates in the left-right direction of the vehicle. Along with this, the tie rods 7 and 7 connected to the rack bar 6 operate in the same direction, but these tie rods move through the knuckle arms 9 and 9 that rotate around the axes 8 and 8, respectively, to the front wheels 1. , 1 is connected to the front wheel by the left-right operation of the tie rod 7.
1,1 are steered as shown by the arrow. The above-mentioned steering device on the front wheel side is the same as the conventionally known steering device.

The rear wheel steering system is configured as follows. That is, a rotating shaft 10 extending in the front-rear direction of the vehicle is provided, and a pinion 11 fixed to the tip of the rotating shaft 10 meshes with the rack bar 6 described above. Therefore, when the rack bar 6 is operated in the left-right direction by operating the steering wheel 3, the rotary shaft 10 also rotates. In this way, the rotating shaft 10 rotates according to the steering state of the steering device 2 on the front wheel side.

The rotating body 12 is fixedly connected to the rear end of the rotating shaft 10 as shown in FIGS. 2 and 3, or is connected via a joint (not shown). It is configured to rotate. In this way, the rotating body 12
Is connected to the rear end of the rotary shaft 10 so as to rotate integrally with the rotary shaft 10.

A through hole 13 penetrating in the front-rear direction of the vehicle is bored in the rotary axis O of the rotary body 12, that is, the rotary body portion away from the axis O passing through the rotation center of the rotary body 12, and the first control rod is provided there.
A support shaft 15 fixed to the base end side 14a of 14 is rotatably inserted. In this way, the first control rod 14 is pivotally mounted on the base end side 14a thereof at a position away from the rotation axis O of the rotating body 12. The rotation axis O of the rotating body 12 coincides with the axis of the rotation shaft 10.

The first control rod 14 extends in a direction substantially orthogonal to the rotating shaft 10, and a tip side 16b of a second control rod 16 is pivotally attached to a tip side 14b thereof via a pin 17. This second control rod 16
The base end side 16a of the operating rod 18 extends in the left-right direction of the vehicle.
It is pivotally attached via pin 19. In the illustrated example, the operating rod 18 is an intermediate rod located in the center of the vehicle in the left-right direction.
118 and tie rods 24, 24 connected to the respective ends thereof via joints 25, 25. The proximal side 16a of the second control rod 16 is pivotally attached to the intermediate rod 118.
Of course, 8 may be configured as a single rod or other form of rod.

As shown in FIG. 1, the tie rods 24, 24 are connected to the rear wheels 22, 22 via knuckle arms 21, 21 which are rotatable about the shafts 20, 20 as is well known in the art. By operating the operating rod 18 in the left-right direction of the vehicle, the rear wheels 2
2,22 are steered as shown by the arrow.

The tip of the above-mentioned support shaft 15 penetrating the hole 13 of the rotary body 12 and protruding from the rotary body 12 is connected to an actuator fixed to the rotary body 12, a servomotor 23 in the illustrated example. The operation of the motor 23 causes the first control rod 14 to move toward the base end side.
By pivoting around 14a, the tip pivot parts of both control rods 14 and 16, that is, the pins 17 are displaced. In this case, the tip-side pivotally-attached portion (pin 17) of the first control rod pivotally attached to the second control rod 16 passes through the rotation axis O of the rotating body 12 to form an arc C (second
The base end side 14a of the first control rod 14 is pivotally attached to the rotating body 12 so as to rotate in the drawing. Even if the rotator 12 rotates as described later and the position of the pivot portion of the first control rod on the side of the base end portion 14a moves, the arc C centered on the pivot portion always follows the rotation axis O of the rotator 12. Pass through (see Figures 4 and 5).

With the above configuration, the rear wheels are steered as follows.

First, the distal end side pivotal joints of both control rods 14 and 16, that is, the pin 17
As shown in FIG. 4 (a), it has been introduced on the rotation axis O of the rotating body 12 (in FIG. 4, both control rods are shown).
14 and 16 are in parallel with each other. In this state, the steering wheel 3 is rotated to operate the rack bar 6, and the front wheels 1, 1 are steered to the left as shown in FIG. 6 (a).
The reference numeral 12 rotates around the rotation axis O in the counterclockwise direction in FIG. 4 (a). Therefore, as shown in FIG. 5A, the base end side 14 of the first control rod 14 pivotally attached to the rotating body 12 is shown.
The a rotates together with the rotating body 12 in the counterclockwise direction. However, since the pin 17, which is the pivotal attachment portion of both control rods 14 and 16 is located on the rotation axis O of the rotating body 12, it does not rotate even if the rotating body 12 rotates, and the stopped state is maintained. To do. That is, as shown in FIG. 5 (a), the base end side 14a of the first control rod 14 rotates about the rotation axis O, but the second control rod 16 does not operate at all. Therefore, the operating rod 18 also does not operate,
As shown in FIG. 6 (a), the rear wheels 22, 22 are not steered. The rear wheels 22 and 22 are not steered even when the steering wheel 3 is rotated in the opposite direction to turn the front wheels 1 and 1 to the right, and when the steering angle amount of the front wheels 1 and 1 is any.

Next, as shown in FIG. 4 (b), the pin 17 is displaced by the operation of the servo motor 23 so as to be out of the rotation axis O of the rotating body 12, and in this state, the steering wheel 3 is rotated to rotate the steering wheel 3 as shown in FIG. When the front wheels 1, 1 are steered to the left as shown in b), the base end side 14a of the first control rod 14 is moved to the first position by the counterclockwise rotation of the rotating body 12, as shown in FIG. 5 (b). 5
It rotates in the same manner as in the case of FIG. At this time, since the pin 17 does not coincide with the rotation axis O, it is pushed by the first control rod 14 to operate from the position shown in FIG. 4 (b) to the position shown in FIG. 5 (b), and the second control rod 16 Moves to the left. As a result, the actuating rod 18 is actuated leftward from the position shown in FIG. 4 (b) by a distance indicated by δ ₁ in FIG. 5 (b), and the rear wheel 2
2, 22 are steered to the left as shown in FIG. 6 (b). That is, the front wheels 1 and 1 and the rear wheels 22 and 22 are steered in the same direction, and the front and rear wheels are brought into the in-phase steering state.

When the front wheels 1, 1 are cut to the right, the rotating body 12 rotates clockwise in FIG. 4 (b), so the operating rod 18 moves to the right and the rear wheels 22, 22 move to FIG. 6 (b). ), And the front wheels 1, 1 and the rear wheels 22, 22 are also steered in the same direction.

As described above, by displacing the pin 17 in the direction shown in FIG. 4 (b), the same phase state of the front and rear wheels can be obtained when the front wheels 1, 1 are steered in either direction. .

Next, as shown in FIG. 4 (c), the pin 17 is displaced in the direction opposite to that of FIG. 4 (b) by the operation of the servo motor 23,
In this state, if the front wheels 1, 1 are steered to the left as shown in FIG. 6 (c), the counterclockwise rotation of the rotating body 12 causes the first control rod to move as shown in FIG. 5 (c). 14 proximal ends
14a also rotates counterclockwise. At this time, the second control rod 1
6 is pushed by the first control rod 14 to operate as shown in FIG. 5 (c), and the operating rod 18 moves to the right. Therefore, as shown in FIG. 6 (c), the rear wheels 22, 22 are steered to the right. That is, the front wheels 1 and 1 and the rear wheels 22 and 22 are steered in opposite directions, so that the front and rear wheels are in the anti-phase steering state.

When the front wheels 1, 1 are turned to the right, the rotating body 12 rotates clockwise and the operating rod 18 moves to the left.In this case as well, the front wheels 1, 1 and the rear wheels 22, 22 are in opposite directions. Steered to.

As described above, the operation of the servo motor 23 brings the positions of the distal end side pivotal portions (pins 17) of the control rods 14 and 16 to the position of the rotation axis O of the rotating body 12, or from this position. By shifting to the other direction, the state without rear wheel steering, the front and rear wheel in-phase state, or the front and rear wheel anti-phase state can be freely obtained, and the amount of shift of the tip is large or small. Thus, it is possible to regulate the magnitude of the steering angle amount of the rear wheels 22, 22 according to the steering angle amount of the front wheels 1, 1. In addition, there is no delay in the response of the rear wheels 22, 22 to the steering of the front wheels 1, 1, and the steering angle amount of the rear wheels 22, 22 can be adjusted steplessly. 4 (a), (b), and (c) show the respective positions of the pin 17 when the front wheels 1, 1 are not steered.
Even if the pin 17 is moved while steering the
Obviously you can steer two.

When the vehicle actually travels, the controller 30 shown in FIG.
The servomotor 23 controls the rotation direction and the rotation amount of the servomotor 23 according to the vehicle speed of the vehicle. That is, in response to a vehicle speed signal input to the controller 30 from a vehicle speed sensor (not shown), the motor 23 rotates a predetermined amount in the direction corresponding to the vehicle speed, and the rear wheel
The steering direction of 22,22 and its steering angle amount are determined. For example, as is known per se, the servo motor 23 drives the vehicle such that the vehicle travels in the front-rear wheel anti-phase state at low-speed traveling and the vehicle travels in the front-rear wheel in-phase state when a certain speed is exceeded.
Is controlled.

The above is the embodiment corresponding to the configuration described in claim 1, and next, the embodiment corresponding to the configuration described in claim 2 will be described.

Also in this embodiment, the configuration of the steering device on the front wheel side and the rotary shaft 10 are the same as those in the previous embodiment, and the description thereof will be omitted. As shown in FIGS. 7 to 9, a rotary body 31 is connected to the rear end of the rotary shaft 10 via a universal joint 32. The rotating body 31 is a rotating shaft.
It is connected to the rear end of the rotating body 10 so as to rotate integrally with the rotating body 10, but the rotating body 31 is formed with a vertically long groove 33, and the upper and lower wall portions thereof are formed. Screw member
34 is rotatably supported. One end of the screw member 34 penetrates the upper wall of the rotating body 31 and is connected to an actuator which is fixed to the upper surface of the upper wall and is composed of, for example, a servomotor 35, and the motor 35 drives the screw member 34 to rotate. Is configured. A nut 36 is screwed into the screw member 34,
The nut 36 is guided along the concave groove 33, but is regulated by the concave groove 33 to prevent its rotation.

A guide roller 37 is rotatably supported by the nut 36, and the roller 37 is fitted in a guide hole 39 of a guide member 38 so as to be rollable without rattling. Left and right tie rods 24, 24 are connected to the guide member 38 via joints 25, 25. From these tie rods 24, 24, each rear wheel 2
The configuration up to 2,22 is the same as in the case of FIG. That is, in this example, the tie rods 24, 24 constitute an operating rod,
By operating this in the left and right direction of the vehicle, the rear wheels 2
2,22 are steered. The guide member 38 is such a tie rod.
The tie rods 24, 24 are connected to the tie rods 24, 24 so as to operate in the left-right direction of the vehicle integrally with the 24, 24.

The guide hole 39 is a long hole which is orthogonal to the axis X of the tie rods 24, extends linearly in the vertical direction, and passes through the rotation axis O of the rotating body 31, that is, the central axis of the rotation shaft 10. Is formed as.

The guide roller 37 fitted in the guide hole 39 is supported by the rotating body 31 via the nut 36 and the screw member 34.
Is a constitutional example of an actuator supported by the rotating body 31 so as to be movable along the guide hole 39 so as to pass through the portion of the guide hole 39 intersecting the rotation axis O of the rotating body 31. There is.

The servo motor 35 rotates the screw member 34 by its rotation, thereby moving the nut 36 up and down along the guide hole 39, and constitutes one structural example of an actuator that displaces the operator along the guide hole. It is a thing.

As shown in Fig. 10 (a), insert the guide roller 37 into the guide hole.
At the center of 39, that is, at the guide hole portion that intersects with the rotation axis O of the rotating body 31 that is also the rotation axis of the rotation shaft 10, in this state, as shown in FIG. When cut into pieces, the rotary body 31 rotates counterclockwise as shown in FIG. 11 (a) as in the previous embodiment. However, guide rollers
37 is located on the rotation axis O of the rotating body 31,
Even if 31 rotates, the rotation is not transmitted to the guide member 38, and the member 38 remains stationary as shown in FIG. 11 (a). Therefore, the tie rods 24, 24 also do not operate, and the rear wheels 22, 22 are not steered as shown in FIG. 12 (a). The same applies when the front wheels 1, 1 are steered to the right.

Next, the screw member 34 is rotated by the operation of the servo motor 35, and the nut 35 is moved upward as shown in FIG. 10 (b).
The guide roller 37 is brought to a position away from the rotation center axis O of the rotating body 31. In this state, when the front wheels 1, 1 are steered to the left as shown in FIG. 12 (b), the rotating body 31 rotates counterclockwise as shown in FIG. 11 (b). Since the rotary body 31 is located away from the rotation axis O, the guide roller 37 also rotates around the rotation axis O in the counterclockwise direction. Therefore, the guide member 38 is
Is pushed to the left by the tie rod 24,2
4 operates to the left as shown in FIG. 11 (b), and the rear wheels 22,
22 is steered to the left as shown in FIG. 12 (b). That is,
A front and rear wheel in-phase steering state can be obtained. When the front wheels are turned to the right, the rotator 31 also rotates clockwise, the tie rods 24 and 24 move to the right, and the rear wheels 22 and 22 are turned to the right. Becomes

Next, the guide roller 37 is moved by the operation of the servo motor 35,
When the front wheels 1, 1 are cut to the left as shown in FIG. 12 (c) by bringing them from the position of FIG. 10 (a) to a lower position as shown in FIG. 10 (c), FIG. 11 (c). As described above, the guide member 38 is pushed to the right by the counterclockwise rotation of the rotating body 31. Therefore, the tie rods 24, 24 also move to the right, and the rear wheels 22, 22 move to the first position.
As shown in Fig. 12 (c), the vehicle is steered to the right. This is the front-rear wheel anti-phase steering state. If you turn the front wheels 1, 1 to the right,
Since the rotating body 31 rotates in the clockwise direction, the guide member 38 and the tie rods 24, 24 move leftward, the rear wheels 22, 22 are steered leftward, and in this case also, the front-rear wheel antiphase steering state is established.

Also in the above-described embodiment, the guide roller 37 is brought to a position that coincides with the rotation axis O of the rotating body 31 by controlling the rotation direction and the rotation amount of the servo motor 35, or one direction from this position, or the other. By shifting to the direction of, it is possible to freely obtain one of the state without rear wheel steering, the front and rear wheel in-phase state, and the front and rear wheel anti-phase state. At that time, the amount of shift d of the guide rollers 37 (FIGS. 10 (b) and 10 (c)) does not depend on the amount of steering angle of the rear wheels 22,22 depending on the amount of steering angle of the front wheels 1,1. It can be regulated in stages. The control mode of the servomotor 35 by the controller 30 (FIG. 1) is the same as that of the previous embodiment.

According to the configuration described above, the rotating body 31 connected to the rotating shaft 10
And the guide member 38 having the guide hole 39 are constituted by separate members, the guide hole 39 is a long hole which is orthogonal to the axis X of the tie rods 24 and 24 and extends linearly in the vertical direction. Formed as a guide member 38
And tie rods 24, 24, without an intermediate member
Even if it is directly connected, a predetermined correct operation can be obtained as described above. For example, as shown in FIG. 10, when the guide roller 37 is brought upward or downward from the center of the guide hole 39 in a state where the front wheel is not cut to the left and right and therefore the rotating body 31 is stopped in the neutral state, Since the guide roller 37 linearly extends in the vertical direction and moves along the guide hole 39 extending in the direction orthogonal to the tie rods 24, 24, the tie rods 24, 24 do not move laterally. Guide member 3
Even if an intermediate member such as a rotating member is not provided between 8 and the tie rods 24, 24, the operation of the tie rods can be reliably prevented when the tie rods 24, 24 should not be operated. In this way, the guide member 38 and the tie rods 24, 2
Since 4 can be connected without an intermediate member, the configuration of the entire device can be simplified, the rear wheels are correct, and there is no delay with respect to steering of the front wheels, without particularly increasing the assembly accuracy of each element of the device. The rear wheels can be steered.

Moreover, since the guide hole 39 extends linearly in the vertical direction,
The guide roller 37 also operates linearly, so that the element for driving the guide roller 37 can be simplified. Like the embodiment shown in FIGS. 7-11,
When the guide roller 37 is actuated by the screw member 34 and the nut 36, a simple linear screw member is used as the screw member 34, and as the nut 36, a nut having a simple form that is screwed to the screw member 34 is used. It suffices to use it, and the configuration can be simplified.

In the embodiment shown in FIGS. 7 to 12, a nut 36 is screwed onto a screw member 34 rotated by a servomotor 35, and a guide roller 37 as an operator is provided on the nut 36 so that the rotation of the motor 35 guides the guide roller 37. Although the roller 37 is configured to be displaced along the guide hole 39, the guide roller 37 can be displaced by other appropriate means, and in that case, the configuration can be simplified. For example, it is also possible to support an actuator composed of a fluid pressure operated cylinder on a rotating body, connect its piston rod to a guide roller, and displace the guide roller by the operation of the cylinder. In this case, the nut 36 and the screw member 34 are It can be omitted. Further, instead of the guide roller 37, a sliding member that slides in the guide hole 39 may constitute the actuator.

Similarly, also in the embodiment shown in FIGS. 1 to 6, the tip end side pivotal attachment portions of the first and second control rods are displaced by an actuator other than the motor 23, which is composed of, for example, a fluid pressure operating cylinder. It is also possible to configure.

Advantageous Effects of Invention According to the configurations of claims 1 and 2, the structure of the rear wheel steering device is simpler than the conventional one, there is no delay of the rear wheel steering with respect to the front wheel steering, and the rear wheel steering angle amount can be controlled steplessly. Can be provided.

In particular, according to the structure of claim 2, the rotating body and the guide member are made of different members, and the guide hole formed in the guide member is orthogonal to the axis of the operating rod and in the vertical direction. Since it extends linearly for a long time, even if the operating rod is directly connected to the guide member without an intermediate member, a predetermined rear wheel steering operation can be obtained, and the operation can be performed accurately and moreover. The rear wheels can be steered without any delay with respect to the front wheel steering. Further, since the actuator moves linearly along the guide hole, the structure for operating the actuator can be simplified, which also reduces the cost of the device.

[Brief description of drawings]

1 is a schematic plan view of a front and rear wheel steering vehicle, FIG. 2 is a rotating body,
FIG. 3 is a diagram showing a related configuration of a control rod and an actuation rod as seen from the rear side of the vehicle, FIG. 3 is an exploded perspective view of FIG. 2, and FIGS. 4 (a), (b) and (c) are both control rods. Explanatory diagram showing a state of displacing the pivot portion of FIG. 5, (a), (b),
(C) is an explanatory view showing the state of each control rod when the rotating body rotates, and FIGS. 6 (a), (b) and (c) are explanatory diagrams showing the steering state of the front wheels and the rear wheels. FIG. 7 is a perspective view showing a main part of a rear wheel steering system in another embodiment, FIG. 8 is a sectional view taken along the line VIII-VIII of FIG. 7, and FIG. 9 is an exploded perspective view thereof.
FIGS. 10 (a), (b), and (c) are explanatory views showing a situation in which the guide roller is displaced, and FIGS. 11 (a), (b), and (c).
[Fig. 12] is an explanatory view showing an operation state of the guide member when the rotating body is rotated, and Figs. 12 (a), (b) and (c) are explanatory views showing steering states of the front wheels and the rear wheels. 1 ... Front wheel, 2 ... Steering device 10 ... Rotary shaft, 12,31 ... Rotating body 14 ... First control rod, 14a ... Base end side 14b ... Tip end, 16 ... Second control rod 16a …… Base end side, 16b …… Tip end side 18 …… Operating rod, 38 …… Guide member, 39 …… Guide hole C …… Arc, O …… Rotation axis, X …… Axis

Claims (2)

[Scope of utility model registration request] 1. A rotary shaft that extends in the front-rear direction of a vehicle and that rotates in accordance with a steering state of a front-wheel steering device; and an operating rod that steers the rear wheels by operating in the left-right direction of the vehicle; A rotating body connected to a rear end of the rotating shaft so as to rotate integrally with the rotating shaft, and a first control rod pivotally mounted at a base end side at a position apart from a rotating axis of the rotating body. A second control rod pivotally attached to the actuating rod at its base end side and pivotally attached to its tip end side to the tip end side of the first control rod; and the first control rod about its base end side. And an actuator for displacing the positions of the tip end side pivotal attachment portions of both control rods, wherein the tip end side pivotal attachment portion of the first control rod pivotally attached to the second control rod moves the rotation axis of the rotating body. The first control rod of the first control rod Rear wheel steering apparatus of the front and rear wheel steering vehicle that pivotally connected to the end side rotating member. 2. A rotary shaft extending in the front-rear direction of the vehicle and rotating in accordance with a steering state of a front wheel steering device, and a rear end of the rotary shaft so as to rotate integrally with the rotary shaft. And a rotating body connected to the steering section, an operating rod that steers the rear wheels by operating in the left-right direction of the vehicle, and an operating rod that is integrally connected to the operating rod and operates in the left-right direction of the vehicle. And a guide member that is orthogonal to the axis of the operating rod and extends linearly in the vertical direction and has a guide hole that passes through the rotation axis of the rotating body, and the rotation axis of the rotating body. An actuator that is supported by the rotating body so as to be movable along the guide hole so as to pass through the intersecting guide hole portion, and an actuator that displaces the operator along the guide hole. Front and rear wheel Car rear-wheel steering system.