JPH0735814Y2 - Rear wheel steering system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rear wheel steering system for an automobile.

2. Description of the Related Art Various automobiles have been developed in the past, in which the front wheels are steered by the steering operation of the steering wheel and the rear wheels are simultaneously steered.
-It has already been published in the Gazette No. 66581.

Problems to be Solved by the Invention As described above, a rear wheel steering system of an automobile, in which the rear wheels are steered at the same time as the front wheels are steered, is generally a rack and pinion type gear meshing similar to the front wheel steering system. Using the mechanism,
In many cases, the gear meshing mechanism is interlocked with the steering operation of the front wheel steering device to rotate the rear wheels around the kingpin.

However, such a conventional rear wheel steering system has a problem that the structure is extremely complicated and expensive, and in addition, a considerably large space is required.

Further, since the steering angle of the rear wheels is extremely small compared to the steering angle of the front wheels, if the rear wheel steering is attempted by the gear meshing mechanism or the link mechanism as described above, the backlash of the gear meshing portion or the link mechanism will be lost. Since the play etc. has a great influence on the rear wheel rudder angle control, it is necessary to remarkably improve the accuracy of the gears and links to minimize the backlash and play.
There is also a problem that productivity will drop significantly.

Further, if it is attempted to directly steer the rear wheels by an actuator such as a hydraulic device or an electric motor, it is difficult to accurately control the fine steering angle of the rear wheels by the actuator itself, and the rear wheels by the actuator itself are difficult to control. There is a problem that it is very difficult to maintain the steering angle.

An object of the present invention is to provide a rear wheel steering device that can solve all the above-mentioned conventional problems.

Means for Solving the Problems The present invention has two suspension links, the front and rear suspension wheels, in which the base ends of front and rear suspension links are rotatably mounted on a vehicle body member. In a double-link rear suspension that is supported so that it can swing up and down, a shaft that supports the base end of one of the front and rear suspension links on the vehicle body-side member It is rotatably attached to a member and is composed of a support shaft whose other end is an eccentric shaft, and the base end of the one suspension link is rotatably fitted to the eccentric shaft via a sliding bush. An eccentric shaft portion of the left and right support shafts is linked by a link member, and an actuator for rotating the left and right support shafts which is activated by steering the front wheels is provided. Further, the left and right support shafts are rotated, and only one of the front and rear suspension links is displaced in the left and right directions so that the rear wheels are steered.

Action As described above, the support shaft of one of the front side and the rear side of the suspension link to the member on the vehicle body side is formed of an eccentric shaft, and only one of the suspension links moves in the left-right direction by the operation of the actuator. Since the rear wheels are steered by being displaced, the rotation angle of the actuator can be made large with respect to the steering angle of the rear wheels with a very simple structure. Can be accurately controlled.

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

In FIGS. 1 and 2, reference numeral 1 denotes a suspension cross member for mounting and supporting a rear suspension link, which will be described later, and a rear wheel steering device case 2 is mounted on a rear surface portion of the suspension cross member 1 with bolts and nuts.

Suspension link support shafts 3 and 4, which will be described later, are rotatably supported at both left and right ends of the rear wheel steering device case 2, and an electric motor is provided in the rear wheel steering device case 2 near one of the support shafts 4. 5 is attached to the electric motor 5
The rotation of one of the support shafts 4 rotates through a reduction gear mechanism (not shown) including a worm gear and a worm wheel, and the rotation of the one support shaft 4 causes the one lever 6 and the connecting rod 7 to rotate.
And the other support shaft 3 is transmitted via a link member composed of the other lever 8 so that both support shafts 3 and 4 rotate together.

The front end portions of the support shafts 3 and 4 are eccentric shaft portions 3a and 4a, and the eccentric shaft portions 3a and 4a are used when the rear wheel steering device case 2 is attached to the suspension cross member 1. The member 1 penetrates the rear wall of the member 1 and protrudes inward, and the eccentric shaft portions 3a, 4a are fitted to the left and right rear suspension links 10, 10 such that the end portions of the vehicle body center side thereof are rotatable.

On the front surface of the suspension cross member 1, the left and right front suspension links 9, 9 are attached at the vehicle body center side end portions so as to be rotatable by a front support shaft 11.

The ends of the front and rear suspension links 9 and 10 on the side of the vehicle body are pivotally attached to the front and rear sides of a rear wheel support member that rotatably supports the rear wheel shaft. And rear suspension links 9,10
Bushings made of an elastic material such as rubber are interposed at the rotating portions at both ends of the.

The rear portion of the rear differential device 12 is supported at the center of the suspension cross member 1, and the left and right drive shafts 13 for transmitting driving force from the rear differential device 12 to the left and right rear wheels pass through the suspension cross member 1. ing.

Undersides of the left and right support shafts 3 and 4 and the like are front and rear end portions fixed to the front wall portion of the suspension cross member 1 and rear end portions fixed to the lower surface portion of the rear wheel steering device case 2. It is a guard, and the underguards 14 and 14 have a structure in which the lower side of the main portion of the rear wheel steering mechanism such as the support shafts 3 and 4, the levers 6 and 8 and the connecting portion between these and the connecting rod 7 is closed and guarded. .

In the above description, the eccentric shaft portion is generated when a control unit (not shown) outputs an output for rotating the electric motor 5 in the normal direction or the reverse direction in accordance with the front wheel steering, and the electric motor 5 rotates in a certain direction and one rear side support shaft 4 rotates. 4a rotates and displaces to the right or left side, the lever 6 also rotates integrally with it, the other lever 8 also rotates via the connecting rod 7, and the other rear support shaft 3 moves in the opposite direction. When rotated, the eccentric shaft portion 3a is displaced rightward or leftward in the same direction as 4a.

Then, as shown in FIG. 3, since the rear wheel W is supported by the front suspension link 9 and the rear suspension link 10 so as to be vertically swingable, the rear suspension link 10
Since the center of swinging, that is, the center of the eccentric shaft portions 3a and 4a is displaced to the right or left as described above, and the swinging center of the front suspension link 9 is not displaced, the left and right rear wheels are steered to the left or right. It

In the rear wheel steering mechanism as described above, the steering angle θ of the rear wheels is as shown in FIG. 3 the distance L between the front link 9 and the rear link 10 between the mounting portions of the rear wheel W and the rear link 10. Is determined by the amount of lateral displacement d of, and is represented by θ = d / L, for example d = 6m
When m, L = 180 mm, θ≈2 °, and d can be arbitrarily controlled between 0 and 6 mm by the rotation angles of the support shafts 3 and 4, so that the turning angle θ of the rear wheel W can be controlled by turning the electric motor 5. Almost 2 depending on the angle of movement
It can be controlled arbitrarily within the range below.

In the above, if each eccentric amount of the eccentric shaft portions 3a, 4a is made to coincide with the one-sided displacement amount d of the rear link 10 required to obtain the maximum steering angle θ _M from the neutral position of the rear wheels, 3,4 ± 9
The rear wheel W is steered within the turning angle range of 0 °, that is, the turning angle range of 180 °, and the turning angle of the electric motor 5 with respect to the turning angle of the rear wheel W becomes large, so that the rear wheel W moves. It is possible to accurately control the minute angle steering.

The specific structure of the shaft attachment portion of the rear link 10 to the rear wheel steering device case 2 of the base end portion is as shown in FIGS. That is, the tip ends of the support shafts 3 and 4, which are fitted and supported by the rear wheel steering device case 2 so that the base ends thereof are rotatable via bearings, are attached to the center lines XX of the support shafts 3 and 4. Eccentric shaft portions 3a, 4a formed to be eccentric by d are provided.
A cylindrical sliding bush 15 is fitted on the outer peripheral surface of 4a, and the inner cylinder 15a and the elastic ring 1 are attached to the outer circumference of the sliding bush 15.
The rear end of the rear suspension link 10 is assembled through a normal bush composed of 5b and the levers 8 and 6 are screwed to the tip ends of the eccentric shafts 3a and 4a, respectively. .

As the actuator, other than the combination of the electric motor and the speed reducer, any device such as a hydraulic device or a vacuum actuator can be used.

In the embodiment shown in FIGS. 1, 2 and 4 and 5, the left and right rear support shafts 3,
4 shows an example in which the eccentric shaft portions 3a and 4a are linked by a link member composed of the connecting rod 7 and the levers 6 and 8 in a state where the eccentric direction is displaced by approximately 180 °. When the 4 is rotated by an actuator, the eccentric shaft portion 4a of the one rear side support shaft 4 and the eccentric shaft portion 3a of the other rear side support shaft 3 are displaced laterally in the same direction to the same extent. If this is done, the object of the present invention can be achieved. Therefore, it is not always necessary to displace the left and right eccentric shaft portions by 180 °, and as shown in FIG. 6, the eccentric shaft portions 3a of the left and right rear support shafts 3, 4 are 4a
It is natural that the eccentric directions may be linked to each other in the substantially same direction so that both of them are substantially upward or substantially downward, respectively. Reference numeral 4 always rotates in the same direction, and the eccentric shaft portions 3a and 4a are also displaced in the same direction, and can perform the same function as that of the embodiment shown in FIGS. In FIG. 6, the structure other than the above is the same as that of the embodiment of FIGS. 1, 2 and 4 and 5,
The same reference numerals as those in FIG. 1 represent the same parts.

Further, in the above embodiment, the left and right rear suspension links 10
An example in which the shaft supporting the base end of the vehicle body side member is constituted by an eccentric shaft, and the rear wheel steering is performed by displacing only the rear suspension link to the left and right by the rotation of the eccentric shaft. However, instead of the left and right rear suspension links 10, a shaft for supporting the base end portions of the left and right front suspension links 9 on the vehicle body side is constituted by an eccentric shaft, and the eccentric shaft is rotated. The rear wheel steering may be performed by displacing only the front suspension link 9 left and right.

As described above, according to the present invention, in the double-link type rear suspension in which the rear wheels are supported by the front and rear suspension links so that the rear wheels can be vertically swung, one of the front side and the rear side is provided. The rear wheel can be accurately steered with an extremely simple structure that only rotates the shaft that supports the suspension link on the vehicle body side member, and the overall size of the device is made smaller and the cost is significantly reduced. In addition to the above, it is possible to accurately control the small angle steering of the rear wheels, and it is possible to bring about a great effect in practical use.

[Brief description of drawings]

FIG. 1 is a front view of the embodiment of the present invention seen from the rear side, FIG. 2 is a sectional view taken along the line A--A of FIG. 1, and FIG. 3 is a rear wheel steering system shown in FIGS. Plane explanatory view for explaining the steering function, fourth
FIG. 5 and FIG. 5 are vertical cross-sectional side views of essential parts showing the attachment states of the left and right rear suspension links to the rear wheel steering system. FIG. 6 is a front view showing another embodiment of the present invention as seen from the rear side. 1 …… Suspension cross member, 2 …… Rear wheel steering device case, 3,4 …… Rear side support shaft, 9,10 …… Suspension link, 11 …… Front side support shaft, 13 …… Drive shaft, 14 …… Under guard, 15 …… Slip bush.

Claims (2)

[Scope of utility model registration request] 1. The front and rear suspension links are mounted so that the base ends thereof can be pivotally mounted on a vehicle body member, and the left and right rear wheels can be vertically swung by the front and rear suspension links, respectively. In the double link type rear suspension supported as described above, the shaft that supports the base end portion of either one of the front side and the rear side of the suspension link on the vehicle body side member can rotate one end on the vehicle body side member. And the other end is eccentric to the eccentric shaft, and the base end of the one suspension link is rotatably fitted to the eccentric shaft via a slide bush to support the left and right sides. An actuator that links the eccentric shaft portion of the shaft with a link member in a state where the eccentric direction of the left and right eccentric shaft portions is displaced by about 180 °, and that operates in accordance with steering of the front wheels to rotate the left and right support shafts. Set up The left and right support shafts are rotated by the operation of the actuator, and the rear wheels are steered by displacing only one of the front and rear suspension links in the left and right directions. Rear wheel steering system. 2. The vehicle rear wheel steering system according to claim 1, wherein the eccentric shaft portions of the left and right support shafts are displaced by a link member in the eccentric direction of the left and right eccentric shaft portions by approximately 180 °. The rear wheel steering system for a vehicle, characterized in that the eccentric shaft portions of the left and right support shafts are linked by a link member in such a manner that the eccentric shaft portions of the eccentric shaft portions are oriented substantially in the same direction. .