JPS6251189B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a vehicle steering system that steers both the front wheels and the rear wheels.

The present applicant has previously provided a vehicle steering device in which front wheels and rear wheels can be steered by steering operation of a steering wheel. Basically, such a device connects the front wheel steering mechanism and the rear wheel steering mechanism with a linkage member such as a linkage shaft, and moves the rear wheels in the same direction as the front wheels by operating a small steering angle of the steered wheels. In addition, a steering angle function generating mechanism is configured to steer the vehicle in the opposite direction in the case of a large steering angle operation, or to return the steering angle of the rear wheels to zero in the latter case.

By the way, in this type of vehicle, the rear wheels are independently suspended, and the lower arms that make up the rear wheel suspension mechanism may be lengthened depending on the suspension characteristics. In this case, the bearings of the left and right lower arms are placed near the center line of the vehicle body.
Therefore, the tie rods for steering the left and right rear wheels are also disposed opposite to each other near the center line of the vehicle body, so it is desirable to make the rear wheel steering mechanism more compact, especially in the vertical direction from the viewpoint of the vehicle body structure.

On the other hand, in addition to realizing a vibration-proof structure that prevents vibrations applied to the rear wheels from being transmitted to the vehicle body via the rear wheel steering mechanism, the joint member that connects the left and right rear wheel steering tie rods is designed to provide the right and left oscillation necessary for steering. It is even more preferable to extend the life of the vibration isolating material interposed between the restraining member that restrains the vehicle body and the vehicle body.

The present invention has been made to rationally match the above, and its purpose is to provide a crank portion on the shaft member of a rear wheel steering mechanism connected to the front wheel steering mechanism via a linkage member, loosely fitting the crank pin of the crank part into the joint member,
Further, tie rods for steering left and right rear wheels are connected to the joint member, and the joint member is restrained and supported by a restraining member consisting of a link member pivotally supported on the vehicle body and an arm member pivotally supported by the link member. This allows each component of the rear wheel steering mechanism to be arranged compactly without taking up space in the vertical direction, and furthermore, it is possible to arrange the components of the rear wheel steering mechanism in a compact manner without taking up space in the vertical direction, and furthermore, it is possible to provide a pivot point between the arm member that restrains and supports the joint member and the link member, and between the link member and the vehicle body. A rubber bush is inserted in each of the pivot parts of the link member to realize a vibration-proofing structure in these parts, and the center-to-center distance of each pivot between the arm member of the link member and the vehicle body is made larger than the center-to-center distance between the shaft member and the crank pin. By configuring it as such, it is possible to reduce the rotational angle of the link member and the arm member around the pivot portion, thereby reducing the torsional rotational angle of the rubber bushings interposed in the respective branch portions, thereby increasing the lifespan of these rubber bushings. An object of the present invention is to provide a vehicle steering device that can be used in a variety of ways.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Note that FIG. 1 is an explanatory plan view of a four-wheeled vehicle equipped with the steering device of the present invention, and FIGS.
The figures are a side view and a rear view, and FIG. 4 is an enlarged perspective view showing the basic configuration of the main parts according to the present invention.

The steering rotation of the steering wheel 1, which is a steering wheel, is converted to the left and right movement of the tie rods 4, 4 for steering the front wheels 3, 3 via a rack-and-pinion type steering gear 2 equipped with power steering. Knuckle arms 5, 5 connected to the outer ends of
The front wheels 3, 3 are also steered by this rotation.

A linkage member 6 is connected to approximately the center of the steering gear 2, and a linkage shaft 9 is extended to the rear of the vehicle body via a universal joint 8 to a pinion shaft 7 that easily meshes with it, and is further extended to the rear via a universal joint 10. Ring 11,1
A shaft member 12 constituting one steering mechanism is connected.

The shaft member 12 is disposed on the center line of the heavy body with its rear part downwardly disposed, and a crank part 13 is provided at the rear end thereof, and a crank pin 14 of the shaft member 12 is formed to protrude rearward. Such shaft member 1
2 is inserted and supported within a shaft collar 16 fixedly integrated with a rear wheel lower arm bracket 15 provided on a cross member of the vehicle body frame.

That is, as shown in FIG. 5, between the shaft collar 16 fixed to the bracket 15 and the shaft holder 17 of the shaft member 12 supported within this 16, there are two front and rear parts as shown in FIG. A rubber bush 18 is interposed, and the shaft holder 17 is press-fitted into the shaft collar 16 via these rubber bushes 18,18. In this way, the shaft member 12 is rubber-mounted to the vehicle body and is therefore supported in a floating manner.

5 and 6, the direction in which the cross section of the shaft collar 16 is shown is reversed.

A joint member 20 having an approximately inverted T-shape in the front is loosely fitted into the crank pin 14 of the crank portion 13 provided on the shaft member 12 with its upper part 21, and protrusions 2 forming lower portions on both left and right sides of the joint member 20 are fitted loosely.
Rear wheel steering tie rods 23, 23 are provided with ball joints 24, 24 on the upper surfaces 22a, 22a of the wheels 2, 22, respectively.

On the other hand, a link bracket 25 is fixedly hung down from the rear side of the joint member 20 on one side of the floor panel of the vehicle, and a link member 26 is attached to this 25.
is suspended from a pivot. An arm member 27 is pivotally attached to the lower part of the link member 26.
is formed sufficiently long beyond the center line of the vehicle body, and both left and right protrusions 22 of the joint member 20,
The tip portion 27a of the arm member 27 is fixed to the rear surface portions 22b, 22b of the arm member 22 with two bolts 28, 28. As a result, the joint member 20 performs a combined rocking motion of vertical and horizontal movements in conjunction with the crank movement of the crank pin 14.

And link member 26 and link bracket 25
A rubber bushing 30 is interposed at the pivot point between the link member 26 and the arm member 27, and a rubber bush 31 is also interposed at the pivot point between the link member 26 and the arm member 27.

That is, as shown in FIG. 7 (cross-sectional view taken along the line 7-7 in FIG. 4), the front and rear hanging pieces 25 of the link bracket 25, which has a horizontal U-shaped cross section, are fixed to the floor panel of the vehicle body.
The upper part of the link member 26 faces between a and 25b, and the link member 26 is pivoted to the link bracket 25 with a bolt and nut 34 via a rubber bush 30 that is press-fitted and baked between the large and small diameter cylinders 32 and 33. Therefore, it is suspended from the vehicle body in an elastic manner. In this case, by tightening the bolt/nut 34, the small diameter cylinder 33 is integrated with the bracket 25, and the large diameter cylinder 32 is integrated with the link member 26.

Further, the lower part of the link member 26 is made to face between the front and rear pieces 27b and 27c forming one end of the arm member 27, and the rubber bushing 31 which is press-fitted and baked between the large diameter and small diameter cylinders 35 and 36 in the same manner as above is attached. The arm member 27 is pivotally supported on the link member 26 by the bolt/nut 37, and thus the arm member 27 is also in an elastic state. In this case as well, the small diameter cylinder 36 is integrated with the arm member 27 by tightening the bolt/nut 37, and the large diameter cylinder 35 is integrated with the link member 26.

Therefore, both the rubber bushes 30 and 31 are circumferentially rotated by the relative rotation of the large diameter cylinders 32 and 35 and the small diameter cylinders 33 and 36 in opposite directions as the link member 26 and the arm member 27 swing and rotate. Twist and rotate in the direction.

In the present invention, the center-to-center distance l between the center of the pivot portion 34 of the link member 26 with the link bracket 25 and the center of the pivot portion 37 of the arm member 27 pivotally supported by the link member 26 is defined as the center-to-center distance l of the shaft member 12. The center-to-center distance between the core and the center of the crank pin 14 offset therefrom is larger than ε (l>ε). This is shown in FIG.

In FIGS. 1 to 3, 19 is a knuckle arm connected to the outer end of the tie rod 23 for steering the rear wheels, and 29 is a lower arm for the rear wheels.

Next, the operation of the above steering system will be described.

First, when the steering wheel 1 is in the neutral position when the vehicle is traveling straight, the crank portion 13 is connected to the crank pin 1.
For example, it is in a vertical state with 4 facing downward.

For example, when steering wheel 1 is steered to the right, front wheel 3
is similarly steered to the right, and the shaft member 12 is rotated to the right (clockwise) when viewed from the rear of the vehicle via the linkage member 6 consisting of the pinion shaft 7 and linkage shaft 9 led out from the steering gear 2. As a result, the crank pin 14 of the crank portion 13 similarly rotates clockwise, and the joint member 20 loosely fitted onto the pin 14 first swings to the left. Therefore, the tie rods 23, 23 connected to both the left and right protrusions 22, 22 of the joint member 20, which forms a substantially inverted T-shape from the front, move to the left, the knuckle arms 19, 19 rotate clockwise, and the rear wheel 11 moves toward the front wheel 3. At the same time, the ship is steered to the right.

When the crank pin 1 becomes horizontal to the left, the right steering amount of the rear wheel 11 becomes maximum, and from then on, the crank pin 1 becomes horizontal.
Joint member 2 until 4 is vertically upward.
Due to the rightward rocking of 0, the right steering amount of the rear wheel 11 gradually decreases to zero.

When the pin 14 further cranks clockwise, the joint member 20 swings further to the right from the neutral position, and the rear wheel 11 then moves to the left in the opposite direction to the front wheel 3 until the pin 14 becomes horizontal to the right. The steering wheel is steered with a gradually increasing amount of steering.

Then, the joint member 20 swings leftward until the pin 14 reaches the downward vertical position again, exceeding the above-described state in which the left steering amount is at its maximum.
The left steering amount gradually decreases to zero. The left steering is done in the same way.

In this way, a small steering angle operation of the steered wheel 1 (up to 180 degrees from the neutral position of the crank pin 14 at 0 degrees) moves the rear wheel 11 in the same direction as the front wheels 3, and a large steering angle operation (from 180 degrees to 360 degrees) In the above), a steering angle function generating mechanism was constructed which can steer the vehicle in the opposite direction, or in the latter case, return the steering angle of the rear wheels 11 to zero.

Moreover, the vehicle steering system of the present invention capable of generating the above-mentioned steering angle function has a joint member 20 loosely fitted to the crank pin 14, which is a small component with a substantially inverted T-shape when viewed from the front.
Make a mold, and hold this 20 at the upper part 21 and attach it to the pin 1.
4, and the upper surface portion 2 of the protrusions 22, 22 forming the lower portions of the left and right sides of the joint member 20.
Tie rods 23, 23 for rear wheel steering are attached to 2a and 22a.
are connected to each other, and further the rear surface 2 of the protrusions 22, 22 is connected to each other.
An arm member 27 is connected to 2b and 22b, and the arm member 27 is pivotally supported by a link member 26 hanging biased toward the rear part of the joint member 20 on one side of the floor panel of the vehicle. .

Therefore, the lower arm 29 that constitutes the rear wheel suspension mechanism
is made longer depending on the suspension characteristics, so the bearings of the left and right lower arms 29, 29 are placed near the center line of the vehicle body,
Along with this, tie rods 23, 23 for rear wheel steering
They can also be compacted and placed facing each other near the centerline of the vehicle body, and compactness in the vertical direction, which is particularly desirable from the standpoint of vehicle body structure, can be achieved.

In addition, a shaft member 12 supported by the vehicle body, a link member 26 and an arm member 27 which are restraining members
are mounted or pivoted through rubber bushes 18, 30 and 31, respectively, so that the rear wheels 11, 11
It is possible to prevent vibrations applied to the vehicle body from being transmitted to the vehicle body through the rear wheel steering mechanism, thereby making the steering system excellent in terms of anti-vibration measures.

Furthermore, in the present invention, since the center-to-center distance l of the pivot parts 34 and 37 between the link member 26 and the vehicle body and the arm member 27 is set larger than the center-to-center distance ε between the shaft member 12 and the crank pin 14 (l>ε), the following is satisfied. It is possible to demonstrate the following characteristics.

That is, since l>ε, the rotation angle of the link member 26 and the arm member 27 around the pivot parts 34 and 37 becomes smaller with respect to the rotation angle of the crank pin 14 around the shaft member 12, compared to the case where l=ε. Therefore, the torsional rotation angle of the rubber bushes 30, 31 interposed in the respective pivot parts 34, 37 can be reduced. Therefore, these rubber bushes 30 and 31
It is possible to plan to extend the lifespan of the

In the above, the maximum value of l is appropriately set in consideration of the above-mentioned compactness.

By the way, in this embodiment, since the link bracket 25 is fixedly suspended from the floor panel of the vehicle, the rubber bushes 3 of the respective pivot parts 34 and 37 of the link member 26 and the arm member 27 that are pivotally supported on such parts are
0 and 31 are preferably made of soft rubber from the viewpoint of the vehicle body structure, but according to the present invention, the link members 26
Since the rotation angle of the arm member 27 can be reduced, even if the spring constant of the rubber bushes 30 and 31 is lowered, it is easy to maintain strength and durability without causing fatigue, and the spring constant is sufficiently low to isolate vibrations in this part. Rubber bushings 30 and 31 with a handle can be used.

Generally, if the rigidity around the king pin K of the rear wheels 11 is not sufficiently high, the actual steering angle will be smaller than the steering angle, making it impossible to achieve desired steering performance. However, according to the present invention, even if the spring constant of the bushes 30 and 31 is sufficiently low, the load acting on the link member 26 and the arm member 27 is small,
Even if the displacements at 4 and 37 are large, they will hardly affect the displacement of the joint member 20, especially the left-right rocking of the joint member 20, which directly controls the steering angle around the kingpin K of the rear wheel 11. There is an advantage that there is no such thing.

In addition, the joint member 20 is composed of a small part with a substantially inverted T-shape from the front, and an arm member 27 that ensures the rocking of the joint member 20 is suspended from the vehicle body on one side of the joint member 20 with a biased rearward link. Since it is pivoted to the member 26, it is possible to reliably downsize the joint member 20, which requires great strength, and at the same time, a large load is not applied to the arm member 27, which is a large part, so that it has strength. The thickness of the device can be reduced without any problems, and the overall weight of the device can also be reduced.

As is clear from the above description, according to the present invention, each component of the rear wheel steering mechanism can be arranged in a compact manner without taking up space in the vertical direction, and at the same time exhibits an excellent vibration damping effect. In particular, since the center-to-center distance of each pivot point between the link member and the vehicle body and arm member is made larger than the center-to-center distance between the shaft member and the crank pin, this process contributes to extending the life of the rubber bushings interposed in each pivot point. It can demonstrate various features such as being extremely large.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory plan view of a vehicle equipped with the steering system of the present invention, FIG. 2 is a side view of the same, FIG. 3 is a rear view of the same, and FIG.
The figure is an enlarged perspective view showing the basic configuration of the rear wheel steering mechanism.
Figure 5 is a vertical cross-sectional side view of the shaft collar attachment part.
6 is a partially cutaway side view of the shaft member assembly portion, FIG. 7 is a sectional view taken along the line 7-7 in FIG. 4, and FIG. FIG. In the drawing, 1 is a steering wheel, 3 is a front wheel, 11 is a rear wheel,
12 is a shaft member, 13 is a crank portion, 14 is a crank pin, 20 is a joint member, 23 is a tie rod for rear wheel steering, 26 is a link member, 27 is an arm member, 30 and 31 are rubber bushes, ε, l
is the center-to-center distance.

Claims (1)

[Claims] 1. In a vehicle steering device in which the rear wheels are steered together with the front wheels by the steering operation of the steering wheel, the steering device is loosely fitted into a crank pin of a crank part provided on a shaft member that rotates in conjunction with the steering wheel, and An arm member is fastened to a joint member that connects the left and right rear wheel steering tie rods, the arm member is pivotally connected to a link member through a rubber bushing, and the link member is attached to the vehicle body through a rubber bushing. What is claimed is: 1. A steering system for a vehicle, characterized in that the arm member of the link member and the vehicle body are pivoted so that the center-to-center distance between the respective pivots is greater than the center-to-center distance between the shaft member and the crank pin.