JPH06255525A - Rear wheel steering system for trucks - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] For trucks with a rigid rear axle housing that supports the rear wheels, the rear axle housing is steered at a small steering angle in response to steering and steering of the front wheels. (EN) Provided is an inexpensive rear wheel steering device capable of improving stability. [Structure] A free end portion of both legs of a V-shaped rod member 36 is pivotally attached to a rear axle housing 16 supporting rear wheels at both end portions in the vehicle width direction, and an apex portion of the rod member is pivotally attached to a slide member. , The slide member to the cross member 42
It is slidably fitted into the arc-shaped guide groove 44. Further, a hydraulic cylinder device 46 for steering the rear wheels is provided between the rod member and the chassis frame 10, and the rear axle housing is steered by the operation of the hydraulic cylinder device.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear wheel steering device for a truck or the like.

[0002]

2. Description of the Related Art Recently, various four-wheel steering systems and devices have been proposed in which the rear wheels are steered in conjunction with the steering of the front wheels in order to improve the steering stability during high-speed traveling. Conventionally, regarding the rear wheel steering such as a truck in which the rear wheels are supported at both end portions in the vehicle width direction of a rigid axle tube or a rear axle housing, and the rear axle housing is suspended on a chassis frame through a leaf spring device, The central portion of the rear axle housing in the vehicle width direction is rotatably attached to the apex portion of the upper rod having a V-shaped planar shape, and the both free ends of the V-shaped upper rod are pivotally attached to the chassis frame. Further, one end of each of a pair of left and right lower rods arranged in the vehicle front-rear direction is pivotally mounted near both ends of the rear axle housing in the vehicle width direction, and the other ends of the lower rods are connected to a hydraulic cylinder device, respectively. By driving the left and right lower rods in opposite directions by the hydraulic cylinder device, the rear axle housing is moved to the above-mentioned V
A device has already been proposed for steering around a pivot axis at the apex of the letter-shaped upper rod.

However, in the above-mentioned proposed rear wheel steering system, since the rear axle housing is connected to the chassis frame by the V-shaped upper rod and the pair of left and right lower rods, the number of links increases and each link is connected. Since the number of ball joints connected to the rear axle housing and the chassis frame is correspondingly increased, the structure is complicated and expensive.

[0004]

SUMMARY OF THE INVENTION The present invention was devised in view of the above circumstances, and by reducing the number of links for connecting the rear axle housing to the chassis frame, it is possible to reduce the number of links for trucks and the like having a simple structure. An object of the present invention is to provide a wheel steering device.

[0005]

In order to achieve the above object, the present invention provides a chassis frame and a rear axle housing mounted on the chassis frame via suspension springs and supporting rear wheels at both ends in the vehicle width direction. , A V-shaped planar shape, both ends of which are free ends of both legs, and a rod member pivotally attached to the rear axle housing and extending in the vehicle front-rear direction, and both ends in the vehicle width direction fixed to the undercarriage frame. Is provided between the chassis frame and the rod member, and a cross member having a circular arc-shaped guide groove that slidably accommodates a slide member that extends in the direction and is pivotally attached to the apex of the rod member. And a hydraulic cylinder device for steering the rear axle housing by rotating the rod member by its operation. It is intended to propose a steering apparatus.

[0006]

According to the above-described structure of the present invention, the rear axle housing can be steered by the rod member having a V-shaped planar shape, and the longitudinal force acting on the rear axle housing during acceleration / deceleration can be carried. , Simplification of the structure is achieved.

[0007]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, reference numeral 10 denotes a chassis frame of a vehicle such as a truck, and a pair of left and right side rails 12 extending in the front-rear direction of the vehicle body, and a plurality of side rails extending in the vehicle width direction and having both ends fixed to the left and right side rails 12 described above. 1 cross member
4 and. Reference numeral 16 denotes a rear axle housing that supports a double tire type rear wheel 18 at both ends in the vehicle width direction, and 20 has a front end portion thereof pivotally attached to a shackle bracket 22 by a shackle pin 24 and a rear end portion thereof to a shackle bracket 26. The leaf spring device (suspension spring) is pivotally attached by a link 28 and a shackle pin 30.

Above the both side portions of the differential housing 32 in the rear axle housing 16,
The free ends of both legs of a rod member 36 having a V-shaped planar shape are pivotally mounted via ball joint devices 34, respectively. The apex of the rod member 36 is connected to a slide member 40 via a ball joint device 38, and the slide member 40 is formed at both ends in the chassis direction of a cross member 42 fixed to the side rails 12 of the vehicle body frame 10. It is slidably fitted in the arc-shaped guide groove 44.

The hydraulic cylinder device 4 is provided between the top of the rod member 36 and the side rail 12 of the chassis frame 10.
6 is interposed. In the illustrated embodiment, the piston shaft 48 of the hydraulic cylinder device is the ball joint device 38 (or the slide member 40) at the top of the rod member.
A cylinder 50 is pivotally attached to a bracket 52 fixed to the side rail 12 of the chassis frame.

On the other hand, upper and lower seats 54 and 56 are provided on the upper and lower side surfaces of the rear axle housing 16 near both ends in the vehicle width direction, and spacers 58 are provided at the front and rear ends of the upper and lower seats 32 and 34. They are arranged respectively.

The front and rear spacers 58 and the upper and lower sheets 5
A U bolt 60 is inserted through 4 and 56, and a nut 62 is screwed onto the U bolt 60 and tightened,
The rear axle housing 16 is attached to the leaf spring device 20.

As well shown in the horizontal sectional view of FIG. 4 and the vertical sectional view of FIG. 5, a cylinder centered on a point A on the center line 0-0 of the vehicle front-rear direction is provided on the upper and lower surfaces of the rear axle housing 16. A protrusion 66 having a surface 64 is fixed, and a guide member 70 having a concentric cylindrical surface 68 cooperating with the cylindrical surface 64 is fixed to the upper and lower sheets 54 and 56, respectively.

Further, a rubber pad 72 is interposed between the front and rear spacers 58 and the front and rear side surfaces of the rear axle housing 16 which are opposed to each other, and by compressing the rubber pad 72, the rear axle housing 16 is formed as shown in FIG.
As shown in FIG. 3, the leaf spring device 20 is configured to be rotatable or steerable about the center of rotation A with respect to the leaf spring device 20. The rubber pad 72 is baked and fixed to the side surface of the spacer 58, for example.

An example of a concrete structure of the ball joint devices 34 and 38 is illustrated in FIG. Reference numeral 7 in the figure
Reference numeral 4 denotes one member that causes relative rotational displacement, that is, the rod member 36 or the piston rod 48, and 76 denotes the other member, for example, a bracket 78 on the rear axle housing 16. A shaft 82 having a spherical member 80 is supported by the other member 76, and a ball seat 84 that abuts the spherical member 80 is supported by the one member 74.
With this configuration, one member 74 can freely rotate with respect to the other member 76 in a plane orthogonal to the axis of the shaft 82 and in a plane including a coaxial line.

Finally, FIG. 7 shows the hydraulic cylinder device 46.
It is a conceptual block diagram which showed an example of the apparatus which controls operation | movement of. In the figure, reference numeral 86 is, for example, a light pulse non-contact type steering angle sensor mounted on a steering shaft 88 to detect a steering angle, 90 is a vehicle speed sensor, 92 is a yaw rate sensor,
Reference numeral 94 denotes a steering angle signal from the steering angle sensor 86 and a vehicle speed sensor 90.
Is a controller for controlling the control valve 96 for operating the hydraulic cylinder device 46 by receiving the vehicle speed signal of the above and the turning signal of the yaw rate sensor 92, and 98 is a hydraulic pump. When the vehicle is traveling at high speed, the steering wheel 100
Is operated to steer the front wheels 102, the steering angle sensor 8
A controller 94 that receives the steering angle signal of 6, the vehicle speed signal of the vehicle speed sensor 90, and the turning signal of the yaw rate sensor 92.
Sends a drive signal to the control valve 96 to operate the control valve.

When the front wheels 102 are steered and steered during high-speed traveling of a truck or the like, the control valve 96 operates according to a command from the controller 94, and high-pressure hydraulic oil is supplied to the hydraulic cylinder device 46. For example, when the front wheels 102 are steered to the left, hydraulic oil is supplied to the piston left chamber of the hydraulic cylinder 50 in FIG. 1, and the slide member 40 causes the cross member 4 to move.
It slides in the arc-shaped guide groove 44 of No. 2 rightward in the drawing.

For this reason, the rear axle housing 16 via the V-shaped rod member 36 makes a small angle (usually about 1 to 3 degrees) in the counterclockwise direction about the rotation center A, that is, in the same direction as the steering direction of the front wheels 102. In-phase steered. Contrary to the above, when the front wheels 102 are steered to the right, the rear axle housing 16 rotates in the clockwise direction around the rotation center A in FIG. 1 due to the operation of the hydraulic cylinder device 46, and rotates in phase to the right. Be steered. By the in-phase steering of the rear wheels 18, as is well known in the art, steering stability during high speed traveling can be effectively improved.

When the rear axle housing 16 is steered, the projection 66 provided on the rear axle housing 16
The cylindrical surface 64 and the cylindrical surface 68 of the guide member 70 fixed to the leaf spring device 20 side cooperate to set the rotation center A of the rear axle housing. Further, the longitudinal force acting on the rear axle housing 16 during acceleration and deceleration during traveling of a truck or the like is transmitted from the rod member 36 to the cross member 42 via the slider 40 and is carried by the chassis frame 10.

According to the above structure, since the rear axle housing 16 is steered by driving the V-shaped rod member 36 by the hydraulic cylinder device 46, the number of links connecting the rear axle housing 16 and the chassis frame 10 is reduced. It is possible to reduce the number of front and rear conventional devices, and correspondingly simplify the structure and reduce the manufacturing cost.

The rod member 36 may be a V-shaped member having an integral structure, or may be formed by connecting two rod members in a V-shaped pin. Further, instead of the operation control device of the hydraulic cylinder device 46 shown in FIG. 7, a control device that directly operates the control valve 96 by the hydraulic pressure generated by the power steering booster for steering the front wheels can be adopted. Further, the hydraulic cylinder device 46 for steering the rear wheels is
Rear axle housing 1 via the V-shaped rod member 36
Since 6 is rotated around the rotation center A, it can be interposed between the rod member leg portion near the apex portion and an appropriate position of the chassis frame, not at the apex portion shown in the drawing.

[0021]

As described above, the rear wheel steering system according to the present invention is mounted on a chassis frame and suspension frames on the chassis frame to support the rear wheels at both ends in the vehicle width direction. Rear axle housing, a V-shaped planar shape, both ends of the legs of which are free ends of the rod member pivotally attached to the rear axle housing and extending in the front-rear direction of the vehicle body, and both ends in the vehicle width direction are fixed to the chassis frame. Between the chassis frame and the rod member, and a cross member having an arcuate guide groove that slidably accommodates a slide member pivotally attached to the apex of the rod member and extending in the vehicle width direction. And a hydraulic cylinder device that steers the rear axle housing by rotating the rod member by the operation of the hydraulic cylinder device. It is possible to provide a rear wheel steering apparatus structure simple and inexpensive suitable truck or the like comprising a rear axle housing, industrial is extremely beneficial.

[Brief description of drawings]

FIG. 1 is a plan view of a main part of a rear portion of a vehicle body showing an embodiment of the present invention.

FIG. 2 is a side view of a rear portion of the vehicle body shown in FIG.

FIG. 3 is a side sectional view taken along the line III-III of FIG. 1 and viewed in the direction of the arrow.

4 is a cross-sectional view taken along the line IV-IV in FIG. 2 and viewed in the direction of the arrow.

5 is a longitudinal sectional view taken along the line VV of FIG. 4 and viewed in the direction of the arrow.

6 is a perspective view of the ball joint device 34, 38 shown in FIG.
It is sectional drawing which showed an example.

7 is a schematic configuration diagram showing an example of an operation control device for the hydraulic cylinder device 46 in FIG.

[Explanation of symbols]

 10 Chassis Frame 12 Side Rails 16 Rear Axle Housing 18 Rear Wheel 20 Stacked Leaf Spring Device (Suspension Spring) 36 V-Shaped Rod Member 40 Slider 42 Cross Member 44 Guide Groove 46 Hydraulic Cylinder Device

Claims (1)

[Claims] 1. An undercarriage frame, a rear axle housing mounted on the undercarriage frame via suspension springs L to support rear wheels at both ends in the vehicle width direction, and has a V-shaped planar shape and free end portions of both legs thereof. A rod member pivotally attached to the rear axle housing and extending in the vehicle front-rear direction, and both ends in the vehicle width direction fixed to the chassis frame to extend in the vehicle width direction and pivotally attached to the apex of the rod member. A cross member having an arcuate guide groove for slidably accommodating the slid member, and the chassis member and the rod member. A rear wheel steering device, such as a truck, comprising: a hydraulic cylinder device that steers a rear axle housing.