JPH0635703Y2 - Suspension device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a suspension device, particularly a rigid axle type suspension device for a vehicle including a leaf spring, and more particularly to a mounting structure of the leaf spring to an axle beam of a vehicle. Is.

[Prior Art] For example, in a suspension device used for a front suspension of a truck or the like, as shown in FIG. 3, an axle beam (also called an I beam) 11 of a truck 10 is used.
A leaf spring 15 is attached to the spring seat 14 of the above, and the leaf spring 15 is arranged inside the tire 12. An example of this type of suspension device is disclosed in Japanese Utility Model Laid-Open No. 59-27904.

[Problems to be Solved by the Invention] In the case of the conventional suspension device, since the tires 12 are steered wheels, the tires are naturally steered more than the rear tires. Therefore, the leaf springs 15 are prevented from interfering with the tires 12. Must be placed. That is, the leaf spring 15 is located far inside the tire 12, that is, the distance D1 from the center line (wheel center) HC of the tire 12 in the axle direction.
Will be placed. Along with this, the spring distance C between the left and right leaf springs 15 was also narrowed.

For this reason, since the bending moment in the up-down direction acts largely on the axle beam 11 by the amount of the distance D1, particularly in the case of a heavy-duty vehicle such as a truck, a sufficient thickness (cross-sectional area) to support the bending moment. As a result of the demand for the axle beam 11, the minimum ground clearance is decreased and the unsprung weight is increased.

Further, since the spring interval C is narrow, it is difficult to secure both the roll rigidity and the riding comfort. That is, since the roll rigidity is determined by the spring interval C and the spring constant of the leaf spring 15, in order to secure a predetermined roll rigidity, conventionally, there is a portion where the ride constant is sacrificed by setting a high spring constant. there were.

Further, since the leaf spring 15 is on the axle beam 11, the roll center RC is located at the center of gravity of the vehicle as shown in FIG.
It is in a much lower position than CG. Therefore, the roll moment RM during turning tends to increase, and the roll angle θ
Grows larger. That is, the roll moment is RM, the centrifugal force acting on the vehicle center of gravity CG is F, the vehicle center of gravity CG and the roll center RC.
If the distance is D2, the roll moment is expressed by RM = F × D2. Therefore, when the distance D2 is large, the roll moment RM becomes large, and as a result, the roll angle θ becomes large and the turning stability is impaired.

[Means for Solving the Problems] In the suspension device of the present invention for solving the above problems, the spring seat of the leaf spring is set at a high position above the axle beam to avoid interference between the steered tire and the leaf spring. By doing so, it is possible to expand the spring spacing of the left and right leaf springs,
The distance between the roll center and the center of gravity of the vehicle is reduced.

Specifically, in a rigid axle type suspension device for a vehicle including a leaf spring, a mounting member is provided so as to project on an axle beam of the vehicle. A spring seat for mounting the leaf spring is provided on the upper end of the mounting member. This spring seat is set at a position higher than the upper end of the tire of the vehicle.

[Operation] According to the above means, the leaf spring is arranged at a position higher than the upper end of the tire, whereby interference between the steered tire and the leaf spring is avoided, and the spring interval between the left and right leaf springs is expanded. It will be possible.

Further, by disposing the leaf spring at a high position, the roll center is located above and the distance between the roll center and the center of gravity of the vehicle is reduced.

[Embodiment] An embodiment of the present invention will be described below.

First Embodiment First, a first embodiment will be described with reference to FIG. 1 in which a front view of an axle beam of a rigid axle type front suspension device for a vehicle such as a truck is shown.

The axle beam 1 of the truck is provided with left and right tires 2 steered via steering devices (not shown) at both ends thereof.

At both ends of the axle beam 1, rod-shaped attachment members 3 adjacent to the inside of the tire 2 are integrally fixed in a vertical shape. It is desirable that the mounting member 3 be provided at a position as close as possible to the center line HC of the tire 2.

A spring seat 4 for mounting the leaf spring 5 is provided on the upper end of the mounting member 3. The spring seat 4 is set at a position higher than the upper end of the tire 2.

On the spring seat 4, the central part of the leaf spring 5 is attached via a bolt or the like. Although not shown, both ends of the leaf spring 5 are attached to the vehicle frame via spring hangers or shackles as is well known.

According to the suspension device, the leaf spring 5
Is arranged at a position higher than the upper end of the tire 2, so that interference of the steered tire 2 with the leaf spring 5 is avoided. As a result, the distance D1 between the tire 2 and the leaf spring 5 can be shortened as compared with the conventional one, and the spring distance C between the left and right leaf springs 5 can be widened.

Therefore, since the vertical bending moment acting on the axle beam 1 is reduced, it becomes possible to reduce the thickness of the axle beam 1, that is, the cross-sectional area.
It is possible to increase the minimum ground clearance and reduce the unsprung weight.

Further, by widening the spring interval C between the left and right leaf springs 5, the ride comfort can be improved while ensuring the roll rigidity. That is, since the roll rigidity is increased by expanding the spring interval C, if the same roll rigidity as the conventional one is to be obtained, the spring constant of the leaf spring 5 is set to correspond to the expansion of the spring interval C. The ride comfort is improved by being able to set it low.

Further, by disposing the leaf spring 5 at a position higher than that of the conventional one, the roll center RC is located above, and the distance D2 between the roll center RC and the vehicle center of gravity CG is reduced. As a result, the roll moment when turning is
From the above equation RM = F × D2, the smaller the distance D2, the smaller the value. As a result, the roll angle θ (see FIG. 4) becomes smaller and the turning stability is improved.

[Second Embodiment] Next, a second embodiment will be described with reference to FIG.

Since this example is a modification of part of the first embodiment, the same parts are designated by the same reference numerals, and the description thereof will be omitted. Only different configurations will be described in detail.

That is, the upper end portion of the mounting member 3 of the first embodiment extends outward along the axial direction of the axle beam 1, the spring seat 4 is provided above the tire 2, and the leaf spring 5 is provided above the tire 2. It was done.

According to the suspension device of the present embodiment, the same operational effects as those of the first embodiment can be obtained, and the spring interval C of the leaf spring 5 is further expanded than that of the first embodiment, that is, the maximum (the vehicle width is close to the limit). Since the roll rigidity is further increased, the roll rigidity can be further increased, the turning stability can be improved, and the riding comfort can be improved.

It should be noted that although the front suspension device is shown in both of the above-described embodiments, the present invention may be applied to the rear suspension device as well.

[Advantages of the Invention] According to the suspension device of the present invention, the interference between the leaf spring and the tire can be avoided and the spring interval between the left and right leaf springs can be widened, thereby reducing the vertical bending moment acting on the axle beam. Accordingly, the thickness of the axle beam can be reduced, the minimum ground clearance can be increased, and the unsprung weight can be reduced. At the same time, the riding comfort can be improved while ensuring the roll rigidity.

Further, since the distance between the roll center and the center of gravity of the vehicle is reduced, the roll moment is reduced and the turning stability is improved.

[Brief description of drawings]

FIG. 1 is a front view of an axle beam showing a first embodiment of the present invention, and FIG. 2 is a front view of an axle beam showing a second embodiment of the present invention. FIG. 3 is a front view of a truck showing a conventional example, and FIG. 4 is a front view showing a rolling state of the truck. 1 ... Axle beam 2 ... Tire 3 ... Mounting member 4 ... Spring seat 5 ... Leaf spring

Claims (1)

[Scope of utility model registration request] 1. A rigid axle suspension system for a vehicle, comprising a leaf spring, wherein a mounting member is projected on an axle beam of the vehicle, and a spring seat for mounting the leaf spring is provided at an upper end portion of the mounting member. A suspension device in which this spring seat is set at a position higher than the upper ends of the tires of the vehicle.