KR20040048643A - torsion beam type suspension - Google Patents

Abstract

PURPOSE: A suspension system is provided to improve the under steer characteristic by increasing the vertical toe-in while maintaining the over steer amount by restricting the vertical movement of a mounting portion in a trailing arm. CONSTITUTION: The vertical movement of a mounting portion in trailing arms(22,22¡~) is restricted by connecting left and right joints(26,26¡~) through a roll bar(30). The roll bar is folded after extending from the left and the right joints forward a vehicle. Thereby, the vertical toe-in is increased while the over steer amount is maintained.

Description

Torsion beam type suspension

The present invention relates to a torsion beam suspension system.

Suspension of a vehicle is a device that connects the vehicle body and the wheel, and absorbs the shock or vibration received from the road surface while driving to improve the ride comfort and stability of the vehicle. These suspensions are largely divided into one-piece in which the left and right wheels are connected to the axle and the independent type in which the left and right wheels operate separately. It consists of a shock absorber and an arm or a link that controls the operation of the wheel.

The torsion beam suspension, which is a standalone type, combines the left and right trailing arms into a single member called a torsion beam or a cross beam, and because of the simple components, low production cost and low It has been used in light and quasi-rear suspensions for decades with relatively high running stability relative to mass.

In the conventional torsion beam suspension device, as shown in FIG. 1, a pair of left and right trailing arms 2 and 2 'are connected by the torsion beam 4, and the trailing arms 2 and 2' are connected to each other. The front end pivotally supports the vehicle body (not shown) by the joints 6 and 6 'with rubber bushings, and the wheels 8 and 8' are coupled to the rear ends of the trailing arms 2 and 2 '. Structure. In addition, a suspension spring (10.10 ') is provided between the trailing arms (2, 2') and the vehicle body, and shock absorbers (12, 12 ') are provided at the rear end of the trailing arms (2, 2'). Is connected.

The torsion beam suspension configured as described above is characterized in that the wheels 8 and 8 'are deformed due to the torsional deformation characteristics of the torsion beam 4, and the torsional deformation and the position of the trailing arm and the bushing characteristics are bumped. Toe-in: When looking down from the top of the wheel, the distance between the front of the two wheels is smaller than the rear distance.

By the way, the torsion beam suspension is a suspension that is a conflict in terms of various performance. That is, the roll steer, the lateral steer and the longitudinal steer should be harmonized with each other within an appropriate range. In a torsion beam suspension, generally, the lateral steer and the long twin steerer All toe-outs (when the wheels are viewed from the top, the distance between the front of the two wheels is greater than this rear distance) will be oversteer.

Therefore, in order to offset such a result, a roll steer must be made large, which is also not a good situation. For larger roll steer, the torsion stiffness of the torsion beam should be lowered or the bushing coupled to the trailing arm should be made of hard material. However, this change in suspension results in both the lateral steer and the longitudinal steer growing to the toe-out side, resulting in an overall suspension system that remains the same. derivation towards the understeer becomes impossible.

In the conventional torsion beam suspension shown in Fig. 2, for example, the left wheel 8 is bumped and the left wheel 8 'is rebounded. In this case, the right wheel 8 moves upward because the bump condition and the left wheel 8 'moves downward because the rebound condition. At this time, the joints 6 and 6 ', which are the mounting positions of the trailing arms 2 and 2', move in the opposite direction to the wheels 8 and 8 'with the torsion beam 4 as the axis, so that the joint 6 is It moves downward and the joint 6 'moves upward.

At this time, in the torsion beam suspension device, the amount of roll steer is reduced due to the downward movement of the joint 6 and the upward movement of the joint 6 '. This means that by restraining the position of the joints 6, 6 ′ the roll steer amount can be increased. At this time, even if the up and down movement of the joints 6 and 6 'is restrained, the transverse and longitudinal characteristics are hardly changed. Therefore, the oversteer through the transverse and longitudinal toe-outs is restricted by the up and down constraints. The amount of understeer can be increased by increasing the toe-in in the vertical direction while maintaining the amount. As a result, the amount of understeer of the overall suspension system can be increased.

However, in order to reduce the amount of bushing deformation of the mounting portion of the trailing arm, the up and down stiffness of the bushing may be increased. However, if the bushing stiffness is increased, a larger load is applied to the bushing, which may cause the durability of the bushing.

An object of the present invention is to constrain the vertical movement of the mounting arm of the trailing arm as described above to increase the toe-in in the vertical direction while maintaining the oversteer amount, thereby increasing the understeer characteristics. It is to provide a torsion beam suspension.

1 is a perspective view showing a conventional torsion beam suspension device;

Figure 2 is a schematic diagram (top view) showing a conventional torsion beam suspension system,

3 is a schematic view (top view) showing a torsion beam suspension device according to a first embodiment of the present invention;

4 is a schematic view (top view) showing a torsion beam suspension device according to a second embodiment of the present invention;

5 is a view showing an installation position of the roll bar of FIG.

<Explanation of symbols for the main parts of the drawings>

22, 22 ': trailing arm 24: torsion beam

26, 26 ': Joint 28, 28': Wheel

30, 130: roll bar

The present invention for achieving the above object is a torsion beam suspension device in which a pair of left and right trailing arms are connected by a torsion beam, and the front end of the trailing arm mounts the vehicle body by a joint. The joint is connected by a roll bar.

The roll bar is bent after extending from the left and right joints to the front of the vehicle. The roll bar may be bent after extending from the left and right joints to the rear of the vehicle.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

3 shows a first embodiment of the present invention. As shown, a pair of left and right trailing arms 22, 22 'are connected by torsion beams 24, and the front ends of the trailing arms 22, 22' are jointed with rubber bushings. 26 ') to pivotally support the vehicle body (not shown), and wheels 28 and 28' are coupled to the rear ends of the trailing arms 22 and 22 '. The suspension spring, shock absorber and the like are the same as those in FIG.

The left and right joints 26 and 26 'are connected by roll bars 30. The roll bar 30 extends in front of the vehicle from the left and right joints 26 and 26 'and is then bent to form a c shape as a whole. The cross-sectional shape of the roll bar 30 is the same as the roll bar used in the general suspension.

The roll bar 30 installed as described above does not restrain the left and right and front and rear movements of the mounting portions (joints 26 and 26 ') of the trailing arms 22 and 22', but reduces the amount of deformation with respect to the up and down reverse movement. Restrain. Therefore, the upper and lower deformations of the trailing arms 22 and 22 'can be reduced, so that the amount of roll steer can be increased in the left and right reversed cornering situation, thereby improving the understeer characteristics.

The roll bar 30 is connected to the vehicle body via a roll bar mounting bushing (not shown). Thus, the trailing arms 22, 22 ′ are connected to the vehicle body via the joints 26, 26 ′ and the roll bar mounting bushings, so that the force resulting from the deformation of the trailing arms 22, 22 ′ is applied to the joints 26. , And divided into itself through the roll bar 30 and the load is applied. This disperses the load applied to the joint, thereby increasing the durability of the joint.

4 shows a second embodiment of the present invention. In the present embodiment, the roll bar 130 is bent after being extended to the rear of the vehicle from the left and right joints 26 and 26 '. The rest of the configuration is the same as that of FIG.

On the other hand, the roll bar 30 of the present invention is installed between the fuel tank (T) and the trail arms (22, 22 '), as shown in Figure 5, so that the oil leakage of the fuel tank (T) during rear collision You can perform additional functions to prevent this. That is, since the suspension of the suspension device is prevented by the roll bar 30 installed vertically during the forward movement of the suspension device due to the rear collision, an additional fuel tank protection beam is unnecessary.

According to the torsion beam suspension according to the present invention, the understeer characteristic is increased by constraining the vertical movement of the mounting arm of the trailing arm to increase the toe-in in the vertical direction while maintaining the oversteer amount. Can increase.

In addition, since the load applied to the joint is distributed, the durability of the joint is increased, and the movement of the suspension device is prevented by the roll bar installed vertically during the forward movement of the suspension device due to the rear collision, so that an additional fuel tank protection beam is unnecessary.

Claims (3)

In a torsion beam suspension device in which a pair of left and right trailing arms are connected by a torsion beam, and the front end of the trailing arm mounts the vehicle body by a joint. The left and right joints are torsion beam-type suspension, characterized in that connected by a roll bar. The method of claim 1, The roll bar is a torsion beam suspension, characterized in that bent after extending to the front of the vehicle in the left, right joint. The method of claim 1, The roll bar is a torsion beam suspension, characterized in that bent after extending to the rear of the vehicle from the left, right joint.