JP2018103708A - Torsion beam type suspension - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torsion beam type suspension which can prevent the thickness of a workpiece from becoming excessively non-uniform when molding a torsion beam while allowing the desired alignment characteristic to be obtained by making the position of the shear center low or high in a center portion of the torsion beam.SOLUTION: A torsion beam type suspension 1 includes: a pair of right and left trailing arms in which a support part to a vehicle body side member is provided on one end side and a support part of a wheel is provided on the other side; and a torsion beam 12 both ends of which are supported by the trailing arm. The torsion beam is configured so that the position of the shear center of the center portion becomes lower or higher than the position of the shear center on both end portions in the front view or back view of the vehicle. The shape on the plane side of the torsion beam is formed as such a curved surface that the entire portion from the one end side to the other end side is curved in the arc shape.SELECTED DRAWING: Figure 3

Description

The present invention relates to a torsion beam suspension.

The torsion beam suspension is mainly used on the rear wheel side of the front wheel drive vehicle. A torsion beam, which is a long member, is suspended between a pair of left and right trailing arms. Wheels are supported on the trailing arm, and if the left and right wheels are independently displaced due to unevenness on the road surface, the torsion beam is twisted to allow the left and right wheels and the trailing arm to be independently displaced up and down. To do. When the road surface becomes flat, the torsion beam returns to its original shape, and the trailing arm and wheels are returned to their original positions. On the other hand, when the left and right wheels are displaced in the same phase, the left and right wheels and the trailing arm swing integrally up and down.

When the torsion beam is twisted, there is a point that becomes the center of the twist. This point is called the shear center. It is known that the position of the shear center of the torsion beam affects the steering performance of the vehicle.

For example, in Patent Document 1 [0007], when the shear center line is close to the torsion beam in a plan view of the vehicle, the fixed point at the time of torsional deformation (center point of torsional deformation) and the trailing arm are supported with respect to the vehicle. It is described that the angle formed by the axis connecting the supporting center points and the shear axis increases. Further, it is described that when the vehicle body rolls, the camber angle of the wheel on the outer ring side of the turning motion increases in the negative direction. In addition, when the angle formed by the axis and the shear center line is outwardly lowered when the vehicle is viewed from the rear, the wheel on the outer wheel side of the turning motion changes to the understeer side when the vehicle rolls. Have been described. It is described that the toe angle changes on the oversteer side when the above angle is increased outward.

Patent Document 2 describes that a first end section and a second end section are provided at both ends of the trailing arm. And, in the first end section and the second end section, it is described that the shear centerline in the intermediate section of the trailing arm is lowered or increased so as not to affect the welding to the trailing arm. Has been.

Japanese Patent No. 3622540 Japanese Patent No. 4448540

In the torsion beam in the rear suspension device of Patent Document 1, the boundary between the left and right end portions and the central portion is bent. For this reason, when the torsion beam is formed, the workpiece is compressed or stretched at the bent portion, and the thickness of the workpiece is likely to be uneven.

In the twist axle in the twist axle suspension device of Patent Document 2, a workpiece is stretched at an inclined portion that transitions from the left and right end sections to a straight center section. For this reason, the thickness of the workpiece tends to be non-uniform in the inclined portion.

When a torsion beam is formed, if the workpiece is fleshed out or stretched, the torsion beam may be damaged by a load when the torsion beam type suspension is used.

To prevent the workpiece thickness from becoming excessively uneven when forming the torsion beam, while lowering or raising the position of the shear center in the central portion of the torsion beam to obtain the desired alignment characteristics. An object of the present invention is to provide a torsion beam suspension.

A trailing arm which is paired on the left and right, has a support portion for the vehicle body side member at one end side thereof, and has a wheel support portion at the other end side, and a torsion beam whose both end portions are supported by the trailing arm. The torsion beam suspension is configured such that the position of the shear center at the center portion is lower or higher than the position of the shear center at both end portions in the front view or the rear view of the vehicle. The shape of the torsion beam on the plane side solves the above problems by a torsion beam type suspension in which the entire shape from one end side to the other end side is configured as a curved surface curved like a bow. Since the entire torsion beam from one end side to the other end side is configured as a curved surface curved like a bow, it is possible to prevent the work thickness from being excessively thin or the work thickness from being excessively thick. . Therefore, when using the torsion beam type suspension, it is possible to prevent the torsion beam from being damaged due to the difference in the thickness of the workpiece.

To prevent the workpiece thickness from becoming excessively uneven when forming the torsion beam, while lowering or raising the position of the shear center in the central portion of the torsion beam to obtain the desired alignment characteristics. A possible torsion beam suspension can be provided.

It is a top view which shows one Embodiment of a torsion beam type suspension. It is a bottom view of the torsion beam type suspension of FIG. It is a rear view of the torsion beam type suspension of FIG. FIG. 2 is a right side view of the torsion beam suspension of FIG. 1. It is sectional drawing in the AA part of FIG. It is sectional drawing in CC part of FIG. It is a figure which shows each position of the cross section of the torsion beam in the BB part in FIG. 1, and the cross section of the torsion beam in the CC part in FIG.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following embodiment is merely an example of an embodiment of the present invention.

As shown in FIGS. 1 to 4, the torsion beam suspension 1 of the present embodiment includes a pair of left and right trailing arms 11, a torsion beam 12 in which both ends are fixed to the trailing arms 11, and It includes a pair of reinforcement members 13 (see FIG. 5) fixed to the bottom surface side of the trailing arm 11 and the bottom surface side of the torsion beam 12. As shown in FIG. 1, the left and right trailing arms 11 and the reinforcement member 13 are symmetrical with respect to the central portion of the torsion beam 12.

As shown in FIG. 1 and the like, the torsion beam suspension 1 of this embodiment includes a wheel support 16 on one end side of the trailing arm 11. The support portion 16 includes a member called an end plate 17 and an axle (not shown), and the axle protrudes from the central portion of the end plate 17 in the left or right direction of the vehicle. With the wheel-side shaft hole inserted through the axle, the wheel is brought into contact with the end plate 17 to support the wheel.

As shown in FIG. 1 and the like, the other end of the trailing arm 11 is provided with a mounting portion 18 for the vehicle body side member. In the torsion beam suspension 1 of the present embodiment, the attachment portion 18 for the vehicle body side member is configured by incorporating a bush (not shown) made of an elastic body such as rubber in a hollow annular member 19. The trailing arm 11 and the hollow bowl-shaped member 19 are joined by welding. When the torsion beam suspension 1 is attached to the vehicle body, a shaft on the vehicle side is inserted through the hole of the bush to support the trailing arm 11 so as to be swingable with respect to the vehicle body. When a load is input to the trailing arm 11 via the wheels, the trailing arm 11 moves with respect to the vertical direction of the vehicle together with the wheel rotatably supported on the other end centering on the vehicle-side shaft passing through the bush. To displace. In FIG. 7, the height of the shaft when the trailing arm 11 swings with respect to the vehicle body, that is, the height of the vehicle-side shaft inserted through the bush is defined as “D”. Although details will be described later, in FIG. 7, the height of the shear center (shear center line) at the left and right ends of the torsion beam 12 is “E” in FIG. 7, and the shear center (shear center line) at the center portion of the torsion beam 12. Is assumed to be “F”.

As shown in FIG. 1 and the like, the trailing arm 11 has a curved shape in which a central portion is recessed like a bow toward the center of the vehicle in a plan view or a bottom view. As shown in FIG. 5, the trailing arm 11 has a substantially circular cross section from one end to the other end, and is hollow from one end side to the other end side of the trailing arm 11. ing. The trailing arm 11 on the right side of the vehicle and the trailing arm 11 on the left side of the vehicle have symmetrical shapes. Since the trailing arm 11 is configured to be hollow, the weight of the torsion beam suspension 1 can be reduced.

As shown in FIG. 7, the torsion beam 12 includes a flat plate 121, a front plate 122 of the vehicle, a back plate 123 of the vehicle, a front plate 121 and a back plate 123, respectively. And a flange 124 protruding from the edge to the front side or the back side, and the cross section is a hat shape. The plate member 121 on the plane side of the torsion beam 12 is brought into contact with the protrusion of the trailing arm 11 so that the opening on the bottom side of the torsion beam 12 faces the bottom side of the vehicle, and the trailing arm 11 and the torsion beam 12 are welded by welding. Is fixed. As shown in FIG. 7, the cross-sectional shape of the torsion beam 12 is smaller in width at the center portion of the torsion beam 12 than at both ends. And in the center part, the board | plate material 122 of the front side is long compared with the both ends.

In the torsion beam suspension 1 of the present embodiment, as shown in FIG. 1 and the like, a damper support portion 23 is provided on the inner side of one end side of the trailing arm 11. The damper support portion 23 is a groove composed of a bottom plate material, a left plate material, and a right plate material, and this groove extends toward the back side of the vehicle. The damper support part 23 includes a total of two through-holes in the left and right plate members for supporting the shaft arranged at the end part of the damper, and the plane side is opened to receive the end part of the damper. .

In the torsion beam suspension 1 of the present embodiment, a coil spring support 25 is provided between the damper support 23 and the protrusion disposed at the center of the trailing arm 11. The support portion 25 of the coil spring is composed of a bottom plate and a wall made of a plate protruding from the plane, and extends from the inside of the trailing arm 11 toward the center of the torsion beam 12. Shaped member.

In the torsion beam suspension 1 of the present embodiment, as shown in the cross-sectional view of FIG. 6, the coil spring support portion 25 and the reinforcement member 13 are constituted by an integral member. This eliminates the complexity of joining the support portion 25 and the reinforcement member 13 by welding, and prevents a decrease in rigidity caused by dividing the member into a plurality of parts.

In the torsion beam suspension 1 according to the present embodiment, the reinforcement member 13 is fixed so as to straddle the joining portion between the trailing arm 11 and the torsion beam 12. As shown in FIGS. 2 and 5, in this embodiment, the proximal end side of the reinforcement member 13 is fixed to the bottom surface side of the trailing arm 11, and the distal end side thereof is a flat plate 121 that constitutes the torsion beam 12. It is fixed to the back of the.

As shown in FIGS. 3 and 5, in the torsion beam suspension 1 of the present embodiment, the shape of the torsion beam 12 on the plane side, in other words, the shape of the plate member 121 on the plane side is one end side in front view or rear view. The whole from the other end side to the other end side is configured as a curved surface curved like a bow. There is no straight portion on the plane side of the torsion beam 12. For this reason, the entire region from one end to the other end of the torsion beam 12 is curved like a bow toward the bottom side of the vehicle except for a contact portion 125 with respect to the trailing arm 11 described later. And it curves so that the center part of the torsion beam 12 may be closest to the bottom face side.

As described above, since the entire torsion beam 12 is curved like a bow, a part of the work is prevented from being excessively stretched or compressed when the torsion beam is formed from the work by press molding or the like. Is done. Thereby, the plate | board thickness of the torsion beam 12 becomes substantially uniform from one end side to the other end side. The torsion beam 12 is repeatedly twisted during use. Since the plate thickness of the torsion beam 12 of the present embodiment is substantially uniform from one end side to the other end side, the torsion beam 12 is less likely to be damaged such as being broken or broken.

The torsion beam 12 is formed into a shape in which the entire beam from one end side to the other end side is curved like a bow by press-molding a flat steel plate. In the case of this beam shape, the shape of the steel plate before forming can be made substantially rectangular. If the shape of the steel plate before forming is substantially rectangular, it is possible to improve the yield by suppressing the generation of the end material of the steel plate. On the other hand, when an extreme bent portion or inclined portion is provided in the torsion beam, the shape of the steel plate before forming cannot be made substantially rectangular. In such a case, a large amount of the end material of the steel plate is generated, and the yield decreases.

In the torsion beam suspension 1 of the present embodiment, as shown in FIG. 7, the shear center (F) in the central portion of the torsion beam 12 is higher than the height of the shear center (E) at the left and right ends of the torsion beam 12. The height is low. The height of the shear center (E) at the left and right ends and the height of the shear center (F) at the central portion (fixed point) are higher than the axis (D) of the bush. This makes it easier to change the toe angle on the turning outer wheel side in the toe-out direction compared to the case where the center of shear (F) is not lowered with respect to the center of shear (E) at the left and right ends, and oversteer The tendency is relatively high to achieve good steering characteristics.

In the torsion beam suspension 1 of the present embodiment, the abutting portion 125 with respect to the trailing arm 11 is not configured to be bent in a bow together with the torsion beam 12. However, the abutting portion 125 may be curved with the torsion beam 12 in a bow according to the depth to which the torsion beam 12 is curved.

The contact portion 125 is a projecting piece having a shape that follows the outer shape of the trailing arm 11. By disposing the contact portions 125 at both ends of the torsion beam, the torsion beam 12 can be firmly fixed to the trailing arm 11 without rattling.

In the torsion beam suspension 1 according to the above-described embodiment, the shape of the torsion beam 12 on the plane side is curved like a bow toward the bottom side of the vehicle in the entire region from one end to the other end of the torsion beam 12 in front view or rear view. I tried to do it. By changing the form of this embodiment, the shape of the torsion beam on the plane side is curved in a bow shape toward the plane side of the vehicle in the front view or the back view from the one end to the other end. May be. In this case, the position of the shear center at the center of the torsion beam is higher than the position of the shear center at both ends of the torsion beam. This makes it easier to change the toe angle on the turning outer wheel side in the toe-in direction compared to the case where the center of shear at the center portion is not raised, and makes the understeer tendency relatively high and good steering characteristics. Can be realized.

DESCRIPTION OF SYMBOLS 1 Torsion beam type suspension 11 Trailing arm 12 Torsion beam 16 Wheel support part 18 Support part F with respect to a vehicle body side member Shear center E in a center part E Shear center in both end parts

Claims (1)

A trailing arm that is paired on the left and right, has a support portion for the vehicle body side member on one end side thereof, and has a wheel support portion on the other end side;
A torsion beam suspension having a torsion beam supported at both ends of the trailing arm,
The torsion beam is configured such that the position of the shear center at the center portion is lower or higher than the position of the shear center at both end portions in the front view or the rear view of the vehicle.
The torsion beam suspension is a torsion beam suspension in which the shape from the one end side to the other end side is curved as a bow.

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