JP4632036B2 - Torsion beam type rear suspension - Google Patents

Description

  The present invention relates to a torsion beam type rear suspension.

The torsion beam type suspension includes a torsion beam extending in the vehicle width direction and a pair of left and right arms extending in the longitudinal direction of the vehicle body, and has a structure in which an end of the torsion beam is connected to a central portion in the longitudinal direction of the arm. The torsion beam type suspension is typically widely used in the rear suspension of small FF vehicles. In this case, generally, as disclosed in Patent Document 1, the front end of the arm is connected to the vehicle body, A trailing arm type with a wheel attached to the rear end is adopted, and a coil spring is assembled. In order to mount this coil spring, a spring seat is disposed at a corner portion between the trailing arm and the torsion beam. This spring seat is generally fixed to a trailing arm (Patent Document 2).
No. 2001-321846 No. 2004-34866

  The running performance of the vehicle is greatly influenced by the so-called undercarriage rigidity. Therefore, in order to increase the rigidity of the suspension with the torsion beam type suspension, it is necessary to increase the rigidity of the spring seat and the trailing arm that supports the spring seat, but there is a limit. Further, when the rigidity of the spring seat and the trailing arm is inadvertently increased, the balance of the torsion beam type suspension including the torsion beam and the pair of left and right trailing arms may be lost.

  On the other hand, in order to increase the support rigidity of the spring seat, it can be considered that the spring seat is also carried by the torsion beam together with the trailing arm. However, in the torsion beam suspension, the torsion beam is responsible for the main suspension function, so fixing the spring seat to the torsion beam hinders the function of the torsion beam, that is, the torsional characteristics of the torsion beam longitudinal end, and the suspension performance of the torsion beam is reduced. There is a risk of damage.

  An object of the present invention is to provide a torsion beam type rear suspension that can reduce the suspension of the suspension performance of the torsion beam locally when the spring seat is carried not only by the trailing arm but also by the torsion beam. It is in.

According to the present invention, such a technical problem is
A pair of left and right trailing arms (2) extending in the longitudinal direction of the vehicle body, supported at the front end so as to be swingable on the vehicle body, and rotatably supporting the rear wheel via a bracket (5) on the rear end;
A torsion beam (3) having an irregular cross-sectional shape, extending in the vehicle width direction, each longitudinal end of which is connected to the longitudinal center portion of the trailing arm (2);
A spring seat disposed at a corner portion between the longitudinal end portion of the torsion beam (3) and the rear portion of the trailing arm (2) and fixed to the torsion beam (3) and the trailing arm (2). (6)
The torsion beam (3) has an enlarged portion that is expanded outward in the vehicle width direction so that the longitudinal end thereof is positioned outward in the vehicle width direction as compared to the front end when viewed in plan. a (E), the amount overlaps with the the torsion beam (3) and the trailing arm (2) is to increase towards the rear than the front end in the longitudinal direction end portion of the torsion beam (3) Has an enlarged part (E),
A mounting seat for the coil spring (8) formed on the spring seat (6) is provided at a rear portion in the vehicle longitudinal direction of the spring seat (6), and the mounting seat for the coil spring (8) is mounted in the vehicle longitudinal direction. Is overlapped with the bracket (5), and is formed at a position closer to the bracket (5) in the vehicle longitudinal direction than the torsion beam (3),
The spring seat (6) is fixed to the torsion beam (3) with respect to a rear portion of the torsion beam (3).
The spring seat (6) is formed with a vertical flange (13) extending in the vertical direction at a portion on the inner side in the vehicle width direction among the portions facing the torsion beam (3), and the vertical flange (13) The front end edge is fixed to the torsion beam (3), and the vertical flange (13) extends in the vehicle longitudinal direction along the vehicle width direction inner edge of the bottom wall of the spring seat (6), and the front end edge thereof Has a first flange portion (14) fixed to the torsion beam (3), and a second flange portion (15) extending in the vehicle width direction along the rear edge of the bottom wall,
The second flange portion (15) extends from the rear portion of the mounting seat of the coil spring (8) so as to incline outward and in the vehicle width direction, and extends from the mounting seat of the coil spring (8) in the vehicle longitudinal direction. A damper mounting bracket (5) protruding rearward is welded to the rear surface of the vehicle body of the second flange portion (15) at the rear and in the vehicle width direction outside.
The damper mounting bracket (5) is more planar than the bracket (5) in order to support the lower end of a tubular damper extending in the vertical direction at a position spaced inward in the vehicle width direction from the bracket (5) in plan view. The rear end of the damper mounting bracket (5) protrudes rearward and the inner end in the vehicle width direction of the coil spring (8) is disposed on the inner side in the vehicle width direction of the outer end in the vehicle width direction. This is achieved by providing a torsion beam type rear suspension.

  That is, according to the present invention, the portion where the spring seat is disposed is the longitudinal end portion of the torsion beam, the enlarged portion is provided at the longitudinal direction end portion of the torsion beam, and the shape of the enlarged portion is formed at the rear end of the torsion beam. Because the shape is located on the outer side in the vehicle width direction compared to the front end, and the amount of overlap of the torsion beam and the trailing arm by this enlarged part is set so that the rear end of the torsion beam is larger, The rigidity of the end of the torsion beam is greater at the rear end than at the front end.

  In this way, the rigidity at the longitudinal end of the torsion beam is made different between the front part and the rear part of the torsion beam, and the rear part is provided with relatively higher rigidity. When the spring seat is carried by the torsion beam, the load applied to the torsion beam from the spring seat by the reaction force of the coil spring acts to twist the rear part of the torsion beam downward, but for the load from this spring seat, A relatively high rigidity is given to the rear part of the torsion beam, so that the spring seat is also carried by the torsion beam by balancing the action of twisting the rear part of the torsion beam downward and the rigidity of the torsion beam. It can suppress that performance is partially inhibited.

In a preferred embodiment of the present invention, the spring seat is fixed to the torsion beam with respect to the rear portion of the torsion beam. Further, in a preferred embodiment of the present invention, the spring seat is formed with a vertical flange extending in the vertical direction at a portion on the inner side in the vehicle width direction among the portions facing the torsion beam, and the vertical flange is fixed to the torsion beam. In addition, a portion on the trailing arm side of the vertical flange and facing the torsion beam is not fixed to the torsion beam. Thus, since the spring seat is fixed to the torsion beam with the vertical flange extending vertically, it is possible to alleviate the occurrence of stress concentration at the longitudinal end of the torsion beam. In other words, when all the region of the front end edge extending in the vehicle width direction of the spring seat is fixed to the torsion beam, there is a possibility that stress may concentrate on the boundary between the longitudinal direction end portion and the central portion of the torsion beam, which is preferable. In the embodiment, the front end edge extending in the vehicle width direction of the spring seat is not fixed to the torsion beam, and only the front end edge of the vertical flange extending in the vertical direction is fixed to the torsion beam. It is possible to alleviate stress concentration at the boundary between the direction end and the center.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic plan view of a right end portion of a torsion beam suspension applied to a rear wheel of a vehicle. The torsion beam type rear suspension 1 has a pair of left and right trailing arms 2 extending in the longitudinal direction of the vehicle body and a torsion beam 3 extending in the vehicle width direction. Each end of the trailing arm 2 is attached to the longitudinal central portion 2a of the torsion beam 3. A pair of trailing arms 2 are connected to both ends of the torsion beam 3 by welding.

  Similar to the structure disclosed in Patent Document 1 (2001-321846), the torsion beam 3 has a closed cross section and a deformed cross section formed by pressing a hollow pipe. The shape of the odd-shaped cross section is, for example, a U shape that is open downward. At the longitudinal end portion of the torsion beam 3, the U-shaped cross section has a wide opening. , The opening of the U-shaped end face is narrowed. That is, the torsion beam 3 has a shape that gradually widens from the central portion in the longitudinal direction toward the end when viewed in plan, and the longitudinal end edge of the torsion beam 3 extends toward the rear of the vehicle body. It is inclined so as to be located outside the direction. That is, an enlarged portion E having a substantially right triangle shape is formed at the end of the torsion beam 3 so that the rear end is positioned outward in the vehicle width direction as compared with the front end when viewed in plan. The enlarged portion E is designed so that the longitudinal end of the torsion beam 3 overlaps with the trailing arm 2 at the rear end compared to the front end. That is, the longitudinal end portion of the torsion beam 3 is given higher rigidity at the rear end than at the front end.

  The trailing arm 2 extending in the front-rear direction of the vehicle body has an eye 4 at the front end thereof, and the eye 4 is swingably supported by the vehicle body via a bush (not shown). The trailing arm 2 further has a bracket 5 at the rear end thereof, and a wheel (not shown) is rotatably supported via the bracket 5.

  As can be understood from FIG. 1, the trailing arm 2 has a curved shape that is concave outward in the vehicle width direction in a plan view. That is, when the trailing arm 2 is viewed in plan, the front portion 2b from the eye 4 to the front end of the central portion 2a extends obliquely inward in the vehicle width direction from the eye 4 toward the central portion 2a. The central portion 2a extends slightly inward in the vehicle width direction from the front end to the rear end, and the rear portion 2c from the rear end of the central portion 2a to the bracket 5 extends from the central portion 2a to the bracket 5. It has a shape extending greatly inclined outward in the vehicle width direction. FIG. 2 is a view of the torsion beam type suspension 1 as seen from the rear. As can be seen from FIG. 2, the trailing arm 2 has a shape extending obliquely upward from the central portion 2 a toward the bracket 5. ing.

  In the torsion beam type rear suspension 1, a spring seat 6 is disposed at a corner portion between the rear portion 2 c of the trailing arm 2 and each longitudinal end portion of the torsion beam 3.

  The spring seat 6 is formed by press forming a steel plate, and the spring seat 6 has a bottom wall 7. The torsion beam type rear suspension 1 includes a coil spring 8, and a mounting seat for the coil spring 8 is provided at the rear portion of the main bottom wall portion 7 a of the bottom wall 7 extending almost horizontally.

  The bottom wall 7 has an inclined portion 7 b that is partitioned from the main bottom wall portion 7 a by a bend line, that is, a bead 9, and the inclined portion 7 b is positioned to face the rear end portion of the trailing arm 2. That is, the bending line (bead) 9 extends straight in the longitudinal direction of the vehicle body, and the front end of the bending line 9 joins at the middle portion in the longitudinal direction of the rear portion 2 c of the trailing arm 2. An inclined portion 7 b of the spring seat 6 extends obliquely upward from the bead 9 outward in the vehicle width direction, and an outer end edge in the vehicle width direction is in contact with the trailing arm 2.

  As described above, the mounting seat of the coil spring 8 is provided at the rear portion of the bottom wall 7 of the spring seat 6, and the rear portion of the bottom wall 7 includes an inclined portion 7 b fixed to the trailing arm 2 and The bead 9 substantially increases the rigidity. Therefore, the rigidity of supporting the spring seat 6 with respect to the coil spring 8 can be ensured without preparing another reinforcing member.

  The spring seat 6 has no flange on the outer edge in the vehicle width direction, and the outer edge in the vehicle width direction is welded to the trailing arm 2 in almost the entire region. That is, the outer edge 10 in the vehicle width direction of the bottom wall 7 including the inclined portion 7b of the spring seat 6 has a shape along the side surface of the rear portion 2c of the trailing arm 2, and the outer edge 10 of the spring seat 6 is It is welded to the trailing arm 2 over the entire area. Since the outer edge in the vehicle width direction in which the spring seat 6 is welded to the trailing arm 2 has no flange, the spring seat 6 moves to the trailing arm 2 as the spring seat 6 is welded to the trailing arm 2. Can be reduced.

  The spring seat 6 has a vertical flange 13 extending across the rear edge 11 and the vehicle width direction inner edge 12. That is, the vertical flange 13 extends in the vehicle width direction along the first flange portion 14 extending in the front-rear direction along the inner edge of the bottom wall 7 and the rear edge 11 of the main bottom wall portion 7a and the inclined portion 7b. The first and second flange portions 14 and 15 are continuous and formed by bending the spring seat 6 upward. As described above, since the periphery of the mounting seat of the coil spring 8 has a three-dimensional structure with the inclined portion 7b across the first and second flange portions 14 and 15 and the bead 9, the spring seat 6 itself It is easy to ensure rigidity that can support the reaction force of the coil spring 8.

  The first flange portion 14 extending in the longitudinal direction of the vehicle body has a relatively small height dimension, while the second flange portion 15 positioned at the rear end portion of the spring seat 6 and extending in the vehicle width direction has a height dimension thereof. Is set relatively large. That is, the spring seat 6 is designed so that the rigidity adjacent to the torsion beam 3, that is, the front part is relatively low, while the rigidity adjacent to the coil spring 8, that is, the rear part is relatively high. ing.

  The first flange portion 14 extending in the longitudinal direction of the vehicle body along the inner edge of the bottom wall 7 has a relatively low height, and is adjacent to the front end portion 14 a of the first flange portion 14, that is, the torsion beam 3. The portion extends upward and forward, and has a shape in which a front end edge thereof is in contact with the torsion beam 3. That is, the front end portion 14 a of the first flange 14 has a shape in which the upper edge is enlarged upward, and the front end edge has a curved shape cut out along the rear side surface of the torsion beam 3. The front end edge of the first flange 14 is fixed to the torsion beam 3 by welding the upper part thereof, that is, the part X surrounded by an ellipse in FIGS. 2 and 3, and the lower part is not fixed to the torsion beam 3.

  As described above, a mounting seat for the coil spring 8 is provided at the rear portion of the spring seat 6, the bead 9, the inclined portion 7b, the first flange portion 14 extending in the longitudinal direction of the vehicle body, and the first extending in the vehicle width direction. The two-flange portion 15 has a three-dimensional structure to increase the rigidity around the mounting seat. In addition, the height of the second flange portion 15 is set larger than that of the first flange portion 14 and the Since the outer end of the two flange portion 15 in the vehicle width direction is fixed to the trailing arm 2, the reaction force of the coil spring 8 can be supported by the rear portion of the spring seat 6. In other words, since the front part of the spring seat 6 is designed to have a relatively low rigidity, the spring seat 6 is prevented from applying an excessive twisting force to the torsion beam 3 due to the reaction force of the coil spring 8. can do. In addition, this effect can be further ensured by providing an opening 20 extending in the vehicle width direction at the front portion of the spring seat 6 to promote deformation.

  The upper end of the front edge of the first flange 14 is welded to the torsion beam 3, and the upper part welded to the torsion beam 3 extends obliquely outward in the vehicle width direction toward the front, and this extension The direction L1 is preferably substantially parallel to the axis L2 of the eye 4 of the trailing arm 2, that is, the imaginary line L3 orthogonal to the swing axis of the trailing arm 2. Moreover, it is preferable that the front end edge of the first flange 14 has a shape in which the upper part rides on the upper surface of the torsion beam 3. According to this, since the spring seat 6 is fixed in a state of being hooked on the torsion beam 3, the support of the spring seat 6 by the torsion beam 3 can be ensured.

  The front end edge of the main bottom wall portion 7a of the spring seat 6 has no flange, and extends in the vehicle width direction along the longitudinal end of the trailing arm 2. The front end edge 15 of the main bottom wall portion 7a is preferably located at a slight distance from the trailing arm 2. In this embodiment, the trailing edge 15 is located between the spring seat 6 and the trailing arm 2. An elongated gap 17 extending along the arm 2 is formed.

  The vertical flange 13 formed along the inner edge and the rear edge of the spring seat 6 will be further described. The vertical flange 13 is a second flange portion 15 that is continuous with the first flange portion 14 having a relatively small height. Has a relatively large height dimension. The outer end edge in the vehicle width direction of the second flange portion 15 is positioned to face the side surface of the trailing arm 2 and is formed in a curved shape along the side surface of the trailing arm 2. That is, the outer edge in the vehicle width direction of the second flange portion 15 has no flange, and the outer edge in the vehicle width direction of the second flange portion 15 is welded to the trailing arm 2.

  In the drawing, reference numeral 18 denotes a damper mounting bracket, and the damper mounting bracket 18 is welded to the rear surface of the second flange 17 on the vehicle body. A tube type damper 19 is attached to the damper mounting bracket 18.

  The torsion beam type rear suspension 1 is preferably provided with an opening 20 as a means for reducing rigidity at the front end portion of the spring seat 6, that is, the front end portion of the main bottom wall portion 7a. It is preferable to extend in the vehicle width direction substantially parallel to the longitudinal direction of the torsion beam 3.

  It goes without saying that the torsion beam type suspension preferably functions effectively from one end to the other end of the torsion beam 3. In the rear suspension 1 of the embodiment, a vertical flange 13 formed by bending the spring seat 6 is used, and the front end edge extending in the vertical direction of the vertical flange 13 is fixed to the torsion beam 3 by welding. Therefore, adverse effects on the torsional deformation of the torsion beam 3 can be reduced. Of course, since the spring seat 6 is carried not only by the trailing arm 2 but also by the torsion beam 3, the support rigidity of the spring seat 6 can be increased without designing the rigidity of the trailing arm 2 and the spring seat 6 to be high. Can be improved.

  In other words, when the front edge of the spring seat 6, that is, the main bottom wall portion 7 a is fixed to the torsion beam 3, the movement of the longitudinal end of the torsion beam 3 is hindered by the spring seat 6, and the longitudinal end of the torsion beam 3 Since the suspension function is not substantially exhibited, not only the original function of the torsion beam suspension 1 including the pair of trailing arms 2 and the torsion beam 3 is impaired, but also the portion where the spring seat 6 of the torsion beam 3 is fixed. There is a risk that stress concentration occurs at the boundary with the inner portion in the vehicle width direction. On the other hand, in the embodiment, since the front end edge of the main bottom wall portion 7a of the spring seat 6 is not fixed to the torsion beam 3, the stress concentration can be reduced.

  Further, the load applied from the spring seat 6 to the torsion beam 3 due to the reaction force of the coil spring 8 tends to act to twist the rear part of the torsion beam 3 downward. The rigidity of the torsion beam 3 is made different between the front part and the rear part of the torsion beam 3, and the rear part is provided with a relatively higher rigidity to balance the influence of the load from the spring seat 6, thereby partially improving the suspension performance of the torsion beam 3. The suspension performance of the torsion beam 3 can be reduced from being obstructed by the spring seat 6.

FIG. 3 is a schematic plan view showing only a right side portion of a torsion beam type rear suspension. FIG. 2 is a rear view of the torsion beam type rear suspension of FIG. 1. FIG. 2 is a view of the torsion beam type rear suspension of FIG. 1 as viewed from the inside in the vehicle width direction to the outside. FIG. 2 is a perspective view of the torsion beam type rear suspension of FIG. 1 viewed from the inside in the vehicle width direction to the outside.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Torsion beam type rear suspension 2 Trailing arm 2a Central part of trailing arm 2b Front part of trailing arm 2c Rear part of trailing arm 3 Torsion beam 6 Spring seat 8 Coil spring 13 Vertical flange 14 First flange part 15 of vertical flange 15 Second flange part of the vertical flange E Expanded part of the torsion beam

Claims (3)

A pair of left and right trailing arms that extend in the longitudinal direction of the vehicle body, the front end is supported to be swingable by the vehicle body, and the rear wheel is rotatably supported at the rear end via a bracket;
A torsion beam having an irregular cross-sectional shape, extending in the vehicle width direction, and each longitudinal end of which is connected to a central portion in the front-rear direction of the trailing arm;
A spring seat disposed at a corner portion between a longitudinal end portion of the torsion beam and a rear portion of the trailing arm and fixed to the torsion beam and the trailing arm;
The torsion beam is an enlarged portion that expands outward in the vehicle width direction so that the longitudinal end thereof is positioned outward in the vehicle width direction as compared to the front end when viewed in a plan view. The amount of overlap between the torsion beam and the trailing arm has an enlarged portion that increases the rear end compared to the front end at the longitudinal end of the torsion beam,
A coil spring mounting seat formed on the spring seat is provided at a rear portion in the vehicle longitudinal direction of the spring seat, the coil spring mounting seat overlaps the bracket in the vehicle longitudinal direction, and the torsion beam Formed in a position closer to the bracket in the vehicle longitudinal direction than
The spring seat is fixed to the torsion beam with respect to a rear portion of the torsion beam,
In the spring seat, a vertical flange extending in the vertical direction is formed at a portion on the inner side in the vehicle width direction of the portion facing the torsion beam, and a front end edge of the vertical flange is fixed to the torsion beam. The vertical flange extends in the longitudinal direction of the vehicle body along the inner edge in the vehicle width direction of the bottom wall of the spring seat, and has a first flange portion whose front end edge is fixed to the torsion beam, and a rear edge of the bottom wall. And a second flange portion extending in the vehicle width direction.
The second flange portion extends from the rear portion of the mounting seat of the coil spring so as to incline toward the outside in the vehicle width direction and forward, and the second flange portion extends rearward in the vehicle body front-rear direction and outside in the vehicle width direction from the mounting seat of the coil spring. A damper mounting bracket that protrudes rearward is welded to the rear surface of the vehicle body of the 2 flange portion,
The damper mounting bracket projects rearward from the bracket and supports the lower end of a tubular damper extending in the vertical direction in a plan view in a position spaced from the bracket inward in the vehicle width direction, and the damper mounting bracket. The torsion beam type rear suspension is arranged such that an inner end in the vehicle width direction of the coil spring is located on an inner side in the vehicle width direction with respect to an outer end in the vehicle width direction of the coil spring. The front edge of the vertical flange is fixed to said torsion beam, claim 1 site facing the torsion beam a the trailing arm side than said longitudinal flange characterized in that it is a non-fixed to said torsion beam Torsion beam type rear suspension as described in 1. A bead is provided on the spring seat at a position on the outer side in the vehicle width direction relative to the mounting seat of the coil spring, and an outer edge in the vehicle width direction of an inclined portion gradually becoming higher from the bead toward the trailing arm. There torsion beam type rear suspension mounting serial to claim 1 or 2, characterized in that it is joined to the trailing arm.

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