JP2018058513A - Structure of torsion beam and torsion beam type suspension - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize lighter weight by efficiently improving endurance strength, static strength and rigidity performance, with no significant increase in weight of a torsion beam.SOLUTION: Relating to a structure of a torsion beam 3 which is arranged along a vehicle width direction and has an U-like cross section, with a lower side of the vehicle being opened, lower end parts 31a,32a of wall parts 31,32 on an open side of the torsion beam 3 are bent toward the outside of the beam along a back and forth direction of the vehicle, and the lower end part 32a of the wall part 32 positioned on a rear side of the vehicle, in the torsion beam 3, has a highest rigidity.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a structure of a torsion beam disposed along a vehicle width direction, and a torsion beam suspension including the torsion beam.

In conventional vehicles, a pair of left and right trailing arms are joined to the left and right end portions of the torsion beam arranged along the vehicle width direction in order to achieve vehicle weight reduction, space saving, and cost reduction. Some use a torsion beam suspension.
For the torsion beam of such a torsion beam type suspension, the relative displacement in the vehicle vertical direction generated between the left and right wheels due to the roll load at the time of turning or unevenness of the road surface is absorbed by twisting, and by the twisting reaction force Since it is necessary to regulate the torsion beam, an appropriate torsional rigidity is required.

  The conventional torsion beam has a substantially U-shaped cross-sectional shape opened at the lower side of the vehicle, and the vertical wall portions extending in the vehicle vertical direction are provided facing each other at the front and rear positions of the vehicle. Of these vertical wall portions, the thickness of one vertical wall portion is formed to be thicker overall than the other vertical wall portion, and is configured to be higher than the rigidity of the other vertical wall portion. Accordingly, at least the torsion beam in the vicinity of the intermediate portion in the vehicle width direction has a curved portion formed in a curved shape so as to protrude one rigid vertical wall portion (see, for example, Patent Document 1).

Japanese Patent No. 546576

However, in the above-described conventional torsion beam, the boundary between the vertical wall portion with high rigidity and the vertical wall portion with low rigidity becomes a step due to the difference in plate thickness, and there is a concern that stress concentrates on the step portion. On the other hand, if the rigidity of the entire vertical wall portion of the torsion beam is increased in order to remove such a concern, there is a problem that the weight of the torsion beam increases.
Further, since the plate thickness of the vertical wall portion having high rigidity is formed constant, it is difficult to adjust torsional rigidity that requires an appropriate value. Therefore, when using aluminum members with lower strength than steel plates and applying them to torsion beams of light vehicles and small vehicles with low required torsional rigidity, the plate thickness is increased to ensure the same strength as steel plates. As a result, the torsional rigidity may become too high.

  The present invention has been made in view of such circumstances, and its purpose is to efficiently improve durability strength, static strength, and rigidity performance without significantly increasing the weight of the torsion beam, and to reduce weight. A torsion beam structure and a torsion beam suspension capable of realizing the above are provided.

  In order to solve the above-described problems of the prior art, the present invention provides a torsion beam structure having a substantially U-shaped cross section that is arranged along the vehicle width direction and that opens on the vehicle lower side, and has a lower end on the opening side of the torsion beam. Is bent toward the vehicle outer side in the vehicle front-rear direction, and the lower end portion of the torsion beam located on the vehicle rear side has the highest rigidity.

  In another aspect of the present invention, a torsion beam having a substantially U-shaped cross section that is disposed along the vehicle width direction and that opens at the vehicle lower side is joined to a trailing arm that is disposed on both right and left sides in the vehicle width direction. In the torsion beam suspension, the lower end portion on the opening side of the torsion beam is bent toward the vehicle outer side in the vehicle front-rear direction, and the lower end portion located on the vehicle rear side of the torsion beam has the highest rigidity. The torsion beam and the trailing arm have a joint to which a part of the torsion beam and the trailing arm is joined, and the joint located on the vehicle front side of the trailing arm is on the vehicle rear side. It has rigidity higher than the said junction part located in.

  As described above, the structure of the torsion beam according to the present invention is a torsion beam that is disposed along the vehicle width direction and has a substantially U-shaped cross section that is open at the vehicle lower side. Since the lower end portion of the torsion beam located on the rear side of the vehicle has the highest rigidity, it is the first when a large force is applied from the tire to the torsion beam. It is possible to improve the static strength of the wall portion on the vehicle rear side that undergoes plastic deformation. In addition, since there is no step due to the difference in plate thickness on the wall of the torsion beam, it is possible to eliminate stress concentration on the torsion beam, and torsional rigidity can be adjusted by changing the plate thickness. It can be done easily.

Further, another torsion beam type suspension according to the present invention includes a torsion beam disposed along the vehicle width direction and having a substantially U-shaped cross-section with an opening at the vehicle lower side, and a trailing ring disposed on both left and right sides in the vehicle width direction. The lower end portion on the opening side of the torsion beam is bent toward the vehicle outer side in the vehicle front-rear direction, and the lower end portion located on the vehicle rear side of the torsion beam is the most. The joint having a high rigidity, the torsion beam and the trailing arm having a joint to which a part of the torsion beam and the trailing arm is joined, and located on the vehicle front side of the trailing arm Has higher rigidity than the joint located on the vehicle rear side. Therefore, in the torsion beam suspension according to the present invention, the rigidity difference between the vehicle front side and the vehicle rear side can be reduced while increasing the rigidity on the vehicle front side at the junction between the torsion beam and the trailing arm. Therefore, according to the torsion beam suspension of the present invention, when the suspension is bent in the vertical direction of the vehicle, it is possible to suppress deformation of the wall portion on the vehicle front side in the vicinity of the joint portion so as to bulge outward and open. Generation of stress can be suppressed.
The reason for this configuration is that in the torsion beam suspension, the spring mounting portion and the absorber mounting portion are provided at the location of the trailing arm on the rear side of the vehicle relative to the torsion beam. It is higher than the rigidity on the front side. In addition, the torsion beam of the present invention has the highest rigidity at the lower end portion on the vehicle rear side, so that the rigidity on the vehicle rear side is high. Therefore, when the torsion beam suspension is bent in the vertical direction of the vehicle, in the vicinity of the joint portion, the wall portion on the vehicle front side with low rigidity is deformed so as to bulge outward and a high stress is generated. This is because there is a need to suppress the generation of such stress.

It is a disassembled perspective view which shows the torsion beam type suspension which concerns on embodiment of this invention. It is an enlarged view of the Z section in FIG. 1, and is a perspective view for explaining an input load to the torsion beam. It is the perspective view seen from the state in the state before joining the torsion beam and the trailing arm of the torsion beam type suspension concerning the embodiment of the present invention. It is the perspective view seen from the upper part in the state which joined the torsion beam and the trailing arm of the torsion beam type suspension concerning the embodiment of the present invention. It is the sectional view on the AA line in FIG. It is the BB sectional view taken on the line in FIG.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.
1 to 6 show a torsion beam structure and a torsion beam suspension according to an embodiment of the present invention. In the figure, the arrow Fr indicates the front of the vehicle, the arrow O indicates the vehicle outer direction, and the arrow U indicates the vehicle upper direction. In FIG. 2, the arrow F1 indicates the vertical force (vertical load) of the tire contact point G, the arrow F2 indicates the longitudinal force (front / rear load) of the tire contact point G, and the arrow F3 indicates the lateral force (lateral load) of the tire contact point G. Each direction is shown.

  As shown in FIGS. 1 and 2, the torsion beam suspension 1 according to the embodiment of the present invention is mounted on a four-wheel type automobile or the like as a rear suspension, and the left and right wheels 2 pass through the torsion beam suspension 1. Are suspended on the vehicle body (not shown). Such a torsion beam type suspension 1 includes a long torsion beam 3 arranged along the vehicle width direction and a pair of left and right sides arranged at the left and right side portions in the vehicle width direction and respectively connected to the left and right end portions of the torsion beam 3. A trailing arm 4 is provided. A spring 5 and a shock absorber 6 are attached to the trailing arm 4 and are suspended from the vehicle body.

  As shown in FIGS. 1 to 4, the trailing arm 4 of the present embodiment is made of an aluminum die casting using a non-ferrous alloy such as a light metal alloy and has an open cross-sectional structure. A beam joint portion 4a extending in the vehicle width direction is provided at a vehicle inner side intermediate portion of the trailing arm 4 in the vehicle front-rear direction, and a front arm portion extending in the vehicle front-rear direction on the opposite side of the beam joint portion 4a. 4b and a rear arm portion 4c are provided. The trailing arm 4 is not limited to die casting but may be casting. Moreover, what press-molded the aluminum plate, aluminum extrusion material, and aluminum forging may be sufficient, and what joined using two or more types of these manufacturing methods may be sufficient. The material of the trailing arm 4 is not limited to aluminum, and may be a light metal material such as magnesium or a resin material.

  The beam joining portion 4 a of the trailing arm 4 is a joined portion with the torsion beam 3 to be abutted, and is provided with a step corresponding to the thickness of the torsion beam 3. As shown in FIG. 6, the outer peripheral shape of the cross section of the beam joint 4a is substantially the same as the inner peripheral shape of the torsion beam 3, and is formed into a substantially U-shaped vertical cross section with the vehicle lower side opened in the vehicle side view. Has been. That is, the beam joining portion 4 a of the trailing arm 4 has a vehicle front side wall portion 41, a vehicle rear side wall portion 42, and a vehicle upper portion 43. Moreover, the left and right end portions 3a of the torsion beam 3 are overlapped from above the vehicle on the tip end side located on the vehicle inner side of the beam joint portion 4a. The cross-sectional area of the beam joint portion 4a is reduced toward the vehicle center side. For this reason, in a state where the end 3a of the torsion beam 3 and the beam joint 4a of the trailing arm 4 are overlapped, the outer periphery of the torsion beam 3 and the outer periphery of the trailing arm 4 are substantially flat (flat). It is configured as follows.

  As shown in FIGS. 1 and 2, a cylindrical bush 44 as an elastic member is press-fitted into the front arm portion 4 b of the trailing arm 4, and the trailing arm 4 and the vehicle body frame ( (Not shown) is fastened with a bolt, and is configured to swing around the bolt as a central axis. Further, a hub mounting portion 45, a spring mounting portion 46, and an absorber mounting portion 47 are provided on the rear arm portion 4 c of the trailing arm 4. A hub 7 and a brake drum 8 are attached to the hub attachment portion 45, and the wheel 2 is rotatably supported. Further, the spring attachment portion 46 supports the lower end of the spring 5 whose upper end is attached to a vehicle body frame (not shown), and is arranged inside the trailing arm 4 in the vehicle width direction. And the absorber attachment part 47 is located in the vehicle rear of the spring attachment part 46, and is comprised so that a rocking | fluctuation motion may be made by using this bolt as a central axis by fastening the shock absorber 6 with a bolt. The upper end of the shock absorber 6 is supported by a vehicle body frame (not shown).

In the torsion beam suspension 1 of the present embodiment, the load input to the torsion beam 3 is applied to the tire ground contact point G in addition to the vertical force, the longitudinal force and the lateral force indicated by arrows F1, F2 and F3 in FIG. There is a roll load that applies a reverse phase displacement to the wheel 2 in the vertical direction of the vehicle. The vertical position of the torsion beam suspension 1 relative to the vehicle body is freely restricted by a bush 44 disposed on the vehicle front side of the torsion beam 3 and is determined by the spring 5 and the shock absorber 6.
The torsion beam 3 has high rigidity with respect to the lateral force, the longitudinal force, and the vertical force input to the trailing arm 4, but when the roll load is applied (when the left and right wheels 2 stroke in the opposite phase). Since the torsion beam 3 is stroked while twisting, an appropriate rigidity is required. Mainly, the rigidity of the trailing arm 4 is governed by the lateral force, the longitudinal force, and the vertical force, and the rigidity of the torsion beam 3 is governed by the rigidity of the roll load. In addition, the torsion beam 3 is required to have durability against repeated loads and static strength against large loads.

As shown in FIGS. 3 to 6, the torsion beam 3 of the present embodiment has a substantially U-shaped vertical cross section in which the vehicle lower side is opened in a vehicle side view by bending and bending a plate-like member having a predetermined thickness t. It is a long molded product having a shape. The torsion beam 3 has a thickness that is thinner than the thickness of the trailing arm 4, and the left and right ends in the vehicle width direction are respectively formed as arm joint portions 3 a that are joint portions with the trailing arm 4 to be abutted. Has been. The torsion beam 3 having the arm joint portion 3 a is formed in a substantially U-shaped vertical section corresponding to the beam joint portion 4 a of the trailing arm 4. That is, the torsion beam 3 includes a vehicle front side wall portion 31, a vehicle rear side wall portion 32, and a vehicle upper portion 33.
Such a torsion beam 3 is not limited to an extruded aluminum material, and may be made by die casting or casting. Moreover, the material of the torsion beam 3 is not limited to aluminum as in the case of the trailing arm 4, and may be a light metal material such as magnesium or a resin material.
It should be understood that the “bending” in the present invention refers to a shape that is bent outward, and does not necessarily require a bending step. That is, the shape of the member after being bent by processing such as pressing may be indicated, or the shape of the member that has been bent from the beginning by extrusion molding, die casting, or casting may be indicated.

Further, in the torsion beam 3 of the present embodiment, as shown in FIGS. 5 and 6, the lower end portions 31 a and 32 a of the wall portions 31 and 32 located on both front and rear sides on the opening side are directed toward the vehicle outer side in the vehicle front-rear direction. It is bent and formed into a flange shape. Moreover, the lower end portion 32 a of the wall portion 32 located on the vehicle rear side has the highest rigidity among the torsion beams 3.
Therefore, a thick portion 32A is provided at the lower end portion 32a of the wall portion 32 located on the vehicle rear side, and the thick portion 32A is formed with the largest thickness t in the torsion beam 3, and it has a thickness _{t 1.} Moreover, among the torsion beam 3, the thickness t ₂ of the upper carriage 33 is thinnest. The thickness t of the torsion beam 3 is, as indicated by the arrow in FIG. 5, the lower end portions 31 a of the wall portions 31, 32 positioned on the vehicle front side and the vehicle rear side from the vehicle upper portion 33 having the thinnest plate thickness t ₂ . It is formed so as to gradually increase toward 32a.

On the other hand, in the torsion beam suspension 1 of the present embodiment, among the beam joints 4 a of the trailing arm 4, the beam joint 4 a 1 of the wall 41 located on the vehicle front side of the trailing arm 4 is the trailing arm 4. It has rigidity higher than the beam joint part 4a2 of the wall part 42 located in the vehicle rear side. Therefore, in the beam joint portion 4a of the trailing arm 4, the length in the vehicle vertical direction from the vehicle upper portion 43 to the lower end portions 41a and 42a of the wall portions 41 and 42 is as shown in FIG. The length L1 in the vehicle vertical direction of the beam joint portion 4a1 of the wall portion 41 located on the vehicle front side is different from that on the rear side, and the beam joint portion 4a2 of the wall portion 42 located on the vehicle rear side. Is set to be longer than the length L2 in the vertical direction of the vehicle and the length in the vertical direction of the vehicle is increased (L1> L2).
Further, the lower end portion 31a of the wall portion 31 located on the vehicle front side of the torsion beam 3 and the lower end portion 41a of the wall portion 41 located on the vehicle front side of the trailing arm 4 are positioned at substantially the same height in the vehicle vertical direction. doing.

The structure of the torsion beam 3 according to the embodiment of the present invention configured as described above, and the operation and effect of the torsion beam suspension 1 provided with the torsion beam 3 will be described.
The structure of the torsion beam 3 according to the present embodiment is arranged along the vehicle width direction, has a substantially U-shaped cross section with an opening on the vehicle lower side, and lower end portions 31a of the wall portions 31 and 32 on the opening side of the torsion beam 3. 32a are bent toward the vehicle outer side in the vehicle front-rear direction, and the lower end portion 32a of the wall portion 32 located on the vehicle rear side of the torsion beam 3 has the highest rigidity. Specifically, the lower end 32a of the wall portion 32 located on the vehicle rear side of the torsion beam 3 and the thick portion 32A is provided, the thickness t ₁ of the thick portion 32A is the thickness of the torsion beam 3 It is formed thickest among t.
Therefore, according to the structure of the torsion beam 3 of the present embodiment, when a large force is applied to the torsion beam 3 from the tire 2, the static strength of the wall portion 32 on the rear side of the vehicle that is first plastically deformed can be efficiently improved. it can. The reason is that in the torsion beam suspension 1 including the torsion beam 3, the vehicle body fastening portion is provided on the vehicle front side of the torsion beam 3, and the tire fastening portion is provided on the vehicle rear side of the torsion beam 3. 2, the torsion beam 3 tends to bend and deform in the vehicle vertical direction and the vehicle longitudinal direction. However, the thick portion 32A provided at the lower end portion 32a of the wall portion 32 located on the vehicle rear side of the torsion beam 3 suppresses the bending deformation of the torsion beam 3 in the vehicle up-down direction and the vehicle front-rear direction. It is because it can raise.
In addition, since there are no steps due to the difference in the thickness t on the wall portions 31 and 32 on both the front and rear sides of the torsion beam 3, stress concentration due to the difference in the thickness t of the torsion beam 3 can be eliminated. The torsional rigidity due to the change of t can be easily adjusted.

  Further, the torsion beam 3 having the structure of this embodiment is formed in a flange shape by bending the lower end portions 31a, 32a of the wall portions 31, 32 located on both the front and rear sides on the opening side toward the vehicle outer side in the vehicle front-rear direction. Therefore, the cross-sectional second moment is large and the rigidity is high, so that bending deformation can be further suppressed. In addition, when joining the torsion beam 3 and the trailing arm 4, it is necessary to insert the beam joint 4 a of the trailing arm 4 into the arm joint 3 a of the torsion beam 3. Since it is provided on the vehicle outer side of the lower end portion 32a of the wall portion 32 located on the rear side of the vehicle and the thick portion 32A does not get in the way, the joining work can be easily performed, and the productivity of the torsion beam suspension 1 is achieved. Can be improved.

Further, in the structure of the torsion beam 3 of the present embodiment, among the thickness t of the torsion beam 3, since the thickness t ₂ of the upper carriage 33 is thinnest, it is possible to reduce the weight of the torsion beam 3 it can. The vehicle upper portion 33 of the torsion beam 3 is a portion having a small contribution to the static strength and roll rigidity, so that it does not matter even if it is formed thin.
Further, in the case of a collision from the rear of the vehicle, the torsion beam 3 is liable to be deformed by being crushed at the upper portion 33 of the vehicle, so that the weakly strong joint is prevented from being broken so as to be bent in the vehicle front-rear direction. It is possible to prevent the surface from coming into contact with the fuel tank located in front of the vehicle. In addition, when the torsion beam 3 and the trailing arm 4 are joined by welding when the welding start point is the vehicle upper part 33, welding is performed in two passes from the vehicle upper side to the vehicle front side and the vehicle rear side from the viewpoint of workability. It will be. At this time, since the thickness t ₂ of the vehicle upper portion 33 of the torsion beam 3 is made the smallest, the gap between the torsion beam 3 and the trailing arm 4 can be made larger than the portion other than the vehicle upper portion 33. The gas generated during welding can be easily released.

Further, the thickness t of the torsion beam 3, the thinnest thickness of t ₂ of the upper carriage 33 in the vehicle front wall 31 and the wall portion 32 of the vehicle rear-side lower end 31a, so as to increase gradually toward the 32a Since it is formed, stress concentration due to the difference in the thickness t of the torsion beam 3 can be reliably eliminated. In addition, since the thickness t of the torsion beam 3 can be freely changed, the roll rigidity (torsional rigidity) can be easily adjusted.

On the other hand, the torsion beam type suspension 1 of the present embodiment is arranged along the vehicle width direction, and the torsion beam 3 having a substantially U-shaped cross section opened at the lower side of the vehicle, and the trailing that is arranged on both the left and right sides in the vehicle width direction. The arm 4 is joined, and the lower end portions 31a and 32a of the wall portions 31 and 32 located on the opening side of the torsion beam 3 are bent toward the vehicle outer side in the vehicle front-rear direction. The lower end portion 32a of the wall portion 32 located on the vehicle rear side has the highest rigidity. Further, the torsion beam 3 and the trailing arm 4 have an arm joint portion 3a and a beam joint portion 4a that are joined to each other, and the beam joint portion 4a1 of the wall portion 41 located on the vehicle front side of the trailing arm 4 is: The wall portion 42 located on the vehicle rear side has higher rigidity than the beam joint portion 4a2. Specifically, in the beam joint portion 4a of the trailing arm 4, the length L1 in the vehicle vertical direction of the beam joint portion 4a1 of the wall portion 41 located on the vehicle front side is equal to that of the wall portion 42 located on the vehicle rear side. The beam joining portion 4a2 is formed larger than the length L2 in the vehicle vertical direction.
As a result, in the torsion beam suspension 1 of the present embodiment, the rigidity of the front side of the vehicle is increased while the rigidity at the front side of the vehicle is increased at the arm joint 3a and the beam joint 4a, which are the joints between the torsion beam 3 and the trailing arm 4. The difference in rigidity on the vehicle rear side can be reduced. As a result, according to the torsion beam suspension 1 of the present embodiment, when the suspension is bent in the vertical direction of the vehicle, the wall portions 31 and 41 on the front side of the vehicle bulge outward near the joint portions 3a and 4a. Opening deformation can be suppressed and generation of high stress can be suppressed.

In the torsion beam suspension 1 of the present embodiment, the lower end portions 31a and 41a of the vehicle front side wall portions 31 and 41 of the torsion beam 3 and the trailing arm 4 are positioned at substantially the same height in the vehicle vertical direction. Therefore, the generation of stress can be suppressed as compared with the case where the heights are not the same.
Furthermore, when the heights of the lower end portions 31a and 41a of the wall portions 31 and 41 on the front side of the vehicle are the same, the roll rigidity can be made more appropriate than when the heights are not the same, and the air resistance during vehicle travel can be reduced. It can reduce and suppress noise.

While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention.
For example, in the above-described embodiment, the torsion beam suspension 1 has a structure in which no stabilizer is attached, but may be applied to a structure in which a stabilizer is attached.

DESCRIPTION OF SYMBOLS 1 Torsion beam type suspension 2 Wheel 3 Torsion beam 3a Arm joint part 4 Trailing arm 4a Beam joint part 31 Vehicle front side wall part 31a Lower end part 32 Vehicle rear side wall part 32a Lower end part 32A Thick part 33 Vehicle upper part 41 Vehicle front side Wall 41a Lower end 42 Vehicle rear wall 42a Lower end 43 Upper part of vehicle t ₁ Thickness of thick part t ₂ Thickness of upper part of vehicle

Claims (12)

In the structure of the torsion beam that is arranged along the vehicle width direction and has a substantially U-shaped cross section with the vehicle lower side opened,
The lower end portion on the opening side of the torsion beam is bent toward the vehicle outer side in the vehicle longitudinal direction,
Among the torsion beams, the lower end portion located on the vehicle rear side has the highest rigidity.   The lower end portion of the torsion beam located on the vehicle rear side is provided with a thick portion, and the thick portion is formed to have the largest thickness among the torsion beams. The structure of the torsion beam described in 1.   The torsion beam structure according to claim 1 or 2, wherein the torsion beam has the thinnest plate thickness at the top of the vehicle.   The plate thickness of the torsion beam is formed so as to gradually increase from the upper part of the vehicle toward the lower end of the vehicle front side and the vehicle rear side. The structure of the torsion beam described in the paragraph.   The torsion beam according to any one of claims 1 to 4, wherein the torsion beam is a light alloy or resin torsion beam. In a torsion beam suspension in which a torsion beam having a substantially U-shaped cross section opened along the vehicle width direction and having a substantially U-shaped cross section opened to the left and right side parts in the vehicle width direction is joined.
The lower end portion on the opening side of the torsion beam is bent toward the vehicle outer side in the vehicle front-rear direction, and the lower end portion located on the vehicle rear side of the torsion beam has the highest rigidity,
The torsion beam and the trailing arm have a joint to which a part of the torsion beam and the trailing arm is joined;
The torsion beam suspension according to claim 1, wherein the joint portion located on the vehicle front side of the trailing arm has higher rigidity than the joint portion located on the vehicle rear side.   The length of the joint portion positioned on the vehicle front side of the trailing arm in the vehicle vertical direction is formed to be larger than the length of the joint portion positioned on the vehicle rear side in the vehicle vertical direction. The torsion beam type suspension according to claim 6.   8. The torsion beam suspension according to claim 6, wherein lower ends of the torsion beam and the trailing arm on the vehicle front side are positioned at substantially the same height in the vehicle vertical direction.   The thick part is provided in the lower end part located in the vehicle rear side of the said torsion beam, and this thick part is formed in the plate | board thickness most among the said torsion beams, It is characterized by the above-mentioned. The torsion beam suspension according to any one of? 8.   10. The torsion beam suspension according to claim 6, wherein a thickness of an upper part of the vehicle is the thinnest among the torsion beams. 11.   The plate thickness of the torsion beam is formed so as to gradually increase from the upper part of the vehicle toward the lower end of the vehicle front side and the vehicle rear side. The torsion beam type suspension described in the paragraph.   The torsion beam suspension according to any one of claims 6 to 11, wherein the torsion beam is a light alloy or resin torsion beam.

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