JP4544001B2 - Torsion beam type rear suspension structure - Google Patents

Description

  The present invention relates to a torsion beam type rear suspension structure configured by connecting a pair of trailing arms with a torsion beam.

  A rear suspension of a passenger car (vehicle) includes a trailing suspension combined with a torsion beam. Many of the suspensions support the front part of a pair of trailing arms arranged on both sides in the vehicle width direction of the vehicle body so as to be able to swing on the vehicle body, and support rear wheels (wheels) on the rear part. A structure in which torsion beams extending in the vehicle width direction are connected is used, and an anti-roll effect is obtained by using the torsional rigidity of the torsion beam.

In such a rear suspension, for joining the trailing arm and the torsion beam end, generally, as disclosed in Patent Document 1, the end of the torsion beam is abutted against the side part of the trailing arm, and the abutted parts are connected to each other. Welding (butt welding) is performed.
JP 2005-8123 A

  However, the rear suspension having such a joint structure has a problem.

  One is that poor bonding is likely to occur. One is that it is difficult to ensure the accuracy in the vehicle width direction, and the other is that stress concentration occurs in the joint.

  In terms of poor bonding, the trailing arm is mainly cylindrical, but the shape and cross-sectional shape of each arm of the arm ensures rigidity according to the specifications, and shock absorbers such as springs and shock absorbers. And the arm support position and the wheel support position are changed in accordance with the vehicle body structure.

  The torsion beam butt joint butts the beam ends to match the shape of this complex trailing arm portion.

  By the way, for the butting, the shape of the torsion beam end must be formed into a shape that follows the cross-sectional shape of the trailing arm. However, this shape is quite complex. For this reason, the shape of the shaped beam end tends to include many variations. Because of this variation, it is difficult to properly align the torsion beam end with the trailing arm portion without a gap, and this causes a defective joint (welding failure). Or additional work is required.

  In addition, the butt joint has a unique structure of abutting and positioning, so there is very little margin for absorbing variations in the vehicle width direction (left and right direction) of each part and adjusting the position in the vehicle width direction (left and right direction). It is difficult to ensure the accuracy between the trailing arms (accuracy in the vehicle width direction), and it becomes difficult to join the torsion beams. Furthermore, it is difficult to ensure the accuracy of the values of each part of the suspension, such as toe and thrust angle.

  Regarding stress concentration, the stress when regulating the torsion of the vehicle body with the torsion beam is concentrated at the inflection part in the longitudinal direction of the vehicle body and in the width direction of the vehicle body. Thus, it is difficult to ensure durability.

    SUMMARY OF THE INVENTION An object of the present invention is to provide a torsion beam type rear suspension structure having a simple structure, capable of ensuring a good joined state and further ensuring high product accuracy and separating stress concentration from the joint. .

In one aspect of the present invention, in order to achieve the above object, a pair of trays are disposed on both sides in the vehicle width direction, the vehicle front side is swingably supported by the vehicle body, and the vehicle rear side is rotatably supported by the wheels. A torsion beam type rear suspension structure having a ring arm and a torsion beam extending in the vehicle width direction and connecting between the trailing arms. The torsion beam end suspension has three walls at the end of the torsion beam. An end wall in which a fitting insertion portion that is a space is formed is formed, and an inner wall surface of the three walls of the end wall has a first joint surface having a predetermined length and three wall surfaces parallel to the vehicle width direction. The trailing arm is formed on a side wall portion connected to the torsion beam, and has a projecting portion that forms a rectangular tube shape that protrudes inward in the vehicle width direction and whose outer shape can be fitted in the fitting insertion portion. The peripheral wall portion of the projecting portion has a predetermined length and forms a second joint surface having three wall surfaces parallel to the vehicle width direction, and the projecting portion is inserted into the end wall of the torsion beam end. Thus, a configuration is adopted in which the torsion beam end and the trailing arm are connected by overlapping and joining the first joining surface and the second joining surface.

  As a result, the torsion beam can be connected by superimposing joining of the joining surfaces with any shape of the trailing arm. Moreover, at the time of joining, the overlapping torsion beam ends and the trailing arm can be adjusted with respect to the vehicle width direction using a joining surface extending in a straight line as a guide.

  In the invention according to claim 2, in addition to the above object, the trailing arm includes a first member on the inner side in the vehicle width direction and a second member on the outer side in the vehicle width direction so that the second joint surface can be easily formed. A divided structure is formed by joining the members, and a configuration is adopted in which the first joining member is formed by drawing the second joining surface by drawing.

  In addition to the above object, the invention according to claim 3 further joins the edge of the torsion beam to the second member so that the junction of the torsion beam does not affect the durability or durability of the trailing arm. The structure which is not used was adopted so that the junction of the torsion beam did not overlap the junction of the trailing arm.

  According to the first aspect of the present invention, the shape alignment between the trailing arm and the end of the torsion beam can be satisfactorily performed only by a simple joining operation of the joining surfaces, regardless of the shape of the trailing arm.

  Therefore, any shape of the trailing arm can be connected to the torsion beam by simple overlapping joining. For this reason, generation | occurrence | production of a welding defect can be reduced and a favorable joining state can always be promised. Moreover, the overlapping torsion beam ends and the trailing arm can be adjusted (shifted) with respect to the vehicle width direction using a joint surface extending in a straight line as a guide during joining. Therefore, the dispersion in the vehicle width direction (left and right direction) and the accuracy between the trailing arms (accuracy in the vehicle width direction) can be secured when the torsion beam and the trailing arm are joined, and the values of each part such as the toe and thrust angle are highly accurate. The rear suspension with high product accuracy can be secured.

  In addition, the joint at the end of the torsion beam is always positioned at a point away from the stress concentration part of the trailing arm (the inflection part in the longitudinal direction of the vehicle body and the width direction of the vehicle body, where bending stress is concentrated). It is possible to avoid stress concentration on the part.

  According to the second aspect of the invention, in addition to the above effects, the second joint surface is molded together with the first member, so that it can be rationally molded. Moreover, it is easy to draw because it is drawn.

  According to the third aspect of the present invention, in addition to the above effect, the torsion beam junction does not overlap the junction between the first member and the second member of the trailing arm. Does not affect the durability.

[First Embodiment]
Hereinafter, the present invention will be described based on the first embodiment shown in FIG. 1 and FIG.

  FIG. 1 shows an entire frame 1 of a torsion beam type rear suspension structure of a passenger car (vehicle), for example, a trailing type rear suspension, and FIGS. 2 and 3 show exploded views of respective parts of the frame 1.

  In these drawings, 2 indicates a pair of trailing arms. The trailing arm 2 is a pair of left and right parts disposed on both sides in the vehicle width direction on the lower surface of the vehicle body. Each of these trailing arms 2 has an arm portion 3 extending in the longitudinal direction of the vehicle body. These arm portions 3 have a complicated shape, for example, the span on the front side of the vehicle body is narrower than the span on the rear side of the vehicle body, and the middle is inward in the vehicle width direction in order to ensure rigidity, to install shock absorbers and to set the support position. It is comprised from the cylindrical member of the shape bent by the big circular arc. Each of these arm portions 3 uses a split-type component having an irregular cross-sectional shape. A structure in which members separated in the vehicle width direction inner side and the vehicle width direction outer side are joined is used for the part. Specifically, as shown in FIG. 3, the inner member in the vehicle width direction is a sheet metal (thin plate) channel-shaped (groove-shaped) inner member 4 (the first member of the present application) whose outer side (the vehicle width direction) is open. The outer member in the vehicle width direction is a channel-shaped (groove-shaped) inner member 5 made of a deformed sheet metal (thin plate) with the inner side (vehicle width direction) open (the second member of the present application). Equivalent to the member). The arm portion 3 has the opening ends of the inner member 4 and the opening ends of the outer member 5 overlapped, and the same portion is joined, for example, welded. For example, a cylindrical support portion 6 that is swingably supported by a vehicle body (not shown) is attached to the end portion of the arm portion 3 on the vehicle body front side, and on the vehicle body rear side of the arm portion 3, A bracket 7 for installing a spring and a shock absorber (both not shown) and a bracket 9 for rotatably supporting a rear wheel 8 (wheel) are attached to form the trailing arm 2 as a whole.

  On the other hand, in FIG. 1, 10 indicates a torsion beam. The torsion beam 10 uses, for example, a member extending in the vehicle width direction, for example, a channel-shaped (grooved) part made of a sheet metal whose lower end is opened and whose both end portions are thicker than the intermediate portion. The torsion beam 10 is provided between the arm portions 3. Specifically, the torsion beam 10 is disposed between, for example, the intermediate portion 3a of the arm portion 3 (the portion between the support portion 6 and the bracket 7). The torsion beam 10 extends along the vehicle width direction. Each end (both ends) of the torsion beam 10 is joined (connected) between the intermediate portions 3a (between the trailing arms 2).

  Details of the joint structure are shown in FIG. 2 and FIGS. The joining structure will be described with reference to the same drawing. At each end of the torsion beam 10, the entire end wall (three walls) of the torsion beam 10 is axially oriented (longitudinal direction) as shown in FIGS. A linear region L1 formed in parallel with each other is formed. The straight line area L1 has a predetermined length. And the space for insertion, ie, the insertion part 10a, is formed inside this end wall (only one side is shown). A joining surface 12 (corresponding to the first joining surface of the present application) extending in parallel with the axial direction (longitudinal direction) of the torsion beam 10 is formed from the inner wall surface of the insertion portion 10a.

  As shown in FIGS. 2, 3, 6 and 7, the arm 3 is connected to the torsion beam 10 at the point of connection, specifically, the side wall of each inner member 4 forming the intermediate portion 3a. Projections 15 projecting inward (in the vehicle width direction) are formed (only one side is shown). Each of the protrusions 15 is formed by drawing to push a part of the side wall portion inward (vehicle width direction). The external shape of these protrusions 15 has a rectangular tube shape that can be fitted into the insertion portion 10a. Each of the rectangular cylindrical projecting portions 15 extends in parallel in the vehicle width direction, and the peripheral wall portion is a portion parallel to the vehicle width direction. A straight region L2 extending in parallel with the vehicle width direction is formed at this portion. This linear area L2 has a predetermined length from the tip. And the joint surface 16 (equivalent to the 2nd joint surface of this application) parallel to a vehicle width direction is formed from the surrounding wall part outer surface of this protrusion part 15. As shown in FIG.

  The torsion beam end and the trailing arm 2 are joined using these joining surfaces 12 and 16.

  That is, to explain the way of joining, when joining the torsion beam end and the trailing arm 2 as shown in FIG. 2, first, the protruding portion 15 of each trailing arm 2 is inserted into the insertion portion 10a of the torsion beam end. Fit into. As a result, as shown in FIGS. 4 and 5, the joint surface 12 (plane) of the torsion beam 10 and the joint surface 16 (plane) of the trailing arm 2 overlap each other in the vehicle longitudinal direction. The torsion beam ends can be aligned with the trailing arm 2 without any gap by simply overlapping the planes (shape alignment: good).

  At this time, the joining portion where the fitting portion 10a and the protruding portion 15 are combined is in a state in which the joining surface 12 and the joining surface 16 parallel to the vehicle width direction (the axial direction of the beam) overlap each other. The trailing arm 2 can be displaced in the vehicle width direction (axial direction of the torsion beam 10).

  For this reason, if there is a variation in the welding between the torsion beam end and the trailing arm 2, the position where the joining surfaces 12 and 16 overlap may be adjusted by shifting from this state. That is, the dispersion | variation at the time of welding is absorbed only by displacing the joining surfaces 12 and 16 along the linear areas L1 and L2. Further, when adjusting the dimension between the trailing arms 2 and 2 in order to ensure accuracy, the required distance between the trailing arms 2 and 2 can be adjusted by shifting the overlapping position of the joining surfaces 12 and 16 in the same manner. Accuracy is ensured.

  After the dimensions of each part such as the dimension in the vehicle width direction are thus defined, the torsion beam 10 and the trailing arms 2 and 2 are assembled by welding, for example, the peripheral wall of the overlapping insertion part 10a and the peripheral wall of the protruding part 15 by welding. Go up.

Therefore, when the joining structure is formed by superimposing the joining surfaces 12 and 16 parallel to the beam longitudinal direction and the vehicle width direction, the joining surface 12 of the torsion beam 10 and the trailing arm 2 are simply formed regardless of the shape of the trailing arm 2. The shape of the torsion beam end and the trailing arm 2 required can be matched only by superimposing the joining surface 16.

  Therefore, any shape of the trailing arm 2 can be connected to the torsion beam 10 in a simple and superposed manner in which the joining surfaces are reliably aligned. For this reason, generation | occurrence | production of the welding defect resulting from the defect along a shape alignment can be reduced, and a favorable joining state can always be promised.

    Moreover, the variation during welding and the accuracy between the trailing arms 2 and 2 (accuracy in the vehicle width direction) can be easily achieved by displacement (adjustment) in the vehicle width direction with the joint surfaces 12 and 16 extending linearly as guides. In addition, it can be absorbed or set with high accuracy, and the values of each part such as toe and thrust angle are determined with high accuracy. For this reason, a rear suspension having high product accuracy can be obtained.

  In addition, since the joining of the torsion beam ends is performed only within the joining surface 16 of the trailing arm 2, the joining portion of the torsion beam ends is always the high stress portion of the trailing arm 2, specifically α in FIG. Can be positioned at a point away from the bent portion (region shown by cross-hatching) between the beam end and the brackets 7 and 9, which is a portion where the bending stress tends to concentrate as shown in FIG. Stress concentration can be avoided.

  Further, the projecting portion 15 of the trailing arm 2 uses a split type (vehicle width direction) trailing arm 2, and the inner member 4 of the trailing arm 2 is molded by drawing. Therefore, the joint surface 16 can be formed together (simultaneously) using the molding process of the inner member 4, and the joint surface 16 can be reasonably formed.

  In particular, as shown in FIGS. 2, 4 and 5, the end edge portion 10 b (tip edge) of the fitting insertion portion 10 a (torsion beam end) has a structure in which the outer member 5 (joining) of the trailing arm 2 is not joined. By adopting it, the welded part (joint part) at the end of the torsion beam does not overlap with the welded part of the trailing arm 2 (part where the inner member 4 and the outer member 5 are joined). The welding (joining) of the torsion beam 10 does not affect the rigidity strength of the trailing arm 2.

  In the present embodiment, the torsion beam 10 is welded (joined) only to the inner member 4 of the trailing arm 2. However, if the torsion beam 10 is not welded (joined) to the outer member 5, as shown in FIG. Alternatively, the reinforcing member 17 may be welded (joined) to the torsion beam 10 and the inner member 4.

[Second Embodiment]
FIG. 9 shows a second embodiment of the present invention.

  In this embodiment, the trailing arm 2 is formed from a pipe member 20.

  At this time, a fitting component 21 having a rectangular protrusion 15 as described in the first embodiment is separately attached to a portion of the trailing arm 2 on the inner side in the vehicle width direction (one side). Only shown). Thus, as in the first embodiment, the protruding portion 15 of the fitting component 21 and the fitting insertion portion 10a at the end of the torsion beam are fitted, and the bonding surface 12 of the torsion beam 10 and the bonding surface 16 of the protruding portion 15 are overlapped. The end of the torsion beam and the trailing arm 2 can be joined by simple lap welding.

  Even if it does in this way, there exists an effect similar to 1st Embodiment. However, in the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention. For example, in the above-described embodiments, the torsion beam formed by a channel-shaped member having an opening at the lower part is used. However, the present invention is not limited to this, and for example, a torsion beam formed by a member having another cross-sectional shape such as each cylindrical shape is used. The structure used may be used.

The perspective view which shows the torsion beam type suspension structure of the 1st Embodiment of this invention. FIG. 3 is an exploded perspective view showing when the torsion beam end is aligned with the trailing arm in the suspension structure. The disassembled perspective view for demonstrating a division type trailing arm in the suspension structure. Sectional drawing which follows the AA line in FIG. Sectional drawing which follows the BB line in FIG. Sectional drawing which follows the CC line | wire in FIG. Sectional drawing which follows the DD line | wire in FIG. FIG. 3 is a perspective view showing the reinforcing member provided between the torsion beam and the trailing arm in the torsion beam suspension structure according to the first embodiment of the present invention. The perspective view for demonstrating the junction structure of the torsion beam end used as the principal part of the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Trailing arm, 4 ... Inner member (1st member), 5 ... Outer member (2nd member), 10 ... Torsion beam, 10a ... Insertion part, 12 ... Joining surface (1st joining surface), 15 ... Protrusion Part, 16 ... joining surface (second joining surface), 17 ... reinforcing member.

Claims (3)

A pair of trailing arms that are arranged on both sides in the vehicle width direction, the front side of the vehicle is swingably supported by the vehicle body, and the rear side of the vehicle rotatably supports the wheels;
A torsion beam type rear suspension structure comprising a torsion beam extending in the vehicle width direction and connecting between the trailing arms,
At the end of the torsion beam, there is formed an end wall having a three-sided wall and in which an insertion portion that is a space for insertion is formed.
The inner wall surfaces of the three walls of the end wall form a first joint surface having a predetermined length and three wall surfaces parallel to the vehicle width direction,
The trailing arm is formed on the side wall portion connected to the torsion beam, with a protruding portion forming a rectangular tube shape that protrudes inward in the vehicle width direction and whose outer shape can be inserted into the fitting insertion portion,
The peripheral wall portion of the protruding portion forms a second joint surface having a predetermined length and three wall surfaces parallel to the vehicle width direction,
The projecting portion is fitted into the end wall of the torsion beam end, and the first joining surface and the second joining surface are overlapped and joined, thereby connecting the torsion beam end and the trailing arm. A torsion beam type rear suspension structure. The torsion beam type rear suspension structure according to claim 1,
The trailing arm is composed of a divided structure formed by joining a first member on the inner side in the vehicle width direction and a second member on the outer side in the vehicle width direction,
The torsion beam type rear suspension structure, wherein the second joint surface is formed on the first member by drawing. The torsion beam type rear suspension structure according to claim 2,
The torsion beam type rear suspension structure is characterized in that an end edge portion of the torsion beam is not joined to the second member.

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