JP6350914B2 - Torsion beam suspension - Google Patents

Description

  The present invention relates to a torsion beam suspension including a torsion beam and a pair of trailing arms joined to respective ends of the torsion beam by welding.

In recent years, for the purpose of improving the fuel efficiency of automobiles, aluminum parts for undercarriage parts have been promoted in order to reduce the weight of the vehicle body.
A torsion beam suspension, which is an underbody part, includes a torsion beam and a pair of trailing arms joined to respective ends of the torsion beam by welding. The trailing arm is required to have high rigidity with respect to lateral force, longitudinal force, and vertical force. On the other hand, the torsion beam is required to have an appropriate rigidity in order to receive a roll load in which the left and right wheels are stroked in the opposite phase.

  Patent Document 1 discloses a torsion beam suspension in which a torsion beam is inserted into a trailing arm so as to relieve stress generated at an edge portion of the torsion beam while avoiding an increase in weight.

JP2012-140031

However, the torsion beam suspension of Patent Document 1 has the following problems.
(I) The torsion beam and the trailing arm are fixed only at one end, and positioning in the rotational direction is particularly difficult.
(Ii) The torsion beam is abutted against the end of the trailing arm. For example, when joining the torsion beam and the trailing arm from the upper side of the vehicle body, while confirming whether the abutting position is correct, Can not be joined.

  An object of the present invention is to provide a torsion beam suspension capable of easily positioning a torsion beam and a trailing arm, particularly in a rotational direction.

  In order to solve the above-mentioned problem, the present invention has curved portions bent at least at both ends in the longitudinal direction in a direction intersecting the longitudinal direction, and at both end edges of the curved portion in a direction intersecting the longitudinal direction. A torsion beam having a projecting edge, and a beam joint that is connected to the curved portions at both ends of the torsion beam, and a projecting part projecting in the same direction as the projecting edge of the torsion beam at the end of the beam joint A pair of trailing arms formed with edges, wherein the trailing arms overlap each other with the curved portion of the torsion beam and join the tip of the curved portion of the torsion beam; and the trailing A second joint in which the axial end face of the protruding edge of the torsion beam facing the axial end face of the protruding edge of the arm is abutted and joined. It lies in the fact that with the door.

According to the present invention, the following effects can be obtained.
According to the present invention, the trailing arm is overlapped with the curved portion of the torsion beam so that the distal end of the curved portion of the torsion beam is joined, and the axial end surface of the protruding edge of the trailing arm Since the second end of the torsion beam opposite to the end face in the axial direction of the protruding edge portion is abutted and joined, rotation of the torsion beam and the trailing arm can be suppressed. Since the end surfaces in the axial direction of the protruding edge portion of the torsion beam and the protruding edge portion of the trailing arm are abutted and joined, axial positioning can be achieved.

1 is a perspective view showing a vehicle to which a torsion beam suspension according to a first embodiment of the present invention is applied. It is a perspective view which shows the torsion beam type suspension attached to the wheel which concerns on the 1st Embodiment of this invention. It is a disassembled perspective view which decomposes | disassembles and shows the torsion beam type suspension attached to the wheel which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the trailing arm of the torsion beam type suspension which concerns on the 1st Embodiment of this invention. It is the top view seen from the upper part which shows the joint part of the torsion beam and trailing arm of the torsion beam type suspension which concerns on the 1st Embodiment of this invention. It is the sectional view on the AA line of FIG. FIG. 6 is a sectional view taken along line B-B in FIG. 5. It is a perspective view which shows the junction part of the joint part of the torsion beam and trailing arm of the torsion beam type suspension which concerns on the 1st Embodiment of this invention. The sectional shape of a torsion beam is shown, (a) is a substantially C-shaped sectional shape, (b) is a substantially V-shaped sectional shape, and (c) is a conceptual diagram illustrating a substantially U-shaped sectional shape. It is a conceptual perspective view which shows the joint part of the torsion beam and trailing arm of the torsion beam type suspension which concerns on the 1st Embodiment of this invention. (A) is the CC sectional view taken on the line of FIG. 10, (b) is the DD sectional view taken on the line of FIG. It is a longitudinal cross-sectional view which shows the joint part of the torsion beam and trailing arm of the torsion beam type suspension which concerns on the 2nd Embodiment of this invention. It is a conceptual diagram which shows the hole of the trailing arm on the opposite side to FIG. It is a conceptual diagram which shows the positional relationship of a torsion beam and a muffler.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 8.
FIG. 1 shows a vehicle to which a torsion beam suspension according to an embodiment of the present invention is applied, and FIGS. 2 and 3 are perspective views showing a first embodiment of the torsion beam suspension.

In FIG. 1, reference numeral 1 denotes a vehicle equipped with a torsion beam suspension 2 as a rear suspension. The vehicle 1 has left and right wheels 3 suspended on a vehicle body 4 via a torsion beam suspension 2.
As shown in FIGS. 2 and 3, the torsion beam suspension 2 includes a long torsion beam 5 provided along the vehicle width direction and a pair of trailing arms 6 connected to both ends of the torsion beam 5. A spring 7 and a shock absorber 8 are attached to the trailing arm 6 and suspended from the vehicle body 4.

  As shown in FIGS. 4 to 8, the trailing arm 6 is made of a casting using a non-ferrous alloy such as an aluminum alloy and has a closed cross-sectional shape with a hollow structure. This trailing arm 6 has a beam joint 6a extending in the vehicle width direction as a joint at one end, and a front arm 6b and a rear arm 6c extending in the front-rear direction of the vehicle body are provided at the other end of the beam joint 6a. It has been.

  The front arm 6b is provided with a bush press-fit portion 61 into which a tubular bush, which is an elastic member, is press-fitted. The bush press-fit portion 61 is attached to a bracket 9 attached to the vehicle body 4 via a fixing bolt 10 so as to be slidable. It has been. The rear arm 6c is provided with a carrier 62 toward the outside of the vehicle body, and a spring seat 63 and a shock absorber mounting portion 64 are provided at the inner corner in the vehicle width direction between the beam joint portion 6a and the rear arm 6c. ing. A hub 11 and a brake drum 12 are attached to the carrier 62, and the wheel 3 is rotatably supported. The spring seat 63 supports the lower end of the spring 7 attached to the vehicle body 4 at the upper end, and an attachment hole 63a is provided on the sheet plate surface. Further, as a countermeasure against stress concentration, a shape having a large R is formed from the carrier 62 and the bush press-fit portion 61 to the beam joint portion 6a.

The trailing arm 6 is formed in a substantially rectangular tube shape extending in the vehicle width direction, and a slope portion 66 formed with a slope on the lower surface side from the tip 65 toward the vehicle width direction outer side is a joint portion 13 with the torsion beam 5. It is provided as a beam junction 6a.
As shown in FIG. 7, the slope 66 is inclined with respect to the reference line BL, that is, in a direction away from the lower end of the torsion beam 5, assuming that a line extending in the longitudinal direction at the lower end of the torsion beam 5 is a reference line BL. It is inclined. That is, as shown in FIG. 7, the slope portion 66 is formed to be curved in an arc along the longitudinal direction of the torsion beam 5 with respect to the reference line BL.
The inclined surface portion 66 serves as a beam joint portion 6a to be the joint portion 13. The wall surface portion of the beam joint portion 6a is formed in a concave portion 67 so as to be slightly thinner, and will be described later between the inner wall surface of the torsion beam 5. A gap is formed. As shown in FIG. 6, an opening hole 68 </ b> A is formed in the slope portion 66. The joint portion 13 of the trailing arm 6 is provided on the vehicle body center side in the longitudinal direction of the torsion beam 5 on the non-opening side with respect to the opening side of the inclined portion provided with the inclined surface portion 66.
As shown in FIG. 5, a wall portion 67a, which serves as a locking portion for locking the distal end of the torsion beam 5, is inclined at a base end of the beam joining portion 6a as seen in a plan view and in a direction spreading toward the front of the vehicle body. Is provided. The trailing arm 6 is formed so as to be substantially flush with the torsion beam 5 in a state where the torsion beam 5 is assembled to the beam joint 6a. At both ends in the longitudinal direction of the torsion beam 5, the torsion beam 5 is formed obliquely in plan view so as to extend along a wall portion 67 a serving as a locking portion provided at the beam joining portion 6 a of the trailing arm 6.

The torsion beam 5 is a long, substantially U-shaped molded product in which a plate-like member is curved in a direction crossing the longitudinal direction and a concave strip 51 is formed on the lower surface along the longitudinal direction. The torsion beam 5 is made of an aluminum extruded material or an aluminum plate press-molded product. As shown in FIGS. 9 (a), 9 (b) and 9 (c), the cross section perpendicular to the axial direction of the beam is substantially C-shaped, V-shaped, U-shaped. It is formed in a letter-shaped open section. The torsion beam 5 can also be formed by forming a notch in the longitudinal direction on the lower surface of the tubular pipe.
The torsion beam 5 has protruding edge portions 53 in the direction intersecting the longitudinal direction at both end edge portions of the bending portion 52. A projecting edge 69 in the same direction as the projecting edge 53 of the torsion beam 5 is provided at the end of the trailing arm 6 where the wall 67a of the beam joint 6a is provided.

  As shown in FIG. 10 and FIG. 11, the torsion beam 5 is assembled with the beam joining portion 6a of the trailing arm 6 being overlapped and assembled on the inner surface side of the curved portions at both ends, except for the opening on the lower surface side. The entire circumference is welded. The welding portion between the torsion beam 5 and the beam joint portion 6a is welded along a wall surface 67a that serves as a locking portion in the vicinity of the wall portion 67 of the beam joint portion 6a of the trailing arm 6 and the tip edge portion 5a of the torsion beam 5. w1), and the front edge portion 65a of the beam joining portion 6a and the wall surface 5b of the concave portion 51 of the torsion beam 5 are welded (w3). The projecting edge 53 of the torsion beam 5 is opposed to the projecting edge 69 of the trailing arm 6 in the axial direction so that the end surfaces 53a and 69a are opposed to each other, and the end surfaces 53a and 69a are in contact with each other to be positioned. Yes. The projecting edge 53 of the torsion beam 5 and the projecting edge 69 of the trailing arm 6 are welded (w2) with their opposing surfaces butting each other. The trailing arm 6 is welded to the tip of the torsion beam 5, and the welding point w 1 between the tip edge 5 a of the torsion beam 5 and the wall surface 67 a of the beam joint 6 a of the trailing arm 6 is the first joint. The welded portion w2 between the protruding edge portion 53 of the torsion beam 5 and the protruding edge portion 69 of the trailing arm 6 is a second joint portion. The length L1 of the projecting edge 69 of the trailing arm 6 in the projecting direction and the length L2 of the projecting edge 53 of the torsion beam 5 in the projecting direction are substantially the same L1 = L2. Further, the thickness m1 of the protruding edge 69 of the trailing arm 6 and the thickness m2 of the protruding edge 53 of the torsion beam 5 are formed to be substantially the same m1 = m2. Furthermore, the length H1 in the height direction from the non-opening side to the opening side of the joint portion 13 of the trailing arm 6 and the length H2 in the height direction of the torsion beam 5 are set to be substantially the same H1 = H2. Yes.

Next, a load input to the torsion beam 5 and a restraining method will be described.
As shown in FIG. 2, the load input to the torsion beam 5 includes a lateral force F1, a longitudinal force F2, a vertical force F3, and a roll load that applies an opposite phase displacement in the vertical direction to the left and right tires. There is. Further, the bushing, which is an elastic member press-fitted in front of the torsion beam 5, is constrained to be free of rotation, and the vertical position of the vehicle body 4 is determined by the spring 7 and the shock absorber 8.

The operation of the first embodiment will be described.
The beam joining portion 6 a of the trailing arm 6 is overlapped so as to cover the concave portion 51 of the torsion beam 5, and the axial end surface 53 a of the protruding edge portion 53 of the torsion beam 5 is placed on the end surface 69 a of the protruding edge portion 69 of the trailing arm 6. Assemble until it hits.
The leading end of the bending portion 52 of the torsion beam 5 is abutted against the wall portion 67a at the end of the beam joining portion 6a of the trailing arm 6. As shown in FIG. 11A, a gap g <b> 1 is provided between the wall portion 67 a at the end of the beam joining portion 6 a of the trailing arm 6 and the tip of the curved portion 52 of the torsion beam 5. Further, a gap g <b> 2 is also formed between the beam joining portion 6 a of the trailing arm 6 and the wall surface of the torsion beam 5.

And the front-end edge part 5a of the torsion beam 5 and the wall surface 67a used as the latching | locking part near the wall part 67 of the beam junction part 6a of the trailing arm 6 are welded (w1). At the same time, the front edge 65a of the beam joining portion 6a and the inner wall surface 5b of the curved portion 52 of the torsion beam 5 are welded (w3). Thus, since the beam joining portion 6a of the trailing arm 6 and the curved portion 52 of the torsion beam 5 are welded at two portions, sufficient rigidity can be obtained. On the other hand, since the projecting edge 69 is provided at the lower end of the trailing edge 65a where the end edge 65a of the trailing arm 6 is terminated, the axial direction of the projecting edge 53 of the torsion beam 5 is provided. Positioning is achieved by the end surface 53a being brought into contact with the end surface 69a of the projecting edge 69 to be locked. Therefore, the axial end surface 53a of the protruding edge 53 of the torsion beam 5 is the end surface 69a of the protruding edge 69 before the tip of the curved portion 52 of the torsion beam 5 abuts against the wall 67a at the end of the beam joint 6a of the trailing arm 6. The gap g1 is formed between the tip of the curved portion 52 of the torsion beam 5 and the wall portion 67a.
Then, the end surface 69a of the protruding edge 69 of the trailing arm 6 and the end surface 53a of the protruding edge 53 of the torsion beam 5 are brought into contact with each other and welded together (w2).

  With this joining structure, since the cross-sectional area of the trailing arm 6 gradually decreases from the trailing arm 6 toward the torsion beam 5, the rigidity of the joining portion on the trailing arm 6 side is lowered. As a result, a rapid change in rigidity between the trailing arm 6 and the beam joint 6a can be suppressed, and stress concentration can be reduced. Since the vertical lengths of the trailing arm 6 and the beam joint 6a are substantially the same, changes in the rigidity of the joint can be suppressed and stress concentration can be reduced. When a vertical load is input to the torsion beam 5, the stress concentration generated in the welded portion on the front side of the vehicle and the beam joint portion 6a can be separated, which is a measure against damage.

According to the first embodiment, since the projecting edge 69 is provided at the lower end of the end edge 65a of the trailing end of the beam joint 6a of the trailing arm 6, the torsion beam is provided. Positioning is achieved by locking the axial end surface 53a of the projecting edge 53 of the No. 5 against the end surface 69a of the projecting edge 69. And since the protrusion edge part 69 of the trailing arm 6 and the protrusion edge part 53 of the torsion beam 5 are abutted and welded, it can be positioned in the axial direction.
Since the length in the protruding direction of the protruding edge portion 69 of the trailing arm 6 and the protruding edge portion 53 of the torsion beam 5 is set to be substantially the same L1 = L2, there is no step portion between the trailing arm 6 and the torsion beam 5. Stress concentration at the weld can be reduced. Positioning of the trailing arm 6 and the torsion beam 5 in the vertical direction of the vehicle body is facilitated.
Since the thickness of the protruding edge portion 69 of the trailing arm 6 and the protruding edge portion 53 of the torsion beam 5 is set to be substantially the same m1 = m2, the step portion between the trailing arm 6 and the torsion beam 5 is eliminated. Concentration can be eased.
Since the joint portion 13 of the trailing arm 6 with the torsion beam 5 is inclined with respect to the reference line BL extending in the longitudinal direction of the torsion beam 5, the joint portion can be lengthened and stress concentration can be reduced. .
Since the inclined portion of the joint portion 13 of the trailing arm 6 is provided with the non-opening side on the vehicle body center side in the longitudinal direction of the torsion beam 5 rather than the opening side of the inclined portion, a sudden change in rigidity can be suppressed. Stress concentration can be relaxed.
Since the length in the height direction from the non-opening side to the opening side of the joint portion 13 of the trailing arm 6 and the length in the height direction of the torsion beam 5 are set to be substantially the same H1 = H2, a sudden change in rigidity occurs. Can be suppressed and stress concentration can be reduced. Since the joint portion can be welded over the entire circumference, the boundary between the welded portion and the unwelded portion does not occur, so stress concentration can be reduced.

Since the gap g2 is provided between the trailing arm 6 and the torsion beam 5 in the vicinity of the first joint portion, gas generated during welding is easily escaped, thereby suppressing the occurrence of poor welding. it can. Occurrence of abnormal noise can be prevented even when the load is deformed and deformed.
Since a gap g1 is provided between the wall portion 67a serving as a locking portion of the trailing arm 6 in the first joint portion and the end surface 5a of the torsion beam 5, gas generated during welding is easily escaped. Thus, the occurrence of poor welding can be suppressed.
Since the entire circumference of the wall portion 67a serving as the locking portion of the trailing arm 6 and the end surface 5a of the torsion beam 5 in the first joint is welded, there is no boundary between the welded portion and the unwelded portion. , Stress concentration can be relaxed.
Since the periphery of the tip edge of the joint of the trailing arm 6 and the inner wall surface of the torsion beam 5 are welded, not only the end surface 5a of the torsion beam 5 but also the tip of the trailing arm 6 can be joined. A fitting can be provided.

By reducing the change in rigidity of the joining portion w3 on the trailing arm 6 end side between the torsion beam 5 and the beam joining portion 6a of the trailing arm 6, the stress concentration at the joining portion can be reduced.
Further, the stress concentration at the joint portion can be alleviated by joining the joint portion w1 of the torsion beam 5 and the beam joint portion 6a of the trailing arm 6 on the end portion side of the torsion beam 5 at a highly rigid position.
Furthermore, since the welding direction between the torsion beam 5 and the beam joining portion 6a of the trailing arm 6 can be two directions, that is, an oblique direction and a vertical direction, the load in the peeling direction where the joint strength is weak is suppressed, and the joint strength is reduced. Can be high.
Since the joint portions w1, w2, and w3 between the torsion beam 5 and the beam joint portion 6a of the trailing arm 6 can be welded all around, the boundary between the welded portion and the unwelded portion does not occur, and stress concentration can be suppressed.
The joint portions w1 and w2 between the torsion beam 5 and the beam joint portion 6a of the trailing arm 6 have no step on the outer surface in the radial direction of the torsion beam 5, so that stress concentration can be reduced.
Since the trailing arm 6 has a hollow cross section, a core is required at the time of casting. By installing a hole on the trailing arm 6 side between the torsion beam 5 and the beam joining portion 6a of the trailing arm 6, the carrier portion The core can be stably supported at the two holes.
By making the cross section of the torsion beam 5 an open cross section, it is possible to cope with a vehicle type that does not require much torsional rigidity.

FIGS. 12 and 13 show a second embodiment of the present invention, in which the same parts as those in FIG. 7 are denoted by the same reference numerals, and a torsion beam and a trailing arm joint of a torsion beam suspension are shown.
In this embodiment, an opening hole 68 </ b> B is formed in the wall portion 67 on the upper surface side of the beam joining portion 6 a of the trailing arm 6.
Through this opening hole 68B, gas can be released even at the end of welding in all-around welding, and the quality of the welded portion is improved. Since the area of the beam joint portion 6a of the trailing arm 6 to which the torsion beam 5 is fitted is reduced, the torsion beam 5 can be reduced in weight, and the possibility that the trailing arm 6 and the torsion beam 5 come into contact with each other when the torsion beam 5 is deformed. Therefore, it is possible to suppress the generation of abnormal noise due to contact. The rigidity of the fitting portion can be adjusted by the size and shape of the opening hole 68B, and a sudden change in rigidity can be suppressed. By joining the trailing arm 6 and the torsion beam 5 using the opening hole 68B, the joint can be reinforced. Since both surfaces of the torsion beam 5 are in contact with the outside air, the heat dissipation is improved, and the thermal influence of the muffler 14 disposed in the vicinity can be suppressed as shown in FIG.

  In addition, this invention is not limited only to the said embodiment, Joining of the trailing arm 6 and the torsion beam 5 is not welding, but uses FSW (friction stir welding), The material strength of a welded part A good joint with low drop can be obtained. In addition, it goes without saying that the present invention can be implemented with appropriate modifications within a range that does not change the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Torsion beam type suspension 3 Wheel 4 Car body 5 Torsion beam 6 Trailing arm 7 Spring 8 Shock absorber 13 Joint part 6a Beam joint part 51 Concave part 52 Curved part 53, 69 Projection edge part 53a, 69a End face 65 Tip 66 Slope part 67 Recess 67a Wall 68A, 68B, Opening hole

Claims (11)

A torsion beam having curved portions bent in a direction intersecting the longitudinal direction at both ends in the longitudinal direction, and projecting edges in the direction intersecting the longitudinal direction formed at both end edges of the curved portion; A pair of trailing arms having a beam joining portion that is overlapped and connected to the curved portions at both ends of the beam, and a protruding edge portion that protrudes in the same direction as the protruding edge portion of the torsion beam at the end portion of the beam joining portion; With
The trailing arm is overlapped with the curved portion of the torsion beam so as to be opposed to a first joint portion where a distal end of the curved portion of the torsion beam is joined, and an axial end surface of the protruding edge portion of the trailing arm. A torsion beam suspension, comprising: a second joining portion joined by joining end faces in the axial direction of the protruding edge portions of the torsion beam.   The torsion beam suspension according to claim 1, wherein the protruding edge of the trailing arm and the protruding edge of the torsion beam have substantially the same length in the protruding direction.   2. The torsion beam suspension according to claim 1, wherein the trailing edge of the trailing arm and the protruding edge of the torsion beam have substantially the same thickness.   The torsion beam suspension according to any one of claims 1 to 3, wherein a joint portion of the trailing arm with the torsion beam is inclined with respect to a reference line extending in a longitudinal direction of the torsion beam. . The inclined portion of the joint portion of the trailing arm with the torsion beam is provided with a non-opening side on the vehicle body center side in the longitudinal direction of the torsion beam with respect to the opening side of the inclined portion. 5. The torsion beam type suspension according to any one of 4 above. The length in the height direction from the non-opening side to the opening side of the joint portion of the trailing arm with the torsion beam and the length in the height direction of the torsion beam are set to be substantially the same. The torsion beam suspension according to any one of items 5 to 5.   The torsion beam suspension according to any one of claims 1 to 6, wherein a gap is provided between the trailing arm and the torsion beam in the vicinity of the first joint. 8. The gap according to claim 1, wherein a gap is provided between a wall portion serving as a locking portion of the trailing arm in the first joint portion and an end surface of the torsion beam. 9. Torsion beam suspension. The whole circumference is welded to the wall part used as the latching | locking part of the said trailing arm in the said 1st junction part, and the end surface of the said torsion beam , The Claim 1 characterized by the above-mentioned. Torsion beam suspension.   10. The torsion beam suspension according to claim 1, wherein a periphery of a tip edge portion of the joint portion of the trailing arm and the inner wall surface of the torsion beam are welded. The torsion beam suspension according to any one of claims 1 to 10, wherein an opening is provided in a joint portion of the trailing arm.

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