JP2019172201A - Torsion beam type suspension - Google Patents

Abstract

To prevent melt-down of a tip when welding a fork-shaped reinforcing member for reinforcing connection of a trailing arm and a torsion beam, and to make positioning of an attachment position easy.SOLUTION: A torsion beam type suspension comprises: a pair of trailing arms which is arranged with an interval in a vehicle width direction; a torsion beam linearly extending to the vehicle width direction, and connected to the trailing arm at both ends in an extension direction; and a reinforcing member for reinforcing a connecting part to which the trailing arm and the torsion beam are connected. The torsion beam extends in a gutter shape, the reinforcing member extends in a gutter-shaped portion of the torsion beam so as to be split to a fork part toward a tip part from a base end part, and joined to the trailing arm at the base end part. The vicinity of the tip part of the reinforcing member has a protrusion protruding to an inside of the fork part, and joined to an inner face of the gutter-shaped portion of the torsion beam at both outer sides of the fork part.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a torsion beam type suspension, and more particularly to a reinforcing member for a joint portion between a torsion beam and a trailing arm in a torsion beam type suspension.

  BACKGROUND ART A torsion beam type suspension for an automobile has conventionally been provided with a pair of trailing arms arranged at intervals in the vehicle width direction and a torsion beam provided between the pair of trailing arms and coupled to each other. The trailing arm connected to is allowed to move up and down by torsion beam torsion.

  In the torsion beam suspension, the trailing arm and the torsion beam are generally coupled by arc welding, and as shown in Patent Document 1, a reinforcing member is welded to the coupling portion between the trailing arm and the bowl-shaped torsion beam, Some are reinforced by increasing the bond strength. However, when the reinforcing member is welded, stress concentration may be a problem at the welded portion of the reinforcing member.

  In order to relieve such stress concentration, a plate-like member extending so as to be divided into two forks is used as a reinforcing member, arranged inside the bowl-shaped torsion beam, and the base end of the reinforcing member is welded to the trailing arm, There is also a type in which both outer sides near the bifurcated tip are welded and joined to the inner surface of a bowl-shaped torsion beam. In this reinforcing member, it is possible to disperse the stress rather than dividing the tip side into two.

  In such a bifurcated reinforcing member, since the stress at the bifurcated tip is generally increased, the stress at the tip is reduced by a tapered shape in which the tip is tapered toward the tip. In addition, the fatigue life is extended by setting the end of welding to the front end side.

JP2015-229372A

  However, the reinforcing member with the tip side split into two and the tip is tapered has a problem that the tip end is easily melted down due to heat input of welding because the tip end side that is thinned during welding becomes the welding end. there were. Then, there is a problem that the part where the melt-off has occurred becomes a base point of stress concentration, leading to a decrease in life. Further, in the positioning when welding the reinforcing member, only the base end portion of the reinforcing member placed on the trailing arm side can be fixed, and there is a problem that the variation in the mounting position becomes large.

  The present invention solves these problems and prevents the tip from being melted when welding a bifurcated reinforcing member that relieves stress concentration in a reinforcing member that reinforces the coupling between the trailing arm and the torsion beam. And it aims at providing the reinforcing member which positioning of an attachment position is easy.

  (1) A torsion beam suspension according to the present invention includes a pair of trailing arms arranged at an interval in the width direction of a vehicle, the trailing arm extending in the width direction of the vehicle, and extending at both ends in the extending direction. A torsion beam coupled to an arm; and a reinforcing member that reinforces a coupling portion where the trailing arm and the torsion beam are coupled, wherein the torsion beam extends in a bowl shape, and the reinforcing member includes: The reinforcing member has a bifurcated portion extending so as to be bifurcated from the proximal end portion toward the distal end portion, and the proximal end portion is joined to the trailing arm inside the torsion beam formed in a bowl shape. Protrusions projecting inward of the bifurcated portion are provided in the vicinity of the tip portion of the bifurcated portion, and the outer sides of the bifurcated portion are formed in a bowl shape Characterized in that it is welded to the inner surface of the over arm.

  This torsion beam suspension is capable of dispersing the stress of the reinforcing member by welding both outer sides of the bifurcated portion of the reinforcing member to the inner surface of the saddle-shaped portion of the torsion beam, and also protruding portions projecting inside the bifurcated portion of the reinforcing member By providing this, heat input at the time of welding can be improved, and burn-off near the tip can be suppressed.

  Furthermore, when welding with the reinforcing member fixed at a predetermined position, both the base end and the protruding portion can be fixed by clamping the protruding portion provided near the tip of the bifurcated portion. Can be accurately positioned.

  (2) In the torsion beam suspension described above, the reinforcing member extends in a plate shape, and the vicinity of the tip of the bifurcated portion is located on the inner side of the bifurcated portion so as to be wide in the extending direction of the reinforcing member. It may be protruding. By doing so, the plate-shaped reinforcing member can be welded to disperse the stress of the reinforcing member, and by providing a wide portion protruding inside the bifurcated portion of the reinforcing member, the heat input during welding is improved. In addition, it is possible to suppress melting near the tip.

  (3) In the torsion beam type suspension described above, the weld bead near the tip where the outer sides of the bifurcated part near the tip of the reinforcing member are welded to the inside of the hook-shaped part of the torsion beam You may weld so that it may become so small. By welding in such a manner, the reinforcing member is relaxed in the stress concentration of the weld bead and is firmly joined to the torsion beam.

  (4) A welding method according to the present invention includes a pair of trailing arms arranged at intervals in the width direction of the vehicle, the trailing arms extending in the width direction of the vehicle, and extending at both ends in the extending direction. A torsion beam coupled to the torsion beam, and a reinforcing member that reinforces a coupling part that couples the trailing arm and the torsion beam, wherein the torsion beam extends in a bowl shape, and the reinforcing member Is formed so as to be bifurcated from the base end portion toward the distal end portion, the vicinity of the distal end portion of the reinforcing member has a projecting portion projecting inside the bifurcated portion, and both ends of the torsion beam are connected to the pair of the torsion beams. A joint welding step for welding to the trailing arm of the metal, and the proximal end of the reinforcing member adjacent to the trailing arm so as to be weldable A positioning step for positioning the reinforcing member inside the bowl-shaped portion of the torsion beam, and a base end welding step for welding the base end of the reinforcing member to the trailing arm after the positioning step. And a near-tip welding step of welding the outside of the vicinity of the tip of the reinforcing member to the inside of the bowl-shaped portion of the torsion beam.

  In the welding method for this torsion beam suspension, in the step of welding near the tip, both the outer sides of the bifurcated portion of the reinforcing member are welded to the inner surface of the saddle-shaped portion of the torsion beam. By providing the protruding portion protruding inside the bifurcated portion, it is possible to improve the heat input during welding and to suppress the melt-off near the tip portion.

  (5) In the welding method described above, the welding step near the tip may be characterized in that welding is performed toward the tip so that the rise of the weld bead becomes smaller toward the tip of the reinforcing member. By doing so, the reinforcing member is relaxed in the stress concentration of the weld bead and is firmly coupled to the torsion beam.

  (6) The positioning step may be characterized by clamping and positioning the protruding portion of the reinforcing member. By doing so, in addition to clamping the base end in the positioning step, it is possible to fix both the base end and the protrusion by clamping the protrusion provided near the tip of the bifurcated portion. , Can be positioned accurately.

  According to the present invention, stress can be distributed in the reinforcing member that reinforces the connection between the torsion beam and the trailing arm, heat input during welding can be improved, burn-off near the tip can be suppressed, and positioning of the reinforcing member can be achieved. It is possible to provide a torsion beam suspension that ensures the above.

It is a perspective view of the torsion beam type suspension concerning this embodiment. It is a figure which shows the coupling | bond part of the torsion beam and trailing arm of the torsion beam type suspension shown in FIG. 1, (A) is a sectional side view, (B) shows a bottom view. It is a schematic perspective view which shows the reinforcement member before welding. It is a schematic perspective view which expands and shows the welding state of the front-end | tip part of a torsion beam and a reinforcement member.

  A torsion beam suspension 1 according to an embodiment of the present invention will be described with reference to the drawings.

  The torsion beam type suspension 1 is provided on the rear wheel side of a front-wheel drive vehicle, and has a structure that allows the vertical movement of each trailing arm 10 to which the rear wheel is attached by twisting the torsion beam 20.

  As shown in FIG. 1, the torsion beam suspension 1 includes a pair of trailing arms 10 arranged at intervals in the width direction (left-right direction) of a vehicle body (not shown) and a linear shape in the width direction of the vehicle. A torsion beam 20 extending and coupled to the trailing arm 10 at both ends in the extending direction, and a reinforcing member 30 (see FIGS. 2 and 3) for reinforcing the coupling portion where the trailing arm 10 and the torsion beam 20 are coupled. Is provided.

  The trailing arm 10 includes a bush press-fit portion 11 into which a tubular bush as an elastic member is press-fitted on the front side of the vehicle body. The bush press-fit portion 11 includes a bracket (not shown) and a fixing bolt (not shown). And is swingably attached to the vehicle body. Further, the trailing arm 10 is suspended from the rear side of the vehicle body via a spring (not shown) and a shock absorber (not shown). Furthermore, one end side of the trailing arm 10 supports a rear wheel (not shown) via the axle 12 so as to be rotatable.

  The trailing arm 10 is formed by bending and processing a hollow pipe having a substantially circular cross section using a non-ferrous metal such as an aluminum alloy. The pair of trailing arms 10 are formed to have a symmetrical shape on the left and right.

  As shown in FIG. 2, the torsion beam 20 is formed in a bowl shape having a U-shaped cross section by bending a plate-like member. The torsion beam 20 is provided in a state in which the opening of the portion formed in a bowl shape faces the lower side of the vehicle body, that is, in a bowl shape. Both ends of the torsion beam 20 and the trailing arm 10 are coupled at a coupling portion formed by welding or the like.

  The reinforcing member 30 is a member for forming a reinforcing structure (see FIG. 2) that reinforces the coupling portion between the torsion beam 20 and each trailing arm 10. The reinforcing member 30 is formed, for example, by subjecting a plate material to processing such as pressing.

  As shown in FIG. 3, the reinforcing member 30 has a bifurcated portion 31 extending so as to be divided into a bifurcated shape from the proximal end portion 34 toward the distal end. The reinforcing member 30 can be formed by cutting out a substantially central portion in the width direction (short direction) on the distal end side in the longitudinal direction (extending direction) of the rectangular plate-like body. In this way, the reinforcing member 30 is formed with a bifurcated portion 31 that is bifurcated in the width direction on the distal end side in the longitudinal direction.

  The reinforcing member 30 has a protruding portion 32 that protrudes inwardly (in the width direction) of the bifurcated portion 31 in the vicinity of the distal end portion thereof. The protruding portion 32 protrudes in a rectangular shape toward the inner side in the width direction of the plate member forming the reinforcing member 30. Therefore, the bifurcated portion 31 has a shape (wide shape) that is wide in the width direction of the reinforcing member 30 by the amount of protrusion of the protrusion 32 on the tip side. Further, the reinforcing member 30 before being welded has a tapered leading end portion 33 on the further tip side of the protruding portion 32.

  Referring to FIG. 2 again, the reinforcing member 30 extends in the same direction as the extending direction of the torsion beam 20 such that the proximal end portion 34 is on the trailing arm 10 side and the distal end portion is on the center side of the torsion beam 20. Installed. Thereby, the reinforcing member 30 extends inside the torsion beam 20 formed in a bowl shape from the base end portion 34 toward the tip end portion.

  The reinforcing member 30 is joined by welding the proximal end portion 34 to the trailing arm 10 in the vicinity of the coupling portion. Further, the reinforcing member 30 is joined by welding the outer side of the front end portion of the bifurcated portion to the inner side of the portion of the torsion beam 20 formed in a bowl shape. The reinforcing member 30 is joined to the vicinity of the open portion of the torsion beam 20 formed in a bowl shape, that is, to the lower side of the torsion beam 20.

  As shown in FIG. 4, in this embodiment, when the reinforcing member 30 is fixed by welding, the protruding portion is located in the vicinity of the most distal portion 33 (see FIG. 3B) on the most distal side from the protruding portion 32. The heat is diffused moderately by 32, and melt-down is suppressed at the welded portion 31 a in the vicinity of the distal end portion of the reinforcing member 30. Therefore, it is possible to prevent the reinforcing member 30 from being welded in a desired shape and serving as a stress concentration base point.

  In the vicinity of the tip end welded portion 31a in which both outer sides of the bifurcated portion in the vicinity of the tip end portion are welded to the inside of the hook-shaped portion of the torsion beam 20, the weld bead (blacked portion in FIG. 4) rises toward the tip end. It is welded to make it smaller. In this method, the welding rod is moved toward the tip side so that the tip end side is the end, and welding is performed so that the swell of the weld bead gradually disappears. Thereby, the stress concentration of the weld bead can be suppressed.

  In the torsion beam suspension 1 according to the present embodiment, when welding the torsion beam 20 and the trailing arm 10, first, both ends of the torsion beam 20 are welded to the pair of trailing arms 10 (joint welding step). . Specifically, the torsion beam 20 is formed so that the shape of its end matches the outer shape of the trailing arm 10. Therefore, in the joining portion welding step, the end of the torsion beam 20 is brought into contact with the outer shape of the trading arm 10 and welding is performed along the shape of the end of the torsion beam 20 in this state. Thereby, a pair of trailing arms 10 are welded to both ends of the torsion beam 20.

  Thereafter, the reinforcing member 30 is positioned inside a portion of the torsion beam 20 formed in a bowl shape so that the base end portion of the reinforcing member 30 is adjacent to the trailing arm 10 (positioning step). In the present embodiment, in the positioning step, the base end portion 34 of the reinforcing member 30 is clamped and positioned at a predetermined position, and the protruding portion 32 of the reinforcing member 30 is clamped and positioned. As a result, the reinforcing member 30 is fixed at both the proximal end portion 34 and the distal end portion, so that accurate positioning is possible.

  Then, after the positioning step, the base end portion 34 of the reinforcing member 30 is welded to the trailing arm 10 (base end welding step). In the proximal end welding step, the shape of the proximal end portion 34 of the reinforcing member 30 is formed so as to match the shape of the trailing arm 10, and welding is performed along the shape of the proximal end portion 34 of the reinforcing member 30. . Thereby, the trailing arm 10 and the reinforcing member 30 are joined.

  Thereafter, the outside of the vicinity of the tip of the reinforcing member 30 is welded to the inside of the portion of the torsion beam 20 formed in a bowl shape (welding step near the tip). In the vicinity of the distal end welding step, welding is performed from the proximal end side toward the distal end side so that the rise of the weld bead becomes smaller toward the distal end of the reinforcing member 30. Thereby, the stress concentration of the weld bead is suppressed, and the torsion beam 20 and the reinforcing member 30 are joined.

  In the present embodiment, the welding has been described assuming so-called arc welding. However, if strength is obtained, welding may be performed by other methods.

  In the present embodiment, the example in which the torsion beam suspension 1 is applied to the rear wheels of the front wheel drive vehicle has been described. However, the torsion beam type suspension may be used for a rear wheel of a four-wheel drive vehicle, or may be used for a vehicle of another drive method or a front wheel.

  In the present embodiment, the bifurcated portion is formed in a U shape. However, the bifurcated portion may be V-shaped or other shape as long as the stress can be dispersed. Moreover, although the protrusion part 32 protrudes in the rectangle, you may protrude in the state where the front-end | tip was roundish.

However, the configuration shown in each of the above embodiments is a specific example of the component, and each configuration, shape, or mounting mode is limited to that shown as the embodiment unless departing from the gist of the present invention. Various modifications or changes are possible.

  The present invention can be used for a torsion beam suspension.

DESCRIPTION OF SYMBOLS 1 Torsion beam type suspension 10 Trailing arm 20 Torsion beam 30 Reinforcement member 31 Fork part 32 Projection part 34 Base end part

Claims (1)

A pair of trailing arms arranged at an interval in the width direction of the vehicle;
A torsion beam extending in the width direction of the vehicle and coupled to the trailing arm at both ends in the extending direction;
A torsion beam suspension comprising a reinforcing member that reinforces a coupling portion where the trailing arm and the torsion beam are coupled;
The torsion beam extends in a bowl shape,
The reinforcing member has a bifurcated portion extending so as to be bifurcated from the proximal end portion toward the distal end portion, and the proximal end portion is joined to the trailing arm inside the hook-shaped portion of the torsion beam. Has been
In the vicinity of the tip of the reinforcing member, there is provided a protruding portion that protrudes inside the bifurcated portion
A torsion beam suspension, characterized in that both outer sides of the bifurcated portion are welded to the inner surface of a portion of the torsion beam formed in a bowl shape.

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