Torsion beam

Abstract

Regarding the torsion beam, the deformation of the reinforcement is suppressed. [Solution] The disclosed torsion beam 2 comprises a beam body 3, a reinforcement 4, a circular weld 41, and a linear weld 42. The beam body 3 connects a pair of left and right trailing arms 1. The reinforcement 4 reinforces the connection point between the trailing arms 1 and the beam body 3. The circular weld 41 is formed by welding the reinforcement 4 to a beam hole 6 drilled in the beam body 3. The linear weld 42 is formed by linearly welding the front and rear end edges 15 of the reinforcement 4 to the beam body 3 and extends further inward in the vehicle width direction than the circular weld 41. The inner end edge 16 of the reinforcement 4 has a recess 17. The recess 17 is shaped to approach the circular weld 41 in the center of the vehicle's longitudinal direction and is recessed outward in the vehicle width direction than the welded end of the linear weld 42.

Description

Technical Field

[0001] This relates to a torsion beam included in a torsion beam type suspension of a vehicle.

Background Art

[0002] A torsion beam type suspension of a vehicle includes a pair of left and right trailing arms that support the left and right wheels and a torsion beam. The torsion beam includes a beam body that connects between the left and right trailing arms, and reinforcements (reinforcement members) that reinforce both left and right end portions of the beam body. The reinforcements are welded and fixed to the beam body, for example, by plug welding or circumferential welding, in order to increase the rigidity of the beam body (see Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, since the movement of the reinforcement with respect to the beam body is restricted, a large strain may occur between the fixed portion (welding portion to the beam body) of the reinforcement and the non-fixed portion that is not welded, and high stress may be generated. For example, when the beam body is twisted, stress may concentrate in the vicinity of the inner end side in the vehicle width direction of the reinforcement, and there is a risk of deformation or cracking.

[0005] One of the objectives of this invention is to suppress reinforcement deformation in a torsion beam, which was devised in light of the problems described above. However, other objectives of this invention include achieving effects and benefits that cannot be obtained with conventional technology, derived from the various configurations shown in the "Modes for Carrying Out the Invention" section below. [Means for solving the problem]

[0006] The disclosed torsion beam can be realized in the embodiments (application examples) disclosed below, and solves at least some of the above problems. Each of embodiments from Embodiment 2 onward is an additional embodiment that can be appropriately selected and each of them is an embodiment that can be omitted. None of embodiments from Embodiment 2 onward disclose any embodiments or configurations that are essential to this case.

[0007] Embodiment 1. The torsion beam disclosed comprises a beam body, a reinforcement, a circular weld, and a linear weld. The beam body connects a pair of left and right trailing arms in a torsion beam suspension of a vehicle. Each of the reinforcements reinforces the connection point between the trailing arm and the beam body. The circular weld is formed by welding a beam hole drilled in the beam body to each of the reinforcements.

[0008] The linear weld is formed by linearly welding the front and rear ends of each reinforcement, which are the ends in the vehicle's longitudinal direction, to the beam body, and extends inward in the vehicle width direction from the circular weld. The inner end of each reinforcement, which is the end in the vehicle width direction, has a recess. The recess is shaped to approach the circular weld at the center of the vehicle's longitudinal direction, and is recessed outward in the vehicle width direction from the weld end, which is the end of the linear weld on the vehicle width direction.

[0009] Embodiment 2. With respect to embodiments including Embodiment 1 described above, it is preferable that the inner edge has a shape that separates from the circular welded portion at both ends in the vehicle's longitudinal direction and has a protrusion that is formed to extend inward in the vehicle width direction from the welded end. Embodiment 3. With respect to embodiments including Embodiment 1 described above, it is preferable that each of the reinforcements has a rib between the circular weld and the weld end that bulges downward and is separated from the beam body. Embodiment 4. With respect to embodiments including Embodiment 1 described above, it is preferable that the ribs extend in the vehicle width direction at the front and rear of the circular welded portion of the vehicle. [Effects of the Invention]

[0010] This can suppress the deformation of the reinforcement in a torsion beam. [Brief explanation of the drawing]

[0011] [Figure 1] This is a top perspective view showing the configuration of the suspension system. [Figure 2] Figure 1 is a bottom view of the suspension system. [Figure 3] This is a perspective view of the beam itself. [Figure 4] This is a cross-sectional view of the beam itself (corresponding to the AA section in Figure 2). [Figure 5] This is a cross-sectional view of the trailing arm and the beam body (corresponding to the BB cross-section in Figure 2). [Figure 6] This is a perspective view of the left-hand reinforcement. [Figure 7] Figure 4 is a cross-sectional view with added reinforcement (cross-sectional view AA in Figure 2). [Figure 8] Figure 5 is a cross-sectional view with added reinforcement (BB cross-sectional view in Figure 2). [Figure 9] This is a bottom view with the right-side reinforcement attached. [Modes for carrying out the invention]

[0012] [1. Structure] The suspension device 30 of this embodiment is applied to a vehicle. The suspension device 30 is also called a torsion beam type suspension and is a kind of swing arm type suspension. FIG. 1 is a top perspective view showing the configuration of the suspension device 30. The suspension device 30 includes a pair of left and right trailing arms 1 that support each of the left and right wheels of the vehicle, and a torsion beam 2 (cross beam) that connects these trailing arms 1 in the vehicle width direction.

[0013] The trailing arm 1 is a hollow arm-shaped member that supports each of the left and right wheels so as to be swingable with respect to the vehicle body. A pair of trailing arms 1 are provided on the left and right. The left trailing arm 1 supports the left wheel, and the right trailing arm 1 supports the right wheel. The front end portion of each trailing arm 1 is pivotally supported by the vehicle body via a bush (not shown). The axles of the left and right wheels are supported at the rear end portions of the respective trailing arms 1. A shock absorber (spring, damper) (not shown) is interposed between the vicinity of the rear end portion of each trailing arm 1 and the vehicle body.

[0014] The torsion beam 2 is a beam-shaped member that connects the left and right trailing arms 1. The torsion beam 2 functions as a stabilizer that suppresses the roll of the vehicle body. The torsion beam 2 acts to suppress an increase in the difference when a difference occurs in the stroke amounts of the left and right shock absorbers. The torsion beam 2 of this embodiment includes a beam body 3 and a reinforcement 4.

[0015] The beam body 3 is a main constituent member of the torsion beam 2. The beam body 3 is a member that connects between the pair of left and right trailing arms 1. Both end portions of the beam body 3 are connected to the left and right trailing arms 1. The beam body 3 has, for example, a groove shape with a U-shaped cross section. The reinforcement 4 is a member that reinforces the connection portions between each of the left and right trailing arms 1 and the beam body 3. The reinforcement 4 is provided on the lower surface side of the beam body 3 at each of the left and right end portions of the beam body 3.

[0016] FIG. 2 is a bottom view of the suspension device 30 in FIG. 1. FIG. 2 shows a state where the left reinforcement 4 is removed. The position where the left reinforcement 4 is attached is the position indicated by the dashed line in FIG. 2. Each reinforcement 4 is arranged so as to overlap the trailing arm 1 and the beam body 3 in a bottom view, and is welded and fixed to each of the trailing arm 1 and the beam body 3.

[0017] FIGS. 3 to 5 are diagrams for explaining the configuration of the beam body 3. FIG. 3 is a perspective view of the beam body 3 viewed from above. FIG. 4 is a cross-sectional view (a view corresponding to the A-A cross-section in FIG. 2) when the beam body 3 is cut along a plane dividing it in the vehicle width direction. FIG. 5 is a cross-sectional view (a view corresponding to the B-B cross-section in FIG. 2) when the trailing arm 1 and the beam body 3 are cut along a plane dividing them in the vehicle longitudinal direction. FIG. 5 shows a state where the reinforcement 4 is removed.

[0018] As shown in FIGS. 3 and 4, the beam body 3 is arranged with the open end of the U-shaped cross-section facing downward. The beam body 3 has a beam top surface 5 and a pair of beam wall portions 7. The beam top surface 5 is the surface located on the upper side of the U-shaped cross-section. The beam top surface 5 is arranged, for example, substantially horizontally. A pair of beam holes 6 are drilled in the beam top surface 5. The beam holes 6 are used for welding and fixing the beam body 3 and the reinforcement 4. The beam wall portion 7 is a surface vertically provided downward from the front end side and the rear end side of the beam top surface 5. The pair of beam wall portions 7 are arranged, for example, substantially vertically in a parallel state to each other.

[0019] As shown in FIG. 3, upper joining portions 8 are provided at both ends in the vehicle width direction on the beam top surface 5. The upper joining portion 8 is a planar portion that is welded and fixed to the trailing arm 1. As shown in FIG. 5, the upper joining portion 8 is welded and fixed in a state of surface contact with the arm upper surface 10 of the trailing arm 1.

[0020] As shown in Figure 3, lower joints 9 are provided at both ends of the beam wall 7 in the vehicle width direction. The lower joints 9 are arm-shaped portions formed to support the trailing arm 1 from below and are welded and fixed to the trailing arm 1. As shown in Figure 5, the lower joints 9 are provided so as to contact the lower surface 11 of the trailing arm 1 and are welded and fixed to the lower surface 11 of the arm.

[0021] Figures 6 to 9 are diagrams illustrating the configuration of the reinforcement 4. Figure 6 is a perspective view of the left reinforcement 4 viewed from above. Figure 7 is a cross-sectional view (section AA in Figure 2) of the beam body 3 and reinforcement 4 when cut by a plane dividing them in the vehicle width direction. Figure 8 is a cross-sectional view (section BB in Figure 2) of the trailing arm 1, beam body 3, and reinforcement 4 when cut by a plane dividing them in the vehicle longitudinal direction. Figure 9 is a bottom view of the right reinforcement 4 in its installed state. Note that the beam body 3 and the left and right reinforcements 4 are configured symmetrically.

[0022] As shown in Figure 6, the reinforcement 4 has an upper joint 12 and a lower joint 13. As shown in Figures 6 and 7, the upper joint 12 is the part that is welded and fixed to the beam top surface 5 of the beam body 3. The upper joint 12 is positioned to make surface contact with the area around the beam hole 6 on the beam top surface 5. A reinforcement hole 14 is drilled in the upper joint 12. The shape of the reinforcement hole 14 is smaller than the shape of the beam hole 6. The reinforcement 4 is positioned so that the reinforcement hole 14 fits inside the beam hole 6.

[0023] As shown in Figure 6, the lower joint portion 13 is the part that is welded and fixed to the lower surface 11 of the trailing arm 1. As shown in Figures 6 and 8, the lower joint portion 13 is positioned to make surface contact with the lower surface 11 of the arm. Of the lower joint portion 13, the outer end edge 20, which is the outer end edge in the vehicle width direction of the reinforcement 4, is linearly welded and fixed to the lower surface 11 of the arm.

[0024] As shown in Figures 7 to 9, the reinforcement 4 of this embodiment includes a circular weld 41 and a linear weld 42 as welding points between the beam body 3 and the reinforcement 4. The circular weld 41 is a portion formed by welding a beam hole 6 drilled in the beam body 3 to the reinforcement 4. The circular weld 41 may be formed by welding the inner periphery of the beam hole 6 to the upper joint portion 12 of the reinforcement 4 in an annular shape, or by welding the entire interior of the beam hole 6 in a plug shape. In other words, the circular weld 41 may be an annular weld formed by welding in an annular shape, or it may be a plug weld formed by plug welding (plug welding). The circular weld 41 shown in Figures 7 to 9 is the former.

[0025] The linear weld 42 is a portion formed by linearly welding the front and rear end edges 15, which are the vehicle's longitudinal end edges of the reinforcement 4, to the beam wall portion 7 of the beam body 3. As shown in Figures 8 and 9, the linear weld 42 extends in the vehicle width direction along the front and rear end edges 15 of the reinforcement 4. The outer end of the linear weld 42 in the vehicle width direction is located below the trailing arm 1, and the inner end of the linear weld 42 in the vehicle width direction is located inward from the circular weld 41. The dotted line L in Figure 9 indicates the position of the inner end (welded end) of the linear weld 42 in the vehicle width direction. The circular weld 41 is located outward from the dotted line L in the vehicle width direction.

[0026] The inner end edge 16 of the reinforcement 4, which is the inner end edge in the vehicle width direction, is not welded to the beam body 3. In addition, as shown in Figures 6 and 9, the inner end edge 16 is provided with a recess 17 and a protrusion 18. The recess 17 is a portion formed in a shape that is recessed outward in the vehicle width direction from the dashed line L in Figure 9. As shown in Figure 9, the recess 17 is formed by bringing the inner edge 16 closer to the circular welded portion 41 at the center of the inner edge 16 in the vehicle's longitudinal direction. The protrusion 18 is a portion formed to protrude inward in the vehicle width direction from the imaginary line L in Figure 9. As shown in Figure 9, the protrusion 18 is formed by separating the inner end edge 16 from the circular welded portion 41 at both ends of the inner end edge 16 in the vehicle longitudinal direction.

[0027] The reinforcement 4 has ribs 19. The ribs 19 are portions provided at least between the welded ends of the circular weld 41 and the linear weld 42 (the inner end of the linear weld 42 in the vehicle width direction), and are formed in a shape that bulges downward and separates from the beam body 3. The ribs 19 function to suppress localized stress concentration between the welded ends of the circular weld 41 and the linear weld 42 of the reinforcement 4 when the beam body 3 undergoes torsional deformation.

[0028] As shown in Figures 6 and 9, the rib 19 in this embodiment extends in the vehicle width direction at both the front and rear ends of the circular weld 41. Therefore, as shown in Figure 7, a gap is created between the beam body 3 and the reinforcement 4 at both the front and rear ends of the circular weld 41. This gap alleviates stress concentration around the circular weld 41 within the reinforcement 4.

[0029] [2. Effects] (1) The torsion beam 2 described above comprises a beam body 3, a reinforcement 4, a circular welded section 41, and a linear welded section 42. The beam body 3 connects a pair of left and right trailing arms 1 in the vehicle's torsion beam suspension (suspension device 30). The pair of left and right reinforcements 4 reinforce the connection points between each of the left and right trailing arms 1 and the beam body 3. The circular welded section 41 is formed by welding a beam hole 6 drilled in the beam body 3 to the reinforcement 4. The linear welded section 42 is formed by linearly welding the front and rear ends 15, which are the ends of the reinforcement 4 in the vehicle's longitudinal direction, to the beam body 3, and extends further inward in the vehicle width direction than the circular welded section 41.

[0030] The inner edge 16 of the reinforcement 4, which is the inner edge in the vehicle width direction, has a recess 17. The recess 17 is shaped to approach the circular weld 41 at the center of the inner edge 16 in the vehicle longitudinal direction, and is formed to be recessed outward in the vehicle width direction than the weld end, which is the inner edge of the linear weld 42 in the vehicle width direction. In other words, the recess 17 is formed to be recessed outward in the vehicle width direction than the imaginary line L in Figure 9.

[0031] In this way, by bringing the inner edge 16 of the reinforcement 4 closer to the highly rigid circular weld 41, strain in the vicinity of the inner edge 16 of the reinforcement 4 can be mitigated. Therefore, deformation, cracking, and failure of the reinforcement 4 in the torsion beam 2 can be suppressed. Furthermore, by extending the linear weld 42 of the reinforcement 4 further inward in the vehicle width direction than the circular weld 41, the torsional rigidity of the beam body 3 can be improved, thereby improving the performance of the suspension device 30.

[0032] (2) A protrusion 18 is provided on the inner end edge 16 of the reinforcement 4. The protrusion 18 is shaped to be separated from the circular weld 41 at both ends of the inner end edge 16 in the vehicle longitudinal direction, and is formed to protrude inward in the vehicle width direction from the weld end, which is the inner end of the linear weld 42 in the vehicle width direction. In other words, the protrusion 18 is formed to protrude inward in the vehicle width direction from the imaginary line L in Figure 9.

[0033] In this way, by providing protrusions 18 before and after the recess 17, and separating the inner end edge 16 of the reinforcement 4 from the circular weld 41, strain near the weld end, which is the inner end of the linear weld 42 in the vehicle width direction, can be mitigated. Therefore, the occurrence of deformation, cracking, and breakage of the reinforcement 4 can be suppressed.

[0034] (3) The reinforcement 4 described above has ribs 19. The ribs 19 are provided between the circular weld 41 and the weld end, which is the inner end in the vehicle width direction of the linear weld 42. The ribs 19 have a shape that bulges downward and separates from the beam body 3. By providing such ribs 19, it is possible to suppress localized stress concentration between the circular weld 41 and the weld end of the linear weld 42 of the reinforcement 4. Therefore, the occurrence of deformation, cracks, and failures of the reinforcement 4 can be suppressed.

[0035] (4) As shown in Figure 9, the ribs 19 extend in the vehicle width direction at the front and rear of the circular weld 41. This reduces stress concentration around the circular weld 41 of the reinforcement 4. Therefore, deformation, cracking, and failure of the reinforcement 4 can be suppressed.

[0036] [3. Others] The above embodiments are merely illustrative examples, and there is no intention to exclude various modifications or applications of techniques not explicitly stated in these embodiments. Each configuration of these embodiments can be modified in various ways without departing from their intended purpose. Furthermore, each configuration of these embodiments can be selected or combined as needed.

[0037] In the above embodiment, a structure in which the reinforcement 4 is fixed to the lower side of the beam body 3 is shown, but it is also possible to fix the reinforcement 4 to the upper side of the beam body 3. For example, if the beam body 3 is positioned with the open end of its U-shaped cross-section facing upward, the reinforcement 4 can be fixed to its upper side. The structures of the beam body 3 and the reinforcement 4 are reversible in the vertical direction.

[0038] Furthermore, in the above embodiment, a circular welded portion 41 is shown, which is formed by welding the inner periphery of the beam hole 6 formed in the beam body 3 and the upper joint portion 12 of the reinforcement 4 in an annular shape. However, the entire interior of the beam hole 6 may be plug welded. Alternatively, the shape of the reinforcement hole 14 formed in the reinforcement 4 may be made larger than the shape of the beam hole 6, and the inner periphery of the reinforcement hole 14 and the beam top surface 5 may be welded in an annular shape. Or, the entire interior of the reinforcement hole 14 may be plug welded. [Industrial applicability]

[0039] This invention is applicable to the torsion beam manufacturing industry. It is also applicable to the torsion beam suspension manufacturing industry, including the torsion beam itself. Furthermore, it is applicable to the vehicle manufacturing industry, which utilizes the torsion beam suspension. [Explanation of Symbols]

[0040] 1 Trailing Arm 2 Torsion beam 3. Beam body 4 Reinforce 5. Beam top surface 6 beam holes 7. Beam wall section 8 Upper joint 9 Lower joint 10. Top surface of the arm 11. Underside of the arm 12 Upper joint 13 Lower joint 14 Reinforcement holes 15 Front and rear edges 16 Inner edge 17 Recess 18 Convex part 19 Ribs 20 Outer edge 30. Suspension system (torsion beam type suspension) 41 Circular weld 42 Linear weld

Claims

1. In a vehicle's torsion beam suspension, the beam body connects a pair of left and right trailing arms, Reinforcements that reinforce the connection points between each of the trailing arms and the beam body, A circular welded portion is formed by welding the beam holes drilled in the beam body to each of the reinforcements, Each of the aforementioned reinforcements has a linear welded portion that extends inward in the vehicle width direction from the circular weld portion, and is formed by linearly welding the front and rear ends, which are the ends of the reinforcement in the vehicle's longitudinal direction, to the beam body. Each of the aforementioned reinforcements has an inner edge, which is the inner edge in the vehicle width direction, that approaches the circular weld at the center in the vehicle's longitudinal direction, and has a recess formed in a shape that is recessed outward in the vehicle width direction than the weld end, which is the inner edge in the vehicle width direction of the linear weld. A torsion beam characterized by the following features.

2. The inner edge has a shape that separates from the circular weld at both ends in the vehicle's longitudinal direction, and has a protrusion that is formed to extend inward in the vehicle width direction from the weld end. A torsion beam according to claim 1, characterized in that...

3. Each of the reinforcements has a rib between the circular weld and the weld end that bulges downward and separates from the beam body. A torsion beam according to claim 1, characterized in that

4. The ribs extend in the vehicle width direction at the front and rear of the circular welded portion. The torsion beam according to claim 3, characterized in that

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