JP2008007063A - Structure of mounting part of suspension arm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a mounting part of a suspension arm capable of compatibly ensuring the deformation strength/fatigue strength when a vehicle travels and reducing the deformation resistance when the vehicle is assembled. <P>SOLUTION: In a mounting bracket 16 for mounting a bush 28 at a fore end of a first arm part 24B of a lower arm 24, the strength and the rigidity of a first side wall part 18 are set to be lower than those of a second side wall part 20. Thus, the first side wall part 18 can be easily deformed, and the deformation resistance during the assembly can be reduced. On the other hand, the second side wall part 20 is reinforced by setting a second flange part 20A, the deformation strength/the fatigue strength when a vehicle travels is ensured. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a structure for attaching a suspension arm.

Japanese Patent Application Laid-Open No. H10-228561 discloses a technique for curing a suspension arm mounting bracket to give a necessary strength.
JP 2004-98766 A

  However, according to the above prior art, there is room for improvement in the following points.

  That is, from the viewpoint of securing the deformation strength and fatigue strength of the bracket after the suspension arm is assembled, it is necessary to increase the rigidity of the bracket in advance. On the other hand, considering that the bush of the suspension arm is assembled to the bracket, it is preferable that the deformation resistance of the side portion of the bracket is small. However, decreasing the deformation resistance decreases the rigidity of the bracket. Thus, the suspension arm bracket is required to have a contradictory performance. Therefore, if the emphasis is placed only on increasing the rigidity of the bracket as in the prior art, the deformation resistance will increase. To cope with this, the bolt diameter of the fastening bolt of the bush is increased to increase the axial force. However, when considering the assembly process including bolt tightening in the factory line, the bolt diameter is naturally limited.

  In consideration of the above-described facts, an object of the present invention is to provide a suspension arm mounting portion structure capable of ensuring both deformation strength and fatigue strength during vehicle travel and reduction in deformation resistance during vehicle assembly. .

  The suspension arm mounting portion structure according to the first aspect of the present invention includes a bush provided at the arm tip of the suspension arm, a first support portion supported on the vehicle body side, and sandwiching the bush from both ends in the axial direction. A second support part, and a fastener for fastening the first support part and the second support part in the bush axis direction with the bush sandwiched between the first support part and the second support part. A suspension arm mounting portion structure including the first support portion, wherein the rigidity in the bush axis direction of the first support portion is set lower than the rigidity of the second support portion in the bush axis direction. To do.

  According to a second aspect of the present invention, in the suspension arm mounting portion structure according to the first aspect, the first support portion is formed in a flat plate shape, and the second support portion includes the second support portion. The reinforcing means for increasing the rigidity in the bush axis direction is set.

  According to the first aspect of the present invention, when the bush provided at the arm tip portion of the suspension arm is attached to the first support portion and the second support portion supported on the vehicle body side, the first support After the bush is inserted between the first support portion and the second support portion, the first support portion and the second support portion may be tightened in the bush axis direction with a fastener. Accordingly, the bush is attached to the first support portion and the second support portion while being sandwiched between the first support portion and the second support portion.

  Here, in the present invention, since the rigidity of the first support portion in the bush axis direction is set lower than the rigidity of the second support portion in the bush axis direction, the first support portion is the second support portion. Rather than in the bush axis direction. Therefore, by utilizing this relative rigidity difference, the deformation resistance at the time of assembly (at the time of fastening) is lowered on the first support portion side, so that it can be easily deformed when the fastening torque of the fastener is applied. It becomes possible.

  On the other hand, the deformation strength and fatigue strength required when the vehicle travels after assembling may be ensured on the second support portion side that is relatively highly rigid.

  According to the second aspect of the present invention, the first support portion is configured in a flat plate shape, and the second support portion is provided with reinforcing means for increasing the rigidity in the bush axis direction. The rigidity of the support portion in the bush axis direction can be adjusted by the plate thickness, and the rigidity of the second support portion in the bush axis direction can be adjusted by the degree of reinforcement of the reinforcing means (how to reinforce).

  As described above, the suspension arm attachment portion structure according to claim 1 is excellent in that it is possible to satisfy both of securing of deformation strength and fatigue strength during vehicle traveling and reduction of deformation resistance during vehicle assembly. Has an effect.

  The suspension arm mounting portion structure according to the second aspect of the present invention can relatively easily secure deformation strength / fatigue strength during vehicle travel and reduce deformation resistance during vehicle assembly. It has an excellent effect.

  Hereinafter, an embodiment to which a suspension arm mounting portion structure according to the present invention is applied will be described with reference to FIGS. In these drawings, an arrow FR appropriately shown indicates the vehicle front side, an arrow UP indicates the vehicle upper side, and an arrow IN indicates the vehicle width direction inner side.

  FIG. 4 shows the overall configuration of the rear suspension 10. As shown in this figure, the rear suspension 10 includes a pair of left and right rear suspension side rails 12 as parts on the body side. The rear suspension side rail 12 is a long body frame member extending along the vehicle longitudinal direction, and includes a front portion 12A disposed on the vehicle body upper side, a rear portion 12B disposed on the vehicle body lower side, The intermediate portion 12C that obliquely connects the portion 12A and the rear portion 12B. The rear end portions of the left and right rear suspension side rails 12 are connected in the vehicle width direction by a rear suspension cross member 14 formed in a substantially hat shape with an intermediate portion recessed downward as viewed from the vehicle front side. .

  A mounting bracket 16 is attached to the outer side wall of the rear portion 12B of the rear suspension side rail 12 described above by welding. As shown in FIGS. 2 and 3, the mounting bracket 16 is formed in a substantially U-shaped cross section with the lower side opened when viewed from the side of the vehicle, and a first side wall as a pair of front and rear first support portions. Part 18 and a second side wall part 20 as a second support part, and a top wall part 22 that connects the upper end parts of the first side wall part 18 and the second side wall part 20 in the vehicle front-rear direction. Has been. An inner end portion of a lower arm 24 as a suspension arm is pivotably supported between a pair of front and rear first side wall portions 18 and second side wall portions 20 of the mounting bracket 16.

  Returning to FIG. 4, the lower arm 24 includes a base end portion 24 </ b> A disposed on the outer side in the vehicle width direction, a first arm portion 24 </ b> B extending from the base end portion 24 </ b> A toward the vehicle rear side in the vehicle width direction, A second arm portion 24C that extends from the portion 24A toward the vehicle front side on the inner side in the vehicle width direction. A lower end portion of the steering knuckle 26 is pivotally supported by the base end portion 24A so as to be swingable. Furthermore, bushes 28 are attached to the distal end portion of the first arm portion 24B and the distal end portion of the second arm portion 24C, respectively, by welding.

  FIG. 1 is a plan view schematically showing the suspension arm attachment structure according to the present embodiment. As shown in this figure, the bush 28 includes a cylindrical inner cylinder 30 disposed in the shaft core portion, a concentric circle disposed on the outer peripheral portion of the inner cylinder 30, and an axial dimension of the inner tube 30. The outer cylinder 32 set shorter than the directional dimension, and the elastic body 34 interposed between the inner cylinder 30 and the outer cylinder 32 and vulcanized and bonded to each other are provided. The outer cylinder 32 is attached to the distal end portion of the first arm portion 24B and the distal end portion of the second arm portion 24C of the lower arm 24 by welding.

  On the other hand, as shown in FIGS. 2 and 3, a bolt insertion hole 36 and a positioning pin insertion hole 38 are coaxially formed in the pair of front and rear first side wall 18 and second side wall 20 of the mounting bracket 16 described above. Is formed. Then, with the bush 28 inserted between the pair of front and rear first side wall portions 18 and second side wall portions 20, bolts formed in the inner cylinder 30 and both the first side wall portions 18 and the second side wall portions 20 are inserted. The hole 36 is coaxially positioned, and the bush 28 is fastened and fixed between the pair of front and rear side walls 18 and 20 by bolts 40 and nuts 42 as fasteners. Thus, the lower arm 24 is configured to be pivotally supported by the rear suspension side rail 12 so as to be swingable in the vehicle vertical direction around the inner ends of the first arm portion 24B and the second arm portion 24C.

  Here, the configuration of the mounting bracket 16 described above will be described in detail.

  First, the main configuration of the mounting bracket 16 according to the present embodiment will be described with reference to FIG. 1 shown in the schematic view. A pair of front and rear first side wall portions 18 and a first side wall portion 18 are provided on the side portion of the rear suspension side rail 12. The first member 50 and the second member 52 corresponding to the two side wall portions 20 are fixed by welding. The direction of the plates of the first member 50 and the second member 52 is a vehicle width direction that is a direction orthogonal to the rear suspension side rail 12.

  The first member 50 is constituted by a flat plate. On the other hand, the second member 52 is provided with a reinforcing member 54 as a reinforcing means on the bottom surface of the flat plate. The setting method of the reinforcing member 54 is arbitrary. For example, when the second member 52 is press-molded, the reinforcing member 54 is punched into a shape including the reinforcing member 54 and bent in advance, so that the flat plate-like second member 52 is viewed in plan view. Right-angled triangular reinforcing plates may be formed orthogonally, or the second member 52 and the reinforcing member 54 may be formed as separate members, and the reinforcing member 54 is joined to the second member 52 by a joining means such as welding. And the rear suspension side rail 12 may be welded.

  With the above configuration, the strength and rigidity of the first member 50 in the bush axis direction are lower than the strength and rigidity of the second member 52 in the bush axis direction. That is, a relative strength difference and a rigidity difference are set between the first member 50 and the second member 52, and the first member 50 is easily deformed with respect to the load in the bush axis direction. The member 52 has a property that it is difficult to be deformed with respect to a load in the bush axis direction.

  Supplementally, the first member 50 and the second member are arranged such that the first member 50 having the lower deformation resistance is arranged on the vehicle front side and the second member 52 having the higher deformation resistance is arranged on the vehicle rear side. The positional relationship before and after 52 is defined. The reason for this is that, as shown in FIG. 4, the lower arm 24 includes a first arm portion 24B and a second arm portion 24C, but in the first arm portion 24B disposed on the vehicle rear side, the front / rear input is performed. At the time of forward displacement, before the outer cylinder 32 of the bush 28 on the first arm portion 24B side comes into contact with the first member 50, the first arm is brought into a bottomed state between the bush 28 on the second arm portion 24C side and the mounting bracket. Since the relative displacement of the bush 28 on the side of the portion 24B is restricted, the strength and rigidity of the first member 50 may be low. On the other hand, at the time of backward displacement at the time of front-rear input, the bush 28 on the first arm portion 24B side. This is because the outer cylinder 32 comes into contact with the second member 52 of the mounting bracket 16 and comes to the bottom, so that the second member 52 side needs to be highly rigid so that the deformation resistance is increased.

  2 and 3, in the actual mounting bracket 16, the first flange portion 18 </ b> A and the first flange portion 18 </ b> A by bending are attached to the lower ends of the pair of front and rear first side wall portions 18 and second side wall portions 20 of the mounting bracket 16 having an open cross section. Two flange portions 20A are integrally formed. Further, the first flange portion 18 </ b> A of the first side wall portion 18 and the second flange portion 20 </ b> A of the second side wall portion 20 are connected by a flat plate-like reinforcing additional plate 60. In other words, the reinforcing additional plate 60 is arranged (welded) so as to span between the lower ends of the pair of first side wall 18 and second side wall 20, and is also welded to the lower surface of the rear suspension side rail 12. ing.

  Here, as shown in FIGS. 2 and 3, the first flange portion 18 </ b> A of the first side wall portion 18 on the vehicle front side of the mounting bracket 16 described above includes, in a broad sense, a fragile portion or a weakened portion, and a low-rigidity portion. The notch 62 grasped as is formed. The formation range of the notch 62 is set so as to straddle the ridgeline 64 of the first flange portion 18A. As a result, the first side wall 18 disposed on the front side of the vehicle is reduced in rigidity at the position where the notch 62 is formed, and in the present embodiment, the outer side portion of the first side wall 18 along the broken line 66. 18B is slightly bent in a direction away from the second side wall 20.

  On the other hand, the above-described notch 62 is not formed in the second flange portion 20A of the second side wall portion 20 disposed on the rear side of the vehicle, but the second flange portion 20A is rather than the first flange portion 18A. It protrudes greatly in the longitudinal direction of the vehicle. The second flange portion 20A having a large overhanging range is welded to the reinforcing additional plate 60, so that the load input to the second side wall portion 20 of the mounting bracket 16 causes the second flange portion 20A and the reinforcing additional plate 60 to move. The configuration is such that it is transmitted to and supported by the rear suspension side rail 12 via.

(Operation and effect of this embodiment)
Next, the operation and effect of this embodiment will be described.

  First, a bush 28 attached to the distal end portion of the first arm portion 24B of the lower arm 24 is inserted between the first side wall portion 18 and the second side wall portion 20 of the mounting bracket 16, and the first side wall portion 18 and the second side wall portion 18 are inserted. The bolt insertion hole 36 of the portion 20 and the inner cylinder 30 are positioned coaxially. At this time, in this embodiment, the outer portion 18B of the first side wall portion 18 is slightly bent in the bracket opening direction with the fold line 66 as a fold, so that the bush 28 is interposed between the first side wall portion 18 and the second side wall portion 20. Easy to insert. After the bush 28 is inserted, the bolt 40 is fastened to the nut 42, and the outer side portion 18B of the first side wall portion 18 is deformed to the second side wall portion 20 side, and is in a fastening and fixed state.

  Here, in this embodiment, while setting the notch part 62 which divides the ridgeline 64 in the 1st flange part 18A of the 1st side wall part 18 of the attachment bracket 16, on the 2nd side wall part 20 side, the notch part 62 is provided. Rather than setting, rather, the second flange portion 20A protrudes larger than the first flange portion 18A, the first side wall portion 18 is stronger and more rigid with respect to the bushing axial load than the second side wall portion 20. Is low. That is, a difference in strength and a difference in rigidity are set between the first side wall 18 and the second side wall 20. For this reason, the deformation resistance of the first side wall portion 18 is lower than the deformation resistance of the second side wall portion 20, and the first side wall portion 18 can be easily deformed when the fastening torque of the bolt 40 is applied. Incidentally, the deformation resistance load of the present embodiment is reduced by about 45% as compared with the load without the configuration of the present embodiment.

  On the other hand, since the strength and rigidity of the second side wall portion 20 are relatively higher than those of the first side wall portion 18, the deformation strength and fatigue strength required when the vehicle travels after assembly is relatively high. It is secured (collateralized) on the second side wall 20 side.

  As described above, according to the suspension arm mounting portion structure according to the present embodiment, it is possible to achieve both the securing of deformation strength and fatigue strength during vehicle travel and the reduction of deformation resistance during vehicle assembly.

  Further, in the present embodiment, the first side wall portion 18 is configured in a flat plate shape, and the second side wall portion 20 is formed with the second flange portion 20A that protrudes larger than the first flange portion 18A. The rigidity of the side wall 18 in the bush axis direction can be adjusted by the thickness of the first side wall 18 and the notch range and area of the notch 62, and the rigidity of the second side wall 20 in the bush axis direction functions as a reinforcing means. The degree of reinforcement of the second flange portion 20A (for example, the size and welding strength of the second flange portion 20A) can be adjusted. As a result, according to the present embodiment, it is possible to relatively easily secure deformation strength / fatigue strength during vehicle travel and reduce deformation resistance during vehicle assembly.

[Supplementary explanation of the above embodiment]
In the above-described embodiment, the suspension arm mounting structure according to the present invention is applied to the rear suspension. However, the present invention is not limited to this, and the present invention may be applied to the front suspension. In other words, the suspension arm attachment structure according to the present invention is applicable to both the front suspension and the rear suspension.

  Moreover, in this embodiment mentioned above, in order to provide a strength difference and a rigidity difference positively, the notch part 62 was formed in the 1st side wall part 18 side, and the 2nd flange part 20A was set in the 2nd side wall part 20 side. However, the present invention is not limited to this, and no weak portion corresponding to the notch portion 62 is set on the first side wall portion 18 side, and the second flange portion 20 </ b> A having a high degree of reinforcement is set only on the second side wall portion 20. It may be. Even in this case, relative strength difference and rigidity difference can be given.

  Furthermore, in this embodiment mentioned above, although 2nd flange part 20A with many overhang | projection amounts was set as a reinforcement means, you may set not only this but another reinforcement means. For example, reinforcing means such as raising ribs may be set, or the projecting portion of the second flange portion 20A may be formed as a two-ply plate structure to increase the plate thickness.

It is the top view which drew the typical part of the attachment part structure of the suspension arm concerning this embodiment typically. It is the perspective view which looked at the mounting bracket from the 1st side wall part side. It is the perspective view which looked at the mounting bracket from the 2nd side wall part side. It is a perspective view showing the whole rear suspension composition concerning this embodiment.

Explanation of symbols

10 Rear suspension 18 First side wall (first support)
20 2nd side wall part (2nd support part)
20A Second flange (reinforcing means)
24 Lower arm (suspension arm)
24B 1st arm part 28 Bush 40 Bolt (fastener)
42 Nut (fastener)
50 1st member (1st support part)
52 2nd member (2nd support part)
54 Reinforcing members (reinforcing means)
62 Notch

Claims (2)

A bush provided at the arm tip of the suspension arm;
A first support portion and a second support portion supported on the vehicle body side and sandwiching the bush from both ends in the axial direction;
A fastener for fastening the first support portion and the second support portion in the bush axis direction with the bush sandwiched between the first support portion and the second support portion;
A suspension arm mounting portion structure comprising:
The bushing axial rigidity of the first support part is set lower than the bushing axial rigidity of the second support part,
A suspension arm attachment structure characterized by that. The first support portion is configured in a flat plate shape,
Reinforcing means for increasing the rigidity in the bush axis direction of the second support portion is set in the second support portion.
The suspension arm attachment structure according to claim 1, wherein:

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