Lower arm of automobile suspension

Abstract

The lower arm (1) of the automobile suspension is provided with a plate-shaped main body part (2). The main body section (2) comprises: a first attachment section (3) which extends inward in the vehicle width direction and which has a tip attached to the vehicle body side; a second attachment section (4) which extends inward in the vehicle width direction and which is attached to the vehicle body side at the tip thereof at a position further toward the rear side than the first attachment section (3); and a third attachment part (5) which extends outward in the vehicle width direction and which has a tip attached to the wheel side. A second portion (P2) between the first mounting portion (3) and the second mounting portion (4) is configured so as to be fragile with respect to an input from the front surface of the vehicle compared to a first portion (P1) between the first mounting portion (3) and the third mounting portion (5).

Description

Technical Field

[0001] The present invention relates to a lower arm (transverse link) constituting the suspension of a motor vehicle. Background Art

[0002] The front suspension body of the vehicle has, for example, a pair of transverse links, a cross beam connected to the ends of a pair of links extending from substantially the center of the transverse links, and a reinforcement cover fixed to the rear side of the cross beam (see Patent Document 1). The transverse link is also referred to as a lower arm.

[0003] In this prior art, the reinforcement cover is designed to absorb the collision force by being able to detach downward from the cross beam or being fixed to the cross beam in a manner that allows it to bend downward in the event of a collision at the center of the front of the vehicle (see paragraphs

[0016] to

[0019] , Figures 3 and 4 of Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2007-118664 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] However, the above-mentioned conventional front suspension body does not take into account a collision in which the amount of overlap between the front of the vehicle body and the collision object in the vehicle width direction is small (so-called small overlap collision). Therefore, there is room for improvement in order to make the impact absorption in a small overlap collision sufficient.

[0009] An object of the present invention is to provide a lower arm capable of further improving shock absorption during a collision.

[0010] Solutions for solving problems

[0011] The present invention solves the above problem by configuring the second portion between the first and third mounting portions of the plate-shaped main body to be weaker against input from the front of the vehicle than the first portion between the first and second mounting portions of the main body.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to further improve the shock absorption at the time of a collision. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a plan view showing an embodiment of a lower arm according to the present invention.

[0015] Figure 2yes Figure 1 A-direction view.

[0016] Figure 3 yes Figure 1 B view.

[0017] Figure 4A It is along the main body Figure 1 Cross-sectional view of the IVA-IVA line.

[0018] Figure 4B It is along the main body Figure 1 A cross-sectional view of the IVB-IVB line.

[0019] Figure 5 Yes means Figure 1 A rear view of an example of the third mounting portion and ball joint of the lower arm.

[0020] Fig. 6A It is a plan view showing how the lower arm according to the embodiment of the present invention deforms when a small overlap collision occurs (before deformation).

[0021] Figure 6B It is a plan view showing how the lower arm according to the embodiment of the present invention deforms when a small overlap collision occurs (after deformation). DETAILED DESCRIPTION

[0022] A lower arm 1 according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 It is a plan view showing an example of the lower arm 1 in the present embodiment. Figure 2 is from Figure 1 A side view of the lower arm 1 viewed in the direction of arrow A. Figure 3 is from Figure 2 A side view of the lower arm 1 viewed in the direction of arrow B. Figure 4A It is along Figure 1 The cross-sectional view of the IVA-IVA line in Figure 4B It is along Figure 1 Cross-sectional view along line IVB-IVB in FIG.

[0023] Figure 5 It is a rear view showing an example of the third mounting portion 5 and the ball joint 8 of the lower arm 1 in the present embodiment.

[0024] Figure 1 to Figure 5 The lower arm 1 provided in the front suspension of the left front wheel of the automobile is exemplified. The lower arm 1 in the present embodiment is not particularly limited, but is a component constituting a front suspension such as a MacPherson strut type. The lower arm 1 generally constitutes the lower portion of the front suspension.

[0025] like Figure 1 to Figure 3As shown, the lower arm 1 includes a plate-shaped main body 2. The main body 2 is a metal plate formed of a metal material such as iron. The plate-shaped main body 2 is not particularly limited, but can be produced by pressing a metal plate having a substantially uniform thickness as a whole.

[0026] like Figure 1 As shown, the main body 2 in this embodiment has a substantially L-shaped top view shape. The main body 2 includes a first mounting portion 3 extending toward the inner side in the vehicle width direction (the right side in the figure), a second mounting portion 4 extending toward the inner side in the vehicle width direction, and a third mounting portion 5 extending toward the outer side in the vehicle width direction (the left side in the figure).

[0027] The first mounting portion 3 is disposed at the right front portion of the main body 2. A mounting hole 31 is formed at the top end of the first mounting portion 3 to which the front suspension bushing 6 can be fixed. Figure 2 As shown, the top end of the first mounting portion 3 is mounted to a vehicle body component 100 by a front suspension bushing 6. The vehicle body component 100 is not particularly limited as long as it is a vehicle body component, and may be a front longitudinal member of an automobile body, a front suspension element, or the like.

[0028] The second mounting portion 4 is provided at the right rear portion of the main body 2. A mounting hole 41 to which the rear suspension bushing 7 can be fixed is formed at the top end of the second mounting portion 4. The top end of the second mounting portion 4 is mounted to the vehicle body side component 100 by the rear suspension bushing 7 at a position closer to the rear side of the vehicle body than the first mounting portion 3.

[0029] The third mounting portion 5 is provided at the left front portion of the main body 2. A fixing plate portion 81 of the ball joint 8 is fixed to the top end (left end) of the third mounting portion 5 by means of a plurality of rivets 9. Figure 5 As shown, the fixing plate portion 81 of this embodiment is fixed to the lower surface of the third mounting portion 5. In addition, the fixing plate portion 81 may also be fixed to the upper surface of the third mounting portion 5. In addition, the fixing plate portion 81 in this embodiment is equivalent to an example of the "mounting portion of the ball joint" in the present invention. The example of fixing the fixing plate portion 81 to the top end (left end) of the third mounting portion 5 using the rivet 9 is described, but it is not limited to this, and it may also be fixed by bolts.

[0030] like Figure 2 As shown, the tip of the third mounting portion 5 is mounted to the wheel-side component 200 via the ball joint 8. The wheel-side component 200 is not particularly limited, and may be a component connected to a wheel such as a knuckle or a hub.

[0031] like Figure 1As shown, the main body 2 has a first portion P1 extending in the vehicle width direction (left-right direction in the figure) between the first mounting portion 3 and the third mounting portion 5. On the other hand, the main body 2 has a second portion P2 extending in the vehicle front-rear direction between the first mounting portion 3 and the second mounting portion 4. The detailed structure will be discussed later, but in this lower arm 1, the first portion P1 of the main body 2 is constructed to be weak in mechanical strength against input from the front of the vehicle (force from the outside such as impact caused by a collision) compared to the second portion P2 of the main body 2.

[0032] FIG6 is a top view showing the deformation of the lower arm 1 when a small overlap collision occurs. Fig. 6A Indicates the state before a small overlap collision occurs. Figure 6B Indicates the state after a small overlap collision occurs. Fig. 6A and Figure 6B 2 , a lower arm 1 provided in a front suspension of a right front wheel (wheel 300 ) of an automobile is illustrated.

[0033] In addition, the passenger protection performance against such a collision can be evaluated by a small overlap collision test. The small overlap collision test is a test implemented and announced by the Insurance Institute for Highway Safety (IIHS) of the United States at the end of 2012. It is one of the frontal offset collision tests in which the front driver's seat side of the vehicle collides with an obstacle (barrier) at a speed of 40 miles per hour (about 64 kilometers). Generally, it is a collision test for the part of the vehicle body frame located outside the front longitudinal beam in the vehicle width direction.

[0034] like Fig. 6A As shown, the first portion P1 of the wheel side of the lower arm 1 in this embodiment is connected to the wheel side components 200 (see Figure 2 ) is connected to the wheel 300. The wheel 300 is housed in the front tire cover of the vehicle body, and the side beam 400 of the vehicle body is arranged behind the front tire cover. On the other hand, the second portion P2 of the lower arm 1 on the vehicle body side is connected to the vehicle body side component 100 such as the front suspension element as described above.

[0035] In this embodiment, when a small overlap collision occurs in the automobile, the obstacle (barrier) moves toward the rear of the vehicle while inputting to the end of the front bumper, and exerts an impact on the wheel 300. When the input from the obstacle acts on the wheel 300, the input from the front also acts on the lower arm 1 supporting the wheel 300. Figure 6BAs shown, the relatively fragile second portion P2 of the lower arm 1 of the present embodiment begins to deform first, and the second portion P2 is deformed in a manner of bending toward the rear due to the input from the front (front). At this time, the first portion P1 is in a state of being almost undeformed, so the wheel 300 turns toward the left rear as indicated by the hollow arrow and contacts the side beam 400 on the rear side of the tire cover. In this way, according to the lower arm 1 of the present embodiment, by sandwiching the wheel 300 between the collision object and the side beam 400, the collision energy generated by the small overlap collision can be absorbed.

[0036] Furthermore, since the first portion P1 is stronger than the second portion P2, even if a small overlap collision occurs, the first portion P1 is less likely to deform and the connection between the wheel 300 and the lower arm 1 can be maintained. Therefore, loss of the steering function can be suppressed.

[0037] return Figure 1 Specifically, the main body 2 in this embodiment includes a flat plate 20, a through hole 21, an operation hole 22, a plurality of (two in this example) positioning holes 23a, 23b, a rib 24, a first recess 25, a second recess 26, a first flange 27 (see Figure 2 to Figure 4A )、Second flange 28 (refer to Figure 3 and Figure 4B ), and a narrow width portion 29.

[0038] like Figure 1 As shown, the flat plate portion 20 is formed in the center of the main body 2 and extends along the extension direction of the main body 2. The flat plate portion 20 of this embodiment is continuously formed from the left end of the third mounting portion 5 in the first portion P1 to the front of the second mounting portion 4 in the second portion P2.

[0039] In the second portion P2, a through hole 21 is formed in the flat plate portion 20. Figure 4B As shown, the through hole 21 is a through hole that penetrates the flat plate portion 20 along the thickness direction of the flat plate portion 20 (the vertical direction in the figure). Due to the through hole 21, the second portion P2 can be made fragile compared to the first portion P1. Therefore, the deformation of the second portion P2 can be promoted, the impact absorption can be improved as described above, and the loss of the steering function can also be suppressed. In addition, the through hole 21 in this embodiment is equivalent to an example of the "third fragile portion" in the present invention.

[0040] like Figure 1As shown, the through hole 21 has a first side 21a and a second side 21b. The first side 21a is adjacent to the right end rib 24b (to be discussed later) of the rib 24 and is roughly parallel to the outline of the portion of the right end rib 24b adjacent to the first side 21a. Similarly, the second side 21b is adjacent to the left rear end rib 24c (to be discussed later) of the rib 24 and is roughly parallel to the outline of the portion of the left rear end rib 24c adjacent to the second side 21b. If the through hole 21 has such a first side 21a and a second side 21b, the area of ​​the through hole 21 can be increased compared to the case where a through hole in a perfect circular shape is formed in the flat plate portion 20, and the second portion P2 can be made more fragile than the first portion P1.

[0041] In the flat plate portion 20, a work hole 22 is formed in front of the through hole 21. The work hole 22 of the present embodiment is a through hole having a perfect circular shape in a plan view, and is formed from the first portion P1 to the second portion P2. The work hole 22 is used to allow a tool such as a wrench to penetrate when working on a component hidden by the lower arm 1 during assembly work on an automobile assembly line.

[0042] In the flat plate portion 20, a positioning hole 23a is formed behind the through hole 21. The positioning hole 23a of this embodiment is a through hole having a perfect circular shape in a plan view, and is formed in the second portion P2. On the other hand, the positioning hole 23b is formed in the first portion P1. The positioning hole 23b has the same shape as the positioning hole 23a. These positioning holes 23a and 23b are through holes used for positioning the blank in the press when the metal plate that becomes the main body portion 2 is subjected to a stamping process.

[0043] In the present embodiment, the total area of ​​the holes in the second part P2 is larger than the total area of ​​the holes in the first part P1. Therefore, the second part P2 can be made weaker than the first part P1. In addition, the total area S1 in the present embodiment is the sum of the area of ​​the portion of the working hole 22 located in the first part P1 and the area of ​​the positioning hole 23b. The total area S2 in the present embodiment is the sum of the area of ​​the portion of the working hole 22 located in the second part P2 and the area of ​​the positioning hole 23a.

[0044] A rib 24 having a predetermined width is formed around the flat plate portion 20. The rib 24 is formed by the main body portion 2 bent upward, and extends along the edge of the main body portion 2 except for the third mounting portion 5. Therefore, the flat plate portion 20 is relatively recessed downward in the main body portion 2 with respect to the rib 24.

[0045] The rib 24 includes a front end rib 24a formed along the front end edge of the main body 2, a right end rib 24b formed along the right end edge of the main body 2, and a left rear end rib 24c formed along the left rear end edge of the main body 2. Although not particularly limited, in this embodiment, the front end rib 24a, the right end rib 24b, and the left rear end rib 24c are formed integrally. In addition, the front end rib 24a and the left rear end rib 24c in this embodiment are equivalent to an example of the "first strengthening portion" in the present invention.

[0046] like Figure 1 and Figure 2 As shown in FIG. 2 , the front end rib 24a extends in the vehicle width direction and is formed from the first mounting portion 3 to the third mounting portion 5. Figure 1 As shown, the front end rib 24a includes a tip portion 241a extending toward the third mounting portion 5 so as to overlap the fixing plate portion 81 in the vehicle width direction. The tip portion 241a corresponds to an example of the "rib of the first reinforcement portion" in the present invention.

[0047] The top end portion 241a overlaps the fixing plate portion 81 in the vehicle width direction, thereby firmly forming the third mounting portion 5. Therefore, deformation of the third mounting portion 5 can be suppressed, shock absorption during a small overlap collision can be improved, and the steering function can be maintained.

[0048] In addition, the width of the tip portion 241a increases toward the fixing plate portion 81 of the ball joint 8. Therefore, the third mounting portion 5 can be firmly configured by the tip portion 241a, and deformation of the third mounting portion 5 can be suppressed.

[0049] In addition, if Figure 1 and Figure 2 As shown in FIG. 1 , the front end rib 24a is formed with a first recessed portion 25. The first recessed portion 25 is provided at a position closer to the first mounting portion 3 than the center of the first portion P1. The front end rib 24a is formed by being recessed and extends in the vehicle front-rear direction. By providing the first recessed portion 25 at a position closer to the first mounting portion 3 than the center of the first portion P1, when an input from the left and right direction of the vehicle is generated, such as in a side collision, the first portion P1 can be deformed starting from the first recessed portion 25, thereby suppressing the deformation of the third mounting portion 5. In particular, even when the first to third fragile portions of the second portion P2 are subjected to input from the left and right direction in a state where they are already deformed, the first portion P1 can be deformed starting from the first recessed portion 25 to absorb the collision energy, thereby suppressing the deformation of the third mounting portion 5. It is desirable that the first portion P1 is not deformed as much as possible in a small overlap collision, but in order to suppress the deformation of the third mounting portion 5 as much as possible in a side collision, the fourth fragile portion is intentionally provided in the first solid portion. The first recessed portion 25 in the present embodiment corresponds to an example of the “fourth fragile portion” in the present invention.

[0050] In addition, if Figure 2 As shown, the bottom surface of the first recess 25 has a second recess 26 (see Figure 3 ) has a substantially V-shaped cross-sectional shape with a steep slope. Also, the width W1 of the first recess 25 is greater than the width W2 of the second recess 26 discussed later (see Figure 3 Therefore, when an input is generated from the left side of the vehicle, the first portion P1 is easily deformed starting from the first recessed portion 25, and deformation of the third mounting portion 5 can be suppressed.

[0051] like Figure 1 and Figure 3 As shown, the right end rib 24b extends along the vehicle front-rear direction and is formed from the first mounting portion 3 to the second mounting portion 4. In the second portion P2, the width of the right end rib 24b narrows from the first mounting portion 3 toward the second mounting portion 4.

[0052] The second recess 26 is formed in the right end rib 24b. The second recess 26 is provided at a position closer to the second mounting portion 4 than the center of the second portion P2. The second recess 26 is formed by recessing the right end rib 24b and extends in the vehicle width direction. By providing the second recess 26 in the right end rib 24b of the second portion P2, the deformation of the second portion P2 can be promoted when a small overlap collision occurs, thereby improving the impact absorption and suppressing the loss of the steering function. The second recess 26 in this embodiment is equivalent to an example of the "second fragile portion" in the present invention.

[0053] like Figure 3 As shown, the depth of the second recessed portion 26 is shallower than that of the first recessed portion 25, and the bottom surface of the second recessed portion 26 includes a smaller area than the first recessed portion 25 (refer to Figure 2 ) A gentle slope. In addition, the width W2 of the second recess 26 is greater than the width W1 of the first recess 25.

[0054] like Figure 1 As shown in the figure, the left rear end rib 24c extends from the left front direction to the right rear direction, and is formed from the third mounting portion 5 to the second mounting portion 4. The left rear end rib 24c also includes a top end portion 241c extending toward the third mounting portion 5 in a manner overlapping with the fixing plate portion 81 in the vehicle width direction, similarly to the front end rib 24a. In addition, the top end portion 241c also has a width that increases as it approaches the fixing plate portion 81 of the ball joint 8, similarly to the top end portion 241a. The top end portion 241c is also equivalent to an example of the "rib of the first reinforcement portion" in the present invention.

[0055] like Figure 2 and Figure 3 As shown in FIG. 2 , a first flange 27 is formed on the lower surface of the main body 2. The first flange 27 is formed by bending the front end edge and the right end edge of the main body 2. Figure 4A and Figure 4B As shown, the tip of the first flange 27 is bent toward the inside of the main body 2. The first flange 27 has a front end 27a and a right end 27b.

[0056] like Figure 2 and Figure 4A As shown in FIG. 1 , the front end portion 27a is provided at the front end edge of the first portion P1 of the main body 2 and extends in the vehicle width direction. The front end portion 27a is formed from the first mounting portion 3 to the third mounting portion 5. Figure 5 As shown, in the present embodiment, the tip portion 27a extends to the end edge of the third mounting portion 5 that faces the ball joint 8. The tip portion 27a in the present embodiment corresponds to an example of the "second strengthening portion" in the present invention.

[0057] The third mounting portion 5 can be firmly formed by the front end portion 27a of the first flange 27 extending to the edge of the third mounting portion 5. Therefore, when a small overlap collision occurs, deformation of the third mounting portion 5 can be suppressed, and the steering function can be maintained.

[0058] like Figure 3 and Figure 4B As shown in FIG. 1 , the right end portion 27 b is provided at the right edge of the second portion P2 of the main body 2 and extends along the vehicle front-rear direction. The right end portion 27 b is formed from the first mounting portion 3 to the second mounting portion 4 .

[0059] In the present embodiment, the height H1 of the right end portion 27b is lower than the height H2 of the front end portion 27a (H1<H2), and the lower end of the front end portion 27a extends further downward relative to the lower end of the right end portion 27b. In this way, by making the height H1 of the right end portion 27b of the first flange 27 lower than the height H2 of the front end portion 27a, the second portion P2 is easier to bend in the thickness direction of the main body 2 than the first portion P2. Therefore, when a small overlap collision occurs, the deformation of the second portion P2 can be promoted.

[0060] like Figure 2 As shown in Fig. 4, a second flange 28 is formed on the lower surface of the main body 2 in parallel with the first flange 27. The second flange 28 is formed by bending the left rear end edge of the main body 2. Figure 4A and Figure 4B As shown, the tip of the second flange 28 is also bent toward the inside of the main body 2.

[0061] The second flange 28 is formed from the second mounting portion 4 to the third mounting portion 5. Figure 5As shown, in this embodiment, the second flange 28 extends to the end edge of the third mounting portion 5 that is opposite to the ball joint 8. By extending the second flange 28 to the end edge of the third mounting portion 5, the third mounting portion 5 can be firmly formed. The second flange 28 in this embodiment also corresponds to an example of the "second strengthening portion" in the present invention.

[0062] like Figure 1 As shown in the figure, the narrow width portion 29 is formed in the second portion P2 of the main body 2. The narrow width portion 29 is provided at a position closer to the second mounting portion 4 than the center of the second portion P2. In the narrow width portion 29, the width of the flat plate portion 20 becomes narrower from the first mounting portion 3 toward the second mounting portion 4, and the right end rib 24b and the left rear end rib 24c extend in a manner approaching each other as they approach the second mounting portion 4 from the first mounting portion 3. Therefore, in the narrow width portion 29, the width of the main body 2 becomes smaller from the first mounting portion 3 toward the second mounting portion 4. The narrow width portion 29 in this embodiment is equivalent to an example of the "first fragile portion" in the present invention.

[0063] By providing the narrow width portion 29 in the second portion P2 , deformation of the second portion P2 can be promoted when a small overlap collision occurs, thereby improving the collision absorption of the vehicle and suppressing the loss of the steering function.

[0064] As described above, in the lower arm 1 of the present embodiment, the second portion P2 is configured to be fragile compared to the first portion P1, so that when a small overlap collision occurs, the second portion P2 can be deformed first. Specifically, in the lower arm 1 of the present embodiment, when a small overlap collision occurs, the narrow width portion 29 (first fragile portion) and the second recessed portion 26 (second fragile portion) are first bent, and the second portion P2 is deformed. Then, the vicinity of the through hole 21 (third fragile portion) is bent, and the deformation of the second portion P2 is promoted. In this way, since the second portion P2 is deformed first, the wheel 300 (refer to FIG. 6 ) can be sandwiched between the collision object and the side beam 400. Therefore, the collision energy generated by the small overlap collision can be absorbed by the wheel 300 and the side beam 400, so that the deformation of the vehicle body can be suppressed and the passengers can be protected.

[0065] Description of Reference Numerals

[0066] 1. Lower arm; 2. Main body; 20. Flat plate; 21. Through hole; 22. Working hole; 23a, 23b, Positioning hole; 24. Rib; 24a, Front rib; 241a, Top end; 24b, Right rib; 24c, Left rear end rib; 241c, Top end; 25, First recess; 26, Second recess; 27, First flange; 27a, Front end; 27b, Right end; 28, Second flange; 29, Narrow width; P1, First part; P2, Second part; 3-5, First to Third mounting parts; 31, 41, Mounting hole; 51, Fastening part; 6, Front suspension bushing; 7, Rear suspension bushing; 8, Ball joint; 81, Fixing plate; 9, Rivet; 100, Vehicle body side parts; 200, Wheel side parts; 300, Wheel; 400, Side beam.

Claims

1. A lower arm of a vehicle suspension, which is a lower arm constituting a suspension of a vehicle, wherein: The lower arm includes a plate-shaped main body. The main body comprises: a first mounting portion extending toward the inner side in the vehicle width direction and having a top end mounted on the vehicle body side; a second mounting portion extending inward in the vehicle width direction and mounted on the vehicle body at a position on the rear side of the vehicle body relative to the first mounting portion; and The third mounting portion extends outward in the vehicle width direction, and the top end is mounted on the wheel side. The second portion of the main body between the first mounting portion and the second mounting portion is configured to be weaker against input from the front of the vehicle than the first portion of the main body between the first mounting portion and the third mounting portion.

2. The lower arm of the automobile suspension according to claim 1, wherein: The second portion includes a first fragile portion in which the width of the main body portion becomes narrower from the first mounting portion toward the second mounting portion.

3. The lower arm of the automobile suspension according to claim 2, wherein: The second portion includes a second fragile portion that is formed in the first fragile portion, is recessed in the main body portion, and extends in the vehicle width direction.

4. The lower arm of the automobile suspension according to any one of claims 1 to 3, wherein: The second portion includes a third fragile portion formed of a through hole formed in the main body portion.

5. The lower arm of the automobile suspension according to any one of claims 1 to 4, wherein: The first portion includes a first solid portion formed by a rib that is raised from the main body and extends in the vehicle width direction. The rib of the first reinforcement portion extends toward the third mounting portion so as to overlap with a mounting portion of a ball joint mounted to the third mounting portion in the vehicle width direction.

6. The lower arm of the automobile suspension according to claim 5, wherein: The width of the rib of the first strengthening portion increases toward the mounting portion of the ball joint.

7. The lower arm of the automobile suspension according to any one of claims 1 to 6, wherein: The first portion includes a second strengthening portion formed by a flange that is bent at an end edge of the main body portion and extends in the vehicle width direction to the third mounting portion.

8. The lower arm of the automobile suspension according to any one of claims 1 to 7, wherein: The first portion includes a fourth fragile portion that is recessed from the main body portion and extends in the vehicle front-rear direction at a position closer to the first mounting portion than the center of the first portion.

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