Lower arm for vehicle suspension

Abstract

This lower arm (1) for a vehicle suspension comprises a plate-shaped main body part (2). The main body part (2) includes: a first attachment part (3) that extends toward the inside in the vehicle width direction and has a front end attached to the vehicle body side; a second attachment part (4) that extends toward the inside in the vehicle width direction and has a front end attached to the vehicle body side further toward the rearward side of the vehicle body than the first attachment part (3); and a third attachment part (5) that extends toward the outside in the vehicle width direction and has a front end attached to the vehicle wheel side. A second portion (P2) between the first attachment part (3) and the second attachment part (4) is configured to be more fragile with respect to an input from the vehicle front surface in comparison to a first portion (P1) between the first attachment part (3) and the third attachment part (5).

Description

Automobile suspension lower arm

[0001] The present invention relates to a lower arm (transverse link) that constitutes a suspension for an automobile.

[0002] The vehicle front suspension body includes, for example, a pair of transverse links, a cross member connected to the ends of the pair of links extending from approximately the center of the transverse links, and a stiffening cover fixed to the rear side of the cross member (see Patent Document 1). The transverse link is also called a lower arm.

[0003] In this prior art, the stiffening cover is designed to be able to detach downward from the cross member or bend downward in the event of a collision at the center of the front of the vehicle, thereby absorbing the impact force (see paragraphs

[0016] to

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

[0004] Japanese Patent Application Laid-Open No. 2007-118664

[0005] However, the conventional front suspension body described above does not take into consideration a collision in which there is a small amount of overlap in the vehicle width direction between the front of the vehicle body and the object being hit (a so-called small overlap collision). Therefore, there is room for improvement to ensure sufficient impact absorption in small overlap collisions.

[0006] The problem to be solved by the present invention is to provide a lower arm that can further improve the absorption of impact during a collision.

[0007] 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 portion to be more vulnerable to inputs from the front of the vehicle than the first portion between the first and second mounting portions of the main body portion.

[0008] According to the present invention, it is possible to further improve the impact absorption during a collision.

[0009] FIG. 1 is a plan view showing an embodiment of a lower arm according to the present invention. FIG. 2 is a view taken along arrow A in FIG. 1. FIG. 3 is a view taken along arrow B in FIG. 1. FIG. 4A is a cross-sectional view of the main body taken along line IVA-IVA in FIG. 1. FIG. 4B is a cross-sectional view of the main body taken along line IVB-IVB in FIG. 1. FIG. 5 is a rear view showing an example of a third mounting portion and a ball joint of the lower arm shown in FIG. 1. FIG. 6A is a plan view (before deformation) illustrating how a lower arm according to an embodiment of the present invention deforms when a small overlap collision occurs. FIG. 6B is a plan view (after deformation) illustrating how a lower arm according to an embodiment of the present invention deforms when a small overlap collision occurs.

[0010] A lower arm 1 according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a plan view showing an example of the lower arm 1 according to this embodiment. Fig. 2 is a side view of the lower arm 1 as viewed from the direction of arrow A in Fig. 1. Fig. 3 is a side view of the lower arm 1 as viewed from the direction of arrow B in Fig. 2. Fig. 4(A) is a cross-sectional view taken along line IVA-IVA in Fig. 1, and Fig. 4(B) is a cross-sectional view taken along line IVB-IVB in Fig. 1. Fig. 5 is a rear view showing an example of a third mounting portion 5 and a ball joint 8 of the lower arm 1 according to this embodiment.

[0011] 1 to 5 show an example of a lower arm 1 in a front suspension provided on the left front wheel of an automobile. The lower arm 1 in this embodiment is a component that constitutes a front suspension such as, but not limited to, a MacPherson strut type. The lower arm 1 usually constitutes the lower part of the front suspension.

[0012] 1 to 3, the lower arm 1 includes a plate-shaped main body 2. The main body 2 is a metal plate made of a metal material such as iron. The plate-shaped main body 2 can be produced by, but is not limited to, pressing a metal plate having a substantially uniform thickness.

[0013] 1, the main body 2 in this embodiment has a generally L-shaped planar shape. The main body 2 includes a first mounting portion 3 extending inward in the vehicle width direction (to the right in the figure), a second mounting portion 4 extending inward in the vehicle width direction, and a third mounting portion 5 extending outward in the vehicle width direction (to the left in the figure).

[0014] The first mounting portion 3 is provided at the right front portion of the main body 2. A mounting hole 31 capable of fixing a front suspension bush 6 is formed at the tip of this first mounting portion 3, and as shown in Fig. 2, the tip of the first mounting portion 3 is attached to a vehicle body component 100 by the front suspension bush 6. The vehicle body component 100 is not particularly limited as long as it is a vehicle body component, and may be a front side member of an automobile body, a front suspension member, or the like.

[0015] The second mounting portion 4 is provided in the right rear portion of the main body 2. A mounting hole 41 capable of fixing a rear suspension bushing 7 is formed at the tip of this second mounting portion 4. The tip of the second mounting portion 4 is attached to the vehicle body component 100 by the rear suspension bushing 7, further rearward of the vehicle body than the first mounting portion 3.

[0016] The third mounting portion 5 is provided on the left front portion of the main body 2. A fixing plate portion 81 of the ball joint 8 is fixed to the tip (left end) of this third mounting portion 5 via a plurality of rivets 9. As shown in FIG. 5 , the fixing plate portion 81 in this embodiment is fixed to the underside of the third mounting portion 5. Note that the fixing plate portion 81 may also be fixed to the upper surface of the third mounting portion 5. The fixing plate portion 81 in this embodiment corresponds to an example of the "ball joint mounting portion" in the present invention. While the example in which the fixing plate portion 81 is fixed to the tip (left end) of the third mounting portion 5 with the rivets 9 has been described, this is not limiting and the fixing plate portion 81 may also be fixed with bolts.

[0017] 2, the tip of the third attachment portion 5 is attached to the wheel-side component 200 via this ball joint 8. The wheel-side component 200 is not particularly limited, and may be a component connected to the wheel, such as a knuckle or a hub.

[0018] As shown in FIG. 1 , the main body 2 has a first portion P 1 extending in the vehicle width direction (left-right direction in the drawing) between the first mounting portion 3 and the third mounting portion 5 . １ On the other hand, the main body 2 has a second portion P extending in the front-rear direction of the vehicle between the first mounting portion 3 and the second mounting portion 4. ２ The detailed structure will be described later, but in this lower arm 1, the first portion P １ is the second portion P of the main body 2 ２ Compared to the conventional type, the mechanical strength of the rear end is weaker against inputs from the front of the vehicle (external forces such as impacts from a collision).

[0019] 6A and 6B are plan views illustrating deformation of the lower arm 1 when a small overlap collision occurs, with Fig. 6A showing the state before the small overlap collision occurs and Fig. 6B showing the state after the small overlap collision occurs. Fig. 6A and Fig. 6B illustrate the lower arm 1 of a front suspension provided on the right front wheel (wheel 300) of an automobile.

[0020] The occupant protection performance in such a collision can be evaluated by a small overlap crash test. The small overlap crash test was conducted and published by the Insurance Institute for Highway Safety (IIHS) in the United States at the end of 2012. It is a type of offset frontal crash test in which 25% of the front of the vehicle on the driver's side is crashed into a barrier at a speed of 40 miles per hour (approximately 64 km / h). Generally, this crash test is conducted on a portion of the vehicle frame that is located outward in the vehicle width direction from the front side members.

[0021] As shown in FIG. 6A, the first portion P of the lower arm 1 on the wheel side in this embodiment １ is connected to a wheel 300 via wheel-side components 200 (see FIG. 2) such as a knuckle and a hub. The wheel 300 is housed in a front tire house of the vehicle body, and a side sill 400 of the vehicle body is disposed behind the front tire house. On the other hand, the second portion P ２ As described above, is connected to a vehicle body part 100 such as a front suspension member.

[0022] In this embodiment, when a small overlap collision occurs with a vehicle, a barrier (barrier) moves rearward while striking the end of the front bumper, and an impact is applied to the wheel 300. When an impact from the barrier acts on the wheel 300, an impact from the front also acts on the lower arm 1 supporting the wheel 300. As a result, the lower arm 1 of this embodiment has a relatively weak second portion P as shown in FIG. ２ begins to deform first, and the second part P ２ is deformed by bending backward due to the input from the front (front). １ Since the wheel 300 is in a state where it is barely deformed, the wheel 300 turns toward the rear left as indicated by the white arrow and comes into contact with the side sill 400 at the rear of the wheel well. In this way, the lower arm 1 of this embodiment can absorb the collision energy generated by a small overlap collision by sandwiching the wheel 300 between the object of collision and the side sill 400.

[0023] Also, the first part P １ is the second part P ２ Since the lower arm 1 is constructed to be stronger than the lower arm 300, it is less likely to deform even in the event of a small overlap collision, and the connection between the wheel 300 and the lower arm 1 can be maintained. Therefore, it is also possible to prevent the steering function from being lost.

[0024] Returning to Figure 1, the main body 2 in this embodiment specifically comprises a flat plate portion 20, a through hole 21, a working hole 22, multiple (two in this example) positioning holes 23a, 23b, a rib 24, a first recess 25, a second recess 26, a first flange 27 (see Figures 2 to 4(A)), a second flange 28 (see Figures 3 and 4(B)), and a narrow width portion 29.

[0025] As shown in Fig. 1, the flat plate portion 20 is formed in the center of the main body portion 2 and extends in the extension direction of the main body portion 2. The flat plate portion 20 of this embodiment has a first portion P １ From the left end of the third mounting portion 5 in ２ The second mounting portion 4 is formed continuously.

[0026] Second part P ２ 4B, a through hole 21 is formed in the flat plate portion 20. As shown in FIG. 4B, 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 up-down direction in the drawing). The through hole 21 allows the first portion P １ Compared to the second part P ２ Therefore, the second part P ２ This can promote deformation of the wheel, thereby improving impact absorption as described above and preventing loss of steering function. The through-hole 21 in this embodiment corresponds to an example of the "third weak portion" in the present invention.

[0027] 1, the through hole 21 has a first side 21a and a second side 21b. The first side 21a is adjacent to a right-end rib 24b (described later) of the rib 24, and is substantially 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 a left-rear end rib 24c (described later) of the rib 24, and is substantially parallel to the outline of the portion of the left-rear end rib 24c adjacent to the second side 21b. With such a through hole 21 having the first side 21a and the second side 21b, the area of ​​the through hole 21 can be increased compared to when a circular through hole is formed in the flat plate portion 20, and the first portion P １ than the second part P ２ can make the system vulnerable.

[0028] The flat plate portion 20 has a working hole 22 formed in front of the through hole 21. The working hole 22 in this embodiment is a through hole having a circular planar shape, and the first portion P １ to the second part P ２ This working hole 22 is used to pass a tool such as a wrench through when working on a part that is hidden by the lower arm 1 during assembly work on an automobile fitting line.

[0029] A positioning hole 23a is formed in the flat plate portion 20 behind the through hole 21. The positioning hole 23a in this embodiment is a through hole having a circular planar shape, and is located in the second portion P ２On the other hand, the positioning hole 23b is formed in the first portion P １ The positioning hole 23b has the same shape as the positioning hole 23a. These positioning holes 23a and 23b are through holes used to position the blank in a press when the metal plate that will become the main body 2 is press-formed.

[0030] In this embodiment, the first portion P １ Compared to the total area of ​​the holes in the second portion P ２ Therefore, the total area of ​​the holes in the first portion P １ than the second part P ２ In this embodiment, the total area S １ is the first portion P of the work hole 22 １ and the area of ​​the positioning hole 23b. ２ is the second portion P of the work hole 22 ２ and the area of ​​the positioning hole 23a.

[0031] A rib 24 having a predetermined width is formed around the periphery of the flat plate portion 20. This rib 24 is formed by the main body portion 2 bent so as to bulge 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 recessed downward relative to the rib 24 in the main body portion 2.

[0032] The ribs 24 include a front end rib 24a formed along the front edge of the main body 2, a right end rib 24b formed along the right edge of the main body 2, and a left rear end rib 24c formed along the left rear 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 integrally formed. Note that the front end rib 24a and the left rear end rib 24c in this embodiment correspond to an example of a "first tough portion" in the present invention.

[0033] 1 and 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. As shown in Fig. 1, the front end rib 24a includes a tip portion 241a that extends 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 tough portion" in the present invention.

[0034] The tip portion 241a overlaps with the fixing plate portion 81 in the vehicle width direction, thereby making it possible to construct a strong third mounting portion 5. This makes it possible to suppress deformation of the third mounting portion 5, improve impact absorption in the event of a small overlap collision, and also maintain steering function.

[0035] Furthermore, the width of the tip portion 241a increases toward the fixed plate portion 81 of the ball joint 8. Therefore, the tip portion 241a can make the third attachment portion 5 strong, and deformation of the third attachment portion 5 can be suppressed.

[0036] 1 and 2, a first recess 25 is formed in the front end rib 24a. The first recess 25 is formed in the first portion P １ The first portion P is provided closer to the first mounting portion 3 than the center of the first portion P. The first portion P is formed by recessing the front end rib 24a and extends in the front-rear direction of the vehicle. １ By providing the first recess 25 closer to the first mounting portion 3 than the center of the first portion P, when an input from the left or right direction of the vehicle occurs, such as in a side collision, the first portion P １ Since the second portion P can deform starting from the first recess 25, deformation of the third attachment portion 5 can be suppressed. ２ Even if a left-right input is received in a state where the first to third weak portions have already been deformed, the first portion P １ In a small overlap collision, the first portion P １It is desirable that the third mounting portion 5 does not deform as much as possible, but in the event of a side collision, it is desirable to suppress deformation of the third mounting portion 5 as much as possible, so the fourth weak portion is intentionally provided in the first tough portion. The first recess 25 in this embodiment corresponds to an example of the "fourth weak portion" in the present invention.

[0037] 2, the bottom surface of the first recess 25 has a substantially V-shaped cross section including a steeper slope than the second recess 26 (see FIG. 3), which will be described later. １ is the width W of the second recess 26 described later ２ (see FIG. 3). Therefore, when an input from the left side of the vehicle occurs, the first portion P １ The third mounting portion 5 is easily deformed starting from the first recess 25, and deformation of the third mounting portion 5 can be suppressed.

[0038] 1 and 3, the right end rib 24b extends in the longitudinal direction of the vehicle and is formed from the first mounting portion 3 to the second mounting portion 4. The right end rib 24b is formed at the second portion P ２ , the width narrows from the first mounting portion 3 to the second mounting portion 4.

[0039] The right end rib 24b is formed with a second recess 26. The second recess 26 is formed in the second portion P ２ The second recess 26 is formed by recessing the right end rib 24b and extends along the vehicle width direction. ２ By providing the second recess 26 in the right end rib 24b of the ２ Since the deformation of the second recess 26 can be promoted, the shock absorption can be improved and the loss of the steering function can be suppressed. The second recess 26 in the present embodiment corresponds to an example of the "second weak portion" in the present invention.

[0040] As shown in Fig. 3, the depth of the second recess 26 is shallower than the depth of the first recess 25, and the bottom surface of the second recess 26 includes a gentler slope than the first recess 25 (see Fig. 2). ２ is the width W of the first recess 25１ is larger compared to

[0041] 1, 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. Like the front end rib 24a, this left rear end rib 24c also includes a tip portion 241c that extends toward the third mounting portion 5 so as to overlap with the fixing plate portion 81 in the vehicle width direction. Like the tip portion 241a, the tip portion 241c also becomes wider as it approaches the fixing plate portion 81 of the ball joint 8. This tip portion 241c also corresponds to an example of the "rib of the first tough portion" in the present invention.

[0042] As shown in Figures 2 and 3, a first flange 27 is formed on the underside of the main body 2. This first flange 27 is formed by bending the front and right edges of the main body 2. As shown in Figures 4A and 4B, the tip of this 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.

[0043] As shown in FIGS. 2 and 4A, the front end 27a is １ and extends along the vehicle width direction. This front end portion 27a is formed from the first mounting portion 3 to the third mounting portion 5, and as shown in Figure 5, in this embodiment, extends to the edge of the third mounting portion 5 that faces the ball joint 8. The front end portion 27a in this embodiment corresponds to an example of the "second reinforcing portion" in the present invention.

[0044] The front end 27a of the first flange 27 extends to the edge of the third mounting portion 5, thereby making it possible to construct a strong third mounting portion 5. Therefore, in the event of a small overlap collision, deformation of the third mounting portion 5 can be suppressed, and steering function can be maintained.

[0045] As shown in FIGS. 3 and 4B, the right end portion 27b is connected to the second portion P ２ The right end 27b is provided on the right edge of the rear end 27a and extends in the front-rear direction of the vehicle. The right end 27b is formed from the first mounting portion 3 to the second mounting portion 4.

[0046] In this embodiment, the height H of the right end portion 27b １ is the height H of the front end portion 27a ２ It is lower than (H １ <H ２ ), the lower end of the front end 27a extends further downward than the lower end of the right end 27b. １ is the height H of the front end portion 27a ２ By making the second portion P ２ The first part P ２ Therefore, when a small overlap collision occurs, the second portion P ２ This can promote the transformation of the

[0047] 2 to 4, a second flange 28 is formed on the underside of the main body 2 so as to be parallel to the first flange 27. This second flange 28 is formed by bending the left rear edge of the main body 2. As shown in FIGS. 4A and 4B, the tip of this second flange 28 is also bent toward the inside of the main body 2.

[0048] This second flange 28 is formed from the second mounting portion 4 to the third mounting portion 5, and in this embodiment, as shown in Fig. 5, extends to the edge of the third mounting portion 5 that faces the ball joint 8. Since the second flange 28 extends to the edge of the third mounting portion 5, the third mounting portion 5 can be configured to be strong. The second flange 28 in this embodiment also corresponds to an example of the "second tough portion" in the present invention.

[0049] As shown in FIG. 1, the narrow portion 29 is ２ The narrow portion 29 is formed in the second portion P ２The narrow width portion 29 is located closer to the second mounting portion 4 than the center of the first mounting portion 3. In the narrow width portion 29, the width of the flat plate portion 20 narrows 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 closer to each other as they approach from the first mounting portion 3 toward the second mounting portion 4. Therefore, in the narrow width portion 29, the width of the main body portion 2 decreases from the first mounting portion 3 toward the second mounting portion 4. The narrow width portion 29 in this embodiment corresponds to an example of a "first weak portion" in the present invention.

[0050] Second part P ２ By providing the narrow portion 29 in the second portion P, when a small overlap collision occurs, ２ This can promote deformation of the vehicle, thereby improving the vehicle's ability to absorb a collision and also preventing the loss of steering function.

[0051] As described above, in the lower arm 1 of this embodiment, the second portion P ２ The first part P １ Since the second portion P is weaker than the first portion P when a small overlap collision occurs, ２ Specifically, in the case of the lower arm 1 according to the present embodiment, the narrow portion 29 (first weakened portion) and the second recess 26 (second weakened portion) are bent first during a small overlap collision, and the second portion P ２ Next, the vicinity of the through hole 21 (third weak portion) is bent, and the second portion P ２ In this way, the deformation of the second portion P ２ is preferentially deformed, so that the wheel 300 (see FIG. 6) can be pinched between the object of collision and the side sill 400. Therefore, the collision energy generated by a small overlap collision can be absorbed by the wheel 300 and the side sill 400, which suppresses deformation of the vehicle body and protects the occupants.

[0052] REFERENCE SIGNS LIST 1 lower arm 2 main body portion 20 flat plate portion 21 through hole 22 working hole 23a, 23b positioning holes 24 rib 24a front end rib 241a tip portion 24b right end rib 24c left rear end rib 241c tip portion 25 first recess 26 second recess 27 first flange 27a front end portion 27b right end portion 28 second flange 29 narrow width portion P １ ...First part P ２ ...second portion 3 to 5...first to third mounting portions 31, 41...mounting holes 51...fastening portion 6...front suspension bush 7...rear suspension bush 8...ball joint 81...fixing plate portion 9...rivet 100...vehicle body side component 200...wheel side component 300...wheel 400...side sill

Claims

1. A lower arm constituting an automobile suspension, wherein the lower arm includes a plate-shaped main body portion, the main body portion includes: a first attachment portion extending inward in the vehicle width direction and having a tip attached to the vehicle body side; a second attachment portion extending inward in the vehicle width direction and having a tip attached to the vehicle body side on the rear side of the vehicle body with respect to the first attachment portion; and a third attachment portion extending outward in the vehicle width direction and having a tip attached to the wheel side, wherein a second portion between the first attachment portion and the second attachment portion of the main body portion is configured to be more vulnerable to an input from the front of the vehicle than a first portion between the first attachment portion and the third attachment portion of the main body portion; the second portion includes: a first vulnerable portion where the width of the main body portion becomes narrower from the first attachment portion toward the second attachment portion; and a second vulnerable portion formed in the first vulnerable portion and extending in the vehicle width direction with the main body portion being recessed, wherein the second vulnerable portion is formed on the inner side in the vehicle width direction of the first vulnerable portion, and is a lower arm of an automobile suspension.

2. (Deleted)

3. (Deleted)

4. In the lower arm of an automobile suspension according to Claim 1, the second portion includes a third vulnerable portion formed by a through hole formed in the main body portion, and is a lower arm of an automobile suspension.

5. In the lower arm of an automobile suspension according to Claim 1 or 4, the first portion includes a first toughened portion formed by a rib where the main body portion bulges and extends in the vehicle width direction, and the rib of the first toughened portion extends toward the third attachment portion so as to overlap with an attachment portion of a ball joint attached to the third attachment portion in the vehicle width direction, and is a lower arm of an automobile suspension.

6. In the lower arm of an automobile suspension according to Claim 5, the rib of the first toughened portion has a wider width toward the attachment portion of the ball joint, and is a lower arm of an automobile suspension.

7. In the lower arm of an automobile suspension according to any one of Claims 1 and 4 to 6, the first portion includes a second toughened portion formed by a flange where an edge of the main body portion is bent and extends in the vehicle width direction to the third attachment portion, and is a lower arm of an automobile suspension.

8. In the lower arm of an automobile suspension according to any one of Claims 1 and 4 to 7, The lower arm of an automotive suspension, wherein the first part includes a fourth vulnerable part that is recessed on the side of the first attachment part from the center of the first part and extends in the vehicle longitudinal direction.