Suspension arms

Abstract

To provide a suspension arm which can improve durability performance.SOLUTION: A lower arm 14 includes an arm body 20, a reinforcement member 30, and a resin molding part 40. The arm body 20 is composed of a metal material. The arm body 20 has a bottom wall 21, a pair of side walls 22 which project from both side edges of the bottom wall 21 and extend in an opposite manner, and a pair of flanges 23 projecting in a direction in which the pair of side walls 22 are separated from each end of the pair of side walls 22. The reinforcement member 30 is composed of a metal material. The reinforcement member 30 is welded to each of the flanges 23 in such a manner as to connect the pair of flanges 23. The resin molding part 40 is molded by a resin material by using the arm body 20 and the reinforcement member 30 as insert products. The resin molding part 40 has such a shape as to cover a weld part WP where the flange 23 and the reinforcement member 30 are welded to each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a suspension arm. [Background technology]

[0002] 2. Description of the Related Art Vehicles such as automobiles are provided with suspension arms that connect the vehicle body and wheels (for example, see Patent Document 1). The suspension arm described in Patent Document 1 has an arm body. The arm body is made of a metal plate. The arm body has a pair of side walls, a bottom wall, and a pair of flanges. The pair of side walls extend in the vehicle width direction in a manner facing each other. The bottom wall extends in a manner connecting one end (first end) of the pair of side walls in the vertical direction of the vehicle. The pair of flanges are provided on each of the pair of side walls. Each flange is provided at an end opposite the first end in the vertical direction of the vehicle. Each flange protrudes in a direction in which the pair of side walls move away from each other.

[0003] Patent Document 1 proposes providing a reinforcing member for reinforcement of a suspension arm. The reinforcing member is made of a fiber-reinforced resin material. The reinforcing member is provided in a manner that connects a pair of side walls, more specifically, a pair of flanges. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-107838 A Summary of the Invention [Problem to be solved by the invention]

[0005] The reinforcing member may be made of a metal plate. In this case, for example, the reinforcing member may be welded to each of the pair of flanges, resulting in a structure in which the pair of side walls (the pair of flanges) are connected by the reinforcing member.

[0006] Suspension arms are usually painted for protection. Therefore, if a reinforcement structure is adopted in which a reinforcing member is joined to the arm body by welding, the paint film at the welded part becomes easily peeled off due to the effect of an oxide film formed at the welded part. If a pebble from the road bounces up and hits the underside of the vehicle, causing the paint film to peel off, it will lead to a decrease in the durability of the suspension arm. [Means for solving the problem]

[0007] A suspension arm for solving the above problems comprises an arm body made of a metal material having a bottom wall, a pair of side walls protruding from both side edges of the bottom wall and extending in an opposing manner to each other, and a pair of flanges protruding from ends of each of the pair of side walls in the protruding direction in a direction in which the pair of side walls move away from each other; a reinforcing member made of a metal material and welded to each of the pair of flanges in a manner connecting the pair of flanges; and a resin molded portion that is molded from a resin material using the arm body and the reinforcing member as insert parts and has a shape covering the portion where the flanges and the reinforcing member are welded. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is an end view of a lower arm according to one embodiment of the suspension arm. [Diagram 2] 2 is a schematic diagram showing a schematic configuration of a suspension device of a vehicle to which the lower arm is applied. [Diagram 3] FIG. 2 is an exploded perspective view of an arm body and a reinforcing member that constitute the lower arm. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] 4 is a flowchart showing a manufacturing procedure of the lower arm. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a lower arm, which is one embodiment of a suspension arm, will be described. First, a suspension system to which the lower arm of this embodiment is applied will be described. As shown in Fig. 2, the suspension system 10 is provided between a vehicle body 11 and wheels 12. The suspension system 10 has a function of absorbing shocks transmitted from the road surface to the vehicle body 11 and a function of pressing the wheels 12 against the road surface.

[0010] The suspension device 10 has an upper arm 13 and a lower arm 14. The upper arm 13 and the lower arm 14 extend in the vehicle width direction in a manner that connects the wheel 12 and the vehicle body 11. The upper arm 13 and the lower arm 14 are provided at a distance from each other in the vertical direction of the vehicle 15. The lower arm 14 is disposed lower on the vehicle 15 than the upper arm 13. One end of the upper arm 13 and one end of the lower arm 14 are connected to the vehicle body 11. The other end of the upper arm 13 and the other end of the lower arm 14 are connected to the wheel 12.

[0011] The suspension system 10 has a suspension spring 16 which is a coil spring. The suspension spring 16 is installed between the vehicle body 11 and a lower arm 14. The suspension spring 16 is arranged such that the axis of the suspension spring 16 extends in the vertical direction. The lower end of the suspension spring 16 is attached to the lower arm 14.

[0012] A specific configuration of the lower arm 14 will be described below with reference to Figs. 1 to 6. Note that the X-axis, Y-axis, and Z-axis in each drawing are perpendicular to one another. In the following, the direction along the X-axis will be referred to as the X-axis direction, the direction along the Y-axis will be referred to as the Y-axis direction, and the direction along the Z-axis will be referred to as the Z-axis direction.

[0013] As shown in FIGS. 3 to 5, the lower arm 14 has an arm body 20, a reinforcing member 30, and a resin molded portion 40. As shown in FIG. <Arm body 20> The arm body 20 is made of a metal material. For example, a high tensile steel plate (SPFC, SPFH, etc.) is used as the metal material. The arm body 20 is formed by press working. The arm body 20 has a bottom wall 21, a pair of side walls 22, and a pair of flanges 23. The bottom wall 21, the pair of side walls 22, and the pair of flanges 23 form a hat-shaped cross section of the arm body 20 in a plane extending in the Y-axis direction and the Z-axis direction.

[0014] The bottom wall 21 extends in the X-axis direction and the Y-axis direction. When the lower arm 14 is attached to the vehicle 15 (see FIG. 2), the bottom wall 21 extends in the front-rear direction and the vehicle width direction of the vehicle 15.

[0015] The pair of side walls 22 protrude in the Z-axis direction from both side edges of the bottom wall 21. Each of the pair of side walls 22 extends in the X-axis direction and the Z-axis direction. The pair of side walls 22 are disposed facing each other with a gap in the Y-axis direction. In the arm body 20, the bottom wall 21 and the pair of side walls 22 extend in the X-axis direction in a manner that forms a U-shaped cross section that opens toward one side in the Z-axis direction (the upper side in FIG. 3).

[0016] The flanges 23 are provided on each of the pair of side walls 22. The flanges 23 are provided on the end of the side wall 22 opposite the bottom wall 21, i.e., on the end in the direction in which the side wall 22 protrudes from the bottom wall 21 (upward in FIG. 3). The flanges 23 are shaped to protrude in the direction in which the pair of side walls 22 move away from each other. The flanges 23 extend in the X-axis direction and the Y-axis direction. The flanges 23 extend along the ends of the side walls 22 over the entire length from one end to the other end of the side walls 22 in the X-axis direction.

[0017] As shown in Figs. 4 and 5, the arm body 20 has a first connecting portion 24, a spring portion 25, and a second connecting portion 26, which are aligned in this order from one side in the X-axis direction. <First connection part 24> The first connecting portion 24 is a portion that is attached to the vehicle body 11. In the first connecting portion 24, the pair of side walls 22 extend substantially parallel to each other. In the first connecting portion 24, the pair of flanges 23 extend substantially parallel to each other. Each side wall 22 in the first connecting portion 24 is provided with a first through hole 241 that penetrates in the Y-axis direction. The first connecting portion 24 is connected to the vehicle body 11 by utilizing the first through hole 241 in each side wall 22.

[0018] <Spring part 25> The spring portion 25 constitutes an intermediate portion of the arm body 20 in the X-axis direction. In the spring portion 25, the distance between the pair of side walls 22 in the Y-axis direction is larger than the distance between the pair of side walls 22 in the first connecting portion 24 and the distance between the pair of side walls 22 in the second connecting portion 26. In the spring portion 25, each side wall 22 and each flange 23 extends in a convex manner protruding in a direction in which the side walls 22 move away from each other. In the spring portion 25, each side wall 22 and each flange 23 extends in a convex manner having a gentle ridgeline with a low curvature.

[0019] A spring accommodating portion 251 is defined inside the spring portion 25. The spring accommodating portion 251 is defined by a pair of side walls 22 and a bottom wall 21. The spring accommodating portion 251 is configured to be able to accommodate an end of the suspension spring 16 (see FIG. 2). Specifically, the spring accommodating portion 251 includes a cylindrical space. When the lower arm 14 is attached to the vehicle 15, the end of the suspension spring 16 is accommodated inside the spring accommodating portion 251.

[0020] In the spring portion 25, a second through hole 252 penetrating in the Z-axis direction is provided in the bottom wall 21. <Reinforcing member 30> 3 to 5, the reinforcing member 30 is shaped to connect the ends (more specifically, the flanges 23) of the side walls 22 opposite the bottom wall 21 in the spring portion 25. The reinforcing member 30 is made of a metal material. As the metal material, a high-tensile steel plate (SPFC, SPFH, etc.) is used.

[0021] The reinforcing member 30 is joined (fixed) to the flange 23 of each side wall 22 by welding. For example, arc welding is used as the welding. The reinforcing member 30 extends in the X-axis direction and the Y-axis direction. Both ends (first end 31 and second end 32) of the reinforcing member 30 in the Y-axis direction extend along the opposing side walls 22 in a convex manner protruding in the direction in which the side walls 22 move away from each other. The first end 31 and the second end 32 of the reinforcing member 30 extend in a convex manner having a gentle ridgeline with a low curvature. The first end 31 and the second end 32 of the reinforcing member 30 are joined (fixed) to the upper surface 231 of the flange 23 of the arm body 20 through welding.

[0022] The reinforcing member 30 has a third through hole 33 penetrating in the Z-axis direction. The third through hole 33 is disposed in the center of the reinforcing member 30 in both the X-axis direction and the Y-axis direction. When the lower arm 14 is attached to the vehicle 15 (see FIG. 2), the suspension spring 16 is inserted through the third through hole 33.

[0023] <Second connection part 26> The second connecting portion 26 is a portion that is attached to the wheel 12. In the second connecting portion 26, the pair of side walls 22 extend substantially parallel to each other. In the second connecting portion 26, the pair of flanges 23 extend substantially parallel to each other. Each side wall 22 in the second connecting portion 26 is provided with a fourth through hole 261 that penetrates in the Y-axis direction. The second connecting portion 26 is connected to the wheel 12 by using the fourth through hole 261 in each side wall 22.

[0024] <Resin molding section 40> The resin molded portion 40 is made of a resin material. For example, a thermoplastic resin material (such as PP or PE) is used as the resin material. The resin molded portion 40 is molded by insert molding using the arm body 20 and the reinforcing member 30 as insert parts.

[0025] <Part 1 41> 1 and 5, the resin molded portion 40 has a first portion 41 that is shaped to cover the flange 23 from three directions in a tight contact state. The first portion 41 extends in the X-axis direction along the flange 23 with a U-shaped cross section. The first portion 41 extends over substantially the entire length of the flange 23 in the X-axis direction, excluding both ends in the X-axis direction.

[0026] In the first connecting portion 24 and the second connecting portion 26 of the lower arm 14, the first portion 41 of the resin molded portion 40 is shaped to cover in a tight contact state from three directions, including both sides of the flange 23 in the Z-axis direction and the tip end of the flange 23 in the Y-axis direction.

[0027] In the spring portion 25 of the lower arm 14, the flange 23 and the reinforcing member 30 are welded in a state where they are overlapped in the Z-axis direction. In the spring portion 25, the first portion 41 of the resin molded portion 40 is shaped to cover both sides of the overlapped flange 23 and the reinforcing member 30 in the Z-axis direction and the protruding end of the flange 23 in the Y-axis direction from three directions in a tight contact state. The portion of the spring portion 25 where the first portion 41 is formed includes the entire portion where the flange 23 and the reinforcing member 30 are welded (hereinafter, the welded portion WP). As shown in FIG. 1, the welded portion WP specifically includes a portion of the flange 23 on the side where the reinforcing member 30 is actually welded (upper side in FIG. 1) and a portion on the back side of the same portion (lower side in FIG. 1). In the spring portion 25, the first portion 41 extends in the X-axis direction along the end of the reinforcing member 30 in the Y-axis direction. In the spring portion 25, the first portion 41 extends over substantially the entire length in the X-axis direction of the portion where the reinforcing member 30 is disposed, excluding both ends in the X-axis direction of the reinforcing member 30.

[0028] <Second part 42> As shown in FIG. 1 and FIG. 4, the resin molded portion 40 has a second portion 42 that covers the outer surface of each side wall 22 and the outer surface of the bottom wall 21. The second portion 42 is shaped to cover the outer surface of each side wall 22, that is, the surface of one side wall 22 that is farther from the other side wall 22. The second portion 42 is shaped to cover the outer surface of the bottom wall 21 (the lower side of FIG. 1). The second portion 42 extends over substantially the entire length in the X-axis direction on the outer surfaces of each side wall 22 and the outer surface of the bottom wall 21, except for both ends in the X-axis direction of the pair of side walls 22 and both ends in the X-axis direction of the bottom wall 21. The surface shape of the second portion 42 is an uneven shape that can reduce air resistance. This reduces air resistance when the vehicle 15 is traveling. In this embodiment, an uneven shape is formed on the surface of the cavity of a mold device used to mold the resin molded portion 40. When the resin molded portion 40 is molded using this mold device, a concave-convex shape capable of reducing air resistance is transferred to the surface of the second portion 42 of the resin molded portion 40 .

[0029] <Part 3 43> As shown in Figs. 1 and 5, the resin molded part 40 has a third part 43 that covers the inner edge of the second through hole 252 of the arm main body 20. The third part 43 is shaped to cover both sides in the Z-axis direction of the inner edge of the second through hole 252 and the inner surface 253 of the fourth through hole 261 in a state of being in close contact from three directions. The third part 43 extends around the entire circumference of the inner edge of the second through hole 252 in a manner that forms a U-shaped cross section. The third part 43 extends along the inner edge of the second through hole 252 in the arm main body 20 in a manner that covers the inner edge of the second through hole 252 including the inner surface 253 of the second through hole 252.

[0030] A manufacturing procedure for the lower arm 14 will now be described with reference to FIG. [Formation process] 6, a "forming step" is first performed (step S1) in manufacturing the lower arm 14. In this step, the arm body 20 and the reinforcing member 30 (see FIG. 3) are formed by pressing.

[0031] [Welding process] After the "forming step," a "welding step" is performed (step S2 in FIG. 6). In this step, the reinforcing member 30 is joined (fixed) to the arm body 20 through welding. In this step, the first end 31 and the second end 32 of the reinforcing member 30 are welded to each of the pair of flanges 23 in a manner that connects the pair of flanges 23 to each other.

[0032] [Painting process] After the "welding step," a "painting step" is performed (step S3 in FIG. 6). In this step, the arm body 20 and the reinforcing member 30 are entirely painted with weather-resistant paint. In this embodiment, pretreatment for preventing the paint from peeling off from the welded portion WP (see FIG. 1), specifically, a treatment for removing an oxide film formed on the welded portion WP in the welding step, is not performed.

[0033] [Molding process] After the above-mentioned "painting process," a "molding process" is carried out (step S4). In this process, the resin molded portion 40 is molded by insert molding using the arm body 20 and the reinforcing member 30 as insert parts. Specifically, the painted arm body 20 and the reinforcing member 30 are inserted into a mold device, and the mold device is used to form the resin molded portion 40 in this state.

[0034] In this embodiment, the lower arm 14 having the arm body 20, the reinforcing member 30, and the resin molded portion 40 is integrally formed through a [forming process], a [welding process], a [painting process], and a [molding process].

[0035] <Action and effect> As described above, according to this embodiment, the following advantageous effects can be obtained. (1) The lower arm 14 includes an arm body 20, a reinforcing member 30, and a resin molded portion 40. The reinforcing member 30 is welded to each of a pair of flanges 23 of the lower arm 14 in a manner that connects the flanges 23 together. The resin molded portion 40 is shaped to cover the welded portion WP.

[0036] According to this embodiment, the welded portion WP in the lower arm 14 can be covered in close contact with the resin molded portion 40 made of a resin material. As a result, even if a small pebble hits the vicinity of the welded portion WP, the welded portion WP can be protected by the resin molded portion 40 covering the surface. This prevents the welded portion WP from being exposed to the outside due to damage to the portion covering the welded portion WP. This prevents deterioration of the welded portion WP, such as rusting of the welded portion WP, and improves the durability of the lower arm 14.

[0037] The lower arm 14 has a structure in which the surface of the coating is covered with the resin molded portion 40. This structure makes it difficult for the coating to peel off from the lower arm 14 (the arm body 20 and the reinforcing member 30) at the welded portion WP. Therefore, it is possible to omit pretreatment for preventing the coating of the welded portion WP from peeling off, more specifically, the treatment for removing the oxide film generated in the welding process.

[0038] (2) The resin molded portion 40 has a second portion 42 that covers the outer surfaces of each of the pair of side walls 22 and the outer surface of the bottom wall 21. The surface of the second portion 42 has an uneven shape that can reduce air resistance. According to this embodiment, the outer surface of the arm main body 20 is made of a resin material. Therefore, compared to when the outer surface of the arm main body 20 is made of a metal material, it is easier to apply a specific process to the outer surface of the lower arm 14 to form an uneven shape that can reduce air resistance.

[0039] (3) The arm body 20 constitutes the lower arm 14. The lower arm 14 is disposed close to the road surface and is therefore susceptible to the effects of pebbles bouncing off the road surface or water being splashed up on the road surface. According to this embodiment, the durability of the lower arm 14 can be improved.

[0040] (4) The arm body 20 has a spring accommodating section 251 defined by a pair of side walls 22 and a bottom wall 21. The spring accommodating section 251 is configured to be able to accommodate an end of the suspension spring 16. The arm body 20 has a second through hole 252 penetrating the bottom wall 21 in the spring accommodating section 251. The resin molded section 40 has a third portion 43 extending along the inner edge of the second through hole 252 in the arm body 20 in a manner covering the inner edge including the inner surface 253 of the second through hole 252. According to this embodiment, the lower arm 14 can be structured such that the arm body 20 and the resin molded section 40 engage with each other at the inner edge of the second through hole 252 of the arm body 20. Therefore, although the arm body 20 and the resin molded section 40 are formed of different materials, it is possible to prevent the relative positions of the arm body 20 and the resin molded section 40 from being unnecessarily misaligned.

[0041] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0042] The specific processing applied to the second portion 42 of the resin molded portion 40 is not limited to processing for forming a surface shape that reduces air resistance, and any processing can be applied. Examples of the specific processing include processing for forming the surface shape of the second portion 42 into a shape that imparts water repellency, processing for imparting stain resistance to the second portion 42, and the like.

[0043] One of the second portion 42 and the third portion 43 of the resin molded portion 40 may be omitted. Both the second portion 42 and the third portion 43 of the resin molded portion 40 may be omitted.

[0044] Of the first portion 41 constituting the resin molded portion 40, the portion formed in the first connecting portion 24 may be omitted, or the portion formed in the second connecting portion 26 may be omitted. The steps in manufacturing the lower arm 14 may be performed in the order of the forming process, welding process, molding process, and painting process. In this case, in the painting process, only the parts of the arm body 20 and the reinforcing member 30 that are not covered by the resin molded portion 40 are painted, so that the parts of the lower arm 14 that are made of metal can be protected by a paint film. Therefore, paint can be saved compared to painting the entire arm body 20 and the reinforcing member 30.

[0045] The lower arm 14 may be manufactured by performing the above-mentioned steps in the order of [forming process], [welding process], and [molding process]. In this case, in the [molding process], the resin molded portion 40 is molded into a shape that covers the entire arm body 20 and the reinforcing member 30, so that the entire lower arm 14 can be protected by the resin molded portion 40. In this case, the [painting process] can be omitted.

[0046] The suspension arm according to the above embodiment is not limited to being applied to the lower arm 14, but can also be applied to the upper arm 13. [Explanation of symbols]

[0047] 14 Lower Arm 16 Suspension spring 20 Arm body 21 Bottom wall 22 Side wall 23 Flange 25 Spring section 251 Spring housing 252 Second Through Hole 253 Inside 30 Reinforcement member 40 Resin molding section 41 Part 1 42 Part 2 43 Part 3 WP Welded Parts

Claims

1. an arm body made of a metal material, the arm body having a bottom wall, a pair of side walls protruding from both side edges of the bottom wall and extending in a manner facing each other, and a pair of flanges protruding from ends of each of the pair of side walls in the protruding direction in a direction in which the pair of side walls move away from each other; a reinforcing member made of a metal material and welded to each of the pair of flanges in a manner connecting the pair of flanges; a resin molded portion that is molded from a resin material using the arm body and the reinforcing member as insert parts and that has a shape that covers a portion where the flange and the reinforcing member are welded; A suspension arm comprising:

2. The resin molding portion is shaped to cover outer surfaces of the pair of side walls and an outer surface of the bottom wall.

2. The suspension arm according to claim 1.

3. The arm body constitutes a lower arm.

3. A suspension arm according to claim 1 or 2.

4. the arm body has a spring accommodating section defined by the pair of side walls and the bottom wall and configured to be able to accommodate an end of a suspension spring, and a through hole penetrating the bottom wall in the spring accommodating section, The resin molded portion has a portion that extends along an inner edge of the through hole in the arm body, the inner edge including the inner surface of the through hole, in a manner that covers the inner edge.

4. The suspension arm according to claim 3.

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