JP2002219918A - Suspension arm - Google Patents

Abstract

(57) [Summary] To provide a suspension arm capable of improving durability and reliability of a welded portion of a connecting member. A lower arm for connecting a vehicle body-side member and a wheel support member. A pin member 3 is attached to an end of the arm body 2. The end of the arm body 2 is stiffened and reinforced by a reinforcing plate 6. The reinforcing plate 6 is formed with a notch 8 having an engageable shape that can be engaged with the peripheral surface of the rod-shaped portion 3 a of the pin member 3. It is welded to the notch 8 of the reinforcing plate 6 with the peripheral surface of the rod-shaped portion 3a abutting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension arm for swingably connecting a vehicle body-side member and a wheel support member, and more particularly to a connection of a pin member for connecting a vehicle body-side member or a wheel support member. The present invention relates to a suspension arm characterized by a mounting structure between a member and an arm body.

[0002]

2. Description of the Related Art As a suspension arm, there is, for example, a lower arm. The lower arm is, for example, substantially L in plan view.
One end is connected to a knuckle portion (wheel supporting member) via a ball joint, and the other two ends are connected to a vehicle body-side member such as a suspension arm via a bush.

As shown in FIG. 10 which is a bottom view and FIG. 11 which is a cross-sectional view, one of the other ends of the lower arm has a pin member 51 (connecting member) attached to the end of the arm body 50 by welding. It is composed. The pin member 51 includes:
It comprises a cylindrical rod-shaped portion 51a fixed to the arm body 50 and a cylindrical pin body 51b attached to the bush. The pin main body 51b is inserted into the inner cylinder of the bush, in which the outer cylinder is fixed to the vehicle body-side member,
It is swingably connected to the vehicle body side member.

[0004] Conventionally, the rod-like portion 51a is attached to the arm main body 50 by, for example, Japanese Patent Application Laid-Open No. 9-2011.
It has a structure described in, for example, Japanese Patent Application Laid-Open No. 5 (1993) -2005. That is, referring to FIG. 10 and FIG. 11, a concave portion 52 having an arc-shaped cross section upwardly protruding from the lower surface of the end portion of the arm body 51 and capable of engaging the peripheral surface of the rod portion 51a is formed in the rod shape. It is formed along the extending direction of the portion 51a. The concave portion 52 of the arm body 50 is formed by press working. In a state where the rod portion 51a is engaged with the concave portion 52 from below, the space between the peripheral surface of the rod portion 51a and the arm body 50 is arc-welded along the extending direction of the rod portion 51a to perform the mounting. Has been done. Symbol W10 is the welded portion.

FIG. 11 shows an example in which a reinforcing plate 53 is provided, and the reinforcing plate 53 is arranged along the arm main body 50. In FIG. 10, the reinforcing plate 53 is omitted.

[0006]

In the lower arm, for example, a vertical load is repeatedly input to the pin main body 51b of the pin member 51. Therefore, the welding end 54 located near the input point P1 is provided. Stress tends to occur, and the stress also acts in the direction of separating the pin member 51 from the end of the arm body 50. Therefore, it is necessary to strengthen the welding end 54 from the viewpoint of durability.

The arc-shaped concave portion 52 of the arm body 50
End portions 52 of the concave portion 52 in order to form
a, 52b, that is, a radius is formed at a portion to be welded, and a welding portion W10 between the rod portion 51a and the arm main body 50 is formed.
Since welding into a wedge-shaped space, that is, penetration into a narrow place, is required, welding work must be performed slowly, and double welding must be performed to eliminate instability of penetration.

The present invention has been made in view of the above problems, and has as its object to provide a suspension arm capable of improving the durability and reliability of a welded portion of a connecting member.

[0009]

According to a first aspect of the present invention, there is provided a suspension arm for connecting a vehicle body-side member and a wheel supporting member, wherein the arm body includes A connecting member provided with a rod-shaped portion supported by the arm body and a connecting portion provided integrally with the rod-shaped portion and connected to the vehicle body-side member or the wheel supporting member;
A suspension plate attached to the arm body to reinforce or stiffen the arm body, and a suspension plate provided on the reinforcement plate and associated with a peripheral surface of the rod portion along the extending direction of the rod portion. And a notch of a shape that can be fitted, and the two are welded in a state where the rod-shaped portion peripheral surface is engaged with the notch of the reinforcing plate.

A second aspect of the present invention relates to a suspension arm for connecting a vehicle body-side member and a wheel support member, comprising an arm body, a rod-shaped portion supported by the arm body, and a rod-shaped portion. A connecting member that is integral with and protrudes from an end of the arm body and has a connecting portion that connects to the vehicle body-side member or the wheel support member; and a suspension arm having an end face of the end of the arm body. The arm has a closed cross-sectional shape, is integral with the rod-shaped portion and the connecting portion with respect to the boundary portion between the rod-shaped portion and the connecting portion, and faces the end surface of the end portion of the arm body and is on the outer diameter side of the end surface. It is characterized in that a flange portion that protrudes in the outer radial direction from the contour is provided, the flange portion is abutted against the end end surface of the arm body, and at least a part of the abutting portion of both is welded. It is.

According to a third aspect of the present invention, the entire periphery of the end face of the end of the arm body and the surface of the flange facing the end face abut against the structure described in the second aspect. In addition, the end of the arm body and the flange are welded over the entire circumference. Next, according to a fourth aspect of the present invention, at least the end portion of the arm main body is formed of a pair of plate-like members having a substantially U-shaped cross section with respect to the configuration described in the second or third aspect. The pair of plate-like members are faced to each other and connected to each other, so that the end surface of the end of the arm body has a closed cross-sectional shape having a substantially rectangular cross-section.

Next, a fifth aspect of the present invention is the reinforcing plate according to any one of the second to fourth aspects, wherein the reinforcing plate is attached to the arm body to reinforce or stiffen the arm body. And a notch formed in the reinforcing plate and capable of engaging with the peripheral surface of the rod along the extending direction of the rod, the notch of the reinforcing plate having the rod-like shape. The two are welded in a state where the peripheral surfaces are engaged.

Next, according to a sixth aspect of the present invention, in the configuration of the first or fifth aspect, the notch sandwiches the center of the cross section of the rod-shaped portion, such as a U-shape. The notch and the welded portion of the peripheral portion of the rod portion are formed at two positions sandwiching the center of the cross section of the rod portion. It is characterized by having.

According to a seventh aspect of the present invention, there is provided the arm body according to any one of the first, fifth, and sixth aspects, wherein a portion of the arm body for supporting the rod portion is closed. The reinforcing plate has a cross-sectional shape, and the reinforcing plate is disposed inside the closed cross-sectional shape. Next, the invention described in claim 8 is based on claim 1
A part of the peripheral surface of the rod-shaped portion is welded to the arm main body with respect to the configuration described in any one of claims to 7.

[0015]

According to the first aspect of the present invention, welding is performed in a state where the notch portion of the reinforcing plate and the peripheral surface of the rod portion are engaged, that is, the notch portion is brought into contact with the rod portion to perform welding. So you can
Stabilization of welding at the welded part improves welding reliability.
As a result, required durability can be secured without performing double welding.

According to the second aspect of the present invention, the end of the arm body is brought into contact with the flange of the connecting member and the two are welded, so that the connecting portion of the connecting member is connected to the connecting portion of the connecting member from the vehicle body or from the wheel. Even when a repeated load is applied, it is difficult for stress to concentrate on the welded portion, thereby improving durability. Next, according to the third aspect of the present invention, since the welding of the end of the arm body is the entire circumference welding, the welding end is present at the welding portion closest to the input point to the connecting portion of the connecting member. Since there is no need, stress concentration is less likely to occur at the welded portion, and the durability is further improved.

Next, if the invention according to claim 4 is adopted,
Since the closed cross-sectional shape of the end of the arm main body becomes a rectangular closed cross-section from a pair of members having a U-shaped cross section, it is necessary to form a protruding portion such as a flange shape at the end of the arm main body. Absent. As a result, the welded portion has a structure in which stress is less likely to be concentrated, and the durability is further improved. Next, when the invention according to claim 5 is adopted, welding can be performed in a state where the notch portion of the reinforcing plate is engaged with the peripheral surface of the rod portion, that is, the notch portion can be welded by abutting the rod portion. In addition, the fusion of the welded portion is stabilized, the welding reliability is improved, and the required durability is secured for the attachment portion of the connecting member without performing double welding.

Next, when the invention according to claim 6 is adopted,
With respect to the peripheral surface of the rod-shaped portion of the connecting member, two places on both sides are in contact with the notches, and the two contacting parts are located on both left and right sides of the cross-sectional center of the rod-shaped part. When viewed from the direction, since the welded part approaches the input point of the connected part and the welded part is arranged at the symmetrical position or substantially symmetrical position, the input from the rod-shaped part of the connecting member to the plate-shaped part is efficiently transmitted Is done. As a result, the strength, rigidity, and durability of the attachment portion of the connecting member are further improved.

According to the seventh aspect of the invention, since the reinforcing plate is fixed inside the shape of the closed end surface, the strength and rigidity of the end of the arm main body are improved, and the mounting portion of the connecting member is formed. The durability is further improved. Next, according to the invention according to claim 8, by welding a part of the rod-shaped portion to the arm body, the strength, rigidity and durability of the connecting member mounting portion are further improved.

[0020]

Next, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a lower arm will be described as an example of a suspension arm. Figure 1
FIG. 2 is a plan view showing the lower arm according to the present embodiment, and FIG.
Is a side view thereof, FIG. 3 is an exploded perspective view, and FIG. 6 is a front view showing attachment of the lower arm according to the present embodiment.

First, the structure will be described. The lower arm 1 includes an arm main body 2 and a pin member 3 constituting a connecting member. The arm body 2 includes an upper plate member 4 and a lower plate member 5 which are L-shaped in plan view. The upper plate member 4 and the lower plate member 5 are both flat plate portions 4a, 5a, and a pair of side plate portions 4b, 4c, 5b, 5c extending downward or upward from both sides in the width direction of the flat plate portions 4a, 5a, It is composed of That is, both the upper plate member 4 and the lower plate member 5 have a substantially U-shaped cross section.

4 and 5, which are sectional views, the upper portions of the side plates 5b and 5c of the lower plate 5 are inserted into the side plates 4b and 4c of the upper plate 4 from below. By fixing the two 4 and 5 by welding in the combined state, the arm main body 2 has a closed cross-sectional shape of a rectangular cross-section. Reference numeral W1 indicates a welded portion between the upper plate member 4 and the lower plate member 5. However, the upper plate member 4 and the lower plate member 5 may be connected by bolting or the like.

Here, it is sufficient that at least any one of the portions where the reinforcing plate 6 and the pin member 3 are attached has the above-mentioned closed cross-sectional shape. The end of the lower arm 1 on the wheel side constitutes a ball joint mounting portion 1a.
As shown in FIG. 1, the knuckle 11 is connected to a wheel supporting member via a ball joint 12. Code 13
Indicates a wheel. Reference numeral 14 denotes a shock absorber assembly.

The lower arm 1 has a vehicle body side end 1b,
c are provided at two locations in the vehicle longitudinal direction. An outer cylinder of a bush 7 whose axis is directed substantially in the front-rear direction of the vehicle body is fixed to one end 1b of the vehicle body side end, and is connected to a suspension member 10 constituting a vehicle body-side member via the bush 7. A pin member 3 is fixed to the other end 1c of the vehicle body side member (hereinafter, referred to as an end of the arm body 2), and a reinforcing plate 6 extending along the end of the arm body 2 is provided. Has been established.

As shown in FIG. 3, the pin member 3 has a rod-like portion 3a fixed and supported to the end of the arm body 2 via the reinforcing plate 6, and the rod-like portion 3a is integrated with the arm-like body 3a. 2. A pin body 3b extending substantially in the front-rear direction from the end of the body 2
And a flange 3c formed of an outward flange provided integrally with the rod 3a and the pin main body 3b at the boundary between the rod 3a and the pin main body 3b.

The reinforcing plate 6 extends in the end of the arm body 2 along the direction in which the arm body 2 extends, and both end surfaces in the width direction of the side plate 4b of the upper plate member 4, respectively.
The ends of the arm body 2 having a closed cross section are reinforced and stiffened by butt welding while being in contact with the inner surface of the arm 4c. Reference symbol W2 indicates a welded portion between the upper plate member 4 and the reinforcing plate 6. The upper plate member 4 and the reinforcing plate 6 may be connected by bolting or the like.

At the end of the reinforcing plate 6, a notch 8 is formed. The notch 8 has a U-shape in a plan view, and the rod-shaped portion 3 a of the pin-shaped portion 3 a of the pin member 3 is formed.
The rod-shaped portion 3a is formed into a shape that can engage with the peripheral surfaces on both sides of the center of the cross-section along the extending direction of the rod-shaped portion 3a. Reference numerals 8a and 8b denote engagement portions having shapes that can be engaged.

Here, the shape that can be engaged with the peripheral surface is as follows.
It refers to the shape along the peripheral surface. Note that not all of the engaging portions 8a and 8b need to be shaped to engage with the peripheral surface of the rod-shaped portion 3a. Then, the two peripheral surfaces of the rod-shaped portion 3a are engaged with the notch portion 8, that is, the abutting state is established, and the notch portion 8 and two contact portions of the rod-shaped portion 3a are connected by welding. The symbol W3 indicates the notch 8 and the rod 3a.
And a welded portion.

An elongated hole 4d extending in the direction in which the rod 3a extends is opened in a portion of the flat plate portion of the upper plate member 4 which is vertically opposed to the rod 3a. The peripheral surface of the rod-shaped portion 3a and the upper plate member 4 are welded. Reference numeral W4 indicates a welded portion between the upper plate member 4 and the rod-shaped portion 3a. Similarly, a long hole 5d extending along the extending direction of the rod portion 3a is opened in a portion of the flat plate portion of the lower plate member 5 vertically opposed to the rod portion 3a, and the rod shape is formed through the long hole 5d. The peripheral surface of the portion 3a and the lower plate member 5 are welded. Reference symbol W5 indicates a welded portion between the lower plate member 5 and the rod-shaped portion 3a.

The outer diameter of the flange 3c is set to be larger than the outer diameter of the end face of the end of the arm body 2, and the flange 3c is formed around the entire end face of the end of the arm body 2. And the size that can be opposed. The flange 3c and the end face of the end of the arm body 2 are abutted over the entire circumference, and the two 2 and 3c are connected by welding over the entire circumference. Reference numeral W6 indicates a welded portion between the end of the arm body 2 and the flange 3c.

The pin body 3b of the pin member 3 is
By being inserted into the inner cylinder of the bush (not shown) and fixing the outer cylinder of the bush to the suspension member 10, a load is input from the vehicle body side member to the pin body 3b through the bush. Symbol P indicates an input point. Next, the operation of the structure of the lower arm 1 having the above configuration will be described.

The rod portion 3a of the pin member 3 is welded to the notch 8 of the reinforcing plate 6 by butt welding, that is, the welding portion between the rod 3a and the notch 8 must be a narrow wedge-shaped space. Since there is no welding, the welding is performed in a space where the penetration is sufficiently possible, so that the penetration at the time of welding the rod portion 3a is stabilized, and the welding of the rod portion 3a to the reinforcing plate 6 is stabilized. Since the reinforcing plate 6 supporting the rod portion 3a is also welded to the arm body 2 by butt welding, welding when fixing the reinforcing plate 6 is also stable. For this reason, the durability for mounting the pin member 3 is improved.

Further, two places (two strips) on both sides of the peripheral surface of the rod-shaped portion 3a of the pin member 3 are provided with the engaging portions 8a of the notch portion 8,
8b, the two contact portions are located on the left and right sides of the cross-sectional center C of the rod-shaped portion 3a, so that the input point of the pin body 3b when viewed from the axial direction of the pin member 3 Since the welded portion is located at the symmetrical position or substantially symmetrical position as the welded portion approaches P, the rod-shaped portion 3
a to the reinforcing plate 6 is efficiently transmitted. As a result, the strength, rigidity, and durability of the mounting portion of the pin member 3 are further improved.

Further, since the reinforcing plate 6 is fixed inside the arm body 2 having the closed end surface shape, the strength and rigidity of the end itself of the arm body 2 are improved, and the durability of the mounting portion of the pin member 3 is further improved. Is improved. Further, by welding a part of the rod portion 3a to the end of the arm body 2, the strength and rigidity of the arm body 2 are further improved, and the durability of the mounting of the pin member 3 is further improved.

Further, by welding the flange 3c closer to the pin input point P than the rod 3a and the end of the arm body 2, the welding for attaching the pin member 3 can be made easier than the welding end of the conventional example. The position W6 of the portion on the pin body 3b side is closer to the pin input point P, and the stress on the welded portion W6 is:
Compared with the stress on the welded end of the conventional example, the welded portion W
The stress that directly separates the flange 3c and the end of the arm main body that are connected to each other at 6 is hardly generated, and therefore, stress is not easily concentrated on the welded portion W6. As a result, the durability of the attachment of the pin member 3 is further improved.

Further, the closed cross-sectional shape of the end of the arm body 2 is composed of a pair of plate members 4 and 5 having a U-shaped cross section. That is, since there is no portion forming a weld end, the welded portion connecting the arm body 2 and the flange portion 3c has a structure in which stress is less likely to be concentrated, and the durability is further improved. In particular, welding between the end of the arm body 2 and the flange 3c (reference W6)
Is a full circumference weld, it is not necessary to make the weld end closest to the input point P formed at the connection part of the connection member, so that stress concentration is less likely to occur at the weld W6, The durability is further improved.

Here, in the above embodiment, the case where the flange 3c and the end of the arm main body 2 are welded all around is described as an example. However, the flange 3c is always welded at predetermined intervals along the circumferential direction. It is not necessary to use full circumference welding. Also in this case, the stress concentration on the welded portion W6 between the flange 3c and the end of the arm body 2 is smaller than that of the conventional welded end.
Is more durable than the conventional example. When the flange 3c and the end of the arm body 2 are welded together, the rod 3a may be directly engaged with the arc-shaped recess of the arm body 2 and welded as in the conventional example. good. In this case, although the durability of mounting the pin member 3 is lower than that of the above-described embodiment, the durability of mounting the pin member 3 is higher than that of the conventional example.

In the above-described embodiment, the peripheral surface of the rod-shaped portion 3a that comes into contact with the notch 8 is the center of the cross-section C of the rod-shaped portion 3a.
However, as shown in FIG. 7, the width of the notch 8 may be set smaller than the diameter of the rod-shaped portion 3a so as not to be point-symmetric. . However,
The setting durability of the pin member 3 is better when the pin member 3 is set symmetrical as in the above embodiment. When not being point symmetric as shown in FIG. 7, it is not always necessary to incline the end surface of the notch portion 8 that comes into contact with the rod portion 3a so as to engage with the peripheral surface of the rod portion 3a. However, it is preferable to incline.

The notch 8 of the reinforcing plate 6 has a bar 3a.
When welding is performed, welding between the flange 3c and the end of the arm body 2 is not necessarily required, but the durability is improved by using this welding together. In the above embodiment,
Although the arm body 2 has a closed cross-sectional shape having a rectangular cross section by the upper plate member 4 and the lower plate member 5, the arm body 2 may have a shape opened to the lower side by omitting the lower plate member 5. Further, the lower plate member 5 may have a flat plate shape. However, in this case,
Since the welded end is formed when the end of the arm body 2 and the flange 3c are welded, the structure is disadvantageous, but the durability is improved as compared with the conventional example.

Although the cross section of the rod portion 3a is circular, it may be rectangular or hexagonal. Next, a second embodiment will be described with reference to FIGS. Note that parts and the like that are the same as those in the above embodiment are described with the same reference numerals. The basic configuration of this embodiment is the same as that of the first embodiment, but the shape of the notch 8 formed in the reinforcing plate 6 is different as shown in FIG.

That is, in the first embodiment, the notch 8 has a U-shape, and the cutout 8 is brought into contact with the peripheral surface of the rod 3a at two places across the center of the cross section of the rod 3a. However, in the present embodiment, as shown in FIGS. 8 and 9, the notch 8 is cut out in a rectangular shape, and the notch 8 has only one engaging portion with the peripheral surface of the rod-shaped portion 3 a. Things.

One of the peripheral surfaces of the bar-shaped portion 3a opposite to the engaging portion with the notch portion 8 across the center C of the cross section is welded to one side plate portion 4c of the upper plate member 4. Things. However, the rod portion 3a and the side plate portion 4c are welded by forming an elongated hole 4e in the side plate portion 4c along the extending direction of the rod portion 3a, and welding the two 3a and 4c through the elongated hole 4e. Improve reliability. In FIG. 9, a welded portion between the lower plate member 5 and the arm body 2 and the rod portion 3 a is omitted. Reference numeral W7 denotes a welded portion between the rod portion 3a and the side plate portion 4c.

Here, the side plate portions 4 on both sides of the upper plate member 4
It is also conceivable to form elongated holes facing the peripheral surface of the rod portion 3a in b and 4c, respectively, and to weld both side plate portions 4b and 4c of the rod portion 3a to the arm body 2 together. Not only is the width of the end of the arm body 2 limited by the rod-shaped portion 3a, but also the width of the arm body 2 is increased. In this regard, in the second embodiment, since one of the bar portions 3a is fixed to the arm body 2 via the reinforcing plate 6, the width of the end of the arm body 2 is not restricted by the bar portion 3a.

[Brief description of the drawings]

FIG. 1 is a top view showing a lower arm according to a first embodiment of the present invention.

FIG. 2 is a side view showing a lower arm according to the first embodiment of the present invention.

FIG. 3 is an exploded perspective view of a lower arm according to the first embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB in FIG. 1;

FIG. 5 is a sectional view taken along line AA in FIG.

FIG. 6 is a front (partial cross-sectional view) showing attachment of the lower arm according to the first embodiment of the present invention.

FIG. 7 is a view showing another relational state between the bar-shaped portion and the cutout portion.

FIG. 8 is a bottom view showing a relationship between an arm body and a pin member according to a second embodiment of the present invention.

FIG. 9 is a sectional view illustrating a relationship between an arm body and a pin member according to a second embodiment of the present invention.

FIG. 10 is a bottom view showing a relationship between a conventional arm body and a pin member.

FIG. 11 is a cross-sectional view showing a relationship between a conventional arm body and a pin member.

[Explanation of symbols]

 P Input point C Cross-sectional center of rod-shaped part W1-W7 Welded part 1 Lower arm (suspension arm) 2 Arm body 3 Pin member (connecting member) 3a Rod-shaped part 3b Pin body (connecting part) 3c Flange part 4 Upper plate member 4a Flat plate part 4b, 4c Side plate portion 4d Long hole 4e Long hole 5 Lower plate member 5a Flat plate portion 5b, 5c Side plate portion 5d Long hole 6 Reinforcement plate 8 Notch portion 8a, 8b Engaging portion 10 Suspension member (vehicle side member) 11 Knuckle ( Wheel support member) 12 Ball joint

Claims (8)

[Claims] 1. A suspension arm for connecting a vehicle body-side member and a wheel support member, comprising: an arm body; a rod-shaped portion supported by the arm body; A connecting member having a connecting portion connected to the wheel supporting member, a reinforcing plate attached to the arm body for reinforcing or stiffening the arm body, and the rod-shaped member provided on the reinforcing plate. A notch portion that can be engaged with the peripheral surface of the rod portion along the extending direction of the portion, and the rod-shaped portion peripheral surface is engaged with the notch portion of the reinforcing plate. A suspension arm characterized by welding. 2. A suspension arm for connecting a vehicle body-side member and a wheel supporting member, comprising: an arm main body; a rod-shaped portion supported by the arm main body; A connecting member protruding from an end portion and having a connecting portion connected to the vehicle body-side member or the wheel supporting member; and a rod-shaped portion having an end surface of an end portion of the arm body having a closed cross-sectional shape. A flange integrated with the rod-shaped portion and the connecting portion with respect to a boundary portion between the arm body and the connecting portion, facing the end surface of the end portion of the arm main body, and protruding in an outer diameter direction from an outer diameter side profile of the end surface. A suspension arm, wherein a flange portion is provided to abut against an end face of the arm body, and at least a part of the abutting portion is welded. 3. The entire circumference of an end face of the end of the arm body and the surface of the flange facing the end face can be abutted. The suspension arm according to claim 2, wherein the suspension arm is welded over the circumference. 4. At least an end portion of the arm main body is composed of a pair of plate-like members having a substantially U-shaped cross section, and the pair of plate-like members are connected to face each other to form an end of the arm main body. The suspension arm according to claim 2 or 3, wherein an end face of the portion has a closed cross section having a substantially rectangular cross section. 5. A reinforcing plate attached to the arm body to reinforce or stiffen the arm body, and is provided on the reinforcing plate and engages with a peripheral surface of the bar along the extending direction of the bar. And a notch part of a possible shape, wherein both are welded in a state where the rod-shaped part peripheral surface is engaged with the notch part of the reinforcing plate. A suspension arm according to any of the above. 6. The notch has a shape that can be engaged with the peripheral surface of the rod at two locations with the center of the cross section of the rod being interposed therebetween. The suspension arm according to claim 1 or 5, wherein the welded portion is located at two positions with respect to the center of the cross section of the rod-shaped portion. 7. A portion of the arm body supporting the rod-shaped portion has a closed cross-sectional shape, and the reinforcing plate is disposed inside the closed cross-sectional shape. The suspension arm according to any one of claims 5 and 6. 8. The arm member according to claim 1, wherein a part of a peripheral surface of the rod portion is welded to the arm body.
The suspension arm according to any of the above.