JP2001334813A - Aluminum suspension-arm and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum suspension-arm excellent in strength and its manufacturing method which makes cheaper manufacturing cost achievable. SOLUTION: In the method for manufacturing an aluminum suspension-arm with a joint part 20 prepared for attaching another part at least at an end of the suspension-arm body 10, while the arm 10 is produced by cutting an extruded hollow-shape material with required cross section to a predetermined length, a terminal member 2 is formed by cold forging T4-treated material in one body that has the joint part 20 and a connecting part 21 to connect the joint part 20 and the arm 10 together, then (an) end(s) of the arm 10 and the connecting member 21 of the terminal part 2 is fitted and the fitted portions 10 and 20 are joined to one body by friction welding and further aging-treated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum suspension arm used for a vehicle such as an automobile and a method for manufacturing the same.

[0002]

2. Description of the Related Art Aluminum components are widely used for various components of automobiles in place of iron-based materials in order to reduce the weight of vehicles, and aluminum forgings are also used for suspension arms. However, the suspension arm has a mounting portion for mounting other members of various shapes extending at one end or both ends of the arm body, and the shape is complicated. There was the disadvantage of being expensive.

Therefore, there has been proposed a method of manufacturing a suspension arm by extrusion molding with good production efficiency. For example,
A method in which the main body and the mounting portion are integrally formed by extrusion and then slice-cut to a required thickness, or the arm body and the mounting portion are separately extruded and each slice-cut product is subjected to TIG.
And a method of fusion welding with MIG or the like.

[0004]

However, in the former one-piece extruded product of the arm body and the mounting portion, the arm body becomes solid, which is contrary to the weight reduction and is limited to the extrudable shape. there were. In the latter case,
Although it is possible to reduce the weight by using a hollow extruded material for the arm body, problems such as a decrease in the material strength of the joint portion and thermal distortion occur due to the influence of heat during welding.

An object of the present invention is to provide an aluminum suspension arm which is lightweight and has excellent strength while reducing the manufacturing cost, and a method of manufacturing the same.

[0006]

In order to achieve the above object, an aluminum suspension arm according to the present invention has an aluminum body in which a mounting portion (20) for attaching another member is formed at least at one end of an arm body (10). The arm body (10) is made of an extruded hollow profile while the mounting part (20) is integrally formed with a connecting part (21) for connecting to the arm body (10). The mounting part (20) is assembled to the arm body (10) through the connecting part (21), and the assembled part is formed by friction stir welding.
The gist is that (0) and (20) are joined and integrated.

Further, the method of manufacturing an aluminum suspension arm according to the present invention is a method of manufacturing an aluminum suspension arm in which a mounting portion (20) for attaching another member is formed on at least one end of an arm body (10). The arm body (10) is manufactured by cutting an extruded hollow profile having a required cross-sectional shape into a required length, and the T4 treated material is cold forged to form the mounting portion (20) and the mounting portion. An end member (2) formed integrally with a connecting portion (21) for connecting the (20) to the arm body (10) is manufactured, and a connecting portion ( The basic point is that the end member (2) is assembled via 21), the assembled parts are joined and integrated by friction stir welding, and further subjected to aging treatment.

In the manufacturing method, a protruding portion (23) having a shape corresponding to the hollow portion (11) of the arm body (10) may be provided on the distal end side of the connecting portion (21) of the end member (2). It is preferable that these protrusions (2) are fitted into the hollow portion (11) of the arm body (10) to assemble these (10) and (20).

In the above-mentioned manufacturing method, the end member (2) may be formed by cutting an extruded material (5) having a cross-sectional shape similar to the end member (2) to a required length. 5 ′), and the forged material (5 ′) is preferably subjected to cold forging to be formed into a required shape.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An aluminum suspension arm (1) shown in FIG. 1 has a U-shaped mounting portion (20) at each end of a cylindrical arm body (10), and a stepped cylindrical connecting portion (20). 21) are joined together.

The suspension arm (1) is manufactured by the steps described in detail below.

The arm body (10) is manufactured by extruding a round pipe material having a predetermined thickness and cutting it into a predetermined length.

On the other hand, the end member (2) in which the mounting portion (20) and the connecting portion (21) are integrally formed is manufactured by extrusion and cold forging.

That is, as shown in FIG. 2, an extruded material (5) having a cross section similar to the shape of the end member (2) is manufactured, and the extruded material is cut into a predetermined thickness to form a rough shape. Produce the material (5 '). Further, it is necessary to perform a T4 treatment on the crude material (5 ′) before cold forging. By this heat treatment, strength can be improved, and deformation due to post-heat treatment after processing can be reduced. In addition, as a preferable T4 treatment condition, it is recommended that water cooling be performed after heating to 500 to 550 ° C.

Next, as shown in FIG. 3, the rough shaped material (5 ') is formed into an inner shape with a die (41) having a molding concave portion (40) corresponding to the outer shape of the end member (2). Cold forging with the corresponding punch (42) to form the final shape.
In forming by cold forging, a complicated shape that cannot be formed by extrusion can be manufactured, and an end member (2) having excellent dimensional accuracy and mechanical properties can be manufactured. In addition, machining can be performed in a shorter time than machining such as cutting, and the processing equipment can be simplified. If necessary, burrs generated during forging are trimmed by a known means such as a machining shot or a belt sander to finish the end member (2).

In this forging, the connecting portion (21) is formed in a columnar shape, and a large-diameter base end (22) and a small-diameter protruding portion (23) are formed on the distal end thereof to form a step. Molding. In the connecting portion (21), the cross-sectional diameter of the base end (22) is formed to be the same as the outer diameter of the arm body (10), and the cross-sectional diameter of the protruding portion (23) is set to the arm body ( 10) hollow part (1
It has the same dimensions as 1).

When the end member (2) is manufactured, the end member (2) can be manufactured only by cold forging without passing through a roughly extruded coarse material (5 '). Using is more efficient. Further, in order to form the rough shaped material (5 ') into an end member (2) having high dimensional accuracy by cold forging, a near net shape as close as possible to the end member (2) is used. Is preferred.

Next, as shown in FIGS. 4 and 5, connecting portions (2) of the end member (2) are provided at both ends of the arm body (10).
Insert the protruding part (23) of 1) (only one end is shown), insert it until the end face of the arm body (10) contacts the end face of the base end part (22) of the connecting part (21), and assemble them together . 4 and 5, (X) shows a butted portion between the arm body (10) and the connecting portion (20).

The connection between the arm body (10) and the end member (2) is made by connecting the projecting portion (23) on the distal end side of the connecting portion (21) to the hollow of the arm body (10) as in the present embodiment. By adopting a configuration that fits into the part (11), a more stable assembling state can be obtained than simple butting, and the workability in the next process is better. Also, the joint part is thicker than the arm body (10). As a result, the strength as a suspension arm is also improved. Further, by forming the connecting portion (21) in a stepped shape, the fitting depth to the arm body is regulated, and positioning in the length direction can be easily performed.

In the above-mentioned fitting structure, the hollow portion (11) of the arm body (10) and the projecting portion (23) of the connecting portion (21) are provided.
If the clearance between them is set as small as possible to press-fit the protruding portion (23) into the hollow portion (11), a more stable assembly state can be obtained. Also, it is preferable that the cross-sectional shape of the protruding portion (23) and the hollow portion (11) is formed in a non-circular shape such as a square or an ellipse, which facilitates positioning of the assembling position of the arm body in the circumferential direction.

Next, as shown in FIGS. 4 and 5, the assembled arm body (10) and the end member (2) are joined by friction stir welding. In the friction stir welding, for example, the rotor (31) is integrated with the large-diameter cylindrical rotor (31) and the axis (Q) of a shoulder (32) formed of a flat surface of the rotor (31). This is performed as follows using a joining tool (30) having a small-diameter pin-shaped probe (33) rotatably protruded.

First, the probe (33) is brought into contact with the outer peripheral surface of the butting portion (X) while rotating the rotor (31). Then, the vicinity of the butting portion (X) is softened and stirred by frictional heat generated by contact with the rotating probe (33), and the probe (33) is further pressed to be inserted deeply into the butting portion (X). In order to perform stronger bonding, it is preferable to insert the probe (33) until the tip of the probe (33) reaches the protrusion (23) of the connecting portion (21) beyond the peripheral wall of the arm portion main body (10) (FIG. 5). . Further, by inserting the shoulder portion (32) of the rotor (31) until it is embedded in the arm portion main body (10) and the connecting portion (21), more frictional heat can be generated, and the butt portion ( X) can be softened quickly.

After inserting the probe (33) to a predetermined depth, the welding tool (30) and the assembly are relatively rotated about the axis (P) of the arm body (10), and the welding tool (30) is rotated. )
Is moved in the circumferential direction of the butting portion (X). By this movement, the softening and stirring portion plastically flows so as to fill the passage groove of the welding tool (30), and then rapidly loses frictional heat and solidifies by cooling. This phenomenon is sequentially repeated by the movement of the joining tool (30), whereby the arm body (10) and the end member (2) are joined, in other words, the arm body (10) and the attachment section (20) are connected to each other. They are joined together via (21).

The above-described friction stir welding is a solid-phase welding, and can be performed at a lower temperature than fusion welding or brazing. for that reason,
Since there is little change in the material structure, and the change remains in a narrow range near the joint, there is little thermal effect such as a decrease in material strength or thermal distortion, and the joint strength is superior to that of fusion welding.

After joining by friction stir welding, aging treatment is performed to obtain more excellent strength as an arm. The aging condition is preferably 150 to 200 ° C. × 5 to 20 hours.

The aluminum used as the material of the suspension arm (1) is not particularly limited, but is JIS 6000-based Al-Si-Mg in that it has strength and corrosion resistance as an arm material and good formability. Based alloys, especially 6061 alloys, can be recommended.

Further, in the above-described embodiment, the U-shaped mounting portion is exemplified. However, the present invention does not limit the shape of the mounting portion, and the shape of another member such as a cylindrical vibration isolating bush may be used. And attachment means can be changed as appropriate. Further, the arm body is not limited to the pipe material having a circular cross section of the above-described embodiment, but may also include one having a rectangular cross section, an irregular shape, or the like.

[0028]

As described above, according to the present invention, there is provided an aluminum suspension arm in which an attachment portion for attaching another member is formed on at least one end of the arm body, and a method for manufacturing the same. While being manufactured as a lightweight extruded hollow material, the mounting part is manufactured as a cold forged material that can be formed into a desired shape that cannot be formed by extrusion, and the mounting part is connected to the arm body via a connecting part formed integrally with the mounting part. The suspension arm having a desired shape can be efficiently produced because the suspension arm is assembled by joining the assembled parts. Further, since the arm main body and the mounting portion are integrated by friction stir welding, the influence of heat upon joining is small, and the material strength and the joint strength are excellent. Further, since the end members constituting the mounting portion and the connecting portion are manufactured by cold forging a T4 treated material, the variation in strength is smaller than that of the extruded slice material, and post-processing such as cutting is almost unnecessary. Further, by performing an aging treatment after joining, further excellent strength can be obtained.

[0029] Also, on the tip side of the connecting portion of the end member,
A protrusion having a shape corresponding to the hollow portion of the arm body is formed, and the protrusion is fitted into the hollow portion of the arm body to assemble them, thereby facilitating positioning at the time of assembling and joining. Since the portion becomes thick, the joint strength is improved.

Further, the end member is manufactured by cutting an extruded material having a cross-sectional shape similar to that of the end member to a required length to produce a rough shape material, and subjecting the rough shape material to cold forging. By shaping into the required shape, the working time of cold forging can be shortened and the dimensional accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an intermediate step in an embodiment of an aluminum suspension arm and a method of manufacturing the same according to the present invention.

FIG. 2 is a perspective view showing a process of manufacturing a coarse material by cutting an extruded material.

FIG. 3 is a cross-sectional view showing a process of producing an end member by subjecting a crude material to cold forging.

FIG. 4 is a perspective view showing an assembled state of an arm body and an end member and a joining method by friction stir welding.

FIG. 5 is a front view showing an assembled state of the arm body and the end member and a joining method by friction stir welding, and partially showing a cross section taken along line VV of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Suspension arm 2 ... End member 5 ... Extruded material 5 '... Coarse shape material 10 ... Arm body 11 ... Hollow part 20 ... Mounting part 21 ... Connection part 23 ... Projection

Claims (4)

[Claims] At least one end of an arm body (10)
An aluminum suspension arm having a mounting portion (20) for mounting another member, wherein the arm body (10) is formed of an extruded hollow material, while the mounting portion (20) is formed of the arm body (10). A connecting portion (21) for connecting to the arm body (10) is integrally formed with the arm body (10) via the connecting portion (21); An aluminum suspension arm characterized in that these parts (10) and (20) are joined and integrated by friction stir welding at an assembly part. 2. At least one end of the arm body (10)
A method for manufacturing an aluminum suspension arm having a mounting portion (20) for mounting another member, wherein the arm body (10) is manufactured by cutting an extruded hollow profile having a required cross-sectional shape into a required length. On the other hand, by cold forging the T4 treated material, the mounting portion (20) and the mounting portion (2
0) to the arm body (10).
1) is manufactured integrally with the end member (2), and the end member (2) is attached to the end of the arm body (10) via the connecting portion (21). And (10) and (20) are joined and integrated by friction stir welding, and further subjected to aging treatment. 3. A protruding portion (23) having a shape corresponding to the hollow portion (11) of the arm body (10) is formed on the distal end side of the connecting portion (21) of the end member (2). The method for manufacturing an aluminum suspension arm according to claim 2, wherein the projection (2) is fitted into the hollow portion (11) of the arm body (10) to attach the projections (10) and (20). 4. The end member (2) is formed into a rough material (5 ′) by cutting an extruded material (5) having a cross-sectional shape similar to the end member (2) to a required length. The method for manufacturing an aluminum suspension arm according to claim 2 or 3, wherein the rough shaped material (5 ') is subjected to cold forging to be formed into a required shape.