JPH07315025A - Arm for suspension and its manufacture - Google Patents

Abstract

PURPOSE:To provide the arm for suspension and its manufacture where the arm for suspension is formed out of pipe material into a hollow structure for lightening its weight, and it is prevented from being degraded in strength. CONSTITUTION:The arm for suspension is formed out of pipe material wherein the pipe material is bent roughly in an L shape, its bent section 15 is made large in shape, a bearing boss mounting seat 13 is formed at the outside surface of the bent section 15, and concurrently a suspension member installation section 11 and a wheel support member installation section 12 are formed at both end sections of the bent section.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A suspension arm for an independent suspension type automobile has an upper arm 2 at both ends of a suspension member 1 on the vehicle body frame side, as shown in FIG.
And the lower arm 3 are attached so as to be swingable in the vertical direction.
Can be installed. Reference numeral 5 indicates a suspension.

The above-mentioned arm is a conventional cast or forged product made of iron, or a sheet metal 6, 6 having the same thickness as shown in the cross section in FIG. 6 is cut into an arm shape in advance and then formed into a curved cross section by pressing. Generally, a sheet metal member is generally used in which the plate members 6 and 6 are aligned together and the flange portions 6a and 6a on the periphery thereof are welded and integrated.

[0004]

However, in the above-mentioned casting or forging, the weight is large because of the non-void structure,
This causes an increase in vehicle weight. Further, a sheet metal product requires a lot of welding steps, so that the productivity is low and the cost is not only high, but also stress concentrates on a portion close to the welded portion (a, a portions in FIG. 6), and strength is increased. There were problems, such as weaknesses.

In view of this, the present invention provides a suspension arm which is formed of a pipe material and can have a hollow structure for weight reduction, has a small number of processing steps, and has no weak point in strength, and a method for manufacturing the same. The purpose is to do.

[0006]

As a means for solving the problems of the above-mentioned conventional techniques, the present invention is made of a pipe material and is bent in a substantially doglegged shape, and the bent portion is formed enormously and bent. The suspension arm is characterized in that the bearing boss mounting seat is formed on the outer surface of the section, and the suspension member mounting section and the wheel supporting member mounting section are formed at both ends. Bend to the bending angle and hydraulically work with a bulge mold that has the shape of the final shape of the arm to bulge the bearing boss mounting seat on the outer surface side of the bent part, then flatten both ends after bulging. A suspension arm mounting portion and a wheel support member mounting portion are formed.

[0007]

Since the suspension arm has a hollow structure made of a pipe material, the suspension arm is lightweight, and the intermediate portion including the bearing boss mounting seat is enlarged to have a substantially large diameter. Even if the thickness is thin, the section modulus will increase, and the work hardening will add to increase the strength. As a result, there will be no decrease in strength even with a predetermined arm shape, and it will be possible to make a suspension arm that is lightweight but has high strength. it can.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 1 is a front view showing an embodiment in which the present invention is applied to a lower arm 10 of an automobile suspension, FIG. 2 is a top view of FIG. 1, and FIG. 3 is a side view of the same.

In these drawings, 11 is a suspension member mounting portion for axially mounting the suspension member 1 on an end portion, 12 is a wheel supporting member mounting portion for axially mounting a wheel supporting member 4, and 13 is a suspension member. 1 is a suspension member mounting portion for mounting a bearing boss 14 for pivotally mounting on the other portion of FIG. 1, and the inside is a chain line b, c, d in FIG.
As shown in (3), the pipe material is hollow and the middle portion is bent in a substantially V shape, and the bent portion 15 has the largest diameter. The bearing boss mounting seat 13 is formed on the outer surface of the bent portion 15 so as to bulge. The end surface of the bearing boss mounting seat 13 has a shape suitable for the base 14a integrally provided on the outer periphery of the cylindrical bearing boss 14 to abut and to be fixed by welding 16, for example, a flat shape.

The mounting portions 11 and 12 are formed so as to form a bearing portion by punching a simple hole or by press-fitting or welding a bearing member which is a separate component.

In forming the lower arm 10, as shown in FIGS. 4 (A) to 4 (C), both ends of the pipe material 17 (FIG. 4 (A)) cut into a predetermined length are drawn into tapered shapes. (FIG. 4 (B)) Next, after gently bending the pipe material 17 to a predetermined angle, the pipe material 17 is housed in a bulge mold having a mold for obtaining the final form of the lower arm 10 and clamped. The pressure liquid is press-fitted from one end or both ends of the bearing boss mounting seat 13 (the outer surface of the bent portion 15) to bulge (FIG. 4C).

After the pipe material 17 is taken out from the bulge mold, the end surface of the bearing boss mounting seat 13 is pressed as necessary to form a shape suitable for mounting the bearing boss 14, and both ends of the pipe material 17 are flat. Mounted parts 11, 12
The holes 11a and 12a required as the above are bored, and a bearing member is fitted into these to form a bearing portion, and the bearing boss 14 is welded to the bearing boss mounting seat 13 to form the final form.

In the above process, the pipe material 17 may be bent at the same time as the bearing boss mounting seat 13 is bent by a bulge type, or may be bent separately. Of course, an upper arm may be formed similarly to the lower arm 10,
The orientation of the mounting portions 11 and 12 and the orientation of the bearing boss 14 are appropriately selected according to the vehicle type.

[0015]

As described above, according to the present invention, since the arm used for the suspension of the automobile is formed by the pipe material, the weight can be remarkably reduced, but the intermediate portion is enlarged and the section modulus is increased. Since it has become larger, the work hardening accompanying the expansion has also been added to increase the strength,
Even if the wall thickness of the portion is reduced, the strength as a whole is not impaired, and a lightweight and high-strength arm can be obtained. Further, since the welding process is required only for mounting the bearing boss, it does not take time to manufacture, there is no material deterioration due to welding, and it is suitable for mass production and can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a suspension arm according to the present invention.

FIG. 2 is a top view of FIG.

FIG. 3 is a right side view of FIG.

4A to 4C are explanatory views showing an example of a manufacturing process of the suspension arm of FIG.

FIG. 5 is a perspective view showing a suspension portion of an automobile.

FIG. 6 is a sectional view of a conventional hollow suspension arm.

[Explanation of symbols]

1 Suspension Member 2 Upper Arm 3,10 Lower Arm 11 Suspension Member Attachment Part 12 Wheel Support Member Attachment Part 13 Bearing Boss Attachment Seat as Suspension Member Attachment Part 14 Bearing Boss 15 Bent Part 17 Pipe Material

Claims (2)

[Claims] 1. A pipe material, which is bent into a substantially V shape,
A suspension arm characterized in that a large number of bent portions are formed, a bearing boss mounting seat is formed on an outer surface of the bent portion, and a suspension member mounting portion and a wheel support member mounting portion are formed at both end portions. 2. A pipe boss is attached to the outer surface of the bent portion by drawing both ends of the pipe material, bending the pipe material to a predetermined bending angle, and hydraulically working with a bulge die having a die of the final shape of the arm. A method for manufacturing a suspension arm, comprising forming a suspension member mounting portion and a wheel support member mounting portion by bulging a seat and flattening both ends after bulging.