JPH0129609B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for forming a rim of an automobile wheel, and particularly to a method for forming a rim that enables forming with a small axial load.

[Prior Art] Conventional rim forming involves forming a cylindrical rim material R by winding a flat rim material into a cylindrical shape and welding the butt portions, as shown in the steps shown in Fig. 1.
Either press the entire circumference in the axial direction with a pair of flaring presses to spread out both ends, or press the entire circumference in the axial direction with a flairing press and lower the upper roll. The parts B and C in Figure 1 are processed and formed at the same time. For this reason, it was necessary to spread the entire rim at the same time, which required high pressure in the flaring press and upper roll.
As time went on, equipment became larger, more complex, and more costly.

In order to reduce this axial compressive force, British Patent No. 487820 discloses that a cylindrical rim material is compressed in the axial direction by a pair of mutually inclined shaping rolls, and , this axial compressive force is applied. A technique is disclosed in which a rim material portion is pressed from the outer peripheral side with a radial pressing roll. In such a forming method, when a portion of the rim material is hollowed out by a radial pressure roll, as the formed hollow becomes progressively deeper, the axial load changes into a bending force at the hollow area. Since it helps deform the rim material, less axial clamping pressure is required, which simplifies and downsizes the molding equipment.
The energy required for molding can be reduced.

[Problems to be Solved by the Invention] However, the method disclosed in the specification of British Patent No. 487820 still has the following problems. In other words, since the pressing position by the radial pressing roll and the clamping position by the pair of shaping rolls are aligned in the circumferential direction of the cylindrical rim material, the depth of the depression is still small at the initial stage of pressing by the pressing roll. When the rim material line is shallow, the wall of the cylindrical rim material still extends almost linearly, so the axial force of the clamping pressure by the pair of forming rolls is applied as a compressive force to the rim material wire extending almost linearly, and the rim material wire is almost linearly extended. Do not generate bending force. It is only after the depth of the recess has increased that the axial force changes to a bending or buckling force in the recess.

An object of the present invention is to provide a method for forming a rim of an automobile wheel that can further reduce the clamping pressure caused by shaping rolls, that is, the axial load, compared to the rim forming method disclosed in British Patent No. 487820. .

[Means for Solving the Problems] According to the present invention, the above problems are achieved by the following method for forming a rim of an automobile wheel. That is, pressing a portion of the cylindrical rim material in the circumferential direction from the outer circumferential side of the rim material toward the inner circumferential side in the radial direction using a radial pressing roll to form a recess; A rim is formed by partially applying an axial compressive force to the rim material in the circumferential direction by a pair of rotating shaping rolls whose axes are tilted to each other from both axial ends of the rim material. In a method for forming a rim of an automobile wheel, the radial pressing position of the rim material by the radial pressing roll is shifted in the circumferential direction of the rim material from the axial compression position of the rim material by the shaping roll. Characteristic method of forming automobile wheel rims.

[Operation] In the method of the present invention, the radial pressing force of the radial pressing roll against the cylindrical rim material is required to be the same as the radial pressing force in the rim forming method disclosed in British Patent No. 487820. However, the clamping pressure on the rim material by a pair of shaping rolls whose axes are tilted to each other is much smaller than the clamping pressure on the rim material by a pair of shaping rolls in the rim forming method disclosed in British Patent No. 487820. It's over.
This is because the depressions formed by the radial pressing rolls are offset in the circumferential direction from the part pressed by the pair of shaping rolls, so that after the depressions are made to a sufficient depth, , due to the rotation of the rim material that rotates with the rotation of the shaping roll,
The recessed portion is sent to a position where it is clamped by a pair of shaping rolls, and the axial force from the shaping rolls creates a bending force in the recess that is already deep enough, which can cause bending deformation and buckling deformation. It is from.

[Example] Hereinafter, a preferred example of the method for molding a rim of an automobile wheel according to the present invention will be described with reference to the drawings.

2 and 3 show an apparatus according to an embodiment of the invention. In the figure, reference numerals 1 and 2 are a pair of shaping rolls, which are capable of applying pressure in a direction toward each other in the axial direction. The shaping rolls 1 and 2 are tilted symmetrically by an arbitrary angle α from the same straight line A, and can rotate around the tilted axes B and C. The rotational force is provided by another rotational drive device (not shown).

A pair of guide rolls 3, 4 are provided below the center of the pair of shaping rolls 1, 2, and these guide rolls 3, 4 can move forward and backward relative to both ends of the cylindrical rim material. Further, a radial pressing roll 5 is provided above the center of the pair of shaping rolls 1 and 2, and the radial pressing roll 5 is rotatable around its axis. The rim material can be moved in the radial direction from the outer circumferential side to the inner circumferential side to form a depression. As shown in FIG. 3, the center of rotation O of the forming rolls 1 and 2 is located on an extension of the axis X of the radial pressing roll 5 in the pressing direction.

FIG. 3 shows the device viewed from the side, and the pressing position E of the rim material by the radial pressing roll 5 is located between the pair of inclined shaping rolls 1 and 2.
The position is shifted in the circumferential direction of the rim material from the part to which the largest load is applied (the shortest distance part D between the pair of shaping rolls 1 and 2). The angle β indicates the angle corresponding to the shifted circumferential distance.

In this way, the angle β is the deviation between the shortest distance part D of the shaping rolls 1 and 2 and the pressing center E of the radial pressing roller 5, and the difference between the compressed area by the shaping rolls 1 and 2 on the rim material 6 and the radial direction. The areas pressed by the pressure roller 5 are designed to partially overlap. As a result, the formation of the recess 7 is slightly preceded by the formation of the flaring portion 8.

In the apparatus configured as described above, the rim of the automobile wheel according to the present invention is formed as follows.

First, a cylindrical rim material 6 as shown in FIG. 4A is prepared by winding and rounding a flat rim material, and seal-welding the abutting portions by flash butt welding or the like.

Next, the radial pressing roll 5 is pressed locally onto the cylindrical rim material 6 on its circumference to form a depression 7. Furthermore, a pair of left and right shaping rolls 1, 2
The cylindrical material 6 is rotated by pinching a portion of the rim material 6 in the circumferential direction from both ends. When the depression 7 formed by the radial pressing roll 5 is rotated by the rotation of the rim material 6 to the clamping position by the shaping rolls 1 and 2, the axial compressive force by the shaping rolls 1 and 2 is as follows. The recesses 7, which have already been recessed to a sufficient depth, act as bending and buckling forces, making it easy to form the rim into a desired shape and bending the rim material 6 in the axial direction, as shown in FIG. 4B. Apply flaring molding to both ends. During this formation, the guide rolls 3, 4
guide and support the lower part of the rim material 6, which is being formed while approaching each other. Since this forming and flaring processing is applied locally on the circumference of the cylindrical rim material 6, axial bending stress and axial force mainly act, and the processing is performed with a relatively small load. Since the axial force is applied after the recess 7 is formed to a sufficient depth, a smaller axial compressive force is required than in the conventional method in which recess shaping and axial compressive force are applied at the same circumferential position.

More specifically, FIG. 5 corresponds to FIG. 4, and shows the cylindrical rim material 6 in the middle of being processed. As is clear from the figure, the recess 7 is located at a position offset from the flaring portion 8 (the flaring portion 8 is formed at the shortest distance D between the pair of shaping rolls) in the circumferential direction of the rim.

From the state shown in FIG. 5, as the left and right shaping rolls 1 and 2 rotate, the depression 7 moves to the clamping position of the shaping rolls 1 and 2, and as shown in FIG. Molding is performed. In this case, since the recess 7 is shifted in the circumferential direction of the rim material from the position of the clamping pressure by the shaping rolls 1 and 2, as the rim rotates, it gets stuck in the clamping pressure part where axial stress is applied, and the recess 7 Axial bending force and buckling force are applied, and forming is easily performed with small shaping roll clamping pressure. In other words, by molding the recess 7 a little earlier than molding the flaring portion 8, molding can be performed with a smaller pressure than when applying pressure to the rim material wall that extends in a substantially straight line as in the past. . Then, the final molded rim shown in FIG. 4 can be obtained.

[Effects of the Invention] When the method for forming a rim of an automobile wheel of the present invention is used, the pressing position by the radial pressing roll and the clamping position by a pair of forming rolls whose axes are inclined to each other are set to the same position on the rim material. Since they are shifted from each other in the circumferential direction, a sufficiently deep depression is already formed by the radial pressing rolls before the clamping process by the shaping rolls, and in such a shape, the axial compressive force by the shaping rolls is When the recess reaches the clamping pressure position, the bending force and buckling force change greatly depending on the recess, so forming can be performed with a small axial force, and the clamping pressure of the shaping roll can be controlled as disclosed in British Patent No. 487820. This can significantly reduce the shaping roll clamping pressure of the conventional method, making it possible to downsize the device and reduce energy consumption.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a rim showing the conventional method of forming an automobile wheel rim in the order of steps, Fig. 2 is a front view of an apparatus for carrying out the method of the present invention, and Fig. 3 is an embodiment of the present invention. Side view of the device to be used, Figure 4 A, B,
C and D are cross-sectional views showing the cross-section of the rim according to the present invention in the order of steps, and FIG. 5 is a perspective view of the rim material in the step B of FIG. 4. DESCRIPTION OF SYMBOLS 1, 2... Shaping roll, 3, 4... Guide roll, 5... Radial direction press roll, 6... Cylindrical rim material, 7... Recess, 8... Flaring part.

Claims (1)

[Claims] 1 A cylindrical rim material is pressed radially from a radially outer circumferential side of the rim material toward an inner circumferential side using a radial pressing roll to form a recess in the circumferential direction of the rim material; An automobile in which a rim is formed by partially applying an axial compressive force to the rim material in the circumferential direction by a pair of rotating shaping rolls whose axes are tilted to each other from both axial ends of the rim material. In the method for forming a rim of a commercial wheel, the radial pressing position of the rim material by the radial pressing roll is from the axial compression position of the rim material by the shaping roll,
A method for forming a rim for an automobile wheel, characterized in that the rim material is shifted in the circumferential direction.