JPH0891005A - Manufacture of rim for automotive wheel - Google Patents

Abstract

PURPOSE: To provide a manufacturing method for a wheel rim in which the durability for the repetitive load is secured and the weight can be reduced. CONSTITUTION: When a rim 10 is manufactured by rounding a plate-shaped material, the material having the parts for forming the R parts after the rim shaping 15, 16, 18, 21, 22, 24, and 25 which are made thick and other parts made thin in the material stage is used. Even if the load applied to the rim is concentrated at the R parts 15, 16, 18, 21, 22, 24, and 25, the sufficient endurance is secured, and other parts are made thin, and the weight can be reduced.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for manufacturing a rim for an automobile wheel.

[0002]

2. Description of the Related Art Conventionally, automobile wheels are roughly classified into molded products and cast products. Of these, the rim of the molded wheel is manufactured as follows. First, a strip plate having a uniform plate thickness is cut into a rectangular plate material. Then, the plate material is rolled. Then, both ends of the rolled plate in the rolling direction are welded to form a cylindrical shell. Then, the diameters of both ends in the axial direction of the cylindrical raw tube are expanded. Then, a tubular tube whose both ends are expanded is formed into a rim shape by a forming roll.

[0003]

However, since the shape of the wheel rim is complicatedly bent, local stress concentration occurs. Nonetheless, conventional wheel rims must be molded from a material with a uniform thickness to form a rim with a substantially uniform thickness, and in that case it is necessary to match the thickness to the most severe part in terms of strength. However, there was a problem that there was too much room and the weight was increased unnecessarily. An object of the present invention is to provide a method for manufacturing a rim for an automobile wheel, which can prevent excessive strength and increase in weight due to it.

[0004]

According to the present invention, the above object is achieved by the following method of the present invention. Prepare a plate-shaped material, round the plate-shaped material into a cylindrical shape, but abut both ends in the circumferential direction, and weld and join the abutted both ends to form a cylindrical raw pipe, the axial direction of the cylindrical raw pipe In the method for manufacturing a rim for an automobile wheel, which comprises a step of expanding both ends to form a tubular tube with both ends expanded and forming the tube with both ends expanded into a rim shape with a forming roll, A method of manufacturing a rim for an automobile wheel, wherein, in a step, a portion having an R shape in the axial direction after being formed into a rim shape is connected to the portion to have a larger thickness than a portion extending substantially linearly in the axial direction.

[0005]

When the axial bending stress generated in the rim when the tire ground pressure is applied to the rim through the tire is measured, the stress generated in the axially R-shaped portion of the rim is measured in the axial direction connected to the rim. It was found that the stress was larger than the stress generated in the substantially linearly extending portion. In the present invention, since the thickness generated in the R portion is made larger than that of the straight line portion that follows, the stress generated in the R portion can be relaxed, and the repeated load can be sufficiently endured. The amount of flutter can be reduced and the weight can be reduced. In the current metal plate manufacturing technology, a metal plate having a thickness changed in the width direction can be manufactured by rolling with a roll having a diameter changed according to the position of the roll in the longitudinal direction.

[0006]

1 to 3 show an embodiment of the present invention,
FIG. 4 shows stress data of a conventional wheel. As shown in FIG. 3, the method of manufacturing a rim for an automobile wheel according to the present invention includes (a) a step of preparing a plate-shaped material 1 made of steel or an aluminum alloy, and (b) the plate-shaped material 1 in the longitudinal direction thereof. (L
Direction) in the form of a cylinder with a coiler 2 (the rounded one is indicated by 3), and (c) a step of butt-welding both ends of the rolled one in the circumferential direction to form a cylindrical raw tube 4 ( (The welded portion is indicated by 5), (d) a step of expanding both axial end portions of the cylindrical raw pipe 4 to form the expanded tubular pipes 6 at both ends, and (e) forming with the first forming roll 7. , (F) forming with the second forming roll 8 and (g) forming sequentially with the third forming roll 9 to form a rim 10 having a rim shape of the final shape.

Here, in the step (a) of preparing the plate-shaped raw material 1, as shown in FIG. 2, the plate-shaped raw material 1 has its thickness changed at each portion in the width direction and is formed into a rim shape. The portion having an R (curved) shape in the axial direction when pressed is thicker than the portion that extends in a substantially straight line following the portion. As shown in FIG. 1, for example, the flange portions 11 and 1 may be used as the portion that forms the R shape in the axial direction when formed into the rim shape.
2, the connection portions 15 and 16 between the bead seat portions 13 and 14,
And a connecting portion 1 between the bead seat portion 14 and the hump portion 17.
8 and the connection portions 21 and 22 between the bead seat portion 13 or the hump portion 17 and the drop portion side walls 19 and 20, and the connection portions 24 and 25 between the drop portion side walls 19 and 20 and the drop portion bottom wall 23. The linear portions include the rim bead seat portions 13 and 14, the hump portion 17, the drop portion side walls 19 and 20, and the drop portion bottom wall 23. In order to correspond to FIG. 1, the plate-shaped material 1 in FIG. 2 is also provided with the reference numeral after the rim is formed. The thickness changes smoothly in a stepped manner to suppress stress concentration. Further, the change in thickness is provided by making only one surface of the plate-shaped material 1 uneven so as to facilitate rolling. Then, the uneven surface should be brought inside when rolling. This is for ensuring the airtightness by allowing full contact with the bead portion of the tire when the bead portion of the tire is seated after the rim shape is formed.

The reason why the thickness of the R portion is increased will be described with reference to FIG. FIG. 4 shows that when a load corresponding to a tire ground pressure load is applied in the radial direction of the rim to the bead seat portion of the flange portion of the conventional rim manufactured from a plate-shaped material having a uniform thickness,
The result of measuring the axial bending stress generated in the rim by attaching a strain gauge to the rim is shown. Here, what does not consider the tire pressure load applied from the tire to the rim is that the load that causes the rim to crack and damage is the ground pressure load repeatedly applied for each rotation of the wheel, and not the tire pressure load applied steadily. Because. As is clear from FIG.
A bending stress larger than that of the straight portion connected to each R portion of the rim is generated, and each R portion has a maximum value. Each R
By making the thickness of the part to withstand the above maximum value and making the thickness of the straight part that follows it smaller, the strength margin generated in the straight part is reduced compared to the conventional rim, and the weight Has been reduced.

The dimensions of an example rim in which the thickness of each part is determined so as to satisfy the above conditions are as follows.

Next, the operation will be described. As described above, the rim manufactured from the plate-shaped material 1 is in a state in which, after the rim has been formed, the R portions thereof are thicker than the linear portions that follow respectively, so that the tire ground pressure load is applied to the rim. Even if it is repeatedly applied while the vehicle is running, the stress level is reduced and the fatigue strength is improved. Further, since the straight line portion is thinner than the conventional one, the weight can be reduced and the fuel consumption of the vehicle can be improved. Even if the thickness of the straight line portion is reduced, the stress level is originally small, so there is no problem in terms of durability.

[0011]

According to the present invention, at the stage of plate material, the rim is formed by using a material in which the thickness of the R-shaped portion after forming the rim is large and the thickness of the subsequent linear portion is small. Since the rim is manufactured, it is possible to provide a rim in which after the rim is manufactured, the R portion is kept to have a necessary strength and the other parts are thinner and lighter than the conventional rim.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a rim manufactured by a method for manufacturing an automobile wheel rim according to an embodiment of the present invention.

2 is an end view of the plate-shaped material used in the rim manufacturing of FIG. 1 (end view as seen from the direction A in FIG. 3).

3A and 3B are a cross-sectional view and a perspective view of a rim showing, in the order of steps, a method for manufacturing an automobile wheel rim according to an embodiment of the present invention.

FIG. 4 is an axial bending stress diagram when a tire contact pressure load is applied to a uniformly thick rim.

[Explanation of symbols]

 1 Plate material 10 Rim 15, 16, 18, 21, 22, 24, 25 R part

Claims (1)

[Claims] 1. A plate-shaped material is prepared, the plate-shaped material is rolled into a cylindrical shape, and both ends in the circumferential direction are abutted, and the abutted both ends are weld-joined to form a cylindrical raw pipe, the cylindrical shape The both ends in the axial direction of the raw pipe are expanded to form a tubular pipe with both ends expanded, and the tubular pipe with both ends expanded is formed into a rim shape with a forming roll.
A method of manufacturing a rim for an automobile wheel, which comprises the steps of: preparing a plate-shaped material; connecting a portion having an R shape in the axial direction after being formed into a rim shape to the portion and extending substantially linearly with the axial direction. A method for manufacturing a rim for an automobile wheel, which is characterized in that the thickness is made larger than that of the portion.