JPH10180387A - Production of rim blank for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict the generation of cracks at the tip part of flange after forming of rim shaping. SOLUTION: A flat platelike rim blank 4 is passed through a pair of rolls 1, 2, rolled and reduced in thickness in a stage of being in a flat plate, that is, in the stage after rolling and slitting to the stage of uncoiling and cutting in a regulated dimension. Or, by drawing the flat platelike rim blank 4 with a drawing die, the requiring place is reduced in thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rim material for a vehicle wheel.

[0002]

2. Description of the Related Art Two-piece disc wheels for automobiles are:
It is made by welding and joining rims and discs that are separately manufactured. In manufacturing the rim, the rim flat plate material for the wheel is rolled, and the rim flat plate material for the wheel is
The wheel rim flat plate material that has been slit into slits is coiled, the coiled wheel rim flat plate material is supplied to the rim forming process, and the wheel rim flat plate material is uncoiled in the rim forming process. , Cut into fixed size, rounded, butt-welded, flared,
Form into rim shape. Japanese Patent Application Laid-Open No. 55-33843 discloses a method for preventing a decrease in strength due to a decrease in the thickness of a corner portion at a rim forming step, after forming a straight cylindrical rim material, and before forming a rim shape. The cylindrical rim material is sandwiched and pressed between two grooved, approximately the same diameter forming rolls,
It discloses that a so-called rolling step is provided in which each of the corner portions curved in the rim forming step is brought close to each other to partially increase the thickness in the width direction of the rim material. Partial thickening reduces the thickness of portions other than the thickened portion, for example, the flange portion and the rim bead seat portion.

[0003]

However, according to the stress analysis of the rim by the inventor using the finite element method, a portion requiring a large thickness in terms of strength and rigidity is a drop portion or a sidewall in the rim cross-sectional shape. It has been found that they are flanges and rim bead seats rather than corners in the sections. Therefore, Japanese Patent Application Laid-Open No. 55-33
If the corner portion is simply made thicker as disclosed in Japanese Patent No. 843, it is impossible to effectively reduce the thickness and weight of other portions, and if the corner portion such as a drop portion and a side wall portion is increased, unnecessary portions are unnecessary. Was found to cause an increase in weight. Further, in order to roll by a roll in a straight cylindrical stage as disclosed in JP-A-55-33843, one roll 20 must be disposed in a rim material 21 as shown in FIG.
Since the diameter of the roll must be smaller than the diameter of the rim material, the diameter of the bearing that supports the roll is limited, and the rolling load is limited. Further, when a plurality of portions in the axial direction of the cylindrical rim material are simultaneously rolled by a grooved roll at the stage of forming into a straight cylindrical shape as disclosed in Japanese Patent Application Laid-Open No. 55-33843, the material cannot escape in the axial direction, (Therefore, it extends only in the radial direction). Also, in the roll forming for forming the rim shape, the rim material is processed to expand in the radial direction, so that the maximum elongation at the tip of the rim flange exceeds 30%. Therefore, cracks starting from both ends of the rim flange (cracks 23 at the tip of the rim flange 22 shown in FIG. 8)
Is easy to occur. The object of the present invention is not limited by the diameter of the bearing that supports the roll to the rolling load, and can suppress the elongation in the direction corresponding to the radial direction of the rim material at the time of rolling if necessary, after forming the rim shape. An object of the present invention is to provide a method of manufacturing a rim material for a wheel, which is capable of suppressing the occurrence of cracks at the front end of a rim flange.

[0004]

The present invention to achieve the above object is as follows. (1) Rolling the wheel rim plate material, slitting the wheel rim plate material to the width of one rim, coiling the slit rim plate material, and coiling the wheel rim plate material Is supplied to the rim forming process, and the rim flat plate material for the wheel is uncoiled, cut to a fixed size, rounded, and butt-welded at the rim forming process,
In the method for manufacturing a rim material for a wheel which is flared and formed into a rim shape, in a stage after rolling and before a fixed size cutting, a drop portion, a side wall portion, a rim bead seat portion of a rim plate material for a wheel after rim forming. A method for manufacturing a rim material for a wheel, comprising rolling and reducing the thickness of a portion to be formed. (2) Rolling the wheel rim plate material, slitting the wheel rim plate material to the width of one rim, coiling the slit wheel rim plate material, coiling the wheel rim plate material Is supplied to the rim forming process, and the rim flat plate material for the wheel is uncoiled, cut to a fixed size, rounded, and butt-welded at the rim forming process,
In the method for manufacturing a rim material for a wheel which is flared and formed into a rim shape, in a stage after rolling and before a fixed size cutting, a drop portion, a side wall portion, a rim bead seat portion of a rim plate material for a wheel after rim forming. A method for producing a rim material for a wheel, wherein a portion to be formed is reduced in thickness by drawing.

In the method (1) of the present invention, rolling is performed on the rim material while the rim material is in a flat state, so that the roll diameter, bearing diameter, and rolling load used for rolling are determined by the rim diameter. And can be set relatively large freely. In addition, since the rim material is rolled when the rim material is in the flat state, the rim material is rolled in order from the center in the width direction to the end, so that the flat material is released due to the escape of extra thickness at the time of rolling. Can be released in the direction perpendicular to the longitudinal direction (corresponding to the circumferential direction when the annular rim is formed) of the flat plate material (the axial direction when the annular rim is formed),
The influence on the flange portion that extends most in the rim shape forming process can be reduced, and the occurrence of cracks in the flange portion can be suppressed. In the method of the present invention (2),
By drawing the rim material while the rim material is in the flat state, the required cross-sectional shape is formed. The required cross-sectional shape of the rim material can be accurately formed without performing.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a rim material for a wheel according to an embodiment of the present invention includes a first embodiment shown in FIGS.
It includes the second embodiment shown in FIG. 3 and the third embodiment shown in FIG. 5 and 6 are applicable to the first embodiment and the second embodiment. Portions common to all embodiments of the present invention are denoted by the same reference numerals throughout all embodiments of the present invention.

First, portions common to the first and second embodiments of the present invention will be described with reference to FIGS. 1, 2, 5, and 6. FIG. The method part common to the first embodiment and the second embodiment of the present invention is to roll the rim plate material 4 for a wheel, slit the rim plate material 4 for a wheel to a width of one rim,
The slit rim flat plate material 4 for a wheel is coiled, and the coiled rim flat plate material 4 for a wheel is supplied to a rim forming process. Cut to fixed length to the circumference,
The rim flat plate material 4 that has been cut to size is rounded, and both ends in the circumferential direction of the rounded rim material are butt-welded to form a straight cylindrical rim material. Both ends in the axial direction of the straight cylindrical rim material are flared. In a method of manufacturing a rim material for a wheel in which a ring (expanded) and flared annular rim material is formed into a rim shape through a forming process using multi-stage forming rolls, after a slit process after rolling and fixed-size cutting. In the previous continuous rim plate material stage, using a rolling device in which a pair of rolls 1 and 2 are arranged at least one stage in the rim material feed direction (through the rim plate material 4 between the pair of rolls 1 and 2), Drop portion 4e of rim plate material 4 for wheel after rim molding,
A step of rolling and reducing the thickness of the portions to be the sidewall portions 4d and the rim bead seat portions 4b is included. FIG. 1 shows a case where rolling is applied to an uncoiled flat rim material.

In the rolling step, as shown in FIG. 2, the flat rim material 4 is processed by a processing roll 1, a drop portion 4e, a side wall portion 4d, and a bead sheet portion 4b of a product rim.
To the product rim flange 4a and each corner 4f,
g, 4h Roller roll 2 with irregularities to make it thinner
By rotating and driving at least one of the pair of rolls 1 and 2 while sandwiching and pressing the flat rim material 4 between them (when one is driven to rotate, the other hangs around), the widthwise direction is increased. The rim material 4 is formed into an unevenly thick plate-shaped rim material 4 having an uneven thickness. FIG. 4 shows a rim flat plate material 4 for a wheel.
This shows where the reduced pressure portion is located after the reduced thickness portion and the rim shape are formed, and the hatched portion is the portion reduced in pressure by rolling. In FIG. 5, reference numeral 4c denotes a hump portion of the rim.

Since the rim material 4 is rolled while it is in a flat plate shape, neither of the pair of rolls 1 and 2 is inserted into the annular rim material, and the roll diameter must be smaller than the diameter of the annular rim material. There is no. Therefore, the diameters of the rolls 1 and 2 and the diameters of the bearings respectively supporting the rolls 1 and 2 are not limited by the diameter of the annular rim material, and the rolling load is not limited by the diameter of the annular rim material.

In order to obtain a large rolling amount with a relatively small pressing force, the diameter of one of the pair of rolls 1 and 2 is reduced as shown in FIG.
However, when the diameter of the roll 2 is reduced, the roll 2 having a small diameter is elastically deformed and deformed during rolling. Therefore, the roll 2 having a small diameter is prevented by a backup roll 3 from the opposite side to the other roll 1 in order to prevent the deformation. It is desirable to hold down.

The rolling pressure P is reduced by reducing the diameter of the roll 2.
The reason why is reduced will be described. FIG. 9 shows a conventional two rolls 1 having substantially the same diameter (JP-A-55-33843).
2 shows that a right-cylindrical raw material 4 ′ is being roll-formed using 2 ′ and 2 ′. In this case, the pressing force P when machining the groove in the cylindrical material by rolling is obtained by the following equation. P = k · B · L · K (1) However, k = rolling resistance B = rolling pressure width (axial direction) L = material and roll contact width (circumferential ^{direction) K = {e m · L} / (h-1 )｝ / {M · L / h} In order to reduce P, k, B,
L and K may be reduced, but k cannot be changed in order to secure the strength of the rim, and B cannot be reduced from the original purpose of reducing the weight of the rim.

In order to reduce L, the amount of compaction should be reduced,
Either the contact width between the material and the roll must be reduced or the roll diameter must be reduced. Among them, the former (reducing the amount of compaction) means reducing the amount of pressurization, and mass-produced products such as wheel rims pose a problem in terms of productivity. In the latter case (reducing the contact width between the material and the roll), there is no bearing for receiving the roll, so that the rolling equipment cannot be realized. The above explanation is
Although this is the case of a straight cylindrical rim material, the present invention can also be applied to a flat rim material.

However, in the method of the present invention, the roll 2 is made small in diameter, and L in the equation (1) is reduced to make the rolling pressure P smaller than that of the conventional method (however, the formability is not changed). The problem from the bearing is solved by reducing the bearing load of the roll. Roll 2 and backup roll 3
, The rolling pressure P is divided into P ₁ and P ₂ , and the bearing becomes easier. The roll 2 having a small diameter has no problem because the roll 2 is backed up by the backup roll 3 having a large rigidity, and the roll 2 does not escape from the material 4 and does not hinder thin-wall forming. According to the method of the embodiment of the present invention, an arbitrary portion of the rim material 4 can be freely thinned, and cannot be achieved by the conventional method.
% Of the rim can be reduced in weight.

A side guide (guide roll) as a restraining means for restraining the flat rim material 4 from both sides in the width direction in order to accurately reduce the thickness of the target position without causing lateral displacement.
17 are provided, and the rim material 4 is
Sandwich it in between. This makes it difficult for the rim material 4 to be laterally displaced during molding, and facilitates dimensional control. This means that it is easy to accurately reduce the thickness of the portion to be reduced without displacement.

Next, parts unique to the first and second embodiments of the present invention will be described. In the first embodiment of the present invention, as shown in FIGS. 1, 2 and 4, a pair of rolls 1 and 2 (roll 1 is also referred to as a processing roll, and roll 2 is also referred to as a rolling roll)
Are arranged in a plurality of stages in the feed direction of the flat rim material 4 (3 in the illustrated example).
Step) is installed. The side guide 17 is provided at a position immediately after the rolls 1 and 2 of each stage.

As shown in FIG. 2, a plurality of rolls 1, 2
Of the rolls 1 and 2 provided on the upstream side in the rim material feeding direction, the central part in the width direction of the flat rim material 4 is rolled and reduced in thickness, and the stage provided on the downstream side in the rim material feeding direction is reduced. Rolls 1 and 2 roll and reduce the center of the flat rim material 4 in the width direction. In the example of FIG. 2, the portion corresponding to the rim drop portion 4e is rolled in the first process, the portion corresponding to the rim sidewall portion 4d is rolled in the second process, and the rim bead seat portion 4b (hump portion) is rolled in the third process. If there is 4c, the hump portion 4c is also pressed.

[0017] This makes it possible to release the excess thickness at the time of compaction in the direction perpendicular to the longitudinal direction of the flat rim material 4, that is, in the width direction of the flat rim material 4. Elongation and plastic strain in the longitudinal direction can be reduced. As a result, when the rim is formed and formed into an annular rim material after rolling, the circumferential distortion of the flange end (the circumferential direction corresponds to the longitudinal direction of the flat plate material stage) is reduced,
The occurrence of cracks at the end of the flange can be prevented. In addition, by using a plurality of stages, the rolling load per stage can be reduced. Also, the example of FIG. 1 shows the rolls 1 and 2 of each stage having substantially the same diameter.
One roll 2 may have a smaller diameter than the other roll 1.

In the second embodiment of the present invention, as shown in FIG. 3, a pair of rolls 1 and 2 (the roll 1 is also referred to as a processing roll and the roll 2 is also referred to as a rolling roller) are fed in the feeding direction of the flat rim material 4. 1 (only one of the three stages in FIG. 1)), and the pair of rolls 1 and 2 of the single stage simultaneously reduce the entire thickness reduction portion (corresponding to the rim drop portion 4e) in the material width direction. (The portion corresponding to the rim sidewall portion 4d and the portion corresponding to the rim bead seat portion 4b). The side guide 17 is provided at a position immediately after the single-stage rolls 1 and 2. Since the escape of the excess thickness at the time of compaction at the central portion is restricted by the compaction at the end portion, the escape property of the extra thickness of the compaction portion at the central portion in the width direction in the width direction of the flat rim material is the first embodiment. However, the size of the rolling device in the flat rim material feeding direction is smaller than that of the first embodiment.

Next, a third embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In the third embodiment, the wheel rim plate material 4 is rolled, and the wheel rim plate material 4 is rolled.
Is slit into a width of one rim, the slitted wheel rim plate material 4 is coiled, and the coiled wheel rim plate material 4 is supplied to a rim forming process.
In the rim forming step, the rim flat plate material 4 for a wheel is uncoiled, cut into fixed lengths for one rim, and the cut rim flat plate material 4 is rounded, and both ends in the circumferential direction of the rounded rim plate material Butt-welded parts to form a straight cylindrical rim material, flaring (expanding) both ends in the axial direction of the straight cylindrical rim material, and forming the flared annular rim material into a multi-stage forming roll In the method of manufacturing a rim material for a wheel, which is formed into a rim shape through a rim, in a continuous rim plate material stage after slit processing after rolling and before fixed-size cutting, as shown in FIG. ,
After the formation of the rim shape, the reduced thickness portion of the wheel rim flat plate material 4 is continuously reduced in thickness, assuming a portion that can be reduced in thickness. In the thickness reduction of the wheel rim material by the drawing process, since the material does not extend in the width direction and the longitudinal direction as compared with the rolling, the thickness reduction can be performed with high accuracy.

[0020]

According to the method of the first aspect of the present invention, since the rim material is rolled and reduced while the rim material is in a flat plate shape, the roll diameter, the bearing diameter, and the rolling load are reduced from the diameter of the annular rim material. Can be selected relatively freely without being restricted by the above. Further, in the method of claim 1 of the present invention, since the rim material is subjected to rolling in a stage where the rim material is in a flat state, the rim material can be rolled in order from the center in the width direction to the end of the flat material.
By doing so, the elongation of the flat plate material due to the escape of the excess material during rolling can be released in the direction perpendicular to the longitudinal direction of the flat plate material, and the influence on the flange portion that extends most in the rim shape forming process is reduced. And the occurrence of cracks in the flange portion can be suppressed. According to the method of claim 2 of the present invention, the required cross-sectional shape is formed by subjecting the rim material to drawing at the stage where the rim material is in a flat state. The required cross-sectional shape of the rim material can be accurately formed without worrying about the elongation of the material in the direction and the longitudinal direction.

[Brief description of the drawings]

FIG. 1 is a perspective view of an apparatus for performing rolling in a method of manufacturing a rim material for a wheel according to a first embodiment of the present invention.

FIG. 2 is a front view showing a plurality of steps of rolling in a method of manufacturing a rim material for a wheel according to the first embodiment of the present invention.

FIG. 3 is a front view illustrating a rolling step of a method for manufacturing a rim material for a wheel according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating forming of a wheel rim material by drawing according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view showing the correspondence between the flat rim material and the reduced thickness portion of the rim after forming the rim.

FIG. 6 is a side view showing a case where the diameter of a compaction roll is reduced by using a backup roll.

FIG. 7 is a perspective view of an apparatus of a conventional local thickening method.

FIG. 8 is a perspective view showing a crack at an end of a rim flange in a conventional straight cylindrical rolling method.

FIG. 9 is a side view of a conventional rolling method of the same-diameter roll.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing roll 2 Rolling roll 3 Backup roll 4 Rim material 5 Die for drawing 17 Side guide

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B21H 8/02 B21H 8/02

Claims (2)

[Claims] 1. A wheel rim plate material is rolled, a wheel rim plate material is slit into a width of one rim, and the slit wheel rim plate material is coiled, and a coiled wheel rim is formed. The rim for the wheel which supplies the flat plate material to the rim forming process, uncoils the rim flat wheel material for the wheel in the rim forming process, cuts to a fixed size, rounds, butt-welds, flares and forms the rim shape In the method of producing the material, at the stage after the rolling and before the fixed size cutting, the portion of the rim flat plate material for the wheel, which becomes the drop portion, the sidewall portion, and the rim bead seat portion after the rim forming, is rolled and reduced in thickness. A method for producing a rim material for wheels. 2. The wheel rim plate material is rolled, the wheel rim plate material is slit into a width corresponding to one rim, and the slit wheel rim plate material is coiled. The coiled wheel rim The rim for the wheel which supplies the flat plate material to the rim forming process, uncoils the rim flat wheel material for the wheel in the rim forming process, cuts to a fixed size, rounds, butt-welds, flares and forms the rim shape In the material manufacturing method, at the stage after rolling and before cutting to a fixed size, a portion of the rim flat plate material for a wheel, which becomes a drop portion, a sidewall portion, and a rim bead seat portion after rim forming, is reduced in thickness by drawing. A method for producing a rim material for a wheel, comprising: