JPH0976039A - Rolling method for annular rim stock for wheel and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rolling method and device capable of reducing thickness reducing force when an annular rim stock is subjected to thickness reducing with rolling. SOLUTION: A first forming roll 1 is arranged inside an annular rim stock 4 and a second forming roll 2 having a smaller diameter than the first roll is arranged outside the stock, while a back up roll 3 backs up the second forming roll 2, the annular rim stock 4 is subjected to thickness reducing. The device consists of the first roll 1 arranged inside the annular rim stock 4, the second roll 2 having a smaller diameter arranged outside the annular rim stock 4 and the back up roll 3 to back up the second roll 2 in contact with the rim stock from the opposite side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an annular rim material for an automobile wheel by rolling and a device used directly for carrying out the method.

[0002]

2. Description of the Prior Art Two-piece disc wheels for automobiles are
It is manufactured by combining separately manufactured rims and disks and welding them together. In the production of a rim, a flat plate is rolled and the ends are butt-welded to form an annular rim material, which is passed through a multi-stage roll to be formed into a rim shape. JP-A-55-33
No. 843 gazette discloses an annular rim material with a groove, after the annular rim material is manufactured and before the rim shape forming, for the purpose of preventing the bending portion from being thinned and the strength being lowered in the rim molding stage. It is sandwiched and pressed by a first forming roll and a second forming roll having almost the same diameter, and so-called compaction is performed to bring the part into a curved portion in the rim forming stage and to partially increase the width of the rim material. It is disclosed to provide a rolling step to thicken.
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 using the finite element method, a portion requiring a large thickness in terms of strength and rigidity is a drop portion or a sidewall portion in the rim cross-sectional shape. It has been found to be the flange and rim bead seat sections rather than some curved sections. Then, even if the conventional roll groove is used to reduce the thickness of the drop portion and the sidewall portion by bringing the flange portion and the rim bead sheet portion closer together, the rolling force becomes extremely large (for example, 50 TON or more), and the roll is rolled. A desired rolling compaction cannot be performed due to bending, and the life of the bearing portion that supports the roll cannot be guaranteed. Further, when simply rolling with a grooved roll as in Japanese Patent Laid-Open No. 5533843, the material is laterally displaced as a result of the experiment,
Grooving at the same location was impossible. The cause is that the material size is not always constant on the left and right, the plate thickness naturally varies, and the required groove machining amount is not the same on the left and right, so the material stretches unevenly on the left and right, causing lateral displacement and Processing is impossible. In addition, I tried to give a guide by a roll guide or a fixed plate to each end of the work as a side guide to prevent lateral displacement, but as the processing progresses, the material expands in the width direction and interference with the guide occurs, There was a problem that machining could not be continued and the material edge was worn. An object of the present invention is to provide a rolling method and apparatus for an annular rim material for a wheel, which can partially reduce the thickness of the annular rim material in the width direction with a smaller rolling force than the conventional one. Another object of the present invention is to provide a rolling method and device for an annular rim material for a wheel, which can prevent lateral displacement of the annular rim material during rolling.

[0004]

The present invention to achieve the above object is as follows. (1) A method of arranging a first forming roll on the inner side of an annular rim material and a second forming roll on the outer side thereof to partially thin the annular rim material in the material width direction by rolling. For a wheel that uses a roll having a smaller diameter than the first forming roll as the second forming roll, and backs up the second forming roll from a side opposite to the first forming roll with a backup roll to perform rolling compaction. Rolling method for annular rim material. (2) A device for partially thinning an annular rim material in the material width direction by rolling, wherein the first forming roll disposed inside the annular rim material and the outside of the annular rim material. A second roll having a diameter smaller than that of the first forming roll.
And a backup roll that backs up the second forming roll from the side opposite to the first forming roll. (3) The rolling device for an annular rim material for a wheel according to (2), wherein the first forming roll is provided with restraining means for restraining the annular rim material from both sides in the axial direction.

In the method (1) and the apparatus (2), since the small diameter roll is used for one of the first and second forming rolls (second forming roll), the rolling pressure becomes small. .
As a result, the life of the roll bearing is not an issue.
The bending of the small diameter roll due to the small diameter roll can be suppressed by the backup roll. Since the diameter of the backup roll does not affect the rolling force, it can be freely increased. This allows the desired reduction of the thickness of the annular rim blank by rolling. In the device of the above (3), since the restraint means is provided, it is possible to prevent lateral displacement during rolling of the annular rim material.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a rolling device for an annular rim material for a wheel according to an embodiment of the present invention will be described with reference to FIGS. The rolling device for the annular rim material for wheels according to the embodiment of the present invention is a device for partially thinning the annular rim material 4 in the material width direction by rolling, and is a device arranged inside the annular rim material 4. 1 forming roll 1 and annular rim material 4
A second smaller diameter than the first forming roll 1 arranged outside the
Forming roll 2 and a backup roll 3 for backing up the second forming roll from the side opposite to the first forming roll 1. At least one of the first forming roll 1 and the second forming roll 2 has unevenness for partially reducing the thickness of the material 4 in the width direction during material rolling.

The first roll 1 has an inner diameter D of an annular rim material 4.
Fully utilizing the outer diameter d ₁ (however, d ₁ <
It is a roll of D). The minimum wheel rim diameter is 10 inches, and the minimum material inner diameter is about 250 mm. Since the rolling force P becomes smaller as the diameter of the second roll 2 becomes smaller as described later, the diameter d ₂ of the _second roll ₂ is made much smaller than the diameter d ₁ of the first roll 1. . But,
If it is made too small, slippage will occur due to the balance between the friction coefficient between the roll 2 and the material 4, making it impossible to process.
The minimum value of the diameter d ₂ of the forming roll 2 is preferably about 90 m.
m (90 ± 10 mm, but it is possible to make it smaller than this, but the limit of the amount of rolling pressure per revolution becomes large), and both the first and second forming rolls 1 and 2 are driven. To do so. The backup roll 3 contacts the second forming roll 2. The backup roll 3 has a diameter larger than that of the second forming roll 2 and has substantially the same diameter as that of the first forming roll 1.

The first forming roll 1 is fitted with a bearing 5 to the upper roll.
Support is rotatably supported by the support member 10 and supports the upper roll.
The holding member 10 is fixed to the upper ram 11 of the press, and
It is vertically moved together with the upper ram 11 by the binder 15. Rolling pressure
Is the force exerted by the hydraulic cylinder 15. First forming roll
1 is for the motor 8 attached to the upper roll supporting member 10.
Is driven more. The rolling force P of the first forming roll 1 is
Reaction force P of forming roll 2₁And backup roll 3
Reaction force P₂(P = P ₁+
P₂). The second forming roll 2 is a lower roll via a bearing 6.
It is supported by the support member 12. Backup roll 3 also
It is supported by the lower roll support member 12 via the bearing 7. under
The roll support member 12 is fixed to the bolster 13 of the press.
It is. The second roll 2 is driven by the motor 9. ring
The first roll 1 is inserted into the strip-shaped rim blank 4 by the first roll.
Remove one bearing 5 of the roller 1 from the first roll 1
Or split the first roll 1 between the bearings 5
Enable it and separate it from each other and insert the rim material from there.
Although it is done by inserting it, such a mechanism does not have a conventional rim component.
Known mechanisms can be used in the form roll.

As a method of accurately reducing the target position without causing lateral displacement, a flange as a restraint means for restraining the annular rim blank 4 shown in FIGS. 4 and 5 from both sides in the axial direction on the first forming roll. 17 is provided and the material is sandwiched between both flanges 17. Therefore, the second roll 2 has a shape in which the diameter is changed by the width that is accommodated in the space between the flanges 17 of the first roll 1. In this case, the height of the flange 17 is such that the lapping margin θ with the material is at least 1 / the entire circumference of the material, as shown in FIG.
It is desirable to be 3 or more. By rolling with the structure of FIG. 4 and FIG. 5, the reduced thickness is limited only to the radial increase, the width does not change, and the dimension management is easy. This means that the final rim size is easily obtained. Further, it can be used together with a fixed side guide (for example, the roll guide 18 in FIG. 4), and the processing can be further stabilized.

Next, a method for rolling the annular rim material for a wheel according to an embodiment of the present invention will be described with reference to FIGS. The method for rolling an annular rim material for a wheel according to an embodiment of the present invention includes a first forming roll 1 inside an annular rim material 4,
A method of arranging a second forming roll 2 on the outside and partially thinning the annular rim material 4 in the width direction of the material by rolling, wherein the second forming roll 2 has a thickness smaller than that of the first forming roll 1. This is a method in which a roll having a small diameter is used, the second forming roll 2 is backed up from a side opposite to the first forming roll 1 by a backup roll 3, and rolling is performed.

The basis of molding is to leave the original plate thickness, strength,
The portion that may be reduced in thickness for rigidity (hatched portion in FIG. 3) is thinned by rolling. Then, the cylindrical rim material is processed into a rim shape by passing through a rim-shaped multi-stage roll as in the conventional case. In FIG. 3, the material 4 is on both sides (inside and outside)
However, it is also possible to make only one side uneven (in that case, only one of the first and second rolls is uneven). FIG. 6 shows a plate thickness distribution of the rim 4 ′ manufactured by the conventional method of Japanese Patent Laid-Open No. 55-33843 for comparison with FIG. However, in FIG. 6, the shaded portion indicates the reduced thickness portion. As can be seen from the comparison between FIGS. 3 and 6, in the method of the present invention, the rim drop portion 4 _e , the sidewall portion 4 _d , the hump portion 4 _{c, and the} like have a large portion (the original thickness) that may be reduced in strength and rigidity. Is 0.5 to 0.9)
In addition to the effective weight reduction of the wheel (about 30%), it is impossible to reduce the weight effectively by the conventional method, and the strength and rigidity of the flange etc. The thickness of the curved portion of the required portion is reduced, which causes problems in strength and rigidity.

The reduction of the rolling force P by reducing the diameter of the second forming roll 2 in the present invention will be described.
FIG. 7 shows that the material 4'is compacted by using two conventional rolls 1 ', 2'having substantially the same diameter. 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 rolling pressure is reduced
Either the contact width between the material and the roll must be reduced or the roll diameter must be reduced. Of these, the former (reducing the amount of rolling) means reducing the amount of pressurization, which is a problem in terms of productivity for mass-produced products such as wheel rims. In the latter case (where the contact width between the material and the roll is reduced), the bearing portion that receives the pressure roll does not have any effect and cannot be established as the rolling equipment. In addition, it is difficult to simply increase the upper and lower rolls and apply a strong pressing force due to the restriction of the inner diameter of the material cylinder.

However, in the method of the present invention, the diameter of the second forming roll 2 is made small, and L in the equation (1) is made small so that the rolling pressure P
Is smaller than the conventional method (however, the formability does not change), thereby reducing the bearing load of all rolls and solving the problem from the bearing. For the second roll 2 and the backup roll 3, the rolling force P is divided into P ₁ and P ₂ , and the bearing becomes easier. Also, the second with a small diameter
Regarding the bending of the roll 2, the second roll 2 is backed up by the backup roll 3 having a large rigidity, so that no problem occurs, and the second roll 2 escapes from the material 4 and hinders thin-wall molding. Absent. According to the method of the present invention, an arbitrary portion of the annular rim material 4 can be freely thinned, and the rim can be reduced in weight by 30%, which cannot be achieved by the conventional method. Further, by pressing the annular rim blank 4 from both sides in the axial direction by the restraining means 17 during rolling, it is possible to accurately reduce the thickness of the rim blank without causing lateral displacement.

[0015]

According to both the method of claim 1 and the apparatus of claim 2, since a roll having a smaller diameter than the first forming roll is used as the second forming roll, the conventional forming using the same diameter roll is performed. Compared with, the rolling force in the annular rim material thickness reduction molding becomes smaller. As a result, the load applied to the roll bearing becomes small, and the problem does not occur in the life of the bearing. Also, since the second forming roll having a small diameter is backed up by the backup roll, it is possible to prevent the second forming roll from flexing in the direction of escaping from the material during rolling, and any portion of the annular rim material can be rotated to any shaft. Can reduce thickness over directional distance. In this thickness reduction, the rim weight is reduced by about 3% compared to the conventional one by reducing the extra thickness of the portion of the annular rim material that will become the drop portion, sidewall portion, and hump portion after the rim shape is formed.
It can be reduced by 0%, contributing to weight reduction of vehicles and improvement of fuel efficiency. Further, according to the apparatus of claim 3, lateral displacement can be prevented by pressing the annular rim material from both sides in the axial direction by the restraining means during rolling, and the thickness can be accurately reduced.

[Brief description of drawings]

FIG. 1 is a front view of a roll portion of an apparatus for carrying out a method for rolling an annular rim material for a wheel according to an embodiment of the present invention.

FIG. 2 is an overall side view of the apparatus of FIG.

FIG. 3 is a flat plate rim material and a portion of which the thickness may be reduced,
It is sectional drawing which shows the relationship with the shape after shape | molding in a rim shape.

FIG. 4 is a partial side view of the apparatus when the restraining means is provided on the first forming roll.

FIG. 5 is a front view of the apparatus of FIG. 4;

FIG. 6 is a cross-sectional view of a rim reduced in thickness by the method of Japanese Patent Laid-Open No. 5-33843.

FIG. 7 is a front view in the case of roll-forming an annular rim material with a conventional roll having the same diameter.

[Explanation of symbols]

 1 1st forming roll 2 2nd forming roll 3 Backup roll 4 Annular rim material 5, 6, 7 Bearing 8, 9 Motor 17 Restraint means

Claims (3)

[Claims] 1. A method for arranging a first forming roll inside a ring-shaped rim material and a second forming roll outside thereof to partially thin the ring-shaped rim material in the material width direction by rolling. Then, a roll having a diameter smaller than that of the first forming roll is used as the second forming roll, and the second forming roll is backed up from the side opposite to the first forming roll by a backup roll to perform the compaction. Rolling method for annular rim material for wheels. 2. An apparatus for partially thinning an annular rim material in the material width direction by rolling, comprising: the first forming roll disposed inside the annular rim material; A ring for a wheel including a second forming roll having a diameter smaller than that of the first forming roll and arranged outside, and a backup roll for backing up the second forming roll from a side opposite to the first forming roll. Rolling equipment for rim material. 3. The rolling device for an annular rim material for a wheel according to claim 2, wherein the first forming roll is provided with restraining means for restraining the annular rim material from both sides in the axial direction.