JPH05277602A - Method for straightening flatness of work having flat plane like part - Google Patents

Abstract

PURPOSE:To more precisely make the flatness of the flat plane like part of the work, with the small pressing force by applying the expanding force to the work from the inner circumferential hole of the work in the state that the flat plane like part of the work is clamped by pressing to the orthogonal direction against the plane surface. CONSTITUTION:In the state that a disk flat plane like part 124 is clamped by pressing to the orthogonal direction against plane surface, an upper die 30 is lowered more by very little amount, a wheel 110 is expanded and a rim part 110 and a disk part 120 are deformed until the plastic region radiately to the direction of external circumference. In this time, an external circumferential surface 64 of a claw part 52 of a shoe 36 expanded the flat plane like part 124 of the disk part also from the internal circumference side by engaging to the internal circumferential surface of a hub hole 112. In the same time, the shoe 36 works by expanding a curved part 126 of the disk part 124 and a cylinder like part 128 also. Due to the plastic deformation, the wheel 100 is pressed to the internal circumferential surface 20 and shaped to the final shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a straightening method and apparatus for straightening the flatness of a flat part of a work having a flat part, for example, an automobile wheel.

[0002]

2. Description of the Related Art A disk wheel for a vehicle is a rim formed by rolling a flat plate into a cylindrical shape and forming it into a rim shape, or by rolling and shaping a shaped steel having a predetermined sectional shape.
It is manufactured by welding and joining a disc formed by shaping a flat plate into a disc shape.

In order to suppress the vibration while the vehicle is running and stabilize the braking force, the shape of the wheel is required to have a predetermined accuracy. In order to achieve this accuracy, in the conventional stage where the rim and the disc were individually manufactured, the rim of the tire bead contact surface and the gutter surface of the rim, the flutter of the flange portion, and the hub mounting surface of the disc were mounted. It is manufactured by setting the standard value for each swell.

However, even if the accuracy comes out at the stage of a single item,
In the subsequent process of press-fitting the disc into the rim, and subsequently welding the rim and the disc, due to tilting of the rim and the disc due to press-fitting, eccentricity, and deformation due to the heat effect during welding, In some cases, the standard value of the wheel may be exceeded at some stages.

In order to obtain the accuracy of the finished wheel stage,
In some cases, the shape of the wheel is corrected after welding the rim and the disc. Such correction includes flatness correction of the hub portion of the disk. To correct the flatness of this disk part,
Conventionally, there have been the following four methods. (1) A high pressure is applied to the disc hub portion at a right angle to the plane of the hub portion to correct the high pressure. (2) The disc hub is hammered at a right angle to the plane of the hub and straightened with high pressure. (3) As disclosed in Japanese Examined Patent Publication No. 2-36431, the disk hub portion is subjected to leveling correction processing by rollers. (4) Apply cutting machining to the disk hub portion to obtain flatness.

[0006]

However, each of the conventional correction methods has the following problems. In the method of (1), it takes about 120 to correct the disc.
A large press machine of about 0 tons is required, the equipment becomes large scale, and even if a pressing force of 1200 tons is applied,
A swell of about 0.5 mm remains. The method (2) requires a high-pressure press that changes the plate thickness by a browning impact press.
A 00-ton class press is required, and the equipment becomes large-scale.

In the method (3), when the roller is machined, the dimensions and pitch of the hub holes and bolt holes formed in the hub surface are deformed and rounded. Therefore, highly skilled work is required, and the yield is likely to decrease. In the method (4), machining requires a great deal of processing time and cost as compared with molding by pressing or the like, and is not suitable for mass production. Even if the flatness is intended to be reduced by flattening the plate thickness, it is difficult to obtain the flatness because the balance changes due to the residual stress and the flatness comes back up again.

It is an object of the present invention that the flatness of a work having a flat plate portion, for example, an automobile wheel, is flattened by a presser much smaller than the conventional one and can be formed (without cutting). It is an object of the present invention to provide a flattening method for flattening a work having a flat plate-like portion and a device therefor that can be taken out.

[0009]

According to the present invention, the above object can be achieved by a flatness correcting method and apparatus for a work having the following flat plate-shaped portions.

(1) A disk portion having a flat plate-shaped portion having a hub hole in the center and a curved portion on the outer periphery which is curved to the flat plate-shaped portion and a cylindrical portion which is curved to the curved portion; and an annular rim portion. A disc having a smaller diameter than that of the final product, which is welded to the cylindrical portion of the disc portion, is formed, and the wheel is set on the lower mold having a flat upper surface with the disc portion facing downward. Provided above the lower mold,
The wheel has a flat lower surface that fits loosely in an outer peripheral ring of the same diameter as the final product, a claw portion that projects downward at the center of the lower surface, and an outer peripheral surface that curves upward from the lower surface. Direction, and lowers the upper die having a shoe that can be expanded outward in the radial direction and lowers the flat portion of the disc portion of the wheel between the lower surface of the upper die and the upper surface of the lower die. While pressing in the direction perpendicular to the portion, the outer peripheral surface of the shoe is engaged with the curved portion and the cylindrical portion of the disc portion, and the claw portion of the shoe is engaged with the hub hole of the flat plate portion of the disc portion. The flatness of a work having a flat plate-shaped portion, which expands the shoe radially outward, presses the rim portion against the outer peripheral ring, deforms the wheel to a plastic region and corrects the shape to a final product shape. Correction method.

(2) A disk portion having a flat plate-shaped portion having a hub hole at the center and a curved portion having the flat portion and a cylindrical portion having the curved portion, and a flange at one end. An annular rim portion is welded and joined at the cylindrical portion of the disc portion to form a wheel having a diameter slightly smaller than that of the final product, and the wheel has a flat upper surface with the disc portion facing down. While setting on the mold,
It is loosely fitted in the outer ring having the same diameter as the final wheel product, which is provided above the lower die, and has a flat lower surface, a claw portion projecting downward at the center of the lower surface, and a curved upper surface from the lower surface. The upper die having an outer peripheral surface that extends and a flange pressing portion that extends outward in the radial direction from the upper portion of the outer peripheral surface, is divided in the circumferential direction, and includes a shoe that can expand outward in the radial direction, is lowered, The flange portion of the rim portion of the wheel is clamped between the upper surface of the ring and the lower surface of the flange pressing portion in a direction perpendicular to the flange portion, and the disc portion of the wheel is interposed between the lower surface of the upper mold and the upper surface of the lower mold. While sandwiching the flat plate-shaped portion of the shoe in a direction perpendicular to the flat plate-shaped portion, the outer peripheral surface of the shoe is engaged with the curved portion and the cylindrical portion of the disk portion, and the claw portion of the shoe is inserted into the hub hole of the flat plate-shaped portion. Radially engages the shoe by engaging the circumference Is expanded outward, against the rim portion to the peripheral ring, the wheel is deformed until the plastic region to correct the shape the final product shape, flat 担度 correcting method of a workpiece having a flat portion.

(3) A fixed lower die, an outer peripheral ring mounted on the lower die, and an upper die movable up and down with respect to the lower die. The upper mold includes a lower mold plate having a supporting upper surface, and the upper mold includes a cotter having a tapered surface, a shoe holder divided in the circumferential direction and expanded / contracted by the cotter, and divided in the circumferential direction to the shoe holder. The shoe has a shoe that is fixed and expands and contracts together with the shoe holder. Further, the shoe has a flat lower surface and a claw portion that projects downward from the lower surface. Posture correction device.

(4) A work having a flat plate-shaped portion having a hole in the center is set on a lower die having a flat upper surface, and has a flat lower surface and a claw portion projecting downward from the lower surface, The upper die, which is divided in the circumferential direction and has a shoe that can be expanded outward in the radial direction, is lowered, and the flat plate-shaped portion is formed between the lower surface of the upper die and the upper surface of the lower die in a direction perpendicular to the flat plate-shaped portion. While pressing it, the claw portion of the shoe is engaged with the inner circumference of the hole of the flat plate portion to expand the shoe outward in the radial direction, and the work is deformed to the plastic region. A method for correcting the flatness of a work that has.

(5) A flat plate-shaped portion having a hole at the center, a curved portion connected to the outer peripheral portion of the flat plate-shaped portion, and a cylindrical portion connected to the curved portion and extending in a direction substantially perpendicular to the flat plate-shaped portion. The workpiece is set on the lower die having a flat upper surface with the flat upper surface facing downward, and the flat lower surface, the claw portion projecting downward at the center of the lower surface, and the upward bending from the lower surface. The upper mold having a shoe that has an outer peripheral surface that extends in the circumferential direction and is divided in the circumferential direction and that can be expanded outward in the radial direction, is lowered, and the work is interposed between the lower surface of the upper mold and the upper surface of the lower mold. While pressing the flat plate-shaped portion of the shoe in a direction perpendicular to the flat plate-shaped portion, the outer peripheral surface of the shoe is engaged with the curved portion and the cylindrical portion of the work, and the claw portion of the shoe is fixed to the flat-shaped portion of the work. Engage with the inner circumference of the central hole to expand the shoe radially outward A flatness correction method for a work having a flat plate-shaped portion, which deforms the work to a plastic region.

[0015]

In the flatness correcting method for a work having a flat plate-shaped portion and the apparatus therefor according to the present invention, the flat plate-shaped portion of the work is clamped in the direction perpendicular to the flat plate-shaped portion while the surface of the flat plate-shaped portion is pressed. An expanding force acting radially outward from at least the inner peripheral side is deformed inwardly to be deformed to a plastic region, and flatness is corrected. By applying a load in both the plate thickness direction and the radial direction in this way, it is possible to achieve a flatness that is significantly smaller than the conventional press load, has a higher load than the conventional press, and is easily formed. Is corrected.

[0016]

Preferred embodiments of the present invention will be described below with reference to the drawings. The first embodiment relates to a wheel straightening method and apparatus and is described in FIG. The second embodiment relates to a method of straightening a flat work, and FIG.
Explained. The third embodiment relates to a method of straightening a dish-shaped work and is described in FIG.

First Embodiment FIG. 1 shows an apparatus for carrying out straightening of a wheel. Reference numeral 100 denotes a wheel as a work having a flat plate portion. The wheel 100 comprises a welded joint between a rim portion 110 and a disc portion 120, and 130 indicates a welded portion.

The rim portion 110 is annular and has a flange 112 at one end and a gutter portion 114 at the other end. Another flange (not shown) is attached to the gutter portion 114. Tires (not shown) are attached to the rim portion 110. The radial load from the tire is received by the bead seat portion 116 of the rim, and the lateral load from the tire is received by the flange 112. It is necessary to set the radial dimension of the rim bead seat portion 116 within the standard value in order to reduce the vertical shake during traveling of the vehicle, and the wheel axial dimension of the flange 112 in order to reduce the horizontal shake. Must be set within the standard value.

The disk portion 120 has a flat plate-shaped portion 124 at the center for convenient connection of two wheels back to back like a truck rear wheel.
A hub hole 122 is bored in the center of 4. Minimize the deformation when attached to the wheel axle and tightened with bolts,
In order to eliminate the brake judder, the disc section 120
It is necessary to eliminate the undulations of the flat plate-shaped portion 124 and to flatten it. The disk portion 120 further includes the flat plate portion 12
The curved portion 126 has a curved portion 126 and the cylindrical portion 128 has a curved portion 126. Disc part 120 and rim part 1
10 is welded and joined at the end of the cylindrical portion 128.

Before being straightened, the wheel 100 is manufactured so that its radial dimension is slightly smaller than the final product shape (smaller by about 0.5 mm). Therefore, when the wheel 100 is pressed against the outer peripheral ring having the same inner diameter as the final wheel product, the wheel 100 is placed in the plastic region.

The straightening device 2 generally comprises a fixed lower mold 10
And the outer ring 20 attached to the lower mold 10 and the lower mold 1
And an upper mold 30 that is vertically movable above 0.

The lower mold 10 has a lower mold body 12 fixed on the bed of the press, and a lower mold plate 14 replaceably mounted on the lower mold body 12. The upper surface 16 of the lower mold plate 14 is a straight flat bearing surface that extends horizontally. The lower die plate 14 and the lower die main body 12 are provided with holes 18 at their central portions so that they do not interfere with each other when a part of the upper die is lowered.

The outer peripheral ring 20 is fixed on the lower mold 10. The inner diameter of the outer peripheral ring 20 is the same as the outer diameter of the final product shape of the wheel 100. Outer ring 20
May be composed of a single ring that is not cut in the circumferential direction, or may be a ring formed by combining elements that are divided in the circumferential direction. When divided into a plurality of pieces in the circumferential direction, by making each element movable in the radial direction, it becomes convenient to remove the work from the outer peripheral ring after forming the work.

The outer peripheral ring 20 has a disc curved portion 126.
The curved portion receiving portion 22 against which the rim portion 110 is pressed, the rim central portion receiving portion 24 that receives a portion from the rim bead seat portion 116 to the gutter portion 114 of the rim portion 110, and the flange receiving portion that receives the side surface of the flange 112 of the rim portion 110. It has a part 26. The flange receiving portion 26 has an upper surface 28.

The upper die 30 has a cotter 32, a shoe holder 34, and a shoe 36. The upper mold 30 further includes a spring 38, a spring seat 40, and an adjustment liner 42.
And a shoe holder hooking portion 44 and a slide member 46.

The cotter 32 has a tapered surface whose diameter decreases toward the lower die, and when the upper die 30 descends, the shoe holder 3
Expand 4 Between the cotter 32 and the shoe holder 34, a slide member 4 for ensuring a smooth slide is provided.
6 is interposed, and the slide member 46 is replaced when worn. When the upper mold 30 descends, the lower end of the cotter 32 projects into the hole 18 of the lower mold 10 without interference.

The shoe holder 34 is divided into a plurality of holder elements in the circumferential direction, for example, 6 in the circumferential direction. The shoe holder 34 and the cotter 32 are slidable along the tapered surface, and are expanded and contracted by the relative vertical movement of the cotter 32. A spring 48 is wound around the shoe holder 34 in the circumferential direction, and when the cotter 32 moves up relative to the shoe holder 34, the shoe holder 34 contracts due to the force of the spring 48. The spring 48 is a compression spring wound in a coil around an axis extending in the circumferential direction of the shoe holder.

The shoe 36 is divided into a plurality of shoe elements in the circumferential direction, and the number of the shoe elements is the same as that of the shoe holder 34. Each shoe element is bolted to each holder element so that the shoe 36 expands and contracts as the shoe holder 34 expands and contracts. When the size of the work to be molded changes, the shoe 36 is replaced with another shoe.

The shoe 36 has a flat lower surface 50, a claw portion 52 projecting downward from the lower surface 50, and an outer peripheral surface 54 that curves upward from the outer peripheral portion of the lower surface 50. The outer peripheral surface 54 includes a curved portion 56 that extends along the lower surface 50 and the curved portion 5
6 has a cylindrical surface 58 that hangs at the upper end. At the upper end of the outer peripheral surface 54, the shoe 36 has a flange pressing portion 60 that protrudes outward in the half direction. The flange pressing portion 60 has a lower surface 62.

The claw portion 52 of the shoe 36 is the outer peripheral surface 6 of the claw portion.
Holds 4. The claw portion 52 is fitted into the hub hole 122 of the disc portion 120 of the wheel 100 when the upper die 30 is lowered, and when the shoe 36 is opened, the outer peripheral surface 6 of the claw portion 52 is inserted.
4 is the hub hole 12 of the disc portion 120 of the wheel 100.
2 The inner peripheral surface is pushed outward in the radial direction to deform the disk portion 120 to the plastic region. At this time, the lower surface 50 of the shoe 36 and the upper surface 16 of the lower mold plate 14 press the flat plate portion 124 of the wheel disc portion 120 in a direction perpendicular to the flat plate portion 124, and the adjustment of the timing is performed by the adjustment liner 42. By changing the thickness and number of sheets.

When the lower surface 50 of the shoe 36 presses the flat plate-shaped portion 124 of the wheel disk portion 120, the lower surface 62 of the flange pressing portion 60 of the shoe 36 is also the wheel 10.
No. 0 rim flange 112 is axially pressed between the rim flange 112 and the outer peripheral ring 20, and the outer peripheral surface 54 of the shoe 36 is also the disk curved portion 126 and the rim portion 110 of the wheel 100.
The shape of the shoe 36 is determined so as to push radially outwardly against the outer peripheral ring 20.

Next, a wheel straightening method for straightening the shape of the wheel 100 using the apparatus shown in FIG. 1 will be described. First, the wheel 100, which has a slightly smaller diameter than the final product
To form. However, the wheel 100 has a disc portion 1
The disc portion 120 includes a flat plate-shaped portion 124 having a hub hole 122 in the center, a curved portion 126, and a cylindrical portion 128. In this state, the rim portion 110 of the wheel 100 is
Is not a perfect circle, and the flat plate-shaped portion 1 of the disk portion 120
24 has a swell.

Next, as shown in the right half of FIG. 1, the wheel 100 is set on the lower mold plate 14 of the lower mold 10 with the disk portion 120 facing down, and the wheel 100 is set in the outer ring 20. Fit. Here, the lower mold plate 14
The upper surface 16 of the outer peripheral ring 20 extends horizontally, and the inner diameter of the outer peripheral ring 20 is matched with the outer diameter of the final product of the wheel 100. When the upper mold 30 is not lowered in the fitted state, there is a gap d between the wheel 100 and the outer peripheral ring 20.

Next, the upper die 30 is lowered. In this lowering step, first, the rim flange portion 112 is pinched by the flange pressing portion 60 of the shoe 36 and the outer peripheral ring 20, and the disk portion flat plate portion 124 is placed on the lower surface 5 of the shoe 36.
0 and the upper surface 16 of the lower die plate 14 in a direction perpendicular to the plate surface, and at the same time, the rim portion 110, the disk curved portion 126, and the cylindrical portion 128 are kept in a very small amount (diameter) within the elastic deformation range of the rim. 0.5 mm). As a result, the rim portion 110 and the disk portion 120, which are initially one-sided because they are not perfect circles, simultaneously move to the shoe 3
Adhere to the entire surface of 6. As a result, a perfect circle is formed within the elastic limit. In this state, a small gap is left between the wheel 100 and the outer ring 20.

In this state, the flat plate portion 12 of the disk
While pressing 4 in a direction perpendicular to the plate surface, the upper die 30 is further lowered by a minute amount to expand the wheel 110 by about 0.5 mm in diameter, and the rim portion 110 and the disk portion 120 are radially radially outward. Deform to the plastic region. At this time, the outer peripheral surface 64 of the claw portion 52 of the shoe 36 engages with the inner peripheral surface of the hub hole 122 to expand the disk portion flat plate portion 124 from the inner peripheral side. At the same time, the shoe 36 also spreads the curved portion 126 and the cylindrical portion 128 of the disk portion 120.

By the above plastic deformation, the wheel 100
Is pressed against the inner peripheral surface of the outer peripheral ring 20. And
Wheel 100 is shaped to its final shape.

When shaping is completed, the upper die 30 is lifted by the press ram, the shoe holder 34 is reduced in diameter by the spring 48, and the shoe 36 is also reduced in diameter due to the reduced diameter of the shoe holder 34. After that, the wheel 100 is taken out from the outer peripheral ring 20. To facilitate removal, the outer peripheral ring 20 may be divided in the circumferential direction so as to have a larger diameter when the wheel is removed.

In the above correction, the flat plate portion 124 of the disk portion is simultaneously subjected to the outward force in the radial direction and the clamping force perpendicular to the plate surface. Moreover, the radial outward force is applied at least from the inner circumference of the hub hole. Due to this force, the disk-shaped flat plate portion 124 is deformed to the plastic region. With this correction, the flatness of the flat portion 124 of the disk portion was significantly improved from the conventional level of about 0.5 mm to 0.1 mm or less. Moreover, the pressing force is about 250 TON, which is drastically reduced as compared with the conventional pressing force of about 1200 TON or more required to make the swell of 0.5 mm. A waviness of 0.1 mm or less has a high precision that is difficult to maintain due to a change in stress balance thereafter even if it is temporarily obtained by cutting, and according to the present invention, such a high precision flatness is achieved by molding. The degree can be corrected.

Moreover, the flat portion 124 can be corrected at the same time as the shape of the entire wheel is corrected, so that vertical shake and shake can be reduced and brake judder can be suppressed.

Second Embodiment Of the above-described wheel straightening, flatness correction of the flat plate portion of the disk can be used for flatness correction of a flat plate having a hole in the center other than the wheel. FIG. 2 shows such a case.

In FIG. 2, parts to which the apparatus and method described with reference to FIG. 1 can be applied are assigned the same reference numerals as in FIG. In FIG. 2, only parts different from FIG. 1 will be described.

A work 120A having a flat plate-shaped portion shown in FIG.
In the flatness straightening method of No. 1, first, the hole 122 is formed in the central portion.
A flat plate-shaped work 120A having an A
It is set on the lower mold plate 14A having.

Next, the flat lower surface 50A and the lower surface 50A
The upper die having the claw portion 52A projecting downward from is divided in the circumferential direction and provided with the shoe 36A capable of expanding outward in the radial direction is lowered.

The flat plate-shaped work 12 is placed between the lower surface 50A of the upper die shoe 36A and the upper surface 16A of the lower die plate 14A.
While clamping 0A in the direction perpendicular to the plate surface, the claw portion 52A of the shoe 36A is engaged with the hole 122A of the work 120A,
By expanding the shoe 36A, the work 120A
Deform to the plastic range. Even in this case, the waviness can be corrected with high accuracy and a flatness can be obtained with a small pressing force as compared with the related art.

Third Embodiment The third embodiment relates to the case where the present invention is applied to a dish-shaped work (molding of a single disk) having a flat plate-shaped portion with a hole. In FIG. 3, parts to which the apparatus and method described in FIG. 1 can be applied are assigned the same reference numerals as in FIG. In FIG. 3, only parts different from FIG. 1 will be described.

In FIG. 3, the work 120B has a flat plate-shaped portion 124B having a hole 122B in the central portion, a curved portion 126B corresponding to the flat portion 124B, and a cylindrical portion 128B connected to the curved portion 126B. This work 120B is made slightly smaller than the final product, and is set on the lower mold plate 14B having the flat upper surface 16B with the flat plate-shaped portion 124B facing downward.

Next, the flat lower surface 50B, the claw portion 52B projecting downward from the flat lower surface 50B, and the outer peripheral surface 56B extending from the outer peripheral portion of the lower surface 50B are divided in the circumferential direction and can be expanded outward in the radial direction. The upper mold provided with the shoe 36B is lowered.

Next, the outer peripheral surface 56B of the shoe 36B is clamped between the lower surface 50B of the upper die 36B and the upper surface 16B of the lower die while sandwiching the work flat plate portion 124B in the face-to-face direction with the curved surface 126B of the work and the curved surface 126B of the work. While engaging with the cylindrical portion 128B, the shoe claw portion 52B is attached to the work center hole 12
By engaging the shoe 2B with the shoe 36B and expanding the shoe 36B outward in the radial direction, the workpiece 120B is deformed to the plastic region. Even in this case, a small pressing force can be applied to the waviness of the flat plate portion of the dish-shaped work, and the flatness can be obtained.

[0049]

In any of the inventions of the claims, since the expanding force is applied to the work at least from the inner peripheral hole of the work while the flat plate-like portion of the work is clamped in the direction perpendicular to the plate surface,
Compared to the conventional case where a pressing force is applied in the direction perpendicular to the plate surface, the flatness of the work flat plate portion can be more accurately obtained with a small pressing force. Moreover, because it is formed, it is more efficient than cutting.

[Brief description of drawings]

FIG. 1 is a sectional view of an apparatus for carrying out a flatness correcting method for a work having a flat plate-shaped portion according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an apparatus for carrying out a flatness correction method for a work having a flat plate-shaped portion according to a second embodiment of the present invention.

FIG. 3 is a sectional view of an apparatus for carrying out a flatness correcting method for a work having a flat plate-shaped portion according to a third embodiment of the present invention.

[Explanation of symbols]

 10 Lower Mold 14 Lower Mold Plate 16 Upper Surface 20 Outer Ring 30 Upper Mold 32 Cotter 34 Shoe Holder 36 Shoe 38 Spring 50 Lower Surface 52 Claws 54 Outer Surface 60 Flange Pressing Part 62 Lower Surface 100 Wheel 110 Rim Part 120 Disk Part 122 Hub Hole 124 Flat plate part 126 Curved part 128 Cylindrical part

Claims (5)

[Claims] 1. A disk portion having a flat plate-shaped portion having a hub hole at the center and a curved portion having the flat portion and a cylindrical portion having the curved portion, and an annular rim portion. The disc portion is welded and joined by a cylindrical portion to form a wheel having a diameter slightly smaller than that of the final product, and the wheel is set on the lower die having a flat upper surface with the disc portion facing downward, It is loosely fitted in the outer ring having the same diameter as the final wheel product, which is provided above the lower mold, and has a flat lower surface, a claw portion projecting downward at the center of the lower surface, and a curved upper surface from the lower surface. A lower die having a shoe having an outer peripheral surface extending and being circumferentially divided and capable of expanding outward in the radial direction, and lowering the upper die lower surface and the lower die upper surface to the disk of the wheel. While pinching the flat plate-shaped portion of the portion in a direction perpendicular to the flat plate-shaped portion, The outer peripheral surface of the shoe is engaged with the curved portion and the cylindrical portion of the disc portion, and the claw portion of the shoe is engaged with the hub hole of the flat plate portion of the disc portion to expand the shoe radially outward. Opening, pressing the rim portion against the outer peripheral ring, deforming the wheel to a plastic region to correct the shape into a final product shape. A flatness correcting method for a work having a flat plate-shaped portion. 2. A disk portion having a flat plate-shaped portion having a hub hole at the center and a curved portion having the flat plate-shaped portion and a cylindrical portion having the curved portion on the outer periphery, and a ring having a flange at one end. A rim portion of the disc is welded to the cylindrical portion of the disc portion to form a wheel having a diameter slightly smaller than that of the final product, and the wheel is a lower mold having a flat upper surface with the disc portion facing downward. The lower surface, which is set above, is loosely fitted in the outer ring having the same diameter as the final wheel product and is provided above the lower die, and the flat lower surface and the lower surface projecting claw portion and the lower surface. An upper die having an outer peripheral surface that curves upward from the outer peripheral surface and a flange pressing portion that extends outward in the radial direction from the upper portion of the outer peripheral surface, is divided in the circumferential direction, and has a shoe that can be expanded outward in the radial direction Lower the upper surface of the outer ring and the flan The flange portion of the rim portion of the wheel is clamped between the lower surface of the pressing portion in a direction perpendicular to the flange portion, and a flat plate-shaped portion of the disk portion of the wheel is provided between the lower surface of the upper mold and the upper surface of the lower mold. While sandwiching the shoe in a direction perpendicular to the flat plate portion, the outer peripheral surface of the shoe is engaged with the curved portion and the cylindrical portion of the disk portion, and the claw portion of the shoe is engaged with the inner periphery of the hub hole of the flat plate portion. To expand the shoe radially outward, press the rim portion against the outer peripheral ring, and deform the wheel to a plastic region to correct the shape into a final product shape. A method for correcting the flatness of a work that has. 3. A fixed lower die, an outer peripheral ring mounted on the lower die, and an upper die movable up and down with respect to the lower die, wherein the lower die is flat. A lower mold plate having an upper surface, and the upper mold includes a cotter having a tapered surface, a shoe holder that is divided in the circumferential direction and expanded / contracted by the cotter, and is fixed to the shoe holder that is divided in the circumferential direction. And a shoe that expands and contracts together with the shoe holder, and the shoe has a flat lower surface and a claw portion projecting downward from the lower surface. A flatness correction device for the work that it has. 4. A work having a flat plate-shaped portion having a hole in the center thereof is set on a lower die having a flat upper surface, and has a flat lower surface and a claw portion projecting downward from the lower surface. Direction, and lowers the upper die having a shoe that can be expanded outward in the radial direction, so that the flat plate-shaped portion is perpendicular to the flat plate-shaped portion between the lower surface of the upper mold and the upper surface of the lower mold. While pinching, the claw portion of the shoe is engaged with the inner circumference of the hole of the flat plate portion to expand the shoe radially outward, and the work is deformed to a plastic region. A flatness correction method for a work having a flat plate portion. 5. A flat plate-shaped portion having a hole in a central portion, a curved portion formed along the outer peripheral portion of the flat plate-shaped portion, and a cylindrical portion formed along the curved portion and extending in a direction substantially perpendicular to the flat plate-shaped portion. The work is set on the lower die having the flat upper surface with the flat upper surface facing downward, and the flat lower surface, the claw portion projecting downward at the center of the lower surface, and the upward bending from the lower surface. The upper die having a shoe that has an outer peripheral surface that extends in the circumferential direction and is divided in the circumferential direction and that can be expanded outward in the radial direction, and lowers the upper die between the lower surface of the upper die and the upper surface of the lower die. While pressing the flat plate-shaped portion in a direction perpendicular to the flat plate-shaped portion, the outer peripheral surface of the shoe is engaged with the curved portion and the cylindrical portion of the work, and the claw portion of the shoe is placed at the center of the flat-plate portion of the work. Engage the inner circumference of the hole in the section to expand the shoe radially outward. Rights 担度 correcting method of a workpiece having a flat portion, characterized in that, deforming the workpiece to the plastic region.