JPH0576971A - Formation of inner peripheral wall for press-inserting bearing in pulley made of sheet metal - Google Patents

Abstract

PURPOSE:To finish uniformly with high accuracy the inside diameter of an inner peripheral wall for the press-inserting a bearing in a pulley made of a sheet metal. CONSTITUTION:The inner peripheral wall corresponding part 3 is formed by drawing a flat plate material at its center part, an inner die 100 is covered with the material forming the inner peripheral wall corresponding part 3 and the inner peripheral wall corresponding part 3 of the material covering the inner die 100 is drawn to finish uniformly with high accuracy the inside diameter of the inner peripheral wall 10.

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 a bearing press-fitting inner peripheral wall in a sheet metal pulley.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 2-20345 discloses a sheet metal pulley. The sheet metal pulley described in this publication uses a flat plate-shaped material made of a metal plate as a starting material, and squeezes the flat plate-shaped material to form a bottom wall-corresponding part and a peripheral wall-corresponding part. It is manufactured by a method of folding back a predetermined portion of the portion corresponding to the peripheral wall to form an inner peripheral wall and an outer peripheral wall. Then, in the molding step, the inner peripheral wall corresponding portion and the outer peripheral wall corresponding portion are formed by folding back the peripheral wall corresponding portion with two molds each having a molding surface having a uniform diameter, and the inner peripheral wall corresponding portion is treated. And the inner wall.

[0003]

However, according to the conventional method, since the inner peripheral wall made by handling the inner peripheral wall corresponding portion has a large plate thickness, it is difficult to make the inner diameter uniform, that is, precise inner diameter machining. In some cases, the inner surface of the inner peripheral wall is formed with a loose curved surface, or the inner surface of the inner peripheral wall becomes larger as the distance from the bottom wall increases. If the inner diameter of the inner peripheral wall is not uniform as described above, the bearing is pressed into the inner peripheral wall and the pulley is misaligned, or the bearing cannot be fitted to a predetermined position. Things happen.

The present invention has been made in view of the above circumstances, and the formation of the inner peripheral wall for press-fitting the bearing in the pulley made of sheet metal capable of uniformly finishing the inner diameter of the inner peripheral wall into which the bearing is fitted, that is, precision finishing. The purpose is to provide a method.

[0005]

According to a method of forming an inner peripheral wall for press-fitting a bearing in a sheet metal pulley according to the present invention, a central portion of a plate-shaped material is squeezed to form an inner peripheral wall corresponding portion, and the inner die is covered. The inner peripheral wall for press-fitting the bearing is formed by handling the portion corresponding to the inner peripheral wall of the material.

[0006]

According to the method of forming the bearing press-fitting inner peripheral wall of the sheet metal pulley of the present invention, the central portion of the flat plate-shaped material is squeezed, so that the plate thickness of other portions is not made too thin.
The plate thickness of the portion corresponding to the inner peripheral wall can be reduced more effectively. By handling the portion corresponding to the inner peripheral wall by reducing the plate thickness of the portion corresponding to the inner peripheral wall, the inner peripheral wall into which the bearing is fitted. The inner diameter of can be precisely formed.

[0007]

EXAMPLES Next, a method of manufacturing a sheet metal poly-V pulley adopting an example of the present invention will be described item by item for each step. As the flat material (not shown) as a starting material, the same thickness as that required for the outer peripheral wall 13 provided with the poly V groove 15 in the sheet metal poly V pulley to be manufactured is used. There is.

A. First Drawing Step This step is a step of forming a bottom wall-corresponding portion 1 and a peripheral wall-corresponding portion 2 by squeezing the central portion of a flat plate material, which is a starting material, with an inner die 100 and an outer die 200 as shown in FIG. . In the peripheral wall equivalent part 2, an inner peripheral wall equivalent part 3 which becomes an inner peripheral wall 10 for bearing press fitting of a sheet metal poly V pulley to be manufactured, and a poly V protruded outward from the tip of the inner peripheral wall equivalent part 3. An outer peripheral wall-corresponding portion 4 serving as the outer peripheral wall 13 provided with the groove 15 is provided. By going through this first drawing step, the bottom wall equivalent portion 1
The inner peripheral wall corresponding portion 3 is thinned. Specifically, when a flat plate-shaped material having a wall thickness of 2.8 mm is used, the bottom wall corresponding portion 1 has a wall thickness of about 2.6 mm, and the inner peripheral wall corresponding portion 3 has a thickness of 1.8 to 2.1.
The thickness is reduced to about mm. In many cases, the wall thickness of the outer peripheral wall equivalent portion 4 does not change. The drawing depth is 15.1 mm
Is set to.

B. Drilling Step In this step, as shown in FIG. 2, the inner die 101 and the punch 201 are used to open a hole 5 in the center of the bottom wall corresponding portion 1. The hole 5 formed in this process is to be machined into the shaft hole 16 in the subsequent process, and the inner diameter of the shaft hole 16 is 3 mm.
When 1.0 mm is required, the inner diameter of the hole portion 5 may be set to 15.7 mm, which is about half the inner diameter. 6 is a scrap generated by drilling, and this scrap 6 is punched from the thinned bottom wall equivalent portion 1, and by punching out the hole portion 5 which is about half the size of the shaft hole 16. Since it has occurred, the amount is extremely small.

C. Second drawing step In this step, the bottom wall equivalent part 1 and the inner peripheral wall equivalent part 3 of the material (hereinafter referred to as a hat-shaped material W) that has undergone the perforation step described in FIG. And the outer mold 202 are used to further squeeze, and thereby the hole 5 of the bottom wall equivalent portion 1
Is a step of expanding the diameter. In the hat-shaped material W that has undergone the second drawing process, the bottom wall equivalent portion 1 and the inner peripheral wall equivalent portion 3 are continuous via the radiused portion 7 having a relatively large radius of curvature, and the radiused portion 7 is meat. The thickness is reduced to about 1.6 to 1.7 mm. Further, the inner peripheral wall equivalent portion 3 is 1.6 to
The thickness is reduced to about 1.7 mm.

D. Handling Step This step is a step of further narrowing down the inner peripheral wall equivalent portion 3 narrowed down in the second narrowing step to adjust its shape. Therefore, this handling step can be said to be the third drawing step performed after the second drawing step, and the first handling step shown in FIG. 4 and the second handling step shown in FIG. 5 are performed. Contains.
By passing through this step, the corner portion 8 of the hat-shaped material W is formed at the boundary portion between the bottom wall-corresponding portion 1 and the inner peripheral wall-corresponding portion 3 at a right angle or near a right angle. That is, in the first handling step of FIG. 4, the radius of curvature of the rounded portion 7 shown in FIG. 3 is slightly reduced by the inner die 103 and the outer die 203, and then,
By performing the second handling step of FIG. 5, the rounded portion 7 of the inner mold 104 and the outer mold 204 is shaped as a corner portion 8 which is closer to a right angle, and at the same time, the bottom wall equivalent portion 1 is formed on the bottom wall 9. The inner peripheral wall equivalent portion 3 is formed on the inner peripheral wall 10.

The inner mold 104 used in the second handling step is
A molding surface 105 having a uniform outer diameter is provided, and the molding surface 105 of the inner mold 104 is covered with the inner peripheral wall corresponding portion 3 of the hat-shaped material W. In addition, the outer mold 204 corresponding to the inner mold 104
Means that the inner diameter of the pressing surface 205 with respect to the inner peripheral wall equivalent portion 3 of the hat-shaped material W covered by the inner mold 104 is the boundary portion of the inner peripheral wall equivalent portion 3 with the bottom wall equivalent portion 1, that is, the inner peripheral wall equivalent portion 3. The diameter increases as it moves away from the portion that presses the base end portion (corresponding to the corner portion 8) in the axial direction. When the inner peripheral wall 10 is formed by handling the inner peripheral wall equivalent part 3 of the hat-shaped material W covered with the inner mold 104 by using the outer mold 204, the formed inner peripheral wall 10 has a corner which is the base end thereof. The thicker it gets from the part 8, the thicker it becomes. That is, in the hat-shaped material W that has undergone the second handling step, the corner portion 8 and the inner peripheral wall 10 in the immediate vicinity thereof have a wall thickness of about 1.7 mm, and the portion immediately near the tip of the inner peripheral wall 10 has a wall thickness of about 2.1 mm. Become. Then, in this way, it was confirmed that even if the hat-shaped material W was released from the mold, the inner diameter of the inner peripheral wall 10 was finished uniformly. Therefore, when the bearing is press-fitted into the inner peripheral wall 10, a misalignment between the bearing and the pulley does not occur, and the bearing can be surely inserted into a predetermined position. In FIG. 5, the difference in the wall thickness of each axial portion of the inner peripheral wall 10 is exaggerated.

E. Finishing process of the portion corresponding to the outer peripheral wall In this process, as shown in FIG.
7 is a step of cutting and removing the outer peripheral edge of the outer peripheral wall corresponding portion 4. 11 is scrap.

F. Reverse drawing step In this step, as shown in FIG. 7, the outer peripheral wall equivalent portion 4 of the hat-shaped material W put on the inner dies 108 and 109 and sandwiched between the outer dies 209.
The outer peripheral wall 1 is concentric with the inclined annular portion 12 and the inner peripheral wall 10 by being folded back at.
3 is a step of forming.

G. Bulge step In this step, as shown in FIG. 8, the inner die 110 is covered with the hat-shaped material W which has undergone the reverse drawing step described in FIG. 7, and the tip of the outer peripheral wall 13 is attached to the supporting surface 111 provided in the inner die 110. This is a step of supporting the surface and pressing the annular portion 12 from the state by the outer die 210 to expand the boundary portion between the outer peripheral wall 13 and the annular portion 12, that is, the root portion of the outer peripheral wall outward. The outer peripheral wall 13 of the hat-shaped material W that has undergone this step is formed such that the tip side portion is smaller in diameter than the root portion, and in some cases it is simultaneously thickened.

H. Ear portion forming step This step is a step of forming a single-layer annular ear portion 14 at the intersection of the outer peripheral wall 13 and the annular portion 12. This step is performed as follows. That is, as shown in FIG. 9, the rotating inner molds 112, 113 are covered with the hat-shaped material W that has undergone the bulge process and sandwiched, and at the same time, the rotating inner molds 112, 11
The upper and lower clamping surfaces 114 and 115 of the outer peripheral wall 13
Cling to. Rotate the hat-shaped material W in this way
Covering 12, 113, the outer peripheral wall 13 and the rotating inner mold 112
A space S is formed between and.

While rotating the outer rotating mold 213 in this state, as shown in FIG. 10, the root portion of the outer peripheral wall 13 is pressed against the inner rotating mold 112 side to deform so that the space S disappears. The ear forming protrusion 214 provided on the outer rotating mold 213 from the outside so as to divide the root portion into two.
And bite into. By doing so, the root portion of the outer peripheral wall 13 having the constricted tip end held between the holding surfaces 114, 115 of the inner rotating dies 112, 113 is deformed radially outward due to the deformation when the space S is eliminated. The amount of material flowing to the outer peripheral wall 13 increases, and the amount of protrusion of the ear portion 14 from the outer peripheral wall 13 becomes sufficiently large. The outer peripheral wall 13 that has undergone this process is thickened to a thickness of about 2.9 mm.

I. Poly V Groove Forming Step This step is a step of forming the poly V groove 15 on the outer peripheral wall 13. In this step, as shown in FIG. 11, FIG. 12 or FIG. 13, the hat-shaped material W is sandwiched between the inner rotating dies 112 and 113, and the outer wall 13 has a poly V groove 1 made up of a plurality of V groove groups.
5 is formed by rolling and forming the poly V groove 15, but the poly V groove 15 is formed by the preliminary poly V groove forming step and the preliminary poly V groove forming step more than the case of forming by one rolling. It is preferable that the poly V groove of the outer peripheral wall 13 that has been subjected to the rolling is further subjected to rolling, and a finishing step of finishing the depth and pitch thereof as required is performed by plural times of rolling forming.

This step is carried out by rotating the inner mold 11 as shown in FIG.
The molding surface 116 of No. 2 and the molding surface 216 of the outer rotary mold 215 both have valleys and peaks alternately and are formed in a shape that can be meshed with each other, or FIG.
1 and FIG. 12, the molding surface 116 of the inner rotating mold 112 is a flat surface in the vertical direction and the molding surface 216 of the outer rotating mold 215.
What is formed may be used, what is formed in the uneven | corrugated surface which has a valley part and a peak part alternately. When the method of FIG. 13 is adopted, a sheet metal poly V pulley having a poly V groove 15 on the outer surface side and an outer peripheral wall 13 having an uneven inner surface is manufactured. When the method of FIGS. 11 and 12 is adopted, a sheet metal poly V pulley having a poly V groove 15 on the outer surface side and an outer peripheral wall 13 whose inner surface is straight in the vertical direction is manufactured.

J. Centering Step This step is a step of centering the inner peripheral wall 10 and the outer peripheral wall 13 by using the inner mold 117 and the outer mold 217 as shown in FIG.

K. Axial hole finishing step This step is performed in the inner die 118 and punch 218 as shown in FIG.
This is a step of cutting and removing the peripheral edge portion of the hole portion 5 whose diameter has been expanded by using and to finish the shaft hole 16. 17 is scrap.

In the embodiment described above, the shaft hole 16 formed by expanding the diameter of the hole portion 5 may have the same inner diameter as the inner diameter of the inner peripheral wall 10. That is, it is possible to manufacture a sheet metal pulley in which the opening portion of the inner peripheral wall 10 serves as a shaft hole without the bottom wall 9.

In this embodiment, the sheet metal poly V pulley for the poly V belt has been described, but the present invention can also be applied to the V pulley for the V belt.

[0024]

According to the present invention, the inner diameter of the inner peripheral wall for press-fitting the bearing can be precisely processed, and the inner diameter of the inner peripheral wall can be made uniform. Therefore, the bearing can be securely fitted to the predetermined position so that the inner peripheral wall of the pulley is not misaligned with the pulley.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first drawing process.

FIG. 2 is an explanatory diagram of a drilling process.

FIG. 3 is an explanatory diagram of a second drawing process.

FIG. 4 is an explanatory diagram of a first handling step.

FIG. 5 is an explanatory diagram of a second handling step.

FIG. 6 is an explanatory diagram of a finishing process of a portion corresponding to the outer peripheral wall.

FIG. 7 is an explanatory diagram of a reverse drawing process.

FIG. 8 is an explanatory diagram of a bulge process.

FIG. 9 is an explanatory diagram of an ear portion forming process.

FIG. 10 is an explanatory diagram of an ear portion forming process.

FIG. 11 is an explanatory diagram of a poly V groove forming step.

FIG. 12 is an explanatory diagram of a poly V groove forming step.

FIG. 13 is an explanatory diagram of a poly V groove forming step.

FIG. 14 is an explanatory diagram of an alignment process.

FIG. 15 is an explanatory diagram of a shaft hole finishing process.

[Explanation of symbols]

 3 Inner wall equivalent part 10 Inner wall 100 Inner mold

Claims (1)

[Claims] 1. A flat plate-shaped material is squeezed at a central portion to form an inner peripheral wall equivalent portion, an inner peripheral wall equivalent portion is covered with an inner die, and an inner peripheral wall equivalent portion of the material is covered with the inner die. A method of forming a bearing press-fitting inner peripheral wall in a sheet metal pulley, comprising forming the bearing press-fitting inner peripheral wall by handling.