JPH05329568A - Manufacture of washer - Google Patents

Abstract

PURPOSE:To manufacture a flat washer having no shear droop by only punching by forming an excess metal in a peripheral edge part of a primary formed part by the gentle inclined surface of a punch in a primary punching process, and shearing the primary formed part in the opposite direction in a secondary punching process. CONSTITUTION:In a secondary punching process, a primary formed part 5 manufactured in a primary punching process is turned inside out and a face push punch 9 is allowed to pass through its core hole 4 so that an outside peripheral end edge part 18 of a primary formed part 5 being larger than the outside diameter of a shedder 10 gets on a shaving die 8, and the upper die is subjected to rolling reduction so that the outside peripheral end edge part 18 is cut down due to a fact that a shaving punch 13 is fitted into the shaving die 8 and shearing force in the opposite direction to the primary punching process works on the primary formed part 5. In such a way, since the shearing force in the opposite direction to the primary process is applied to the peripheral edge part of the primary formed part 5, a curvature of the excess metal part and the whole indentation is also corrected and as a result, the quality of a washer can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a washer (washer) by using a flat plate as a raw material and subjecting it to shear punching.

[0002]

2. Description of the Related Art Washers are generally manufactured by punching a flat plate with a shear punching machine such as a transfer press machine. However, in a method of manufacturing a washer in which a flat plate is sheared by a tool such as a die and a punch to perform a punching process, the surface of the material is pressed down when the tool is bitten, so that the so-called "drip part" is produced. Can be done. As a result, the washer, which is a product, has a sag d formed on the periphery thereof as shown in a slightly exaggerated manner in FIG. 6, and when the washer is used, the contact area with the lower surface of the bolt head is reduced and the washer is reduced. As a result, there is a possibility that the anti-loosening function may not be sufficiently obtained.

Therefore, it has been conventionally practiced to further flatten the surface by further cutting the washer manufactured by punching as described above, but since the cutting generally requires a long time, it is manufactured. There was a drawback that the cost was high.

[0004]

The method for manufacturing a washer according to the present invention is intended to solve the above-mentioned problems, and a plate-shaped material is punched by a punch having a gently-sloping surface with a constant width at the peripheral portion of the tip surface. The primary punching step of producing a primary molded product curved in a circular shallow dish shape by forming a surplus in the peripheral portion by punching, and the primary punching process by turning over the primary molded product is performed by shearing opposite to that of the primary punching process. It is characterized by comprising a secondary punching step of cutting off the outer peripheral edge portion of the primary molded product.

[0005]

In the primary punching process, a sloping surface of the punch forms a surplus in the peripheral edge of the primary molded product. In the secondary punching process, this surplus is formed by shearing the primary molded product in opposite directions. A washer with no sagging can be manufactured by supplementing the conventional "drip part" only by punching.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a core removing process, in which 1 is a die type and 2
Is a punch for punching into the die hole, 3 is the punch 2
1 shows a flat plate-shaped material in which a circular core hole 4 is punched out.

From the plate-shaped material 3 having the core hole 4 punched in the core-pressing step of FIG. 1, the primary-molded product 5 as shown in FIG. 3 is manufactured through the primary stamping step shown in FIG.

As shown in FIG. 2A, this punch 6
Is formed such that the peripheral edge constant width 7 of the tip surface is formed into a gently inclined surface,
The punch 6 is pierced into the die hole 16 as shown in FIG. 2 (b), and the plate-shaped material 3 is punched concentrically with the core hole 4 to form a surplus wall 17 at the peripheral edge thereof, which causes shearing force. A circular shallow dish-shaped primary molded product 5 curved to the side of the die hole 16 is manufactured.

Next, the secondary punching process shown in FIGS. 4A and 4B is started. The lower mold in the figure is the shaving die 8
Face press punch 9 and shedder 1 as product guide
0 is urged upward by a spring (not shown) to support the upper end of the surface pressing punch 9 so as to project from the upper surface of the shaving die 8, while the upper die is supported by the stripper bolt 11. A cylindrical shaving punch 13 is slidably provided in the stripper plate 12 thus formed, and a surface pressing punch 15 is fixed in the shaving punch 13 by a hanging bolt 14, and the lower end surface of the surface pressing punch 15 is It is formed in a shape that can match the tip of the surface pressing punch 9.

In the secondary punching step, however, the primary molded product 5 produced in the primary punching step is turned over and the result is shown in FIG.
As shown in (a), the surface pressing punch 9 is passed through the core hole 4 so that the outer peripheral edge portion 18 of the primary molded product 5 which is larger than the outer diameter of the shedder 10 rides on the shaving die 8 and the upper die is pressed down. Then, as shown in FIG. 4B, the shaving punch 13 is fitted into the shaving die 8 to exert a shearing force on the primary molded product 5 which is opposite to that in the primary punching step, and thereby the outer peripheral edge is formed. The part 18 is cut off.

In this way, by applying a shearing force to the peripheral edge of the primary molded product 5 in the direction opposite to the primary, the surplus part 17 is dented and the entire curvature is corrected, resulting in a flat washer as shown in FIG. Be done.

The punch 6 shown in this embodiment has a constant peripheral edge width 7 formed into a linear inclined surface.
This may be an arcuate inclined surface shape, and in short, the surplus thickness 17 necessary for the primary molded product 5 may be formed.

[0013]

As described above, according to the method for manufacturing a washer of the present invention, a flat washer having no sagging can be manufactured only by punching, the cost can be reduced, and the beneficial effect of improving the quality of the washer can be obtained. There is.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a centering step.

FIG. 2 is a vertical sectional view of a primary punching process.

FIG. 3 is a vertical cross-sectional view of a primary molded product.

FIG. 4 is a vertical sectional view of a secondary punching process.

FIG. 5 is a longitudinal sectional view of a washer manufactured by the manufacturing method of the present invention.

FIG. 6 is a vertical sectional view of a conventional washer.

[Explanation of symbols]

 3 Plate Material 5 Primary Molded Product 6 Punch 7 Peripheral Part Constant Width 10 Sheder 13 Shaving Punch 15 Face Push Punch 16 Die Hole 17 Extra Thickness 18 Peripheral Edge

Claims (1)

[Claims] 1. A primary molded product, which is curved in a circular shallow dish shape, in which a plate-shaped material is punched out by a punch having a peripheral surface of which a constant peripheral edge width is formed into a gentle slope to form a surplus in the peripheral edge. A primary punching step of manufacturing, and a secondary punching step of turning over the primary molded article and cutting off the outer peripheral edge of the primary molded article by shearing opposite to the primary punching step. Washer manufacturing method.