JP2000071043A - Plate thickness increasing method and equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cold-forge a part whose flange portion is provided with a boss, without causing piling of a material at a corner portion, by giving resistance to the flange portion of the material by inserting the mandrel in the hole of the material, pressing the boss top face of the material with the punch, pressing the flange face with the die, and providing the punch and the die in such a way that they can relatively move in the vertical direction. SOLUTION: A lower die is composed of a lower die 3 and a mandrel 4. An upper die is composed of an upper die 5 and a punch 6. The mandrel 4 is inserted in the hole of a material 1. When the slide of a press machine descends, the upper die 5 and the punch 6 are energized and moved down by a pin 8 for the upper die and a pin 7 for the punch, respectively. The material 1 increase in thickness to become a product 2 through the combined action of the lower die 3, the upper die 5, the punch 6, and the mandrel 4. It is desirable to provide the upper die 5 with a protrusion to prevent the material from flowing to the flange portion. The protrusion is provided when it does not impede the product nor cause problems of strength and rigidity of the product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for obtaining a part having a boss on a flange by cold forging.

[0002]

2. Description of the Related Art Conventionally, such cold forging has been performed by a method shown in FIGS. That is, as shown in FIG. 2A, a metal core is inserted into a hole of a material, the upper end surface of the boss portion of the material is pressed with a punch, and the flange portion of the material is pressed with a die. In this case, the die is fixed to the upper die. Therefore, as shown in FIG.
Material overlap K occurred at the corner, which was a defect.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for cold forging a part having a boss on a flange, in which no material overlaps at a corner.

[0004]

According to the present invention, a core is inserted into a hole of a material, a resistance is applied to a flange portion of the material, and a punch for pressing an upper end surface of a boss of the material and a die for pressing the flange portion. Are provided so as to be relatively movable in the vertical direction.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, the left half shows a blank 1 and the right half shows a state in which the blank is formed by cold forging.

In the right half of FIG. 1, a lower die fixed to a bolster of a press machine includes a lower die 3, a cored bar 4, and the like. The upper die fixed to the slide of the press machine is composed of a punch 6, an upper die 5, etc., and the punch 6 is urged downward by a punch pin 7 and the upper die 5 by an upper die pin 8, respectively. Have been.

A punch 6 is provided on the outer periphery of the cored bar 4, and an upper die 5 is provided on the outer periphery of the punch 6. Punch 6
And the upper die 5 are relatively movable in the vertical direction.

The upper die 5 is provided with a projection for preventing the material from flowing to the flange. This projection is provided when it does not interfere with the product and does not matter the strength and rigidity of the product.

A core metal 4 shown on the right side of FIG. 1 is inserted into a hole of the material 1 shown on the left side of FIG. When the press machine slide is processed, the punch 6, upper die 5
Is lowered, and the material is subjected to cold forging by the cooperation of the lower die 3, the punch 6 and the upper die 5, and the material 1 becomes the product 2.

FIG. 2 is similar to FIG. That is, the mold structure of FIG. 2 is very similar to the mold structure of FIG. The two points are different from each other in that the upper die 15 has no protrusion and the lower die 13 has a concave portion for restraining the outer peripheral portion of the material.
By the action of the concave portion, the material can be prevented from flowing to the flange portion.

Since the punch 16 and the upper die 15 are separately urged by the punch pin 17 and the upper die pin 18, respectively, they can be relatively moved in the vertical direction. This relationship is the same as the relationship between the punch 6 and the upper die 5 in FIG.

[0012]

According to the present invention, the punch for urging the upper end face of the boss portion of the material and the upper die for urging the flange portion of the material can be relatively moved in the vertical direction, so that the material is applied to the corner of the product. No overlap occurs.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a mold part.

FIG. 2 is a longitudinal sectional view of a mold part according to another embodiment.

FIG. 3 is an explanatory view of processing in a conventional example.

[Explanation of symbols]

1 is a material, 2 is a product, 3 is a lower die, 4 is a core bar, 5 is an upper die, 6 is a punch, 7 is a punch pin, 8 is an upper die pin, 12 is a product, 13 is a lower die, 14 Is a metal core, 15 is an upper die, 16 is a punch, 17 is a punch pin, and 18 is an upper die pin.

Claims (6)

[Claims] 1. A method for obtaining a product having a boss portion on a flange by cold forging, comprising: a punch for biasing an upper end surface of a boss portion of a material; and an upper die for biasing a flange portion of the material.
A lower die facing the upper die, a core bar provided in a lower die, the punch disposed on an outer peripheral portion of the core bar, the upper die disposed on an outer peripheral portion of the punch, The upper die and the upper die have a structure capable of moving relative to each other in the vertical direction, and the core metal is inserted into the hole of the material by using a mold provided with means for preventing the material of the material from flowing to the flange portion. A method for increasing a sheet thickness, wherein a material is formed by the punch and the die to obtain a product. 2. The method according to claim 1, wherein the means for preventing the material from flowing to the flange portion is a projection provided on the upper die. 3. The plate thickness according to claim 1, wherein the means for preventing the material of the material from flowing to the flange portion is a concave portion provided on the lower die for restraining an outer peripheral portion of the material. How to increase. 4. An apparatus for obtaining a product having a boss portion on a flange by cold forging, comprising: a punch for urging the upper end surface of the boss portion of the material; and an upper die for urging the flange portion of the material.
A lower die facing the upper die, a core bar provided in a lower die, the punch disposed on an outer peripheral portion of the core bar, the upper die disposed on an outer peripheral portion of the punch, And an upper die having a structure capable of moving relative to each other in a vertical direction, and a means for preventing material from flowing to the flange portion. 5. The apparatus according to claim 4, wherein the means for preventing the material from flowing to the flange portion is a projection provided on the upper die. 6. The plate thickness according to claim 4, wherein said means for preventing the material of the material from flowing to the flange portion is a concave portion provided on the lower die for restraining an outer peripheral portion of the material. Increase device.