JPS59147735A - Die for cold forging - Google Patents

Abstract

PURPOSE:To obtain a titled die that prevents damage of the first forming member and positions both members easily and surely by dividing the first forming member raidally into plural sections and forming a swelled circular arc face on the side of contact between the end of divided section and the second forming member. CONSTITUTION:When forging a nut, the projected tip of a knock out pin K is placed in the forming hole 14 of the first forming member 13. Roughly forged nut material M is put in the hole 14. Under this condition, the material M is pressed by an extruding pin 22 from above the body in the direction of formed convcavity 18. Consequently, external shape of the nut is formed accroding to internal shape of the concavity 18 and hole 14. The distance between inner bottom faces of the concavity Ma of the material M is narrowed by a pin K and projection of the pin 22. As the member 13 is divded before-hand, even if large pressure is applied to inner face of the hole 14 at the time of forging the nut, damage of the member 13 from the corner part of the hole 14 can be prevented before it occurs. Further, as the circular arc face 15 of each divided section 13a is fitted to the concavity 19 of the second forming member 16, positional deviation between the section 13a and formed concavity 18 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a die for cold forging bolts, nuts, etc.

Prior Art Conventionally, in this type of nut forming die, the first,
As shown in Figure 2, the main body 1 (the fitted molded member 2
A nut molding hole 3 having a hexagonal cross section and a knockout bottle insertion hole 4 communicating with the molding hole 3 are formed in the center of the nut. And the roughly pressed nut material M shown in FIG.
In other words, it has an approximately hexagonal column shape, with a recess M in the center.
By press-fitting a material having a into the molding hole 3, 7
A nut is forged according to the inner surface shape of the molded hole 3, and is shaped so that it is pushed out of the main body 1 by a knockout bottle that moves up and down within the insertion hole 4.

However, this conventional structure has a drawback in that due to the large pressure applied to the inner surface of the molded hole 3 during nut forging, cracks occur from the corners of the molded hole 3 (as shown in FIG. 2), resulting in frequent breakage. Furthermore, when forming the molding hole 3, after performing electrical discharge machining, it is necessary to perform a polishing finish that requires skill in order to improve dimensional accuracy.
The drawback is that the work is one-on-one and the cost is high.

In addition, in order to eliminate the above-mentioned defects, a patent application filed on May 25, 1982 (-41) by the same applicant as this applicant,
-88537 specification and drawings (as described here), it has been proposed that the molded member 2 is divided into six parts along a plane including the central axis of the nut molding hole 3 and the knockout bottle insertion hole 4. (See Figure 3).However,
In this conventional configuration, when the nut is forged, due to the pressure applied to the four molding parts 5 (bottom of the molding hole 3), the cracks occur in the middle part of each divided piece (1) and break, as shown in FIG. It turned out to be easy.

Purpose This invention was made in view of the above circumstances,
The purpose is to prevent damage to the first molded member having a molded hole, and to easily and reliably position the first molded member to be removed and the second molded member having a molded recess. To provide a die for cold forging which can be easily assembled and manufactured at low cost.

FIRST EMBODIMENT Hereinafter, a first embodiment embodying this invention will be shown in FIGS. 4 to 7.
A housing hole 11 is formed in the center of the cylindrical main body 10 (through the top and bottom). In other words, the upper half 11a has an oblique shape and the upper half 11a (
It consists of a continuous large-diameter lower half 11b. A tubular member 12 is inserted into the upper half part 11b, and a part of its inner periphery 1a is obliquely shaped like the half part 11a of the housing hole 11. A first molding part 13 made of tool steel such as cemented carbide is inserted into the upper nine parts of the mold.
A molded hole 14 having a hexagonal cross section is formed in the center.

The molding section 13 consists of six divided pieces 13a radially divided along a plane that includes the axis of the molding hole 14 and passes through the inner corner of the molding hole 14.

Further, as shown in FIG. 4.5.7, the lower surface of each divided piece 13a is a circular arc surface 1 that bulges and curves along each inner side of the molding hole 14.
It is 5. Each arcuate surface 15 is formed such that its bulge ratio increases dramatically toward the outer peripheral edge of the first molded member 13.

In other words, the arcuate surface 15 has substantially the same shape as the outer peripheral surface of a truncated cone.

As shown in FIGS. 4 and 5, a substantially cylindrical first molded member 16 made of tool steel such as cemented carbide is fitted into the tubular member 12 below the first molded member 13, and in the center thereof A knockout bottle insertion hole 17 is formed on the extension line of the axis of the molding hole 14 and communicates with the molding hole 14. Also, as shown in FIG. On the two sides of the molded member 16, the opening periphery of the insertion hole 17 is formed. (This is a recess that extends radially Q with the insertion hole 17 as the center, corresponds to the arcuate surface 15 of each divided piece 13a in an uneven relationship, and determines the relative position of each divided piece 13a and each of the four molded parts 18.) A location 19 is formed.

As shown in FIGS. 4 and 5 (the lower half 1 of the accommodation hole 11
A support member 20 is press-fitted and fixed to 1b, and an insertion hole 21 for a knockout hinge is formed in the center thereof and communicates with the insertion hole 10 of the second molded member 16.

Therefore, when forging a nut using a die configured as described in 1. (this is the case, as shown in FIG. With the nut material M that has been rearranged and roughly pressed into the molding hole 14 placed in the molding hole 14, the nut material M is pressed 1" from above the main body 1 toward the four molding parts 18 by the suppression bottle 22. For example, the outer shape of the nut is formed according to the inner surface shape of the molded four parts 18 and the molded hole 14, and the protruding parts of the knockout bottle K and the pressing bottle 22 (thus, the distance between the inner bottom surfaces of the recess Ma of the nut material M is narrowed). It will be done.

The recess Ma is provided to facilitate the formation of a tapped hole after the nut is forged. Thereafter, the knockout bin K is moved and the nut is pushed out to one side.

In this embodiment, even if a large pressure is applied to the inner surface of the molding hole 14 during nut forging, the first molded member 1
3 is divided in advance, it is possible to prevent the first molding member 13 from being damaged even at the corners of the molding hole 14. Furthermore, since the arc surface 15 of each divided piece 13a is fitted into the recess 19* of the second molded member 16, each divided piece 13a does not move erratically even when the pressure is applied, and each divided piece 13a In addition, if the first and second molding members 13 and 16 are worn out or damaged due to the pressure applied to the four molding parts 18, By removing the support member 20, the definition molding members 13, 16 can be easily replaced.

In addition, in this embodiment O, the molded member 13°16
is divided into two parts, and the first molded member 1 is
3 is made up of divided pieces 13a, the periphery of the molding surface is open, and unlike the conventional example, the electrical discharge machining and polishing work for forming the molding hole 14 is easy.
It can be manufactured at low cost.

Now, when assembling this die, as shown in FIG.
Insert 2. Next, each divided piece 13a is attached to the tubular part 4'J.
'12
If the second molded part 16 is fitted into the tubular part 12 with the recesses 19 of the first molded member 16 facing each other, the respective arcuate surfaces 15 (recesses 19 are fitted, and the molded recess 18 of the second molded member 16 can be easily and reliably placed in the predetermined position jl& for each divided piece 13a. Lower half 11b (If you insert this, you will finish assembling the die.)
1- I can do something.

Second Embodiment Next, a second embodiment embodying the present invention will be described with reference to FIG. 8. In this embodiment, the first support member 23 is removably inserted into #Lz for housing the main body 1, and the first support member 23 has an inverted truncated conical support hole 24 and a knockout hole communicating with the support hole 24. A bottle insertion hole 25 is formed. A second molded part 16 having an inverted truncated cone shape is fitted into the support hole 24. Further, a second support portion 4A26 is fitted onto the lower outer periphery of the first support member 23, and the inner periphery 1111 of the accommodation hole 11 is fitted onto the outer periphery of the second support member 26.
A male threaded portion 28 is formed to be screwed into the female threaded portion 27 of.

Therefore, in this embodiment, when replacing the worn second molding member 16 or the first molding member 13 due to continuous molding of nuts, the second support member 26 is rotated in a predetermined direction and the first molded member 13 is replaced. If the support member 23 is removed, the second molded member 16 can be easily removed from the first support member 23 because the second molded member 16 has an inverted truncated cone shape. Furthermore, the first molded member 13 can be easily replaced.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it is also possible to change the shape of the molding hole 14 to, for example, a star-shaped cross section or a petal-shaped cross section as shown in FIG.

Effects As detailed above, the present invention can prevent damage to the first molded member having the molding hole, and also improve the positioning of the first molded member and the second molded member having the four molded parts. can be carried out easily and reliably, and has the excellent effect of being easy to assemble and manufacturing at low cost.

[Brief explanation of the drawing]

1 and 2 show a first conventional example of the present invention, in which FIG. 1 is a sectional view and FIG. 2 is a perspective view of a molded member. FIG. 3 shows a second conventional example, and is a perspective view of a molded member. 4 to 7 show a first embodiment embodying this invention, and FIG. 4 shows the positive 1ii
1i side view, FIG. 5 is a front sectional view during nut molding, FIG. 6 is a plan view, and FIG. 7 is an exploded perspective view of the molding member. FIG. 8 shows a second embodiment of the present invention, and is a front sectional view. FIG. 9 is a plan view showing a modification. Main body 10, accommodation hole 11, first molded member 13, molded hole 14
, arc surface 15, second molded member 16, knockout bottle insertion hole 17, molded recess 1B, recess 19, ridgeline 19a0 Patent applicant: Masu Ogawa, agent
Patent Attorney Hironobu Onda Figure 8

Claims (1)

[Claims] 1. A first molding member (13) having a molding hole (14) for molding a bolt head or nut, and communicating with the molding hole (14) on an extension of the axis of the molding hole (13). A second molded member (1) equipped with a knockout bottle insertion hole (17)
16) and a cold forging die fitted into the accommodation hole (11) of the main forging (10) in an overlapping manner (here, the first molded member (13) is placed in a plane including the axis of the molding hole (14) (Multiple pieces divided radially along this line (1
3a) + trowel, each divided piece (13a) has an arcuate surface (15) bulging out toward the second molding member (16) at the end facing the second molding member (16). and a second molded member (16).
A recess (19) corresponding to the arcuate surface (15) with an uneven relationship is formed, and an edge i#(1) between each recess (19) is formed.
9a) is a cold forging die characterized by extending radially.