JPS63235040A - Manufacture of bolt having angular head part - Google Patents

Abstract

PURPOSE:To form in good-shaped angular head with good systems flow without the material loss nor run-out and to improve the tool service life and productivity by swaging in an angular head after forming the head part of a regular sized wire rod in larger diameter with axial line drawing forging and forming it in center recessed shape with circular swaging. CONSTITUTION:The wire rod 1 cut in specific dimensional length is inserted into the axial line drawing die 21 of a 1st stage (b) to form a head part 1b in larger diameter by a punch 11. It is then inserted into the die 22 of 2nd stage (c) to swage the head part 1b in circular shape 1c by a punch 12. The circular swaging head part 1c is swaged in the head part 1d of a hexagonal apex part recess 1e at 3rd stage (d). At 4th stage (e) the head part 1d is subjected to pressing and hammering to form in normal angular head part 1f. The hexagonal head bolt having no run-out of the axial core in forging and having good corner bulging at its hexagonal head part is manufactured in good shape without the material loss due to shear cutting nor short service life of a tool to improve the productivity. The material transfer at each stage is performed by a transfer and chuck.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to a continuous multi-stage home machine for bolts used to fasten objects by screwing together, especially stainless steel bolts with rectangular heads, and other bolts. The present invention relates to a method of forging.

(Prior art and problems) A metal material is sequentially formed using a plurality of dies installed horizontally in a row on the fixed base side of the main body frame and a punch installed on the ram side so as to move forward and backward at the corresponding position. In the method of continuous multi-step forging of so-called square-headed bolts that have a hexagonal or other square head integrally attached to the tip of the shaft, the head is formed into a square shape in the final process. The lower part of the neck of the head is placed in the die-shaped hole and the trimmer bunch is driven in with the head supported, and the outer periphery is driven into a square shape (
Trim it to make it look better. Therefore, in this manufacturing method, the ratio of trimming to the material is high, resulting in large material loss, and trimming causes discontinuities in the flow of tissue over the periphery of the head, causing compositional destruction within the material. This caused a problem in terms of strength, and furthermore, the life of the trimmer punch and die was extremely short due to the strong impact action between the trimmer punch and die, which caused problems in terms of productivity and tool cost.

In addition, when the head is forged into a square shape by preforming, the directionality (angle) in the next step becomes a problem, and even if the solder is slightly crooked, the square head cannot be accurately forged.

(Technical Problem) Therefore, in the present invention, it is possible to form a square head only by heading without performing a trimmer step in the final process, and the directionality is not an issue in the preliminary heading to finishing process of the square head. The technical challenge is to make it unnecessary.

(Technical means for solving the problem) In order to solve the above technical problem, the present invention cuts a material consisting of a continuous metal wire or bar material into a fixed size, and at the same time cuts the cut material into a forging section. In the process of forging a bolt material with a square head at one end of the shaft by forging with punches and dies, the shaft is drawn down leaving the part that will become the head. A first step of forming a cylindrical head; a second step of upsetting the cylindrical head so that it protrudes from the die hole and hitting it with a punch to form a conical head with a flat tip; The third step is to punch the bolt material obtained in step 1 so that it fits into the rectangular die-shaped hole, forming a recess on the top surface of the head, and at the same time pressing the outer periphery of the head into a rectangular shape. and a fourth step of correcting the dents in the end surface of the head while supporting the square head so as to protrude from the die hole.

(effect) The above technical means works as follows.

A bolt material 1 having a constant length is obtained by intermittently feeding a material made of a continuous metal round wire rod to the end of the tile by a feeding device and cutting it with a movable knife that moves across the end. (Fig. 1a, Fig. 2a) This bolt material 1 is fed into a forging section at the same time as cutting, where it first undergoes forging in the first step. In the first step, the bolt material 1 carried just before the die 21 is pushed into the die hole 21a by the punch 11 and struck, whereby the first half of the shaft portion 1a is squeezed and the remaining portion becomes the head portion 1b. (Fig. 1 b, Fig. 2 b) The punch 11 moves back and the die hole 21
When the knock ringer 1 to pin 31 protrude from inside a and push out the bolt material 1 of the first process, it is transferred, grabbed with a chuck, and transported to the second process.

In the second step, the bolt material 1' obtained in the first step is press-fitted with the head 1b protruding from the mold hole 22a of the second die 22 so that the shaft portion 1a is upset. When 1b is struck with the second punch 12, the head 1b is pressed and deformed, leaving the shaft 1a as it is, and becomes a conical head 1C with a flat tip. (Fig. 1 C1 Fig. 2 C) Immediately after the second forging process, the punch 12 retreats, and at the same time, the knockout pin 3
2 protrudes and extrudes bolt material 1'' from inside the second die 22.

In the third step, the square head is formed by heading, so the third die 23 is a die mold consisting of a shaft hole 23a and a square hole 23b on the entrance side, and the corresponding third punch 13 has a square hole 23b. A device having a protruding shaft 13a at its tip that fits in a sealed manner is used, and a device having a small spherical protrusion 13b on the end face of the projecting shaft 13a is used.

When the bolt material 1'' obtained in the second step is upset into the third die 23 by this third punch 13 and pressed and hammered, the shaft portion 1
Although a remains as it is, the head 1C is pressed into a square shape at once to become a square head 1d, and at the same time, a spherical depression 1e is formed at the top of the head 1d. (Fig. 1 d, Fig. 2 d) The indentation 1e on the top surface of the head in this third step makes the meat protrude to the outer periphery more strongly, and since this is done in a closed space, the square shape becomes even sharper. becomes.

In addition, in this third step, when the bolt material 1'' obtained in the second step is upset into the third die 23, the head 1C is still circular, so there is no problem with directionality.

In the fourth step, the bolt material 1 obtained in the third step is
0 is extruded by a knockout pin 33, transferred, and carried by a chuck to just before the fourth die 24, and the head is shaped by the fourth punch 14.

In the fourth step, in order to correct the dent 1e on the top of the rectangular head 1d formed in the third step, the shaft portion 1a of the bolt material 10 is upset in the fourth die 24 so as to support it under the neck.
On the punch side, one in which the bottom 914b of the mold hole 14a is made flat is used. Further, in this case, the punch-shaped hole 14a is formed into a circle whose diameter is the diagonal dimension of the square head 1d.

When the head 1d of the bolt material 10 is pressed and hammered with the fourth punch 14 and the fourth die 24, the outer circumference remains square and only the recess 1e at the top becomes flat, resulting in a regular square head 1f. A finished product 20 is obtained.

(Fig. 1 e, Fig. 2 e) After that, this is pushed out with the knockout pin 34, and the finished product 20 is threaded separately, so that the shaft part 1a has a square head 1f at the tip, and the shaft part 1a A bolt product 30 having 1 g of threads is obtained. (FIG. 2f) (Effects) The present invention has the following unique effects.

■ Since trimming with a trimmer punch is not performed in the final process, there is no material loss and material savings can be achieved.

■ Heading of the square head is done in the final two steps, and by forming a dent on the top surface of the head, the square shape is reliably stretched out in one round of heading, and the continuity of the tissue is not impaired, resulting in high strength. becomes.

■ The lifespan of punches and dies is significantly extended, and productivity and workability can be improved.

(2) In the final two steps, especially in the final step, the directionality of the bolt material does not have to be a problem, so the bolt can be easily forged with a bolt former with high precision.

(Example) Each of the first to fourth dice 21, 22, 23, and 24 is mounted on a fixed base 25 of the main body frame in a die block 26.
27, 28, and 29 so that the distances between the dice are all constant.

Punch 11.12.13.14 corresponding to each die
are attached via a punch case to the front end surface of a ram (not shown) which is provided so as to be able to move forward and backward repeatedly at a constant speed by crank motion, and are activated all at once with each movement of the ram.

The punch 13 in the third step has the protruding shaft 13a cut into the die 23.
It is also possible to make the protruding shaft 13a into a prismatic shape corresponding to the square hole 23b, or to make the protruding shaft 13a into a cylindrical shape whose diameter is the opposite side of the square hole 23b.

The punch 14 in the fourth step is formed into a circular mold hole 14a, but a taper is formed at the entrance end of the periphery in order to smoothly fit into the head 1d. Alternatively, as shown in FIG. 3, a lead angle 14a' may be formed over the entire surface. Since this fourth step is a forging to the extent of correcting the end face of the dent 1e at the top, it does not affect the shaping of the square portion of the periphery.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional plan view of the forging part in which the method of the present invention is carried out, and Fig. 2 (a), (b), (c), (d), (e), and (f) shows the order of manufacturing steps for the bolt according to the present invention. It is a side view, and a part shows a cross section. Fig. 3 is a sectional view showing another embodiment of the forging part in the fourth step, Fig. 4 is a sectional view of the punched hole part in the fourth step, and Fig. 5 is a sectional view of the forging part showing the conventional bolt manufacturing method. FIG. 1... Material 1', 1''10.20... Bolt material 1a... Shaft portion 1b, 1c...
・Head ld, 1f...square head

Claims (3)

[Claims] (1) A material made of continuous metal wire or bar material is cut to a certain size, and at the same time the cut material is sent to the forging section and forged with punches and dies, and the bolt material has a square head at one end of the shaft. The first step is to form a cylindrical head at the tip of the shank by drawing the shank while leaving the part that will become the head, and the second step is to make the cylindrical head protrude from the die hole. The second process involves punching the bolt material into a rectangular die-shaped hole to form a conical head with a flat tip. The third step is to form a dent on the top surface of the part and at the same time forge the outer periphery of the head so as to protrude into a square shape. A method for manufacturing a bolt with a square head, characterized in that a fourth step of correcting the end face is sequentially performed. (2) The square head according to claim 1, wherein the end face correction of the dent in the head in the fourth step is performed by punching a circular hole inscribed in the diagonal dimension. Method of manufacturing bolts. (3) The end face correction of the dent in the head in the fourth step is performed using a punch having a circular hole inscribed in the diagonal dimension and a lead angle at the peripheral edge. 2. Method for manufacturing a bolt with a square head as described in Section 1.