KR101580082B1 - Mold unit for producing flat head bolt and the manufacturing method of flat head bolt - Google Patents

Abstract

The present invention relates to a mold unit (1100) for forming a plate head bolt (170), and a method for forming a plate head bolt using the mold unit. The plate head bolt (170) And to provide a technology that can be used in the present invention.
The mold unit 1100 includes a fixing jig 110 for setting the molding material 101, a first mold 120 for primarily molding the plate head of the bolt by punching one end of the molding material set on the fixing jig, And a second metal mold 130 for completing the plate head of the bolt by punching the plate head of the first formed bolt. Particularly, the first mold 120 has a main body 80 having a central bore formed therein, a core 90 fitted to the bore, one end protruding outside the main body, and the other end positioned in the bore A first groove 98 having a circular shape and four inclined surfaces having the same pattern extend to the tip of the first groove to form a second groove 99 in the shape of a quadrangular pyramid .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for forming a flat head bolt,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold unit for molding a plate head bolt and a method for forming a plate head bolt using the mold unit, and more particularly, to a mold structure for improving the quality of a plate head bolt and improving a manufacturing yield .

For example, as disclosed in Korean Patent Laid-Open Publication No. 10-2014-0110701, a process for forming a bolt of a metal material includes the steps of: (a) cutting a metal material to a predetermined length; (b) inserting the cut metal material into a forging mold; (c) pressing the metal material inserted in the forging die to form a hexagonal head on the metal material.

The molding process of the conventional plate head bolt and the mold unit related to the present invention among various types of bolts formed through the above-described process will be described with reference to FIGS. 1 to 8. FIG.

The mold unit 100 for forming the plate head bolt includes a fixing jig 10 for setting a rod-shaped material 1 made of a metal such as stainless steel or aluminum alloy as shown in Fig. 1, A first metal mold (20) for punching one end of the formed material to primarily form the plate head of the bolt; and a punch of the plate head of the primary molded bolt to form a "+" And a second mold 30 for flatly completing the upper surface of the dish head.

The fixing jig 10 is for setting the to-be-molded material 1 which has been cut by a suitable length and then transferred by an arm (not shown), and has a conical recess 11 and a central axis C , And a stopper pin (13) fitted in the setting hole from the opposite side of the conical shaped groove.

1 and 2, the first mold 20 has a U-shaped groove 21 on its one end face, and the second mold 30 has, as can be seen in FIGS. 1 and 3, Quot; + "-shaped protrusions 31 on one end face. The first mold 20 and the second mold 30 are fixed to the mold moving base 50 so as to be selectively movable forward and backward along the direction of the center axis C of the conical recess 11 of the fixing jig 10. [ do. The mold moving base 50 is configured to be positionally movable along the vertical direction perpendicular to the direction of the center axis C of the conical recess 11 of the fixing jig 10.

A process of forming the plate head bolt using the conventional mold unit 100 configured as above will be described with reference to FIGS. 1A and 1D.

First, as shown in FIG. 1A, the material to be molded 1 is transferred between the stationary jig 10 and the first metal mold 20, that is, to the front position of the groove 11 of the stationary jig 10.

The transferred workpiece 1 is pushed into the fixing jig 10 by the first mold 20 and set therein and at the same time the workpiece 1 is punched by the punching action of the first mold 20, A substantially rectangular primary dish head 61 is formed as shown in Figs. That is, when the first mold 20 is punched to the fixing jig 10 at a high speed, the tip of the to-be-molded member 1 is brought into contact with the U-shaped groove 21 of the first mold, The U-shaped groove 21 of the first metal mold strongly impacts the tip end of the workpiece 1 as soon as the other end of the workpiece 1 is caught by the stopper pin 13. In this process, the tip end of the material 1 exposed in the space between the U-shaped groove 21 of the first metal mold and the conical recess 11 of the fixing jig is momentarily pressed and squeezed, The dish head 61 is formed. Of course, the position at which the workpiece 1 is stopped in the setting hole 12 can be adjusted by appropriately controlling the position of the stopper pin 13 of the fixing jig.

1C, the mold moving base 50 is moved to the position where the center axis of the second mold 30 and the center axis of the fixing jig 10 coincide with each other The second mold 30 is punched to the fixing jig 10 at a high speed to punch the center of the first plate head 61 with a "+" shaped protrusion 31 to form a "+" groove The plate head portion 62 of the bolt is completed by pressing to the conical groove 11 of the fixing jig so that the surface of the plate is flat.

1D, the mold moving base 50 is moved to the home position (FIG. 1A) and the stopper pin 13 is moved to the conical shape of the fixing jig The semi-finished bolt 65 having the dish head portion 62 formed thereon is pushed toward the groove 11 and separated from the stationary jig 10.

As described above, the semi-finished bolt 65 having the dish head 62 is completed with the bolts 70 by forming a thread using a separate threading device (not shown).

The dish head bolt 70 to be machined by using the conventional mold unit 100 is formed into a blunt structure having a predetermined thickness t without sharp edges at the edges of the dish head 62 as shown in Fig. The conventional plate head bolt 70 has a gap between the bolt insertion hole 41 and the plate head 62 when the plate head bolt 70 is fastened and fixed to the panel 40 in which the plate head bolt insertion hole 41 is formed as shown in FIG. A problem occurs.

8, when the position of the stopper pin 13 is appropriately adjusted in the forming process of the dish head 62 and the punching pressure of the second metal is increased, The edge of the dish head 62 may be easily split or cracked, and the yield of the normal product may be significantly reduced to 50% or less. The conventional plate head bolt 70 has a disadvantage in that it is inevitably required to form the edge thickness of the plate head portion 62 to be thick.

8, the cause of the defect in the edge of the dish head portion 62 is that the primary dish head portion 61 formed by the U-shaped groove 21 of the first metal mold is formed as shown in FIGS. 4 and 5 The spherical portion is pressed into the shape of the dish head by the second metal mold 30 so that the strong pressure and the impact act in a radial direction from the upper side of the first dish head portion 61 to be relatively thin It is believed to be concentrated at the edges.

Korean Patent Publication No. 10-2014-0110701

It is an object of the present invention to provide a mold structure capable of improving defective plate head forming of a bolt.

Another object of the present invention is to provide a method of forming a dish head bolt with improved quality.

It is still another object of the present invention to provide a mold structure and a method of forming a bolt in which the manufacturing yield is not reduced even when the edge of the plate head portion of the bolt is sharply formed.

10 and 12, a fixing jig 110 for setting the to-be-molded member 101, and a plate jig for fixing the plate head of the bolt by punching one end of the to- And a second metal mold (130) for punching the plate head of the first formed bolt to complete the plate head of the bolt, wherein the first metal mold (120) As a result,

The first mold 120 includes a main body 80 having a central passage formed therein, and a core 90 fitted in the passage so that one end thereof protrudes outside the main body and the other end is positioned within the passage. ,

A first groove 98 having a circular shape and four inclined surfaces having the same pattern extend to the tip of the first groove to form a second groove 99 in the shape of a quadrangular pyramid. do.

The first groove is located at the center of the second groove and is formed deeper than the second groove.

The other end of the core is configured to be elastically supported via the spring (125) in the passage.

The method of forming a plate head bolt of the present invention includes the steps of setting a material to be molded 101 on a fixing jig 110,

A circular first groove 98 formed in the core 90 of the first mold 120 and four inclined surfaces having the same pattern extend to the tip of the first groove 98 to form a second groove 99 ) Region to be in contact with the end portion of the material to be molded (101) to form a primary dish head portion (161)

And punching the center of the primary dish head with a second metal mold having a "+" -shaped projection to finish shaping the dish head 162 of the bolt.

The core of the first mold is resiliently biased by the spring 125 to absorb some impact when the end portion of the molding material 101 is punched.

The present invention is characterized in that when the head of the dish is first molded by punching the workpiece 101 set on the fixing jig 110 with the first mold 120, (98: round) and the second groove (99: four inclined planes of the same pattern extend to the tip of the first groove to form a quadrangular pyramid) are brought into contact with the end portion of the material to be punched, Even if the edge of the head is formed into a sharp angle, the edge portion is not easily broken or broken.

Further, it is possible to obtain an effect of improving the quality of the plate head bolt and drastically improving the production yield.

FIGS. 1A to 1D are sectional views for explaining a conventional plate head bolt forming process. FIG.
Fig. 2 is a three-dimensional view of a concave portion of a conventional first mold; Fig.
Fig. 3 is a three-dimensional solid view of a conventional second mold; Fig.
4 is a three-dimensional view showing a state in which a primary dish head is formed by a conventional first mold;
5 is a cross-sectional view taken along line AA of Fig.
6 is a three-dimensional view of a conventional plate head bolt.
7 is a sectional view showing a state in which a conventional plate head bolt is fastened;
8 is a three-dimensional view illustrating the defective state of the plate head bolt.
9 is a three-dimensional view showing a first mold of the present invention.
10 is an exploded perspective view of Fig.
11A is a sectional view of Fig.
11B is a cross-sectional view showing a state in which the core of the first mold is retracted into the main body.
12A to 12D are sectional views for explaining the forming process of the plate head bolt of the present invention.
13 is a three-dimensional view showing a state in which a first dish head is formed by a first mold according to the present invention;
14 is a cross-sectional view taken along line BB and line CC in Fig. 13;
15 is a three-dimensional view of the dish head bolt of the present invention.
16 is a cross-sectional view showing a state in which a dish head bolt of the present invention is fastened;

A method of forming a plate head bolt using a mold unit for forming a plate head bolt according to the present invention and a method of forming a plate head bolt using the mold unit will be described in detail with reference to FIGS. 9 to 16. FIG.

The mold unit 1100 of the present invention includes a fixing jig 110 for setting a rod-shaped material 101 made of a metal such as stainless steel or aluminum alloy as shown in Fig. 12, A first metal mold 120 for punching one end of the ash to form a plate head portion of the bolt; and a punching plate head of the primary formed bolt to form a "+" And a second mold 130 for flatly completing the sub-surface.

The fixing jig 110 is for setting the to-be-molded material 101 that has been cut by a suitable length and then transferred by an arm (not shown). The fixing jig 110 has a conical recess 111 having an angle of 90 to 92 °, A setting hole 112 extending through the center axis of the groove and a stopper pin 113 fitted in the setting hole from the opposite side of the groove. The fixing position of the stopper pin 113 can be appropriately adjusted according to the length of the material to be formed 101. The second mold 130 has a conical "+" protrusion 131 on one end face.

The first mold 120 and the second mold 130 are fixed to the mold moving base 150 so that they can selectively advance and retreat along the center axis C of the fixing jig 110. [ The mold moving base 150 is configured to be movable in the vertical direction perpendicular to the direction of the central axis of the fixing jig 110.

The fixing jig 110 and the second mold 130 constituting the mold unit 1100 have the same technical structure and operation as those of the fixing jig and the second mold constituting the conventional mold unit, The first mold 120 will be described in detail.

The first mold 120 of the present invention is composed of a main body 80, a core 90, a spring 125, and a fixing pin 121 as shown in Figs. 9 and 10.

A first passage 81 having a small diameter and a second passage 82 having a large diameter are formed in the center of the main body 80 so as to communicate with each other along the central axis. The first passage 81, A step 84 is formed at the boundary between the first and second protrusions 82 and 82. On the inner wall of the second passage 82, a groove 83 is formed in a direction parallel to the center axis direction.

On the other hand, the core 90 is inserted into the first passage 81 and one end thereof is exposed to the outside of the main body so as to be able to flow, and the other end is caught by the step 84 of the second passage 82, A protruding protruding portion 91 is formed. The outer surface of the swollen protrusion 91 is fitted in the groove 83 of the second passage so as to form a guide protrusion 92 for keeping the advancing / retreating direction of the core 90 constant. The distal end of the fixing pin 121 is fitted in the second passage 82 of the main body and the other end is fixed to the main body.

The spring 125 is fitted in the fixing pin 121 and is in contact with the other end of the core 90, that is, the bottom surface of the swelling projection 91. The spring 125 is interposed between the bottom surface of the fixing pin 121 and the bottom surface of the swelling projection 91 to urge the core 90. When the pressure is not applied to the tip of the core 90, The distal end of the core 90 is retracted toward the main body 80 as shown in FIG. 11B. At the position where the tip end of the core 90 slightly protrudes from the end region of the main body 80, the bottom surface of the rising protruding portion 91 is fixed (fixed) so that the core 90 is no longer pushed toward the main body regardless of the pressure applied to the tip of the core And is supported at the tip of the pin 121.

When the core 90 is retracted to a position slightly protruding from the end region of the main body 80 by the constitution of the first mold 120 of the present invention as described above, And the core 90 is no longer pushed toward the main body 80 at that position.

Particularly, a circular first groove 98 and four inclined surfaces 99a, 99b, 99c and 99d of the same pattern are formed in the center of the tip of the core 90 constituting the first metal mold 120 of the present invention, And a second groove 99 extending to the tip of the groove to form a quadrangular pyramid is formed. The circular first groove 98 is located at the center of the second groove 99 and is formed deeper than the second groove. The circular groove 98 is configured to be recessed into a round disc shape.

Next, the forming process of the plate head bolt of the present invention will be described in detail with reference to FIGS. 12A to 12D.

First, as shown in FIG. 12A, the material to be shaped 101 is fed to the front position of the conical groove 111 of the fixing jig 110.

The transferred molding material 101 is pushed toward the fixing jig 110 by the first mold 120 and set on the fixing jig 110 as shown in FIG. 12B, and at the same time, by the punching action of the first mold 120, The primary dish head 161 having the first groove 98 and the second groove 99 coupled with each other is formed at the end of the molding material 101 as shown in Figs.

 The primary dish head 161 includes a disc-shaped protrusion 168 formed corresponding to the first groove 98 of the first mold and a recessed portion 168 corresponding to the four inclined surfaces 99a, 99b, 99c and 99d of the first mold And includes inclined planes 169a, 169b, 169c, and 169d that are formed.

Hereinafter, the punching action of the first mold will be described in more detail. When the first mold 120 is punched and moved at a high speed toward the fixing jig 110, the tip of the molding material 101 is brought into contact with the first groove 98 and the second groove 99 of the first mold, The first groove 98 and the second groove 99 of the first mold are pressed against the molding material 112 as soon as the other end of the molding material 101 is caught by the stopper pin 113 and stopped moving, (101).

At this time, since the impact applied to the tip of the to-be-molded member 101 can be partially alleviated to the position where the elasticity of the spring 125 acts, an excessive impact is instantaneously applied to the tip of the to- It is possible to prevent the bonding force from becoming weak.

In the punching process of the first mold 120, the to-be-molded member 101 (see FIG. 1) exposed in the space between the first groove 98 and the second groove 99 of the first mold and the conical recess 111 of the fixing jig, Is spread in a radial manner while being pressed and pressed, thereby forming the primary dish head 161 having the structures of Figs. 13 and 14.

12C, the mold 120 is retracted and the mold moving base 150 is moved to a position where the center axis of the second mold 130 and the center axis of the fixing jig 110 coincide with each other The second mold 130 is punched to the fixing jig 110 at a high speed and the center of the first plate head 161 is punched with a "+" shaped protrusion 131 to form a "+" The plate head portion 162 of the bolt is completed by pressing the plate to the concave shaped groove 111 of the fixing jig so that the surface is flat.

When the second plate 130 is punched with a disc-shaped protrusion 168 and a first dish head 161 including four inclined planes 169a, 169b, 169c and 169d, the center of the circular protrusion 168 The radial punching pressure is applied along the direction of the arrow shown in Fig. 13 as the tip of the " + "-shaped projection 131 digs, and the flat portion of the second mold 130 is inclined by four inclined planes 169a, 169b, 169c And 169d, the boundary between the four inclined planes 169a, 169b, 169c, and 169d is relatively more protruded as compared with the other portions, so that the punching pressure is increased in the radial direction The pressure acting on the edge of the primary dish head 161 can be evenly dispersed and reduced.

Therefore, even if the dish head portion 162 is formed so that the edge has a sharp angle as shown in Fig. 15, defective edge cracking or cracking of the dish head portion 162 does not occur. When comparing the semi-finished bolts formed with sharp edges of the dish head portion using the mold unit of the present invention and the conventional mold unit, when the conventional mold unit was used, the production yield was 50% or less. However, The yield was 99.8% or more when used.

12D, the mold moving base 150 is moved to the home position (FIG. 12A) and the stopper pin 113 is moved to the conical shape of the fixing jig The semi-finished bolt 165 having the dish head 162 formed thereon is pushed to the groove 111 and separated from the stationary jig 110.

As described above, the semi-finished bolt 165 having the dish head 162 is completed with a bolt 170 by forming a thread using a separate threading device (not shown).

The plate head bolt 170 processed using the mold unit 1100 of the present invention is formed such that the edge angle of the plate head 162 is sharp as shown in FIG. There is an advantage that the gap between the bolt insertion hole 141 and the dish head 162 is not opened and the appearance is good.

The method of forming the mold unit 1100 and the head bolt 170 of the present invention described above is not limited to the concrete examples and drawings for carrying out the present invention and can be variously changed without departing from the technical idea and purpose of the present invention .

1,101 - Formed material
10,110 - Fixing jig
11,111 - Conical shaped groove
12,112 - Setting Hole
13,113 - Stopper pin
20,120 - First mold
21 - U-shaped groove
30,130 - second mold
31,131 - "+" shaped protrusions
40,140 - Panel
41,141 - Plate head bolt insertion hole
50,150 - Mold movement base
61,161 - Primary dish head
62,162 - Plate head
65,165 - semi-finished bolts
70,170 - Plate head bolts
80 - Body
81 - The first barrel study
82 - The second subsection
83 - Home
84 - Steps
90-core
91 - Swelling protrusion
92 - Guide projection
98 - first groove of circular shape
99a, 99b, 99c, 99d - slopes
99 - second groove
100,1100 - Mold Unit
121 - Fixing pin
125 - spring
168 - disc-shaped projection
169a, 169b, 169c, 169d - sloping planes

Claims (5)

A first mold 120 for first forming a plate head of the bolt by punching one end of the material to be set on the fixing jig for setting the material to be molded 101, And a second metal mold (130) for punching the plate head of the bolt to complete the plate head of the bolt, the plate head bolt forming mold unit comprising:
The first mold 120 includes a main body 80 having a central passage formed therein, and a core 90 fitted in the passage so that one end thereof protrudes outside the main body and the other end is positioned within the passage. ,
A first groove 98 is formed in the end face of the core exposed to the outside and a second groove 99 is formed in the shape of a quadrangular pyramid by extending to the tip of the first groove, And the first groove is located at a central portion of the second groove and is formed deeper than the second groove.
delete The method according to claim 1,
And the other end of the core is configured to be sandwiched by the spring (125) in the through-hole.
Setting the material to be molded (101) on the fixing jig (110)
A first groove 98 that is formed to be recessed in a round disc shape on the end face of the core 90 of the first mold 120 and a second groove 98 which is formed by centering the first groove and having four inclined surfaces of the same pattern, Forming a first dish head portion 161 by punching a region of the second groove 99 which is continuous with the front end of the first concave portion and which is recessed from the first groove to form a quadrangular pyramid, ,
And forming the plate head 162 of the bolt by punching the center of the first plate head with the second mold 130 having the "+" -shaped protrusions.
5. The method of claim 4,
Wherein the core of the first mold is configured to be resiliently biased by a spring (125) to absorb an impact upon end punching of the molding material (101).

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