KR102457990B1 - Manufacturing method of bolt with a high reduction in section at tip - Google Patents

Abstract

The present invention relates to a method for manufacturing a bolt, in which a bolt with a high reduction ratio of a tip section can be more precisely and smoothly manufactured by only a forging process. The method for manufacturing a bolt comprises the processes of continuously supplying a round bar (8) and forming a first chamfered portion (130a) on the tip of the round bar (8) so that a first molded body (A) is formed and discharged; forming a nipple and a second chamfered portion (130b) in the rear of the nipple on the tip of the first molded body (A) so that a second molded body (B) is formed and discharged; forming a preliminary tip portion (130c) on the tip of the second molded body (B) and a preliminary head portion (120a) on the rear end of the second molded body (B) so that a third molded body (C) is formed and discharged; and precisely forming a final tip portion (130) with a high section reduction ratio and forming a final head portion (120) on the rear end so that a fourth molded body (D) is formed and discharged.

Description

Manufacturing method of bolts with a high reduction in cross-section at the tip {MANUFACTURING METHOD OF BOLT WITH A HIGH REDUCTION IN SECTION AT TIP}

The present invention relates to a bolt widely used for assembly of parts including automobiles, and more particularly, to a method of manufacturing a bolt having a high reduction in cross-sectional area at the tip with respect to a body part constituting the bolt.

A bolt is used to clamp two objects together, and there are various types of bolts.

Among them, referring to FIG. 1 , there is a so-called bolt having a high cross-sectional reduction ratio, in which the diameter d2 of the front end 130 is considerably smaller than the diameter d1 of the body 110 . Since these bolts have a narrow tip when assembling them, they have good binding properties by tightening them.

However, precision molding for bolts with a high reduction in cross-section at the tip was performed in a separate cutting process. This is because, when forming the tip of the tip with a high reduction in area, there was a limit to the precision shaping of the tip even through step-by-step strong adhesion through the forging method.

In addition, if the diameter of the tip 130 is as small as 1.5 mm, it must be discharged by pushing it with a pin corresponding to the small diameter after molding. Otherwise, the pin for ejection is easily broken due to the small diameter.

For this reason, in the manufacture of bolts with a high rate of reduction in the cross-section of the tip, the tip part was made in a separate cutting process instead of forming through the forging method. In addition, the manufacturing cost is increased.

Domestic Registered Patent No. 30-2056624 “Manufacturing method of screw bolt for automobile”

Therefore, the present invention provides a bolt manufacturing method that excludes a separate cutting process for the distal end when manufacturing a bolt having a high rate of cross-sectional reduction at the distal end with respect to the body constituting the bolt, and allows the distal end of the desired shape to be formed only by the forging method. have.

Another object of the present invention is to provide a bolt manufacturing method that enables precise pushing operation and stable forward and backward movement of a discharge pin (die pin) for moving the molded body to the next process during the step-by-step molding process.

In the present invention for achieving the above object, in manufacturing a bolt having a high rate of reduction in section at the tip,

A round bar (8) obtained by cutting a metal wire with a circular cross section to the required length is continuously supplied,

When the round bar 8 is moved to a regular position between the first die 30-1 and the first punch unit 40-1, the first punch unit 40-1 moves toward the first die 30-1. and the round bar 8 is inserted into the mold groove (hole1) of the first die 30-1 by coupling with each other, and at the same time, the tip of the round bar 8 is inserted by the forced pushing of the first punch part 40-1. The process of forming and discharging into the first molded body (A) by causing the first chamfered portion (130a) to be formed on the

When the first molded body A is moved to a position between the second die 30-2 and the second punch unit 40-2, the second punch unit 40-2 moves to the second die 30-2. ) direction and the first molded body (A) is inserted into the mold groove (hole2) of the second die (30-2) by coupling with each other, and the second punch part (40-2) is forced to push the first The process of forming and discharging into the second molded body (B) by causing the second chamfered portion (130b) to be formed at the tip of the molded body (A);

When the second molded body B is moved to a fixed position between the third die 30-3 and the third punch unit 40-3, the third punch unit 40-3 moves to the third die 30-3. ) direction and the second molded body (B) is inserted into the mold groove (hole3) of the third die (30-3) by coupling with each other, and the second molded body (B) is inserted into the mold groove (hole3) of the third die (30-3) by forced pushing of the third punch (40-3). A process of forming and discharging into a third molded body (C) by forming a preliminary tip part 130c of a somewhat coarse shape at the tip of the molded body (B) and forming a preliminary head part 120a on the rear end; ,

When the third molded body B is moved to a position between the fourth die 30-4 and the fourth punch unit 40-4, the fourth punch unit 40-4 moves to the fourth die 30-4. ) direction and the third molded body (C) is inserted into the mold groove (hole4) of the fourth die (30-4) by coupling with each other, and the tip is reserved by the forced pushing of the fourth punch (40-4) As the tip part 130c is pushed and filled in the tip of the mold groove (hole4) of the fourth die 30-4, the tip part 130 with a high final cross-sectional reduction rate is precisely formed, and the final head part 120 is formed at the rear end part. Through the process of forming and discharging into the fourth molded body (D) by forming the bolt, it is possible to precisely and smoothly manufacture a bolt having a high rate of reduction in the cross-section of the tip part only by the forging process.

The present invention reduces material cost and manufacturing cost by manufacturing only a step-by-step forging process in manufacturing a bolt with a high cross-sectional reduction rate using a metal wire rod in manufacturing a washer-integrated bolt, and precision molding and durability by forging process This has the advantage of being improved.

1 is an exemplary view of a bolt having a high rate of reduction in cross-section at the tip;
2 is a manufacturing process diagram of a bolt according to the present invention;
3 (FIGS. 3a to 3d) is a view showing a step-by-step process of forming a bolt having a high rate of reduction in cross-section at the tip according to the present invention;
4 is a cross-sectional configuration view for explaining the configuration of the fourth die 30-4 in more detail.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIGS. 2 and 3 ( FIGS. 3A to 3D ), the bolt 100 having a high rate of reduction in cross section at the tip according to an embodiment of the present invention is integrally formed by forging a raw material having a circular cross section a plurality of times, , especially for precision forming of the tip, the existing cutting process is excluded and precise forming is possible only through the forging process.

That is, when the raw material is supplied and the round bar 8 cut to the required length is supplied, the first molded body (A) → the second molded body (B) → the third molded body (C) → the fourth molded body (D) by four forging processes ) is subjected to stepwise shaping.

A more detailed description is as follows.

) 상태로 공급한다. 금속의 선재는 철사 롤과 같은 형태로서 연속적으로 공급하게 되며 일정 길이로 절단함에 따라 많은 양의 환봉(8)을 공급할 수 있다. First, a round bar (8,

) is supplied. The metal wire rod is continuously supplied in the same form as a wire roll, and a large amount of the round bar 8 can be supplied as it is cut to a predetermined length.

)로 성형과 및 배출이 되게 한다. The cut round bar 8 is moved to a regular position between the first die 30-1 and the first punch unit 40-1, as shown in FIG. 3A. Then, the first punch unit 40-1 is moved in the direction of the first die 30-1, and the round bar 8 is inserted into the mold hole 1 of the first die 30-1 by coupling with each other. In addition, the first molded body (A,

) to form and discharge.

Here, in addition to the first dice 30-1, the second dice 30-2 to the fourth dice 30-4 to be described later are coupled to a fixture (not shown). In addition to the first punch unit 40-1, the second punch unit 40-2 to the fourth punch unit 40-4, which will be described later, are coupled to a moving body (not shown) and reciprocate back and forth to form a pair. The first die 30 - 1 to the fourth die 30 - 4 are coupled and disconnected.

In addition, die spins 31, 32, 33, and 34 are coupled to the first dice 30-1 to the fourth dice 30-4, respectively, and similarly, the first punch unit 40-1 to the second dice 30-4 The punch pins 41, 42, 43, and 44 are coupled to each of the four punch portions 40-4, so that the molding at each stage is smoothly and precisely formed by coupling with each other.

And the die spins 31, 32, 33, and 34 coupled to the first dice 30-1 to the fourth dice 30-4 are push bars P1, P2, P3, and P4, respectively. ) to push out the molded body (A) (B) (C) (D) completed in each step so that it can be moved to the next molding step or discharged.

Next, as shown in FIG. 3b , when the first molded body A is moved to a regular position between the second die 30-2 and the second punch unit 40-2,

)로의 성형과 및 배출이 된다. The second punch portion 40-2 is moved in the direction of the second die 30-2, and the first molded body A is inserted into the mold hole 2 of the second die 30-2 by coupling with each other. In addition, by forcing the pushing of the second punch portion 40-2 to form a second chamfered portion 130b at the tip of the first molded body A, the second molded body B,

) is formed and discharged.

The second chamfer 130b is a step for smoother molding into the preliminary tip portion 130c formed in the next forging step, and a nipple is formed on the tip portion and is formed in a more curved shape behind the nipple.

The first molded body (A) and the second molded body (B) are both formed for the tip portion, and the punch pin 41 coupled to the first punch part 40-1 is the round bar 8 that has been moved. The first die 30-1 has a configuration in which the tip protrudes so that it can be forcibly pushed deep into the mold groove (hole1). Similarly, the punch pin 42 coupled to the second punch unit 40-2 can also force the first molded body A, which has been moved, to be deeply pushed into the mold groove hole2 by the second die 30-2. It also has a configuration in which the tip protrudes.

Next, as shown in FIG. 3c , when the second molded body B is moved to a regular position between the third die 30-3 and the third punch unit 40-3,

)로의 성형과 및 배출이 이루어진다. The third punch part 40-3 is moved in the direction of the third die 30-3, and the second molded body B is inserted into the mold hole3 of the third die 30-3 by coupling with each other. In addition, by the forced pushing of the third punch portion 40-3, a preliminary tip portion 130c of a round shape is formed at the tip of the second molded body B, and a preliminary head portion 120a is formed at the rear end. The third molded body (C,

) is formed and discharged.

The preliminary tip part 130c is a part for forming the final tip part 130 by forced pushing in the next forging step. As it is deformed, it serves to make precise molding according to the desired shape of the tip 130 .

Referring to FIG. 3C , in the die spin 33 inserted into the third die 30 - 3 , a ventilation groove 33b is formed inside the receiving groove 33a. Here, the reason for forming a separate ventilation groove (33b) in the die spin (33) is as follows. That is, the distal end portion of the second molded body B, which has been moved to the third die 30-3 and the third punch unit 40-3, is the receiving groove 33a by the forced pushing of the third punch unit 40-3. ) is press-fitted to the inside to form the preliminary tip portion 130c. At this time, when the air filled in the mold hole 3 of the third die 30-3 and trapped air does not escape outside, the second molded body B is pushed by the mold. It is compressed in the hole 3 and prevents the smooth molding process. Therefore, the ventilation groove (33b) allows the air trapped in the mold groove (hole3) to smoothly escape to the outside.

A preliminary head portion 120a is formed on the rear end opposite to the front end portion with the formation of the preliminary end portion 130c.

Next, as shown in FIG. 3D , when the third molded body B is moved to the original position between the fourth die 30-4 and the fourth punch unit 40-4,

The fourth punch unit 40-4 is moved in the direction of the fourth die 30-4, and the third molded body C is inserted into the mold hole4 of the fourth die 30-4 by coupling with each other. In addition, by the forced pushing of the fourth punch unit 40-4, the front end preliminary end portion 130c has the inner shape of the mold frame, that is, the mold groove (hole4) of the fourth die 30-4 with a high cross-sectional reduction rate, as described above. The tip portion 130 with a high desired cross-sectional reduction rate is precisely formed as it is pushed and deformed while being filled into the interior of the tip. That is, in the present invention, the diameter of the tip 130 of the fourth molded body D is formed as small as 1.5 mm.

)로의 성형과 및 배출이 이루어진다. 머리부(120)에는 렌치홈(121)도 동시에 형성된다. 머리부(12)의 렌치홈(121)은 수요처의 요구에 따라 십자홈이나 육각의 렌치홈 등으로도 형성할 수 있다. At the same time, the fourth molded body (D,

) is formed and discharged. A wrench groove 121 is also formed in the head 120 at the same time. The wrench groove 121 of the head 12 may be formed as a cross groove or a hexagonal wrench groove according to the demand of the customer.

When the formation of the fourth molded body D is completed as described above, the manufacture of the bolt 100 having a high rate of cross-sectional reduction at the tip is completed, and then the final bolt is manufactured by forming a spiral in the body 110 through a separate process. will end

On the other hand, the present invention provides a precise pushing operation of the die spins 31, 32, 33, and 34 for moving to the next process of the molded body, that is, the first molded body (A) to the fourth molded body (D) during the step-by-step molding process. and stable forward and backward movement.

That is, FIG. 4 is a cross-sectional view of the fourth dice 30 - 4 representatively illustrating the fourth dice 30 - 4 , but the first dice 30 - 1 to the third dice 30 - 3 are also all have the same configuration. Referring to FIG. 4 , the fourth die 30 - 4 includes a die mold M4 and a pin guide G4 .

A mold groove (hole4) is formed in the die mold (M4) and the moved third molded body (C) is inserted, molded into the fourth molded body (D) and then discharged. It is inserted so that it can move freely back and forth in (M4) and the pin guide (G4), and it is positioned between the push bar (P4) and the third molded body (C) which is inserted by forced pushing.

In addition, the die spin 34 is divided into a small diameter portion d1 and a large diameter portion d2, the small diameter portion d1 is inserted into the passage pass1 of the die mold M4, and the large diameter portion d2 is the pin guide G4 ), the precise pushing operation of the die spin 34 for step-by-step molding and smooth discharge after molding, especially when the diameter of the tip 130 is as small as 1.5 mm like the fourth molded body (D). It is pushed and discharged with a pin corresponding to a small diameter so that it can be moved back and forth stably with precise control, and also prevents the breakage of the die pin 34 having a small diameter of the small diameter part d1.

According to the above configuration, as shown in ①, when the third molded body C is pushed into the mold hole 4 of the die mold M4, the die spin 34 is pushed back by the force, and as shown in ②, the fourth molded body ( Forming is completed by D) and then, as shown in ③, as the pusher P4 pushes, the die spin 34 moves forward and discharges the fourth molded body (D).

According to the bolt manufacturing method of the present invention as described above, since the existing cutting process is excluded when forming the front end with a high cross-sectional reduction rate, it is unnecessary to install a separate cutting equipment, and precise forming by the forging process is possible, so material wastage due to cutting is reduced. It is possible to increase the production efficiency, and it is also integrally formed by the forging process and thus has excellent durability.

Although specific embodiments have been described in the above description of the present invention, various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be defined by the claims and equivalents to the claims.

(8)--Round bar
(30-1)--First Dice (30-2)--Second Dice
(30-3)--Third dice (30-4)--Fourth dice
(31)(32)(33)(34)--Die Spin
(d1)--Small diameter part (d2)--Large diameter part
(33a)--receiving groove (33b)--vent pipe
(M1) to (M4)--Die mold (G1) to (G4)--Pin guide
(pass1)(pass2)--Passage (P1)(P2)(P3)(P4)--Push Age
(40-1)--First Punch Part (40-2)--Second Punch Part
(40-3)--Third punch part (40-4)--Fourth die
(41)(42)(43)(44)--Punch pin
(A)--First molded body (B)--Second molded body
(C)--Third molded body (D)--Fourth molded body
(100)--Bolts with high reduction in section at the tip
(110)--Body (120)--Head
(120a)--Spare head (121)--Wrench groove
(130)--tip portion (130a)--first faceted portion
(130b)--Second chamfer (130c)--Preliminary tip

Claims (3)

In the manufacturing method of the bolt,
A round bar (8,

) is supplied continuously,
When the round bar 8 is moved to a regular position between the first die 30-1 and the first punch unit 40-1, the first punch unit 40-1 moves toward the first die 30-1. and the round bar 8 is inserted into the mold groove (hole1) of the first die 30-1 by coupling with each other, and at the same time, the tip of the round bar 8 is inserted by the forced pushing of the first punch part 40-1. By allowing the first chamfered portion 130a to be formed on the first molded body (A,

) and the process of forming and discharging,
When the first molded body A is moved to a position between the second die 30-2 and the second punch unit 40-2, the second punch unit 40-2 moves to the second die 30-2. ) direction and the first molded body (A) is inserted into the mold groove (hole2) of the second die (30-2) by coupling with each other, and the second punch part (40-2) is forced to push the first A second molded body (B,

) in the process of forming and discharging,
When the second molded body B is moved to a fixed position between the third die 30-3 and the third punch unit 40-3, the third punch unit 40-3 moves to the third die 30-3. ) direction and the second molded body (B) is inserted into the mold groove (hole3) of the third die (30-3) by coupling with each other, and the second molded body (B) is inserted into the mold groove (hole3) of the third die (30-3) by forced pushing of the third punch (40-3). The third molded body (C,

) in the process of forming and discharging,
When the third molded body B is moved to a position between the fourth die 30-4 and the fourth punch unit 40-4, the fourth punch unit 40-4 moves to the fourth die 30-4. ) direction and the third molded body (C) is inserted into the mold groove (hole4) of the fourth die (30-4) by coupling with each other, and the tip is reserved by the forced pushing of the fourth punch (40-4) As the distal end 130c is pushed and fully filled into the distal end of the mold hole 4 of the fourth die 30-4 and is pushed and deformed, the distal end 130 having a high desired final cross-sectional reduction rate is precisely formed and the rear end is the final By allowing the head 120 to be formed, the fourth molded body (D,

) A method of manufacturing a bolt with a high rate of reduction in the cross-section of the tip, characterized in that it consists of a process of forming into a furnace and discharging.
According to claim 1,
The die spin 33 coupled into the third die 30-3 has a ventilation groove 33b formed inside the receiving groove 33a, so that the third die 30-3 and the third punch part 40-3 are formed. As for the second molded body (B), which has been moved to the , the tip portion is press-fitted into the receiving groove (33a) by the forced pushing of the third punch portion (40-3), and the third die (30-) is formed when the preliminary tip portion (130c) is formed. 3) A method of manufacturing a bolt having a high rate of reduction in the cross-section of the tip, characterized in that it enables smooth molding into the third molded body (C) by allowing the air filled in the mold groove (hole3) of 3) to smoothly escape to the outside.
According to claim 1,
Each of the first dice 30-1 to the fourth dice 30-4 includes a die mold M1 (M2) (M3) (M4) and pin guides G1 (G2) (G3) (G4). becomes,
Each die spin 31, 32, 33, 34 moves freely back and forth within each die mold (M1) (M2) (M3) (M4) and pin guides (G1) (G2) (G3) (G4). It is inserted so that it can be
Each of the die spins 31, 32, 33, and 34 is divided into a small diameter portion d1 and a large diameter portion d2, and the small diameter portion d1 is a die mold (M1) (M2) (M3) (M4) The large diameter part d2 is inserted into the passage pass1 of the pin guides G1, G2, G3, and G4, and the die spin 31 for step-by-step molding and smooth discharge after molding. (32), (33), (34) to enable precise pushing control and stable forward and backward movement, and to prevent breakage of the die spin (34) with a small diameter of the small diameter part (d1). How to manufacture high bolts.

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