JPH07251235A - Punching forging method - Google Patents

Abstract

PURPOSE: To simplify punching forging steps, to increase production efficiency of products with a vent, and to prevent scraps from generating. CONSTITUTION: Wires 2 are introduced into the circular rear part of die holes equipped with a forming hole part 12 and a preliminary forming hole part 13, while the formed end 21 and the preliminary formed end 22 of the front end of the wire formed in the preceding process, failing to fill the entire space in the forming hole part and the preliminary forming hole part, form the preliminary forming space 14. Blind holes are punched on the end face of the forming end of the wire by a punch 4 and, simultaneously, the preliminary forming space is filled by pressing the wire. With the punch retreating from the blind holes, the wire is driven so that the formed end with the blind holes punched is stored in a storage part 34 provided in a shearing means 3 and thereby fitted into the holding tube 33 inside the storage part. Then, the shearing means 3 is actuated, shearing the formed end stored in the storage means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a punching forging method which does not produce scrap when a product having through holes is processed.

[0002]

2. Description of the Related Art In general punching in manufacturing nuts, transmission chain rollers, and other metal parts of small size and having through holes, punching is performed by punching the central part of the product, so that the punched parts are It is wastefully scrapped, and the number of machine tools for punching is increasing, and the punches and dies are severely worn.

As a means for solving such problems,
No. 3,267,500 U.S. Pat. No. 3,267,500 has been proposed for a punching forging technique which does not produce scrap of a product having a through hole. The contents of the technique are similar to those of the punching forging process shown in FIGS. 3A to 3E. Is an intermediate product of nuts, and takes the following steps;

First step: (FIG. 6) A wire B1 having a circular cross section is pushed into a tip portion of a die hole B2 having a hexagonal cross section having an inscribed circle on the outer circumference of the wire B1. In the cycle, the tip of the wire B1 which has already been made into a hexagonal head portion B11 in cross section is brought into contact with the die hole B2, and the punch B4 is held at a position retracted by an appropriate distance to prepare for the downward stroke of the punch B4. .

Second step: (FIG. 7) The presser seat B3 is slightly lifted, and the punch B4 is immediately inserted.
Plastically deforms the hexagonal head portion B11 at the tip of the wire B1 by the first stroke to form a blind hole B12 in the axial direction of the hexagonal head portion B11, and the material punched through the blind hole B12 is a die hole B2. It is pushed between the peripheral wall and the outer peripheral surface of the punch B4 and filled up, and the outer peripheral portion has a hexagonal cross section.

Third step; (FIG. 8) The punch B4 retracts from the blind hole B12 of the hexagonal head portion B11 at the front end of the wire B1, and at the same time, it is separated from the die hole B2 hole with the pressing seat B3, and the shearing operation is performed. The shearing means B5 for moving begins to move to the front end of the die hole B2.

Fourth step: (FIG. 9) The shearing means B5 moves to the opening of the die B2, the wire rod B1 projects and is actuated, and the hexagonal head portion B1 having the blind hole B12.
1 pushes the forehead into the shearing means B5, leaving a part behind, and the supporting tube B6 provided in the axial hole of the shearing means B5 is timely inserted into the blind hole B12 of the hexagonal head part B11. Insert.

Fifth step: (FIG. 10) The shearing means B5 moves together with its supporting tube B6 to form the blind hole B.
Hexagonal head portion B11 of wire rod B1 punched with 12
The hexagonal head portion B11 thus sheared serves as a nut intermediate product having a through hole.

That is, by repeating the above-mentioned five steps, the product having the through hole can be automatically punched and forged.

The technique of the above-mentioned US Pat. No. 3267500 is certainly a method capable of punching and forging a product having through holes without the generation of scrap, and it is possible to significantly reduce the production cost by reducing the waste of materials. It must be a valuable technology, but there are still some problems in the process of punching and forging that are not ideal;

1. In addition to the lateral movement of the presser seat, the hexagonal head of the wire rod is first contracted slightly inside the die hole, and when punching the blind hole, the peripheral portion of the blind hole is pushed up and eats from the front end of the die. This is to prevent burrs from forming, but this operation increases the push-out operation step, and the presser seat and punch constantly operate alternately with the shearing means, both of which spend a considerable amount of time in the movement path. At the same time, the structure for preventing both from interfering with each other and sharing the power while operating alternately becomes extremely complicated.

2. The die hole wall into which the wire is inserted has a hexagonal cross section as a whole, so the manufacturing cost of the die is high, and there is a gap between the circular cross section wire and the hexagonal cross section die hole, Alternatively, when the punch punches, the instantaneous impact force causes the circular cross-section wire rod at the lower end to rattle, resulting in a restless state.

3. Such agitation also affects the depth of the punched blind hole in the punch, that is, the lifted height of the blank material around the blind hole, and the pre-retained wire described in paragraph 1 above. The step between the end face having the blind hole and the end face of the die is affected.

4. When the presser foot presses the front end of the wire rod to form the hexagon head part by punching stroke, there is a gap between the presser seat and the wire rod because the presser seat and the wire rod have a circular cross section. When the wire rod is plastically deformed by punching operation, the effect of the portion protruding from the circular cross section of the wire holding seat is small and it is relatively difficult to make close contact with the peripheral wall of the die hole. The part is relatively dull and unclear, and the nut size standard is usually measured from the ridge line of the ridge part where the two planes intersect, and a certain degree of tolerance is allowed. , If the corner of the nut can be molded more clearly,
It should be possible to reduce variations in measurement size and improve product yield.

[0015]

In view of the problems in the above-mentioned conventional punching and forging method, the present invention simplifies the punching and forging step and does not generate scrap that can enhance the production effect of products having through holes. It is intended to provide a punching forging method.

[0016]

In order to achieve the above object, the punching forging method of the present invention uses a slightly larger hexagonal cross section because the front end of the punching forging process leaves a small portion formed by the previous forging cycle. Outside the molded end of the wire rod, the other part has a circular cross section whose outer diameter is the diameter inscribed in the hexagonal cross section, and the depth part with the open end is the above hexagonal cross section. A forming hole consisting of matching cavities, and then a preforming hole of the cavity that gradually converges from the hexagonal cross section and changes into a circular cross section of the outer diameter of the wire rod, and a circular shape of the cavity approximately equal to the outer diameter of the wire rod. Inside the die hole consisting of the rear end, the tip surface of the tip of the hexagonal cross section is aligned with the outer edge of the molding hole opening, and a preforming space is formed between the die hole wall and the wire. And the first step to insert A second step of punching a blind hole with a punch on the end surface of the front end of the wire rod, and at the same time, pushing the wire rod to plastically deform and filling the preforming space; the punch having completed punching retracts from the blind hole. Then, in synchronization therewith, the storage portion formed by recessing in the shearing means moves to face the molding hole portion hole opening, and further pushes the wire rod to punch the blind hole and deform the molding end portion. A third step of fitting into the storage part so that the blind tube is fitted into a holding tube protruding from the inner bottom part of the storage part; and a molding step in which the shearing means slides laterally and is accommodated in the storage part. A fourth step of shearing the ends;

Then, a through hole is formed in the shearing means so that the punch can punch against the end of the wire rod in the molding hole portion, and the holding tube is always in a fixed position in the storing portion of the shearing means. The contact sleeve is movably pivoted around the holding tube in the storage portion of the shearing means so that the product accommodated in the storage portion can be extruded by the contact sleeve. It would be even better.

[0018]

According to the present invention having the above-described structure, the wire is introduced into the die hole having the molding hole and the preforming hole, and the end surface of the wire rod is formed into the molding hole opening at the end of the preceding step. Forming a flat surface, forming a molding end portion having an appropriate length from the end face of the wire and a preforming step portion having an appropriate length connected thereto, and forming the molding end portion and the preforming step portion Since the preforming space is formed at the rear of the preforming step portion without filling the entire space of the forming hole portion and the preforming hole portion, punching a blind hole with a punch on the end face of the forming end portion of the front end of the wire rod. ,
The wire rod is pushed to fill the preforming space to form a preforming step, and the periphery of the blind hole is pressed by the peripheral wall of the die hole, so that the forming end is completely formed. , The punch, which has completed punching, retreats from the blind hole, and the storage part formed in the shearing means drives the wire rod to correspond to the molding hole opening, and the molding end punched the blind hole. Part is housed in the storage part, and the holding tube in the storage part is fitted into the blind hole, and the shearing means is further moved to shear the molded end part housed in the storage part. Therefore, a product having through holes can be punched and forged without scrap.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional view of a punching forging die used in the present invention. The die 1 is formed by punching a die 1 having a circular cross section along the axial direction at the center thereof. A molding hole 12 having a cylindrical hexagonal cross section having an appropriate length is provided at one end of one hole of the die, and a pre-molding hole 13 having the same hexagonal cross section and having an appropriate length and having a thin taper shape is connected to the molding hole 12. It is provided that the preforming hole 13 is located just between the forming hole 12 and the circular rear end 11 of the circular cross section of the die hole.

Then, the punching and forging step of the present invention comprises:
The description proceeds with reference to FIGS. 2 to 5, respectively;

First step: (FIG. 2) The wire rod 2 is pushed to be introduced into the hole of the die 1, and the front end of the wire rod 2 is extended into the molding hole portion 12 (the front end of the wire rod 2 is A hexagonal cross-section molding end of a certain length left by the process), the end face of which is flat in conformity with the molding hole 12 hole mouth by the previous process, and
The front end of the wire 2 has a molding end portion 21 whose proper length matches the cylindrical molding hole portion 12 from its end face, and is connected to the molding end portion 21 and has an appropriate length of the preforming hole portion. 13 to form a preforming step portion 22 that matches the forming end portion 2
1 and the preforming step portion 22 do not fill the entire space of the forming hole portion 12 and the preforming hole portion 13 and still form the preforming space 14 behind the preforming step portion 22. At this time, the through hole 31 which is the movement path of the punch 4 formed in the shearing means 3 corresponds to the opening of the molding hole portion 12 and the punch 4 tries to punch toward the molding hole portion 12,
In addition, a contact sleeve 32 that is driven to move back and forth is attached to the other end of the shearing means 3, and a holding tube 33 that is always held in a fixed position is pivotally mounted in the inner space of the corresponding contact sleeve 32, and A storage section 34 is provided around the holding tube 33.
Is formed so that the punched forged product 5 having the through hole sheared in the previous step can be accommodated.

Second step: (FIG. 3) The punch 4 passes through the through hole 31 of the shearing means 3 and punches the end face of the molded end portion 21 at the front end of the wire 2 to form a blind hole 23. The wire rod 2 punched through the hole 23 is pushed to fill the preforming space 14 behind the original preforming step portion 22 shown in FIG. 2, and at the same time, the blind hole 23 is punched by plastic deformation due to punching. The end surface of the formed molding end 21 is slightly moved into the molding die 12, and at this time, the other end of the shearing means 3 also performs an operation of ejecting the product in the storage portion 34 sheared in the previous step from the contact sleeve 32.

Third step: (FIG. 4) The punch 4 which has completed punching exits from the blind hole 23, and at the same time, moves away through the through hole 31 of the shearing means 3,
Then, the shearing means 3 moves, the product of the previous process is projected to itself and returned to a predetermined position, and the contact sleeve 32 corresponding to the storage portion 34 is formed corresponds to the opening of the molding die 1. After that, The wire 2 is driven so that the molding end 21 having the blind hole 23 punched in the front end direction is housed in the storage portion 34, so that the blind hole 23 of the molding end 21 is fitted into the holding tube 33. As a result, the preforming space 14 is formed behind the preforming step 22 of the wire 2.

Fourth step: (FIG. 5) The shearing means 3 moves together with the contact sleeve 32 and the pressing tube 33, shears the molding end 21 housed in the housing 34, and has a through hole. Complete the product.

That is, by repeating the above steps in order, it is possible to automatically punch and forge a product having through holes without scrap.

[0027]

Since the present invention is constituted by each of the above steps, it has the following effects. 1. The die hole of the die used is not one formed entirely with a hexagonal cross section, but a cylindrical molding hole with a hexagonal cross section and a preform with a tapered hexagonal cross section at the rear connecting to the molding hole. Since the hole and the circular rear end of the circular cross section connected to the preformed hole are formed to have the predetermined lengths, respectively, the punch punches the blind hole and at the same time, the next product preliminarily reserves itself. The molding is completed, and the step of the punching forging step of the conventional US Pat. No. 3267500, in which the wire rod end having a circular cross section is first formed into a hexagonal cross section end having a predetermined length by the pressing seat, is performed. The production efficiency can be improved by omitting it. By the way, the general nut intermediate product manufacturing rate reaches nearly 1,000 pieces per minute, and if it is possible to omit the step of forming the hexagonal end portion of the wire rod by the pressing seat, it will be less than one day's work. This will save a lot of work time and significantly improve production efficiency.

2. Corresponding to the fact that this operation step can be omitted, the complexity of the mechanical structure can be reduced, and therefore the mechanical structure can be simplified and the failure rate can be reduced.

3. The molding hole of hexagonal cross section is only a part of the whole die hole, that is, it is easy to manufacture the die, and the other end of the wire rod whose front end is molded into hexagonal cross section is restricted to the circular die cross section. Therefore, even if the wire rod receives the impact of the punch, the wire rod can be kept in a stable state.

4. The preforming hole with a hexagonal tapered section in the die hole preforms the wire rod at the same time as the blind hole punching operation to form the taper preforming step, so that the preforming step can be easily plastically formed. Can be provided with perfect corners, and therefore, if the preforming step becomes a molding end, it can be molded into one having perfect corners.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a punching forging die of a product having through holes used in the present invention.

FIG. 2 is a view showing the first step of punching and forging a product having through holes according to the present invention.

FIG. 3 is a view showing a second step of the punching forging according to the present invention.

FIG. 4 is a view showing a third step of the punching forging according to the present invention.

FIG. 5 is a view showing a fourth step of the punching forging according to the present invention.

FIG. 6 is a view showing the first step of punching and forging a product having through holes in US Pat. No. 3,267,500.

FIG. 7 is a view showing a second step of punching forging according to the US patent.

FIG. 8 is a diagram showing the third step of punching forging according to the US patent.

FIG. 9 is a view showing a fourth step of punching and forging according to the US patent.

FIG. 10 is a view showing the fifth step of punching and forging according to the US patent.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Die 11 ... Circular rear end of die hole 12 ... Molding hole 13 ... Preforming hole 14 ... Preforming space 2 ... Wire rod 21 ... Molding end 22 ... Preforming step 23 ... Blind hole 3 ... Shearing means 31 ... Through hole 32 ... Abutment sleeve 33 ... Pressing tube 34 ... Storage part 4 ... Punch

Claims (4)

[Claims] 1. Except for the fact that the front end is a molding end portion (21) of a slightly larger hexagonal cross section due to the remaining small portion that has been molded in the previous forging cycle, the other portion is A wire rod (2) having a circular cross section whose outer diameter is the diameter inscribed in the rectangular cross section is formed into a molding hole (1) which is a cavity whose depth end with an opening end matches the hexagonal cross section.
2), and then the preforming hole (13) of the cavity that gradually converges from the hexagonal cross section and changes into a circular cross section of the outer diameter of the wire (2), and is substantially equal to the outer diameter of the wire (2). Inside the die (1) hole formed by the circular rear end portion (11) of the cavity, the tip surface of the hexagonal cross-section tip is the molding hole portion (1).
2) Aligning with the outer edge of the opening so as to be flush with each other, and preforming space (1) between the die (1) hole wall and the wire (2).
4) a first step of inserting the wire rod (2) into the molding end portion (21) of the front end of the wire rod (2) and punching a blind hole (23) with a punch (4) at the same time;
The second step of pressing and plastically deforming to fill the preforming space (14); in synchronization with the punch (4) having completed punching retracting from the blind hole (23),
The storage part (34) recessed in the shearing means (3) moves to face the hole opening of the molding hole part (12), and further the wire rod (2) is pushed to move the blind hole (23). The molded end portion (21) that has been punched and deformed is fitted into the storage portion (34), and the blind end (23) is fitted into the holding pipe (33) protruding from the inner bottom portion of the storage portion (34). And a fourth step in which the shearing means (3) slides laterally to shear the molding end (21) housed in the housing (34). Punching forging method. 2. A through hole (31) is formed in the shearing means (3) so that the punch (4) can punch against the end of the wire (2) in the molding hole (12). The punching forging method according to claim 1. 3. The punching forging method according to claim 1, wherein the holding tube (33) is always held at a fixed position in the storage portion (34) of the shearing means (3). 4. An abutment sleeve (3) around the circumference of the holding pipe (33) in the storage portion (34) of the shearing means (3).
2. The punching forging method according to claim 1, wherein the product (2) is rotatably pivotally attached so that the product contained in the storage part (34) can be extruded by the corresponding contact sleeve (32).