KR20040026184A - Closed-die forging method and dies of crank throw pin part - Google Patents

Abstract

PURPOSE: A closed-die forging method and dies of crank throw pin part are provided to maintain shape of the pin part by forging completion using a pin part shape maintaining die after forging the pin part in an almost circular shape using upper bending forging die and pin part forging die when performing bending forging for manufacturing the crank throw. CONSTITUTION: The method comprises process of bending forging a heated "T" character shaped bloom(2) using upper bending die(3) and lower bending die(4); process of forging the forged bloom into the pin part formed in a shape similar to circular shape using a pin part forging die; and process of finish forging the forged bloom using a pin part shape maintaining die. The dies for die forging pin part of crank throw comprises an upper bending die(3) formed in such a shape that width of both ends of the die is narrower than a central part of the die, and curvature is formed in the central part of the die to preform bending forging; a pin part forging die for forging the pin part of the forged bloom in a shape similar to a circular shape; and a pin part shape maintaining die for maintaining shape of the pin part as it is when bending forging the pin part of a bloom whose pin part is forged in a shape similar to a circular shape by the finishing forging.

Description

Crank throw pin part forging method and forging mold {Closed-die Forging Method and Dies of Crank Throw Pin Part}

The present invention relates to a crank throw pin part forging method and a forging die, and more specifically, to produce a crank throw into a large crankshaft for ship engines by using the upper forging die and the pin forging die during bending forging. The present invention relates to a crank throw pin part forging method and a forging die forging a part close to a circle and maintaining the shape until the forging is completed by using a pin part oil current mold.

In order to manufacture a conventional large engine crank throw, as shown in FIG. 1, the ingot is heated in a heating furnace and manufactured in a blob form by hot forging by using a press, and the T-shaped through the forging operation. Forging to bloom of shape. Bloom, forged as described above, is bent to form a 'U' shape using an upper bending forging die and a lower bending mold, and a circular pin by manual gas cutting and mechanical processing of a product folded in 'U'. Process into shapes In this conventional technology, a defect occurs due to a decrease in thickness at the pin and wing connection, and a lot of time is required for the manual gas cutting operation due to the excess material of the pin, and the operator must work in a harmful environment due to noise and gas. There is difficulty.

In the case of the previously patented "partial forging process and forging mold of large crank throw for ship engines" (published number 97-69184), it is difficult for large free forging operations to rotate the material 90 ° after bending forging. It is difficult to align the upper and lower molds because the upper and lower molds must be used in the. In addition, after the finish forging is completed by forming the pin portion, there is a problem accompanied by the dimensional deformation of the other part in the final forged shape.

The present invention has been made to solve the above problems, the object of which is to prevent the defects caused by the reduction of the blade thickness generated during the bending of the crank throw, forging the shape of the pin portion close to the circle to reduce the material, the post-processing process It is to provide the crank throw pin forging method and forging die that can minimize the work efficiency in a comfortable environment and improve working efficiency.

In the present invention, the width of both ends is narrower than the center and the upper bending mold (3) for forging bending due to the curvature in the center, and the pin forging die (5) for forging the pin part of the forged bloom close to the circular shape, It is composed of a pin-shaped oil-like mold (6) which keeps the forged bloom close to the circular shape during the forging of the fin part until the final forging.

1 is a schematic view of a manufacturing process of a conventional crank throw

Figure 2a is an illustration of the upper bending forging die according to the present invention

Figure 2b is an illustration of a conventional lower bending forging die

Figure 2c is a schematic view of the crank throw forging process according to the present invention

Figure 3 is a schematic view of the crank throw pin forging process according to the present invention

Figure 4 is a schematic view of the crank throw finish forging process according to the present invention

<Description of the symbols for the main parts of the drawings>

(1) Ingot (2) Bloom

(3) Upper Bending Mold (4) Lower Bending Mold

(5) Forging Pins (6) Pin Shapes

(7) crank throw

The present invention for achieving the above object is to narrow the width of both ends of the upper bending mold than the center in the conventional crank throw forging method to reduce the amount of flaring of the material during bending forging to prevent the reduction in wing thickness. In addition, by forging the pin portion close to the circle using the pin forging die, and provides a crank throw pin portion forging method and forging die that maintains the forged pin portion until the forging completion using the pin-shaped oil current mold.

Referring to the configuration and the operation of the embodiment of the present invention in detail with reference to the accompanying drawings as follows.

Figure 1 is a schematic view of the manufacturing process of the conventional crank throw, Figure 2a is an illustration of the upper bending forging die according to the present invention, Figure 2b is an illustration of a conventional lower bending forging die, Figure 2c is a crank throw according to the present invention Schematic diagram of the bending forging process, Figure 3 is a schematic diagram of the crank throw pin forging process according to the present invention, Figure 4 is a schematic diagram of the crank throw finish forging process according to the present invention,

The ingot 1 is forged into a T-shaped bloom shown in FIG. The bloom is bent and forged as shown in FIG. 2C by using the upper bending mold 3 of FIG. 2A and the lower bending mold 4 of FIG. 2B. The bloom is forged using the pin forging mold 5 and the lower bending mold 4 of FIG. 2B as shown in FIG. As shown in FIG. 4, the bloom is subjected to a finishing forging process using a flat enville and a pin-shaped oil-type mold 6 as shown in FIG.

As described above, in the present invention, the ingot 1 is heated and then hot forged by a press to be forged into a bloom shape, and the forged T-shaped is heated after the bloom 2 is heated. 3) and bending forging by using the lower bending mold (4), forging the pin part closer to the circular shape using the pin forging mold (5) and the lower bending mold (4), and the pin-shaped oil current mold (6) Finishing with a flat anneal to complete the crank throw (7) in which the pin portion is maintained in shape during bending forging.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

The width of both ends of the upper bending mold is narrower than the center to reduce the gap during bending forging of the bloom to prevent defects due to the reduction of wing thickness, and to replace the upper bending mold with the pin forging mold without moving the position of the bent forged bloom. The use of pin forging die in the same direction as the direction of bending forging enables the forging of the pin part closer to the circular shape, thus improving workability, and using only one mold for forging pins so that two molds of the prior patent (Publication No. 97-69184) The workability is improved without the problem of alignment of the upper and lower molds due to the use, and it is possible to minimize the post-processing by maintaining the shape of the pin part forged close to the circle during bending forging by using the pin-shaped oil current mold. This is a useful invention that can save time and materials, reduce the noise and gas generated during the post-processing to improve the work efficiency by allowing the operator to work in a comfortable environment.

Claims (2)

Bending the forged T-shaped heated bloom (2) into the upper bending mold (3) and the lower bending mold (4); and forging the forged fin to the circular part by means of the forging die (5). Crank throw pin part forging method, characterized in that the process includes the step of finishing forging the forged bloom using a pin part oil-type mold (6). The upper bending mold 3 for narrowing the width of both ends than the center and having a curvature in the center, and the forging die 5 for forging the pin part of the forged bloom close to the circle, and the pin part close to the circle. Crank throw pin part forging die, characterized in that it comprises a pin part oil-like mold (6) for maintaining the forged bloom in the form of bending forging until finishing forging