JPS61137639A - Production of forging - Google Patents

Abstract

PURPOSE:To prevent the burring as a result of piercing and to improve productivity by providing a hole on the coaxial center in the blanking direction of a piercing part and chamfering the hole then stamping a rough shape material to have the hole of which the circumferential part rises perpendicularly to the piercing part and of which the end has an angle part end executing piercing. CONSTITUTION:The rough shape material 1 is formed with the piercing part 2 and the hole 4 having the chamfered part 3 on the coaxial center in the blanking direction of the piercing part in the stage of stamping. The hole 4 is so formed that the circumferential part thereof rises perpendicularly to the part 2 and the top end thereof is a wall having the corner part 5. The material 1 is then fixed onto a die D2 and the part 2 is pierced by a punch D3. The burring is thus prevented and the need for removing the burr is eliminated. The chamfered part 3 has a forging surface and is usable as a product.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for manufacturing a forged product that requires drilling.

(Prior Art) Conventionally, there is a forged product that is formed by forming a rough shape material by stamping and punching holes in the rough shape material.

What is indicated by the reference numeral 51 in FIG. 5 is the above-mentioned rough shape material,
This rough profile 51 has a punched portion 52 and a chamfered portion 53 coaxially connected with the punched portion 52 on the lower end wall, which are formed during stamping. This rough-shaped material 51 is punched at a portion 52 to be punched, and in FIG.
1 with a hole punched therein, 54 is a sheared surface portion thereof, and 55 is a fractured surface portion thereof. The illustrated example is a hot forged product.

(Problems to be Solved by the Invention) However, as shown in an enlarged view in FIG. 7, a burr 56 is generated on the fractured surface portion 55, so a step of removing the burr is required. Furthermore, if the degree of the collar 56 is as severe as in the illustrated example, the chamfered portion 53 will be destroyed and will have to be reprocessed.
When machining is performed using the lower end surface as a reference surface, f))i
IJ 56 is getting in the way and is causing a problem.

Therefore, the present invention solves these problems and f)
The technical objective was to prevent the occurrence of s, j, and 56.

(Means for Solving the Problem) In order to solve this technical problem, the present invention provides a method for manufacturing a forged product having a through hole with a chamfered opening, in the punching direction of the y region to be punched, and A hole located on the coaxial center of the part is provided, this is chamfered, and the peripheral part of the hole is shaped so that it rises perpendicularly to the part to be punched and becomes a wall surface with a corner at the end. It is characterized by punching and then punching a hole by a conventional method.

(Function of the Invention) According to the present invention having such a configuration, stress is concentrated at the corner portion during punching, and a crack forming a fracture surface portion grows toward the corner portion, and as a result, The fractured surface portion is connected to the wall surface, and burrs do not occur as in the conventional case.

(Example) Hereinafter, an example in which the present invention is applied to hot forging will be described with reference to the drawings.

In FIG. 1, l is a rough section formed by stamping, and during stamping, this rough section 1 has a part to be punched 2 and a part to be punched in the punching direction of the part to be punched 2. A hole 4 is formed coaxially with a chamfered portion 3. The hole 4 has its periphery as the punched part 2
It is formed to form a wall surface that rises perpendicularly to the wall surface and has a corner portion 5 at its upper end.

Corner part 5 located at the lower edge of the part 2 to be punched (
(see Fig. 82) is formed sharply so as to avoid curves as much as possible.

The rough profile 1 is fixed on the guide D2 by a presser Dl,
The punched portion 2 is punched in the direction of the arrow by a punch D3. In FIG. 3, reference numeral 1' indicates a hole-punched piece of the rough profile l, 6 is a sheared surface portion thereof, and 7 is a fractured surface portion thereof. Here, as shown in an enlarged view in FIG. 4, a burr 55 as shown in FIGS. It extends in a straight line from the upper end where the crack occurs to the lower end.

The reason why burrs do not occur in this manner is that the stress during punching is concentrated on the corner portion 5, so that the crack grows toward the corner portion 5 and joins therewith.

Therefore, the single chamfered portion 3 will not be destroyed either.

Although the embodiment in which the present invention is applied to hot forging has been described above, the present invention can also be applied to cold forging.

(Effects of the Invention) As is clear from the above description, the present invention has the effect of preventing the occurrence of burrs due to hole punching. This eliminates the need for the 1xt4J removal process, and allows the chamfered portion described above to be used as a product in a forged style.

Furthermore, when grinding or the like is performed on a hole formed by punching, the lower end surface can be used as a reference surface, which has the advantage that the machining can be performed accurately and easily.

Overall, the present invention leads to improved productivity and reduced costs.

[Brief explanation of drawings]

Figure 1~! Figure 4 is for explaining one embodiment of the present invention. Figure 1 is a cross-sectional view of a rough section formed by stamping, Figure 2 is an enlarged view of section B in Figure 1, and Figure 3 is a cross-sectional view of a rough section formed by stamping. The figure is a cross-sectional view of the rough-shaped material shown in Figures 1 and 2 with holes punched, w
Figure IJ4 is an enlarged view of part 0 in Figure 2, Figures 5 to 7 are for explaining the conventional technology and its defects, and Figure 5 is a cross section of a rough section formed by stamping. 6 is a cross-sectional view of the rough profile shown in FIG. 5 with holes punched therein, and FIG. 7 is an enlarged view of section A in FIG. 6. It is. l...Rough profile, 2...Drilled part, 3...Chamfered part. 4... Hole, 5... Corner part 6... Sheared surface part, 7... Fractured surface part

Claims (1)

[Claims] (1) When manufacturing a forged product that has a through hole with a chamfered opening, a hole is created that is located in the punching direction of the part to be punched and on the same axis of the part, which is chamfered, and then A forged product, characterized in that the peripheral part of the hole is stamped so that it rises perpendicularly to the part to be punched and forms a wall surface with corners at the ends, and then the hole is punched by a conventional method. Production method.