JPS628914Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a forging pin for use in a so-called parts former, a machine that manufactures desired mechanical parts by performing a series of forging operations on a metal material.

To manufacture mechanical parts in a desired shape using a continuous forging machine such as a parts former, the material is subjected to a series of plastic working steps. For example, when forming a deep hole, the hole is gradually formed through several steps, and a drilling pin is used in this hole drilling step.

A problem when performing drilling work using a drilling pin is that as the drilling pin is press-fitted, the air that exists between the pilot hole drilled in the previous process and the drilling pin becomes a problem. is being compressed, so
This compressed air must be dissipated. If an escape route for the compressed air is not provided, there is a risk that the compressed air may crack the mechanical parts themselves and destroy them.

For this reason, in conventional hole-punching pins, a small hole for dissipating air is provided in the center of the pin and extends all the way to the upper end of the pin, thereby allowing air to escape from the upper end of the pin. However, the problem with this conventional hole punching pin is that some of the material may flow into the small hole for air escape during forging, so when the pin is pulled out, the material is torn off and the small hole is opened. The problem is that the air gets stuck inside and blocks the small holes for air escape. If the small hole becomes blocked, there will be no way for compressed air to escape when processing the next part.
As mentioned earlier, cracks may occur in the parts themselves, leading to their destruction.

Therefore, the object of the present invention is to insert a solid inner cylinder into a hollow outer cylinder constituting a hole-punching pin and form an annular air escape passage between the two.
To provide a drilling pin so that a part of the material does not remain in an air escape passage when the drilling pin is pulled out.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 4 show the state when drilling is performed using a parts former. In this hole punching step, the material 10 formed into the shape shown in 1 in the previous step is finally plastically deformed into the shape 10' shown in 4. The material 10 is held between a pair of vertically opposing dies 12 and a punching pin 14 provided on the parts former. The state shown in FIG. 1 and 2 is a state in which the upper and lower drilling pins 14 have just begun to enter the holes 16 formed in the material 10 in the previous step. In this state, the inner diameter of the hole 16 is slightly larger than the outer diameter of the punching pin 14, so the air closed by the hole 16 and the punching pin 14 flows into the gap between the hole 16 and the pin 14. can escape to the outside through. The state shown in FIG.
6. In this state, hole 1
Air remaining in the bottom of the pin 6 and in the gap between the hole 16 and the pin 14 is completely trapped by the shoulder 18 of the pin 14 and has no way out. In the state shown in FIG. 1, the upper and lower pins 14 and the die 12 further move forward from the state shown in FIG. 3, inflating the intermediate portion of the material 10 and plastically deforming it into the shape shown at 10'. In this state, there is no gap between the pin 14 and the material 10'. Therefore, the remaining compressed air attempts to escape by generating cracks 20 in the material 10'.

This would destroy the material, so the pin usually has small holes for air escape.

FIG. 2 is a cross-sectional view of a conventional drilling pin 24 with a small hole 22 for air escape. However, in the case of this conventional drilling pin 24, when the material undergoes plastic deformation, a part of the material tends to flow into the small hole 22, and therefore, after completing the prescribed forging process, the drilling pin 24 When retracting the small hole 22, the material that has flowed into the small hole 22 is often torn off and remains in the hole 22, making it impossible to process the next material.

FIG. 3 shows a drilling pin 50 according to the present invention. This drilling pin 50 is composed of a hollow outer cylinder 54 and a solid inner cylinder 52 inserted into the outer cylinder 54, with an annular shape between the two cylinders to allow air to escape. A passage 56 is formed. Further, a distal end surface 58 of the inner cylinder 52 slightly protrudes from a distal end surface 60 of the outer cylinder 54. By making the distal end surface 58 of the inner cylinder 52 slightly protrude in this way, it is possible to prevent the material from flowing into the annular passage 56 when pressing the material.

Since the drilling pin 50 of the present invention is constructed as described above, it is possible to prevent the material from flowing into the annular passage 56 for air escape when undergoing plastic working, unlike the conventional drilling pin. It is possible to eliminate clogging of the air escape holes, which was a drawback of the above.

[Brief explanation of drawings]

1 to 4 are schematic diagrams in the case of performing forging hole drilling using a parts former. FIG. 2 is a sectional view showing the structure of a conventional drilling pin. FIG. 3 is a sectional view showing the hole punching pin structure of the present invention. 52... Inner cylinder, 54... Outer cylinder, 56... Annular passage for air escape.

Claims (1)

[Scope of utility model registration request] A solid inner cylinder is inserted concentrically into a hollow outer cylinder to form an annular passage for dissipating air between the outer cylinder and the inner cylinder, and the distal end surface of the inner cylinder is connected to the distal end of the outer cylinder. A drilling pin for forging that is characterized by slightly protruding from the surface.