JPS6049825A - Drilling method by forging - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a method for drilling holes by forging.

In the drilling process by forging shown in Fig. 1, when drilling a hole in the material with the upper punch a, the concentricity of the upper punch a with respect to the die C is determined by the flow of the material, uneven lubrication, and the flow of the material. Due to the influence of the inclination of the end face, even if the die C and the upper hole A were concentrically aligned with high accuracy, the product often had uneven thickness.

Conventionally, in order to reduce the uneven thickness of the material b' as much as possible, as shown in Fig. 2, preliminary swaging is performed as a step before the drilling process shown in Fig. 1 to improve the parallelism of both the upper and lower end surfaces of the material b'. In addition, the sealing degree is increased so that the outer periphery is in contact with the inner surface of the tie C over as large an area as possible, and the die C at both ends is
A method is used to reduce the amount of non-contact members and personnel involved.

However, if you try to increase the degree of sealing, the processing force for pre-filling will increase exponentially, and if it adversely affects the press machine or mold, there will be a problem of ℃ 5, and the degree of sealing will not be very high. Therefore, it has not been possible to perform forging holes with high precision using conventional methods.

The present invention takes into consideration the above-mentioned problems, and can reduce the machining force for preliminary swaging in the above-mentioned forging hole-drilling method. The purpose of the present invention is to provide a method for drilling holes by forging that can achieve extremely high precision.

Embodiments of the present invention will be described below based on FIG. 3 and subsequent figures.

Figure 3 shows the preliminary swaging process, in which 1 is the lower punch, 2 is the die, and 3 is the preliminary swaging punch. It has a smaller diameter, for example (Q)2 x 0.8 to 0.85, and has a protrusion 4 on its end surface. The diameter of this protrusion 4 is slightly smaller than the diameter of the hole punch, for example, by about 2 inches.

However, when the material 5 is pre-swaged in the preliminary swaging process using the lever, the material 5 is sealed on the inner surface of the die 2, and at the upper end thereof there is a flat part with a diameter smaller than that of the die 2, and a 6
and a recess 7 in the center with a slightly smaller diameter than the general purpose punch.
is formed.

When the material 5 pre-swathed in this way is drilled with the drilling punch 8 in the drilling process shown in FIG. The cutting punch 8 makes a hole along the preformed four parts 7.

The depth of the recess 7 created by the preliminary swaging is equivalent to the axial length of the tapered part of the cutting punch 8, so that the outer peripheral corner of the tip of the cutting punch 8 is aligned with the opening corner of the recess 7 during drilling. Avoid direct contact.

The present invention is based on the above-mentioned item 5, in which the material 5 is pre-swaged, the material 5 is sealed in the die 2, and then the hole is punched with the general purpose punch 8. This is done using a preliminary swaging punch 3 which has a projection 4 at its tip that is smaller in diameter than the hole diameter of the die 2 and has a slightly smaller diameter than the roughness punch 8. The flat part 6 and the four parts 7 having a slightly smaller diameter than the cutter punch 8 are formed in the center, and then holes are punched along the recessed part 7 with the cutter punch 8. The holes can be drilled in the recess 7 without causing misalignment, and a drilled product with good concentricity can be produced. During the preliminary swaging, a flat portion 6 and a recess 7 having a diameter smaller than the diameter of the die 2 are formed on the upper surface of the material 5, so that the material 5 is sealed to the die 2 over its entire axial length during the preliminary swaging. There is no need to perform this process (it is only necessary to seal the upper side thereof, and therefore, the machining force for pre-swaging can be reduced compared to the conventional case.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the state of drilling by forging, Fig. 2 is a sectional view showing the conventional pre-swaging state, Fig. 3 is a sectional view showing the pre-swaging state in the method of the present invention, and Fig. 4 is the drilling state. It is a sectional view showing a state. 2 is a die, 3 is a preliminary swaging punch, 4 is a protrusion, 5 is a raw material, 6 is a plan view, 7 is a four-part punch, and 8 is a rough punch. Applicant Komatsu Ltd. Representative Patent Attorney Masaaki Yonehara Patent Attorney Tadashi Hamamoto 1 Figure 3 Figure 2 Prisoner, Figure 134

Claims (1)

[Claims] In the forging hole drilling method in which the material 5 is pre-swathed, the material 5 is sealed in the die 2, and then a hole is punched with the helical hole bunch 8, the pre-swaging is performed with a hole diameter smaller than that of the die 2, and A preliminary swaging punch 3 having a protrusion 4 with a slightly smaller diameter than the hole punch 8 at the tip is used, and a flat part 6 with a diameter smaller than the hole diameter of the die 2 is formed on the upper surface of the material before drilling, and a hole punch 8 is placed in the center. A method for drilling holes by forging, characterized in that a recess 7 having a diameter slightly smaller than 8 is formed, and then a hole is punched along this recess 7 with a punch 8 for drilling.