JPS5973139A - Punch for indentation - Google Patents

Abstract

PURPOSE:To provide high durability to a punch for indentation by forming the stem part of the punch into an inverted trapezoidal section, exposing only the tool part of the punch and embedding the stem part of the punch into a holder. CONSTITUTION:A stem part 7 of a punch next to a tool part 6 having a rectangular sectional shape is made into an inverted trapezoidal section having the width increasing from the part 6. The width of the tool face 6a in the part 6 is defined as (a), the height thereof as (d), the max. width in the part 7 as (b) and the height thereof as (c) and are determined as b=2a, c=4d. A punch holder 8 consists of blocks 14 and 15 joined by means of a bolt 13, and covers tightly and fully the part 7, thus exposing only the part 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a punch for use in punching a groove-like recess into a relatively hard metal material.

In the case of a disc brake 1 for an automobile, an example of which is shown in FIG. 1, a large number of curved or bent grooves 2 may be provided in front of friction 1a in order to enhance the braking effect.

The groove 2 usually has a square or rectangular cross section, as shown in the enlarged cross-sectional view of the section marked by the line ■-■ in FIG. 1 in FIG. This is required.

However, the material of the disc brake 1 is often stainless steel, which is relatively difficult to process even among iron-based materials, and there are many technical difficulties involved in precisely forming the many grooves 2 by press working. There is.

Conventionally, a groove 2 has been pressed into the friction front 1a of the disc brake 1 using a pan (PCA) in which the punch tool part 3 and the bamboo shaft part 4 are integrated as shown in FIG.
Since chamfering is hardly allowed for human finishing, and since the angle of the inside corner (I) that is the boundary between the punch tool part 3 and the punch shaft part 4 is approximately 90 degrees, the service life of one punch is limited. However, only 30 to 50 indentations were required, resulting in uneconomical results. A detailed investigation of the wear and tear on the punch in this case reveals that most of it is caused by cracks 5 inward from the inside corner (I), and once cracks 5 occur, the punch becomes unusable. .

As a result of continuing research to solve this problem, the inventor of the present application has developed a punch that has a shaft part that gradually widens from the punching tool, and the punch shaft part that follows the punching tool part is covered by a rigid body. It was found that it was possible to prevent the occurrence of cracks from inside corners.

The present invention is based on the above-mentioned knowledge, and provides a punch for indentation with a significantly increased service life. It has an inverted trapezoidal cross-section or a cross-sectional shape similar to this which becomes wider as it gets farther away from the punch, and the punch shaft is buried in the holder with only the punching tool part exposed.

Next, the present invention will be described in detail with reference to the drawings.

FIG. 4 is a cross-sectional view of a portion of the punch (B) according to the first embodiment of the present invention. In the bumper (B) of this embodiment, the punch shaft portion 7 following the bamboo tool portion 6 having a rectangular cross-sectional shape has an inverted trapezoidal cross section that becomes wider as it moves away from the puncher tool portion 6, and the tool surface 6a of the puncher tool portion 6 The width is (a), the height is (d), and the maximum width of the punch shaft 7 is (
b), height is (C), b=2a, c=4
d.

Note that the punch (B) is formed to a length corresponding to the length of groove 2 (see Figures 1 and 2), but the cross-sectional shape in all parts in the length direction is shown in Figure 4. Shape as shown,
The entire punch shaft portion 7 is buried within the punch holder 8.

In the punch (0) of the second embodiment shown in FIG. 5, the punch tool part 9 is an inverted trapezoid with the width of the tool surface 9a as (a) and the height as (d). The punch CD of the third embodiment shown in FIG. is a concave arc surface (
Although it is different from the above two examples in that it is formed in a straight line, the width (a) and height d) of the tool surface 11a of the puncher tool part 11 and the maximum width (b) and height C) of the tool shaft part 12 are as follows. is the same size as the above two examples.

In the first, second, and third embodiments, the punch shaft portions 7, 10, and 12 are respectively embedded in the bump holder 8, and the punch shaft portions 7 of each of these punches (B), (0), and (D) are buried in the bump holder 8. The specific structure of the punch holder 8 in which the .10.12 is buried is, for example, a split structure whose cross-sectional shape is shown in FIG.

Note that FIG. 7 shows a state in which the punch CB of the first embodiment is assembled to the punch holder 8.

That is, the punch holder 8 consists of blocks 14 and 15 connected by bolts 13, and the punch shaft portion 7 is completely covered by the blocks 14 and 15, leaving only the punch tool portion exposed.

In the punch holder 8 having such a structure, the lower surfaces 14a and 158 of the blocks 14 and 15 are connected to the side surface 6b of the punch tool part 6.
, 6b and 90' form an inside corner (I).

The division of the blocks 14 and 15 of the punch holder 8 is just one example, and as long as it has a rigid structure that exposes only the punch tool and densely covers the punch shaft, its shape is determined according to the press machine and the workpiece. do it.

In the figure, 16 is a brake, and (A) is a disc brake.

The punch of the present invention having the above-mentioned structure did not generate any cracks even when large stress was generated in the punch tool parts 6, 9, and 11, and as a result of experiments, it was able to withstand 1000 to 1500 times of indentation.

Therefore, the punch of the present invention has excellent durability as a punch for indentation processing that concentrates a large pressure force on a minute area, and is particularly suitable for indentation processing that forms a large number of grooves with a rectangular cross section on the friction surface of an automobile brake disc.

[Brief explanation of the drawing]

Fig. 1 is a partially schematic front view of an automobile disc brake as an example of a workpiece to be processed by indentation using the punch of the present invention, Fig. 2 is an enlarged cross-sectional view of the portion lined in Fig. 1, and Fig. 3
The figure is a cross-sectional view showing the conventional punch Y-shaped shape, FIG. 4 is a cross-sectional view showing the cross-sectional shape of the first embodiment of the punch of the present invention, and
The figure is a sectional view showing the cross-sectional shape of the second embodiment, and FIG.
FIG. 7 is a cross-sectional view showing the cross-sectional shape of the punch of the first example assembled to the punch boulder. 1... Disc brake, 1a... Friction surface, 2...
・Groove, 2A...Edge, 3,6. '9.11... Punch tool part, 4, 7, 10, 12... Punch shaft part, 8... Punch holder, 13... Bolt, 14
, 1.5... block, prisoner... conventional punch, (B
)...Punch of the first embodiment, (0)...Punch of the second embodiment, (D)...Punch of the third embodiment. Figure l Figure 4 Figure 5 Figure 0 At left

Claims (1)

[Claims] The punch shaft part following the punching tool part having a square, rectangular, or inverted trapezoidal cross-sectional shape has an inverted trapezoidal cross-section or a cross-sectional shape similar to this, which becomes wider as it gets farther from the punching tool part, and only the punching tool part is exposed. A punch for indentation processing characterized by having a punch shaft part buried in a holder.