JPH032571B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a punch for forming a groove on a grooved brake disk, mainly used in a disk brake for a two-wheeled motor vehicle.

Conventionally, as shown in FIG. 1, a brake disc of this kind is known in which a long groove b is carved in the radial direction on the sliding surface of the brake disc a to improve drainage performance. Grooving is generally performed using a punch c having a tip with a rectangular cross-section as shown in Fig. In order to bring out the edge of
It becomes necessary to perform the grinding process to the position shown by the dotted line in the figure, which results in an increase in the cutting allowance, resulting in the inconvenience that the machining process is labor-intensive and the material yield is poor.

SUMMARY OF THE INVENTION In order to eliminate such inconveniences, it is an object of the present invention to provide a punch that can suppress the occurrence of sagging at the groove shoulder as much as possible. In a punch for carving a longitudinal groove in the radial direction, the tip surface of the punch body is formed into a chevron shape having a ridge line at the center in the groove width direction, and the tip portion of the punch body is connected to both side edges of the tip surface. Both side surfaces are inclined in a direction to widen the groove width, and one longitudinal end of the tip face located on the radially inner end side of the groove is inclined in a direction to decrease the groove depth. .

Next, the present invention will be explained with reference to embodiments shown in FIG. 3 and below.

In the drawings, 1 indicates a punch body, and the punch body 1
As shown in FIG. 4, the blank holder 6 is slidably inserted into the guide hole 6a of the press die 5, and has a substantially convex cross-section, so that the holder 6 comes into contact with the brake disk a, which is the workpiece. The punch body 1
The distal end of the holder 6 protrudes from the outer surface of the holder 6, and a longitudinal groove b is formed in the radial direction in accordance with the shape of the distal end on the sliding contact surface of the disk a.

The cross-sectional shape of the tip of the punch body 1 is as shown in FIG.
Both side surfaces 3, 3 of the tip part connected to both side edges of the groove b are inclined in the direction of widening the groove width, and as shown in FIG. 3 and FIG. One end 4 in the longitudinal direction of the distal end surface 2 is inclined in the direction of decreasing the groove depth.

Next, to explain its operation, the tip of the punch body 1 is press-fitted into the part sliding surface of the brake disk a, which is the workpiece, while pushing apart the meat with the chevron-shaped tip surface 2, which reduces press-fitting load movement. At this time, the tip side surfaces 3, 3 function effectively to prevent the meat pushed apart by the tip surface 2 from being caught in the press-fitting direction due to their inclinations, and to bring the meat closer to the shoulder of the groove b. The occurrence of sagging in the shoulder area is suppressed as much as possible.

In addition, if the tip surface 2 is formed into a chevron shape having the same height over the one longitudinal end 4 described above, the engraved part and the non-engraved part of the groove b are separated from each other by the radial inner edge of the groove b. This causes a large internal stress difference between the edges 4 and 4, causing distortion due to residual stress after heat treatment.
However, if the end portion 4 is inclined in the direction of decreasing the groove depth as in the present invention, such inconvenience will not occur.

As described above, according to the present invention, the tip surface of the punch body is formed in a chevron shape, and both sides of the tip are inclined in the direction of widening the groove width.
The material gathers around the shoulder of the groove, suppressing the occurrence of sag, making grinding after groove engraving easier, and improving the material yield. By tilting the groove in the direction of decreasing the depth of the groove,
This is designed to reduce the internal stress difference that occurs between the groove on the inner circumference of the brake disc and the non-engraved part, effectively preventing distortion of the brake disc and breakage of the punch, improving productivity and reducing costs. This has the effect of reducing the

[Brief explanation of the drawing]

Fig. 1 is a plan view of a brake disc, Fig. 2 is a cross-sectional view of a conventional punch, Fig. 3 is a plan view of an example of the punch of the present invention, and Fig. 4 is a line taken along the - line in Fig. 3 in its usage state. 5 is an enlarged sectional view of the main part thereof, and FIG. 6 is a sectional view taken along the line -- in FIG. 3. a...Brake disc, b...Groove, 1...Punch body, 2...Tip surface, 3...Tip side surface, 4
...One end in the longitudinal direction.

Claims (1)

[Claims] 1. In a punch that carves a longitudinal groove in the radial direction on the pad sliding surface of a brake disc, the tip surface of the punch body is formed in a chevron shape with a ridge line at the center in the groove width direction, and the edges on both sides of the tip surface Both sides of the tip of the punch body connected to the punch body are inclined in a direction to widen the groove width, and one longitudinal end of the tip face located on the radially inner end side of the groove is made to be inclined in a direction to make the groove depth shallower. A groove engraving punch characterized by being inclined at a slant.