JPS6210028Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a brazing type end mill, and in particular improves the structure of the center cutting tip that is implanted from the end face side of the end mill, thereby eliminating the inconveniences caused by brazing.

Conventionally, this type of brazing type end mill has been disclosed, for example, in Japanese Utility Model Publication No. 49-4218. This end mill is provided with a plurality of twisted peripheral cutting tips in the axial direction of the main body, and a central cutting tip on the end surface side. Therefore,
Since the joint between the center cutting edge tip and the peripheral cutting edge tip is formed on the cutting edge ridge on the front side, there is an advantage that cutter marks are not formed on the cut surface on the outer circumferential side.

However, as shown in Figure 5 a, b, and c, this center-edge tip has a so-called irregular shape with rounded or chamfered corners on the non-cutting side, and is thinner. be.
Therefore, when the rake face is mated with a peripheral edge tip that is twisted, the thickness tends to be uneven due to the corrective grinding of the center edge tip, as shown in Figure 6a, and the strength and appearance are affected. It was causing inconvenience.

For this reason, in this type of brazed end mill, it is desired to improve the brazed structure so that the strength of the cutting edge does not deteriorate due to correction grinding of the center cutting tip.

The present invention was developed in view of the above-mentioned points, and by brazing a plurality of twisted peripheral cutting chips in the axial direction of the cylindrical tool body, a front cutting edge is formed on the end surface side. A peripheral cutting edge ridge is formed on the ridge and the outer circumferential side, and one of the peripheral cutting edges is adjacent to a center cutting edge tip forming a front cutting edge on the rotation center side. To provide a brazing type end mill in which a ridge extends from an outer peripheral end to near the center of rotation, and in which the brazing structure of the center blade tip is improved.

Hereinafter, one embodiment of the brazing type end mill of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a cylindrical end mill tool body, and a plurality of twisted peripheral chips 2 are brazed to the outer peripheral side surface of the tool body.

A front cutting edge 3 and an outer cutting edge 4 are formed on each of the outer peripheral cutting tips 2, and one of the outer cutting edges 2 has a center cutting edge 5.
are brazed so that they are parallel on the end face side.

The center cutting tip 5 is made of a substantially round rod-like material, and when its rake surface 6 is ground flat, a continuous surface is formed between it and the rake surface 7 of the peripheral cutting tip 2. It's getting old. In addition, near the center point, the rounded side surface of the center blade tip 5 is used as is, so that
The front cutting edge 8 ends.

In addition, FIGS. 3 and 4 show another modification, in which a central cutting tip 5 made of two small round bar materials is applied, whereas FIGS. This is to which the center blade tip 5 of the material is applied. A chamfered side surface is formed on the rotation center side of the central cutting tip 5, so that the front cutting edge 8 ends.

As explained above, the present invention improves the brazing structure of the center blade tip 5, and therefore has the following effects.

First, the rake face alignment of the center cutting tip with respect to the peripheral cutting tip can be easily corrected. This is because the basic shape of the central cutting tip 5 is a round bar, which can be easily understood from FIGS. 6a and 6b. In other words, Fig. 6a shows the cross-sectional shape of the conventional product with non-uniform thickness, but Fig. 6b
This is because there is no thickness defect in the cross-sectional shape of the product of the present invention.

Second, brazing cracks in the center blade tip 5 are less likely to occur. This is because the brazing surface of the center blade chip 5 is cylindrical on the back side, so the directions of compressive and tensile stress after brazing are dispersed and the residual strain is smaller compared to the flat surface of conventional products.

Thirdly, even after re-grinding, the strength of the round tip of the center cutting edge 5 does not decrease much. This makes it easy to lengthen the round bar material of the center blade tip 5.
Therefore, sufficient strength of the cutting edge can be maintained even after re-grinding. Therefore, the cutting performance does not deteriorate even after re-grinding, and long-term use can be expected.

[Brief explanation of the drawing]

Fig. 1 is a partial front view showing one embodiment of the brazing type end mill of the present invention, Fig. 2 is a bottom view thereof, Fig. 3 is a partial front view showing a modified example, and Fig. 4 is a partial front view showing an embodiment of the brazing type end mill of the present invention. , its bottom view, and FIGS.
Figures a and b are cross-sectional views of the center blade tip and the peripheral blade tip in an adjacent state, where a is the conventional product, b
shows the invented product. 1... Tool body, 2... Peripheral cutting tip, 3, 8
...Front cutting edge ridge, 4...Outer cutting edge ridge, 5...Center cutting tip, 6, 7...Rake face.

Claims (1)

[Claims for Utility Model Registration] A plurality of twisted peripheral cutting tips 2 are brazed in the axial direction of the cylindrical tool body 1, so that a front cutting edge ridge 3, An outer cutting edge 4 is formed on the outer circumferential side, and one of the outer cutting edges 2 is adjacent to a center cutting edge 5 forming a front cutting edge 8 on the rotation center side. In a brazing type end mill in which the front cutting edge ridges 3 and 8 extend from the outer peripheral end to the vicinity of the center of rotation, the center cutting edge tip 5 is a substantially round bar-shaped piece that is implanted from the end face side of the tool body 1. At the same time, the cylindrical side surface is formed as a planar rake face 6, so that a continuous surface is formed with the rake face 7 of the adjacent peripheral cutting chip 2, and the rotation center A brazing type end mill characterized in that the front cutting edge 8 is terminated by a rounded or chamfered side surface.