JP4012738B2 - Broaching tool for machining hard materials - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a broaching tool for machining an inner diameter hole of a high-hardness material having an R shape with a small curvature radius in a petal shape.
[0002]
[Prior art]
As a broaching tool for processing a hard material with a hardness equivalent to HRC 35-55, for example, in Japanese Patent Laid-Open No. 7-195228, the cutting edge of the broaching tool is made of powder high speed steel or cemented carbide and coated with a hard coating Japanese Patent Application Laid-Open No. 6-315820 discloses a rough cutting blade having a corrugated cutting edge shape and a corrugating shape with respect to the front blade in the cutting direction. A broaching tool is disclosed in which several intermediate blades are provided between the rough cutting blade and the intermediate finishing blade to smooth the cutting surface of the rough cutting blade. However, there is no disclosure about the inner diameter drilling of a high-hardness material having an R shape with a small radius of curvature in the shape of a petal. An R-shaped cutting blade continuous in the axial direction for cutting the machining allowance along the R-shape was used.
[0003]
In such a conventional broach as shown in FIG. 4, when cutting at a high speed of 10 m / min or more, the chips to be cut with the R-shaped cutting blades tend to be wound toward the center of the R shape, so that the chips are small. It becomes difficult to wind. Especially when machining high-hardness materials, the chips are hard, so they fold into a contracted state with a small degree of freedom, as shown in Fig. 5, resulting in chips that do not flow easily and shorten the life of the broach tool. It was.
[0004]
Furthermore, Corona's “New Revised Precision Handbook”, edited by the Precision Machinery Society, page 354, shows the “progressive cutting method” shown in FIG. 6 as an internal broaching method for round holes in forged and cast holes. Proposed. In this method, the No.1 blade to No.18 blade are broaching methods in which even-numbered blades and odd-numbered blades have different cutting positions, and the blades are arranged so as to cut alternately in the radial direction and in the horizontal direction. . However, this method requires not only a very complicated and time-consuming broach, but also cuts alternately in the radial direction and in the lateral direction. There was a problem similar to that of the broach shown in FIG.
[0005]
[Problems to be solved by the invention]
An object of the present invention is a broaching tool for machining an inner diameter hole of a high-hardness material having a petal-like R-shape with a small radius of curvature, in which chips are not wound toward each other even in high-speed cutting. Is to provide.
[0006]
[Means for solving the problems]
Therefore, the present invention relates to a broaching tool for machining an inner diameter hole of a high hardness material having an R shape with a small curvature radius in a petal shape, wherein the broach tool divides the R shape into a polygon having a corner portion, and the polygon to simultaneously broaching each side of, broach each blade has a simultaneous cutting edge polygons width brooch each blade corresponding to the length of the polygon sides gradually increases, in broaching, the multi The above-mentioned problems of the present invention have been solved by providing a broaching tool for machining a high hardness material, characterized in that chips are cut at the corners of a rectangular simultaneous cutting blade .
[0007]
【The invention's effect】
With such a configuration, in the broaching process, chips are cut at the corners of the polygonal simultaneous cutting blade, so that a high-hardness material with a hardness of HRC 40 or more having an R shape with a small curvature radius in a petal shape. In the inner diameter hole drilling broach tool, easy-to-wind chips corresponding to the cutting blades that process each side without cutting chips toward the center of the R shape even at high speed cutting of 10 m / min or more. Providing a broach tool to be generated and improving the life of the broach tool.
[0008]
Preferably, the polygonal simultaneous cutting edge is the R-shaped cutting edge as a finishing cutting edge, and the cutting allowance of one edge is 10 to 15 μm, so that even in high-speed cutting of 10 m / min or more. Chips are easy to wind and can give a clean finish.
Further, the cutting edge of the broach tool is made of powder high speed steel or cemented carbide, and the life of the broach tool can be further improved by applying a hard coating.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a cross-sectional view of an inner diameter hole of a high hardness material having an R shape with a small curvature radius, which is a petal shape, in which the present invention is used. It is explanatory drawing which shows the broach cutting condition by the broach tool for high-hardness-material processing of the processing location which has one R shape by the embodiment of this invention. This hardness is a heat-treated steel having a hardness of around HRC 60. The broaching tool of the present invention is a broaching tool for machining an inner diameter hole of a high-hardness material having a petal-like small radius of curvature R shape 100,... 110, and the R shape 100,. Is divided into polygons divided by radial lines 70, 71, 72... Having the respective sides 41, 42, 43... 51, 52, 53. ..., 61, 62, 63... Each broach blade (not shown) has a polygonal cutting edge in which the width of each broach blade corresponding to the length of the polygonal side gradually increases, In the broaching process, chips cut at the polygonal corners 45, 55, 65... Are discharged.
[0010]
With such a configuration, in the broaching by the broaching tool for machining a hard material according to the embodiment of the present invention, the chips 80 as shown in FIG. 3 cut at the polygonal corner portions 45, 55, 65. As a result, in a broaching tool for drilling inner diameter holes of high-hardness materials with a hardness of HRC 40 or more having a petal-like R-shape with a small radius of curvature of 100, ... 110, even in high-speed cutting of 10 m / min or more To provide a broach tool that generates easy-to-wind chips corresponding to a cutting blade that processes each side, in which chips do not wind toward the center of the R shape, and improves the life of the broach tool became.
[0011]
Preferably, the polygonal cutting edge of the broaching tool is an R-shaped 100,..., 110 cutting edge as a finishing cutting edge (not shown), and 10 m / min by making a cutting allowance of 10-15 μm. Even in high-speed cutting as described above, chips can be easily wound and a beautiful finish can be obtained.
Further, the cutting edge of the broach tool is made of powder high speed steel or cemented carbide, and the life of the broach tool can be further improved by applying a hard coating.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an example of an inner diameter hole of a high-hardness material having an R shape with a small curvature radius, which is a petal shape, in which the present invention is used;
FIG. 2 is an explanatory view showing a broach cutting state of a machining portion having one R shape of the inner diameter hole of FIG. 1 by a high hardness material machining broach tool according to an embodiment of the present invention.
3 is a perspective view of chips that have been broached by the broach tool of FIG. 2; FIG.
FIG. 4 is an explanatory diagram showing a broach cutting situation with a conventional broach tool.
FIG. 5 is a perspective view of chips broached by a conventional broaching tool.
FIG. 6 is an explanatory diagram showing a round hole inner surface broaching method “progressive cutting method” described in Corona, “New Revised Precision Handbook” edited by Seiki Gakkai, page 354.
[Explanation of symbols]
41, 42, 43 ..., 51, 52, 53 ..., 61, 62, 63 ...
45, 55, 65 ... ・ Corner
100, ... 110 ... R-shaped petal-like radius of curvature

Claims (3)

In a broaching tool for machining an inner diameter hole of a high-hardness material having an R shape with a small radius of curvature like a petal shape, the broaching tool divides the R shape into polygons having corner portions, and simultaneously broaching each side of the polygon Each broaching blade has a polygonal simultaneous cutting edge whose width of each broaching blade gradually increases corresponding to the length of the side of the polygon, and in the broaching, the polygonal simultaneous cutting cutting edge A broaching tool for machining high-hardness materials, characterized in that chips are cut at the corners of The high-hardness material processing broach according to claim 1, wherein the polygonal simultaneous cutting edge is the R-shaped cutting edge as a finishing cutting edge, and the cutting allowance of one blade is 10 to 15 μm. tool. 3. The broaching tool for machining a high hardness material according to claim 1, wherein the cutting blade of the broaching tool is made of powder high speed steel or cemented carbide and is coated with a hard coating.

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