JPH07195229A - Broach tool - Google Patents

Abstract

PURPOSE:To prolong the life of a broach tool by providing nicks to the rough cutting edge and/or to the semifinishing edge, and by making the shape of the nick of a circular arc or an ellipse, so that the wear can be stabilized, and the sufficient treatment of chips can be enabled even if the repolishing is repeated. CONSTITUTION:The rough cutting edge 2 and the semifinishing edge 3 in a round broach are provided with circular nicks 5. In this case, the shape of the circular nick is determined so as to have a nick width W of approximately 3 times the nick depth H, and the relieving angle of the cutting edge 2 or 3 is made equal to that of the nick 5, and is provided so as to be relative to the relieving surface. By providing a large number of the nicks 5 on the cutting edge relieving surface 7 in accordance with the outside diameter of the cutting edge and the width of the cutting edge, and also by displacing to each other the installation positions of nicks on the front and rear cutting edges in the axial view of the tool axis, sufficient treatment of chips can be enabled, and also the cutting resistance can be reduced for stabilizing the wear of the cutting edge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broaching tool for forming.

[0002]

2. Description of the Related Art In the conventional broach tools,
A U-shaped or V-shaped nick shape was used for the rough processing blade or the intermediate finishing blade. As an example of the U-shape, Japanese Patent Laid-Open No.
As shown in No. 250916, the corners of the nick are rounded to prevent chipping of the corner of the nick.

[0003]

However, in consideration of the wear of the cutting edge, in the U-shape, since the corners of the nick are convex R, boundary wear occurs due to chipping of the corners. In order to solve the problem, the nick is made V-shaped to make the corners obtuse to stabilize the wear. However, in the V-shaped shape, the nick width in the axial direction tends to gradually decrease due to the influence of the second angle of the cutting edge, so that chip clogging is likely to occur.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a broaching tool which pays attention to a nick shape, stabilizes wear, and can sufficiently process chips even after repeated re-grinding. To aim.

[0005]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a broaching tool with a roughing edge and / or
Alternatively, the intermediate finishing blade is provided with a nick, and the nick shape is an arc or an ellipse. Further, the nick width is set larger than the nick depth of the nick shape. In the nick shape, the second angle of the nick is the same as or larger than the second angle of the cutting edge, and a technical measure is taken to make the shape relative to the second surface of the cutting edge. Here, the shape relative to the second surface of the cutting edge means that, assuming a certain nick, the nick shape in the cross section perpendicular to the tool axis is the same shape over the length of the second surface.

[0006]

By applying the present invention, chipping of the corners of the nick can be prevented and wear of the trailing blade is stabilized. Further, as compared with the V-shaped nick, the nick width does not become significantly smaller in the nick depth direction and the nick width in the tool axis direction does not change, so that chip removability after regrinding can be maintained. Furthermore, by setting the nick width to be larger than the nick depth of the nick shape, chipping of the corner portion of the nick can be further prevented. In the nick shape, the second angle of the nick is the same as or larger than the second angle of the cutting edge, and / or the shape is relative to the second surface of the cutting edge in the nick, thereby further improving The chip disposability after polishing could be maintained.

[0007]

1 to 4 show an embodiment of the present invention, which is a round broach in which rough cutting blades and intermediate finishing blades are provided with arcuate nicks. Here, the arc-shaped nick shape is set to a nick width W that is three times the nick depth H, the second angle of the cutting edge and the second angle of the nick are made equal, and they are provided relatively to the second surface. It is a thing. According to the outer diameter of the cutting blade and the width of the cutting blade, a large number of the above-mentioned nicks, which are the main parts of the present invention, are provided on the second surface of the cutting blade, and the nick installation positions of the front and rear cutting blades in the tool axial direction are mutually By shifting them, sufficient chip disposal was performed, cutting resistance was reduced, wear of the cutting edge was stabilized, and tool life was improved. Table 1 shows the life comparison between the product of the present invention and the conventional product.

[0008]

[Table 1]

S45C which is a carbon steel for machine structure as a work material
The results are obtained by using a material having a cutting length of 50 mm and using a round broach for drilling 30 mm in which the amount of cutting per blade of the broach is 30 μm for the rough processing blade and thereafter gradually reduced by the intermediate finishing blade. Here, as a conventional product, one having a U-shaped nick (hereinafter referred to as conventional product 1) and one having a V-shaped nick (hereinafter referred to as conventional product 2) were used. Compared with the product of the present invention, in the conventional product 1, the nick corner portion was abnormally worn by chipping, and in the conventional product 2, the nick width decreased as the number of times of re-polishing was increased, and the chip disposal could not be sufficiently performed.

[0010]

As described above, by applying the present invention, it is possible to stabilize wear, perform sufficient chip disposal even if the number of times of re-polishing is repeated, and prolong the service life of the broach tool. .

[Brief description of drawings]

FIG. 1 is an overall view of one embodiment of the present invention.

FIG. 2 is an enlarged top view of the roughing blade of FIG.

FIG. 3 is an enlarged view of a cross section perpendicular to the axis of the rough-edged blade of FIG.

4 is a cross-sectional view taken along the line A-A ′ of FIG.

FIG. 5 is an example of a conventional product, and is an enlarged view of a cross section perpendicular to the axis of a roughing blade.

FIG. 6 is another example of the conventional product, and is an enlarged view of a cross section perpendicular to the axis of the roughing blade.

FIG. 7 is an enlarged view of the top view of FIG.

[Explanation of symbols]

 1 Tool Body 2 Roughing Blade 3 Medium Finishing Blade 4 Finishing Blade 5 Nick 6 Cutting Edge Blade Edge 7 Second Face 8 Rake Face 9 Back Face 10 Nick Corner W Nick Width H Nick Depth α Cutting Edge Second Angle φ Nick Second corner of

Claims (4)

[Claims] 1. A broaching tool having a roughing blade and / or a medium finishing blade, wherein the roughing blade and / or the medium finishing blade is nicked, and the nick shape is an arc or an ellipse. Brooch tool to do. 2. The broach tool according to claim 1, wherein a nick width W is larger than a nick depth H of the nick shape. 3. The broaching tool according to claim 1, wherein the second angle φ of the nick is the same as or larger than the second angle α of the cutting edge. 4. The broaching tool according to claim 1, wherein the nick has a shape relative to the second surface of the cutting edge.