Drill and method of manufacturing drill

Patent metadata

Field	Value
Publication number	US-9827617-B2
Application number	US-201514713432-A
Country	US
Kind code	B2
Filing date	May 15, 2015
Priority date	May 22, 2014
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

According to one implementation, a drill has at least one cutting edge. A projected shape of a passing area of a ridgeline of the at least one cutting edge when the at least one cutting edge is rotated around a tool axis becomes a line-symmetric and discontinuous line along a parabola, two parabolas, an ellipse or two ellipses. The projected shape is drawn on a projection plane parallel to the tool axis.

First claim

What is claimed is:

1. A drill, comprising:
a shank and a cutting edge, the cutting edge including a fixed end coupled to the shank, a free end opposite to the fixed end, and a surface on which ridgelines are provided,
wherein a projected shape of a passing area of the ridgelines of said cutting edge, when said cutting edge is rotated around a tool axis, becomes a line-symmetric and discontinuous line along a parabola, two parabolas, an ellipse, or two ellipses,
wherein the projected shape is drawn on a projection plane parallel to the tool axis,
wherein the line-symmetric and discontinuous line comprises a first symmetrical half on a first side of the tool axis and a second symmetrical half on a second side of the tool axis, each of the first and second symmetrical halves comprising at least three discontinuous points that discontinuously connect continuous line portions, the continuous line portions being linear line segments or continuous curves, and
wherein the at least three discontinuous points of at least one of the first and second symmetrical halves of the line-symmetric and discontinuous line each reside along a common parabola or ellipse that extends convexly from the fixed end of the cutting edge to a vertex located nearer the free end of the cutting edge.

2. A drill of claim 1 ,
wherein the projected shape becomes a line-symmetric polygonal line connecting linear line segments discontinuously.

3. A drill of claim 2 ,
wherein the projected shape becomes a line-symmetric polygonal line discontinuously connecting at least six linear line segments, positions of both ends of each of the line segments being on the parabola, the two parabolas, the ellipse, or the two ellipses.

4. A drill of claim 2 ,
wherein the projected shape becomes a line-symmetric polygonal line discontinuously connecting at least eight linear line segments each tangent to the parabola, the two parabolas, the ellipse, or the two ellipses.

5. A drill of claim 1 ,
wherein the projected shape becomes a line-symmetric curve connecting continuous curves discontinuously.

6. A drill of claim 1 ,
wherein the at least three discontinuous points along the first symmetrical half of the line-symmetric and discontinuous line and the at least three discontinuous points along the second symmetrical half of the line-symmetric and discontinuous line each reside along a common parabola or ellipse.

7. A drill of claim 6 ,
wherein the tool axis of the drill coincides with a major axis of the common parabola or ellipse.

8. A drill of claim 6 ,
wherein a tip point of the drill resides along the common parabola or ellipse.

9. A drill of claim 1 ,
wherein the at least three discontinuous points along the first symmetrical half of the line-symmetric and discontinuous line reside along a first common parabola or ellipse, and
wherein the at least three discontinuous points along the second symmetrical half of the line-symmetric and discontinuous line reside along a second common parabola or ellipse.

10. A drill of claim 9 ,
wherein the first common parabola or ellipse and the second common parabola or ellipse are line-symmetric with one another.

11. A drill of claim 9 ,
wherein a tip point of the drill resides along both the first common parabola or ellipse and the second common parabola or ellipse.

12. A drill having:
a cutting edge including a surface on which ridgelines are provided; and
at least three different point angles defined by three pairs of ridgelines,
wherein the three pairs of ridgelines consist of ridgelines that have ends on a common parabola.

13. A drill having:
a cutting edge including a surface on which ridgelines are provided; and
at least four different point angles defined by four pairs of ridgelines,
wherein the four pairs of ridgelines consist of ridgelines that are tangent to a common parabola.

14. A method of manufacturing a drill,
the drill comprising a shank and a cutting edge, the cutting edge including a fixed end coupled to the shank, a free end opposite to the fixed end, and a surface on which ridgelines are provided,
the method comprising:
setting a material of the drill; and
forming said cutting edge using the material,
wherein a projected shape of a passing area of the ridgelines of said cutting edge, when said cutting edge is rotated around a tool axis, becomes a line-symmetric and discontinuous line along a parabola, two parabolas, an ellipse, or two ellipses,
wherein the projected shape is drawn on a projection plane parallel to the tool axis,
wherein the line-symmetric and discontinuous line comprises a first symmetrical half on a first side of the tool axis and a second symmetrical half on a second side of the tool axis, each of the first and second symmetrical halves comprising at least three discontinuous points that discontinuously connect continuous line portions, the continuous line portions being linear line segments or continuous curves, and
wherein the at least three discontinuous points of at least one of the first and second symmetrical halves of the line-symmetric and discontinuous line each reside along a common parabola or ellipse that extends convexly from the fixed end of the cutting edge to a vertex located nearer the free end of the cutting edge.

15. A method of manufacturing a drill of claim 14 ,
wherein a powder as the material is set in a mold corresponding to said cutting edge, and
said cutting edge is formed by a sinter of the powder.

16. A method of manufacturing a drill of claim 14 ,
wherein a bar-shaped material is set, and
said cutting edge is formed by cutting or grinding the bar-shaped material.

17. A drill having at least one cutting edge,
wherein a projected shape of a passing area of a ridgeline of said at least one cutting edge, when said at least one cutting edge is rotated around a tool axis, becomes a line-symmetric and discontinuous line along two parabolas or two ellipses,
wherein the projected shape is drawn on a projection plane parallel to the tool axis,
wherein the line-symmetric and discontinuous line comprises a first symmetrical half on a first side of the tool axis and a second symmetrical half on a second side of the tool axis,
wherein at least three points along the first symmetrical half of the line-symmetric and discontinuous line reside along a first common parabola or ellipse,
wherein at least three points along the second symmetrical half of the line-symmetric and discontinuous line reside along a second common parabola or ellipse, and
wherein the tool axis does not coincide with a major axis of either the first common parabola or ellipse or the second common parabola or ellipse.

Assignees

• Fuji Heavy Ind Ltd
• Subaru Corp

Inventors

• Saito Manabu
• Nakahata Tatsuo
• Takahashi Hideharu
• Watanabe Masao
• Nishino Toshio

Classifications

• Y10T408/89

  Tool or Tool with support · CPC title

• B23B2251/205

  Five cutting edges · CPC title

• B23B2226/27

  Composites · CPC title

• B23B51/00 Primary

  Tools for drilling machines · CPC title

• B23B2251/14

  Configuration of the cutting part, i.e. the main cutting edges · CPC title