Drill

Patent metadata

Field	Value
Publication number	US-9352399-B2
Application number	US-201214009403-A
Country	US
Kind code	B2
Filing date	Apr 11, 2012
Priority date	Apr 15, 2011
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

A drill comprises a drill body that is rotatable on an axis. Chip evacuating flutes, which are open on front flanks of the drill body and are extended rearwards, are formed in a periphery of the drill body on its front side. Cutting edges are formed along ridge lines where the front flanks intersect with wall surfaces of the chip evacuating flutes facing a drill rotating direction. At least first and second front flanks are formed on the front flanks in order of their locations in the drill rotating direction from its leading side to its trailing side. A clearance angle of the second front flank is greater than that of the first front flank. Intersection lines of the first and second front flanks cross the cutting edges.

First claim

The invention claimed is:

1. A drill comprising:
a drill body rotatable on an axis containing;
front flanks, each in the form of a single inclined plane,
chip evacuating flutes, which are open on said front flanks of the drill body and are extended rearwards, formed in a periphery of the drill body on its front side, said chip evacuating flutes having rake faces that face a drill rotating direction, and
at least one cutting edge formed along a ridge line where the front flanks intersect with the rake faces; and
flank-flute connection portions, each of which is formed between the front flank and the chip evacuating flute in the drill rotating direction; wherein

at least first and second front flanks are formed on the front flanks in order of their locations in the drill rotating direction from its leading side to its trailing side,
a clearance angle of the second front flank is greater than that of the first front flank,
an intersection line of the first and second front flanks crosses the cutting edge,
at least one third front flank is formed adjacent to the second front flank in the trailing direction of the drill rotating direction,
an intersection line of the second and third front flanks crosses the axis, and
each of the flank-flute connection portions is provided adjacent to the third front flank in the trailing direction of the drill rotating direction.

2. The drill according to claim 1 , wherein
a thinning edge is formed on an inner periphery side of the cutting edge; and
the intersection line of the first and second front flanks crosses the thinning edge.

3. The drill according to claim 1 , wherein
a thinning edge is formed on an inner periphery side of the cutting edge; and
the intersection line of the first and second front flanks crosses the cutting edge in an outer periphery side from the thinning edge.

4. The drill according to claim 1 , wherein the cutting edge has at least one convex portion and at least one concave portion.

5. The drill according to claim 4 , wherein
the convex portion is provided at a leading side of the drill rotating direction, and
the concave portion is provided at an inner peripheral side of the convex portion and is smoothly connected to the convex portion.

Assignees

• Yanagida Kazuya
• Naruke Koichiro
• Mitsubishi Materials Corp

Inventors

• Yanagida Kazuya
• Naruke Koichiro

Classifications

• B23B2251/082

  Curved cutting edges · CPC title

• B23B51/00 Primary

  Tools for drilling machines · CPC title

• Y10T408/9097

  Spiral channel · CPC title

• B23B2251/14

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

• B23B51/02 Primary

  Twist drills · CPC title