Drill

Patent metadata

Field	Value
Publication number	US-10850333-B2
Application number	US-201916420242-A
Country	US
Kind code	B2
Filing date	May 23, 2019
Priority date	Jun 6, 2018
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

A drill including: a chip discharge groove formed in an outer periphery of an edge portion serving as a leading end side portion of a drill body; and a cutting edge formed in an intersecting edge between a rake surface of a leading end side region and a leading end flank of the edge portion. The drill having a margin portion, a shoulder portion and a web thinning portion. The cutting edge includes, in order from a rotation center, first cutting edge, second cutting edge, shoulder cutting edge, and margin cutting edge portions. Honing widths of the second cutting edge, the margin cutting edge, and the shoulder cutting edge portions satisfy a relation represented by expression (1), as follows: honing width of the shoulder cutting edge portion>honing width of the margin cutting edge portion≥honing width of the second cutting edge portion.

First claim

What is claimed is:

1. A drill in which: a chip discharge groove which extends toward a base end is formed in an outer periphery of an edge portion serving as a leading end side portion of a drill body rotated around an axis; and a cutting edge is formed in an intersecting edge between a rake surface of a leading end side region of an inner wall surface of the chip discharge groove and a leading end flank of the edge portion, such inner wall surface facing forward with respect to a drill rotating direction, the drill comprising:
a margin portion intersecting with the rake surface and facing toward the outer periphery;
a shoulder portion being an intersecting edge between the margin portion and the leading end flank of the edge portion and extending, from an outer peripheral end of the cutting edge, backward with respect to the drill rotating direction; and
a web thinning portion extending toward a leading end of the inner wall surface of the chip discharge groove, wherein:
the cutting edge comprises, in order from a rotation center, a first cutting edge portion formed in the web thinning portion, a second cutting edge portion formed closer to the outer periphery than the first cutting edge portion, a shoulder cutting edge portion formed in the shoulder portion, and a margin cutting edge portion formed in the margin portion;
honing is performed on the second cutting edge portion, the margin cutting edge portion and the shoulder cutting edge portion; and
honing widths of the respective portions satisfy a relation represented by the expression:
the honing width of the shoulder cutting edge portion>the honing width of the margin cutting edge portion≥the honing width of the second cutting edge portion.

2. The drill according to claim 1 , wherein the honing width of the shoulder cutting edge portion is from 80 μm or more to 200 μm or less.

3. The drill according to claim 1 , wherein the honing width of the margin cutting edge portion is from 60 μm or more to 180 μm or less.

4. The drill according to claim 1 , wherein the honing width of the second cutting edge portion is from 30 μm or more to 150 μm or less.

5. A coated drill having a coated layer formed on a surface thereof, in which:
a chip discharge groove which extends toward a base end is formed in an outer periphery of an edge portion serving as a leading end side portion of a drill body rotated around an axis;
and a cutting edge is formed in an intersecting edge between a rake surface of a leading end side region of an inner wall surface of the chip discharge groove and a leading end flank of the edge portion, such inner wall surface facing forward with respect to a drill rotating direction, the coated drill comprising:
a margin portion intersecting with the rake surface and facing toward the outer periphery;
a shoulder portion being an intersecting edge between the margin portion and the leading end flank of the edge portion and extending, from an outer peripheral end of the cutting edge, backward with respect to the drill rotating direction; and
a web thinning portion extending toward a leading end of the inner wall surface of the chip discharge groove, wherein:
the cutting edge comprises, in order from a rotation center, a first cutting edge portion formed in the web thinning portion, a second cutting edge portion formed closer to the outer periphery than the first cutting edge portion, a shoulder cutting edge portion formed in the shoulder portion, and a margin cutting edge portion formed in the margin portion;
honing is performed on the second cutting edge portion, the margin cutting edge portion and the shoulder cutting edge portion; and
honing widths of the respective portions satisfy a relation represented by the expression:
the honing width of the shoulder cutting edge portion>the honing width of the margin cutting edge portion≥the honing width of the second cutting edge portion.

6. The coated drill according to claim 5 , wherein the coating layer comprises a compound layer containing a compound of: an element of at least one kind selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al and Si; and an element of at least one kind selected from the group consisting of C, N, O and B.

7. The coated drill according to claim 5 , wherein the coating layer comprises a composite compound layer containing a compound having a composition represented by expression (2) below:
(Al 1-x Cr x )N  (2)

(wherein x denotes an atomic ratio of the Cr element based on a total of the Al element and the Cr element and satisfies 0.10≤x≤0.50).

8. The coated drill according to claim 5 , wherein an average thickness of the entire coating layer is from 0.5 μm or more to 8.0 μm or less.

9. The drill according to claim 2 , wherein the honing width of the margin cutting edge portion is from 60 μm or more to 180 μm or less.

10. The drill according to claim 2 , wherein the honing width of the second cutting edge portion is from 30 μm or more to 150 μm or less.

11. The drill according to claim 3 , wherein the honing width of the second cutting edge portion is from 30 μm or more to 150 μm or less.

12. The drill according to claim 9 , wherein the honing width of the second cutting edge portion is from 30 μm or more to 150 μm or less.

13. The coated drill according to claim 6 , wherein the coating layer comprises a composite compound layer containing a compound having a composition represented by expression (2) below:
(Al 1-x Cr x )N  (2)

(wherein x denotes an atomic ratio of the Cr element based on a total of the Al element and the Cr element and satisfies 0.10≤x≤0.50).

14. The coated drill according to claim 6 , wherein an average thickness of the entire coating layer is from 0.5 μm or more to 8.0 μm or less.

15. The coated drill according to claim 7 , wherein an average thickness of the entire coating layer is from 0.5 μm or more to 8.0 μm or less.

16. The coated drill according to claim 13 , wherein an average thickness of the entire coating layer is from 0.5 μm or more to 8.0 μm or less.

17. A drill in which: a chip discharge groove which extends toward a base end is formed in an outer periphery of an edge portion serving as a leading end side portion of a drill body rotated around an axis; and a cutting edge is formed in an intersecting edge between a rake surface of a leading end side region of an inner wall surface of the chip discharge groove and a leading end flank of the edge portion, such inner wall surface facing forward with respect to a drill rotating direction, the drill comprising:
a margin portion intersecting with the rake surface and facing toward the outer periphery;
a shoulder portion being an intersecting edge between the margin portion and the leading end flank of the edge portion and extending, from an outer peripheral end of the cutting edge, backward with respect to the drill rotating direction; and
a web thinning portion extending toward a leading end of the inner wall surface of the chip discharge groove, wherein:
the cutting edge comprises, in order from a rotation center, a first cutting edge portion formed in the web thinning portion, a second cutting edge portion formed closer to the outer periphery than the first cutting edge portion, a shoulder cutting edge portion formed in the shoulder portion, and a margin cutting edge portion formed in the margin portion;
honing is performed on the second cutting edge portion, the margin cutting edge portion and the shoulder cutting edge portion; and
honing widths of the respective portions satisfy a relation represented by the expressi

Assignees

• Tungaloy Corp

Inventors

• Katagiri Takao

Classifications

• B23B2251/02

  Connections between shanks and removable cutting heads · CPC title

• B23B51/02 Primary

  Twist drills · CPC title

• B23B2251/12

  Cross sectional views of the cutting edges · CPC title

• B23B2228/105

  with specified thickness · CPC title

• B23B2260/072

  Grooves · CPC title