Drill
US-2016144436-A1 · May 26, 2016 · US
Small-diameter drill
US9522428B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-9522428-B2 |
| Application number | US-201314434904-A |
| Country | US |
| Kind code | B2 |
| Filing date | Oct 24, 2013 |
| Priority date | Oct 25, 2012 |
| Publication date | Dec 20, 2016 |
| Grant date | Dec 20, 2016 |
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- Title
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- Abstract
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Abstract
Official abstract text for this publication.
A small-diameter drill having a diameter of φ3 mm or less and an end that has undergone cross thinning is provided such that in a front view, a flute portion cutting edge is curved in concave with a degree of concavity with respect to an imaginary straight line in a range of 0.5 to 2% of a drill diameter, the imaginary straight line connecting the radially outer end of the flute portion cutting edge and the radially outer end of thinning portion cutting edge, the ratio of length of the thinning portion cutting edge to length of the flute portion cutting edge is set to 0.6 to 0.9:1, and in an axially perpendicular cross-sectional view, curvature radius of a heel-side flute surface of the flute is set to be smaller than curvature radius of a flute surface along the flute portion cutting edge.
First claim
Opening claim text (preview).
The invention claimed is: 1. A small-diameter drill having a diameter of φ3 mm or less and an end that has undergone cross thinning, wherein in a front view, a flute portion cutting edge is curved in concave against a rotational direction with respect to an imaginary straight line that connects a radially outer end of the flute portion cutting edge and a radially outer end of a thinning portion cutting edge, a degree of concavity of the flute portion cutting edge with respect to the imaginary straight line is set in a range of 0.5 to 2% of a drill diameter, furthermore, a ratio B:A of a length B of the thinning portion cutting edge to a length A of the flute portion cutting edge is set to 0.6 to 0.9:1, and in an axially perpendicular cross-sectional view, a curvature radius R 1 of a heel-side flute surface of a flute is set to be smaller than a curvature radius R 2 of a flute surface along the flute portion cutting edge. 2. The small-diameter drill according to claim 1 , wherein a radial rake angle γ of a radially outer end of the flute portion cutting edge is set to −5 to −15°. 3. The small-diameter drill according to claim 1 , wherein a core thickness is set to 0.30D to 0.37D and a flute width ratio θ1: θ2 is set to 0.70 to 0.90:1. 4. The small-diameter drill according to claim 1 , wherein the cutting edge has undergone reinforcing treatment of round honing with R radius of 0.005 to 0.015 mm.
Assignees
Inventors
Classifications
Configuration of the drill point · CPC title
Spiral grooves · CPC title
Spiral channel · CPC title
Drills with lubricating or cooling equipment {(B23B51/042 takes precedence)} · CPC title
- B23B51/02Primary
Twist drills · CPC title
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Frequently asked questions
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- What does patent US9522428B2 cover?
- A small-diameter drill having a diameter of φ3 mm or less and an end that has undergone cross thinning is provided such that in a front view, a flute portion cutting edge is curved in concave with a degree of concavity with respect to an imaginary straight line in a range of 0.5 to 2% of a drill diameter, the imaginary straight line connecting the radially outer end of the flute portion cutting…
- Who is the assignee on this patent?
- Sumitomo Electric Hardmetal Corp
- What technology area does this patent fall under?
- Primary CPC classification B23B51/02. Mapped technology areas include Operations & Transport.
- When was this patent published?
- Publication date Tue Dec 20 2016 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 1 related publication on this page (citations in our corpus or others sharing the same primary CPC).