×

Drill and drilling method for workpiece

  • US 9,180,531 B2
  • Filed: 12/23/2008
  • Issued: 11/10/2015
  • Est. Priority Date: 12/23/2008
  • Status: Active Grant
First Claim
Patent Images

1. A drill comprising:

  • a cutting edge,wherein the cutting edge has a point angle which is continuously decreased from a center-position point angle A at a center position to a maximum-diameter-position point angle of 0°

    at a maximum diameter position,wherein the cutting edge has a radial relief angle which is continuously decreased from the center position to the maximum diameter position,wherein the point angle A at the center position satisfies the condition 0°

    <

    A<

    180°

    , andwherein an axial relief angle at the center position is δ

    , and the center-position point angle A and the center-position axial relief angle δ

    satisfy a relationship of δ

    >

    (180°



    A)/2.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×