Drill
AssigneeKYOCERA Corporation
InventorsMasahiko Kuroda, Yoji Nakazono
Life of this patent
Estimating the term…
Abstract
The drill (1) is provided with a drill body (2) having a rotation center axis (O), two cutting edges (3) provided on the tip side of the drill body (2), and chip evacuation flutes (10) provided behind the two cutting edges (3) in the direction of rotation of the drill (1) from the two cutting edges, the drill tip angle (α) being from 170 to 190°, the web thickness (d) being from 0.10 to 0.25 times the drill diameter (D), the opening angle (γ) of the chip evacuation flutes (10) being from 85 to 110°, and the drill (1) comprising a curve having a radius of curvature that gradually decreases from the cutting edge side wall surface (14) to the heel side wall surface (15) of the chip evacuation flutes (10) in a cross-section at a position where the chip evacuation flutes (10) are present.
Claims11
A drill, comprising:
- a drill body comprising a rotation center axis;
- two cutting edges provided on a tip side of the drill body;
- a chip evacuation flute provided to a rear of the two cutting edges and in a drill rotational direction from each of the two cutting edges;
- and
- two heels provided in a drill counter rotation direction from the two cutting edges;
- in a cross-section orthogonal to the rotation center axis at a position axially rearward of the cutting edge where the chip evacuation flute is present, a radius of curvature of the chip evacuation flute continuously becoming smaller from a first outer peripheral end of a cutting edge side wall surface at a position on a cutting edge side to a second outer peripheral end of a heel side wall surface at a position on a heel side.
A drill, comprising:
- a body having a rotational axis at a center thereof in a cross section that is perpendicular to the rotational axis, and comprising:
- a front tip;
- a rear end;
- a boundary between the front tip and the rear end;
- and
- a side surface between the front tip and the boundary;
- and
- a flute in spiral at the side surface,
- the drill further comprising, in the cross section at the side surface positioned axially rearward of the front tip, a boundary line between the body and the flute,
- the boundary line comprising:
- a first end at a first intersection of the side surface, having a first curvature radius;
- a second end at a second intersection of the side surface, having a second curvature radius;
- and
- a middle point between the first end and the second end, having a third curvature radius, wherein
- the first curvature radius is larger than the third curvature radius, and
- the third curvature radius is larger than the second curvature radius.
Dependencies are inferred from the claim text.