Patent ID: 11872641
Assignee: KYOCERA CORPORATION
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A drill, comprising:
a main body having a bar shape extending from a first end to a second end, the main body configured to rotate around a rotation axis, and comprising:
a cutting edge located at a side of the first end,
a first flute extending from the cutting edge toward the second end, and
a second flute extending from the first flute toward the second end,

wherein
the first flute comprises a chip formation surface configured to smoothly curl chips, the chip formation surface comprising, in a first cross section orthogonal to the rotation axis,
a first portion having a concave curvilinear shape located at a more rear side of the first flute in a rotation direction of the rotation axis than a bottom of the first flute, and
a second portion having a convex curvilinear shape located at a more front side of the first flute in the rotation direction than the bottom of the first flute; and

the second flute has a concave curvilinear shape from a front end portion located at a front side of the second flute in the rotation direction to a rear end portion located at a rear side of the second flute in the rotation direction in a second cross section
orthogonal to the rotation axis.