Drill
AssigneeSumitomo Electric Hardmetal Corp.
InventorsMayuka SEGAWA, Machiko ABE, Akihiko UEDA, Yoshinori TANIGAWA, Takashi HARADA
Life of this patent
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Abstract
A drill includes a blade tip part that is formed of diamond and a trunk part that is formed of diamond and is continuous with the blade tip part, the drill rotating about a drill axis, the blade tip part includes N cutting edges where N is an integer of no less than 4, and a proportion of S1 to S2 is no less than 30% and no more than 60%, where S1 is an area of the drill in a cross-section with the drill axis as a normal line, the cross-section including a boundary between the blade tip part and the trunk part, r is a maximum value of a distance from the drill axis to an outer edge of the drill in the cross-section and S2 is an area of a circle with r as a radius.
Claims4
A drill comprising a blade tip part that is formed of diamond and a trunk part that is formed of diamond and is continuous with the blade tip part, the drill rotating about a drill axis, wherein:
- the blade tip part includes N cutting edges where N is an integer of no less than 4;
- each of the N cutting edges includes a corresponding one of N ridges leading to an apex of an N-gonal pyramid, the apex being present on the drill axis;
- and
- a proportion of S1 to S2 is no less than 30% and no more than 60%, where S1 is an area of the drill in a cross-section with the drill axis as a normal line, the cross-section including a boundary between the blade tip part and the trunk part, r is a maximum value of a distance from the drill axis to an outer edge of the drill in the cross-section and S2 is an area of a circle with r as a radius.
Dependencies are inferred from the claim text.