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1. (WO2018021580) DRILL MAIN BODY FOR CUTTING EDGE REPLACEABLE DRILL AND CUTTING EDGE REPLACEABLE DRILL

Pub. No.:    WO/2018/021580    International Application No.:    PCT/JP2017/027699
Publication Date: Fri Feb 02 00:59:59 CET 2018 International Filing Date: Tue Aug 01 01:59:59 CEST 2017
IPC: B23B 51/06
B23B 51/00
Applicants: MITSUBISHI MATERIALS CORPORATION
三菱マテリアル株式会社
Inventors: USUI Masahiro
臼井 正洋
NARUKE Koichiro
成毛 康一郎
MATSUNAGA Kohei
松永 光平
KAWADE Yasuhiko
川出 保彦
Title: DRILL MAIN BODY FOR CUTTING EDGE REPLACEABLE DRILL AND CUTTING EDGE REPLACEABLE DRILL
Abstract:
This drill main body for a cutting edge replaceable drill has a chip discharge groove (8) provided with: a tip-side twisted part (8a); a base end-side twisted part (8b) having a twist angle smaller than the twist angle (θ) of the tip-side twisted part (8a); and an intermediate twisted part (8c) disposed between the tip-side twisted part (8a) and the base end-side twisted part (8b). A coolant hole (10) is provided with a first coolant hole (11) and a second coolant hole (12). The first coolant hole (11) opens to a base end surface (9) of the drill main body (2) or to a recessed portion formed in the base end surface (9) and extends, as approaching the tip side in the axial line (O), in a straight line-shape so as to face the drill rotating direction. The second coolant hole (12) is connected to the tip portion of the first coolant hole (11), extends in a straight line-shape toward the tip side of the drill main body (2) from the tip portion in a direction other than the extension direction of the first coolant hole (11), and opens into the chip discharge groove (8) at a position closer to the tip side than is the tip position of the base end-side twisted part (8b).