DRILL - MITSUBISHI MATERIALS CORP

Title:

DRILL

Document Type and Number:

WIPO Patent Application WO/2017/034038

Kind Code:

A1

Abstract:

Thinning rake faces (6a) are formed on the tip part of a drill bit body (1) rotating about an axis (O) such that intersecting edge lines of the thinning rake faces with tip flank faces (2) form thinning cutting edges (4a), and first thinning wall faces (6b) continuous with thinning rake faces (6a) and second thinning wall faces (6c) continuous with the first thinning wall faces (6b) are formed on the opposite side of chip discharge grooves (3) to the drill rotation direction (T). When looked at from the tip side in the axial direction (O), the intersecting angle of each thinning cutting edge (4a) with a first thinning edge line (L1) is larger than 95 degrees, a second thinning edge line (L2) is bent opposite to the drill rotation direction (T) with respect to the first thinning edge line (L1), the thinning cutting edge (4a) and the first thinning edge line (L1) are continuous with each other via a concave curved line (N1), the first and second thinning wall faces (6b, 6c) are continuous with each other via a concave curved face, and the curvature radius (R1) of the concave curved line (N1) is smaller than the curvature radius (R2) of the concave curved face.

Inventors:

YAMAMOTO TADASHI (JP)
YANAGIDA KAZUYA (JP)
TSURUMAKI YUYA (JP)

Application Number:

PCT/JP2016/075153

Publication Date:

March 02, 2017

Filing Date:

August 29, 2016

Export Citation:

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Assignee:

MITSUBISHI MATERIALS CORP (JP)

International Classes:

B23B51/00; B23B51/06

Domestic Patent References:

WO2014116575A1

2014-07-31

Foreign References:

JP2009269167A	2009-11-19
JP2005169572A	2005-06-30
JP2005001082A	2005-01-06

Other References: