Deep-hole drill having back-tapered web
AssigneeOsg Corporation
InventorTakahiro Yamamoto
Life of this patent
Estimating the term…
Abstract
A drill having a web which is provided by a central portion of a cylindrical main body of the drill and which includes a back-tapered portion and a constant-thickness portion. The cylindrical main body has a large diameter portion and a small diameter portion contiguous to the large diameter portion, such that a step is provided between the large and small diameter portions. The large diameter portion provided by the axially distal end portion of the cylindrical main body has an axial length which is larger than an axial length of the back tapered portion of the web provided by the axially distal end portion of the web, such that a boundary between the back-tapered portion and the constant-thickness portion of the web is located in the large diameter portion of the cylindrical main body.
Claims11
A drill which comprises a cylindrical main body and a shank contiguous to each other, and which is to be rotated about an axis of said cylindrical main body in a predetermined rotating direction, for drilling a hole in a workpiece, wherein said cylindrical main body has:
- at least one flute each of which is formed in said cylindrical main body and extends from an axially distal end of said cylindrical main body to an axially proximal end of said cylindrical main body, so as to provide a cutting edge at said axially distal end of said cylindrical main body;
- at least one land each of which is provided by a peripheral portion of said cylindrical main body not cut away by said at least one flute;
- and
- a web provided by a central portion of said cylindrical main body which extends in an axial direction of said cylindrical main body;
- wherein said web includes a back-tapered portion which is provided by at least an axially distal end portion of said web, such that a thickness of said web in said back-tapered portion is continuously reduced as viewed in a direction away from said axially distal end of said cylindrical main body toward said shank,
- wherein said web further includes a constant-thickness portion which is contiguous to said back-tapered portion and which is provided by at least an axially proximal end portion of said web, such that the thickness of said web in said constant-thickness portion is constant,
- wherein said cylindrical main body has a large diameter portion provided by an axially distal end portion thereof, and a small diameter portion contiguous to said large diameter portion and having a diameter that is smaller than a diameter of said large diameter portion, such that a step is provided between said large and small diameter portions,
- and wherein said large diameter portion provided by said axially distal end portion of said cylindrical main body has an axial length which is larger than an axial length of said back tapered portion of said web provided by said axially distal end portion of said web, such that a boundary between said back-tapered portion and said constant-thickness portion of said web is located in said large diameter portion of said cylindrical main body.
Dependencies are inferred from the claim text.