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US 2011/0033255 A1Published application
Gun Drill
AssigneeUnitac, Inc.
InventorTakuji Nomura
Life of this patent
Estimating the term…
Abstract
A gun drill has a cutting blade which attains high cutting efficiency without requiring exact positional accuracy at the time of brazing an associated cutting blade tip onto a cutting head. Thus, the cutting head can be manufactured easily and the cutting blade itself is also easily processed. The cutting blade is configured such that an inner end of a blade edge is spaced apart from a head central axis to form a non-cutting zone in the vicinity of the shaft center, a cutting blade side face at the inner end side constitutes an inclined surface which is inclined from the inner end to the head central axis side, and a uncut core of a work material generated in the non-cutting zone is broken off by press-contact of the inclined cutting blade side face during drilling operations.
Claims16
A gun drill comprising:
- a tool shank;
- a cutting head mounted on a distal end portion of the tool shank, the cutting head having a longitudinally extending head central axis (O) around which the cutting head rotates;
- a coolant supply passage provided inside the tool shank and a coolant supply passage provided inside the cutting head, the two coolant supply passages communicating with one another;
- a coolant discharge port opened at the cutting head and communicating with the coolant supply passage provided inside the cutting head;
- a cutting chip discharge groove provided on an outer circumferential surface and extending lengthwise from a proximal side of the tool shank to a cutting head distal end;
- and
- a cutting blade provided at the cutting head distal end and bordering the cutting chip discharge groove, wherein the cutting blade comprises:
- a blade edge having an inner end spaced apart from the head central axis of the cutting head, whereby the inner end forms a non-cutting zone in the vicinity of the head central axis upon rotation of the gun drill during drilling operations, and
- a cutting blade side face at an inner end side of the cutting blade, the cutting blade side face having an inclined surface which is inclined from the inner end to the head central axis side,
- wherein the inclined surface of the cutting blade side face is configured to press-contact and break off an uncut core generated in the non-cutting zone upon rotation of the gun drill during drilling operations.
7 more elements
A method for cutting a workpiece, comprising:
- providing a gun drill comprising:
- a tool shank;
- a cutting head mounted on a distal end portion of the tool shank, the cutting head having a longitudinally extending head central axis (O) around which the cutting head rotates;
- a coolant supply passage provided inside the tool shank and a coolant supply passage provided inside the cutting head, the two coolant supply passages communicating with one another;
- a coolant discharge port opened at the cutting head and communicating with the coolant supply passage provided inside the cutting head;
- a cutting chip discharge groove provided on an outer circumferential surface and extending lengthwise from a proximal side of the tool shank to a cutting head distal end;
- and
- a cutting blade provided at the cutting head distal end and bordering the cutting chip discharge groove, wherein the cutting blade comprises:
- a blade edge having an inner end spaced apart from the head central axis of the cutting head, whereby the inner end forms a non-cutting zone in the vicinity of the head central axis upon rotation of the gun drill during drilling operations, and
- a cutting blade side face at an inner end side of the cutting blade, the cutting blade side face having an inclined surface which is inclined from the inner end to the head central axis side, and
- drilling the workpiece to thereby form a hole having an uncut core in the non-cutting zone;
- wherein the inclined surface of the cutting blade side face press-contacts and breaks off the uncut core upon rotation of the gun drill during drilling operations.
9 more elements
A gun drill comprising:
- a tool shank;
- a cutting head mounted on a distal end portion of the tool shank, the cutting head having a longitudinally extending head central axis (O) around which the cutting head rotates;
- a coolant supply passage provided inside the tool shank and a coolant supply passage provided inside the cutting head, the two coolant supply passages communicating with one another;
- a coolant discharge port opened at the cutting head and communicating with the coolant supply passage provided inside the cutting head;
- a cutting chip discharge groove provided on an outer circumferential surface and extending lengthwise from a proximal side of the tool shank to a cutting head distal end;
- and
- a cutting blade provided at the cutting head distal end and bordering the cutting chip discharge groove, wherein the cutting blade comprises:
- a single blade edge having an inner end spaced apart from the head central axis of the cutting head, and
- a cutting blade side face at an inner end side of the cutting blade, the cutting blade side face having an inclined surface which is inclined from the inner end to the head central axis side,
- and wherein:
- an entire blade edge of the cutting blade is forwardly inclined toward the head central axis;
- the inner end constitutes the forwardmost portion of the cutting head;
- and
- the head central axis intersects the inclined surface of the cutting blade side face.
11 more elements
Dependencies are inferred from the claim text.