Zero lead generative cutting tool
AssigneeCaterpillar Inc.
InventorGabriel J. Ellicott
Life of this patent
Estimating the term…
Abstract
A hobbing or gear cutting machine uses a rotary tool to rotate a cutting tool around a central axis of the cutting tool. The cutting tool has zero lead cutters, that is, the cutting tool is non-helical. A head holds the rotary tool and moves the cutting tool longitudinally along the central axis of the cutting tool. A workpiece holder holds a workpiece to be machined into a gear proximate the cutting tool. The workpiece holder selectively rotates the workpiece in conjunction with the longitudinal movement of the cutting tool via the head to cut both straight and helical gears from the workpiece.
Claims17
A gear cutting tool, comprising:
- a head that is programmably moveable in three axes;
- a rotary tool mounted to the head;
- a cutting tool with cutters having a zero lead angle, the cutting tool attached to the rotary tool so that as the rotary tool spins the cutting tool about a cutting tool central axis, the cutting tool and the rotary tool are moveable in three dimensions;
- a workpiece holder that holds a workpiece proximate to the cutting tool, the workpiece holder configured to rotate the workpiece about a workpiece axis in conjunction with at least one dimension of movement of the cutting tool;
- a head rotator that reorients the cutting tool central axis radially about an axis of rotation of the head rotator;
- a controller that coordinates independent motion of the head, the head rotator, and the workpiece holder according to a desired gear profile;
- and
- wherein a cutting motion sequence of the cutting tool with respect to the workpiece is repeated at one of a deeper cut or an offset to make a higher tolerance gear tooth.
A method of cutting gears, comprising:
- providing a cutting tool with cutters having a zero lead angle;
- orienting the cutting tool with respect to a workpiece;
- rotating the cutting tool about a central axis of the cutting tool;
- engaging the cutting tool with the workpiece to cut gear teeth into the workpiece;
- shifting the cutting tool along the central axis of the cutting tool;
- rotating the workpiece while shifting the cutting tool along the central axis of the cutting tool;
- feeding the cutting tool axially along an axis parallel to a central rotation axis of the workpiece and perpendicular to the central axis of the cutting tool while engaging the workpiece;
- and
- when a contact point between the cutting tool and the workpiece reaches one end of the cutting tool, indexing the cutting tool to reestablish the contact point of the workpiece with an opposite end of the cutting tool.
A gear cutting tool, comprising:
- a head that is programmably moveable in three axes;
- a rotary tool mounted to the head;
- a cutting tool with cutters having a zero lead angle, the cutting tool attached to the rotary tool so that as the rotary tool spins the cutting tool about a cutting tool central axis, the cutting tool and the rotary tool are moveable in three dimensions;
- a workpiece holder that holds a workpiece proximate to the cutting tool, the workpiece holder configured to rotate the workpiece about a workpiece axis in conjunction with at least one dimension of movement of the cutting tool;
- a head rotator that reorients the cutting tool central axis radially about an axis of rotation of the head rotator;
- a controller that coordinates independent motion of the head, the head rotator, and the workpiece holder according to a desired gear profile;
- wherein the controller moves the cutting tool perpendicular to a tooth line of the workpiece;
- and
- wherein when a contact point between the cutting tool and the workpiece is at one end of the cutting tool, the controller i) disengages the cutting tool from contact with the workpiece, ii) resets the cutting tool to establish the contact point using an opposite end of the cutting tool, and iii) restarts the motion of the cutting tool and the workpiece holder.
Dependencies are inferred from the claim text.