Method of producing shaving cutter

A method of producing a shaving cutting comprising the steps of:

• preparing a metal blank including a base shaft and a continuous helical thread on the outer periphery of said base shaft;
• rotating said base shaft continuously at a constant speed;
• reciprocating a cutting tool toward and away from said base shaft and laterally moving said cutting tool continuously parallel to said base shaft to form a plurality of cutting grooves on a flank of said thread, said cutting grooves extending from an inner end adjacent to said base shaft to an outer end radially outwardly away from the shaft so that the cutting grooves are inclined at angles between 15.degree. and 90.degree. relative to lines extending radially outwardly from said base shaft in the direction opposite to the rotational direction of the shaft for shaving, said cutting grooves respectively defining lands therebetween having cutting edges at leading edges thereof for cutting teeth surfaces of a gear to be shaved;
• and
• controlling said lateral and reciprocal movement of said cutting tool to synchronize with rotation of said base shaft, said reciprocal movement of said cutting tool being actuated by rotation of a cam member associated with said base shaft,
• said cam member having a cam contour which exhibits a depression .DELTA.S from the maximum radius given by the following equation as the cam member is rotated by an angle .theta., in order to form arcuate cutting edges each of which is centered at a desired point on said metal blank,
• [(Ro-.DELTA.S) cos .theta.+l cos .xi.+m sin .xi.-Ro].sup.2 +[(Ro-.DELTA.S) sin .theta.+m cos .xi.-l sin .xi]sup.2 =R.sup.2
• wherein R represents a radius of said arcuate cutting edge;
• Ro represents a radius of said thread;
• .xi. represents an angle formed between the chord of the arc of said cutting edge and a radial line from said base shaft;
• .DELTA.S represents the depression of a desired point on said arc from its periphery;
• .theta. represents the central angle of said base shaft between said desired point and a point at which the outer periphery of said thread intersects said arc;
• m represents the distance between the mid point of said chord and the center of said arc;
• l represents the half length of said chord.

A method of producing a shaving cutter comprising the steps of:

• preparing a metal blank including a base shaft and a continuous helical thread on the outer periphery of said base shaft;
• rotating said base shaft continuously at a constant speed;
• reciprocating a cutting tool toward and away from said base shaft and laterally moving said cutting tool continuously parallel to said base shaft to form a plurality of cutting grooves on a flank of said thread, said cutting grooves extending from an inner end adjacent to said base shaft to an outer end radially outwardly away from the shaft so that the cutting grooves are inclined at angles between 15.degree. and 90.degree. relative to lines extending radially outwardly from said base shaft in the direction opposite to the rotational direction of shaft for shaving, said cutting grooves respectively defining lands therebetween having cutting edges at leading edges thereof for cutting teeth surfaces of a gear to be shaved;
• and
• controlling said lateral and reciprocal movement of said cutting tool to synchronize with rotation of said base shaft, said reciprocal movement of said cutting tool being actuated by rotation of a cam member associated with said base shaft,
• said cam member having a cam contour which exhibits a depression .DELTA.S from the maximum radius given by the following equation as the cam member is rotated by an angle .theta., in order to form straight cutting edges on said thread ##EQU3## wherein Ro represents a radius of said thread;
• .xi. represents an angle formed between the cutting edge and the radial line at the outer extremity of said cutting edge;
• .theta. represents a central angle of said base shaft between a desired point on said cutting edge and the outer extremity of said cutting edge;
• and .DELTA.S represents the depression of the desired point on said cutting edge.