| 摘要 |
PURPOSE:To form the cutting edges with high precision by setting the center line of the hob to be a tangent line of the base cylinder for the involute curves to form cutting edges and to be parallel to the slopes of the helical grooves and by feed-shifting following the helical grooves in the direction parallel to the rotation of the cutter. CONSTITUTION:In the state in which the contact points of a hob 11, with a lead equal to the interval of the points where an arbitrary tangent line T to a base circle D of involute curves I intersects each involute curve I, and the slopes of helical grooves of a cutter 3 are made to coincide with the tangent line T, cutting edges 2 are notched successively. The slopes of helical grooves of the cutter 3 are not perpendicular to its center line O, and so the center line of the hob 11 is in parallel with the slopes being tangent to the base cylinder D. After setting the position of a hob head 25 to go up and down with respect to a column 24 and the position of the column 24 to turn with respect to a saddle 23, when the motor is operated, the cutter 3 rotates and the hob 11 also rotates simultaneously with this cutter and moves following grooves 1; thus a cutting edge 2 is formed on the slope of the groove. |
