GB795605A - Gear finishing with lead correction - Google Patents

Abstract

795,605. Gear-finishing; milling-cutters. NATIONAL BROACH & MACHINE CO. Nov. 13, 1956 [Jan. 16, 1956], No. 34637/56. Class 83 (3). A method of cross-axis gear-shaving to correct lead-errors consists in relatively feeding a narrow cutter radially of the gear along the common normal at the centre of the gear while positively rotating one of them, and successively relatively traversing them by increasing distances until the width of the gear has been machined, there being an additional radial feed between each traverse. The cutter teeth, Fig. 5, have a hollow-lead modification. After the first in-feed, and before traverse takes place, each cutter-tooth 63, shown in an exaggerated section in Fig. 6, cuts into the adjacenttoothflanks along approximately the correct, desired, helical-lead. Traverse is then carried out between the limits indicated in dotted lines. A further radial in-feed is then effected to fulldepth as in Fig. 7, with the cutter in one of its end positions, or in its central position as shown. Traverse is then carried out as indicated by the lines 63a, 63b to completely machine the gear. The cutter may be modified by the provision of a relieved portion in the centre of each tooth, or by providing relatively wide grooves between the lands. The end surfaces of each tooth may have cutting edges or may be chamfered. The radial feed may be rapid and may be combined with traverse.