GB406730A - Improvements in the method of, and apparatus for, cutting toothed gears - Google Patents

Abstract

406,730. Toothed gearing. KLINGELNBERG, G. A., KLINGELNBERG, M., KLINGELNBERG, R. G., KLINGELNBERG, W. H., and KLINGELNBERG, H. W.,(trading as KLINGELNBERG SOHNE, W. F.), 56, Berghauserstrasse, Remscheid, Berghausen, Germany. Aug. 26, 1932, No. 23939. Convention date, Aug. 28, 1931. [Class 80 (i).] Spur or helical gears having teeth, Fig. 1, which are wider at a central section than at the ends so that the zone of contact 1 between intermeshing gears may shift to locations such as 2 and 3 when the gears are incorrectly aligned are cut by means of a hob 22 which is fed tangentially across the work as shown in Fig. 6. The gear may also be cut with a smaller pressure angle at the driving faces than at the driven faces so that a grinding or lapping tolerance is given to those portions of the profile which have the largest sliding velocities. The gears are cut by single or multiple threaded hobbing cutters. Two cutters of opposite hands are used for cutting conjugate gears. The cutters have preferably a cylindrical addendum surface, Fig. 3, but in section the pitch line 16 and the dedendum line 17 are of concave curvature. The teeth are all perpendicular to the cutter axis, but when gears having opposite faces of different pressure angles are to be cut the pressure angles of opposite sides 19, 21, Fig. 5, of the hob teeth are modified accordingly. The differences between the pressure angles alpha and # depends on the material of the gear, being greater for gears which are to be hardened and ground after cutting. The hob 22 is arranged at the required angle to the blank axis and is fed tangentially to the blank, Fig. 6. By slightly tilting the cutter relatively to the blank, the widest part of the teeth cut on the blank may be shifted towards one end of the gear, so that a non-central contact zone between intermeshing gears may be obtained.