GB586193A - Method and apparatus for shaving gears - Google Patents

Abstract

586,193. Gear - cutting. FELLOWS GEAR SHAPER CO. May 18, 1944, No. 9589. Convention date, May 14, 1943. [Class 83 (iii)] Milling-cutters.-In a method of finishing gear-wheels on the intermeshing generator principle by means of a tool T having cutting edges g on the flanks of the teeth t, which is designed for use on work G having shoulders or other obstructions S, S<1> adjacent the teeth to be cut, the periphery C of the tool and the teeth t are tapered and the tool is rotated in mesh with the work about an axis A inclined to the work axis B. The axes A, B may be inclined to each other in two directions so that they do not lie in parallel planes, as shown in Figs. 2 and 5, and the finishing operation may be performed on an externally toothed gear G, Fig. 2, or an internally toothed gear G<1>, Fig. 5. The larger diameter of the tool is arranged adjacent the shoulder on the work and the teeth t are helical so as to have an axial shaving action on the work on the " crossed axis " principle. The work may have straight teeth as shown or helical teeth, in which case the helical angle of the teeth on the tool may be varied to correspond, and axial reciprocation is imparted to the tool or work to distribute the cutting effect. Alternatively, the tool teeth may be bowed longitudinally as described in Specification 466,330, the curvature being concave for cutting external gears and convex for internal gears, and no axial reciprocation being required in this case unless the work teeth are longer than the cutter teeth. In another form, the inclined axis A of the tool may lie in the same plane as the axis B, Fig. 7, of the work, the teeth t<1> then being straight or helical according to whether the work teeth are straight or helical and a rapid reciprocation in the direction of the work axis then being given to the tool or work. The internal teeth S <1> may also be finished by a tapered tool similar to the tool T<1> rotating on an inclined axis in the same plane as the axis B. A machine for carrying out the process comprises a head 11, Fig. 1, provided with a rotary spindle for supporting the work G and movable on horizontal guides 12 parallel to the spindle. A knee 16, vertically adjustable by a screw 19 hand-operated at 18, carries a compound slide 21, 25 adjustable in transverse directions by hand wheels 23, 26 and a tilting table 27 is adjustable about pivots 28 on the slide 25 by a segmental rack and pinion 30 operated by a hand wheel 31. A turntable 32 is adjustable by a hand wheel 33 and worm 34 about an axis perpendicular to the table 27 and carries the spindle 37 for the tool T which is driven by an electric, hydraulic or other motor 36 on the turntable. In order to reciprocate the work axially relatively to the tool, the head 11 is driven by a connecting rod 48 and adjustable crank 47 from a motor 38 through a belt 40, worm drive 43 and a change-speed device 44.