Patent GB-624769-A (GB)
Title: Improved method of and apparatus for producing toothed face clutches
IPC: B23F15/06
Filed: 1945-05-25
Abstract: 624,769. Grinding teeth of face clutches. ABBEY, A. (Gleason Works). May 25, 1945, No. 13187. [Class 60] [Also in Groups XXII and XXIV] Toothed face clutch members capable of transmitting load when only partially engaged have the teeth chamfered on their top surfaces along helicoidal surfaces, and in a method of producing such chamfered surfaces a cutting tool is moved along the teeth of the work whilst relative rotary movement between the tool and work is produced about the work axis and also relative movement along the work axis at a varying ratio to the rotary movement. In one form a clutch part 60, Figs. 3 and 4, has radial teeth 62 whose flanks 64, 65 are parallel to the clutch axis 63 but concave. whilst the mating clutch part 61 has radial teeth 66 with convex flanks 67, 68 also parallel to axis 63. The teeth 62 are chamfered at 70, 71 on concave surfaces which are common to a circle 77 centered at 75 but the chamfers 72, 73 on teeth 66 are helicoidal convex surfaces which are conjugate to chamfers 70,71. The teeth 62 are produced by a grinding wheel 80, Fig. 4, fed to depth along its axis of rotation 82 which coincides with the centre 75, the edges of the cutter being shaped to produce the flanks and chamfers of the teeth 62. After withdrawal of the cutter the work is indexed for shaping a further pair of tooth sides. The teeth 66 are produced by an annular grinding wheel 90, Fig. 6, or a cup-shaped oscillatory grinding wheel which is rotated or oscillated about its axis 92 whilst the work is fed along its axis 63 to produce the flanks 67, 68, but at the beginning and end of the axial feed the work is also rotated about its axis so that the curved faces 94 of the cutter generate chamfers 72, 73 which are conjugate to chamfers 70, 71 for all positions of partial engagement of the clutch parts. The cross section of the chamfered portions of the teeth may be arcuate and fully rounded or truncated. The teeth have uniform height from end to end and the roots lie on a plane perpendicular to the clutch axis, but in a modification the teeth 132, 156, Figs. 23 and 25, have uniform height but tips and roots lying on conical surfaces 139, 161. To generate these teeth the axis 128 of cutter 125 is inclined to the clutch axis 133 and the clutch part 120 is fed into the rotating cutter along a path 136 slightly inclined to axis 133. The axis 148 of cutter 145 is inclined in the opposite direction and the clutch part 121 has axial feed and rotation in the same manner as clutch part 61 of Fig. 6. The cutter 145 may be of slightly smaller diameter than cutter 125 to produce teeth 156 of greater longitudinal curvature than teeth 132 in order to relieve the pressure on the ends of the teeth when the clutch parts are in partial engagement, but the inclination of cutter axis 148 is less than that of cutter axis 128 to maintain the conical surfaces 139, 161 at the same angle. The tops of teeth 132, 156 may lie on a plane perpendicular to the clutch axis. In a modification of the method of generating teeth 156, the work 121 is fed axially and rotated whilst a chamfer 72a, Fig. 5 is formed and the rotation is continued at a slower rate whilst the depth feed is taking place and is reversed just before full depth is reached in order to finish the tooth flank with the flat face of the cutter tooth. As the work is withdrawn from the cutter, its rotation is again reversed so that a tooth flank 67b, Fig. 5, will be finished and finally the rate of rotation is increased whilst the chamfer 73b is being generated. Grinding-machines; gear-cutting.--In a machine for carrying out the generating process, which may also be used for cutting other types of face clutches or bevel or hypoid gears without generating roll, the work 220, Fig. 41, is carried by a rotatable spindle 221 mounted on vertically horizontally adjustable slides 222, 223. Slide 223 is angularly adjustable on arcuate guides 224 on a slide 225 movable on horizontal guides 228. The cutter 230 is carried by a spindle journalled in a swivel head 231 adjustable about axis 233 perpendicular to the cutter axis on a slide 232 adjustable in direction 235. The relative motions of the machine are produced by the gearing shown in Fig. 43, in which an electric motor 240 rotates the cutter 230 through gearing 246, 250, and also rotates through gearing 260, 262 a cam 264 which operates the slide 225 to feed the work 220 axially for producing the clutch parts 60 or 120. To generate the clutch parts 61 the work shaft 221 is also rotated by means of two Geneva wheels 273, 274 driven simultaneously from the gearing 260, each Geneva wheel having two pins 279 spaced 180 degrees apart which engage slotted members 278, 281 in a differential housing 284 so that the rotations of the two shafts will be compounded in the rotations of the housing, which is connected to the work shaft 221 by gearing 292, 298. With the Geneva wheels out of phase, one will produce a velocity diagram of work rotation as at 218, 214, Fig. 30, whilst the other will produce diagram 211 215, which, when compounded by the differential gear, will produce the full line diagram of Fig. 30. In this, chamfering takes place from 211 to 212, the work remains stationary from 212 to 213, whilst the cutter penetrates to full depth and is withdrawn and cutting of a chamfer on another tooth is performed from 213 to 214. From 214 to 215 the work is indexed, and at 215 chamfering of the next tooth commences. To generate clutch parts 121, Geneva wheel 273 is replaced by one having four pins spaced 90 degrees apart and Geneva wheel 274 is replaced by gearing which drives shaft 283 continuously in the opposite direction to the intermittent rotation of shaft 282. This gives rotation of the work according to the velocity diagram of Fig. 45, in which chamfering commences at 320 and proceeds to 321, feeding to depth takes place from 321 to 325, reversal of rotation for finishing the tooth flank occurs from 325 to 326, withdrawal from 326 to 323, chamfering of another tooth from 323 to 324, and indexing of the work from 324 to 324<SP>1</SP>.  For effecting indexing only of the work, in the production of clutch parts 60, 120, the two Geneva wheels are in phase and each has one tooth only so that the work is indexed during 90 degrees of rotation of shaft 272 and is non-rotating for 270 degrees whilst cutting takes place. By using a Geneva wheel 273 with a single pin and driving shaft 283 through constant velocity gearing which adds to or subtracts from the intermittent rotation of shaft 282, the machine may produce clutch parts having helical flanks on the teeth or saw-shaped teeth with opposite flanks helical and straight respectively. The machine may also be used to produce clutch parts with teeth whose flanks are inclined to the clutch axis, or clutch parts wherein the teeth of each part are longitudinally convex.