Patent GB-1474159-A (GB)
Title: Gear grinding machine
IPC: B23F5/06
Filed: 1975-10-03
Abstract: 1474159 Grinding gears; machine tool details HURTH VERWALTUNGS GmbH 3 Oct 1975 [13 Dec 1974] 40546/75 Headings B3K and B3B A gear grinding machine comprises a grinding wheel 19 mounted on a head 20, a workpiece support shaft 4, Fig. 2, a dividing head 7 coupled to the shaft for rotating the shaft to bring the flanks of successive teeth of a gear into engagement with the grinding wheel, a driving drum carriage 2 reciprocatable to move the shaft transverse to its axis, a driving drum 8 associated with the shaft for turning the shaft through a required angle during a grinding operation, driving bands 9, 10 for imposing turning motion to the drum upon reciprocation of the carriage, and means 35, 40 for imparting a supplementary transverse turning motion to the workpiece relative to the grinding wheel during the grinding operation without substantially modifying the load on the band. The carriage 2 is reciprocatably slidable by known means on the frame of the machine in a direction transverse to the axis of the shaft 4 which, at one end, mounts the gear 5 to be ground, and, at the other end has a dividing head 7 coupled to the sleeve 6 of the driving drum 8 and the shaft 4. The drum is connected by bands 9, 10 to a holder 12 slidable transversely of the shaft 4 on a jib member 13 which has one end vertically adjustable along a slide 15 by a screw 16 and clampable by bolts 17 and the other end lockably supported in a holder 38. A sine bar 35 is adjustable about a pivot on the carriage 2 by a micrometer screw 36 and is engaged by one arm 40 of a ball crank lever mounted on a fixed pivot 37, the other arm 41 of the lever engaging holder 12 to effect movement thereof against the pressure of a spring 42 upon movement of the carriage to impart the supplementary movement to the shaft and gear being ground and hence modify the involute shape produced by the bands 9, 10 and drum 8- The movement of the holder is shown by a dial indicator 43 co-operating with a lever 44 moved by the holder. The grinding wheel 19, Fig. 5, is clamped to a spindle 22 which is mounted in bearings 23 in a grill 24 and connected by a flexible coupling 27 to an electric motor 26. The grill is axially adjustable in the head 20 by rotation of a screw 29 engaging a nut 28 formed on the grill, the screw being rotatable through a clutch 32 by gearing 30 driven by manual or motor means. The head 20 is angularly adjustable with respect to the workpiece to determine the pressure angle, and a pedestal 21 is adjustable to the helix angle of the workpiece. In another embodiment, the supplementary transverse movement is produced in the directing means 7. The drum sleeve 6 is connected to a rocker 46, Figs 3 and 4, having a guideway 47 for an indexing carriage 48 having a ratchet slide 49 movable radially and formed with a tooth 50 engaging an indexing disc 56. A rack 51 on the slide 49 engages a pinion 52 rotatable by engagement of a panel 53, upon rotation of the rocker 46, with a pivoted cam 64 to lift the tooth 50 from one tooth gap in the disc 56 into the next. The supplementary movement is effected by movement of the carriage 48 against the pressure of a spring 54 when an eccentric disc 67 is rotated by a drive 68 from a receiver 69 connected to a transmitter operated by movement of a sensor 71 engaging a template 20 on the machine frame. In other embodiments, the carriage 2 and band holder 12 are moved by screws rotated by electric or hydraulic servo motors or stepping motors controlled manually or by punched tape, computer or other systems.