GB1302765A - An apparatus for measuring the accuracy of the involute of toothed wheels - Google Patents

Abstract

1302765 Testing involute toothed gear-wheels VYZKUMNY USTAV OBRABECICH STROJU A OBR‰BENI 17 Feb 1970 [18 Feb 1969] 7628/70 Heading G1N The accuracy of the involute surface of the teeth of a gear-wheel 14 Fig.1 is determined by contacting the surface with a feeler 22 carried by a roller 13 driven by a motor 15 via wormgears 2 and 3. The errors in the worm-gear 2, 3 are measured by a selsyn 8 whose rotor is driven by the motor 15 and whose stator windings are fed with quadrature signals derived from a fixed pick-up 5 associated with a series of marks on a disc 4 driven independently by a motor 7. The number of marks corresponds to the gear ratio 2, 3 so that the frequency of the signal in the rotor winding of selsyn 8 is equal to that from a pick-up 6 rotating with roller 13 and any phase differences, measured by phase comparator 10 Fig.2, represent errors in the worm-gear 2, 3. The errors in the overall system are similarly measured by a selsyn 8' and pick-ups 5', 6', any phase differences between the signal in pickup 6' and the signal in the rotor winding of selsyn 8' being due to errors in gears 17, 18, gears 2, 3 and in the involute surface of the teeth of gearwheel 14, sensed by feeler 22. The errors in gears 17, 18 are negligible, and the errors in gears 2, 3 are eliminated by obtaining at 20 the difference between the outputs of selsyns 8, 8', whereby the output from mixer 20 represents the errors of the involute surface of the teeth of gearwheel 14 and are indicated at 12.