Improvements in or relating to checking the precision of toothed wheels, worms wheels and other wheels and gears

摘要

836,368. Checking accuracy of gears. VYZKUMNY USTAV OBRABECICH STROJU A OBRABENI. March 7, 1957 [March 16, 1956; April 29,1956], No. 7679/57. Class 40 (1). The accuracy of gears is checked by coupling a magnetic gauge to move with each of the engaging gears, picking off an alternating voltage by movement of the gauges relative to a sensing head and comparing the two voltages so obtained. In Fig. 2, the gears 4 and 5 are mounted on spindles 1, 6 which also carry discs 2, 7 (see Specification 824,653) on which are recorded magnetic signals. As the discs rotate, the heads 11, 10 generate voltages whose frequencies are in the same ratio as the instantaneous gear ratio of the wheels 4, 5. The voltages are amplified and converted at 12, 13 into pulses of repetition rate proportional to the frequencies of the picked-up signals (e.g. four times as great). The pulses of higher rate are passed into the divider 14 and reduced to a rate which will be equal to that of the pulses from 12 if both gears are perfect. The frequency divider 16 then produces no output. Any irregularity in the gears causes the instantaneous pulse rate to change, giving an output on the indicator 17. Alternatively (Fig. 1, not shown), the irregularities are shown as phasedifferences of the two voltages. The method is also applicable to worm gearing, friction gearing, rack-and-pinion gearing or lead-screws and nuts.