dial speed change under load, ordered according to the speed, especially for machine tools.

摘要

945,942. Variable-ratio gears. ZAHNBADFABRIK FRIEDRICHSHAFEN A.G. Aug. 12, 1960 [Aug. 12, 1959], No. 28077/60. Heading F2D. A variable-speed gear providing eight ratios and particularly for machine tools comprises a compound planetary train in series with a tworatio planetary train. The gearing comprises suns 26b, 27b fast on an input shaft 21, and meshing planets 26c, 27c respectively meshing ring gears 26a, 27a. The ring gear 26a is stationable by a brake B 1 and clutchable to the input shaft by a clutch K 1 , and the planet carrier 26d of the planets 26c is fast with the ring gear 27a which is stationable by a brake B 2 . The planets 27c are fast with planets 28b which mesh a ring gear 28a stationable by a brake B 3 , and the planet carrier for these planets is fast with a ring gear 29a of a two-ratio train having planets mounted on a carrier fast with an output shaft 24, and a sun gear 29b stationable by a brake B 4 and clutchable by a clutch K 2 to the output shaft 24. Fig. 4 shows which clutches and brakes are engaged to obtain each ratio, an X indicating that that clutch or brake is engaged. It will be noted that in certain shifts, namely second to third, fourth to fifth, and sixth to seventh, four clutches and brakes are involved, and, for example, in shifting from fourth to fifth initially brake B 2 and clutch K 2 are engaged, and in the shift brake B 2 is disengaged and brake B 1 applied, so that momentarily the sixth ratio is obtained, and then the clutch K 2 is disengaged and the brake B 4 applied to give the fifth ratio. In order to avoid the undesired momentary increase in output speed which the momentary engagement of the sixth ratio would entail, the driving motor, which is a variable-speed electric motor has its speed temporarily reduced to avoid such an undesired increase in output speed.