GB915922A - Improvements relating to planetary change-speed gears - Google Patents

Abstract

915,922. Variable-speed epicyclic gearing. DAIMLER-BENZ A.G. March 7, 1961, No. 8283/61. Class 80 (2). Two reduced forward ratios, direct-drive and one reverse, are provided in a motor-vehicle change-speed gear by two identical or different first and second sun-ring planet trains A, B, the first planet-carrier 19 and second ring gear 15 of which are fast on an output shaft 20, ratio selection being effected by applying friction disc brakes C, D to the connected suns 10, 14 and second planet-carrier 24, respectively, whilst selectively clutching at F and input drum 30 fast on an input shaft 22 to the first ring gear 12 for all forward ratios, or at E to the connected suns 10, 14 for reverse. Ratios are as follows : FIRST, clutch F and brake D. The first ring gear 12 drives, the second planetcarrier 24 takes reaction, and the trains act compounded. SECOND, clutch F and brake C. The connected suns are braked and the front train A acts alone. THIRD, clutches F and E for lock-up direct drive. REVERSE, clutch E and brake D. The rear planet-carrier 24 is held, the suns drive and the rear train B acts alone. The friction clutches and brakes are all engaged by hydraulic pressure, and in one embodiment (Fig. 2, not shown) the clutch E and brake C as well as the clutch F and brake D are identical and mirror-images of each other. The brake C and clutch E of the connected suns are arranged on opposite ends of a cylindrical drum 18 which at the rear overlaps an inner drum 25 of the brake D, and at the front overlaps internally the input drum 30. The gear is driven through a friction clutch or hydrodynamic torque converter.