GB1429294A - Fixed step and variable transmission - Google Patents

Abstract

1429294 Variable-speed gear JG GILES 10 July 1973 [20 July 1972] 33924/72 Heading F2D A transmission comprises an input shaft 1 connected to two friction clutches 3, 4, an output shaft 20 connected to a sun-wheel 19 of an epicyclic train, a pump 6 hydraulically connected with a motor 7, two further sunwheels 9, 12 coaxial with the wheel 19, and a planet carrier 15 having a plurality of spindles 16 on each of which is mounted a plurality of planet gears 17, 18, the arrangement being such that the two sun-wheels 9, 12 and the planet carrier are drivable by the input shaft in various combinations through the clutches and the hydraulic pump and motor. Instead of the bevel epicyclic train shown, in which the sunwheels 9, 12 are driven respectively by the clutches 3, 4 through shafts 5, 10 and the planet carrier 15 is driven by the motor 7, a spur epicyclic train, Fig. 4 (not shown), may be employed in which the planet carrier is driven by the shaft 5 and carries a plurality of spindles each of which has three planet wheels meshing respectively with sun-wheels on the output shaft, on the shaft 10, and on a sleeve connected to the motor 7. The pump, whose rotor 11 is driven by the shaft 10, is of the slipper vane type, and its displacement is adjustable manually by a lever 44. The displacement of the motor, also of slipper vane type, is adjustable hydraulically by fluid supplied to chambers 40 by an automatic controller 45 supplied by a pump 2 and subject to control by the lever 44 and input and output speeds. With the pump 6 set at zero displacement and the motor at maximum positive displacement, neutral is obtained with both clutches released, and reverse with the clutch 4 engaged. A low range is operative with the clutch 3 engaged, the motor set at maximum positive displacement, and the pump displacement varied manually between a quarter negative and maximum positive. A drive range is operative with the clutch 3 engaged, the pump set at maximum positive displacement and the motor displacement varied automatically between a quarter negative and maximum positive. For direct drive both clutches 3, 4 are engaged and both the pump and motor are set at zero displacement.