GB784119A - Improvements in or relating to vehicle driving arrangements - Google Patents

Abstract

784,119. Change-speed differential gearing. ROLLS ROYCE, Ltd. Jan. 20, 1954 [Oct. 28, 1952], No. 27121/52. Class 80 (2). A driving arrangement for track-laying vehicles comprises a hydro-kinetic unit (e.g. a fluid-coupling 14) interconnecting a power input shaft 11 and a cross-drive shaft 25, the torque being transmitted partly by the coupling 14 and partly by a hollow primary cross-shaft 13 on which the impeller 15 is mounted. This construction is compact and light and allows spur gears 23, 24 to be secured to either end of a further hollow shaft 22, which is inside the primary shaft 13 and driven through an epicyclic gear 16, 19, 20. The cross-drive shaft is driven by one of the spur gears 23, 24 through one of three epicyclic gears 31, 39, 47, providing four forward and one reverse speeds, brakes 33, 41, 48 and clutches 34, 42 providing changespeed means. The track driving sprockets (not shown) are secured to shafts 10 which are driven by the cross-drive shaft 25 through epicyclic gears 50 and by a differential gear, the cage 54 of which is formed integrally with the hollow shaft 22. The drive through the differential gear is negative and normally takes speed off the main drive, so that by applying a brake 66 to stop the shaft 25, a very low reverse speed is obtained. Alternatively the speeds may be arranged to add. Normally equal torque is transmitted to the shafts 10 and track sprockets, but brakes 65 vary this to provide steering control. In one modification, Fig. 2, a torque converter 70 replaces the fluid coupling. This converter 70 comprises a pump element 71 rotating with the primary cross-shaft 13, a turbine element 72 driving in part the spur gear 23 through epicyclic gearing and a two-part stator section 74, 75. Each part of this stator section drives a sleeve 76 through a free-wheel device 77 or 78 when a brake 79 is released and a clutch 80 engaged to allow the converter to function as a fluid coupling, for the higher reduction ratios. By engaging a clutch 81, the pump and turbine elements are locked to give a direct drive. In a second modification, Fig. 3, an additional epicyclic gear 92 on the cross-drive shaft 25 provides a fifth forward speed. Specification 607,120 is referred to.