GB1381689A - Hydromechanical transmission - Google Patents

Abstract

1381689 Variable-speed gear ORSHANSKY TRANSMISSION CORP 4 June 1973 [5 June 1972] 26609/73 Addition to 1364962 Heading F2D The hydromechanical transmission is functionally the same as that of Fig. 1, of the parent Specification 1,364,962, and is analysed by the same speed-relation diagram shown in Fig. 3, therein, but the embodiment differs in that its torque capacity is increased by a fixed ratio planetary reduction gear 303 between the input shaft 20 and the two planetary trains 311, 330; and also in that the first planetary train 311 is of the intermeshed planet type with two suns 316, 321 and no ring gear. The first sun 316 of the first train 311 and planet carrier 333 of the second 330 are alternatively connected to final output 320 by clutches 318, 335 respectively. The planetary reduction gear 303 has a permanently fixed ring gear 306, an output carrier 304, connected through a sleeve shaft 309 to the carrier 310 of the first planet gear 311 and ring 331 of the second 330, and a sun 302 connected respectively to input 20 and to the first train sun 316 by clutches 300, 336. The connected suns 321,332 of the two trains 311, 330 are mounted on a sleeve shaft 322 connected through a meshing pair 323, 324 to a fixed stroke hydraulic unit 46, fed by a variable stroke unit 24 driven at constant speed by the input shaft 20 through a meshing pair 21, 22. Operation, which is explained in Fig. 3, of the parent Specification, is as follows. A starting all hydraulic phase is produced by engaging clutches 336, 335, the former establishing a locked ratio in the two planetary trains 311, 330, and hence between the fixed stroke unit 46, together with the common suns 321, 332, and the second carrier 333 clutched to output 320 at 335. At the maximum position of the hydraulic gear the clutch 300 synchronizes, and range I in the hydromechanical phase is introduced by releasing clutch 336 and engaging 300 to provide an invariable geared reduced drive to the carrier 310. The hydraulic gear is cycled in the opposite direction, causing the suns 321, 332 to decrease in speed as the sun 316 increases to synchronism at the end of range I, whereupon hydromechanical range II is introduced by releasing clutch 335 and engaging 318 followed by re-cycling of the hydraulic gear to the maximum, at which point a final lock-up can be provided by engaging synchronously the clutch 336.