GB1364962A - Power transmission - Google Patents

Abstract

1364962 Variable-speed gear ORSHANKSKY TRANSMISSION CORP 16 June 1972 [21 June 1971] 28280/72 Heading F2D A split-torque hydro-mechanical variablespeed gear on a motor vehicle or machine tool, providing two; three or four stages of operation during each of which a hydrostatic variable drive in one branch is cycled through its full range to permit selective synchronous clutching of the succeeding stage, comprises a planetary assembly having an input member, e.g. first carrier 30; two coaxial output members, e.g. first ring gear 34 and second carrier 37; and a common reaction member, e.g. first and second suns 33, 41; and speed varying means such as a variablestroke hydraulic pump 24 and fixed-stroke motor 46 for causing the speed of one planetary output member 34 or 37 to increase whilst that of the other simultaneously decreases whereby the planetary output members can be clutched synchronously to a final output shaft 50 to provide continuous ratio variation as the variable gear is cycled through its range in both directions. In a two-range form, shown in Fig. 1, the common reaction suns 33, 41 are geared at 43, 44 to the motor 46; the connected first carrier 30 and second ring 36 secured to a wheel 28 meshing a wheel 34 which can be clutched at 25 to a shaft 23 of the pump 24, driven constantly by a main input shaft 20; and the two output members, first ring 34 and second carrier 37 are selectively clutchable at 54, 52 respectively to a main output shaft 50. A wholly hydrostatic starting phase, followed by two hydro-mechanical stages are provided as follows. For the starting phase, forward or reverse, the clutch 25 is released and a clutch 49 engaged to provide hydrostatic drive in the appropriate direction depending on the direction of adjustment of the pump stroke, from the motor 46 through wheels 47, 48, 26, 28 to the input carrier 30, and also through meshing wheels 44, 43 to the common suns 33, 41, drive issuing to output 50 through the clutch 52. At the end of hydrostatic range stage 1 is entered by releasing the clutch 49 and engaging 25 synchronously so that the first carrier 30 is now driven mechanically from the input-driven pump shaft 23, whilst the common suns 33, 41 are driven hydraulically by the motor 46 through the meshing gears 44, 43. The clutch 52 is engaged for the first stage, and the variable gear cycled through its range after the clutch 52 can be released and 54 engaged synchronously for the second stage, during which the hydraulic gear is cycled back through its range. Fig. 5, not shown, provides an additional output train with a reaction brake for a third stage, whilst Fig. 8, not shown, has two such output trains for four stages.