GB882847A - Improvements relating to variable speed gears - Google Patents

Abstract

882,847. VariableÀspeed gear. ZAHNRADFABRIK FRIEDRICHSHAFEN A.G. April 23, 1959 [April 24, 1958; May 3, 1958], No. 13946/59. Class 80 (2). In a hydromechanical change-speed gear with coaxial shafts, two brakes or clutches are provided for each ratio in forward drive, one being connected directly, and the other through a freewheel, to the associated shaft, the freewheel being so arranged that the shaft is locked against reverse rotation and on shift into a higher ratio overruns the other brake or clutch. The two-speed gear shown in Fig. 2 comprises aligned input and output shafts 101, 102, a single-circuit torque converter 103 with a bridging clutch 113 for direct drive, planetary gear units 145, 146, forward drive brakes 109, 110, the latter having an associated freewheel clutch 127, and a reverse brake 111. At starting clutch 113 is free and brakes 109, 110 engaged, and gear is engaged by engaging clutch 113 and releasing brake 109, the freewheel 127 releasing brake 110. Fig. 4 shows a threespeed forward drive arrangement with an associated planetary gear unit 462 and brakes 466, 468 for doubling the number of speeds. In a further embodiment, Fig. 6, the brakes for engaging forward speed ratios are replaced by clutches 609, 610, 611 and the gearing is of the non-planetary type, the pinions 620, 621, 622 being carried by a layshaft 626. Such an arrangement may incorporate a reverse-drive clutch, Fig. 7 (not shown), or an axially-movable rod for effecting engagement of the gear train pinions. Fig. 8 (not shown).