GB834694A - Variable speed transmission system especially for vehicles - Google Patents

Abstract

834,694. Change-speed gear; slip couplings. VOITH G.m.b.H., J. M. July 8, 1957 [July 7, 1956], No. 21616/57. Class 80 (2). In a change-speed gear 3 for a motor vehicle wherein speed changes under load are effected solely by changing engagement of ratio selecting mechanical clutches 7, 8 or brakes, without operation of a main clutch, shock loading of the transmission due to rapid synchronizing by the ratio clutches during gear shift is avoided by the provision in a separate casing between the motor 1 and change-speed input shaft 3<SP>1</SP> of a permanently engaged friction slip coupling, the torque capacity of which is limited to 1.2 to 1.3 times the maximum motor torque. During gear shift this coupling slips and effects synchronization slowly. In Fig. 1, the countershaft gear provides a direct and reduced drive by the two clutches 7, 8. In Fig. 2, the gear provides a hydromechanical torque-split drive by a power dividing gear comprising an input planet carrier 103<SP>1</SP>, and two bevel side wheels 130, one connected to output 104 through a hydrodynamic torque converter 132 and a oneway clutch 136, the other connected directly to the output. Application of a brake 108 to the right-hand bevel upshifts the gear to a wholly mechanical overdrive. A further planetary change-speed stage 141 may be added. Figs. 3-5 (not shown), are curves of engine speed against output speed, and input speed and torque against time during shift. The slip coupling, Fig. 6, comprises a driven frictionfaced disc 256 clamped against a driving flywheel 251 by a pressure plate 255 loaded by springs 254, adjustably compressed by screws 252, accessible for adjustment through a removable cover 267. A resilient coupling ring 260 may be arranged on the input or output side of the coupling, which latter may operate dry or in oil.