Patent ID: 6432016
Filing Date: 2002-08-13
Classification: B60T,F16H

Abstract:
A driving device, for driving the wheels of a motor vehicle, an input, an output and two shiftable friction couplings (3, 4) wherein:said friction couplings (3, 4) are closed by spring tension to connect the input to the output and opened by hydraulic pressure supplied to said friction couplings (3, 4) via gear shift valves (13, 14) and appertaining brake and clutch control-pressure lines (19, 20) to disconnect the output from the input; both friction couplings (3, 4) are closed by said spring tension when the pressure drops in the hydraulic system and perform the function of a parking brake, gear shift pistons (15, 16) of said gear shift valves (13, 14) interactingly connected via auxiliary device control lines (11, 12) with an auxiliary release device which has an adjustable accumulator piston (7) and an accumulator cylinder (8) and which, in an unactuated state, contains a pressureless oil content; and upon actuation of said accumulator piston (7), oil contents accumulated in said accumulator cylinder (8) displaces said gear shift pistons (15, 16) in order to connect said auxiliary device control lines (11, 12) with said brake and clutch control-pressure lines (19, 20) so that the oil contents accumulated in said auxiliary release device opens said friction couplings; said accumulator cylinder (8) is connected via a connecting line (21) with a supply tank (22), and said accumulator piston (7) of said auxiliary release device including an accumulator piston projection (31) extending into a connecting line segment (9) of said connecting line (21), and said connecting line (21) includes a narrow point 24 between said connecting line segment (9) and said connecting line (21) and on the transition of said accumulator piston projection (31) to said connecting line (21) which upon actuation of said accumulator piston (7) is traversed in tight manner by a reduced cross section segment (34) of said accumulator piston projection (9) of said accumulator piston (7) to interrupt the connection to said supply tank (22) upon actuation of said accumulator piston (7) of said auxiliary device.