Driving device
AssigneeZF Friedrichshafen AG
InventorEduard Heilig
Life of this patent
Estimating the term…
Abstract
The driving device comprises a hydraulically shiftable friction coupling and a friction brake by means of which an input can be connected to a gear and which perform the function of a parking brake wherein an auxiliary release device comprising an adjustable accumulator piston and gear shift pistons interacting therewith separate friction coupling and friction brake thus interrupting the drive train; the accumulator cylinder of the auxiliary release device is connected to a supply tank via a connecting line and is provide with a blocking device which cuts off the connection to the supply tank when the auxiliary release device is actuated.
Claims10
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.
Dependencies are inferred from the claim text.