Patent ID: 9002599
Filing Date: 2015-04-07
Classification: F16H

Abstract:
1. A method of controlling a transmission brake of an automated change-speed transmission, of a countershaft design provided with claw clutches, the transmission brake is functionally connected, on an input side thereof to a transmission shaft and is actuated either hydraulically or pneumatically by an inlet valve and an outlet valve, each of the inlet and the outlet valves is a 2/2-way magnetic switching valve, such that, for an upshift from a gear under load to a target gear, when the loaded gear has been disengaged, to synchronize the target gear, first the inlet valve is opened and the outlet valve is closed, then to produce a substantially constant braking torque (M Br ) the inlet valve is closed after having been open for a determinable opening time duration (T VE ), and to reach a synchronous rotational speed, the outlet valve is opened after having been closed for a determinable closing time duration (T VA ), the opening time duration (T VE ) for which the inlet valve is open being determined as a function of a specified characteristic parameter of the synchronization process, the method comprising the steps of: detecting, with sensors, an initial input rotational speed (n determining, with a transmission control unit and from the initial input and the initial output rotational speeds, an input speed gradient (ng determining, with the transmission control unit, a necessary braking gradient (ng determining, with the transmission control unit, a needed brake pressure (p determining, with the transmission control unit, the opening time duration (T calculating the necessary braking gradient (ng where ng