HYDRAULIC AID FOR THE ESTABLISHMENT OF A CONSTITUENT CLIMATE ACTIVITY IN A STEEL-FREE CHANGE GROUP

摘要

In an emergency hydraulic control, in which in an open hydraulic circuit for supplying the various piston chambers of the secondary and primary axial adjusters, at least one throttle valve is disposed. For regulating the primary and secondary pressure, a primary and secondary valve are used, respectively. Each valve is triggered in turn via a respective electromagnetically actuated pilot control valve in the pilot control valve that opens in emergency operation; the pilot control valves are connected to the outlet of the secondary valve, among others, via orifice valves. The pressure fluid pressure in the primary piston chamber is additionally limited by a pressure limiting valve. The outlet of this pressure limiting valve is connected via a control line to the control line located between the primary pilot control valve and the primary valve. At the same time, an orifice valve is disposed between the discharge point of the control line, disposed at the outlet of the pressure limiting valve, into the control line arriving from the pilot control valve and the branching point of this control line from the lead line to the primary-side pilot control valve.The emergency hydraulic control makes a constant clamping force ratio possible, even at low pump feed quantities or low engine speeds. As a result, on startup of the vehicle, a gear ratio adjustment to "overdrive" is avoided, and the next time the engine is started a gear ratio adjustment in the direction of "low" is possible.