Valve arrangement for a hydraulic transmission circuit

Abstract

A valve arrangement for a hydraulic transmission circuit, in particular for a change-under-load transmission with a clutch valve arrangement for controlling at least one clutch and/or start-up clutch with the aid of a pressure-regulating valve whose normal position can be influenced mechanically by a clutch pedal. The pressure-measuring area of the pressureregulating valve is connected to a control valve whose piston, acted on by the clutch pedal, can be brought, against the force of a spring placed between the pressure-regulating valve and the control valve, first of all out of a position that relieves the pressure-measuring area of load into a floating position in which the pressure-measuring area is connected to the pressure-regulating valve outlet. Then, and after traversing a certain path, it can be brought into contact with the valve body of the pressure-regulating valve. Here the valve body is slaved and is kept in a position in which the pressure-regulating valve outlet is connected by as large a cross-section as possible to the tank connection. The pressure-regulating valve includes a position and a control area which acts in opposition to a force on the pressure-measuring area. A second spring acts on the control area without utilizing a pressure tight chamber. The arrangement can be simply supplemented by a start safety valve that is connected in parallel to the pressure-regulating valve and to the safety valve and that can be brought, exclusively by mechanical action when moving the piston, acted on by the clutch pedal, out of an initial position blocking a neutral shift position valve in the neutral position into an unblocking position in which the neutral shift position valve can be unblocked.

Dependencies are inferred from the claim text.