Abstract: The invention relates to a hydraulic system for actuating a continuously variable belt-driven conical-pulley transmission having two conical pulleys encircled by an endless torque-transmitting means, each of which comprises two conical disks, one of which is axially movable depending on the pressure in an associated pressing chamber, and having a torque sensor which includes a torque sensing chamber that is connected to a hydraulic energy source and is linked with the pressing chambers. The invention is distinguished by the fact that the pressing chambers are connected via a first hydraulic resistance element to the torque sensing chamber, and via a second hydraulic resistance element to an additional pressure chamber, in which a lower pressure prevails than in the pressing chambers and/or the torque sensing chamber.

Abstract: A hydraulic supply system for a motor vehicle includes an internal combustion engine, a pump driven by the internal combustion engine, and a hydraulically operated component that is driven by hydraulic fluid transported by the pump. An electric motor is provided to drive the pump when the internal combustion engine is not running.

Abstract: A hydraulic supply system for a hydraulically actuated automatic transmission, in particular for a belt-driven conical-pulley transmission. The system includes a primary pump driven by a primary drive system to provide pressure in a supply line connected to a regulating valve. The supply line is connected through a pilot valve to a control line in which a control valve is situated, with which the pressure that determines the setting of a transmission ratio adjusting valve is set. An auxiliary pump driven by an auxiliary drive system that is separate from the primary drive system includes an outlet line connected to the control line through a first valve that opens in the direction of the control line, and is connected to the supply line through a second valve that opens in the direction of the supply line.

Abstract: A hydraulic system for controlling a belt-driven conical-pulley transmission. A pump draws a working medium from a working medium tank or through a cooler return valve from a cooler return line. The cooler return valve is a minimum pressure valve that holds closed a connection between the cooler return line and a pump inlet line through the cooler return valve, as long as the pressure in the cooler return line remains below a specified minimum pressure. The cooler return valve also opens the connection between the cooler return line and the pump inlet line through the cooler return valve as soon as the specified minimum pressure in the cooler return line is exceeded.

Abstract: A hydraulic system for an automatic transmission operatively connected to an internal combustion engine that is operable in a start-stop mode. The hydraulic system includes a hydraulic energy source to supply the hydraulic system with hydraulic energy, the hydraulic energy source including at least one electrically driven hydraulic pump to supply the hydraulic system with hydraulic energy during a stopping phase of the internal combustion engine. To achieve a reduction in fuel consumption and CO2 emissions, provision is included to enable the electrically driven hydraulic pump to be switched on in addition to a mechanically driven hydraulic pump, as needed during an operating phase of the internal combustion engine.

Abstract: A hydraulic system for controlling a belt-driven conical-pulley transmission of a motor vehicle having a variably adjustable transmission ratio, and having an electrical actuation system for overall control of the hydraulic system, and a hydraulic parking lock-release system to control a parking lock. In order to provide an improved hydraulic system, the parking lock includes a self-retention system in the event of an electrical power failure.