Abstract: A hydraulic supply system for a hydraulically-operated automatic transmission includes a primary pump that is driven by an internal combustion engine of a vehicle. An electrically-driven auxiliary pump is provided to supply the system with hydraulic pressure when the primary pump is off or to supplement the primary pump when the primary pump does not deliver sufficient pressure. A discharge line from the auxiliary pump is connected to a control line of the hydraulic supply system and to the hydraulic system supply line under system pressure. Check valves are provided in the respective lines from the auxiliary pump. An additional check valve is provided in a line that extends from the control line to a torque sensing chamber of the automatic transmission.

Abstract: A hydraulic system for actuating a clutch and/or a variable speed drive unit of a belt-driven conical-pulley transmission of a vehicle, such as a commercial vehicle, and having a variable transmission ratio and a torque sensor. The hydraulic system includes at least one hydraulic energy source. A selector and check valve is provided for supplying additional components besides the torque sensor and is connected between the hydraulic energy source, the additional components, and the torque sensor in such a way that the torque sensor includes priority in being supplied with hydraulic medium.

Abstract: A hydraulic supply system for a hydraulically-operated automatic transmission includes a primary pump that is driven by an internal combustion engine of a vehicle. An electrically-driven auxiliary pump is provided to supply the system with hydraulic pressure when the primary pump is off or to supplement the primary pump when the primary pump does not deliver sufficient pressure. A discharge line from the auxiliary pump is connected to a control line of the hydraulic supply system and to the hydraulic system supply line under system pressure. Check valves are provided in the respective lines from the auxiliary pump. An additional check valve is provided in a line that extends from the control line to a torque sensing chamber of the automatic transmission.

Abstract: A valve having a housing and including a rotatable rotary spool that includes a conducting chamber. A first inlet communicates with the conducting chamber and with a plurality of outlets that are selectively individually connected with the conducting chamber as a function of the rotational position of the rotary spool within the valve housing. The conducting chamber communicates with a first pressure chamber through a first check valve carried by the rotary spool. A second check valve carried by the rotary spool provides communication between the first pressure chamber and a second pressure chamber that surrounds the rotary spool.

Abstract: A hydraulic system for actuating a clutch and/or a variable speed drive unit of a belt-driven conical-pulley transmission of a vehicle, such as a commercial vehicle, and having a variable transmission ratio and a torque sensor. The hydraulic system includes at least one hydraulic energy source. A selector and check valve is provided for supplying additional components besides the torque sensor and is connected between the hydraulic energy source, the additional components, and the torque sensor in such a way that the torque sensor includes priority in being supplied with hydraulic medium.