Abstract: A method for regulating a belt variator type transmission unit for motor vehicles, and which includes a belt variator, a reversing unit and a hydraulically controlled engine drive coupling that controls the reversing unit to provide forward and reverse drive connection between the engine and variator. The drive coupling comprises a forward coupling and a reverse coupling including fluid driven clutches which may be operated via a pressure regulating unit that provides an adjustable clutch actuating pressure. The clutch actuating pressure is hydraulically regulated both as a function of engine Pitot pressure which is representative of the engine speed, and as a function of a regulated pressure which is set by an electronically controlled valve.

Abstract: Method for lubricating and/or cooling a transmission unit, in particular a transmission unit of the type which makes use of a continuously variable transmission (2) with pulleys (5-6) and an endless transmission element (7) provided in between, at least one hydraulic cylinder/piston unit (13) with a pressure chamber (15) which cooperates with the continuously variable transmission (2), and a pressure compensation chamber (23) cooperating with the above-mentioned pressure chamber (15), wherein at least part of the hydraulic medium coming out of the pressure compensation chamber (23) is guided back via a number of parts of the transmission unit (1) to be lubricated and/or cooled, so as to provide for the lubrication and/or cooling of these parts.

Abstract: Transmission unit for motor vehicles of the type which is provided with a continuously variable transmission (3), a reversing unit (2) and a number of clutches (16-18) to engage the reversing unit (2) in one or the other sense of rotation. At least one of these clutches (16-18) is controlled by a hydraulic pressure unit (25), with a piston (27) which can be moved in a cylinder (28), whereby the seal between the piston (27) and the cylinder (28) is an elastic sealing ring (32), The piston (27) is provided with at least one passage to let hydraulic medium escape under the influence of the centrifugal force, whereby the at least one passage (43) is located in the above-mentioned sealing ring (32).

Abstract: Transmission unit for motor vehicles, consisting of a continuously variable transmission (2); at least one hydraulic cylinder/piston unit (13) with a pressure cheer (15) co-operating with the continuously variable transmission (2); a pressure compensation chamber (22) co-operating with the above-mentioned pressure cheer (15); and a passage connection (26) connecting the pressure compensation chamber (22) with the pressure chamber (15) , wherein a pressure-sensitive passage control member (28) is provided in the above-mentioned passage connection (26).