Abstract: A transmission, in particular for a motor vehicle, includes an infinitely variable V-belt transmission with a primary pulley having a primary shaft and a secondary pulley, each having two conical sheaves, a primary and a secondary hydraulic operating cylinder, respectively, for the axial displacement of at least one of the conical sheaves of each pulley, a hydraulic control valve for the control of the transmission ratio, the valve having a housing and an internal valve spool that can be displaced from an end position in which the valve spool rests against a stop and the valve housing having ports openable for the discharge of fluid from the primary operating cylinder and/or the supply of fluid to the secondary operating cylinder, to a center position where ports are substantially closed, so that virtually no supply of fluid to and discharge of fluid from at least one of the operating cylinders can take place, a hydrodynamic transmission unit having a rotary output member connected to said primary shaft and a

Abstract: A transmission mechanism in particular for automobiles with a front wheel drive comprises a planetary forward-reverse gear set and a continuously variable pulley drive that is drivingly connected to a differential gearing. A forward friction disk clutch provided for obtaining a forward driving direction of the transmission mechanism may be selectively operated by a servo piston that is fixedly connected in an axially stationary manner to the adjusting piston of a hydraulic adjusting means provided for the selective adjustment of the movable sheave of a primary pulley of said pulley drive whereby the mutual arrangement is chosen in such a manner that the adjusting cylinder being fixedly connected to this movable sheave at least partly surrounds the servo piston. By this particular arrangement the axial dimension of the entire transmission mechanism may be reduced without the requirement of a separate starting clutch for the entire clutch assembly.

Abstract: The invention relates to a transmission for vehicles, in particular for automobiles with front wheel drive, which have a driving motor mounted transverse to the longitudinal direction of the vehicle, whose drive shaft drives the primary shaft of an infinitely variable belt drive having a secondary shaft driven in the same direction of rotation by means of a drive belt and mounted coaxially with the drive pinion of a differential gear provided with output shafts. A reversing and reduction gearing, designed as a planetary gearset, is mounted coaxially with the secondary shaft of the belt drive and connected through its input member to the secondary shaft and through its output member to the drive pinion of the differential gearing, while its reactive section is fixed to the casing. As a result, a very compact transmission unit is achieved, having in forward drive position an output rotation in the same direction as the input rotation.

Abstract: Apparatus for controlling the transmission ratio of an infinitely variable motor vehicle transmission of the type including a belt and two pulleys each having conical discs which are hydraulically movable toward and away from each other, the apparatus including a hydraulic valve having an axially movable internal pilot slide for supplying and exhausting hydraulic fluid to the movable pulley discs to effect movement thereof, a first device responsive to actual engine speed for urging the slide in a first direction, a second device responsive to desired engine speed for applying an urging force on the slide in a second, opposite direction, and a third device for limiting the resulting urging force on the slide in the second direction, the third means being responsive to the transmission ratio.

Abstract: In apparatus for controlling the transmission ratio of an infinitely variable V-belt transmission having variable pitch input and output pulleys operable by hydraulic cylinders, each pulley being formed of a pair of conical discs, at least one of which is axially movable relative to the other disc of that pair and the input pulley being driven by a power source: a hydraulic control valve for operating the cylinders, the valve having an internal axially movable spool; a device responsive to the speed of the input pulley for urging the spool in one direction; a compression spring urging the spool in an opposite direction, the spring being loaded through an intermediate connecting assembly by an external loading device; and a regulating device connected to the intermediate connecting assembly, the regulating device being responsive to an operating variable of the transmission.

Abstract: The invention concerns the control of an infinitely variable transmission, provided with an endless transmission member running over a primary and a secondary V-shaped pulley, one conical disc of each pulley being affixed to a shaft, respectively the primary and the secondary shaft, and the other conical disc being controlled in axial direction by a hydraulic cylinder-piston unit, respectively the primary and the secondary cylinder-piston unit, the tension in the endless transmission member being controlled by means of a first control valve and that the transmission ratio is controlled by regulating fluid supply and discharge from and to the other cylinder by means of a second control valve.

Abstract: The invention concerns a stepless variable belt transmission with pulleys which comprise two axially movable conical halves. The displacement of the pulley halves is effected by hydraulic piston-cylinder units rotating along with the pulleys. At least one hydraulic piston-cylinder unit is provided with a compensation chamber wherein a pressure is built up as a function of the speed. According to the invention the compensation chamber communicates with a closable opening with the cylinder chamber by means of which the pulley halves are relatively moved.