Volkswagenwerk Aktiengesellschaft

Volkswagen Ag

Gerd Oberpichler

Ernst-August Honig

Heinz Dorpmund

Dieter Schmidt

Ferdinand Piech

Lothar Kaspar

Manfred Kalversberg

Gottfried Hagemann

In a hydrodynamic-mechanical transmission for motor vehicles, consisting of a torque converter followed by a planetary gear with hydraulically actuable shift mechanism associated with the several transmission elements to select the various speeds, the planetary gear including a first sun gear connectable by way of a first clutch to the turbine rotor of the torque converter, a second sun gear connectable by way of a second clutch to the turbine rotor, a planetary mount connectable by way of a third clutch, bypassing the torque converter, directly to the engine drive shaft, on which mount first and second planet gears in engagement with each other and with the sun gears are mounted, and an internal gear constituting the drive output and in engagement with second planet gears meshing with the second sun gear, the possibility exists of reaching the third, direct speed either by purely hydrodynamic means including the torque converter by engaging the first and second clutches, by purely mechanical means bypassing the torque converter by engaging all three clutches, or in branched power trains by engaging the first or the second clutch and the third clutch. To achieve smooth transitions to and from third speed, when shifting up automatically from second to third speed, first the hydrodynamic train with first and second clutches engaged is to be selectable, and then the mechanical train by additionally engaging the third clutch. Then, shortly before shifting to fourth speed, the branched power train is to be selectable briefly by disengaging the first or the second clutch.

Shifting method for hydrodynamic-mechanical transmission

A pneumatic control system is disclosed for an automatic transmission for a vehicle of the type having a mechanical planetary gear train with hydraulically actuatable gear elements. A manual control valve dependent upon the position of the transmission gear select lever conveys a pressure medium, for actuating a gear shift element associated with the selected gear when said lever is moved to one of the forward gears of the transmission, through a pressure medium line connected between the manual control valve and the gear shift element. The control system comprises a main control valve dependent upon the position of the accelerator pedal for exhausting the fluid in the gear shift element for disengaging the gear shift element in operating states of the vehicle at least when the vehicle is stationary, the transmission gear select lever is moved to the drive position (D), and the accelerator pedal is released.

Pneumatic control system for an automatic vehicle transmission

An automatic transmission for a motor vehicle of the type having a mechanical planetary gear train with hydraulically actuatable gear shift elements has a gear select lever having a plurality of selectable forward drive positions, including automatic forward drive (D). A manual control valve, responsive to the position of the select lever, supplies a first pressurized hydraulic fluid to a selected gear shift element, e.g. a forward gear clutch, when the lever is in one of said forward drive positions. A control system which selectively interrupts the supply of fluid to the selected element comprises a main control valve, and a second fluid pressure acting on the main control valve to connect the supply of the first fluid to the gear shift element for engaging the element. A purging control valve vents the second fluid pressure supplied to the main control valve when the accelerator pedal is released, to discontinue the first fluid supply and exhaust the fluid from the gear shift element to disengage the element. A brake pedal position dependent control acts on the main control valve for permitting the gear shift element to disengage only when the brake pedal is depressed.

Control system for an automatic vehicle transmission

A hydraulic control device for an automatic vehicle transmission includes a main pressure control valve for delivering an engine load-dependent main output pressure for operating actuating components of the vehicle transmission and a pressure-limiting valve for delivering an engine load-dependent, upwardly limited control pressure. The pressure-limiting valve includes a control piston exposed to the control pressure and to the force of a spring opposing the control pressure. The device further has an additional control valve for applying to the main pressure control valve an output pressure which is a function of a vehicle speed-dependent pressure and the control pressure and which is modulated by the control pressure and a higher main input pressure.

Hydraulic control for an automatic vehicle transmission

A motor vehicle hydrodynamic transmission is provided with a torque converter and a planetary gear train. In order to provide a compact transmission arrangement, the stator of the torque converter is connected to the planetary gear carrier by means of a freewheel, and the planetary gear carrier is connected to the housing by another freewheel. The planetary gear is also connected to the housing by a controllable brake. The brake and freewheel connecting the carrier to the housing are arranged radially outward from the planetary gear train. The second sun gear of the planetary gear train and the second brake, which acts on the second sun gear, are arranged on the side of the planetary gear train facing away from the torque converter. The output of the planetary gear train is a pinion, which is connected to the inertial gear and located between the torque converter and the planetary gear train.

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Brunswick, Germany

Gerd Oberpichler