Zahnradfabrik Friedrichshafen, Ag.

Anton Ott

Friedrich J Ehrlinger

Michael Meyerle

Karlmann Hamma

Dietrich Knodler

Hansjorg Dach

Gisbert Lechner

August Winter

Karlheinz Schachmann

Werner Vetter

Arun Chatterjee

Roland Zdansevicius

Werner Boes

Kurt O Venger

Hans-Jurgen Dach

A planet wheel speed change transmission for motor vehicles arrayed in groups with one basic drive and one group drive associated therewith in series, where the basic drive consists of a speed change transmission with fixedly coupled partial drive and a sequence of gear ratios decreasing in principle from first to highest gear, and the group drive is shifted only once during the entire shift sequence and the number of gears in the basic drive is increased by a single gear, with shift clutches, brakes and free-wheel mechanisms for the automatic shifting of at least four forward speeds, where the shifting of the group drive occurs between two of the gears of the basic drive, or where the group drive is speed-reducing and then shifting occurs also ahead of the first gear of the basic drive and the transmission ratio of the group drive, when it is shifted, is created in dependence upon the gear ratios in the adjacent gears of the basic drive.

Planetary shift gear unit

An infinitely variable compound transmission has a tripartite hydrodynamic torque converter having a pump, a turbine member and a guide member relatively rotatable about a common axis. An input pump shaft normally driven by an engine is connected to the pump, a guide shaft is connected to the guide member and coaxial with the pump shaft, and a turbine shaft coaxial with the guide and pump shafts is connected to the turbine member. A brake connected to the turbine shaft is energizable for immobilizing the turbine shaft against rotation. A coupling clutch connected between the turbine shaft and the guide shaft is actuatable for joint rotation of same about the axis. A bypass clutch is actuatable for connecting the pump shaft to one of the members. An infinitely variable belt transmission operatively connected to the guide shaft has an output shaft connectable to a load. In a starting position, only the coupling clutch is actuated with the brake and bypass clutch unactuated for driving the turbine and guide shafts purely hydraulically. In a forward drive position, both the bypass and coupling clutches are actuated with the brake unactuated for positively coupling the guide shaft and the shaft of the one member. In a reverse starting and drive position, the brake is actuated with the clutches both unactuated for reverse driving the guide shaft purely hydraulically.

Infinitely variable compound transmission

A system for controlling the torque to be transmitted by a fluid-operated friction coupling (clutch or brake) in an automatic speed changer comprises a processor which receives readings of the rotary speeds of an input member and an output member to be interengaged by that coupling and calculates the instantaneous relative angular acceleration .alpha.=-d.vertline..DELTA.n.vertline./dt from these data, the value .alpha. being supplied to a comparator. A computer receiving the same readings determines the optimum acceleration and feeds the result to the comparator whose output actuates a governor controlling the fluid pressure supplied to the coupling.

Torque-control system for automatic speed changer shiftable under load

This invention is for a hydrostatic-mechanical transmission system of the power-branching type having a 'neutral' operating mode. An assembly of a hydrostatic transmission including a variable displacement pump and a hydraulic motor is connected to the input shaft of a mechanical transmission. The mechanical transmission has a speed-range selector defining a first low-speed range for the gearing and a second high-speed range for the gearing. Two planetary gear sets in succession are coupled to the transmission such that the transmission ratios of the hydrostatic transmission and the mechanical transmission establish a neutral mode in each speed range a zero output contribution by the mechanical transmission.

Hydromechanical transmission with power branching

A composite transmission with power branching between a hydrostatic transmission and a mechanical summing transmission in which the hydrostatic transmission has a variable displacement unit. The input shaft is connected to the variable displacement unit and to a ring gear on the four-shaft summing transmission of which the ring gear and sun gear are selectively connectible by respective clutches to the constant displacement hydraulic unit. The planet carrier of the summing transmission is connected to the output shaft. The output shaft can also be directly coupled to the input shaft by a clutch and a further planetary can be provided between the fourth shaft of the summing transmission and the output shaft.

Stepless composite hydrostatic-mechanical transmission

A gear-change transmission in which the input shaft is connected to one element of a pair of planetary gear sets together forming a differential distributing the output between two shafts. One element of each of the planetary gear sets is connected to a coupling shaft which can be braked for reversal of the transmission output while another two elements of the planetary gears are coupled together and to one of the output shafts. The remaining element of the second set is connected to the remaining input shaft and a clutch can be energized to block the differential and effectively couple all of these shafts together. The output shafts are selectively coupled to a further shaft through positive gearing upon actuation of switching clutches.

Gear-change transmission with differential

A hydrostatic transmission has an input connected to a prime mover and an output connected through a speed-change transmission to a load. A control element of this transmission is urged in a direction tending to increase the transmission ratio by a control cylinder pressurized from a hydraulic tachometer operated by the transmission input, and is urged in the opposite direction to decrease the ratio by a regulating cylinder connected via a feed line to the hydraulic network interconnecting the pump and motor of the transmission. During speed change the two cylinders are depressurized and the regulating cylinder is isolated from the network.

Control system for hydrostatic transmission

A hydrostatic torque converter has a hydrostatic transmission and a stepped or gear transmission shiftable under load by selective actuation of respective clutches assigned to the gear trains. The variable-displacement pump is controlled hydrostatically to follow the switchover between clutches with the control pressure to the servocontrolling the displacement of the pump being regulated in response to the fluid pressures of the clutches through respective pressure modulation valves. As a consequence, the hydrostatic transmission compensates for the jump resulting from the shifting of the steps of the gear transmission and follows the stepping of the gear transmission outside the forced actuation of the transmission (positive switching overlap of the shifting clutches) in dependence upon the progress of load transfer from the released to the engaged clutch.

Hydrostatic torque converter having a stepped transmission

A drive shaft and a driven shaft are linked through a differential gearing which distributes the applied torque over two coaxial satellite shafts. One of the satellite shafts is directly connected with the driven shaft through a first steplessly variable split-sheave coupling of the Reeves type while the other satellite shaft, which is immobilizable by a brake, is connected through a second such coupling with an intermediate shaft which in turn can be coupled with the driven shaft via a clutch. With both the brake and the clutch released, the system idles; with the clutch operated, the torque transmitted from the drive shaft to the driven shaft varies inversely with the speed ratio of the two synchronized split-sheave couplings whereas actuation of the brake in lieu of the clutch doubles the output speed and halves the transmitted torque. If only unidirectional rotation is to be transmitted, the clutch can be replaced by a one-way coupling which lets the driven shaft rotate freely when the brake is engaged.

Continuously adjustable transmission with two speed ranges

An automotive transmission comprises a plurality of cascaded planetary-gear stages consisting each of a sun gear, a planet carrier and a ring gear. The stages, or some of them, constitute modular units which may be added or eliminated to vary the number of available speed ratios. With four stages and eight selectively operable coupling elements, i.e., four clutches and four brakes, eight forward speeds and six reverse speeds may be realized. The sun gears of three stages are fixed to a common intermediary shaft, connectable to an input shaft by one of the clutches, while the corresponding ring gears are individually immobilizable by respective brakes. Two of the three components of the fourth stage, namely the carrier and the ring gear, are cross-connected with the ring gear and the carrier of the third stage and, like the sun gear of this fourth stage, may be individually linked with the input shaft via other intermediate shafts and associated clutches. The planet carrier of the first stage is fixed to an output shaft while the carrier of the third stage is rigid with the ring gear of the second stage; the carrier of the second stage is fixedly connected with either the ring gear or the carrier of the first stage.

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Tettnang, Germany

Anton Ott