J. M. Voith Gmbh

Voith Getriebe Kg

Klaus Brosius

Berthold Herrmann

Tillmann Korner

Hans Lindenthal

Franz X Zaunberger

Helmut Muller

Konrad Langenbeck

Olaf Spitzer

Rudolf Fetzer

With a differential gearing having a spur gear construction, the compensating gears (31a, 31b) are installed in meshing pairs and are tightly enclosed by a housing (14) so that with meshing spur gears (22, 23) they can act as toothed pumps with pressure zones, with a locking moment being produced between the two driven shafts (2,3). A substantial increase in the locking moment is achieved in that the compensating gears constructed as pinions are disposed in a determined sequence on the circumference of the spur gears and also comprise along their face width partitions (32) which prevent a reduction in pressure along the toothing. As a result with an equal number of pinion pairs there is produced a number of pressure zones which is more than double and consequently there is an increase in the locking moment developed.

Self-locking hydrostatic differential gearing

A differential gearing, in which the torque introduced via an input shaft is distributed equally to two driven shafts, is constructed as a spur gear differential and has a pinion arrangement as the locking mechanism in which the pinions and spur gears work as geared pumps. The pump moment is directly the locking moment, with the hydrostatic pressure developed being reduced by precisely dimensioned clearances without any further control devices being required. A special arrangement of the pinions in a housing guarantees an equal locking moment in both directions of rotation.

Self-locking differential gearing

For the reduction of capacity losses and heating in hydrodynamic working circuits, especially retarders, caused by undesired air circulation in emptied condition, it is suggested to introduce a certain quantity of a blocking medium into the working chamber. This blocking medium may be operating fluid, air, or a mixture of both, and can be introduced radially from the inside, from the outside, or from the center. It forms a blocking film by rotation of the bladed rotor wheel, which substantially prevents the circulation of air from one bladed wheel to the other.

Hydrodynamic working circuit with device for reducing air circulation

The invention relates to a hydrodynamic retarder having two independent operating circuits. Opposite a double rotor on the one hand is a stator fixed to a housing, and the rows of vanes concerned are inclined. The other half of the rotor forms with a rotatable stator and a second operating circuit having rows of blades equally effective in both rotational directions. The stator of this second operating circuit can be coupled via a gear unit and a coupling device to the retarder shaft. The gear unit drives the stator in a direction opposite to the direction of rotation of the rotor and with step-up transmission. When braking from a high travelling speed, only the first operating circuit is effective, the stator of the second operating circuit is released by the retarder shaft and freely rotates as well without any braking action. As the speed drops, the coupling device is actuated and the stator of the second operating circuit is driven in the opposite direction, during which the second operating circuit is temporarily emptied. The advantage of this arrangement is high braking force at high speeds of travel, associated with high braking force in the low speed range right down to approx. zero and in both directions of travel, also the retarder does not need to be attached to the gear shift and does not need to feed power in by a driving engine.

Hydrodynamic retarder

The disclosure concerns a hydrodynamic control coupling with a primary drive vane wheel and a secondary driven vane wheel which together define a toroidal working chamber. Each vane wheel carries an array of vanes on its interior which extend toward the vanes of the other vane wheel. The vanes of the vane wheels are inclinded with respect to the axis of the coupling, yet each is oriented parallel to a respective radius of the coupling. Furthermore, the vanes on each of the vane wheels are inclined to extend toward the vanes on the other wheel. There is a working fluid inlet to the working chamber. A working fluid outlet from the working chamber is through the secondary, driven vane wheel and is via a plurality of bores extending tangentially toward the axis of the coupling. An overflow valve communicates with the outlet from the working chamber. Upon the rotary speed of the primary vane wheel increasing rapidly, the overflow valve reacts by opening more widely, reducing the filling level in the coupling. A temperature sensor may be connected with the overflow valve for operating the overflow valve so it is dependent upon the temperature sensed by the sensor. The temperature sensor may be in the engine cooling circuit of an engine, and the coupling may drive a cooling fan for that circuit. The valve will control the torque of the coupling for desired cooling rotation of the fan, depending upon the sensed temperature of the engine cooling circuit.

Hydrodynamic control coupling

The invention concerns a hydrodynamic torque transfer unit, particularly in the form of a hydrodynamic brake. Flow to the inlet of the working chamber of the transfer unit is controlled by an inlet valve movable between a closed, partially open and fully open position. A first piston moves the valve between its positions. A change over device cooperates with the first piston. The change over device includes a second piston. A first pressure chamber is defined between the first and second pistons. A second pressure chamber is defined behind the second piston. Initially, the first pressure chamber is pressurized, driving the first piston and thus the inlet valve to the fully open position. The second piston is moved by pressurization of the second pressure chamber to cut off pressure to the first pressure chamber and to instead cause communication between the first pressure chamber and the working chamber. Typically, the working chamber is at reduced pressure which thereby permits depressurization of the first pressure chamber. A spring then returns the inlet valve back toward the intermediate open position. The second piston has been shifted by pressurization of the second pressure chamber to prevent the first piston and thus the inlet valve from returning to the fully closed position, and the inlet valve therefore remains at the intermediate open position. There may be an outlet control which also regulates the outlet flow from the working chamber. The first pressure chamber may communicate with the working chamber through the outlet control.

Hydrodynamic torque-transfer unit, especially a hydrodynamic brake

A hydrodynamic brake is disclosed of a kind comprising a rotor bucket wheel and a stator bucket wheel in a housing and defining a torus-shaped working chamber and defining between them a bucket wheel gap. An outlet duct surrounds the perimeter of the rotor bucket wheel. A plurality of baffle type flow obstructions are provided about the periphery of the bucket wheel gap, and are movable into the bucket wheel gap and when the brake is not engaged. A small gap between the radially outermost part of the rotor bucket wheel and the housing is continuous with the outlet duct. A second duct connects the outlet duct and the space in which the baffle type flow obstructions are accommodated, thereby preventing unwanted movement of the flow obstructions into the bucket wheel gap while the brake is engaged.

Hydrodynamic brakes

The disclosure contains a hydrodynamic torque transmitting unit particularly for a hydrodynamic brake. A working chamber that is filled with working fluid contains a stator and a rotor. An inlet valve controls inlet of fluid to the working chamber. A piston connected with the inlet valve selectively closes the valve. The piston initially opens the inlet valve fully for a surge of working fluid into the working chamber. In a stage I condition, valving and pressure chambers associated with the piston returns the inlet valve to an intermediate position reducing the inflow of working fluid into the working chamber after the initial surge. In a stage II condition, the pressure chambers remain continuously pressurized for holding the inlet valve in the condition of maximum supply of working fluid to the working chamber. Various piston arrays are described in different embodiments. In the various embodiments, different piston arrangements, utilizing two pressure chambers operating selectively together or in opposition to each other, determine the various positions of the piston which moves the inlet valve. Appropriate valving and switches direct the pressure supply to the different pressure chambers at different times for moving the piston as needed to move the inlet valve. The switching is done either through a time delay arrangement and/or through a sensor directly connected with the working chamber for sensing the pressure therein.

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Heidenheim, Germany

Klaus Brosius