DE29700605U1 - Gear unit and hydrodynamic unit - Google Patents

Description

G 05529 / 297 00 605.3 / Voith Turbo GmblJ & Cp* KGJ "purejl^^^/qwijq^j / y* June 1997

Gear unit and hydrodynamic unit

The invention relates to a transmission unit, in particular with the features of the preamble of claim 1; furthermore, a hydrodynamic unit.

Gear units that include a mechanical gear part and a hydraulic, preferably a hydrodynamic gear part are known in a variety of designs. The hydrodynamic gear part can be designed as a hydrodynamic clutch or as a hydrodynamic converter. These units, also known as fluid gears, include at least one pump wheel and one turbine wheel, which together form at least one toroidal working space. This can be filled with operating fluid.

The liquid is accelerated via the pump wheel and decelerated again in the turbine. The torque generated is therefore essentially caused by mass forces that result from the change in speed of the liquid flow. The power transmitted is then the product of the change in swirl of the mass flow and the angular velocity. In addition to the pump and turbine wheels, a hydrodynamic converter also consists of a reaction element, which is called a stator. This stator is able to absorb a moment. Since the sum of the moments in the circuit must be zero, the turbine moment can be greater, equal or smaller than the pump moment depending on the size and direction of rotation of the stator moment. This allows the speed range to be increased in addition to an arrangement with only a pump and turbine wheel, which is also called a hydrodynamic coupling.

_ ^ G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp00100 /13^ January J 997. . .

·

and the torque of the turbine wheel compared to the pump wheel can vary greatly.

The possibility of transmitting power hydrodynamically offers the advantage of being able to transmit large amounts of power with a relatively high level of efficiency, low wear and tear and with small components. Furthermore, these components are mainly used during the start-up or, in the case of vehicles, the starting process of a consumer to be driven by a drive machine. In versions of

&iacgr;&ogr; Gear units with a hydrodynamic gear part in the form of a

hydrodynamic clutch and with downstream gear stages, the hydrodynamic clutch takes on the function of the starting clutch. The torque or power transmission therefore only takes place during a first gear stage, usually the starting process, via the hydrodynamic component. In the other gear stages, the hydrodynamic component is excluded from the power transmission. In addition, another hydrodynamic component in the form of a hydrodynamic retarder can be assigned to the transmission unit to implement braking stages and can either be integrated into the transmission or connected downstream of it. The same task can also be performed by hydrodynamic converters, whereby in the lower gear stages these can work with power splitting with the mechanical transmission stages. The hydrodynamic converter is usually used alone as a starting element during the starting process. In the other gear stages, the power is either transmitted purely mechanically, bypassing the hydrodynamic converter, or at least in the lower gear stages via the hydrodynamic converter and the mechanical transmission stages.

0 The current development in vehicle construction is partly

contradictory tendencies. In addition to the trend towards

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp001 QO /13 January 1397 * > · ·

With the introduction of more space, more comfort and better acceleration and deceleration for reasons of safety in all driving conditions, the aspect of environmental protection is becoming increasingly important. One way to reduce the CO ₂ emissions caused by vehicles can be to improve the

Energy conversion between the engine and the consumer in the drive train can be achieved. There is also a trend towards engines with smaller displacement, i.e. the torques are smaller and the nominal speeds are higher. The requirements for vehicle transmissions are also to be measured against this. The key assessment criteria for the quality of a transmission are

the driving performance; which is determined by the conversion range, the number of gears and gear ratios as well as the fuel consumption, influenced by the design of the drive ratio in the top gear and the efficiency of the gearbox.

For transmissions, therefore, an optimum efficiency and a conversion range with a gear ratio that allows the use of the best engine range or the minimum consumption line in the engine map as far as possible should be aimed for. In particular, a

0 Increasing the gear ratio in an adapted step a reduction of the

fuel consumption, particularly pollutant emissions and engine noise.

The automatic transmissions currently on the market already fulfil some of these tasks quite well. However, the operation of the internal combustion engine in the area of the lowest fuel consumption and the lowest pollutant emissions requires sufficient gearing, so that 5- and 6-speed transmissions are no longer a rarity in the vehicle sector. This often also increases the number of

0 of the transmission elements. In addition, according to the structure of the

gearbox additional components for the implementation of individual additional functions,

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOI 00 /13 January 1 _# (&psgr;7 . . ,,

for example, the generation of a braking torque. As a rule, a hydrodynamic retarder is often used for transmission configurations with a hydrodynamic clutch or hydrodynamic converter and a mechanical transmission part, but means must be provided to reduce the ventilation losses when the rotor impeller is idling, since when the retarder is completely empty there is always a residual torque that is caused by bearing friction and by the change in the spin of the air filling. The braking torque caused by the residual torque is very low, but can increase at high

&iacgr;&ogr; speeds can be very disruptive and lead to an unacceptably high

Heating of the retarder. A number of solutions are already known to reduce ventilation losses. These include the use of stator bolts and the possibility of circuit evacuation. However, these solutions are very complex to implement and require more space and therefore larger retarder dimensions. However, transmission configurations with hydrodynamic converters are also known, which use these to generate the braking torque.

0 Due to the trend towards engines with smaller displacement, which have a

As the connection diameters become smaller and smaller than before, it is becoming increasingly difficult to use hydrodynamic converters that can transmit the existing engine torque at low speeds with a smaller profile diameter. The disadvantage here is that the state of transmission capability only occurs at high speeds.

However, since torque and not power is needed to start moving, the excessive speeds result in a loss of power, which is reflected in increased fuel consumption. The associated loud engine noises pollute the environment.

G 05529/297 00 &THgr;05.3 / Voith Turbo GmBSl & Co. te /'fcurei lSv«AK/gwSo29S / ia*June 1997

When braking, in the known configurations the combustion engine remains coupled to the vehicle, i.e. the output of the transmission, and also causes noise due to unnecessarily high speeds.

The known transmissions also have a large variety of variants depending on the overall spread to be achieved and the adaptation to different internal combustion engines and the associated design of the blading of the individual elements.

The invention was therefore based on the task of improving the gearbox component for use in a drive train so that the disadvantages mentioned are avoided as far as possible. In particular, universal replaceability, which is characterized by the ability to generate sufficient driving and braking torques, adaptation to a large number of engines without a variety of parts and a large mechanical spread, and an increase in environmental compatibility, in particular low noise when starting, are to be aimed for. The number of components should be kept as low as possible.

Furthermore, a gearbox configuration with a small number of variants should be able to cover a wide range of possible applications.

The problem is solved by the features of claims 1 and 35. Advantageous embodiments are given in the subclaims.

A transmission unit for drive units for realizing at least two operating states - a first operating state for power transmission with at least two gear shift stages and a &ogr; second operating state for braking - comprises at least a first

hydraulic transmission part and a second, in series with the first

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret Ia^ AJC/spOOJQO / 13,January WÖ7.

hydraulic transmission part arranged mechanical transmission part. The hydraulic transmission part comprises at least two impellers - a primary impeller and a secondary impeller, which together form at least a toroidal working space that can be filled with operating fluid, whereby the coupling of the two impellers to the transmission input shaft and the mechanical transmission part takes place at least over a partial area of the first operating state in such a way that power is transmitted from the primary impeller via the secondary impeller to the mechanical transmission part. According to the invention, means are provided which in a second

&iacgr;&ogr; Operating state of one of the two impellers compared to the

hold and support the fixed transmission parts and connect the other impeller to the second mechanical transmission part. This means that a transmission unit that can be used as an automatic transmission is modified so that the functions of a hydrodynamic clutch and a hydrodynamic retarder are taken over by a single component, the hydrodynamic transmission element.

To implement the function of a hydrodynamic retarder, the following two basic variants are conceivable:

1) Allocation of the function of the stator impeller by fixing

relative to the stationary gear parts to the primary impeller and the function of the rotor impeller to the secondary impeller; 2) Allocation of the function of the stator impeller by setting relative to the stationary gear parts to the secondary impeller and the function of the rotor impeller to the primary impeller.

In both cases, the impeller that takes over the function of the rotor blade wheel is coupled to the gearbox output shaft via the mechanical gearbox part. Accordingly, the coupling options between the hydraulic and mechanical gearbox parts must also be provided for when designing the gearbox unit.

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la/ AK/spOOIOO/ 13. Januar 1907 ..

The hydrodynamic transmission element is therefore basically a hydrodynamic coupling, which at least indirectly connects the transmission input shaft to the transmission output shaft at least in the starting range and can be used in all other gear stages to generate a braking torque according to the locking of one of the two impellers and the connection of the other second impeller to the mechanical transmission part. This offers the main advantage that installation space can be saved and manufacturing costs can be reduced.

To implement the second operating state according to the first basic variant, the secondary impeller is connected to the mechanical transmission part in a rotationally fixed manner. First means are provided by means of which the primary impeller can be coupled at least indirectly to the transmission input shaft in a first operating state, which serves to transmit power and is referred to as "driving" when the transmission is used in vehicles. Furthermore, second means are provided for at least indirectly coupling the secondary impeller to the transmission input shaft during the remaining gear stages of the first operating state. The first operating state includes the forward and reverse gear stages.

The primary impeller is connected to the transmission input shaft, for example, by means of a so-called primary impeller coupling. The primary impeller is preferably secured to the stationary or fixed transmission parts, in particular the transmission housing, by means of at least one braking element. Furthermore, a so-called lock-up clutch is provided in the transmission, which connects the transmission input shaft directly to the secondary impeller, bypassing

0 of the primary impeller. This ensures that when filling

of the hydraulic transmission part in the first operating state, preferably

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la^ArOspOOIßO /13. Januar 1S97 · ·«

I· ·

only in a first gear stage, which is also referred to as the starting stage, the primary impeller takes over the function of the pump wheel of a hydrodynamic clutch. The primary impeller is driven and torque is transferred to the secondary impeller, which takes over the function of the turbine wheel, via the flow forces generated by the primary impeller rotation. In the remaining gear stages in the first operating state (i.e. the forward gears and partly also the reverse gears), the hydrodynamic transmission element remains essentially empty. The secondary impeller is then driven directly by the lock-up clutch from the transmission input shaft. If the primary impeller is completely decoupled from the transmission input shaft, however, this would lead to the medium air being circulated between the two impellers in the toroidal working chamber during these operating states, just as the operating medium would otherwise be in the filled state. For this purpose, it is preferably provided that the primary impeller rotates with the secondary impeller at the same speed or at the same speed during the further gear stages in the first operating state. The proportion of power withdrawn from the output by the drive of the primary impeller is relatively small and only depends on the weight of the primary impeller that is dragged along. The idling losses are thus significantly reduced.

In the second operating state, "braking", the hydraulic transmission part, which works as a clutch in the first operating state, is operated as a hydrodynamic retarder. The primary impeller takes over the function of the stator impeller, in which it is fixed and supported relative to the stationary transmission parts.

To implement the functional change between power transmission and braking according to the first basic variant, the two following options are essentially conceivable.

Secondary impeller is either

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOO^oj /13. January 1ß87 . . ..

1.1) via the output with the same direction of rotation with a possible connection between the mechanical transmission part and the transmission input shaft or

1.2) from the output side when the connection between the secondary impeller and the gearbox input shaft is released or the drive shaft coupled to the gearbox input shaft with the opposite direction of rotation relative to its direction of rotation during the start-up process

driven and takes over the function of the rotor blade wheel of a hydrodynamic retarder. In this operating state, the hydraulic &iacgr;&ogr; transmission part, i.e. the hydrodynamic transmission element, is at least partially

filled with operating fluid. This is circulated in the working space formed between the primary and secondary impellers due to the secondary impeller rotation and is braked on the fixed blades of the primary impeller. Means are provided to fix the primary impeller in place, which hold and support it in its position in relation to the stationary or fixed gear parts.

In the first option for changing the function, the hydrodynamic transmission element is filled to generate a braking torque and the secondary impeller remains coupled to the transmission output shaft via the engaged gear. Due to the overrun operation on the part of the output, the secondary impeller is driven by this without changing the direction of rotation in relation to the direction of rotation during the start-up process.

The blading of the two impellers is preferably designed at an angle, i.e. the blades are arranged at an angle to the dividing plane between the primary and secondary impellers. The blade direction, i.e. the inclination of the individual blades to the respective blade base, is selected such that in the first operating state,

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOO;qp / i3.»January 1ÖP7

especially during the start-up stage, the operating fluid is diverted from the space between two adjacent blades of the primary impeller driven by the transmission input shaft due to its rotation at the blade rears of the secondary impeller, i.e. a closed operating fluid circuit is formed between the primary and secondary impeller and torque is transmitted as a result. The term blade rear refers to the blading in the direction of rotation. This way in which the primary impeller works in relation to the secondary impeller is referred to as "spiked". Even in the operating state

&iacgr;&ogr; "Braking" the hydrodynamic transmission element is filled with operating fluid.

In the first option, the gear selected is retained in the mechanical transmission part. The primary impeller is fixed and the secondary impeller is driven in the same direction via the vehicle, in particular the transmission output shaft. The two impellers swap functions. The secondary impeller is now driven in the same direction of rotation as the primary impeller during the starting stage. The primary impeller is fixed and thus takes on the function of a stator of a hydrodynamic retarder. Due to the relative position of the impeller in relation to the separation plane

0 between primary and secondary impeller inclined

With this type of blading, only a portion of the flow energy of the operating medium generated by the rotation of the secondary impeller can be used to generate a braking torque and thus converted into heat. The operation of the secondary impeller in this operating state can be described as "escaped" compared to the primary impeller, which functions as a stator impeller. This type of realization of generating a braking torque by changing the function of the two impellers - primary and secondary impeller - can be carried out without additional effort from the engaged gear. In the

0 individual means are only to be provided which allow a determination of the

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIßO /13. Januar 1ßJ7 .,

primary impeller. Such a design is therefore very cost-effective.

Preferably, in order to reduce the noise during the braking operating state, the drive motor is decoupled from the secondary impeller, i.e., for example, the connection between the secondary impeller and the transmission input shaft or between the transmission and the drive motor is released.

However, the reaction torque generated by the slanted blading on the primary impeller, which leads to the braking of the output connected to the secondary impeller via the mechanical transmission part, is lower than when the secondary impeller works in a "skewing" manner relative to the primary impeller. Therefore, the direction of rotation of the secondary impeller, which functions as a rotor impeller in the "braking" operating state, is preferably reversed to generate a braking torque. This second option is implemented by activating at least one reversing stage that can be assigned to the individual gear stages or by activating the gear stages to implement a direction of rotation of the secondary impeller that is opposite to normal driving operation, i.e. a reverse gear. Due to the slanted blading, a closed circuit of operating fluid is then formed between the secondary impeller, which functions as a rotor impeller in this operating state, and the primary impeller, which functions as a stator impeller. The driven secondary impeller converts the introduced mechanical energy into flow energy when the circuit is full, which is converted into heat energy at the stationary primary impeller. This preferred option for changing the function of the hydrodynamic transmission element offers the advantage that

0 Translation of the secondary side impeller into fast and

In connection with the requirements of the hydrodynamic

G 0552&THgr; / Voith Turbo GmbH & Co. KG/ Ku ret la / AK/spOO1£Q /13. Januar 1887 · · · ·

The large transmission capacity of the circuit parts resulting from the component during the start-up process creates a large speed range, which can be covered by a braking state by changing the filling level. The braking moment can be controlled as with a conventional secondary retarder, i.e. one integrated in the transmission or

this downstream hydrodynamic retarder, by changing the filling level. Regarding the possibilities of changing the filling level and its implementation in detail, reference is made to the publication "Hydrodynamics in Drive Technology", Krauskopf-Verlag 1987 &iacgr;&ogr;. The disclosure content of this publication on

Changes in the filling level of hydrodynamic braking devices are included in the disclosure content of this application.

If the secondary impeller, i.e. the turbine wheel, is reversed in its direction of rotation in the braking state so that the circuit components are operated in parallel, the mechanical transmission part remains unaffected compared to known transmission configurations. Only the speed of the turbine or the secondary impeller is changed. The gear ratio to the output can be selected by selecting the appropriate outer ring of the output planetary gear set, for example, independently of the gear ratios in the individual gear stages of the first operating state. During the entire braking range, no gear shifting is required, i.e. from a maximum speed to a minimum speed, the braking torques are adjusted exclusively steplessly via the filling, as with a secondary retarder, with the advantage that braking can be carried out to lower speeds than otherwise possible without an additional boost with the selected arrangement. This means that a larger braking range is covered by the wear-free hydrodynamic brake.

0 The secondary impeller is in case of generation of a braking torque

by reversing the direction of rotation of the secondary impeller from the

G 0552&THgr; / Voith Turbo GmbH & Co. KG/ Kuret la / _# AKysp001£Q /13 January 19^7 · <

Drive machine decoupled. For this purpose, the lock-up clutch is preferably released in the transmission configuration described above. However, it is also conceivable to leave the through-coupling between the transmission input shaft and the mechanical transmission part activated and only decouple the transmission input shaft from the drive machine.

The primary impeller is connected to the transmission input shaft, for example, by means of a so-called primary impeller coupling. The primary impeller is fixed relative to the stationary or moving parts.

&iacgr;&ogr; fixed transmission parts, in particular the transmission housing,

preferably by means of at least one braking element. Furthermore, a so-called lock-up clutch is provided in the transmission, which connects the transmission input shaft directly to the secondary impeller, bypassing the primary impeller. This ensures that when the hydraulic transmission part is filled in the first operating state, preferably only in a first gear stage, which is also referred to as the starting stage, the primary impeller takes over the function of the pump wheel of a hydrodynamic clutch. The primary impeller is driven and torque is transferred to the secondary impeller, which takes over the function of the turbine wheel, via the flow forces generated by the primary impeller rotation. In the other gear stages in the first operating state (i.e. the forward gears and partly also the reverse gears), the hydrodynamic transmission element remains essentially unfilled. The secondary impeller is then driven directly by the transmission input shaft via the lock-up clutch. If the primary impeller is completely decoupled from the transmission input shaft, this would result in the medium air being circulated between the two impellers in the toroidal working chamber during these operating states, just as the operating medium is circulated in the filled state. For this purpose, it is preferably provided that the primary impeller is circulated during the further gear stages in the

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret li^/./y^spOOipg /13 January 18»7 · « · ·

first operating state with the secondary impeller at the same speed or at the same speed. The proportion of power withdrawn from the output by the drive of the primary impeller is relatively small and only depends on the weight of the primary impeller that is being dragged along. The idle losses are thus significantly reduced.

A gear unit in which the braking function is implemented according to the first basic variant, i.e. the primary impeller is assigned the function of the stator impeller, is preferably

&iacgr;&ogr; modified so that both impellers - the primary impeller

and the secondary impeller - are completely decoupled from the drive or gearbox input shaft when in operation, i.e. both impellers are stationary. This offers the advantage that ventilation losses due to the circulation of air between the two impellers can be completely avoided.

To implement the second operating state of "braking" according to the second basic variant, the secondary impeller is fixed in relation to the stationary gear parts and supported by them. The secondary impeller takes over the function of the stator impeller. The primary impeller, which is preferably coupled to the gear input shaft in a rotationally fixed manner, is driven via the output in the same direction of rotation as during the start-up process. It takes over the function of the rotor impeller. In detail, this means that the operating fluid is circulated in the toroidal working space in the same flow direction as during the start-up process, but during the braking process it hits the fixed blades of the secondary impeller and is thus braked.

0 For the structural design, first means are required by which the

Gearbox input shaft can be coupled to the second mechanical gearbox part

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret lay _# /y^sp001flQ/13 January 1S»7

and second means by which the secondary impeller can be coupled to the connection between the transmission input shaft and the mechanical transmission part are provided. A further third means serve to fix the secondary impeller in the second operating state. The primary impeller is preferably connected to the transmission input shaft in a rotationally fixed manner.

Here too, the individual means are preferably designed in the form of switching elements, in particular power switching elements. The first and second means preferably comprise clutch devices, the third means at least one braking device.

.

In this preferred embodiment for realizing the second operating state according to the second variant, the braking torque can be adjusted solely by changing the filling level in the toroidal working chamber and by fixing the secondary impeller. This enables particularly rapid braking.

Preferably, the blades of the primary and secondary impeller are inclined in such a way that both during the start-up process and during the second operating state, the two impellers work in a spiking manner. This means that high reaction torques are generated on the secondary impeller.

Another theoretically conceivable possibility for braking

5 according to the second basic variant is to change the direction of rotation of the

primary impeller, for example by engaging the reverse gear. In this case, however, an interruption of the power flow from the drive engine to the primary impeller is required, for example by decoupling the transmission input shaft from the

0 drive machine.

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO /13 January 1£

The individual options for coupling and decoupling the primary and secondary impeller to the transmission input shaft as well as for securing the individual impellers relative to the stationary transmission parts can be implemented using power shift elements. This applies analogously to the implementation of the gear stages in the mechanical transmission part. These

Load switching elements are preferably designed in the form of friction elements that can be pressed against one another, in particular in a lamella design. Other designs are conceivable. The specific selection of the type of load switching elements and their use, however, depends on the requirements of the application and is at the discretion of the specialist.

A large number of variants are conceivable for the design of the mechanical gear part. It is possible to implement the individual gear stages using spur gear stages and/or planetary gear sets. In detail, so-called Ravigneaux planetary gear sets are used, for example. Preferably, however, a mechanical gear part is selected which is relatively small in terms of its length and nevertheless allows for a large speed-torque conversion. A preferred design comprises at least three planetary gear sets - a first, a second and a third planetary gear set. The individual planetary gear sets each comprise at least one sun gear, a ring gear, planetary gears and a carrier. The planetary gear sets are coupled to one another. At least one clutch and/or one brake element is assigned to each planetary gear set. The individual power shift elements are actuated depending on the current driving conditions and the driver's wishes and are preferably controlled by a control device, for example the drive control.

The operating state "braking" can also be divided into at least two 0 partial operating states, in particular if, according to the

switched gears during the switching process a variety of

G 0552S / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp00100 /13 January 1&THgr;97

&bull; <

Load switching elements are to be brought into engagement or disengaged. It is preferably provided that some of the load switching elements remain actuated.

The solution according to the invention offers the advantage that several operating states can be realized with a transmission concept that has only one hydraulic transmission part for power transmission. By assigning the "clutching" and "braking" functions to a hydrodynamic component, installation space is saved. Furthermore

&iacgr;&ogr; this concept fits into the prevailing development trend, which

an ever smaller hydrodynamic component during the driving operating state, and thus serves to reduce fuel. Another significant advantage is that with a gearbox or gearbox configuration with a very small number of variants, optimal adaptation to different engines and vehicles can be achieved mainly by controlling the filling of the hydrodynamic gear element, i.e. the gearbox can be used universally over a large power range. It is also possible to simplify the damping of vibrations. When constantly starting and braking, i.e. in stop-and-go traffic, there are significant reductions in the noise emissions of the drive engine.

By controlling the filling, the speed behavior of any drive machine, especially any internal combustion engine,

5 can be optimally influenced with regard to noise and exhaust emissions when starting off.

Particularly in the braking operating state, the functional assignment has significant advantages over conventional solutions, which essentially provide a separate retarder behind the transmission or generate the braking torque with the hydrodynamic converter. With the solution according to the invention, sufficient constant braking torques are possible down to low speeds. During the entire

G 05529 / Voith Turbo GmbH & Co. KG/ Ku ret la/ AK/spOOIOO /13 January 1997

No switching is required in the braking mode. The noise level in the braking mode is therefore very low. During adaptation and stop braking, the motor remains constantly disconnected and runs idle. Only when a critical oil temperature is reached is the motor revved up a little to improve the water supply, but this will only be necessary on longer downhill journeys. Fast reaction times when changing functions are preferably achieved by filling the accumulator. The hydrodynamic component requires a smaller oil filling than a hydrodynamic converter.

During the driving operating state, there are no retarder losses during driving operation, since both impellers - primary impeller and secondary impeller - preferably rotate together and the retarder is emptied.

The gear unit designed according to the invention is characterized by universal replaceability, low fuel consumption, high environmental compatibility, low manufacturing costs and a long service life. The possible driving and braking torques are

0 according to the design of the hydrodynamic component

The coupling with the subsequent mechanical gear stages enables a high spread and allows use in urban and intercity vehicles. The transmission is also within the transmission contour of conventional transmission variants.

The share of the hydraulic transmission element in the power to be transmitted is reduced compared to conventional solutions. The hydrodynamic transmission element with the two functions "clutching" and "braking" offers the possibility of designing the starting process in such a way that

0 optimal function of the engine during start-up and in hydrodynamic

area. In today's common torque converter transmissions, the

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp00100 / 13 January 1997

Engine start-up is determined by the converter resistances, which depend on the geometry of the blades and the profile diameter of the converter. As a rule, the equilibrium state only occurs at unnecessarily high speeds, which is associated with increased fuel consumption, emissions and higher engine noise. Both are, however, important arguments today when choosing a transmission. In detail, this means that the transmission creates little resistance in the lower speed range so that the engine comes out of this unfavorable range, i.e. the generation of small torques and soot formation, as quickly as possible. The engine speed is regulated at a desired speed level during the subsequent acceleration of the vehicle by controlling the filling of the clutch. By choosing the appropriate transmission capacity of the clutch, the drive engine is coupled to the mechanical transmission with almost no slip. When driving in the mechanical gears, the hydrodynamic transmission element rotates preferably coupled in the empty state, i.e. there are no ventilation losses.

By using only a single hydrodynamic transmission element in the overall transmission, the number of possible transmission variants can be reduced, since adaptation to the different operating conditions can be achieved simply by changing the filling level.

In particular, this concept is particularly applicable to multi-speed transmissions, especially five- and six-speed transmissions.

By assigning the functions "clutching" and "braking" to a hydrodynamic transmission element, the following properties can be achieved. The required torque 0 when driving and braking can be adjusted by filling control. This

allows a wide range of torque adjustment from zero to a

G 05529/Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOlOO /13 January 1997

Maximum torque, good dynamic behavior due to a small-volume flow circuit and no loss in repeat processes due to priority emptying of the hydrodynamic gear element into a reservoir.

The good environmental compatibility is achieved through lower noise when starting due to low engine speed, lower noise due to the engine being disconnected when braking, as the engine runs at idle during all adaptation and holding braking, a lower oil change quantity as well as longer oil change intervals due to the complete exchange of the oil quantity when changing the oil and longer oil change intervals due to lower temperature stress due to large circulating oil quantities when braking and starting. Furthermore, due to the design of the hydrodynamic transmission element, a much larger range for wear-free braking can be achieved.

When starting off, the task is to couple the engine to the gearbox after it has reached its full engine torque. On the way to the coupling point, the gearbox torques should be as low as possible so that this area, which is unfavorable for the engine, can be passed through as quickly as possible. Starting off is therefore divided into two areas:

1. Run-up of the engine to the coupling point

2. Control behaviour after reaching the coupling point

There are several ways to achieve these properties:

1. Control of a constant filling independent of the engine speed

2. Speed-dependent control of the filling

3. Inserting a specific amount by controlling the switch-on time of the storage

The control behavior after reaching the coupling point is characterized by a speed control of the engine.

G 0552&THgr; / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO /13 January 1997

In the first case, the level of filling depends on the desired transmission capacity derived from the characteristics of the drive engine. By setting the target pressure accordingly, the hydrodynamic transmission element already has the desired level of filling when the drive engine is idling, so that when accelerating the desired coupling point is reached with almost no change in the level of filling. The primary impeller must therefore already be coupled when the idle speed is reached.

&iacgr;&ogr; When the primary impeller is disconnected, the

Working space, whereby it is possible for the filling to adjust to the desired value during start-up by throwing out the excess operating fluid.

With speed-dependent control of the filling, the working space of the hydrodynamic transmission element is emptied. The desired filling is only set when the load sensor specifies the appropriate setting and the drive machine reaches a certain speed. The primary impeller clutch can be activated or released for this purpose in accordance with a configuration for implementing the braking process in accordance with the first basic variant, whereby if the primary impeller clutch is activated, it should be closed as soon as possible after the load sensor is activated or after the end of a braking signal.

' ■ .

Furthermore, it is possible to let a specific amount of operating fluid into the working area by controlling the switch-on time of the hydrodynamic gear element’s storage tank integrated in the operating fluid supply system. To do this, the working area of the hydrodynamic gear element is 0 in the initial state.

When a certain level is reached,

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO /13 January 1897

Depending on the engine speed and the corresponding specification of the load sensor, an engine-specific amount of oil is pushed into the working chamber through the reservoir integrated in the operating fluid supply system of the hydrodynamic transmission element. The primary impeller clutch can be activated or released. In the

released state, however, it should be activated as soon as possible after actuation of the load sensor or after termination of an EJbrake signal. For all stopping processes, however, if the same initial state is desired, care must be taken that before the release of the &iacgr;&ogr; primary impeller clutch, the working space of the hydrodynamic

Gear element can be emptied.

As soon as the coupling point is reached, the control system switches to a speed control of the drive engine. The activation of the accumulator is switched off. As soon as the vehicle starts moving and the speed of the secondary impeller increases, the filling of the working chamber of the hydrodynamic transmission element increases further due to the speed control and tries to keep the engine at the clutch speed. When the working chamber is completely filled, the

0 connection speed of the mechanical transmission is then approximately reached.

By closing the lock-up clutch between the transmission input shaft and the secondary impeller, the drive motor is fully synchronized with the output side without any significant change in speed and the vehicle is in the first mechanical gear.

A damping element is provided to dampen vibrations during the start-up process. Due to the purely hydraulic start-up stage, a single-stage spring characteristic is sufficient, i.e. the damping element comprises at least one spring element. This is preferably located between the drive side and the drive of the

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO /13 January 1&THgr;&THgr;7

Outer plates of the lock-up clutch are arranged. Other possibilities are also conceivable.

It is also possible to create a hydrodynamic transmission element, comprising at least one primary and one secondary impeller as a pre-assembled assembly with a housing. The means for coupling to a driving shaft and for securing are directly assigned to the individual impellers, in particular the primary impeller, and the latter are mounted on the housing.

Due to the good efficiency of the hydrodynamic component, which is definitely better than that of a hydrodynamic converter, the hydrodynamic component can remain active in the lower gears. This significantly improves the driving behavior and gearshift transitions thanks to the smooth hydraulic connection of the engine. The use of the lock-up clutch can be dependent on the acceleration of the vehicle or can be placed in the upper speed range, where purely mechanical operation no longer causes any problems.

When changing gears, the same requirements apply as for other transmissions. The drive unit, in particular the combustion engine, must be brought to the new connection speed as directly and smoothly as possible by the corresponding switching elements. To do this, switching on and off takes place with a slight overlap and the gear to be switched on is equipped with the corresponding pressure ramp.

When switching between groups, the group clutch synchronizes the combustion engine to the corresponding &ogr; connection speed. After that, the gearshift is carried out quickly, without a great build-up of pressure.

known overlap of the gear changes. This creates

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOO100/13 January 1997

no significant impact on the output because only small, internal gear masses are adjusted in their speed.

The transmission also has good efficiency across the entire range and there are no setbacks compared to currently known transmissions in terms of shifting comfort and driving behavior. During the "driving" operating mode, the hydrodynamic clutch element is operated with maximum filling, has very little slip and therefore excellent efficiency.

&iacgr;&ogr; which can be between 90 and 99% depending on load and speed. This

Values are not achieved by any hydrodynamic converter. The hydrodynamic component, which works as a clutch during the start-up process, engages hard. Nevertheless, it remains a hydraulic transmission element with all its advantages, such as damping vibrations and reducing noise. In all subsequent gear shifts, the slip of the hydrodynamic component is increased, the clutch is softer and reaches values that correspond at least to the slip of a hydrodynamic converter. The shifting of the individual gears in the first

0 operating state can be achieved quickly, the inevitable slip

can be moved into the hydrodynamic component and then reduced again by increasing the filling. This allows comfortable transitions to be created while simultaneously reducing the load on the switching elements for the implementation of the individual gear steps.

Even in the event of sudden load changes, the slip of the hydrodynamic component can also be increased for a short time, resulting in a hydraulically soft connection, and the support in overrun mode is also very low. The dreaded load change shock should then

0 should not be an issue. In addition, the characteristic curve of the used

elastic damper has better properties during load changes. The

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO / 13 January 1997

The hydrodynamic component is then bridged in the "driving" operating state when the switching of the individual gears in the first operating state no longer causes a loss in switching comfort. This function is ensured by appropriate control of the filling and emptying processes.

Furthermore, the solution to the problem according to the invention offers the possibility of creating a pre-assembled hydrodynamic assembly according to claims 40 and 41.

The solution according to the invention is explained below with reference to figures.

Figure 1 shows a simplified schematic representation of the

Configuration of a preferred embodiment of a transmission designed according to the invention for generating the

braking torque according to the first basic variant; Figure 2 illustrates a circuit diagram for the operation of the individual

Power shift elements of a transmission according to Figure 1; Figure 3a and 3b illustrate schematically the operation of the hydrodynamic transmission element during the

Starting process in the first operating state and during

second operating state;

Figure 4 shows an arrangement of an attenuator; Figure 5 illustrates the structure of an attenuator; Figure 6 illustrates schematically in a simplified representation the

Configuring a preferred version of a

inventively designed gear for generating the

Braking torque according to the second basic variant; Figure 7a shows a simplified schematic representation of a and 7b shows a further configuration of an inventively designed

Gearbox to generate the braking torque after the first

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la/ AK/spOOIOO / 13 January 1997

Basic variant and the switching diagram for operating the individual load switching elements.

Figure 1 illustrates schematically, using a simplified representation of an axial section, the structure of a gear unit 1 designed according to the invention in a preferred embodiment. The gear unit 1 has a gear input shaft E and a gear output shaft A. The gear unit 1 further comprises a first hydraulic gear part 2 and a second mechanical

&iacgr;&ogr; Transmission part 3. The first hydraulic transmission part 2 comprises a

hydrodynamic transmission element with at least two impellers, a first impeller and a second impeller. The first impeller is referred to as the primary impeller 4 and the second impeller as the secondary impeller 5. The primary impeller 4 and the secondary impeller 5 together form at least one toroidal working space 6, which can be filled with operating fluid. For this purpose, an operating fluid supply unit, not shown in detail here, is assigned to the toroidal working space 6. When the transmission designed according to the invention is used in a vehicle, the hydraulic transmission part can be operated in two different operating states - a first operating state, which is referred to as "driving", and a second operating state, which is referred to as "braking", respectively as a hydrodynamic clutch and as a hydrodynamic retarder. For this purpose, the individual impellers - the primary impeller 4 and the secondary impeller 5 - are each assigned different functions.

During the first operating state, especially during the start-up process, the primary impeller 4 works as a so-called pump wheel and the secondary impeller 5 as a turbine wheel. In the second operating state "braking", the primary impeller 4 is assigned the function of

0 stator blade wheel of a hydrodynamic retarder. The

Secondary impeller 5 then takes over the function of the rotor impeller.

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp00100 /13 January 1&THgr;97

To implement these functions, appropriate means must be provided that enable a functional assignment in the manner mentioned. The secondary impeller 5 is permanently connected to the mechanical transmission part 3 via a connecting shaft 7 in a rotationally fixed manner. The connecting shaft 7 can be coupled to the transmission input shaft E via a so-called through coupling, which is also referred to as a bridging clutch ÜK. The secondary impeller 5 can also be connected to the transmission input shaft E via this coupling. The primary impeller 4 is connected to the transmission input shaft E by means of a so-called

&iacgr;&ogr; Primary impeller clutch PK can be coupled to the transmission input shaft E.

The primary impeller 4 is preferably arranged in a rotationally fixed manner on a connecting shaft 8, wherein the connecting shaft 8 can be connected to the gearbox input shaft E by the primary impeller clutch PK. A braking element, which is referred to here as primary impeller brake PB, is assigned to the connecting shaft 8. This primary impeller brake PB is fixed to the frame on a stationary transmission part, preferably on the transmission housing 9 indicated here.

The secondary impeller 5 can be coupled to the second mechanical transmission part 3 via the connecting path 7. In the case shown, the second mechanical transmission part 3 comprises three planetary gear sets, a first planetary gear set PRI, a second planetary gear set PRM and a third planetary gear set PRIII. The individual planetary gear sets each comprise at least one first sun gear - designated la for the first planetary gear set PRI, Ha for the second planetary gear set PRII and lila for the third planetary gear set PRIII, a ring gear, planetary gears and a web. The ring gears of the individual planetary gear sets are designated Ib for the first planetary gear set PRI, Nb for the second planetary gear set PRM and INb for the third planetary gear set PRIII. The 0 planetary gears are assigned the reference numbers for the first planetary gear set PR I Ic,

for the second planetary gear set PRII lic and for the third

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp00100 /13 January 1997

Planetary gear set PRIII IHc is assigned. The webs of the individual planetary gear sets are designated ld, Hd and IHd. At least a first gear element of the first planetary gear set IPRI, the second planetary gear set PRII and the third planetary gear set PRIII are connected to one another via a connecting shaft 10. Preferably, these gear elements are arranged on the connecting shaft 10 in a rotationally fixed manner. The first gear element of the first planetary gear set is formed by the web Id, of the second planetary gear set PRM by the ring gear lib and of the third planetary gear set PRIII by the sun gear lila. Another

&iacgr;&ogr; second transmission element of the first and second planetary gear set PRI

or PRII are also coupled to one another. The second gear elements are formed in the first planetary gear set PRI by the sun gear la and in the second planetary gear set PRII by the sun gear Ha. For this purpose, both sun gears - the sun gear of the first and second planetary gears - are preferably arranged in a rotationally fixed manner on a common shaft 11, which can be designed as a hollow shaft. The connecting shaft 7 between the hydraulic gear part 2 and the mechanical gear part 3 can be coupled to the first planetary gear set PRI via a first coupling element K1. A further second

0 Coupling element K2 is the connection, preferably the connecting shaft

between the two second transmission elements of the first planetary gear set PRI and the second planetary gear set PRII, which are each formed by the sun gears la and Ha, at least indirectly assigned.

A second transmission element of the third planetary gear set PR III is formed by the web IHd. The web IHd can be connected in a rotationally fixed manner to the transmission output shaft A. Preferably, the web HId of the third planetary gear set PR III is rotationally fixed to the transmission output shaft

0. A third transmission element of the third planetary gear set PRIII

is formed by the ring gear IHb. The ring gear IHb is connected via a further

G 05539 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO /13 January 1897

The third coupling element K3 can be connected in a rotationally fixed manner to the web and thus to the gearbox output shaft.

Each planetary gear set PRI, PRM or PRIII is assigned a brake element. A first brake element &Bgr;&Iacgr; serves to lock the

Connection between the two sun gears la and Ma of the two planetary gear sets PRI and PRII. A second brake element B2 is used to fix a third gear element of the second planetary gear set PRII, which is formed by the web Nd. A third &iacgr;&ogr; brake element B3 is connected to the third gear element of the third

planetary gear set PRIII, which is formed by the ring gear IHb.

The detailed design for the arrangement described above is at the discretion of the specialist. For the implementation of individual operating states and gear stages, the assignment of the individual clutch and brake elements K and B to the mechanical transmission components implementing the individual gear stages can be determined accordingly. The design of the mechanical transmission part can also be carried out differently. In detail,

0 for example, gear stages in the form of spur gear stages, planetary gear stages and

Combinations of both are conceivable. The individual brake elements are preferably attached to stationary components of the gearbox, preferably to the housing or the housing wall 9.

Various variants are conceivable for the design of the individual power shift elements, the lock-up clutch ÜK, the primary vane wheel clutch PK, the primary vane wheel brake PB, the individual clutch elements K and the individual brake elements B. Preferably in a friction disc design, especially in a multi-disk design. However, the expert also has a variety of options available here based on the state of the art.

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la/ AK/spOOIOO /13 January 1997

Figure 1 illustrates a preferred embodiment of a mechanical transmission part in combination with the hydrodynamic transmission element operated with a change in function. Other embodiments of the mechanical transmission part are conceivable.

Figure 2 shows an overview of the operating states and the individual gear stages achieved with the transmission described in Figure 1. As already explained, the transmission shown in Figure 1 is

&iacgr;&ogr; described gear unit is a preferred embodiment, based on

which is intended to show and explain the functioning of a hydraulic transmission part 2 which can be operated as a hydrodynamic clutch or as a hydrodynamic retarder. In detail, a distinction is made between the two basic operating states of driving and braking. In the example shown, the driving operating state comprises gears 1 to 6 and two reverse gears. The braking operating state comprises two braking stages - a first braking stage and a second braking stage. In the first gear of the first operating state, the so-called starting gear, the primary impeller clutch PK is actuated and thus connects the transmission input shaft E to the primary impeller 4 via the connecting shaft 8. The connection between the hydraulic transmission part 2 and the mechanical transmission part 3 is implemented via the first clutch element K1. Furthermore, the second and third braking elements B2 and B3 are actuated. The hydraulic structural unit 2, in particular the toroidal working chamber 6, is filled with operating fluid in this state. The power flow or the power transmission requires the primary impeller 4, the secondary impeller 5 via the first clutch element K1, the first planetary gear set PRI, in particular the ring gear Ib of the first planetary gear set PRI, via the transmission input shaft E, which can be coupled at least indirectly to a drive machine not shown here, the primary impeller clutch PK ₁ ,

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO / 13 January 1997

planetary gear set onto the web IHd of the third planetary gear set and thus the transmission output shaft A, which can be brought into drive connection at least indirectly with a device to be driven, for example the wheels of a vehicle.

The hydraulic transmission part 2 works as a hydrodynamic clutch during the starting process. Filling takes place during the individual gear stages in the driving operating state only during the starting process. During the transition to the second gear stage, the hydraulic transmission part 2,

&iacgr;&ogr; especially the toroidal working chamber 6, emptied. The first

Clutch element K1 and the third brake element B3 remain activated, as does the primary impeller clutch PK. The second brake element B2 is released and the first brake element B1 is activated instead. With this gear, the lock-up clutch IJK, which connects the transmission input shaft E with the secondary impeller 5 or the connecting shaft 7, can be activated or released. This depends on the extent to which the function of the hydraulic transmission element 2 as a hydrodynamic clutch extends into the second gear. In this case, the working chamber 6 of the hydraulic transmission part 2 is still filled even during the second gear. However, if a through-coupling takes place between the transmission input shaft E and the mechanical transmission part 3, the toroidal working chamber 6 of the hydraulic transmission part 2 is emptied. In this case, the power flow occurs from the transmission input shaft E via the lock-up clutch ÜK, the connecting shaft 7, the first clutch element K1 to the ring gear Ib of the first planetary gear set PRI, to the web Id of the first planetary gear set via the connecting shaft 10 to the web UId of the third planetary gear set PRIII and thus the transmission output shaft A.

0 In this second gear stage, due to the torsion-proof connection

between secondary impeller 5 and connecting shaft 7 this with

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO /13 January 1997

driven. Even if the toroidal working chamber 6 were emptied, this would result in ventilation losses due to the circulating air masses between the two impellers - the secondary impeller 5 and the primary impeller 4. Therefore, the primary impeller clutch PK is preferably also actuated during all driving stages.

This enables the primary impeller 4 to rotate together with the secondary impeller 5 at the same speed or rotational speed. This avoids ventilation losses in the power transmission due to circulated and braked air masses between the two impellers, and no additional

complex equipment, such as is required in the current state of the art, for example in the case of retarders to avoid power losses, is necessary.

In the third gear, in addition to the lock-up clutch ÜK and the primary impeller clutch PK, the first clutch element K1, the second clutch element K2 and the third brake element B3 are activated. All other powershift elements are disengaged. The power flow thus takes place via the transmission input shaft E, the lock-up clutch UK ₁ , the connecting shaft 7 via the first clutch element K1 to the first planetary gear set PRI, in particular to the ring gear Ib of the first planetary gear set PRI. A further power component is transmitted via the second clutch element K2 to the sun gear la of the first planetary gear set PRI. The power components which in turn are brought together at the web Id of the first planetary gear set PRI are transmitted via the web IHd of the third planetary gear set PRIII to the transmission output shaft A.

In the fourth gear, the first clutch element K1, the third clutch element K3, the lock-up clutch ÜK, the primary impeller clutch PK and the second brake element B2 are actuated.

All other load switching elements are disengaged. Using the second

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO /13 January 1897

< itii ·· * »»···&diams;

Braking element B2, the carrier Hd of the second planetary gear set PRII is locked. The ring gear HId of the third planetary gear set PRIII is connected to the carrier of the third planetary gear set INd in a rotationally fixed manner. The power is thus transmitted from the transmission input shaft E via the lock-up clutch L)K _1, the connecting shaft 7, the first

Coupling element K1 to the ring gear Ib of the first planetary gear set PRI, via the second planetary gear set PRII, the connecting shaft 10 to the planetary gears HIc of the third planetary gear set PRIII, which drive the web llld of the third planetary gear set PRIII, coupled to the ring gear IHb, to the transmission output shaft A.

In the fifth gear, only the second brake element B2 is released and the first brake element B1 is activated. This means that the connection between the first planetary gear set PRI and the second planetary gear set PRII, in particular the connecting shaft 11, is fixed.

The sun gears la and Ha of the two planetary gear sets PRI and PRII are therefore stationary. The power transmission itself takes place again via the input shaft E, the lock-up clutch ÜK, the connecting shaft 7, the first clutch element K1, the ring gear Ib of the first planetary gear set PRI and from there via the web Id of the first planetary gear set PRI to the web llld of the third planetary gear set PRIII and thus the transmission output shaft A.

The sixth gear differs from the fifth gear in that all three clutch elements K1, K2 and K3 are actuated, while all brake elements are released.

A reversal of the direction of rotation in the reverse gears of the first operating state is also achieved by certain combinations of 0 operation of the individual powershift elements, i.e. the clutch and

Brake elements are implemented. For this purpose, essentially in a first

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la/ AK/spOOIOO/13 January 1997

In reverse gear, the primary impeller clutch PK, the second brake element B2, the second clutch element K2 and the third brake element B3 are activated. In a second reverse gear stage, the third brake element B3 is released and the third clutch element is activated. The release and activation of the individual clutch and brake elements to implement the reverse gear stages enables the direction of rotation of the transmission output shaft A to be reversed.

Preferably, according to the individual engaged &iacgr;&ogr; gear stages, which also serve as group clutch and group brake

The load switching elements K3 and B3 are each actuated and the other brake and clutch elements are released or engaged. This divides the braking operating state into at least 2 sub-areas.

In the second operating state "braking", the hydraulic, in particular hydrodynamic, transmission part 2 is operated as a brake. The function of the stator impeller is taken over by the primary impeller 4. This is held in place by the primary impeller brake PB. With the transmission shown in Figure 1, two braking stages can essentially be achieved by engaging the individual reverse gears in the mechanical transmission part 3. In both braking stages, the overrunning clutch is released for this purpose. However, this can remain activated provided that the drive machine is decoupled from the transmission.

To couple the connecting shaft 7 with the second transmission part 3, the first clutch element K1 is activated. Furthermore, in a first braking stage, the third clutch element K3 is closed, which means that ring gear IHb of the third planetary gear set PRiII is rotationally fixed to the web HId 0 of the third planetary gear set PRIII and thus to the transmission output shaft A

In a second braking stage, the third clutch element K3

G 05529 / Voith Turbo GmbH & Co. KG/ Ku ret la / AK/spOOIOO /13 January 1997

&bull; *

released and the third brake element B3 is activated. The second brake element B2 is also closed in both braking stages, i.e. the carrier lld of the second planetary gear set PRII is stationary. .

In this operating state, the secondary impeller 5 is driven by the transmission output shaft A via the individual

switched transmission elements of the mechanical transmission part. It thus takes on the function of the rotor blade wheel of a hydrodynamic retarder. The working circuit in the toroidal working chamber 6 has an opposite flow direction to &iacgr;&ogr; that in the first operating state of the hydraulic transmission part when starting

set flow direction.

In the first operating state - "driving" -, especially during the start-up process, the hydraulic transmission element 2 operates in a spearing manner. When the braking stages are implemented via the reverse gear stages, in the second operating state - "braking" - the operating mode is also spearing due to the blading of the impellers and the changed direction of rotation of the secondary impeller.

In Figures 3a and 3b, these working methods are illustrated in a simplified, schematic manner in a cylindrical section through the hydraulic transmission part 2, in particular the two impellers - the primary impeller 4 and the secondary impeller 5. The same reference numerals are used for the same elements.

Figure 3a illustrates the operation of the hydrodynamic gear element during the start-up process. This shows that the operating fluid from the space between two adjacent blades and 4.2 of the primary impeller 4 driven by the gear input shaft is guided to the rear sides of the blades due to its rotation, here for clarification 5.1 and 5.2 of the

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOI 00 /13 January 1897

Secondary impeller 5, is diverted, i.e. a closed operating fluid circuit is formed between the primary and secondary impeller and torque is thereby transmitted. This mode of operation of the primary impeller in relation to the secondary impeller is referred to as "spiked".

Even in the braking operating state, the hydrodynamic transmission element is filled with operating fluid. Due to the inclined blading, a closed circuit of operating fluid is then formed between the

&iacgr;&ogr; operating state as rotor blade wheel acting secondary blade wheel and

the primary impeller, which acts as the stator impeller. The driven secondary impeller converts the mechanical energy introduced into flow energy when the circuit is full, which is converted into heat energy at the stationary primary impeller. The secondary impeller works in the opposite direction to the start-up process.

Figure 3a shows the operation of the hydraulic transmission element 2 as a clutch during the starting process and possibly during a first part of another gear in the first operating state "driving". In this case, the primary impeller 4 is driven by the transmission input shaft E. The direction of rotation is determined by the output shaft of a working machine that is either directly coupled to the transmission input shaft or by upstream power transmission elements. When the primary impeller 4 rotates

5 opposite the secondary impeller 5, the blading is such

to each other so that the hydraulic transmission part works in a spiking manner.

In Figure 3b, the hydraulic transmission part 2 is shown in the operating state braking when the direction of rotation of the secondary impeller is reversed. In

0 In this operating state, the primary impeller 4 is opposite the housing

the coupling is stationary and fixed to the frame and the secondary impeller 5 is

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp00100 /13 January 1&THgr;97

37""

via the reverse gears in the mechanical transmission part from the transmission output shaft A. Due to the exchange of the drive sides between the operating states of driving and braking, a working circuit is generated in the toroidal working chamber 6, which in braking mode is directed opposite to that in coupling mode. The operating mode of both paddle wheels is also spiking.

The developed representation of the blading of the two impellers in Figures 3a and 3b illustrates the inclination of the individual

&iacgr;&ogr; blading compared to a primary and secondary impeller

in the installation position formable parting plane E ₁ -.

Figure 4 uses a section of a transmission diagram to illustrate the arrangement of a damping element 21 upstream of the hydrodynamic component. This is preferably arranged between the transmission input side and the drive of the outer plates of the lock-up clutch LJK.

The structure is shown in detail in Figure 5. The damping element 21 0 is disk-shaped and has a plurality of

torque supports 22 of a certain diameter d that can be arranged in the circumferential direction and energy storage units in the form of spring elements 23 arranged therebetween.

5 Figure 6 illustrates schematically using a simplified representation

an axial section of the structure of a gear unit 25 designed according to the invention for generating the braking torque according to the second basic variant in a preferred embodiment. The gear unit 25 has a gear input shaft E, a

0 transmission output shaft A, a first hydraulic transmission part 26 and

a second mechanical transmission part 27. The first hydraulic

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO /13 January 1997

The transmission part 26 comprises a hydrodynamic transmission element with at least two impellers - a primary impeller 28 and a secondary impeller 29. The primary impeller 28 and the secondary impeller 29 together form at least one toroidal working space 30, which can be filled with operating fluid. For this purpose, a operating fluid supply unit, not shown in detail here, is assigned to the toroidal working space 30. The hydraulic transmission part is when the transmission designed according to the invention is used in a vehicle in two different operating states - a first

&iacgr;&ogr; operating state, which is called "driving" and a second operating state,

which is referred to as "braking", can be operated as a hydrodynamic clutch and as a hydrodynamic retarder. For this purpose, the individual impellers 28 and 29 are assigned different functions. During the first operating state, in particular during the start-up process, the primary impeller 28 works as a so-called pump wheel and the secondary impeller 29 as a turbine wheel. In the second operating state "braking", the secondary impeller 29 is assigned the function of the stator impeller of a hydrodynamic retarder. The primary impeller 28 then takes over the function of the rotor impeller.

To implement these functions, appropriate means must be provided that enable a function assignment in the manner mentioned. The primary impeller 28 is permanently connected to the transmission input shaft E in a rotationally fixed manner. The second mechanical transmission part 27 can be coupled to the transmission input shaft E via a so-called through coupling, which is also referred to as a bridging clutch ÜK. The secondary impeller 29 can also be connected to the transmission input shaft E via this coupling. The secondary impeller 29 is also connected to the mechanical transmission part 27 by means of a so-called secondary impeller coupling TK.

0 in particular the connecting shaft 31 between the lock-up clutch ÜK

and mechanical transmission part 27. The secondary impeller 29

G 05529 / Voith Turbo GmbH & Co. KG/ Huret la/ AWspOOIOO /13 January 1S97

is assigned a braking element, which is referred to here as a secondary impeller brake TB. This secondary impeller brake TB is fixed to the frame on a stationary gear part, preferably on the gear housing 32 indicated here.

In the case shown, the second mechanical transmission part 27 comprises, analogously to the transmission configuration shown in Figure 1, three planetary gear sets, a first planetary gear set PRI _1, a second planetary gear set PRM and a third planetary gear set PRIII. Regarding the structure and assignment of the

&iacgr;&ogr; individual switching elements are based on designs for mechanical

Gear part in Figure 1. This also applies analogously to the actuation and release of the individual switching elements assigned to the gear elements of the mechanical gear part 27. In this regard, reference can also be made to the explanations for the configuration according to Figure 1.

The functionality of the hydrodynamic transmission element can be described as follows:

In the first operating state, during the start-up process, the toroidal working chamber 30 is filled. The lock-up clutch ÜK is released. The secondary impeller clutch TK is actuated. The power flow or the transmission of power takes place via the transmission input shaft E ₁ , which can be coupled at least indirectly to a drive machine not shown here, the primary impeller 28, the secondary impeller 29 via the connecting shaft 31 to the second mechanical transmission part 27 and thus to the output shaft A.

The hydraulic transmission part 2 works as a hydrodynamic clutch during the starting process. Filling takes place during the individual &ogr; gear steps in the driving operating state essentially only during the

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp00100 / 13 January 1997

Starting process. In the transition to the second gear, the hydraulic transmission part 26, in particular the toroidal working chamber 30, is emptied. In the subsequent gears, the lock-up clutch ÜK is activated. This couples the transmission input shaft E with the mechanical transmission part 27, bypassing the hydraulic transmission part 26.

Depending on the actuation and release of the individual power shift devices, the speed and torque are converted in the mechanical transmission part 27.

&iacgr;&ogr; During braking, the paddle wheels change their function.

Secondary impeller 29 is held in place by the secondary impeller brake TB in relation to the stationary transmission parts and thus takes over the function of the stator impeller. The secondary impeller clutch TK is released. The lock-up clutch UK remains actuated and the primary impeller 28 is driven in the same direction of rotation as during the start-up process from the output side, in particular the transmission output shaft A, in accordance with the stages switched in the mechanical transmission part. The mechanical gear stages remain engaged.

If the individual impellers are blading at an angle, the individual blades are arranged so as to be inclined in the direction of the blade base that both in coupling operation during the first operating state and in braking operation, i.e. in the second operating state, the hydraulic transmission part 26 works in a spiking manner with the flow direction of the operating medium remaining constant in the toroidal working space.

Figure 7a shows a simplified schematic representation of another figuration of a gear designed according to the invention for generating the braking torque according to the first basic variant. The main differences compared to the gear structure shown in Figure 1 are the

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp00100/13 January 1997

Connection of the hydrodynamic clutch or the hydrodynamic retarder in the transmission, which is why only this connection option is shown in detail.

Figure 7a illustrates a transmission unit 40 comprising a first hydraulic transmission part 41 and a second mechanical transmission part 42. The transmission unit 40 further comprises a transmission input shaft E and a transmission output shaft A. The first hydraulic transmission part 41 comprises a hydrodynamic transmission element

&iacgr;&ogr; with at least two paddle wheels - a first paddle wheel and a

second impeller. The first impeller is referred to as the primary impeller 43, the second impeller as the secondary impeller 44. The primary impeller 43 and the secondary impeller 44 together form at least one toroidal working space 45. This can be filled with operating fluid. For this purpose, an operating fluid supply unit, not shown in detail here, is assigned to the toroidal working space 45. When the transmission designed according to the invention is used in a vehicle, the hydraulic transmission part 41 can be operated in two different operating states - a first operating state, which is referred to as driving, and a second operating state, which is referred to as braking, as a hydrodynamic clutch and as a hydrodynamic retarder. For this purpose, the individual impellers - the primary impeller 43 and the secondary impeller 44 - are each assigned different functions. During the first operating state, especially during the start-up process, the primary impeller 43 works as a so-called pump wheel and the secondary impeller 44 as a turbine wheel. In the second operating state, braking, the primary impeller 43 is assigned the function of the stator impeller of a hydrodynamic retarder. The secondary impeller 44 then takes over the function of the

&ogr; rotor blade wheel. To realize these functions,

Appropriate means should be provided to ensure functional allocation in

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp001 00 /13 January 19Ö7

in the manner mentioned. In terms of construction, the secondary impeller 44 can be coupled to the mechanical transmission part 42 in a rotationally fixed manner. The coupling is optionally carried out via two coupling devices, a first coupling device 46 and a second coupling device 47. The coupling device 46 enables the connection between the secondary impeller 44 and the mechanical transmission part 42 via a first connecting branch 48, the coupling device 47 enables the mechanical coupling between the secondary impeller 44 and the mechanical transmission part 42 via

&iacgr;&ogr; a second connection branch 49. Both connection branches can each

be coupled with the same gear element of the mechanical gear part 42 or with different gear elements of the mechanical gear part 42. The decisive factor here is the structure of the mechanical gear part. It is only necessary to ensure that the direction of rotation of the output can be reversed to achieve at least one reverse gear by actuating the clutch and brake elements in the mechanical gear part accordingly.

First means are provided by which the primary impeller can be connected to the transmission input shaft via 0 a partial range of the first operating state

can be coupled at least indirectly. The first means is a clutch device PK assigned to the primary impeller. Furthermore, second means are provided by means of which the transmission input shaft E can be coupled to the mechanical transmission part 42, bypassing the secondary impeller 44. The second means comprises a clutch device in the form of a lock-up clutch ÜK. The transmission unit also comprises third means which, in a second operating state, which is referred to as braking, holds and supports the primary impeller 43 against the stationary transmission parts. This third means is designed as a primary impeller brake PB.

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOO100/13 January 1997

The mechanical transmission part 42 can be designed in different ways. For example, it is conceivable that the mechanical transmission part 42 is designed in a similar way to that described in Figure 1. However, this is not absolutely necessary; in detail, different combinations of planetary gear sets and spur gear stages can be used.

The structural design according to Figure 7a makes it possible for both impellers - the primary impeller and the secondary impeller 44 - to be decoupled from the transmission input shaft E or the mechanical transmission part 42 in the mechanical driving range and thus to avoid any

Idling losses occur in this driving range.

Figure 7b shows an overview of the operating states achieved with the gearbox described in Figure 7a. This design represents a preferred version of the gearbox with regard to the connection of the hydraulic gearbox part 41.

The hydraulic transmission part 41 works as a hydrodynamic clutch during the start-up process. Filling takes place during the individual

0 gear position in operating state Driving preferably only during

Starting process. In this case, the primary impeller clutch PK is activated and the lock-up clutch ÜK between the transmission input shaft E and the mechanical transmission part 42 is released. The secondary impeller is in this case coupled via the first clutch element 46 to the mechanical transmission part via the connecting branch 48.

Preferably, the blading of the two impellers 43 and is inclined relative to the separation plane. The blade inclination is aligned in such a way that during the start-up process the primary impeller 43 and the secondary impeller 44 in spearing operation

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO /13 January 1997

·

·

work, i.e. the torque is transferred from the primary impeller 43 to the secondary impeller 44.

In the mechanical driving range, the hydrodynamic transmission element 41 is emptied, the lock-up clutch ÜK is engaged and thus connects the transmission input shaft E with the mechanical transmission part 42. The hydrodynamic transmission element 41 is completely bypassed in this case, which means that both impellers - the primary impeller 43 and the secondary impeller 44 - do not rotate and therefore no

Ventilation losses are to be expected. The individual gear stages are realized by activating and releasing the individual power shift elements in the mechanical transmission part 42.

The reverse gear is implemented by appropriately operating the individual power shift elements in the mechanical transmission part and is implemented primarily via the hydraulic drive element, i.e. the hydraulic transmission element 41. For this purpose, the primary impeller clutch PK is switched and the secondary impeller is coupled to the mechanical transmission part 42 via the second clutch device 47 via the connecting branch 49. In the simplest case, a connection between the secondary impeller 44 and a reversing gear in the mechanical transmission part 42 is implemented via the connecting branch 49. A corresponding operation of the individual power shift elements in the mechanical transmission part 42, which enable a reversal of the direction of rotation on the transmission output shaft, is also conceivable.

There are two possibilities for the braking process. However, the primary impeller 43 always takes over the function of the 0 stator impeller, in that it is

fixed and supported. To implement the functional change

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO / 13 January 1997

between power transmission and braking according to this basic variant, the following options are essentially conceivable. The secondary impeller 44 is either driven via the output, i.e. from the side of the transmission output shaft A with the same direction of rotation with a possible connection between the mechanical transmission part 42 and the transmission input shaft E or from the side of the output, i.e. the transmission output shaft A with the connection between the secondary impeller and the transmission input shaft released with the opposite direction of rotation relative to its direction of rotation during the start-up process.

&iacgr;&ogr; and takes over the function of the rotor blade wheel of a

hydrodynamic retarder. In this operating state, the hydraulic transmission part 41 is at least partially filled with operating fluid. This is circulated in the working space formed between the primary and secondary blade wheels due to the secondary blade wheel rotation and braked on the fixed blades of the primary blade wheel 43. To fix the primary blade wheel, means are provided which hold and support it in its position in a fixed manner relative to the round or fixed transmission parts. In this case, this means the actuation of the primary blade wheel brake PB. To implement the

0 first mentioned possibility, which in the peeling scheme does not show any precipitation

finds itself, the hydrodynamic transmission element 41 is filled to generate a braking torque and the secondary impeller 44 remains coupled to the transmission output shaft A via the engaged gear. Due to the overrun operation on the part of the output, the secondary impeller is driven by it, without changing the direction of rotation in relation to the direction of rotation during the start-up process. In this case, the clutch element 46 can be actuated for this purpose.

The first case can only be realized if the two impellers are blading at an angle. The inclination of the individual blades relative to the respective blade base is chosen in such a way that in the

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp00100 /13 January 1987

&diams; <

first operating state, i.e. in particular during the starting stage, the operating medium is diverted from the space between two adjacent blades of the primary impeller 43 driven by the transmission input shaft E due to its rotation at the blade rear sides of the secondary impeller 44, i.e. a closed operating medium circuit is formed between the primary and secondary impeller 43 and 44 and is then transmitted by torque. This mode of operation of the primary impeller in relation to the secondary impeller is referred to as spiking. Even in the braking operating state, the hydrodynamic transmission element 41 is connected to

&iacgr;&ogr; operating fluid. The engaged gear is indicated in the first

Possibility is retained in the mechanical transmission part 42. The primary impeller 43 is fixed and the secondary impeller 44 is driven in the same direction via the vehicle, in particular the transmission output shaft A. The two impellers thus exchange their functions. The secondary impeller is now driven in the same direction of rotation as the primary impeller during the starting stage. The primary impeller 43 is fixed and thus takes on the function of a stator of a hydrodynamic retarder. Due to the obliquely aligned blading, however, only part of the

0 rotation of the secondary impeller 44 generated flow energy of the

operating medium in the toroidal working space^ to generate a braking torque and thus be converted into heat. The operation of the secondary impeller 44 in this operating state can be described as fleeing compared to the primary impeller 43, which functions as a stator impeller. This type of realization of the generation of a braking torque by changing the function of the two impellers - primary and secondary impeller - can be carried out without additional effort from the engaged gear. However, since the braking torque generated is significantly lower than with a spiking

&ogr; mode of operation, an attempt is made to achieve a

spearing operation between the primary impeller 43 and the

G 05529 /Voith Turbo GmbH & Co. KG/ Kuret la/ AK/spOO100 /13 January 1(397 _m .. ....

Secondary impeller 44 to enable. In this case, the direction of rotation of the secondary impeller 44 is reversed compared to the direction of rotation during the start-up process, as indicated in the switching diagram. The reversal is preferably carried out by engaging a reverse gear. The driven secondary impeller 44 then converts the mechanical energy introduced into flow energy when the circuit is full, which is converted into heat energy at the stationary primary impeller 43. This preferred option for changing the function of the hydrodynamic transmission element 41 offers the advantage that by increasing the speed of the secondary impeller 44 and in conjunction with the high transmission capacity of the circuit parts resulting from the requirements of the hydrodynamic component during the start-up process, a large speed range is created which can be covered with one braking state, namely by changing the filling level. To implement the reversal of the direction of rotation, the secondary impeller 44 is also coupled to the mechanical transmission part 42 via the second connecting branch 49. Depending on the connection of the mechanical connecting branches 49 and 48 to the mechanical transmission part, it is possible to additionally use the lock-up clutch

0 ÜK activated. However, this is only possible in cases where the

During braking, connecting branch 48 still has the same direction of rotation as the transmission input shaft E. Otherwise, the bridging clutch ÜK must also be released.

However, the lock-up clutch is always released when both connecting branches are connected to the same gear element of the mechanical gear part 42, i.e. only one input into the mechanical gear part is available. In this case, as already explained, either by a reversing stage or the appropriate combination of the actuation of the clutch and brake elements contained in the mechanical gear part, a reversal of the direction of rotation at the output or the

G 05529 / Voith Turbo GmbH & Co. KG/Kuretla/AK/spOOlOO/13 January 1997 _# ..

Gearbox output, i.e. to realize a reverse gear. In braking mode, when the reverse gear is engaged, the connecting branches are driven in the opposite direction to the forward gears due to the overrun mode.

With regard to the individual braking stages in the braking operating state, reference can be made to the explanations of the gear configuration described in Figure 1. Here too, it is possible to obtain several braking stages depending on the design of the mechanical gear part 42.

Claims (36)

G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO / 13 January 1&THgr;&THgr;7 1. Gearbox assembly for drive units for realizing at least two operating states - a first operating state for power transmission with at least two gear shift stages and a second operating state for braking; 1.1 with a transmission input shaft and a transmission output shaft; 1.2 with a first hydraulic transmission part; 1.3 with a second mechanical transmission part; &iacgr;&ogr; 1.4 the two transmission parts are arranged in series; 1.5 the hydraulic transmission part comprises at least two impellers, a primary impeller and a secondary impeller, which together form at least one toroidal working space that can be filled with operating fluid, whereby the coupling of the two impellers to the transmission input shaft and the mechanical transmission part takes place at least over part of the first operating state in such a way that power is transmitted from the primary impeller via the secondary impeller to the mechanical transmission part; characterized by the following feature: 1.7 Means are provided which, in a second operating state, hold and support a first of the two impellers relative to the fixed gear parts and connect the other, second impeller to the second mechanical gear part. 2. Gear unit according to claim 1, characterized in that the first impeller is the primary impeller. 3. Gear unit according to claim 2, characterized by the following features: 0 3.1 the secondary impeller is rotationally fixed to the mechanical Gear part connectable; G 05529/Voith Turbo GmbH & Co. KG/ Kuret la/AK/spOOlOO /13 January 1SÖ7 3.2 first means are provided by means of which the primary impeller can be coupled at least indirectly to the transmission input shaft over a partial area of the first operating state; 3.3 Secondary means are provided by which the Secondary impeller can be coupled to the transmission input shaft; 3.4 further third means are provided which, in a second operating state, hold and support the primary impeller relative to the fixed gear parts. &iacgr;&ogr; 4. Gear unit according to one of claims 1 or 2, characterized by the features: 4.1 the secondary impeller can be connected to the mechanical transmission part in a rotationally fixed manner; 4.2 first means are provided by means of which the primary impeller can be coupled at least indirectly to the transmission input shaft over a partial area of the first operating state; 4.3 Second means are provided by means of which the transmission input shaft can be coupled to the mechanical transmission part, bypassing the secondary impeller; 4.4 further third means are provided which, in a second operating state of the primary impeller, hold and support it above the stationary transmission parts. 5. Gear unit according to one of claims 3 or 4, characterized in that the blading of the individual impellers is inclined relative to the separation plane formed by the primary and secondary impellers. 6. Gear unit according to one of claims 2 to 5, characterized in that further fourth means for enabling a Reversal of rotation of the secondary impeller in the second G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la / AK/spOOIOO /13 January 1997 Operating state opposite to its direction of rotation the starting state is provided. 7. Gear unit according to claim 6, characterized by the following features: 7.1 the mechanical transmission part comprises at least one transmission stage and one switchable reversing stage; 7.2 The fourth means are formed by the switching elements for connecting the inverter stage. 8. Gear unit according to claim 6, characterized by the following features: 8.1 the mechanical transmission part comprises at least one epicyclic gear; 8.2 The fourth means are formed by the powershift elements assigned to the individual transmission elements. 9. Transmission unit according to one of claims 2 to 8, characterized in that the first and/or second and/or third and/or fourth means are designed as power shift elements. 10. Transmission unit according to claim 9, characterized in that the power shift elements are formed in the form of clutch devices and/or brake devices, comprising at least two friction elements that can be pressed against one another. 11. Gear unit according to one of claims 2 to 10, characterized in that the first means is a clutch device assigned to the primary impeller. 0 12. Gear unit according to one of claims 2 to 11, characterized characterized in that the second means is a coupling device. G 05529 /Voith Turbo GmbH & Co. KG/ Kuret la / AK/sp00100 /13 January 1997 13. Transmission unit according to one of claims 2 to 12, characterized in that the third means comprises at least one braking device. 14. Gear unit according to claim 13, characterized by the following features: 14.1 the transmission unit comprises a housing enclosing the hydrodynamic and mechanical transmission parts; 14.2 The braking device rests on the housing. 15. Transmission unit according to one of claims 6 to 14, characterized in that the fourth means comprises clutch and/or braking devices which are suitably assigned to the individual components of the mechanical transmission part. 16. Gear unit according to one of claims 4 to 15, characterized in that the coupling of the secondary impeller with the mechanical gear part by means of two switchable clutch devices - a first clutch device and a 0 second coupling device - is feasible. 17. Gear unit according to claim 1, characterized in that the first impeller is the secondary impeller. 18. Gear unit according to claim 17, characterized by the following features: 18.1 the primary impeller can be connected to the gearbox input shaft in a rotationally fixed manner; 18.2 initial means are provided by which the The transmission input shaft can be coupled to the second mechanical transmission part; G 05528/Voith Turbo GmbH & Co. KG/Kuret la/AK/spOOIOO/13 January 1SI97 18.3 second means are provided by means of which the secondary impeller can be coupled to the connection between the gearbox input shaft and the mechanical transmission part; 18.4 further third means are provided which, in a second operating state, hold and support the secondary impeller relative to the fixed gear parts. 19. Gear unit according to one of claims 17 or 18, characterized in that the blading of the individual impellers β compared to the area formed by the primary and secondary impeller The parting plane is inclined. 20. Transmission unit according to one of claims 17 to 19, characterized in that the first and/or second and/or third means are designed as power shift elements. 21. Transmission unit according to claim 20, characterized in that the power shift elements are formed in the form of clutch devices and/or brake devices, comprising at least two friction elements that can be pressed against one another. 22. Transmission unit according to one of claims 18 to 21, characterized in that the first means is a clutch device provided between the transmission input shaft and the mechanical transmission part. 23. Transmission unit according to one of claims 18 to 22, characterized in that the second means is a clutch device. G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la/ AK/spOCHOO /13 January 1907 24. Gear unit according to one of claims 18 to 23, characterized in that the third means comprises at least one braking device associated with the secondary impeller. 25. Gear unit according to claim 24, characterized by the following features: 25.1 the transmission unit comprises a housing enclosing the hydrodynamic and mechanical transmission parts; 25.2 the braking device is supported on the housing. 26. Gear unit according to one of claims 1 to 25, characterized in that the mechanical gear part comprises at least one spur gear stage. 27. Gear unit according to one of claims 1 to 26, characterized in that the mechanical gear part comprises at least one planetary gear set with at least one ring gear, a sun gear, planetary gears and a carrier. 28. Gear unit according to claim 27, characterized by the following features:
28.1 the mechanical transmission part comprises at least three planetary gear sets coupled to one another - a first planetary gear set, a second planetary gear set and a third planetary gear set; 5 28.2 a first and a second transmission element of the first and second planetary gear set are connected to each other in a rotationally fixed manner; 28.3 the first transmission element of the first planetary gear set is additionally connected in a rotationally fixed manner to a first transmission element of the third planetary gear set; G 05529 / Voith Turbo GmbH & Co. KG/ Kuret la/ AK/spOOIOO /13 January 1&THgr;&THgr;7 28.4 a further third transmission element of the first planetary gear set can be coupled to the secondary impeller by means of a first coupling device; 28.5 the second transmission element of the first planetary gear set can be coupled to the secondary impeller by means of a second coupling device; 28.6 the second transmission element of the first planetary gear set can be locked by means of a first braking device; 28.7 a third transmission element of the second planetary gear set can be locked by means of a second braking device and a third transmission element of the third planetary gear set can be locked by means of a third braking device; 28.8 the second transmission element of the third planetary gear set is connected in a rotationally fixed manner to the transmission output shaft and by means of a third coupling element to the third transmission element of the third Planetary gear set can be coupled. 29. Gear unit according to claim 28, characterized by the following features: 29.1 the first gear element of the first planetary gear set is Sun wheel formed; _ 29.2 the second transmission element of the first planetary gear set is formed by the web; 29.3 The third transmission element of the first planetary gear set is formed by the ring gear. 30. Gear unit according to one of claims 28 or 29, characterized by the following features: 30.1 the first transmission element of the second planetary gear set is formed by the sun gear; G 05529 /Voith Turbo GmbH 4 Co. KG/ Kuret la/ AWspOOI OO /13. Januar 1887 _{&Lgr; tt} ,,,» 30.2 the second transmission element of the second planetary gear set is formed by the ring gear; 30.3 the third gear element of the second planetary gear set is formed by the web. 31. Gear unit according to one of claims 28 to 30, characterized by the following features: 31.1 the first transmission element of the third planetary gear set is driven by Sun wheel formed;
&iacgr;&ogr; 31.2 the second gear element of the third planetary gear set is driven by bridge formed;
31.3 The third transmission element of the third planetary gear set is formed by the ring gear. 32. Gear unit according to one of claims 1 to 31, characterized in that a damping element is connected upstream of the hydraulic gear element in the direction of force flow. 33. Gear unit according to claim 32, characterized by the following features: 33.1 the damping device is disc-shaped; 33.2 the damping device comprises a plurality of torque supports arranged on a specific diameter and spring devices arranged between them. 34. Gear unit according to one of claims 32 or 33, characterized in that the damping device is arranged in a region which is formed by the outer circumference of the primary impeller and the arrangement of the primary impeller clutch. is 0. G 05529 / 297 OO 605.3 / Voith Turbo Gnity & Ca.'kG / !Kuril &UAK/gwä>02& / 18*June 1&THgr;97 35. Hydrodynamic unit for installation in a drive train between a driving shaft and a driven shaft 35.1 with at least two impellers - a primary impeller and a secondary impeller - which together form at least one toroidal working space; 35.2 with a casing enclosing the two impellers; characterised by the following features: 35.3 one of the first two impellers - primary impeller or secondary impeller - shall have at least one switching element for selectively &iacgr;&ogr; coupling and decoupling assigned to the driving shaft; 35.4 the first impeller is assigned at least one device for securing and supporting the impeller, which can be fastened to the housing. 36. Hydrodynamic assembly according to claim 35, characterized in that the blading of the primary and secondary impeller runs inclined with respect to a separation plane formed between the primary and secondary impeller.