DE102008041210A1 - Multi-stage gearbox, particularly automatic gearbox for motor vehicle, comprises four planetary gear sets, which are arranged in housing, where eight rotating shafts includes two drive shafts - Google Patents

Abstract

The multi-stage gearbox comprises four planetary gear sets (P1,P2,P3,P4), which are arranged in a housing (G). Eight rotating shafts (1 to 8) including two drive shafts and six switching elements (05,48,17,68) including brakes and clutches are provided with the gearbox. The selective engagement effects and different transmission ratio between the drive shafts are such provided that nine forward gears and a backward gear are realized. A sun wheel of the planetary gear train is connected with the fourth shaft.

Description

The The present invention relates to a planetary multi-speed transmission, in particular an automatic transmission for a motor vehicle, according to the preamble of claim 1.

Automatic transmission, in particular for motor vehicles, include the state the technology planetary gear sets, by means of friction or switching elements, such as clutches and brakes, are switched and usually with a slip action and optionally with a startup element provided with a lockup clutch, such as a hydrodynamic torque converter or a fluid coupling, are connected.

Such automatic transmissions are for example from the DE 199 49 507 A1 the applicant a multistage transmission known in which two non-shiftable Vorschaltradsätze are provided on the drive shaft, the output side produce two speeds that are selectively switchable in addition to the speed of the drive shaft to a force acting on the output shaft, switchable Doppelplanetenradsatz by selectively closing the switching elements used, that only one switching element must be switched on or off for switching from one gear to the next higher or lower gear of the two currently operated switching elements. Using five shift elements, seven forward gears are achieved, nine or ten forward gears using six shift elements.

Furthermore, from the DE 10213 820 A1 a multi-speed automatic transmission with eight forward gears and a reverse gear is known, comprising a first input path T1 of a first gear ratio; an input path T2 having a larger gear ratio than this input path T1; a Ravigneaux type four-element planetary gear set, the four elements being a first element, a second element, a third element and a fourth element in the order of the elements in a speed diagram; a clutch C-2 which transmits rotation of the input path T2 to the first element S3; a clutch C-1 which transmits the rotation from the input path T2 to the fourth element S2; a clutch C-4 which transmits a rotation from the input path T1 to the first element; a clutch C-3 which transmits the rotation from the input path T1 to the second element C3; a brake B-1 which establishes the engagement of the fourth element; a brake B-2 which makes the engagement of the second member; and an output element coupled to the third element S3.

A 9-speed multi-speed transmission is also from the DE 29 36 969 A1 known; it comprises eight shift elements and four sets of wheels, one wheel set serving as a primary gear and the main gear having a Simpson set and a wertere serving as a reverse gear wheelset.

Further multi-speed transmissions are for example from the DE 10 2005 010 210 A1 and the DE 10 2006 006 637 A1 the applicant known.

Automatically switchable vehicle transmissions in planetary construction are in general already described many times in the prior art and subject to a permanent development and improvement. So should this Gear a low construction cost, especially a small number require switching elements and in sequential switching double circuits avoid, so that in circuits in defined gear groups each only a switching element is changed.

From the not yet published DE 10 2008 000 428.3 The applicant is a planetary gear multi-speed transmission known which has a drive and an output, which are arranged in a housing. In the known transmission at least four planetary gear sets, hereinafter referred to as the first, second, third and fourth planetary gear set, at least eight rotatable shafts - hereinafter referred to as drive shaft, output shaft, third, fourth, fifth, sixth, seventh and eighth shaft - and at least six switching elements, comprising brakes and clutches, provided, the selective engagement causes different ratios between the drive and the output, so that preferably nine forward gears and one reverse gear can be realized.

in this connection form the first and the second planetary set, preferably as Negative planetary gear trains are formed, a switchable Vorschaltradsatz, wherein the third and the fourth planetary gear set a Make main gear.

In the known multi-speed transmission is provided that the webs of the first and second planetary gear sets are coupled to each other via the fourth shaft, which is connected to an element of the main gearset that the ring gear of the first planetary gear set coupled to the sun gear of the second planetary gear set on the eighth wave is, which is releasably connectable via a first clutch to the drive shaft and that the sun gear of the first planetary gear by means of the third shaft via a first brake to a housing of the transmission is coupled and releasably connectable via a second clutch to the drive shaft, wherein the ring gear of second planetary gear set by means of the fifth shaft via a second brake to a housing the transmission can be coupled. In addition, the seventh shaft with at least one element of the main gearset is constantly connected and coupled via a third brake to a housing of the transmission, the sixth shaft is continuously connected to at least one werteren element of the main gear and releasably connected via a third clutch to the drive shaft; the output shaft is permanently connected to at least one further element of the main gearset.

Preferably is the fourth wave constantly in the known transmission connected to the ring gear of the third planetary gear set, wherein the sixth wave constantly with the ring gear of the fourth planetary gear set and connected to the bridge of the third planetary gear set and over the third clutch releasably connectable to the drive shaft is. Furthermore, the seventh wave is constantly with the sun gears connected to the third and fourth planetary gear set and over the third brake can be coupled to a housing of the transmission. The output takes place here via the constantly with the output of the fourth planetary gear set output shaft. Of The third and fourth planetary gear sets can be upgraded to a Ravigneaux set with common bridge and common ring gear be composed or reduced.

Of the present invention is based on the object, a multi-step transmission to propose the type mentioned, which at least nine Forward gears and at least one reverse gear having sufficient translation, in which the construction cost and the size, in particular the overall length, or the weight be optimized and also the efficiency in terms the drag and gearing losses is improved. In addition, should small in the multistage transmission according to the invention Support moments act on the switching elements. Especially should the transmission according to the invention for be suitable for a front-transverse construction.

These The object is achieved by the features of claim 1. Further advantages and advantageous Embodiments will become apparent from the dependent claims.

Therefore is a multi-stage transmission according to the invention proposed in planetary design, which has a drive and a Downlift, which are arranged in a housing. Of further are at least four planetary gear sets, below referred to as first, second, third and fourth planetary gear set, the second planetary set preferably as plus planetary gear set is executed and the other planetary gear sets as minus - planetary gear sets executed are at least eight rotatable shafts - hereinafter referred to as Drive shaft, output shaft, third, fourth, fifth, sixth, seventh and eighth wave - as well as at least six Switching elements, comprising brakes and clutches, provided, whose selective intervention different gear ratios between the drive and the output causes, so preferably nine forward gears and one reverse gear is feasible.

One simple minus planetary set includes known a sun gear, a ring gear and a bridge on which planet gears rotatable are stored, each combing with sun gear and ring gear. As a result, the ring gear at festhaltem web one to the sun gear opposite direction of rotation. In contrast, includes a simple plus planetary gearset a sun gear, a ring gear and a Bridge on the inner and outer planetary gears are rotatably mounted, with all inner planetary gears with the sun gear and all outer planet gears mesh with the ring gear, with each inner planetary gear meshes with an outer planetary gear. As a result, the ring gear at the fixed web the same Direction of rotation as the sun gear.

According to the Invention is provided that the sun gear of the first planetary gear set connected to the fourth shaft, which is connected to the sun gear of the fourth Planet set connected and via a first brake on a housing of the transmission can be coupled, wherein the eighth Shaft connected to the bridge of the first planetary gear set and over a first clutch is detachably connectable to the sixth shaft, which is connected to a component which the ring gear of fourth planetary gear set and the sun gear of the third planetary gear set connects with each other.

in this connection is the ring gear of the first planetary gear set with the drive shaft connected via a second clutch with the seventh Wave is detachably connectable, with the seventh wave with the bridge of the third planetary gear set and the bridge of the second planetary gear set is connected and wherein the web of the fourth planetary gear set with the third wave is connected, which has a second Brake can be coupled to a housing of the transmission.

Of another is the sun gear of the second planetary gear set with the fifth Connected by a third brake to a housing the transmission can be coupled, wherein the output shaft with the ring gear of the second planetary gearset and the ring gear of the third planetary gearset is connected and wherein a third clutch is provided, which the eighth shaft with the drive shaft or the fourth shaft with the eighth wave releasably connects.

In a further development of the invention, the second planetary gear set and the third Pla set of items to a Ravigneaux set with common bridge and common ring gear summarized or reduced.

By the inventive design of the multi-speed transmission arise especially for passenger cars suitable translations and a considerable increase in the overall spread of the multistage transmission, resulting in an improvement in ride comfort and a significant reduction in fuel consumption be effected.

About that In addition, with the multistage transmission according to the invention by a small number of switching elements, the construction cost significantly reduced. Advantageously, it is with the invention Multi-step transmission possible, a start with a hydrodynamic Converter, an external starting clutch or other suitable to perform external starting elements. It is also conceivable a starting process with a built-in gear start-up element to enable. Preferably, a switching element is suitable, which in the first forward and reverse is pressed.

Of further results in the inventive Multi-step transmission a good efficiency in the main gears with regard to drag and gear losses.

Further There are small moments in the switching elements and in the planetary gear sets of the multi-speed transmission, whereby the wear at the multi-stage transmission is reduced in an advantageous manner. moreover is due to the low moments a correspondingly small dimensions allows, whereby the required space and the corresponding costs are reduced. Beyond that also low speeds at the shafts, the switching elements and the planetary gear sets.

Furthermore is the transmission according to the invention designed in such a way that an adaptability to different powertrain configurations both in the direction of force flow as well as in space is possible.

The Invention will be described below with reference to the accompanying figures exemplified in more detail. In these places represents:

1 : A schematic view of a preferred embodiment of a multi-speed transmission according to the invention;

2 : An exemplary circuit diagram for a multi-step transmission according to 1 ;

3 : A diagram for illustrating the incremental phi corresponding to the respective gear ratio i of a gear for the in 1 shown gears;

4 : A diagram to illustrate the corresponding gear for each degree of efficiency for the in 1 shown gears; and

5 : A schematic view of another preferred embodiment of a multi-speed transmission according to the invention.

In 1 is an inventive multi-stage transmission with a drive shaft 1 , an output shaft 2 and four planetary gear sets P1, P2, P3 and P4, which are arranged in a housing G, wherein the planetary gear sets P1, P3 and P4 are formed as minus planetary gear sets and the planetary gear set P2 is designed as a plus-planetary gearset.

At the in 1 shown embodiment, which is particularly suitable for a front-transverse construction, the third and the fourth planetary gear set P3, P4 axially arranged in the same Radsatzebene arranged, the third planetary gear set P3 is radially disposed over the fourth planetary gear set P4, whereby The total of four planetary gear sets considered advantageous spatially axially limited to three Radsatzebenen. Here, the ring gear of the fourth planetary gear set P4 is connected via a component with the sun gear of the third planetary gear set P3. Axially considered in this case, the planetary gear sets in the order P2, P4 / P3, P1 are arranged ie the radially superposed planetary gear sets P4 / P3 are axially disposed between the first and second planetary gear set P1, P2.

Of further, the third planetary set P3 and the second Planet set P2 to a Ravigneaux set with common bridge and combined and reduced common ring gear; alternative For example, the second planetary set P2 and the third planetary set P3 be designed as separate wheelsets.

How out 1 can be seen, six switching elements, namely three brakes 03 . 04 . 05 and three couplings 48 . 17 and 68 intended. The spatial arrangement of the switching elements can be arbitrary and is limited only by the dimensions and the external shape.

With these switching elements a selective switching of nine forward gears and one reverse gear can be realized. The multistage transmission according to the invention has a total of eight rotatable shafts, namely the worlds 1 . 2 . 3 . 4 . 5 . 6 . 7 and 8th wherein the drive shaft forms the first shaft and the output shaft forms the second shaft of the transmission.

According to the invention in the multi-stage transmission according to 1 provided that the sun gear of the first planetary gear set P1 with the fourth wave 4 connected to the sun gear of the fourth planetary gear set P4 and a first brake 04 can be coupled to the housing G of the transmission and a first clutch 48 with the eighth wave 8th is releasably connectable, which is connected to the web of the first planetary gear set P1 and a second clutch 68 with the sixth wave 6 is detachably connectable, which is connected to the component which connects the ring gear of the fourth planetary gear set P4 and the sun gear of the third planetary gear set P3 together. Furthermore, the ring gear of the first planetary gear set P1 with the drive shaft 1 connected via a second clutch 17 with the seventh wave 7 is detachably connectable, wherein the seventh wave 7 is connected to the web of the third planetary gear set P3 and the web of the second planetary gear set P2.

Furthermore, the bridge of the fourth planetary set P4 is the third time 3 connected, which via a second brake 03 can be coupled to the housing G of the transmission, wherein the sun gear of the second planetary gear set P2 with the fifth shaft 5 connected via a third brake 05 can be coupled to the housing G of the transmission and wherein the output shaft 2 is connected to the ring gear of the second planetary gear set P2 and the ring gear of the third planetary gear set P3.

In the event that the third planetary gear set P3 and the second planetary gear set P2 form a Ravigneaux set, the output shaft is 2 with the common ring gear and the seventh shaft 7 connected to the common bridge of the Ravigneaux theorem, as shown 1 illustrated.

Here is the second clutch 17 viewed radially above the first planetary gearset P1; the first clutch 68 is arranged between the first planetary gear P1 and the radially stacked planetary gear sets P3 / P4. Preferably, the third clutch 48 viewed radially below the first clutch 68 arranged.

As part of a development of the invention, the third clutch 48 through another third clutch 18 to be replaced, which is the eighth wave 8th with the drive shaft 1 releasably connects.

In 2 is an exemplary circuit diagram of a multi-speed transmission according to 1 shown. For each gear three switching elements are closed. The shift scheme, the respective ratios of the individual gear ratios i and the step to be determined therefrom or increments phi are taken to the next higher gear example, the value of 9.88 represents the spread of the transmission.

Typical values for the stationary ratios of the planetary gear sets P1, P2, P3 and P4 are respectively -2.00, 3.50, -1.60 and -2.00. Out 2 It can be seen that in sequential switching double circuits or group scarf lines are avoided, since two adjacent grades use two switching elements together. Further, it will be seen that a large spread is achieved with small gear jumps. Furthermore, with the in 1 a total of nine forward gears and a reverse gear can be realized.

The third brake 05 and / or the first clutch 68 are preferably designed as claw switching elements. As a result, the drag torques of the transmission, which arise due to the small distance between the friction surfaces of a Reibschaltelementes in the open state and the oil contained therein or air-oil mixture is reduced. The clutches remaining 18 . 48 . 17 and the rest of the brakes 03 . 04 are preferably designed as Reibschaltelemente or lamellar switching elements.

The first forward gear is obtained by closing the first clutch 68 and the second and third brakes 03 . 05 , the second forward gear by closing the first and third brakes 04 . 05 and the first clutch 68 , the third forward gear by closing the third and first clutch 48 . 68 and the third brake 05 , the fourth forward gear by closing the first and second clutches 68 . 17 and the third brake 05 , the fifth forward gear by closing the third, first and second clutches 48 . 68 . 17 , the sixth forward gear by closing the first brake 04 and the first and second clutches 68 . 17 , the seventh forward gear by closing the second brake 03 and the first and second clutches 68 . 17 , the eighth forward gear by closing the second and first brakes 03 . 04 and the second clutch 17 and the ninth forward gear by closing the second brake 03 and the third and second clutches 48 . 17 , Reverse is achieved by closing the second and third brakes 03 . 05 and the third clutch 48 ,

Characterized in that in the first forward and reverse, the second and the third brake 03 . 05 are closed, these switching elements (designed as Reibschaltelemente or lamellae switching elements) can be used as starting elements.

According to the invention, even with the same transmission scheme depending on the switching logic under give different gear steps, so that an application or vehicle-specific variation is possible.

A diagram for the illustration of the respective ratio i in a gear corresponding incremental phi for the in 1 shown gearbox according to the in 2 shown values is the subject of 3 ,

Furthermore, the relationship between the efficiency eta and the respective gear of a transmission according to the invention according to 1 based 4 illustrated. Out 4 It can be seen that in the formation of the planetary gear sets P2 and P3 as Ravigneaux set the efficiency in the first three gears improved.

This in 5 embodiment shown differs from the embodiment according to 1 in that the first planetary gear set P1 is arranged axially between the planetary gear sets P4 / P3 arranged radially one above the other and the second planetary gearset P2, wherein the third clutch 48 by the third clutch, which is preferably designed as a friction clutch 18 which is the eighth wave 8th with the drive shaft 1 releasably connects.

Here is the third brake 05 arranged on the side of the second planetary gear set P2, which is opposite to the radially superposed planetary gear sets P3 / P4. The second clutch 17 is in front of the second planetary set P2 in the direction of flow of power, but spatially on the side of the third planetary set P3, which is opposite to the second planetary set P2, for example at least partially in a region radially above the first planetary set P1.

Furthermore, the third clutch 18 considered radially below the first brake preferably 04 arranged. Further, the first clutch 68 viewed axially between the first planetary gear set P1 and the radially superposed planetary gear sets P3 / P4 arranged.

That of the embodiment according to 5 corresponding circuit diagram corresponds to that in 2 Scheme shown with the difference that the clutch 48 through the clutch 18 is replaced.

According to the invention it possible, at any suitable point of the multi-speed transmission provide additional freewheels, for example between a shaft and the housing or around two shafts, if necessary connect to.

On the drive side or on the output side can according to the invention a Axle differential and / or a distribution differential can be arranged.

In the context of an advantageous development, the drive shaft 1 be separated by a coupling element of a drive motor as needed, with a hydrodynamic converter, a hydraulic clutch, a dry starting clutch, a wet starting clutch, a magnetic powder clutch or a centrifugal clutch can be used as a coupling element. It is also possible to arrange such a starting element in the power flow direction behind the transmission, in which case the drive shaft 1 constantly connected to the crankshaft of the engine.

The inventive multi-speed transmission allows also the arrangement of a torsional vibration damper between engine and transmission.

In the context of a further, not shown embodiment of the invention can on each shaft, preferably on the drive shaft 1 or the output shaft 2 , a wear-free brake, such. As a hydraulic or electrical retarder or the like, be arranged, which is particularly important for use in commercial vehicles of particular importance. Furthermore, to drive additional units on each shaft, preferably on the drive shaft 1 or the output shaft 2 be provided a power take-off.

The used Reibschaltelemente can be used as a load-switching Be formed clutches or brakes. In particular, you can non-positive clutches or brakes, such. B. multi-plate clutches, Band brakes and / or cone clutches are used.

One Another advantage of the presented here multistage transmission consists then that on each wave as a generator and / or as an additional Drive machine is an electric machine attachable.

Of course Every constructive training, especially every one, also falls spatial arrangement of the planetary gear sets and the Switching elements in themselves and to each other and as far as technically reasonable, under the scope of the present claims without the function of the transmission as stated in the claims to influence, even if these training courses are not explicitly in the figures or in the description are shown.

1

first Shaft, drive shaft

2

second Shaft, output shaft

3

third wave

4

fourth wave

5

fifth wave

6

sixth wave

7

seventh wave

8th

eighth wave

03

second brake

04

first brake

05

third brake

48

third clutch

17

second clutch

18

third clutch

68

first clutch

P1

first planetary set

P2

second planetary set

P3

third planetary set

P4

fourth planetary set

i

translation

phi

increment

G

casing

eta

efficiency

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19949507 A1 [0003]
• DE 10213820 A1 [0004]
• - DE 2936969 A1 [0005]
• - DE 102005010210 A1 [0006]
• - DE 102006006637 A1 [0006]
• - DE 102008000428 [0008]

Claims (16)

Multi-stage transmission in planetary construction, in particular automatic transmission for a motor vehicle, comprising a drive shaft ( 1 ), an output shaft ( 2 ) and four planetary gear sets (P1, P2, P3, P4), which are arranged in a housing (G), a total of at least eight rotatable shafts ( 1 . 2 . 3 . 4 . 5 . 6 . 7 . 8th ) as well as six switching elements ( 03 . 04 . 05 . 48 . 17 . 18 . 68 ), comprising brakes ( 03 . 04 . 05 ) and couplings ( 48 . 17 . 18 . 68 ), whose selective engagement different transmission ratios between the drive shaft ( 1 ) and the output shaft ( 2 ), so that nine forward gears and one reverse gear are feasible, wherein the sun gear of the first planetary gear set (P1) with the fourth wave ( 4 ) connected to the sun gear of the fourth planetary gearset (P4) and via a first brake ( 04 ) is connectable to the housing (G) of the transmission, wherein the eighth shaft ( 8th ) connected to the web of the first planetary gear set (P1) and via a first clutch ( 68 ) with the sixth wave ( 6 ) is releasably connectable, which is connected to the component, which connects the ring gear of the fourth planetary gear set (P4) and the sun gear of the third planetary gear set (P3), wherein the ring gear of the first planetary gear set (P1) with the drive shaft ( 1 ) connected via a second clutch ( 17 ) with the seventh wave ( 7 ) is detachably connectable, wherein the seventh wave ( 7 ) is connected to the web of the drift planetary gear set (P3) and the web of the second planetary gear set (P2), wherein the web of the fourth planetary gear set (P4) with the third wave ( 3 ) connected via a second brake ( 03 ) is coupled to the housing (G) of the transmission, wherein the sun gear of the second planetary gear set (P2) with the fifth wave ( 5 ) connected via a third brake ( 05 ) is connectable to the housing (G) of the transmission, wherein the output shaft ( 2 ) is connected to the ring gear of the second planetary gear set (P2) and the ring gear of the third planetary gear set (P3) and wherein a further, third clutch ( 18 . 48 ), which is the eighth time ( 8th ) with the drive shaft ( 1 ) or the fourth wave ( 4 ) with the eighth wave ( 8th ) releasably connects. Multi-step transmission according to Claim 1, characterized that the first, third and fourth planetary gear set (P1, P3, P4) as Minus planetary gear sets are formed, wherein the second Planet set (P2) is designed as a plus-planetary gear set. Multi-step transmission according to claim 1 or 2, characterized characterized in that the third and the fourth planetary gear set (P3, P4) are arranged axially in the same Radsatzebene, wherein the third planetary set (P3) viewed radially over the fourth planetary set (P4) is arranged, whereby the total four planetary gear sets (P1, P2, P3, P4) spatially axial limited to three Radsatzebenen. Multi-stage transmission according to claim 1, 2 or 3, characterized in that the third planetary gear set (P3) and the second planetary gear set (P2) form a Ravigneaux set with common web and common ring gear, wherein the output shaft ( 2 ) with the common ring gear and the seventh shaft ( 7 ) is connected to the common bridge of the Ravigneaux theorem. Multi-step transmission according to one of the preceding claims, characterized in that the radially arranged one above the other Planet sets (P4 / P3) viewed axially between the second Planet set (P2) and the first planetary gear set (P1) are arranged. Multi-step transmission according to claim 5, characterized in that the second clutch ( 17 ) viewed radially above the first planetary gear set (P1) is arranged. Multi-step transmission according to claim 5 or 6, characterized in that the first clutch ( 68 ) is arranged axially between the first planetary gear set (P1) and the radially superposed planetary gear sets (P3 / P4). Multi-step transmission according to claim 5, 6 or 7, characterized in that the third clutch ( 48 ) viewed radially below the first clutch ( 68 ) is arranged. Multi-step transmission according to Claim 1, 2, 3 or 4, characterized in that the first planetary gear set (P1) viewed axially between the second planetary gear set (P2) and arranged radially one above the other Planet sets (P3 / P4) is arranged. Multi-step transmission according to claim 9, characterized in that the third brake ( 05 ) is arranged on the side of the second planetary gear set (P2), which is opposite to the radially superposed planetary gear sets (P3 / P4). Multi-step transmission according to claim 9 or 10, characterized in that the second clutch ( 17 ) is arranged on the side of the third planetary gear set (P3), which is opposite to the second planetary gear set (P2). Multi-step transmission according to claim 9, 10 or 11, characterized in that the third clutch ( 18 ) viewed radially below the first brake ( 04 ) is arranged. Multi-step transmission according to claim 9, 10, 11 or 12, characterized in that the first Clutch ( 68 ) Axially considered between tween the first planetary gear set (P1) and the radially superposed planetary gear sets (P3 / P4) is arranged. Multi-step transmission according to one of the preceding claims, characterized in that the third brake ( 05 ) and / or the first clutch ( 68 ) are designed as claw switching elements, wherein the remaining clutches ( 48 . 17 . 18 ) and the other brakes ( 03 . 04 ) are designed as Reibschaltelemente. Multi-step transmission according to one of the preceding claims, characterized in that the first forward gear by closing the first clutch ( 68 ) and the second and third brake ( 03 . 05 ), the second forward gear by closing the first and third brakes ( 04 . 05 ) and the first clutch ( 68 ), the third forward gear by closing the third and first clutch ( 48 respectively. 18 . 68 ) and the third brake ( 05 ), the fourth forecast gear by closing the first and the second clutch ( 68 . 17 ) and the third brake ( 05 ), the fifth forward gear by closing the third, first and second clutch ( 48 respectively. 18 . 68 . 17 ), the sixth forward gear by closing the first brake ( 04 ) and the first and second clutches ( 68 . 17 ), the seventh forward gear by closing the second brake ( 03 ) and the first and second clutches ( 68 . 17 ), the eighth forward gear by closing the second and first brake ( 03 . 04 ) and the second clutch ( 17 ) and the ninth forward gear by closing the second brake ( 03 ) and the third and second clutch ( 48 respectively. 18 . 17 ) and that the reverse gear by closing the second and third brake ( 03 . 05 ) and the third clutch ( 48 respectively. 18 ). Multi-step transmission according to one of the preceding claims, characterized in that starting by means of the second or the third brake ( 03 . 05 ) of the transmission takes place.