DE102008041210B4 - Multi-speed transmission - Google Patents

Abstract

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 eight rotatable shafts ( 1, 2, 3, 4, 5, 6, 7, 8) and six switching elements (03, 04, 05, 48, 17, 18, 68), comprising brakes (03, 04, 05) and couplings (48, 17 , 18, 68) whose selective engagement causes different ratios between the drive shaft (1) and the output shaft (2), so that nine forward gears and one reverse gear can be realized, wherein the sun gear of the first planetary gear set (P1) with the fourth shaft (4 ), which is connected to the sun gear of the fourth planetary gear set (P4) and can be coupled to the housing (G) of the gearbox via a first brake (04), the eighth shaft (8) being connected to the web of the first planetary gear set (P1). connected via a first coupling (68) with the sixth shaft ( 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) connected to the drive shaft (1) is, via a second clutch (17) releasably connectable to the seventh shaft (7), wherein the seventh shaft (7) with the web of the third planetary gear set (P3) and the web of the second planetary gear set (P2) is connected, the web of the fourth planetary gearset (P4) is connected to the third shaft (3) which can be coupled to the housing (G) of the transmission via a second brake (03), wherein the sun gear of the second planetary gearset (P2) is connected to the fifth shaft (5) is connected, which via a third brake (05) to the housing (G) of the transmission is coupled, wherein the output shaft (2) connected to the ring gear of the second planetary gear set (P2) and the ring gear of the third planetary gear set (P3) is and where a third clutch (18, 48) is provided, which the eighth shaft (8) releasably connects to the drive shaft (1) or the fourth shaft (4) to the eighth shaft (8).

Description

The present invention relates to a multi-stage planetary gear, in particular an automatic transmission for a motor vehicle.

Automatic transmissions, in particular for motor vehicles, comprise in the prior art planetary gear sets which are switched by means of friction elements such as clutches and brakes, and usually with a slipping action and optionally with a lock-up starting element, such as a hydrodynamic torque converter or a fluid coupling 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 102 13 820 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 serves as a Vorschaltgetriebe and the main gear has a Simpson set and another 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 in general are already widely described in the prior art and are subject to permanent development and improvement. So these transmissions require a low construction cost, in particular a small number of switching elements and avoid sequential switching double circuits, so that in circuits in defined gear groups only one switching element is changed.

From the not pre-published DE 10 2008 000 428 A1 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.

Here, the first and the second planetary gear set, which are preferably designed as minus planetary gear sets, form a switchable transfer gearset, wherein the third and the fourth planetary gear set form a main gearset.

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 further 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, in the known transmission, the fourth shaft is constantly connected to the ring gear of the third planetary gear set, wherein the sixth shaft is constantly connected to the ring gear of the fourth planetary gear set and the web of the third planetary gear set and releasably connectable via the third clutch to the drive shaft. Further, the seventh shaft is constantly connected to the sun gears of the third and fourth planetary gear set and can be coupled via the third brake to a housing of the transmission. The output takes place here via the output shaft permanently connected to the web of the fourth planetary gearset. Furthermore, the third and the fourth planetary gear set can be combined or reduced to form a Ravigneaux set with common web and common ring gear.

The present invention has for its object to provide a multi-speed transmission of the type mentioned, which has at least nine forward gears and at least one reverse gear with sufficient translation, in which the construction cost and size, in particular the overall length, and the weight are optimized and also the Efficiency is improved in terms of drag and gearing losses. In addition, in the multistage transmission according to the invention, small supporting moments act on the shifting elements. In particular, the transmission according to the invention should be suitable for a front-transverse construction.

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

Accordingly, a multi-speed transmission according to the invention is proposed planetary design, which has a drive and an output, which are arranged in a housing. Furthermore, four planetary gear sets, hereinafter referred to as the first, second, third and fourth planetary gear set, wherein the second planetary gear set is preferably designed as plus planetary gear set and the other planetary gear sets are negative - planetary gear sets, eight rotatable shafts - hereinafter referred to as drive shaft, Output shaft, third, fourth, fifth, sixth, seventh and eighth shaft - and six switching elements, including brakes and clutches, provided whose selective engagement causes different ratios between the drive and the output, so that nine forward gears and one reverse gear can be realized.

A simple minus planetary set includes known a sun gear, a ring gear and a bridge on which planet gears are rotatably mounted, each meshing with the sun gear and ring gear. In this way, the ring gear at a fixed web on a sun gear opposite direction of rotation. In contrast, a simple plus-planetary gearset comprises a sun gear, a ring gear and a web on which inner and outer planetary gears are rotatably mounted, wherein all inner planetary gears mesh with the sun gear and all outer planetary gears with the ring gear, each inner planetary gear each having an outer Planet wheel meshes. As a result, the ring gear has the same direction of rotation when holding the web as the sun gear.

According to the invention it is provided that the sun gear of the first planetary gear set is connected to the fourth shaft, which is connected to the sun gear of the fourth planetary gear set and can be coupled via a first brake to a housing of the transmission, wherein the eighth wave with the web of the first planetary gearset connected and releasably connectable via a first clutch with the sixth shaft, which is connected to a component which connects the ring gear of the fourth planetary gear set and the sun gear of the third planetary gearset together.

Here, the ring gear of the first planetary gear set is connected to the drive shaft, which is releasably connectable via a second clutch with the seventh shaft, wherein the seventh shaft is connected to the web of the third planetary gear set and the web of the second planetary gear set and wherein the web of the fourth planetary gearset is connected to the third shaft, which can be coupled via a second brake to a housing of the transmission.

Furthermore, the sun gear of the second planetary gear set is connected to the fifth shaft, which is coupled via a third brake to a housing of the transmission, wherein the output shaft is connected to the ring gear of the second planetary gear set and the ring gear of the third planetary gear set and wherein a third clutch provided which removably connects the eighth shaft to the drive shaft or the fourth shaft to the eighth shaft.

Within the scope of a development of the invention, the second planetary gearset and the third planetary gearset are associated with a Ravigneaux set common web and common ring gear summarized or reduced.

The inventive design of the multi-speed transmission results in particular for passenger cars suitable translations and a significant increase in the overall spread of the multi-speed transmission, whereby an improvement in ride comfort and a significant consumption reduction can be effected.

In addition, the construction cost is considerably reduced with the multi-stage transmission according to the invention by a small number of switching elements. Advantageously, it is possible with the multistage transmission according to the invention to carry out a start with a hydrodynamic converter, an external starting clutch or other suitable external starting elements. It is also conceivable to allow a starting operation with a start-up element integrated in the transmission. Preferably, a switching element which is actuated in the first forward gear and in reverse is suitable.

Furthermore, in the multistage transmission according to the invention a good efficiency in the main gears with respect to the drag and gear losses.

Furthermore, there are small moments in the switching elements and in the planetary gear sets of the multi-speed transmission, whereby the wear in the multi-speed transmission is advantageously reduced. In addition, a correspondingly small dimensions are made possible by the low moments, whereby the required space and the corresponding costs are reduced. In addition, there are also low speeds in the waves, the switching elements and the planetary gear sets.

In addition, the transmission according to the invention is designed such that an adaptability to different drive train configurations is made possible both in the power flow direction as well as in space.

• 1: Eine schematische Ansicht einer bevorzugten Ausführungsform eines erfindungsgemäßen Mehrstufengetriebes;
• 2: Ein beispielhaftes Schaltschema für ein Mehrstufengetriebe gemäß 1;
• 3: Ein Diagramm zur Veranschaulichung des der jeweiligen Übersetzung i eines Ganges entsprechenden Stufensprungs phi für das in 1 gezeigte Getriebe;
• 4: Ein Diagramm zur Veranschaulichung des dem jeweiligen Gang entsprechenden Wirkungsgrades für das in 1 gezeigte Getriebe; und
• 5: Eine schematische Ansicht einer weiteren bevorzugten Ausführungsform eines erfindungsgemäßen Mehrstufengetriebes.

The invention will be explained in more detail below by way of example with reference to the attached figures. These are:

• 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 shown, which in a housing G are arranged, the planetary gear sets P1 . P3 and P4 are designed as minus planetary gear sets and the planetary gear set P2 is designed as a plus-planetary gear set.

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

Furthermore, the third planetary gear set P3 and the second planetary gear set P2 combined or reduced to a Ravigneaux - set with common web and common ring gear; alternatively, the second planetary gear 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 multi-speed transmission according to the invention has a total of eight rotatable shafts, namely the waves 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 connected and via a first brake 04 to the housing G of the transmission can be coupled and via a first clutch 48 with the eighth wave 8th is detachably connectable, with the web of the first planetary gear set P1 connected and via a second clutch 68 with the sixth wave 6 is releasably connectable, which is connected to the component, which the ring gear of the fourth planetary gear set P4 and the sun gear of the third planetary gear set P3 connects with each other. 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 with the bridge of the third planetary gear set P3 and the bridge of the second planetary gear set P2 connected is.

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

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

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

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

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 schematics can be the respective translations i the individual gear steps and the gear steps or increments to be determined therefrom phi to the next higher gear, the value of 9.88 represents the spread of the gearbox.

Typical values for the stand 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 the case of sequential switching, double circuits or group circuits are avoided, since two adjacent gear stages share two switching elements. 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 or air-oil mixture contained therein, 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 can Switching elements (designed as Reibschaltelemente or lamellae switching elements) are used as starting elements.

According to the invention, different gear jumps may result even with the same transmission scheme depending on the switching logic, so that an application- or vehicle-specific variation is made 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 1 based 4 illustrated. Out 4 will be apparent 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 viewed axially between the radially superposed planetary gear sets P4 / P3 and the second planetary gear set P2 is arranged, 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 on the side of the second planetary gear set P2 arranged, which the radially superposed planetary gear sets P3 / P4 opposite. The second clutch 17 is considered in the direction of force flow before the second planetary gear set P2 disposed

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

On the drive side or on the output side, an axle differential and / or a distributor differential can be arranged according to the invention.

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 multistage transmission according to the invention also allows the arrangement of a torsional vibration damper between the 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 electric 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 friction shift elements used can be designed as a load-shifting clutches or brakes. In particular, non-positive clutches or brakes, such as e.g. Multi-plate clutches, band brakes and / or cone clutches are used.

Another advantage of the multistage transmission presented here is that an electric machine can be mounted on each shaft as a generator and / or as an additional drive machine.

LIST OF REFERENCE NUMBERS

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 gear set

P2

second planetary set

P3

third planetary set

P4

fourth planetary set

i

translation

phi

increment

G

casing

eta

efficiency

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 eight rotatable shafts ( 1, 2, 3, 4, 5, 6, 7, 8) and six switching elements (03, 04, 05, 48, 17, 18, 68), comprising brakes (03, 04, 05) and couplings (48, 17 , 18, 68) whose selective engagement causes different ratios between the drive shaft (1) and the output shaft (2), so that nine forward gears and one reverse gear can be realized, wherein the sun gear of the first planetary gear set (P1) with the fourth shaft (4 ), which is connected to the sun gear of the fourth planetary gear set (P4) and can be coupled to the housing (G) of the gearbox via a first brake (04), the eighth shaft (8) being connected to the web of the first planetary gear set (P1). connected via a first coupling (68) with the sixth shaft ( 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) connected to the drive shaft (1) is, via a second clutch (17) releasably connectable to the seventh shaft (7), wherein the seventh shaft (7) with the web of the third planetary gear set (P3) and the web of the second planetary gear set (P2) is connected, the web of the fourth planetary gearset (P4) is connected to the third shaft (3) which can be coupled to the housing (G) of the transmission via a second brake (03), wherein the sun gear of the second planetary gearset (P2) is connected to the fifth shaft (5) is connected, which via a third brake (05) to the housing (G) of the transmission is coupled, wherein the output shaft (2) connected to the ring gear of the second planetary gear set (P2) and the ring gear of the third planetary gear set (P3) is and where a third clutch (18, 48) is provided which releasably connects the eighth shaft (8) to the drive shaft (1) or the fourth shaft (4) to the eighth shaft (8). Multi-step transmission after Claim 1 , characterized in that the third and the fourth planetary gear set (P3, P4) are axially arranged in the same Radsatzebene, said third planetary set (P3) viewed radially above the fourth planetary gear set (P4), whereby the total of four planetary gear sets (P1, P2, P3, P4) spatially axially limited to three Radsatzebenen. Multi-step transmission after Claim 1 , or 2, characterized in that the third planetary set (P3) and the second planetary set (P2) form a Ravigneaux - set with common land 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 - sentence. Multi-speed transmission to one of the Claims 1 or 2 characterized in that the radially superposed planetary gear sets (P4 / P3) axially arranged between the second planetary gear set (P2) and the first planetary gear set (P1) are arranged. Multi-step transmission after Claim 4 , characterized in that the second clutch (17) radially disposed above the first planetary gear set (P1) is arranged. Multi-step transmission after Claim 4 or 5 , characterized in that the first clutch (68) axially between the first planetary gear set (P1) and the radially superposed planetary gear sets (P3 / P4) is arranged. Multi-step transmission after Claim 4 . 5 or 6 , characterized in that the third clutch (48) is arranged radially below the first clutch (68). Multi-step transmission after Claim 1 . 2 , or 3, characterized in that the first planetary gear set (P1) axially disposed between the second planetary gear set (P2) and the radially superposed planetary gear sets (P3 / P4) is arranged. Multi-step transmission after Claim 8 , characterized in that the third brake (05) arranged on the side of the second planetary gear set (P2) is, which is opposite to the radially stacked planetary gear sets (P3 / P4). Multi-speed transmission to one of the Claims 1 to 7 , characterized in that the second clutch (17) on the side of the third planetary gear set (P3) is arranged, which is opposite to the second planetary gear set (P2). Multi-step transmission after Claim 8 or 9 , characterized in that the third clutch (18) is arranged radially below the first brake (04). Multi-step transmission after Claim 8 . 9 , or 11, characterized in that the first clutch (68) axially disposed between the first planetary gear set (P1) and the radially superposed planetary gear sets (P3 / P4) is arranged. Multi-step transmission after Claim 8 . 9 . 11 or 12 , characterized in that the first, third and fourth planetary gear set (P1, P3, P4) are formed as minus planetary gear sets, wherein the second planetary gear set (P2) is designed as a plus-planetary gearset. Multi-speed 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-speed 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 brakes (03, 05), the second forward gear by closing the first and third brake ( 04, 05) and the first clutch (68), the third forward gear by closing the third and first clutch (48, 18, 68) and the third brake (05), the fourth forward gear by closing the first and the second clutch (68, 17) and the third brake (05), the fifth forward speed by closing the third, first and second clutches (48, 18, 68, 17), the sixth forward speed 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 or 18, 17) results, and that the reverse by closing the second and third brakes (03, 05) and the third Coupling (48 or 18) results. Multi-step transmission according to one of the preceding claims, characterized in that the starting takes place by means of the second or the third brake (03, 05) of the transmission.

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