DE102009047268A1 - Multi-stage planetary transmission i.e. automatic transmission, for use in passenger car, has clutch detachably connecting shaft to drive shaft or another shaft to drive shaft or latter shaft to former shaft - Google Patents

Abstract

The transmission has four planetary gear sets (P1-P4) arranged in a housing (G), where one of the planetary gear sets is designed as a plus planetary gear set and the other planetary gear sets are designed as minus-planetary gear sets. A shaft (8) is connected to webs of the second and third gear sets. An output shaft (2) is connected to a web of the fourth gear set. A drive shaft (1) is connected to an internal gear of the third gear set. A clutch (17) detachably connects another shaft (7) to the drive shaft or the former shaft to the drive shaft or the latter shaft to the former shaft.

Description

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

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 generate 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 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.

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 detachably connectable via a first clutch to the drive shaft and that the sun gear of the first planetary gear set by means of the third shaft via a first brake to a housing of the transmission can be coupled and via a second clutch can be detachably connected to the drive shaft, wherein the ring gear of the second planetary gear set is coupled by means of the fifth shaft via a second brake to a housing of the transmission. 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 with at least one further element of the main gearset is constantly connected and releasably connectable 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 a Ravigneaux set with common web and common ring gear.

The present invention has for its object to propose a multi-speed transmission of the type mentioned, which has eight forward gears and at least one reverse gear with sufficient translation, in which the construction cost and size, especially the overall length, or the weight can be 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, at least four planetary gear sets, hereinafter referred to as 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 five switching elements , comprising brakes and clutches, provided whose selective engagement causes different ratios between the drive and the output, so that preferably ten forward gears and two reverse gears can be realized.

The planetary gear sets are axially arranged in the order of the first planetary gearset, second planetary gearset, third planetary gearset, fourth planetary gearset, wherein the first planetary gear set is designed as a plus-planetary gear set and the remaining planetary gear sets are designed as minus planetary gear sets.

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, the web of the first planetary gear set is connected to the third shaft, which is coupled via a first brake to a housing of the transmission, wherein the sun gear of the first planetary gear set is connected to the fourth shaft, which is connected to the sun gear of the second planetary gear set and is connected via a second brake to a housing of the transmission and wherein the ring gear of the first planetary gear set is connected to the sixth shaft, which is connected to the ring gear of the fourth planetary gear set and releasably connectable via a first clutch to the fifth shaft.

According to the fifth shaft is connected to the ring gear of the second planetary gear set and releasably connectable via a second clutch with the seventh while, which is connected to the sun gear of the third planetary gearset and the sun gear of the fourth planetary gear set and via a third clutch with the ring gear of the third planetary gear set connected drive shaft is detachably connectable.

Furthermore, the eighth shaft is connected to the web of the second planetary gearset and the land of the third planetary gearset, wherein the output shaft is connected to the land of the fourth planetary gearset.

As an alternative to the third clutch, which releasably connects the drive shaft to the seventh shaft, a clutch can be provided which removably connects the eighth shaft to the drive shaft or the seventh shaft to the eighth shaft.

The inventive design of the multi-speed transmission results in particular for passenger cars suitable translations and increased total 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 drives 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.

The invention will be explained in more detail below by way of example with reference to the attached figures. In these represent

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

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

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

4 : An exemplary circuit diagram for a multi-step transmission according to 1 . 2 and 3 ,

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

How out 1 can be seen, are five switching elements, namely two brakes 03 . 04 and three couplings 17 . 56 . 57 intended. The spatial arrangement of the switching elements can be arbitrary and is limited only by the dimensions and the external shape. The clutches and the brakes of the transmission are preferably designed as Reibschaltelemente or lamellar switching elements.

With these switching elements a selective switching of eight 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 web of the first planetary gear set P1 with the third wave 3 connected, which has a first brake 03 can be coupled to a housing G of the transmission, wherein the sun gear of the first planetary gear set P1 with the fourth wave 4 connected to the sun gear of the second planetary gear set P2 and via a second brake 04 can be coupled to a housing G of the transmission and wherein the ring gear of the first planetary gear set P1 with the sixth shaft 6 connected to the ring gear of the fourth planetary gear set P4 and via a first clutch 56 with the fifth wave 5 is detachably connectable.

According to the invention, the fifth wave 5 connected to the ring gear of the second planetary gear set P2 and via a second clutch 57 with the seventh wave 7 releasably connectable, which is connected to the sun gear of the third planetary gear set P3 and the sun gear of the fourth planetary gear set P4 and a third clutch 17 with the drive shaft connected to the ring gear of the third planetary gear set 1 is detachably connectable.

Further, the eighth wave 8th connected to the web of the second planetary gear set P2 and the web of the third planetary gear set P3, wherein the output shaft 2 is connected to the web of the fourth planetary gear set P4.

Alternative to the third clutch 17 which releasably connects the drive shaft with the seventh shaft may be a third clutch 18 be provided, which is the eighth wave 8th with the drive shaft 1 releasably connects, as based on 2 illustrated; this in 2 Gearbox shown differs from the gearbox 1 only through the clutch 18 which the clutch 17 replaced.

This in 3 illustrated embodiment differs from the exemplary embodiment 1 in that instead of the third clutch 17 a third clutch 78 is provided by the seventh wave 7 with the eighth wave 8th is detachably connectable.

According to the invention, the couplings 56 and 57 axially considered between the second and the third planetary gear set P2, P3 be arranged, wherein the clutch 56 viewed radially may be arranged substantially above the second planetary gear set P2. The coupling 17 . 18 respectively. 78 is axially disposed between the second and third planetary gear set P2, P3.

In 4 is an exemplary circuit diagram of a multi-speed transmission according to 1 . 2 and 3 shown. For each gear three switching elements are closed. The shift pattern, 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 7.965 represents the spread of the transmission.

Typical values for the stationary ratios of the planetary gear sets P1, P2, P3 and P4 are 2.773, -3.222, -1.6 and -3.9, respectively. Out 4 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.

The first forward gear is obtained by closing the first and second brakes 03 . 04 and the third clutch 17 respectively. 18 respectively. 78 , the second forward gear by closing the first and second brakes 03 . 04 and the second clutch 57 , the third forward gear by closing the first brake 03 and the second and third clutches 57 . 17 respectively. 18 respectively. 78 , the fourth forward gear by closing the first brake 03 and the first and second clutches 56 . 57 , the fifth forward gear by closing the first brake 03 and the first and third clutches 56 . 17 respectively. 18 respectively. 78 , the preferably executed as a direct gear sixth forward gear by closing all couplings 56 . 57 . 17 respectively. 18 respectively. 78 , the seventh forward gear by closing the second brake 04 and the first and third clutches 56 . 17 respectively. 18 respectively. 78 and the eighth forward gear is obtained by closing the second brake 04 and the first and second clutches 56 . 57 , wherein the reverse gear by closing the first and second brake 03 . 04 and the first clutch 56 results.

Due to the fact that in the first forward and in the first reverse the brakes 03 and 04 are closed, these Scheltelemente can be used as a starting element.

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.

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 can turn 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. B. a hydraulic or electric retarder or the like, be arranged, which is particularly important for use in commercial vehicles of particular importance. Furthermore, for driving 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. B. multi-plate clutches, band brakes and / or cone clutches are used.

However, it is also possible in principle to execute the switching elements in a form-fitting manner (as a claw or synchronization element).

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.

Of course, also falls any constructive training, especially any spatial arrangement of the planetary gear sets and the switching elements in itself and to one another and as far as technically feasible, within the scope of the present claims without affecting the function of the transmission, as indicated in the claims, also if these training are not explicitly shown in the figures or in the description.

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

first brake

04

second brake

17

third clutch

18

third clutch

56

first clutch

57

second clutch

78

third clutch

P1

first planetary gear set

P2

second planetary set

P3

third planetary set

P4

fourth planetary set

i

translation

phi

increment

G

casing

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19949507 A1 [0003]
• DE 10213820 A1 [0005]
• DE 2936969 A1 [0006]
• DE 102005010210 A1 [0007]
• DE 102006006637 A1 [0007]
• DE 102008000428 [0009]

Claims (3)

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 ) and at least five switching elements ( 03 . 04 . 17 respectively. 18 respectively. 78 . 56 . 57 ), comprising brakes ( 03 . 04 ) and couplings ( 17 respectively. 18 respectively. 78 . 56 . 57 ), whose selective engagement different transmission ratios between the drive shaft ( 1 ) and the output shaft ( 2 ), so that eight forward gears and one reverse gear can be realized, wherein the web of the first planetary gear set (P1) with the third shaft ( 3 ) connected via a first brake ( 03 ) is coupled to a housing (G) of the transmission, wherein the sun gear of the first planetary gear set (P1) with the fourth wave ( 4 ) connected to the sun gear of the second planetary gear set (P2) and via a second brake ( 04 ) is connectable to a housing (G) of the transmission, wherein the ring gear of the first planetary gear set (P1) with the sixth shaft ( 6 ) connected to the ring gear of the fourth planetary gear set (P4) and via a first clutch ( 56 ) with the fifth wave ( 5 ) is releasably connectable, the fifth wave ( 5 ) connected to the ring gear of the second planetary gear set (P2) and via a second clutch ( 57 ) with the seventh wave ( 7 ) is releasably connectable, which is connected to the sun gear of the third planetary gear set (P3) and the sun gear of the fourth planetary gear set (P4), wherein the eighth wave ( 8th ) is connected to the web of the second planetary gear set (P2) and the web of the third planetary gear set (P3) and the output shaft ( 2 ) is connected to the web of the fourth planetary gear set (P4), wherein the drive shaft ( 1 ) is connected to the ring gear of the third planetary gear set (P3) and wherein a third clutch ( 17 respectively. 18 respectively. 78 ), which is the seventh wave ( 7 ) with the drive shaft ( 1 ) or the eighth wave ( 8th ) with the drive shaft ( 1 ) or the seventh wave ( 7 ) with the eighth wave ( 8th ) releasably connects. Multi-speed transmission according to claim 1, characterized in that the planetary gear sets (P2, P3, P4) are formed as minus planetary gear sets, wherein the planetary gear set (P1) is designed as a plus-planetary gearset. Multi-speed transmission according to claim 1 or 2, characterized in that the first forward gear is obtained by closing the first and second brake ( 03 . 04 ) and the third clutch ( 17 ) respectively. ( 18 ) respectively. ( 78 ), the second forward gear by closing the first and second brake ( 03 . 04 ) and the second clutch ( 57 ), the third forward gear by closing the first brake ( 03 ) and the second and third clutches ( 57 ) 17 ) respectively. ( 18 ) respectively. ( 78 ), the fourth forward gear by closing the first brake ( 03 ) and the first and second clutches ( 56 . 57 ), the fifth forward gear by closing the first brake ( 03 ) and the first and third clutch ( 56 ) 17 ) respectively. ( 18 ) respectively. ( 78 ), the sixth forward gear by closing all clutches ( 56 ) 57 ) 17 ) respectively. ( 18 ) respectively. ( 78 ), the seventh forward gear by closing the second brake ( 04 ) and the first and third clutch ( 56 ) 17 ) respectively. ( 18 ) respectively. ( 78 ) and that the eighth forward gear by closing the second brake ( 04 ) and the first and second clutches ( 56 . 57 ), wherein the reverse gear by closing the first and second brake ( 03 . 04 ) and the first clutch ( 56 ).

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