DE102009047279A1 - Multi-speed transmission in planetary design, particularly automatic transmission for motor vehicle, has drive shaft, output shaft, four planetary gear sets arranged in housing, eight rotatable shafts and six switching elements - Google Patents

Abstract

The multi-speed transmission has a drive shaft (1), an output shaft (2), four planetary gear sets (P1,P2,P3,P4) arranged in a housing (G), eight rotatable shafts (3-8) and six switching elements. A sun wheel of the former planetary gear set is coupled to the housing of the transmission. The bar of the former planetary gear set is connected with the sixth 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, particularly for motor vehicles, include, in the prior art, planetary gear sets that are switched by means of friction elements, such as clutches and brakes, and usually with a slip element and optionally a lockup clutch, such as a hydrodynamic torque converter or a fluid coupling connected.

Such a transmission goes out of the EP 0 434 525 A1 out. It essentially comprises a drive shaft and an output shaft, which are arranged parallel to one another, a double planetary gearset arranged concentrically with the output shaft and five shifting elements in the form of three clutches and two brakes, whose optional blocking determines in pairs the different gear ratios between the drive shaft and the output shaft , Here, the transmission has a Vorschaltradsatz and two power paths, so that six forward gears are achieved by the selective pairwise intervention of the five shift elements.

In this case, two clutches are required for transmitting the torque from the transfer gearset to two elements of the double planetary gearset in the first power path. These are arranged in the direction of power flow essentially behind the transfer gearset in the direction of the double planetary gear set. In the second power path, a further clutch is provided which removably connects this with another element of the double planetary gear set. Here, the clutches are arranged such that the inner disc carrier forms the output.

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 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.

In this case, the first and the second planetary gear set, which are preferably designed as minus planetary gear sets, form a switchable transfer gearset, the third and the fourth planetary gear set forming 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 via the eighth shaft is, which is detachably 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 can be coupled and releasably connected 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 of 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 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 continuously connected to the ring gear of the fourth planetary gear set and the web of the third planetary gear and releasably connectable via the third clutch to the drive shaft. Furthermore, 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 gear set. Furthermore, the third and the fourth planetary gear set to a Ravigneaux set with a common bridge and a common ring gear composed or reduced.

The present invention has for its object to propose a multi-speed transmission of the type mentioned, which has nine forward gears and at least one reverse gear with sufficient translation, in which the construction cost and size, in particular the length or the weight are optimized and also the efficiency in terms the drag and gearing losses is improved. 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 motor vehicle drive in standard longitudinal design.

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 the first, second, third and fourth planetary gear set, 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 two brakes and clutches, provided whose selective engagement causes different ratios between the drive and the output, so that preferably nine forward gears and one reverse gear can be realized.

The planetary gear sets are preferably designed as negative planetary gear sets.

A simple minus planetary gear known to include a sun gear, a ring gear and a web 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 gear includes 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 a preferred embodiment of the invention, the sun gear of the first planetary gear set is coupled to a housing of the transmission, wherein the web of the first planetary gear set is connected to the connected to the ring gear of the third planetary gear sixth shaft, which releasably connectable via a first clutch with the fourth shaft is, which is connected to the sun gear of the second planetary gear set and can be coupled via a second brake to a housing of the transmission. Furthermore, the ring gear of the first planetary gear set is connected to the drive shaft, which is releasably connectable via a second clutch to the eighth shaft connected to the web of the third planetary gear set, wherein the eighth shaft connected via a third clutch to the ring gear of the fourth planetary gear set seventh shaft is detachably connectable.

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

In this case, a fourth clutch, a fifth clutch or a sixth clutch is provided by the closing of the fourth planetary gear set is blockable. Preferably, the fourth clutch is designed as a clutch which releasably connects the fifth shaft to the seventh shaft, wherein the fifth clutch is designed as a clutch which releasably connects the output shaft to the fifth shaft and wherein it is designed as a sixth clutch coupling, which Output shaft with the seventh shaft releasably connects.

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 enable a starting operation with a start-up element integrated in the transmission. Preferably, a suitable Switching element, which is operated in the first forward gear and in reverse gear.

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 is reduced in the multi-step transmission in an advantageous manner. 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 at the shafts, 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. These are:

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

4 : an exemplary circuit diagram for a multi-step transmission according to 1 ,

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. The planetary gear sets P1, P2, P3 and P4 are in the in 1 shown example designed as negative planetary gear sets. According to the invention, at least one planetary gear set can be designed as a positive planetary gear set, if at the same time the web and Hohlradanbindung exchanged and the amount of stationary translation of the planetary gear is increased by 1 compared to the design as a minus planetary gear.

In the embodiment shown, the planetary gear sets are arranged axially in the order P1, P2, P3, P4.

How out 1 can be seen, six switching elements, namely two brakes 03 . 04 and four clutches 18 . 46 . 57 and 78 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 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 is the first shaft 1 and the output shaft 2 forms the second shaft of the transmission.

How out 1 can be seen, the sun gear of the first planetary gear P1 is coupled to a housing G of the transmission (shaft 0 ), wherein the web of the first planetary gear P1 with the connected to the ring gear of the third planetary gear P3 sixth shaft 6 Connected via a first clutch 46 with the fourth wave 4 is releasably connectable, which is connected to the sun gear of the second planetary gear P2 and a second brake 04 can be coupled to a housing G of the transmission. Further, the ring gear of the first planetary gear set P1 is connected to the drive shaft 1 connected via a second clutch 18 with the eighth shaft connected to the bridge of the third planetary gear set P3 8th releasably connectable, the eighth wave 8th via a third clutch 78 with the seventh shaft connected to the ring gear of the fourth planetary gear set P4 7 is detachably connectable.

According to the invention, the web of the second planetary gear set P2 is connected to the third shaft 3 connected to the sun gear of the third planetary gear set P3 and via a first brake 03 can be coupled to a housing G of the transmission, wherein the fifth shaft 5 is connected to the ring gear of the second planetary gear set P2 and the sun gear of the fourth planetary gear set P4 and the output shaft 2 is connected to the web of the fourth planetary gear set P4.

At the in 1 shown example, it is provided that the fourth planetary gear P4 by closing a fourth clutch 57 is blockable, with the fourth clutch 57 is designed as a coupling, which is the fifth wave 5 with the seventh wave 7 releasably connects, so by closing the fourth clutch 57 the fourth planetary gear set P4 can be blocked by coupling the ring gear with the sun gear.

This in 2 The embodiment shown differs from the exemplary embodiment 1 in that for blocking the fourth planetary gear set P4, a fifth clutch 25 is provided, via which the output shaft 2 with the fifth wave 5 is detachably connectable, so that the blocking can be done by coupling the web of the fourth planetary gear set P4 with the sun gear of the fourth planetary gear set P4. In contrast to the embodiment according to 1 the planetary gear sets are axially arranged in the order P1, P3, P3, P4.

According to the invention, instead of the fourth clutch 57 or the fifth clutch 25 a sixth clutch 27 be provided, via which the output shaft 2 with the seventh wave 7 is detachably connectable, so that the blocking of the fourth planetary gear set P4 can be done by coupling the web of the fourth planetary gear set P4 with the ring gear of the fourth planetary gear set P4. This embodiment is the subject of 3 , Also in this case, the planetary gear sets are axially arranged in the order P1, P3, P3, P4.

In 4 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 i of the individual gear ratios and the resulting jumps to be determined or increments phi are taken to the next higher gear example, the value of 8.985 represents the spread of the transmission.

Typical values for the stationary ratios of the planetary gear sets P1, P2, P3 and P4, which are designed as minus planetary gear sets, are -3.659, -2.535, -1.6 and -1.886, 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 speed results from closing the first brake 03 and the first and third clutches 46 . 78 , the second forward speed by closing the first and second brakes 03 . 04 and the third clutch 78 , the third forward by closing the first brake 03 and the third and fourth clutches 78 . 57 , the fourth forward by closing the second brake 04 and the third and fourth clutches 78 . 57 , the fifth forward speed by closing the first, third and fourth clutch 46 . 78 . 57 , which preferably performs a direct forward sixth forward gear by closing the second, third and fourth clutch 18 . 78 . 57 , the seventh forward speed by closing the first, second and third clutches 46 . 18 . 78 , the eighth forward speed by closing the first, second and fourth clutches 46 . 18 . 57 and the ninth forward speed is achieved by closing the second brake 04 and the second and fourth clutches 18 . 57 , wherein the reverse gear by closing the first brake 03 and the first and fourth clutches 46 . 57 results.

Due to the fact that in first forward gear and in reverse the first brake 03 and the first clutch 46 are closed, these switching elements can be used as starting elements.

In the event that according to the embodiment of 2 the fourth clutch 57 through the fifth clutch 25 is replaced, which the output shaft 2 with the fifth wave 5 releasably connects, is preferably in the circuit diagram according to 4 the fourth clutch 57 through the fifth clutch 25 replaced. Further, in the case that according to the embodiment according to 3 the fourth clutch 57 through the sixth clutch 27 is replaced, which is the output shaft 2 with the seventh wave 7 releasably connects, preferably in the circuit diagram according to 4 the fourth clutch 57 through the sixth clutch 27 replaced.

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 point of the multi-speed transmission, for example between a while and the housing or to connect two shafts optionally.

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 by a coupling element of a drive motor turn as needed separately, 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 electrical 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.

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

LIST OF REFERENCE NUMBERS

0

wave

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

18

second clutch

25

fifth clutch

27

sixth clutch

46

first clutch

57

fourth clutch

78

third clutch

P1

first planetary gear set

P2

second planetary gear set

P3

third planetary gear set

P4

fourth planetary gear 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

• EP 0434525 A1 [0003]
• DE 102008000428 A1 [0006]

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 eight rotatable shafts ( 1 . 2 . 3 . 4 . 5 . 6 . 7 . 8th ,) and at least six switching elements ( 03 . 04 . 18 . 25 . 27 . 46 . 57 . 78 ), comprising brakes ( 03 . 04 ) and couplings ( 18 . 25 . 27 . 46 . 57 . 78 ), 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 can be realized, wherein the sun gear of the first planetary gear set (P1) is coupled to a housing (G) of the transmission, wherein the web of the first planetary gear set (P1) with the ring gear of the third planetary gear set (P3) associated sixth wave ( 6 ) connected via a first clutch ( 46 ) with the fourth wave ( 4 ) is detachably connectable, which connected to the sun gear of the second planetary gear set (P2) and via a second brake ( 04 ) to a housing (G) of the transmission can be coupled, wherein the ring gear of the first planetary gear set (P1) with the drive shaft ( 1 ) connected via a second clutch ( 18 ) with the 8th shaft connected to the bridge of the third planetary gear set (P3) ( 8th ) is detachably connectable, wherein the eighth wave ( 8th ) via a third clutch ( 78 ) connected to the ring gear of the fourth planetary gear set (P4) seventh wave ( 7 ) is releasably connectable, wherein the web of the second planetary gear set (P2) with the third wave ( 3 ) connected to the sun gear of the third planetary gear set (P3) and via a first brake ( 03 ) can be coupled to a housing (G) of the transmission, wherein the fifth shaft ( 5 ) is connected to the ring gear of the second planetary gear set (P2) and the sun gear of the fourth planetary gear set (P4) and the output shaft ( 2 ) is connected to the web of the fourth planetary gear set (P4) and wherein a fourth clutch ( 57 ), a fifth clutch ( 25 ) or a sixth clutch ( 27 ) is provided by the closing of the fourth planetary gear set (P4) is blockable. Multi-step transmission according to Claim 1, characterized in that the fourth clutch ( 57 ) is designed as a coupling which the fifth wave ( 5 ) with the seventh wave ( 7 ) releasably connects, wherein the fifth clutch ( 25 ) is designed as a coupling which the output shaft ( 2 ) with the fifth wave ( 5 ) releasably connects and being the sixth clutch ( 27 ) is designed as a coupling which the output shaft ( 2 ) with the seventh wave ( 7 ) releasably connects. Multi-speed transmission according to claim 1 or 2, characterized in that the first forward gear by closing the first brake ( 03 ) and the first and third clutch ( 46 . 78 ), the second forward speed by closing the first and second brakes ( 03 . 04 ) and the third clutch ( 78 ), the third forward speed by closing the first brake ( 03 ) and the third and fourth or fifth and sixth clutch ( 78 . 57 respectively. 25 respectively. 27 ), the fourth forward gear by closing the second brake ( 04 ) and the third and fourth or fifth and sixth clutch ( 78 . 57 respectively. 25 respectively. 27 ), the fifth forward speed by closing the first, third and fourth or fifth and sixth clutch ( 46 . 78 . 57 respectively. 25 respectively. 27 ), the sixth forward speed by closing the second, third and fourth or fifth and sixth clutch ( 18 . 78 . 57 respectively. 25 respectively. 27 ), the seventh forward gear by closing the first, second and third clutch ( 46 . 18 . 78 ), the eighth forward speed by closing the first, second and fourth or fifth and sixth clutch ( 46 . 18 . 57 respectively. 25 respectively. 27 ) and that the ninth forward by closing the second brake ( 04 ) and the second and fourth or fifth and sixth clutch ( 18 . 57 respectively. 25 respectively. 27 ), wherein the reverse gear by closing the first brake ( 03 ) and the first and fourth or fifth and sixth clutch ( 46 . 57 respectively. 25 respectively. 27 ).

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