DE102009054454A1 - Multi-stage planetary gearbox i.e. automatic gearbox, for use in motor vehicle, has drive shaft connected with rod of planetary gear set and ring gear of another planetary gear set, and another shaft connected with sun gear of former set - Google Patents

Abstract

The gearbox has a first planetary gear set (P1) whose ring gear is operatively connected with a first drive shaft (1) that is connected with a rod of a second planetary gear set (P2). A ring gear of the second gear set is connected with a second drive shaft (7) that is connected with a sun gear of a third planetary gear set (P3). The second drive shaft is detachably connected with a third drive shaft (3) by a clutch (37). A fourth drive shaft is connected with a rod of the third planetary gear set and a ring gear of a fourth planetary gear set (P4).

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, in the first power path, two clutches are required for transmitting the torque from the transfer gearset to two elements of the double planetary gearset. 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 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 but 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 optimize the weight 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 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 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 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 arranged axially in the order of the first planetary gear set, second planetary gear set, third planetary gear set, fourth planetary gear set; Furthermore, 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 gearset is operatively connected to a housing of the transmission, wherein the web of the first planetary gear set is connected to the eighth shaft connected to the sun gear of the second planetary gear set, which releasably connectable to the fourth shaft via a first clutch is, which is connected to the sun gear of the fourth planetary gear set and can be coupled via a second brake to a housing of the transmission. Further, the ring gear of the first planetary gear set is operatively connected to the drive shaft connected to the web of the second planetary gear set, wherein the ring gear of the second planetary gear set is connected to the connected to the sun gear of the third planetary gear seventh shaft, which releasably connectable via a second clutch with the third shaft is connected to the web of the fourth planetary gear set, via a first brake to a housing of the transmission is coupled and via a third clutch with the connected to the ring gear of the third planetary gear sixth shaft is releasably connectable, wherein the output shaft with the web of the third planetary gear set and the ring gear of the fourth planetary gear set is connected.

Here, the sun gear of the first planetary gear set may be coupled to a housing of the transmission, in which case the ring gear of the first planetary gear set with the drive shaft via a connected to the ring gear of the first planetary gear fifth shaft and a fifth shaft to the drive shaft releasably connecting the fourth clutch is detachably connectable.

In the context of a further embodiment of the invention, the sun gear of the first planetary gear set can be coupled to the housing via a further shaft connected to the sun gear of the first planetary gear set and a third brake releasably connecting the further shaft to a housing of the transmission, in which case the ring gear of the first planetary gear set is directly connected to the drive 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, with the multistage transmission according to the invention by a small Number of switching elements, the construction cost significantly reduced. 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 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 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 : an exemplary circuit diagram for a multi-step transmission according to 1 ;

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

4 : an exemplary circuit diagram for a multi-step transmission according to 3 ; and

5 - 12 : alternately a schematic view of a preferred embodiment of a multi-speed transmission according to the invention and the corresponding exemplary circuit diagram for four further preferred embodiments.

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 P5 are in the in 1 shown example designed as negative planetary gear sets.

According to the invention, at least one planetary gear set may 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 compared to the execution as a minus planetary gear 1 is increased.

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 15 . 36 . 37 and 48 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 brake 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.

According to a preferred embodiment of the invention, the subject of the 1 is, 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 eighth shaft connected to the sun gear of the second planetary gear set P2 8th Connected via a first clutch 48 with the fourth wave 4 is releasably connectable, which is connected to the sun gear of the fourth planetary gear set P4 and a second brake 04 can be coupled to a housing G of the transmission. Furthermore, the ring gear of the first planetary gear set P1 is connected to the drive shaft connected to the web of the second planetary gear set P2 1 via a fifth shaft connected to the ring gear of the first planetary gear set P1 5 and the fifth wave 5 with the drive shaft 1 releasably connecting fourth clutch 15 detachably connectable, wherein the ring gear of the second planetary gear P2 with the connected to the sun gear of the third planetary gear set P3 seventh wave 7 is connected, which via a second clutch 37 with the third wave 3 is detachably connectable, which is connected to the web of the fourth planetary gear set P4, via a first brake 03 can be coupled to a housing G of the transmission and a third clutch 36 with the sixth shaft connected to the ring gear of the third planetary gear set P3 6 is detachably connectable, wherein the output shaft 2 is connected to the web of the third planetary gear set P3 and the ring gear of the fourth planetary gear set P4.

In the context of another embodiment of the invention, the subject of the 3 is, is the sun gear of the first planetary gear P1 via a connected to the sun gear of the first planetary gear P1 further wave 5 ' and one the further wave 5 ' with a housing G of the transmission releasably connecting third brake 05 can be coupled to the housing G, wherein the ring gear of the first planetary gear P1 with the drive shaft 1 directly connected.

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 8.994 represents the spread of the transmission.

Typical values for the stationary ratios of the planetary gear sets P1, P2, P3 and P4 are -1.6, -2.04, -3.417 and -1.603, respectively. 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.

The first forward speed results from closing the first brake 03 and the third and fourth clutches 36 . 15 , the second forward speed by closing the second brake 04 and the third and fourth clutches 36 . 15 , the third forward by closing the second brake 04 and the first and third clutches 48 . 36 , the fourth forward speed by closing the first, third and fourth clutch 48 . 36 . 15 which preferably performs a forward direct fifth forward gear by closing the first, second and third clutches 48 . 37 . 36 , the sixth forward speed by closing the second, third and fourth clutches 37 . 36 . 15 , the seventh forward speed by closing the first, second and fourth clutches 48 . 37 . 15 , the eighth forward by closing the second brake 04 and the second and fourth clutches 37 . 15 and the ninth forward speed is achieved by closing the second brake 04 and the first and second clutches 48 . 37 , wherein the reverse gear by closing the first brake 03 and the first and fourth clutches 48 . 15 results.

Due to the fact that in first forward gear and in reverse the first brake 03 and the fourth clutch 15 are closed, these switching elements can be used as starting elements.

This according to the embodiment 3 appropriate circuit diagram is the subject of 4 , It corresponds to the circuit diagram according to 2 with the difference that the fourth clutch 15 through the third brake 05 is 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.

In the context of further embodiments of the invention, the releasable coupling of the ring gear of the third planetary gear set P3 with the third shaft 3 by means of the third clutch 36 be replaced by a rigid connection, when the rigid connection of the web of the third planetary gear P3 with the output shaft is replaced by a releasable connection by means of a clutch or if the rigid connection of the sun gear of the third planetary gear P3 with the seventh shaft by a detachable connection by means of a Coupling is replaced.

The embodiments corresponding to these variants and the corresponding circuit diagrams are the subject of 5 to 12 , Here, the couplings are denoted by two-digit reference numerals, wherein the two locations each denote a releasably connectable by the coupling with another shaft shaft.

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 be separated as required by a coupling element of a drive motor, wherein as a coupling element, 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. 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

5 '

another wave

6

sixth wave

7

seventh wave

8th

eighth wave

03

first brake

04

second brake

05

third brake

15

fourth clutch

28

clutch

36

third clutch

37

second clutch

47

clutch

48

first clutch

68

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 (4)

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 . 5 ' . 6 . 7 . 8th ,) and at least six switching elements ( 03 . 04 . 05 . 15 . 36 . 37 . 48 ), comprising brakes ( 03 . 04 . 05 ) and couplings ( 15 . 36 . 37 . 48 ), 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 operatively connected to a housing (G) of the transmission, wherein the web of the first planetary gear set (P1) with that with the sun gear of the second planetary gear set (P2) connected eighth wave ( 8th ) connected via a first clutch ( 48 ) with the fourth wave ( 4 ) is releasably connectable, which is connected to the sun gear of the fourth planetary gear set (P4) 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 drive shaft connected to the web of the second planetary gear set (P2) ( 1 ) is operatively connected, wherein the ring gear of the second planetary gear set (P2) with the connected to the sun gear of the third planetary gear set (P3) seventh wave ( 7 ) which is connected via a second clutch ( 37 ) with the third wave ( 3 ) is releasably connectable, which is connected to the web of the fourth planetary gear set (P4), via a first brake ( 03 ) can be coupled to a housing (G) of the transmission and via a third clutch ( 36 ) with the sixth shaft connected to the ring gear of the third planetary gear set (P3) ( 6 ) is detachably connectable, wherein the output shaft ( 2 ) is connected to the web of the third planetary gear set (P3) and the ring gear of the fourth planetary gear set (P4). Multi-speed transmission according to claim 1, characterized in that the sun gear of the first planetary gear set (P1) is coupled to a housing (G) of the transmission, in which case the ring gear of the first planetary gear set (P1) with the bridge of the second planetary gear set (P2 ) connected drive shaft ( 1 ) via a with the ring gear of the first planetary gear set (P1) connected fifth shaft ( 5 ) and one the fifth wave ( 5 ) with the drive shaft ( 1 ) detachably connecting fourth coupling ( 15 ) is releasably connectable. Multi-speed transmission according to claim 1, characterized in that the sun gear of the first planetary gear set (P1) via a further shaft connected to the sun gear of the first planetary gear set (P1) ( 5 ' ) and one the further wave ( 5 ' ) with a housing (G) of the transmission releasably connecting third brake ( 05 ) to the housing (G) can be coupled, wherein the ring gear of the first planetary gear set (P1) with the drive shaft ( 1 ) is directly connected. Multi-speed transmission according to claim 2 or 3, characterized in that in the event that the sun gear of the first planetary gear set (P1) is coupled to a housing (G) of the transmission, in which case the ring gear of the first planetary gear set (P1) with the the input shaft of the second planetary gear set (P2) ( 1 ) via a with the ring gear of the first planetary gear set (P1) connected fifth shaft ( 5 ) and one the fifth wave ( 5 ) with the drive shaft ( 1 ) detachably connecting fourth coupling ( 15 ) is releasably connectable, the first forward gear by closing the first brake ( 03 ) and the third and fourth clutch ( 36 . 15 ), the second forward gear by closing the second brake ( 04 ) and the third and fourth clutch ( 36 . 15 ), the third forward speed by closing the second brake ( 04 ) and the first and third clutch ( 48 . 36 ), the fourth forward gear by closing the first, third and fourth clutch ( 48 . 36 . 15 ), the fifth forward gear by closing the first, second and third clutch ( 48 . 37 . 36 ), the sixth forward speed by closing the second, third and fourth clutch ( 37 . 36 . 15 ), the seventh forward gear by closing the first, second and fourth clutch ( 48 . 37 . 15 ), the eighth forward by closing the second brake ( 04 ) and the second and fourth clutch ( 37 . 15 ) and that the ninth forward by closing the second brake ( 04 ) and the first and second clutches ( 48 . 37 ), wherein the reverse gear by closing the first brake ( 03 ) and the first and fourth clutch ( 48 . 15 ), wherein, in the event that the sun gear of the first planetary gear set (P1) via a further shaft connected to the sun gear of the first planetary gear set (P1) ( 5 ' ) and one the further wave ( 5 ' ) with a housing (G) of the transmission releasably connecting third brake ( 05 ) can be coupled to a housing (G), the fourth clutch ( 15 ) by the third brake ( 05 ) is replaced.

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