DE102008041197B4 - 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, 15, 17, 18, 58, 68), comprising brakes (03, 04, 05) and couplings (15 , 17, 18, 58, 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, the sun gear of the fourth planetary gear set (P4) via a first brake (03) with a housing (G) rotatably connected to the component (0) is releasably connectable and the web of the second planetary gear set (P2) via the seventh shaft (7) to the web of the fourth planetary gear set (P4) is connected, wherein the seventh shaft (7) via a first coupling (17) with the An Drive shaft (1) is releasably connectable, which is connected to the ring gear of the first planetary gear set (P1), wherein the component which connects the ring gear of the third planetary gear set (P3) with the sun gear of the second planetary gear set (P2), via the sixth shaft (6) is connected to the ring gear of the fourth planetary gear set (P4) and the sixth shaft (6) via a third clutch (68) with the eighth shaft (8) is detachably connected, which connected to the web of the first planetary gear set (P1) is, wherein the web of the third planetary gear set (P3) via a fourth shaft (4) and a third brake (04) to the housing (G) of the transmission is coupled and the sun gears of the first and third planetary gear set (P1, P3) the fifth shaft (5) are connected, which via a second brake (05) to the housing (G) of the transmission is coupled, wherein the output shaft (2) is connected to the ring gear of the second planetary gear set (P2) and wherein a second clutch (18 or 58 b 15) is provided which releasably connects the eighth shaft (8) with the drive shaft (1) or the eighth shaft (8) with the fifth shaft (5) or the fifth shaft (5) with the drive shaft (1).

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 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 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 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, preferably designed as minus planetary gear sets, hereinafter referred to as first, second, third and fourth planetary gearsets, eight rotatable shafts - hereinafter referred to as drive shaft, output shaft, third, fourth, fifth, sixth, seventh and eighth shaft - and six shifting 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 one embodiment of the invention it is provided that the sun gear of the fourth planetary gear set is connected to the third shaft, which is releasably connectable via a first brake with a rotatably connected to a housing member. The web of the fourth planetary gearset is in this case connected to the seventh shaft, which is connected to the web of the second planetary gear set and releasably connectable via a first clutch to the drive shaft, which is connected to the ring gear of the first planetary gear set and a second clutch to the fifth shaft is releasably connectable, which is connected to the sun gears of the first planetary gear set and the third planetary gear set and can be coupled via a second brake to the housing of the transmission.

In addition, the web of the third planetary gear set is connected to the fourth shaft, which can be coupled via a third brake to the housing of the transmission, wherein the ring gear of the fourth planetary gear set is connected to the sixth shaft, which is connected to a component which the ring gear of third planetary gear set connects to the sun gear of the second planetary gear set; the sixth shaft is releasably connectable via a third clutch with the eighth wave, which is connected to the web of the first planetary gearset.

According to the invention, the output shaft is connected to the ring gear of the second planetary gearset.

The inventive design of the multi-speed transmission resulting in particular for passenger cars suitable translations and a significant increase in the overall spread of the multi-speed transmission, creating a Improvement of driving comfort and a significant reduction in consumption 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.

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; and

4 : A diagram to illustrate the corresponding gear for each degree of efficiency for the in 1 shown gearbox.

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

In the embodiment shown, which is particularly suitable for a front-transverse construction, the second and the third planetary gear set P2, P3 axially arranged in the same Radsatzebene arranged, the second planetary gear set P2 is radially disposed over the third planetary gear set P3, whereby the total four planetary gear sets are advantageously limited spatially axially limited to three Radsatzebenen. Here, the ring gear of the third planetary gear set P3 is connected to the sun gear of the second planetary gear set P2. In the power flow direction considered in the train operation, the planetary gear sets are arranged in the order P1, P2 / P3, P4 in this case.

How out 1 can be seen, six switching elements, namely three brakes 03 . 04 . 05 and three couplings 15 . 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 fourth planetary gear set P4 with the third wave 3 connected, which has a first brake 03 with a non-rotatably connected to the housing G device 0 is detachably connectable. The bridge of the fourth planetary set P4 is the seventh wave 7 connected, which connected to the web of the second planetary gear set P2 and via a first clutch 17 with the drive shaft 1 is detachably connectable, wherein the drive shaft 1 connected to the ring gear of the first planetary gear set P1 and the clutch 15 with the fifth wave 5 is detachably connectable, which is connected to the sun gears of the first planetary gear set P1 and the third planetary gear set P3 and a second brake 05 can be coupled to the housing G of the transmission.

Furthermore, the land of the third planetary gear set P3 is the fourth shaft 4 connected via a third brake 04 can be coupled to the housing G of the transmission, wherein the ring gear of the fourth planetary gear set P4 with the sixth shaft 6 is connected, which is connected to the component which connects the ring gear of the third planetary gear set P3 with the sun gear of the second planetary gear set P2 and via a third clutch 68 with the eighth wave 8th is releasably connectable, which is connected to the web of the first planetary gear P1.

How out 1 can be seen, the output shaft 2 connected to the ring gear of the second planetary gear set.

Preferably, the first brake 03 viewed radially below the fourth planetary gear set P4 arranged; the third clutch 68 is axially arranged preferably between the third planetary gear set P3 and the first planetary gear set P1, wherein the second clutch 15 considered in the direction of power flow in train operation before the first planetary gear set P1 is arranged; Further, the first clutch 17 viewed radially above the first planetary gear set P1. Furthermore, the second and the third brake 05 . 04 axially considered preferably arranged side by side.

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, wherein the value 8, 124 represents the spread of the transmission.

Typical values for the stationary ratios of the planetary gear sets P1, P2, P3 and P4 are -2.50, -1.60, -2.20 and -2.50, 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. Furthermore, with the in 1 a total of nine forward gears and a reverse gear can be realized.

The first brake 03 and / or the third 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 then contained, reduced. The other couplings 15 . 17 and the rest of the brakes 03 . 05 are preferably designed as Reibschaltelemente or lamellar switching elements.

The first forward gear is obtained by closing the third clutch 68 and the first and third brakes 03 . 04 , the second forward gear by closing the first and second brakes 03 . 05 and the third clutch 68 , the third forward gear by closing the first brake 03 and the second and third clutches 15 . 68 , the fourth forward gear by closing the first brake 03 and the first and third clutches 17 . 68 , the fifth forward gear by closing the first, second and third clutches 17 . 15 . 68 the sixth forward gear by closing the second brake 05 and the first and third clutches 17 . 68 , the seventh forward gear by closing the third brake 04 and the first and third clutches 17 . 68 , the eighth forward gear by closing the second and third brakes 05 . 04 and the first clutch 17 and the ninth forward gear by closing the third brake 04 and the first and second clutches 17 . 15 , Reverse is achieved by closing the first and third brakes 03 . 04 and the second clutch 15 ,

Due to the fact that in first forward gear and in reverse the first brake 03 and the third brake 04 are closed, these switching elements (designed as Reibschaltelemente or lamellae switching elements) can be 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 according to 1 based 4 illustrated.

According to a further, not shown embodiment of a transmission according to the invention, instead of the second clutch 15 a clutch 18 be provided, which the drive shaft 1 with the eighth wave 8th releasably connects.

Altarnativ to the second couplings 18 respectively. 15 can a clutch 58 be provided, which is the fifth wave 5 with the eighth wave 8th releasably connects. The second couplings 58 and 18 are preferably arranged in the power flow direction in train operation before the first planetary gear set P1.

The circuit diagram corresponding to these embodiments corresponds to that in FIG 2 shown scheme with the difference that the third clutch 15 through the clutch 18 respectively. 15 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 electrical retarder or the like, be arranged, which is particularly important for use in commercial vehicles of particular importance. Furthermore, to drive additional units on each shaft, preferably on the drive shaft 1 or the output shaft 2 be provided a power take-off.

The 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 mounted on each shaft as a generator and / or as an additional drive machine.

LIST OF REFERENCE NUMBERS

0

module

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

third brake

05

second brake

15

second clutch

17

first clutch

18

second clutch

58

second clutch

68

third clutch

P1

first planetary gear set

P2

second planetary set

P3

third planetary set

P4

Fourth planetary gear translation

phi

increment

G

casing

eta

efficiency

Claims (11)

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 ) as well as six switching elements ( 03 . 04 . 05 . 15 . 17 . 18 . 58 . 68 ), comprising brakes ( 03 . 04 . 05 ) and couplings ( 15 . 17 . 18 . 58 . 68 ), whose selective engagement different transmission ratios between the drive shaft ( 1 ) and the output shaft ( 2 ), so that nine forward gears and one reverse gear can be realized, wherein the sun gear of the fourth planetary gear set (P4) via a first brake ( 03 ) with a rotatably connected to the housing (G) component ( 0 ) is releasably connectable and the web of the second planetary set (P2) on the seventh wave ( 7 ) is connected to the bridge of the fourth planetary set (P4), wherein the seventh wave ( 7 ) via a first clutch ( 17 ) with the drive shaft ( 1 ) is detachably connectable, which is connected to the ring gear of the first planetary gear set (P1), wherein the component which connects the ring gear of the third planetary gear set (P3) with the sun gear of the second planetary gear set (P2), via the sixth shaft ( 6 ) is connected to the ring gear of the fourth planetary gear set (P4) and the sixth shaft ( 6 ) via a third clutch ( 68 ) with the eighth wave ( 8th ) is detachably connectable, which is connected to the web of the first planetary gear set (P1), wherein the web of the third planetary gear set (P3) via a fourth wave ( 4 ) and a third brake ( 04 ) is connectable to the housing (G) of the transmission and the sun gears of the first and the third planetary gear set (P1, P3) with the fifth shaft ( 5 ) connected via a second brake ( 05 ) is connectable to the housing (G) of the transmission, wherein the output shaft ( 2 ) is connected to the ring gear of the second planetary gear set (P2) and wherein a second clutch ( 18 respectively. 58 respectively. 15 ), which the eighth wave ( 8th ) with the drive shaft ( 1 ) or the eighth wave ( 8th ) with the fifth wave ( 5 ) or the fifth wave ( 5 ) with the drive shaft ( 1 ) releasably connects. Multi-speed transmission according to claim 1, characterized in that the planetary gear sets (P1, P2, P3, P4) are designed as minus planetary gear sets Multi-speed transmission according to claim 1 or 2, characterized in that the second and third planetary gear sets (P2, P3) are arranged axially in the same Radsatzebene, wherein the second planetary gear set (P2) viewed radially over the third planetary gear set (P3) is arranged, whereby the total of four planetary gear sets (P1, P2, P3, P4) are spatially axially limited to three Radsatzebenen. Multi-step transmission according to one of the preceding claims, characterized in that the first brake ( 03 ) Viewed radially below the fourth planetary gear set (P4) is arranged. Multi-step transmission according to one of the preceding claims, characterized in that the third clutch ( 68 ) axially disposed between the third planetary gear set (P3) and the first planetary gear set (P1) is arranged. Multi-step transmission according to one of the preceding claims, characterized in that the second clutch ( 15 respectively. 18 respectively. 58 ) is arranged in the power flow direction in the train operation before the first planetary gear set (P1). Multi-step transmission according to one of the preceding claims, characterized in that the first clutch ( 17 ) viewed radially above the first planetary gear set (P1) is arranged. Multi-step transmission according to one of the preceding claims, characterized in that the third and second brake ( 04 . 05 ) are arranged side by side viewed axially. Multi-step transmission according to one of the preceding claims, characterized in that the first brake ( 03 ) and / or the third clutch ( 68 ) are designed as claw switching elements, wherein the remaining clutches ( 17 . 15 respectively. 18 respectively. 58 ) and the other brakes ( 04 . 05 ) are designed as Reibschaltelemente. Multi-step transmission according to one of the preceding claims, characterized in that the first forward gear by closing the third clutch ( 68 ) and the first and third brakes ( 03 . 04 ), the second forward gear by closing the first and second brake ( 03 . 05 ) and the third clutch ( 68 ), the third forward gear by closing the first brake ( 03 ) and the second and third clutches ( 15 respectively. 18 respectively. 58 . 68 ), the fourth forward gear by closing the first brake ( 03 ) and the first and third clutch ( 17 . 68 ), the fifth forward gear by closing the first, second and third clutch ( 17 . 18 respectively. 15 respectively. 58 . 68 ) the sixth forward gear by closing the second brake ( 05 ) and the first and third clutch ( 17 . 68 ), the seventh forward gear by closing the third brake ( 04 ) and the first and third clutch ( 17 . 68 ), the eighth forward gear by closing the second and third brakes ( 05 . 04 ) and the first clutch ( 17 ) and the ninth forward gear by closing the third brake ( 04 ) and the first and second clutches ( 17 . 18 respectively. 15 respectively. 58 ) and that the reverse gear by closing the first and third brake ( 03 . 04 ) and the second clutch ( 18 respectively. 15 respectively. 58 ). Multi-step transmission according to one of the preceding claims, characterized in that the starting by means of the first or the third brake ( 03 . 04 ) of the transmission takes place.

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