DE102012220517A1 - Multi-stage transmission, particular automatic transmission for motor vehicle, has drive shaft, output shaft and two planetary wheel sets arranged coaxial to axis, where drive- and output shafts are arranged parallel to each other - Google Patents

Abstract

The multi-stage transmission has a drive shaft (1), an output shaft (2) and two planetary wheel sets (P1,P2) which are arranged coaxial to an axis defined by the drive shaft. The drive shaft and the output shaft are arranged parallel to each other. The drive shaft is detachably connected with a fourth shaft (4) by a clutch (14). The fourth shaft connects the latter planetary wheel set with a sun wheel and is coupled to the housing of the transmission by a brake (04). The drive shaft is detachably connected with a fifth shaft by another clutch (15). The fifth shaft is connected with a third shaft (3) by a third clutch (13).

Description

The present invention relates to a multistage 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 automatic transmissions are often described in the prior art and are subject to permanent development and improvement. So these transmissions should have a sufficient number of forward gears and at least one reverse gear and a transmission very well suited for motor vehicles with a high overall spread and favorable increments. Furthermore, these should allow a high starting ratio in the forward direction and contain a direct gear. In addition, automatic transmissions require a low construction cost and a small number of switching elements, with sequential switching mode in each case only one switching element is switched on and a switching element to be switched off.

Such an automatic transmission is for example from the DE 10 2008 000 429 A1 the applicant known. It comprises four coaxial with a main axis of rotation arranged planetary gear sets and six switching elements for switching at least nine forward gears and one reverse gear.

In the known transmission eight rotatable shafts are provided, wherein the first and the second planetary gear set form a switchable transfer gear and the third and fourth planetary gear set form the main gear, the webs of the first and second planetary gear sets are coupled together via a fourth shaft, the is connected to an element of the main gear, wherein the ring gear of the first planetary gear set is coupled to the sun gear of the second planetary gear set via an eighth shaft, which is releasably connectable via a first clutch to the drive shaft, wherein the sun gear of the first planetary gear set by means of a third wave a first brake to the housing of the transmission can be coupled and connected via a second clutch to the drive shaft and wherein the ring gear of the second planetary gear set is coupled by means of a fifth shaft via a second brake to the housing. Further, a seventh shaft is connected to at least one element of the main gearset and coupled via a third brake to the housing, wherein a sixth shaft connected to another element of the main gearset and connectable via a third clutch to the drive shaft and wherein the output shaft with at least one another element of the main gear is connected. The transmission according to the DE 10 2008 000 429 A1 however, is disadvantageously not suitable for installation as a front-transverse system.

The present invention has for its object to provide a multi-step transmission, which has a small space requirement seen axially, so that installation of the transmission and optionally a hybridization of the transmission is made possible as a front-transverse system.

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

Accordingly, a multi-stage transmission is proposed, which has a drive shaft and an output shaft, which are arranged in a housing and parallel to each other. Furthermore, the transmission comprises two planetary gear sets, hereinafter referred to as first and second planetary gear set, which are arranged coaxially to a first axis, which is defined by the drive shaft, at least seven rotatable shafts - hereinafter referred to as drive shaft, output shaft, third, fourth, fifth, sixth and seventh shaft -, a first and a second spur gear and five switching elements, comprising two brakes and three clutches, the selective engagement causes different ratios between the drive shaft and the output shaft, so that preferably six 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 ridge 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, all inner planetary gears mesh with the sun gear and all outer planetary gears with the ring gear, each inner planetary gear, each with an outer Planet wheel meshes. As a result, the ring gear has the same direction of rotation when the web is held on as the sun gear and there is a positive stationary gear ratio.

The fact that the transmission has only two planetary gear sets, a very short length is achieved, so that the transmission can be installed in front-transverse construction.

According to the invention, the drive shaft via a first clutch with a fourth shaft is releasably connectable, which is connected to the sun gear of the second planetary gear and coupled via a second brake to the housing of the transmission and via a second clutch with a fifth shaft releasably connectable, which is connected to the sun gear of the first planetary gear set and the ring gear of the second planetary gear set.

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

Here, the first, second and third clutches and the first and second brakes are arranged coaxially with the first axis.

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 significantly reduced with the multistage transmission according to the invention by a small number of switching elements, which has a positive effect on the weight and the cost. 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 very good efficiency in the main gears with respect to the drag and gear losses.

In addition, the transmission according to the invention is designed such that the space requirement is considered axially low, whereby a hybridization of the transmission is made possible as a front-transverse system.

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 further exemplary circuit diagram for a multi-step transmission according to 1 ;

4 FIG. 2 is a schematic view of another preferred embodiment of a multi-speed transmission based on the embodiment of FIG 1 ;

5 FIG. 2 is a schematic view of a hybridized multi-stage transmission based on the embodiment of FIG 1 ; and

6 FIG. 2 is a schematic view of another embodiment of a hybridized multi-speed transmission based on the embodiment of FIG 1 ,

In 1 a multistage transmission according to the invention is shown, with a first planetary gear P1 and a second planetary gear P2, which is coaxial with a first axis, which by the drive shaft 1 is defined, are arranged. The second axis of the transmission is parallel to the drive shaft through the 1 arranged output shaft 2 Are defined.

The planetary gear sets P1, P2 are executed in the example shown as negative planetary gear sets. In this case, at least one planetary gear set of the transmission can be designed as a plus planetary gear set, if at the same time the web and Hohlradanbindung exchanged and the amount of the stationary gear ratio is increased by 1 compared to the design as a minus planetary gear.

How out 1 can be seen, are five switching elements, namely three brakes 03 . 04 and three couplings 13 . 14 and 15 intended. The couplings and the brakes of the transmission are preferably designed as Reibschaltelemente or lamellar switching elements, but can also be designed as a form-locking switching elements.

With these switching elements a selective switching of six forward gears and one reverse gear can be realized. The multistage transmission according to the invention has a total of at least seven rotatable shafts, wherein the drive shaft, the first shaft 1 and the output shaft, the second shaft 2 of the transmission.

According to the invention in the multi-stage transmission according to 1 provided that the drive shaft 1 via a first clutch 14 with a 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 the housing G of the transmission. Furthermore, the drive shaft 1 via a second clutch 15 with a fifth wave 5 releasably connectable, which is connected to the sun gear of the first planetary gear P1 and the ring gear of the second planetary gear set P2, wherein the drive shaft also has a third clutch 13 with a third wave 3 is releasably connectable, which is connected to the ring gear of the first planetary gear P1 and a first brake 03 can be coupled to the housing G.

Referring to 1 is the web of the first planetary gear set P1 with a sixth shaft 6 which is connected to the output shaft via a first spur gear stage S1, whose first spur gear is designated ST1 and whose second spur gear is designated ST2 2 is operatively connected, wherein the web of the second planetary gear set P2 with a seventh shaft 7 is connected via a second spur S2, whose first spur gear with ST3 and whose second spur gear is denoted by ST4, with the output shaft 2 is actively connected.

Here are the first, second and third clutch 14 . 15 . 13 and the first and second brakes 03 . 04 coaxial with the first axis passing through the drive shaft 1 is defined, arranged. In the example shown, the output shaft 2 connected via a further spur gear S3 with a differential D.

The spatial arrangement of the transmission elements can be arbitrary and is limited only by the dimensions and the external shape; Clutches, brakes or planetary gear sets can be reversed, as long as it allows the binding of the transmission elements.

In 2 is an exemplary circuit diagram of a multi-speed transmission according to 1 and 2 shown. For each gear two 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 φ are taken to the next higher gear example, the value of 6.501 represents the spread of the transmission.

The values for the stationary gear ratios of the planetary gear sets P1, P2 designed as minus planetary gear sets are -2.970 and -1.790 in the example shown, the ratios of the first and second spur gears S1, S2 being 1.000 and 1.383. Out 2 It can be seen that with sequential switching mode only one switching element is switched on and one switching element has to be switched off, since two adjacent gear stages share a switching element.

The first forward gear is obtained by closing the first brake 03 and the second clutch 15 , the second forward gear by closing the second brake 04 and the second clutch 15 , the third forward gear by closing the first and second clutches 14 . 15 in the example shown executed as direct gear fourth forward gear by closing the second and third clutch 15 . 13 , the fifth forward gear by closing the first and third clutch 14 . 13 and the sixth forward gear is obtained by closing the second brake 04 and the third clutch 13 , wherein the reverse gear by closing the first brake 03 and the first clutch 14 results. The fact that in the first forward gear and in reverse the first brake 03 is closed, this switching element can be used as a starting element.

The spread of the transmission can be varied by varying the stationary gear ratios of the planetary gear sets and the Stirnradstufenübersetzungen. This is based on the switching matrix according to 3 In this case, the values for the stationary gear ratios of the planetary gear sets P1, P2 are respectively -2.874 and -1.950, with the ratios of the first and second spur gears S1, S2 being 1.000 and 1.513, so that there is a spread of 7.024.

According to the invention, even with the same transmission scheme depending on the switching logic different gear jumps, so that an application or vehicle-specific variation is possible.

This in 4 example shown differs from the exemplary embodiment 1 in that the transmission is mirrored about the vertical axis, the drive shaft 1 passed through the transmission to the drive for To get transmission input side, for which purpose the fourth wave 4 is designed as a hollow shaft through which the drive shaft 1 is guided.

This in 5 embodiment shown corresponds to the embodiment according to 1 with the difference that an electric machine E is provided, which on the drive shaft 1 the transmission is arranged and with the drive shaft 1 directly connected. Here, a further clutch K0 is provided, through which the internal combustion engine, not shown, can be decoupled from the transmission, whereby all gears of the transmission can be driven purely electric.

Alternatively to the direct connection of the electric machine E with the drive shaft 1 can the electric machine E paraxial to the drive shaft 1 be arranged and via a wheel or a chain drive with the drive shaft 1 be connected. This embodiment is the subject of 6 , The gear shown here corresponds to the gearbox 1 with the difference that an electric machine E paraxial to the drive shaft 1 arranged and via a fourth spur gear S4 with the drive shaft 1 connected is. At the in 6 example shown is analogous to the example according to 5 between the internal combustion engine (not shown) and the drive shaft 1 another clutch K0 arranged to allow a purely electric driving.

In principle, an electrical machine or a further drive source can be arranged on each shaft of the transmission according to the invention.

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 advantageous developments, 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 drive motor.

The multistage transmission according to the invention also allows the arrangement of a torsional vibration damper between the drive motor and transmission.

In the context of a further, not shown embodiment of the invention can on each shaft, preferably on the drive shaft 1 or the output shaft 2 , a wear-free brake, such as a hydraulic or electric retarder or the like, be arranged, which is particularly important for use in commercial vehicles of particular importance. Furthermore, 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 power shift clutches or brakes. In particular, non-positive clutches or brakes, such as e.g. Multi-plate clutches, band brakes and / or cone clutches are used. Furthermore, the switching elements used can be designed as a form-locking switching elements.

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

03

first brake

04

second brake

13

third clutch

14

first clutch

15

second clutch

e

electric machine

G

casing

K0

further coupling

P1

first planetary gear set

P2

second planetary gear set

S1

first spur gear

S2

second spur gear

S3

third spur gear

S4

fourth spur gear

ST1

first spur gear of the first spur gear S1

ST2

second spur gear of the first spur gear S1

ST3

first spur gear of the second spur gear S2

ST4

second spur gear of the second spur gear S2

i

translation

φ

increment

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 102008000429 A1 [0004, 0005]

Claims (6)

Multi-speed transmission, in particular automatic transmission for a motor vehicle, comprising a drive shaft ( 1 ), an output shaft ( 2 ), which are arranged parallel to each other, a first planetary gear set (P1) and a second planetary gear set (P2) which are coaxial with a first axis, which by the drive shaft ( 1 ), are arranged, wherein the drive shaft ( 1 ) via a first clutch ( 14 ) with a fourth wave ( 4 ) is releasably connectable connected to the sun gear of the second planetary gear set (P2) and via a second brake ( 04 ) can be coupled to the housing (G) of the transmission, wherein the drive shaft ( 1 ) via a second clutch ( 15 ) with a fifth wave ( 5 ) is releasably connectable, which is connected to the sun gear of the first planetary gear set (P1) and the ring gear of the second planetary gear set (P2) and via a third clutch ( 13 ) with a third wave ( 3 ) is detachably connectable, which with the ring gear of the first planetary gear set (P1) and connected via a first brake ( 03 ) to the housing (G) can be coupled, wherein the web of the first planetary gear set (P1) with a sixth shaft ( 6 ), which via a first spur gear (S1) with the output shaft 2 is operatively connected and wherein the web of the second planetary gear set (P2) with a seventh wave ( 7 ), which via a second spur gear (S2) with the output shaft ( 2 ) is operatively connected. Multi-speed transmission according to claim 2, characterized in that the first, second and third clutches ( 14 . 15 . 13 ) and the first and second brakes ( 03 . 04 ) coaxial with the first axis passing through the drive shaft ( 1 ) are arranged. Multi-step transmission according to one of the preceding claims, characterized in that the planetary gear sets (P1, P2) are designed as negative planetary gear sets. Multi-step transmission according to one of the preceding claims, characterized in that an electric machine (E) is provided, which on the drive shaft ( 1 ) of the transmission is arranged and with the drive shaft ( 1 ) is directly connected or which axis parallel to the drive shaft ( 1 ) is arranged and with the drive shaft ( 1 ) is connected via a wheel step (S4) or a chain drive. Multi-speed transmission according to claim 4, characterized in that the internal combustion engine can be decoupled from the transmission by means of a further clutch (K0), whereby all gears of the transmission can be driven purely electrically. Multi-speed transmission according to one of the preceding claims, characterized in that six forward gears and one reverse gear are realizable, wherein the first forward gear by closing the first brake ( 03 ) and the second clutch ( 15 ), the second forward gear by closing the second brake ( 04 ) and the second clutch ( 15 ), the third forward gear by closing the first and second clutch ( 14 . 15 ), the fourth forward gear by closing the second and third clutch ( 15 . 13 ), the fifth forward gear by closing the first and third clutch ( 14 . 13 ) and wherein the sixth forward gear by closing the second brake ( 04 ) and the third clutch ( 13 ), wherein the reverse gear by closing the first brake ( 03 ) and the first clutch ( 14 ).

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