EP2864669A1

EP2864669A1 - Multi-speed gearbox

Info

Publication number: EP2864669A1
Application number: EP13723466.2A
Authority: EP
Inventors: Stefan Beck; Christian Sibla; Wolfgang Rieger
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2012-06-26
Filing date: 2013-05-14
Publication date: 2015-04-29
Also published as: DE102012210860A1; WO2014000944A1; US20150300460A1; CN104364556A; US9618095B2; CN104364556B

Abstract

The invention relates to a multi-speed gearbox having four planetary gear sets (P1, P2, P3, P4), eight rotatable shafts (1, 2, 3, 4, 5, 6, 7, 8) and six shift elements (03, 04, 13, 14, 26, 7), wherein the sun gear of the first planetary gear set (P1) is connected to the third shaft (3), which is detachably connected to the drive shaft (1) by means of a first clutch (13) and can be coupled to the housing (G) by means of a first brake (03). The drive shaft (1) can be detachably connected to the fourth shaft (4) which is connected to the planet carrier of the third planetary gear set (P3) by means of a second clutch (14), which can be coupled to the planet carrier of the first planetary gear set (P1) by means of a second brake (04) and is coupled to the housing (G). The drive shaft (1) is connected to the sun gear of the fourth planetary gear set (P4). The eighth shaft (8) is connected to the ring gear of the first planetary gear set (P1), to the sun gear of the second planetary gear set (P2) and to the sun gear of the third planetary gear set (P3). The fifth shaft (5) is connected to the planet carrier of the second planetary gear set (P2) and to the ring gear of the third planetary gear set (P3) and can be detachably connected to the seventh shaft (7) which is connected to the ring gear of the fourth planetary gear set (P4) by means of a third clutch (57). The sixth shaft (6) connects to the ring gear of the second planetary gear set (P2) and can be detachably connected to the output shaft (2) of the gearbox by means of a fourth clutch (26), which is connected to the planet carrier of the fourth planetary gear set (P4).

Description

Mehrstufenqetriebe

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.

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. Thus, these transmissions are to require a low construction cost, in particular a small number of switching elements and in sequential switching manner double circuits, i. avoid switching on or off of two switching elements, so that in circuits in defined gear groups only one switching element is changed.

From DE 10 2008 000 428 A1 of the applicant, a multi-speed planetary gear transmission is 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 negative planetary gear sets, that is to say with a negative stationary gear ratio, form a shiftable transfer gearset, the third and the fourth planetary gear set forming a main gearset.

According to the prior art, the switching elements of such executed multi-speed transmission, which are usually designed as multi-plate clutches or brakes, actuated hydraulically, which leads disadvantageously to high hydraulic losses. In order to circumvent these actuation losses, the use of alternatively operable switching elements, for example of electromechanically actuatable switching elements, would be particularly advantageous.

To enable the use of demand-actuated switching elements, the switching elements, in particular the couplings from the outside must be easily accessible.

The present invention has for its object to propose a multi-speed transmission of the type mentioned, which has nine forward gears and one reverse gear with sufficient translation, in which the construction cost, the component load and the size are optimized and also improves the efficiency in terms of drag and gearing losses becomes. Furthermore, the switching elements of the transmission should be easily accessible from the outside, whereby the installation of demand-actuated switching elements is facilitated. In addition, the transmission should be suitable for both a standard and a front-transverse construction.

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

Accordingly, a multi-speed transmission according to the invention is proposed planetary design, which has a drive and an output, which are arranged in a housing. Furthermore, at least four planetary gear sets are , 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 six preferably designed as a lamellar switching elements or as a form-locking switching elements

Switching elements, comprising brakes and clutches, provided, the selective intervention causes different ratios between the drive and the output, so that preferably at least nine forward gears and one reverse gear can be realized.

The first planetary gear set of the transmission is preferably designed as a positive planetary gear set, wherein the second, third and fourth planetary gear set of the transmission 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. As a result, the ring gear at a fixed web has a direction of rotation opposite to the sun and it results in a negative stationary gear ratio. 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 planet 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.

According to the invention, the sun gear of the first planetary gear set is connected to the third shaft, which is releasably connectable via a first clutch to the drive shaft and can be coupled via a first brake to the housing, wherein the drive shaft via a second clutch with the with the web of the third planetary gear set connected to the fourth wave is detachably connectable, which can be coupled via a second brake to the web of the first planetary gear set, which is coupled to the housing. Furthermore, the drive shaft is connected to the sun gear of the fourth planetary gear set, the eighth shaft being connected to the ring gear of the first planetary gear set, the sun gear of the second planetary gear set and the sun gear of the third planetary gear set, and the fifth shaft to the land of the second planetary gear set and the ring gear connected to the third planetary gear set and via a third clutch with the connected to the ring gear of the fourth planetary gear seventh shaft is detachably connected. The third clutch is preferably arranged radially in the vicinity of the housing.

Further, the sixth shaft is connected to the ring gear of the second planetary gear set and via a fourth clutch, with the output shaft of the transmission detachably connectable, which is connected to the web of the fourth planetary gear set.

Characterized in that the first and second clutch are arranged on the drive shaft of the transmission, the fourth clutch is arranged on the output shaft and the other switching elements are designed as brakes, good accessibility of substantially all switching elements of the transmission is ensured, whereby the switching elements as needed operable switching elements can be executed.

Furthermore, suitable translations especially for passenger cars and an increased total spread of the multi-speed transmission, whereby an improvement in ride comfort and a significant consumption reduction are effected.

In addition, the construction cost is significantly 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, a start with a hydrodynamic converter, an external starting clutch o- perform well with 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 due to low drag and gear losses.

Advantageously, there are low torques on the switching elements and on the planetary gear sets of the multi-speed transmission, whereby the load in the multi-speed transmission is advantageously reduced. In addition, a correspondingly small dimensioning is made possible by the low torques, 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:

Figure 1 is a schematic view of a preferred embodiment of a multi-speed transmission according to the invention; and

FIG. 2 shows an exemplary circuit diagram for a multistage transmission according to FIG. 1.

1 shows a multi-speed transmission according to the invention 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 first planetary gear set P1 is formed in the example shown in Figure 1 as a plus planetary gear, wherein the second, third and fourth planetary gear, P2, P3, P4 are formed as negative planetary gear sets. According to the invention, at least one of Minus planetary gear sets P2, P3, P4 be designed as plus planetary gear set, when the web and Hohlradanbindung exchanged at the same time and the amount of the stationary gear ratio is increased compared to the execution as a minus planetary gear set by 1.

In the embodiment shown, the planetary gear sets P1, P2, P3, P4 axially arranged in the order of the first planetary gear set P1, second planetary gear set P2, third planetary gear set P3, fourth planetary gear set P4. According to the invention, the axial order of the individual planetary gear sets and the arrangement of the switching elements are freely selectable, as long as it allows the binding of the elements of the planetary gear sets.

As can be seen from Figure 1, six switching elements, namely two brakes 03, 04 and four clutches 13, 14, 26, 57 are provided. 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, but can also be designed as a form-locking 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 8, wherein the drive shaft, the first shaft 1 and the output shaft form the second shaft 2 of the transmission.

According to the invention, it is provided in the multistage transmission according to FIG. 1 that the sun gear of the first planetary gear set P1 is connected to the third shaft 3, which can be detachably connected to the drive shaft 1 via a first clutch 13 and can be coupled to the housing G via a first brake 03 , wherein the drive shaft 1 via a second clutch 14 with the connected to the web of the third planetary gear P3 fourth shaft 4 is detachably connectable, which is coupled via a second brake 04 to the web of the first planetary gear P1, which is coupled to the housing G. (Wave 0). Referring to Figure 1, the drive shaft 1 is connected to the sun gear of the fourth planetary gear set P4, wherein the eighth shaft 8 is connected to the ring gear of the first planetary gear P1, the sun gear of the second planetary gear P2 and the sun gear of the third planetary gear set P3; the fifth shaft 5 is connected to the web of the second planetary gear set P2 and the ring gear of the third planetary gear set P3 and detachably connectable via a third clutch 57 with the seventh shaft 7 connected to the ring gear of the fourth planetary gear set P4.

Furthermore, the sixth shaft 6 of the transmission is connected to the ring gear of the second planetary gear set P2 and via a fourth clutch 26, releasably connectable to the output shaft 2 of the transmission, which is connected to the web of the fourth planetary gear set P4.

In the embodiment shown, in particular, the second brake 04 is suitable for a design as a claw switching element, whereby the consumption is significantly improved.

FIG. 2 shows an exemplary circuit diagram of a multistage transmission according to FIG. For each gear three switching elements are closed. The shift scheme, the respective ratios i of the individual grades and the gear ratios to be determined therefrom or increments φ to the next higher gear are exemplified, the value of 9.002 represents the spread of the transmission.

The values for the stationary gear ratios of the first, second, third and fourth planetary gear set P1, P2, P3, P4 are in the example shown in each case 2.550, -3.425, -2.700 and -2.350. From Figure 2 it is seen that in sequential switching mode only one switching element switched on and a switching element must be switched off because two adjacent gear stages use two switching elements together. Further, it will be seen that a large spread is achieved with small gear jumps. The first forward speed results from closing the second brake 04 and the first and third clutches 13, 57, the second forward speed by closing the first and second brakes 03, 04 and the third clutch 57, the third forward speed Closing the second brake 04 and the third and fourth clutches 57, 26, the fourth forward gear by closing the first brake 03 and the third and fourth clutch 57, 26, the fifth forward gear by closing the first, third and fourth clutch 13, 57, 26, the sixth forward gear in the example shown by closing the second, third and fourth clutch 14, 57, 26, the seventh forward gear by closing the first, second and third clutch 13, 14th , 57, the eighth forward gear by closing the first, second and fourth clutches 13, 14, 26 and the ninth forward gear is obtained by closing the first brake 03 and the second and fourth clutches ung 14, 26, wherein the reverse gear by closing the second brake 04 and the first and fourth clutch 13, 26 results.

In addition to the nine forward gears, by closing the first brake 03 and the second and third clutches 14, 57, another gear Z1 can be realized whose gear ratio is between the seventh and eighth forward gear ratios.

Characterized in that the second brake 04 and the first clutch 13 are closed in the first forward gear and in reverse, these switching elements can be used as starting elements.

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.

According to the invention, it is also optionally 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.

In the context of an advantageous development of the invention, the drive shaft 1 can 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 the 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 is 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 a further, not shown embodiment of the invention, on each shaft, preferably on the drive shaft 1 or the output shaft 2, a wear-free brake, such. a hydraulic or electric 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, a power take-off may be provided.

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.

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. REFERENCE CHARACTERS

wave

1 first shaft, drive shaft

second shaft, output shaft

third wave

fourth wave

fifth wave

6 sixth wave

7 seventh wave

8th wave

03 first brake

04 second brake

13 first clutch

14 second clutch

26 fourth clutch

57 third clutch

G housing

P1 first planetary gear set

P2 second planetary gear set

P3 third planetary gear set

P4 fourth planetary gear set

i translation

Φ increment

Claims

claims

1 . 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, 13, 14, 26, 57), comprising brakes (03, 04) and couplings (13, 14, 26, 57 ) whose selective engagement causes different ratios between the drive shaft (1) and the output shaft (2), so that at least nine forward gears and one reverse gear can be realized, wherein the sun gear of the first planetary gear set (P1) is connected to the third shaft (3) , which via a first clutch (13) to the drive shaft (1) is detachably connectable and via a first brake (03) to the housing (G) can be coupled, wherein the drive shaft (1) via a second clutch (14) with the with the bridge of the third planetary gear set (P3 ) Is connected detachably connected via a second brake (04) to the web of the first planetary gear set (P1) which is coupled to the housing (G), wherein the drive shaft (1) with the sun gear the fourth planetary gear set (P4) is connected, wherein the eighth shaft (8) with the ring gear of the first planetary gear set (P1), the sun gear of the second planetary gear set (P2) and the sun gear of the third planetary gear set (P3) is connected and the fifth wave ( 5) to the web of the second planetary gear set (P2) and the ring gear of the third planetary gear set (P3) and via a third clutch (57) with the ring gear of the fourth planetary gear set (P4) connected to the seventh shaft (7) is detachably connectable, wherein the sixth shaft (6) connected to the ring gear of the second planetary gear set (P2) and via a fourth clutch (26) to the output shaft (2) of the transmission is releasably connectable, which with the web of the fourth planet nradsatzes (P4) is connected.

2. Multi-speed transmission according to claim 1, characterized in that the first planetary gear set (P1) is designed as a plus planetary gear, wherein the second, third and fourth planetary gear set (P2, P3, P4) are designed as negative planetary gear sets.

3. Multi-speed transmission according to claim 1, characterized in that the planetary gear sets axially arranged in the order of first planetary gear set (P1), second planetary gear set (P2), third planetary gear set (P3), fourth planetary gear set (P4) are arranged.

4. Multi-step transmission according to claim 1, characterized in that all or individual switching elements of the transmission are designed as demand-actuated switching elements.

5. Multi-step transmission according to one of the preceding claims, characterized in that the second brake (04) is designed as a form-locking switching element.

6. Multi-step transmission according to one of the preceding claims, characterized in that the first forward gear by closing the second brake (04) and the first and third clutch (13, 57), the second forward gear by closing the first and second Brake (03, 04) and the third clutch (57), the third forward gear by closing the second brake (04) and the third and fourth clutch (57, 26), the fourth forward gear by closing the first brake ( 03) and the third and fourth clutches (57, 26), the fifth forward gear by closing the first, third and fourth clutches (13, 57, 26), the sixth forward gear by closing the second, third and fourth clutches (14, 57, 26), the seventh forward speed by closing the first, second and third clutches (13, 14, 57), the eighth forward speed by closing the first, second and fourth clutches (13, 14, 26 ) and that the ninth forward by closing de r first brake (03) and the second and fourth clutches (14, 26), wherein the reverse gear is obtained by closing the second brake (04) and the first and fourth clutches (13, 26) and closing the first brake (03) and the second and third clutch (14, 57), a further gear can be realized, the translation between the translations of the seventh and the eighth forward speed is.