WO2012052286A1 - Multi-stage gearbox - Google Patents

Abstract

The multi-stage gearbox having six forward gears and one reverse gear comprises four planetary gear sets (P1, P2, P3, P4), seven rotatable shafts (1, 2, 3, 4, 5, 6, 7) and five shifting elements (03, 04, 05, 06, 16), the sun gear of the planetary gear set (P1) being connected to the sixth shaft (6), which can be removably connected via a clutch (16) to the drive shaft (1) that is connected to the web of the planetary gear set (P2) and to the sun gear of the planetary gear set (P3) and can be coupled to the housing (G) via a first brake (06). The web of the planetary gear set (P1) is connected to the third shaft (3) which is connected to the internal gear of the planetary gear set (P2) and to the internal gear of the planetary gear set (P4) and can be coupled to the housing (G) via a second brake (03). The output shaft (2) is connected to the internal gear of the planetary gear set (P1) and to the web of the planetary gear set (P3), and the sun gear of the planetary gear set (P2) is connected to the fifth shaft (5) that can be coupled to the housing (G) via a third brake (05). The web of the planetary gear set (P4) is connected to the seventh shaft (7) that is connected to the internal gear of the planetary gear set (P3), and the fourth shaft (4) is connected to the sun gear of the planetary gear set (P4) and can be coupled to the housing (G) via a fourth brake (04).

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.

Such an automatic transmission is known for example from DE 199 49 507 A1 of the applicant; In this case, two non-switchable front-gear sets are provided on the output side, the output side generate 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 to switch from a Gear in each case the following higher or lower gear from the two currently operated switching elements only one switching element must be switched on or off.

Using five shift elements, seven forward gears are achieved, nine or ten forward gears using six shift elements.

Furthermore, from DE 29 36 969 A1 a 9-speed multi-speed transmission known; it comprises eight switching elements and four planetary gear sets, one planetary gear set serving as a primary gear and the main gear has a Simpson set and another serving as a reverse gear planetary gear. Further multi-speed transmissions are for example from the

DE 10 2005 010 210 A1 and DE 10 2006 006 637 A1 of 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. 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 intervention 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.

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 Set 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 the second planetary gear set by means of the fifth shaft via a second brake to a housing of the transmission can be coupled. In addition, the seventh shaft with at least one element of the main gearset is constantly connected and coupled via a third brake to the housing of the transmission, the sixth shaft is continuously connected to at least one further element of the main gear and releasably connected 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 may be combined or reduced to form a Ravigneaux set having a common web and a common ring gear.

The present invention has for its object to propose a multi-speed transmission of the type mentioned, which has six forward gears and one reverse gear with sufficient translation, in which the construction cost and size, especially the overall length, or the weight are optimized and also the efficiency in terms the drag and gearing losses is improved. In addition, in the multistage transmission according to the invention, small supporting moments act on the shifting elements. Another object of the invention is to allow easy accessibility of the Scheltelemente of the transmission. 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, seven rotatable shafts - hereinafter referred to as drive shaft, output shaft, third, fourth, fifth, sixth and seventh shaft - and at least five preferably designed as a lamellae switching elements Shift elements, comprising four brakes and a clutch, provided, the selective engagement causes different ratios between the drive and the output, so that preferably six forward gears and one reverse gear can be realized.

The planetary gear sets are preferably arranged axially in the order of the first planetary gearset, second planetary gearset, third planetary gearset, fourth planetary gearset or first planetary gearset, second planetary gearset, fourth planetary gearset, third planetary gearset and are preferably configured as minus planetary gear sets. In other embodiments of the invention, the axial order of the planetary gear sets may be arbitrary.

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, 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 gear ratio translation. According to the invention, the sun gear of the first planetary gear set is connected to the sixth shaft, which is coupled via a first brake to the housing of the transmission and via a coupling with the connected to the web of the second planetary gear set and the sun gear of the third planetary gear set drive shaft of the transmission is connectable, wherein the web of the first planetary gear set is connected to the third shaft, which is connected to the ring gear of the second planetary gear set and the ring gear of the fourth planetary gear set and coupled via a second brake to the housing of the transmission. Further, the output shaft is connected to the ring gear of the first planetary gear set and the land of the third planetary gear set, wherein the sun gear of the second planetary gear set is connected to the fifth shaft, which can be coupled via a third brake to the housing of the transmission.

According to the invention, the web of the fourth planetary gearset is connected to the seventh shaft connected to the ring gear of the third planetary gearset, wherein the fourth shaft is connected to the sun gear of the fourth planetary gearset and can be coupled to the housing of the transmission via a fourth brake.

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.

Advantageously, an easy accessibility of these switching elements is ensured by the execution of four switching elements as brakes, since the brakes are arranged on the transmission housing; Furthermore, the execution of four switching elements results as brakes in energy-saving switching operations, as no rotary transformer are required on the brakes.

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 multi-speed transmission according to the invention, a Approach with a hydrodynamic converter, an external starting clutch o- also to carry out 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 drives with respect to the drag and gear losses.

Furthermore, there are low torques 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, due to the low torques, in particular by the very low torques on the sun gears of the planetary gear sets a correspondingly small dimensions possible, 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: 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 planetary gear sets P1, P2, P3 and P4 are formed in the example shown in Figure 1 as negative planetary gear sets. According to the invention, at least one planetary gear set can be designed as a positive planetary gear set, if at the same time the web and Hohlradanbindung exchanged and the amount of the stationary gear ratio is increased by 1 compared to the design as a minus planetary gear.

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

As shown in Figure 1, five switching elements, namely four brakes 03, 04, 05, 06 and only one clutch 16 are provided. The spatial arrangement of the switching elements can be arbitrary and is limited only by the dimensions and the external shape. The clutch and the brakes of the transmission are preferably designed as Reibschaltelemente or lamellar switching elements.

With these switching elements a selective switching of six forward gears and one reverse gear can be realized. The multi-speed transmission according to the invention has a total of seven rotatable shafts, namely the waves 1, 2, 3, 4, 5, 6 and 7, wherein the drive shaft, the first shaft 1 and the output shaft forms 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 gearset P1 is connected to the sixth shaft 6, which can be released via a clutch 16 to the drive shaft 1 connected to the web of the second planetary gearset P2 and the sun gear of the third planetary gearset P3 connectable and can be coupled via a first brake 06 to the housing G of the transmission; Further, the web of the first planetary gear set P1 is connected to the third shaft 3, which is connected to the ring gear of the second planetary gear set P2 and the ring gear of the fourth planetary gear set P4 and can be coupled via a second brake 03 to the housing G of the transmission. As can be seen from Figure 1, the output shaft 2 is connected to the ring gear of the first planetary gear P1 and the web of the third planetary gear set P3, wherein the sun gear of the second planetary gear set P2 is connected to the fifth shaft 5, via a third brake 05 to the housing G of the transmission can be coupled.

According to the invention, the web of the fourth planetary gear set P4 is connected to the connected to the ring gear of the third planetary gear set P3 seventh shaft 7, wherein the fourth shaft 4 connected to the sun gear of the fourth planetary gear set P4 and a fourth brake 04 to the housing G of the transmission can be coupled.

The first and third brakes 06, 05 and the second and fourth brakes 03, 04 can each be arranged axially next to one another, wherein the single clutch 16 can be arranged axially between the first and the second planetary gear set P1, P2.

FIG. 2 shows an exemplary circuit diagram of a multistage transmission according to FIG. For each gear two switching elements are closed. The shift pattern, the respective ratios of the individual gear ratios i and the determined therefrom gear increments or increments φ are taken to the next higher gear example, the value 7.1 1 1 represents the spread of the transmission.

Typical values for the stationary gear ratios of the planetary gear sets P1, P2, P3 and P4, which are designed as minus planetary gear sets, are -3,000, -3,000, -3,000 and -3,000, respectively. It can be seen from FIG. 2 that in 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. Further, it will be seen that a large spread is achieved with small gear jumps. The first forward gear is obtained by closing the second and fourth brakes 03, 04, the second forward gear by closing the first and fourth brakes 06, 04, the third forward gear by closing the fourth brake 04 and the clutch 16, the fourth forward gear by closing the third and fourth brakes 05, 04, the fifth forward gear by closing the third brake 05 and the clutch 16 and the sixth forward gear is obtained by closing the first and third brakes 06, 05, wherein the reverse gear by closing the second brake 03 and the clutch 16 results.

The fact that the second brake 03 is closed in the first forward gear and in the first reverse gear, this switching element can be used as a starting element.

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 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 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 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 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 switching 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, or form-locking claw switching elements can be 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

1 first shaft, drive shaft

 2 second shaft, output shaft

 3 third wave

 fourth wave

 5 fifth wave

 6 sixth wave

 7 seventh wave

 03 second brake

 04 fourth brake

 05 third brake

 06 first brake

 16 clutch

 P1 first planetary gear set

 P2 second planetary gear set

 P3 third planetary gear set

 P4 fourth planetary gear set

i translation

 Φ increment

 G housing

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 seven rotatable shafts ( 1, 2, 3, 4, 5, 6, 7) and at least five switching elements (03, 04, 05, 06, 16), comprising brakes (03, 04, 05, 06) and a clutch (16) whose selective Intervention causes different ratios between the drive shaft (1) and the output shaft (2), so that six forward gears and one reverse gear can be realized, wherein the sun gear of the first planetary gear set (P1) with the sixth shaft (6) is connected, which via a clutch (16) with the with the web of the second planetary gear set (P2) and the sun gear of the third planetary gear set (P3) connected drive shaft (1) releasably connectable and via a first brake (06) to the housing (G) of the transmission can be coupled, where at the web of the first planetary gear set (P1) is connected to the third shaft (3) connected to the ring gear of the second planetary gear set (P2) and the ring gear of the fourth planetary gear set (P4) and via a second brake (03) to the housing (G) is coupled, wherein the output shaft (2) with the ring gear of the first planetary gear set (P1) and the web of the third planetary gear set (P3) is connected and the sun gear of the second planetary gear set (P2) with the fifth shaft (5) is connected which can be coupled to the housing (G) via a third brake (05), the web of the fourth planetary gear set (P4) being connected to the seventh shaft (7) connected to the ring gear of the third planetary gear set (P3), and the fourth Shaft (4) connected to the sun gear of the fourth planetary gear set (P4) and via a fourth brake (04) to the housing (G) can be coupled. 2. Multi-speed transmission according to claim 1, characterized in that the planetary gear sets (P1, P2, P3, P4) are designed as negative planetary gear sets. 3. Multi-speed transmission according to claim 1 or 2, characterized in that the first forward gear by closing the second and fourth brake (03, 04), the second forward gear by closing the first and fourth brake (06, 04), the third forward speed by closing the fourth brake (04) and the clutch (16), the fourth forward speed by closing the third and fourth brakes (05, 04), the fifth forward speed by closing the third Brake (05) and the clutch (16) and that the sixth forward gear results by closing the first and third brakes (06, 05), wherein the reverse gear by closing the second brake (03) and the clutch (16) results.