EP2864668A1

EP2864668A1 - Multi-speed gearbox

Info

Publication number: EP2864668A1
Application number: EP13723097.5A
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: US9464693B2; CN104334920A; DE102012210840A1; US20150167793A1; CN104334920B; WO2014000942A1

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, 37, 57, 58, 68), wherein the sun gear of the first planetary gear set (P1) is connected to the seventh shaft (7), which can be connected to the third shaft (3) by means of a first clutch (37), which connects to the sun gear of the second planetary gear set (P2), to the planet carrier of the third planetary gear set (P3) and can be coupled to the housing (G) by means of a first brake (03). The seventh shaft (7) can be connected to the fifth shaft (5) by means of a second clutch (57), which connects to the planet carrier of the third planetary gear set (P3) and can be coupled to the eighth shaft (8) which is connected to the planet carrier of the second planetary gear set (P2) by means of a third clutch (58), which can be connected to the sixth shaft (6) which is connected to the sun gear of the third planetary gear set (P3) and to the sun gear of the fourth planetary gear set (P4) by means of a fourth clutch (68). The input shaft (1) is connected to the planet carrier of the first planetary gear set (P1) and to the ring gear of the second planetary gear set (P2) and the fourth shaft (4) connected to the ring gear of the fourth planetary gear set (P4) can be coupled by means of a second brake (04) to the housing (G) and the output shaft (2) is connected to the ring gear of the first planetary gear set (P1) and 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. Furthermore, to be reduced by means of such transmission of fuel consumption, which can be done on the one hand by reducing the internal transmission losses and on the other hand by operating the engine at the ideal operating point. In order to operate the internal combustion engine at its ideal operating point, it is particularly important to realize small gear jumps with a large gear spread, which results in the increase of the number of gears.

From DE 10 2008 064 1 13 A1 discloses a transmission arrangement of an automatic transmission for a vehicle comprising ten forward gears, which has a first planetary gear, which is designed as a simple planetary gear and a first rotary element, which acts as a fixed element, a second rotary element, the one reduced rotational speed provides, and a third rotary element, which is directly connected to an input shaft and has as input element acts. The known transmission further comprises a second simple planetary gear, which is a fourth rotary member, which is directly connected to the second rotary member, a fifth rotary member which is selectively connected by inserting a first brake with a transmission housing and a sixth rotary member, optionally by inserting a second brake is connected to a transmission housing, wherein a first clutch selectively connects at least two rotational elements of the fourth, fifth and sixth rotational elements. Further, a third of a planetary gear with a single pinion and a planetary gear with double pinion planetary gear is provided, which is a seventh rotary member which is directly connected to the sixth rotary member, an eighth rotary member which is selectively connected by inserting a second clutch to the drive shaft and selectively connected to the transmission housing by inserting a third brake, a ninth rotary element connected to an output shaft, and a tenth rotary element connected to the fourth rotary element by inserting a third clutch, wherein a fourth clutch is interposed between the third Seventh rotary element and the eighth rotary element is arranged.

In transmission concepts with a high number of gears, the problem arises that the number of transmission components and thus the construction costs depending on the number of gears increase greatly. In addition, the internal efficiency of the transmission decreases due to the higher number of transmission components, so that the achievable by the high number of gears consumption optimization is partially compensated.

The present invention has for its object to propose a multi-speed transmission of the type mentioned, which has at least eleven forward gears and a reverse gear and a high spread, in which the construction cost, component load and size are optimized and also the efficiency in terms of drag and Gear losses is improved. 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 in planetary construction, which has a drive and an output, which are arranged in a housing. Furthermore, at least four planetary gear sets, 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 as a lamellae switching elements or executed 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 eleven forward gears and one reverse gear can be realized.

The planetary gear sets 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 seventh shaft, which via a first clutch with the third shaft solves bar is connected, which is connected to the sun gear of the second planetary gear set and the web of the third planetary gear and coupled via a first brake to the housing. The seventh shaft is also detachably connectable via a second clutch with the fifth shaft, which is connected to the ring gear of the third planetary gear and releasably connectable via a third clutch with the eighth shaft connected to the web of the second planetary gear set, wherein the eighth shaft via a fourth clutch with the connected to the sun gear of the third planetary gear set and the sun gear of the fourth planetary gear set sixth shaft of the transmission is detachably connectable.

Furthermore, the drive shaft of the transmission is connected to the web of the first planetary gear set and the ring gear of the second planetary gear set, wherein the fourth shaft connected to the ring gear of the fourth planetary gear set can be coupled to the housing via a second brake and the output shaft of the transmission with the ring gear of the first planetary gear set and the web of the fourth planetary gear set is connected.

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 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 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 transmission can be installed, for example, in front-transverse design or in the context of a standard drive.

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 planetary gear sets P1, P2, P3, P4 are formed in the example shown in Figure 1 as negative planetary gear sets. According to the invention, at least one of the planetary gear sets P1, P2, P3, P4 can be designed as a positive planetary gear set, if at the same time the web and Hohlradanbindung exchanged and the amount of stationary gear ratio is increased by 1 compared to the design as a minus planetary gear.

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.

As can be seen from Figure 1, six switching elements, namely two brakes 03, 04 and four clutches 37, 57, 58, 68 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 at least eleven 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 is provided in the multi-stage transmission according to Figure 1, that the sun gear of the first planetary gear set P1 is connected to the seventh shaft 7, which is detachably connected via a first clutch 37 to the third shaft 3, which with the sun gear of the second planetary gear set P2 and the Web of the third planetary gear set P3 and coupled via a first brake 03 to the housing G can be coupled.

Referring to Figure 1, the seventh shaft 7 via a second clutch 57 to the fifth shaft 5 detachably connected, which is connected to the ring gear of the third planetary gear set P3 and via a third clutch 58 with the with the Web of the second planetary gearset P2 connected eighth shaft 8 is detachably connectable, which is detachably connectable via a fourth clutch 68 with the connected to the sun gear of the third planetary gear P3 and the sun gear of the fourth planetary gear set P4 sixth shaft 6 of the transmission.

Further, the drive shaft 1 is connected to the web of the first planetary gear set P1 and the ring gear of the second planetary gear set P2, wherein the fourth shaft 4 connected to the ring gear of the fourth planetary gear set P4 can be coupled to the housing G via a second brake 04; the output shaft 2 of the transmission is connected to the ring gear of the first planetary gear P1 and the web of the fourth planetary gear set P4.

FIG. 2 shows an exemplary circuit diagram of a multistage transmission according to FIG. For each gear three switching elements are closed. The shift pattern, the respective ratios i of the individual grades and the step to be determined therefrom or increments φ are taken to the next higher gear example, the value 1 1, 095 represents the spread of the transmission.

In the example shown, the values for the stationary gear ratios of the planetary gear sets P1, P2, P3, P4 which are designed as minus planetary gear sets are -1, 91, -1, 60, -1, 60 and -2.96, respectively. 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 gear is obtained by closing the first and second brakes 03, 04 and the fourth clutch 68, the second forward gear by

Closing the second brake 04 and the third and fourth clutches 58, 68, the third forward gear by closing the second brake 04 and the second and fourth clutches 57, 68, the fourth forward gear by closing the second brake 04 and the first and fourth clutch 37, 68, the fifth forward gear by closing the second brake 04 and the first and second clutches 37, 57, the sixth forward gear by closing the second brake 04 and the first and third clutches 37, 58, the seventh forward gear by closing the second brake 04 and the second and third clutches 57, 58, the eighth forward gear executed in the example shown by closing the second, third and fourth clutches 57, 58, 68, the ninth forward gear by closing the first brake 03 and the second and third clutches 57, 58, the tenth forward speed by closing the first brake 03 and the first and second clutches 37, 57 and the eleventh forward gear is obtained by closing the first brake 03 and the second and fourth clutches 57, 68, wherein the reverse gear by closing the first and second brakes 03, 04 and the third clutch 58 results.

Alternatively, the eighth forward gear can be switched by further switching combinations, which are denoted in Figure 2 with 8.1, 8.2 and 8.3. Thus, the eighth forward speed may be achieved by closing the first, second and third clutches 37, 57, 58 or closing the first, second and fourth clutches 37, 57, 68 or closing the first, third and fourth clutches 37, 58, 68 result.

As can also be seen from FIG. 2, the tenth forward gear can be switched by further switching combinations, which are designated in FIG. 2 as 10.1, 10.2 and 10.3. Accordingly, the tenth forward speed can be achieved by closing the first brake 03 and the first and fourth clutches 37, 68, or by closing the first brake 03 and the first and third clutches 37, 58 or by closing the first and second brakes 03, 04 and the first clutch 37 result.

Characterized in that in the first forward gear and in reverse, the first and second brakes 03, 04 are closed, 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 multi-disc clutches, band brakes and / or cone clutches.

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

second shaft, output shaft

third wave

fourth wave

fifth wave

6 sixth wave

7 seventh wave

8th wave

03 first brake

04 second brake

37 first clutch

57 second clutch

58 third clutch

68 fourth 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, 37, 57, 58, 68), comprising brakes (03, 04) and couplings (37, 57, 58, 68 ) whose selective engagement causes different gear ratios between the drive shaft (1) and the output shaft (2), so that at least eleven forward gears and one reverse gear can be realized, wherein the sun gear of the first planetary gear set (P1) with the seventh shaft (7) is connected , which is detachably connectable via a first clutch (37) to the third shaft (3), which connected to the sun gear of the second planetary gear set (P2) and the web of the third planetary gear set (P3) and via a first brake (03) to the Housing (G) can be coupled, w obei the seventh shaft (7) via a second clutch (57) with the fifth shaft (5) is releasably connectable, which connected to the ring gear of the third planetary gear set (P3) and via a third clutch (58) with the with the web of the the second planetary gear set (P2) connected eighth shaft (8) is releasably connectable, which via a fourth clutch (68) with the sun gear of the third planetary gear set (P3) and the sun gear of the fourth planetary gear set (P4) connected to the sixth shaft (6) releasably is connectable, wherein the drive shaft (1) with the web of the first planetary gear set (P1) and the ring gear of the second planetary gear set (P2) is connected and wherein the connected to the ring gear of the fourth planetary gear set (P4) fourth shaft (4) via a second Brake (04) to the housing (G) can be coupled and the output shaft (2) with the ring gear of the first planetary gear set (P1) and the web of the fourth planetary gear set (P4) is connected.

2. Multi-speed transmission according to claim 1, characterized in that the first, second, third and fourth planetary gear set (P1, 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 one of the preceding claims, characterized in that the second brake (04) is designed as a form-locking switching element.

5. Multi-step transmission according to one of the preceding claims, characterized in that the first forward gear by closing the first and second brakes (03, 04) and the fourth clutch (68), the second forward gear by closing the second brake ( 04) and the third and fourth clutch (58, 68), the third forward gear by closing the second brake (04) and the second and fourth clutch (57, 68), the fourth forward gear by closing the second brake ( 04) and the first and fourth clutches (37, 68), the fifth forward gear by closing the second brake (04) and the first and second clutches (37, 57), the sixth forward gear by closing the second brake ( 04) and the first and third clutches (37, 58), the seventh forward gear by closing the second brake (04) and the second and third clutches (57, 58), the eighth forward gear by closing the second, third and fourth clutch (57, 58, 68), the ninth Forward gear by closing the first brake (03) and the second and third clutches (57, 58), the tenth forward gear by closing the first brake (03) and the first and second clutches (37, 57) and that the eleventh forward Gear by closing the first brake (03) and the second and fourth clutch (57, 68) results, wherein the reverse gear by closing the first and second brake (03, 04) and the third clutch (58) results.

6. Multi-speed transmission according to claim 5, characterized in that the eighth forward speed alternatively by closing the first, second and third clutch (37, 57, 58) or by closing the first, second and fourth clutch (37, 57, 68) or by closing the first, third and fourth clutches (37, 58, 68) and that the tenth forward speed alternatively by closing the first brake (03) and the first and fourth clutch (37, 68) or by closing the first brake (03) and the first and third clutch (37, 58 ) or by closing the first and second brakes (03, 04) and the first clutch (37).