Multi-speed transmission in planetary design

The present invention relates to a multi-speed transmission in planetary design for a vehicle.

As an example, publication DE 10 2007 014 150 A1 discloses a load-shiftable multi-speed transmission. With the multi-speed transmission, the drive shaft is firmly connected through a torsional vibration damper to a first shaft of a first shaft train. A second shaft train arranged parallel to this includes, among other things, the two output shafts designated as shafts. The two shaft trains are connected to each other through three spur gear stages. A first three-shaft planetary gear stage is located on the first shaft train. A second planetary gear stage and a third planetary gear stage are located on the second shaft train. Thus, the multi-speed transmission comprises ten shafts that are connected to each other through three spur gear stages and three planetary gear stages. To shift the eight forward gears and one reverse gear, five shifting elements are necessary. The provided shifting elements are hydraulically operated.

In order to reduce hydraulic losses, the shifting elements are to be arranged in a manner that is easily accessible from the outside. However, with a front-transverse installation of the transmission in a vehicle, only a limited axial installation space is available.

The present invention is subject to a task of providing a multi-speed transmission with the highest possible number of gears and an easy accessibility of the shifting elements, with, at the same time, a good gearing efficiency and a need for axial installation space that is as low as possible. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

The tasks are solved by the characteristics of the transmission embodiments set forth herein.

Accordingly, a load-shiftable multi-speed transmission in planetary design, or a multiple-gear planetary transmission for a vehicle with a housing, is proposed, whereas the drive or the drive shaft, as the case may be, and the output or the output shaft, as the case may be, are arranged in a manner that is axially parallel to each other for a preferred front-transverse installation. The multi-speed transmission in accordance with the invention comprises only nine shafts, three planetary gear sets, and only six shifting elements, in order to realize at least nine forward gears and one reverse gear. In addition, for the coupling of the drive and the output, it is preferable that only two machine elements are provided.

Given the fact that the first shaft, as a drive, is detachably connected, or connectable or connected, to the sun gears of the first and the third planetary gear sets and to the planetary gear carrier of the second planetary gear set and that the second shaft, as an output, is connected, or is detachably connected or connectable, to the first machine element and to the second machine element, a multi-speed transmission in accordance with the invention that enables an actuation of the shifting elements that improves the degree of efficiency and is thus in line with demand arises. The advantageously low number of transmission elements of the multi-speed transmission for a front-transverse design has its transmission elements nested with each other in such a manner that an arrangement that particularly saves axial installation space is enabled. In addition to the improved degree of efficiency, low component stresses and low construction costs arise.

The easy accessibility of the shifting elements may be realized, among other things, on the one hand through the use of brakes as shifting elements and, on the other hand, through the use of clutches as shifting elements, which are preferentially positioned at outside shafts, preferably at the drive and at the output, with the multi-stage transmission in accordance with the invention. Due to the low construction costs, in an advantageous manner, low product costs and a low weight of the multi-speed transmission in accordance with the invention arise.

Within the framework of a possible embodiment of the invention, it can be provided that, as a machine element for the coupling or for the transfer of torque between the drive and the output, at least one spur gear stage or the like, which realizes the transmission ratio for the output differential, is used. Preferably, only two machine elements or spur gear stages are provided. However, other machine elements for the transmission of power, such as chains, belts or the like, may be used.

Viewed in an axial direction, the planetary gear sets are arranged in the order of first planetary gear set, second planetary gear set, and third planetary gear set, whereas it is preferable that three negative planetary gear sets are provided. However, at spots where the binding ability allows it, individual or several negative planetary gear sets may be converted into positive planetary gear sets, if, at the same time, the bar connection or planetary gear carrier connection and the ring gear connection are exchanged, and the amount of the stationary transmission ratio is increased by the value of 1.

As is well-known, a negative planetary gear set features, at the planetary gear carrier, rotatably mounted planetary gears, which mesh with the sun gear and the ring gear of such planetary gear set, such that, with a planetary gear carrier that is held down and a rotating sun gear, the ring gear rotates in a direction opposite to the direction of rotation of the sun gear.

As is well-known, a positive planetary gear set features, at its planetary gear carrier, inner and outer planetary gears that are rotatably mounted and are in a tooth meshing with each other, whereas the sun gear of such planetary gear set meshes with the inner planetary gears, and the ring gear of such planetary gear set meshes with the outer planetary gears, such that, with a planetary gear carrier that is held down and a rotating sun gear, the ring gear rotates in the same direction as the direction of rotation of the sun gear.

Within the framework of a particular embodiment of the invention, it can be provided that several of the planetary gear sets are arranged radially one above the other. For the coupling of the nested planetary gear sets, for example, the ring gear of the inner planetary gear set and the sun gear of the outer planetary gear set are designed as one component. For this purpose, for example, the ring gear of the inner planetary gear set features an inner toothing and an outer toothing, but other embodiments are conceivable. Regardless of the type of coupling, the planetary gear sets that are nested in one another are essentially arranged in one axial plane, such that, in an advantageous manner, axial installation space is saved.

With the multi-speed transmission in accordance with the invention, a hydrodynamic torque converter or a hydrodynamic clutch can be used as the start-up element. It is also conceivable that an additional start-up clutch or an integrated start-up clutch or a start-up brake are used. Furthermore, it is possible that an electric machine or any other power source is arranged at at least one of the shafts. Moreover, at at least one of the shafts, a freewheel is arranged for the housing or for another shaft.

Preferably, with the multi-speed transmission in accordance with the invention, nine forward gears and at least one reverse gear can be shifted by means of the provided shifting elements. However, it is conceivable that, for the fourth forward gear (for example), additional shifting combinations are made possible by combining other shifting elements.

Under term “shifting element,” a shiftable connection between two elements of the transmission is understood, whereas the torque to be transferred between such two elements is transferred by means of the force closure or frictional closure or by means of the form closure. If both elements of the shiftable connection are designed to rotate, the shifting element is referred to as a clutch, and if only one of the two elements of the shiftable connection rotates, the shifting element is referred to as a brake. Moreover, the geometric position and/or order of the individual shifting elements can be freely selected, as long as the binding ability of the elements allows this. In this manner, individual elements may be arbitrarily moved into any position. In addition, to the extent permitted by the external shape, several gear sets can be arranged radially above one another, thus in a nested manner.

Embodiments of a force-fitting shifting element include multi-disk clutches or brakes, band brakes, cone clutches or brakes, electromagnetic clutches, magnetic powder clutches and electro-rheological clutches. Embodiments of a positive-locking shifting element include claw clutches or brakes and tooth clutches.

Thus, in general, both frictional-locking and positive-locking shifting elements may be used as shifting elements. Preferably, given their characteristics, in particular the second shifting element designed as a clutch and the fourth shifting element designed as a clutch can be designed as claw shifting elements, by which significant consumption advantages can be achieved.

In the following, the present invention is explained in more detail based on the drawing. The following is shown:

FIG. 1 is a schematic view of a first design variant of a multi-speed transmission in accordance with the invention;

FIG. 1A is a shifting diagram for the design variant in accordance with FIG. 1 ;

FIG. 2 is a schematic view of a second design variant of the multi-speed transmission;

FIG. 3 is a schematic view of a third design variant of the multi-speed transmission;

FIG. 4 is a schematic view of a fourth design variant of the multi-speed transmission;

FIG. 5 is a schematic view of a fifth design variant of the multi-speed transmission;

FIG. 6 is a schematic view of a sixth design variant of the multi-speed transmission; and

FIG. 7 is a schematic view of an alternative design of the fourth design variant of the multi-speed transmission.

Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

Each of FIGS. 1 to 7 shows an example of a design variant of the multi-speed transmission in planetary design in accordance with the invention, for example as an automatic gearbox or automatic transmission, for a vehicle.

Regardless of the particular design variants, the multi-speed transmission comprises a merely schematically indicated housing 11 , with a first shaft 1 as a drive AN and a second shaft 2 as an output Ab that is arranged in a manner axially parallel to the drive, along with seven additional shafts 3 , 4 , 5 , 6 , 7 , 8 , 9 . Furthermore, a first planetary gear set RS 1 , a second planetary gear set RS 2 , and a third planetary gear set RS 3 are provided, whereas each of the first planetary gear set RS 1 , the second planetary gear set RS 2 and the third planetary gear RS 3 is preferably designed as a negative planetary gear set. For shifting several gears, a first shifting element K 1 designed as a clutch, a second shifting element K 2 designed as a clutch, a third shifting element K 3 designed as a clutch, a fourth shifting element K 4 designed as a clutch, a fifth shifting element B 1 designed as a brake, and a sixth shifting element B 2 designed as a brake are provided. For the coupling or for the transfer of torque between the drive An and the output Ab, two arbitrary machine elements are preferably provided; with the design variants, these are designed, for example, as a first spur gear stage ST 1 and a second spur gear stage ST 2 .

In relation to the design variant in accordance with FIG. 1 , FIGS. 2 to 7 show transmission variants with the same effect, whereas FIG. 7 shows a possible variation of the fourth design variant in accordance with FIG. 4 , with which the shifting elements K 3 and K 4 allocated to the spur gear stages ST 1 and ST 2 are shifted from the output shaft or intermediate shaft, as the case may be, to the main shaft or the drive shaft, as the case may be. The different design variants in accordance with FIGS. 1 to 7 do not functionally differ from the design variants in accordance with FIG. 1 with respect to degree of efficiency, grading, etc.

With respect to the connection options between the provided shafts 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , the provided three planetary gear sets RS 1 , RS 2 , RS 3 , the provided housing 11 and the provided shifting elements K 1 , K 2 , K 3 , K 4 , B 1 , B 2 along with the provided spur gear stages ST 1 , ST 2 , with the term “connectable, it is to be understood that the described elements are detachable (for example, connected by a shifting element), such that the connection is locked with an activated shifting element and open with a non-activated shifting element. The detachable connection may be realized through, in addition to the shifting element, an additional element such as a shaft or the like. With the term “connected,” it is to be understood that the described elements are connected to each other in a manner that is virtually fixed, thus not detachable. A direct or indirect connection (for example, through additional elements) may be realized.

In accordance with the invention, it is provided with the multi-speed transmission that the first shaft 1 is detachably connected, or connectable or connected, as a drive, to the sun gear SR 1 of the first planetary gear set RS 1 , to the sun gear SR 3 of the third planetary gear set RS 3 and to the planetary gear carrier PT 2 of the second planetary gear set RS 2 . Depending on the design variant, the second shaft is detachably connected, or connected or connectable, as output Ab, to the first machine element or to the first spur gear stage ST 1 , as the case may be, and to the second machine element or the second spur gear stage ST 2 , as the case may be.

Regardless of the particular design variants, it is provided that the first shaft 1 is connectable through the first shifting element K 1 designed as a clutch and through the third shaft 3 to the sun gear SR 1 of the first planetary gear set RS 1 , whereas the sun gear SR 1 of the first planetary gear set RS 1 is connectable, through a fifth shifting elements B 1 designed as a brake, to the housing 11 .

Moreover, it is provided with all design variants that two of the three planetary gear sets RS 1 , RS 2 , RS 3 are arranged radially one above the other, and thus lie essentially in one common axial plane. For this purpose, the first planetary gear set is arranged radially inwardly and the second planetary gear set RS 2 is arranged radially outwardly, whereas the ring gear HR 1 of the first planetary gear set RS 1 serves as the connecting link between the two planetary gear sets RS 1 and RS 2 .

With the first design variant in accordance with FIG. 1 , it is provided with the multi-speed transmission in accordance with the invention that the first shaft 1 is connectable through the second shifting element K 2 designed as a clutch and through the eighth shaft 8 to the sun gear SR 3 of the third planetary gear set RS 3 . Furthermore, the first shaft 1 is connectable through the third shifting element K 3 designed as a clutch and through the seventh shaft 7 to the planetary gear carrier PT 2 of the second planetary gear set RS 2 . Moreover, the second shaft 2 is connectable through the fourth shifting element K 4 designed as a clutch and through the ninth shaft 9 to the idler gear 13 of the first spur gear stage ST 1 . In addition, the second shaft 2 is connected to the fixed gear 15 of the second spur gear stage ST 2 .

With the second and third design variant in accordance with FIGS. 2 and 3 , it is provided that the first shaft 1 is connected to the sun gear SR 3 of the third planetary gear set RS 3 . Furthermore, the first shaft 1 is connectable through the third shifting element K 3 designed as a clutch and through the eighth shaft 8 to the planetary gear carrier PT 2 of the second planetary gear set RS 2 . In addition, the second shaft 2 is connectable through the fourth shifting element K 4 designed as a clutch and through the ninth shaft 9 to the idler gear 13 of the first spur gear stage ST 1 . Moreover, the second shaft 2 is connected to the fixed gear 15 of the second spur gear stage ST 2 .

In accordance with FIG. 4 , it is provided with the fourth design variant that the first shaft 1 is connected to the planetary gear carrier PT 2 of the second planetary gear set RS 2 . Furthermore, the first shaft 1 is connectable through the second shifting element K 2 designed as a clutch and through the eighth shaft 8 to the sun gear SR 3 of the third planetary gear set RS 3 . Moreover, the second shaft 2 is connectable through the fourth shifting element K 4 designed as a clutch and through the ninth shaft 9 to the idler gear 13 of the first spur gear stage ST 1 . In addition, the second shaft 2 is connectable through the third shifting element K 3 designed as a clutch and through the seventh shaft 7 to the idler gear 15 A of the second spur gear stage ST 2 .

With the fifth and sixth design variants in accordance with FIGS. 5 and 6 , it is provided that the first shaft 1 is connected to the sun gear SR 3 of the third planetary gear set RS 3 and to the planetary gear carrier PT 2 of the second planetary gear set RS 2 . In addition, the second shaft 2 is connectable through the fourth shifting element K 4 designed as a clutch and through the ninth shaft 9 to the idler gear 13 of the first spur gear stage ST 1 . Furthermore, the second shaft 2 is connectable through the third shifting element K 3 designed as a clutch and through the eighth shaft 8 to the idler gear 15 A of the second spur gear stage ST 2 .

Finally, with the seventh design variant in accordance with FIG. 7 , it is provided with the multi-speed transmission that the first shaft 1 is connected to the planetary gear carrier PT 2 of the second planetary gear set RS 2 . Furthermore, the first shaft 1 is connectable through the second shifting element K 2 designed as a clutch and through the eighth shaft 8 to the sun gear SR 3 of the third planetary gear set RS 3 . Moreover, the second shaft 2 is connected to the fixed gear 13 A of the first spur gear stage ST 1 , and the second shaft 2 is connected to the fixed gear 15 of the second spur gear stage ST 2 .

With the first, second, fourth, fifth and seventh design variants in accordance with FIGS. 1, 2, 4, 5 and 7 , it is provided with the multi-speed transmission that the planetary gear carrier PT 1 of the first planetary gear set RS 1 and the ring gear HR 3 of the third planetary gear set RS 3 are connected through the fourth shaft 4 , whereas the planetary gear carrier PT 1 of the first planetary gear set RS 1 and the ring gear HR 3 of the third planetary gear set RS 3 are connectable, through the fourth shaft 4 and through the sixth shifting element B 2 designed as a brake, to the housing 11 . However, in accordance with FIGS. 3 and 6 , it is provided with the third and sixth design variants that the planetary gear carrier PT 1 of the first planetary gear set RS 1 is connectable through the fourth shaft 4 and through the second shifting element K 2 designed as a clutch and through the seventh shaft 7 to the ring gear HR 3 of the third planetary gear set RS 3 , whereas the planetary gear carrier PT 1 of the first planetary gear set RS 1 and the ring gear HR 3 of the third planetary gear set RS 3 are connectable, through the fourth shaft 4 and through the sixth shifting element B 2 designed as a brake, to the housing 11 .

With the first, third, fourth and sixth design variants in accordance with FIGS. 1, 3, 4 and 6 , it is provided with the multi-speed transmission in accordance with the invention that a fixed gear 12 of a first spur gear stage ST 1 is connectable through the fifth shaft 5 to the ring gear HR 1 of the first planetary gear set RS 1 and to the planetary gear carrier PT 3 of the third planetary gear set RS 3 . In accordance with FIGS. 2 and 5 , it is provided with the second and fifth design variants that a fixed gear 12 of a first spur gear stage ST 1 is connected through the fifth shaft 5 to the ring gear HR 1 of the first planetary gear set RS 1 , whereas the ring gear HR 1 of the first planetary gear set RS 1 is connectable through the fifth shaft 5 and through the second shifting element K 2 designed as a clutch to the planetary gear carrier PT 3 of the third planetary gear set RS 3 . With the seventh design variant in accordance with FIG. 7 , it is finally provided that an idler gear 12 A of a first spur gear stage ST 1 is connectable through the fifth shaft 5 and through the fourth shifting element K 4 designed as a clutch and through the ninth shaft 9 to the ring gear HR 1 of the first planetary gear set RS 1 and to the planetary gear carrier PT 3 of the third planetary gear set RS 3 .

With the first to sixth design variants in accordance with FIGS. 1 to 6 , it is provided that a fixed gear 14 of a second spur gear stage ST 2 is connected through the sixth shaft 6 to the ring gear HR 2 of the second planetary gear set RS 2 . By contrast, with the seventh design variant in accordance with FIG. 7 , it is provided that an idler gear 14 A of a second spur gear stage ST 2 is connectable through the sixth shaft 6 and through the third shifting element K 3 designed as a clutch, and through the seventh shaft 7 , to the ring gear HR 2 of the second planetary gear set RS 2 .

For the six design variants, FIG. 1A shows a shifting diagram or a shifting matrix for the respective transmission variant. In the shifting diagrams, for the realization of the various gears, shifting elements K 1 , K 2 , K 3 , K 4 , B 1 , B 2 to be locked or activated, as the case may be, are shown in table form, whereas a transmission ratio i is indicated for each gear and the respective gear jump φ is indicated between different gears. In addition to the nine forward gears G 1 , G 2 , G 3 , G 4 , G 5 , G 6 , G 7 , G 8 , G 9 and the specified reverse gear R, additional shifting combinations are indicated as alternative fourth forward gears M 1 , M 2 , M 3 . As a whole, it also arises from the shifting diagram that the proposed multi-speed transmission features optimized transmission ratio sequences with low absolute and relative rotational speeds and low torques for the planetary gear sets and shifting elements. In addition, good degrees of toothing efficiency and low drag torques arise from the selected arrangements of the gear sets.

As preferred stationary transmission ratios, a value of approximately i 0 =−2.015 can be used for the first planetary gear set RS 1 , a value of approximately i 0 =−1.700 can be used for the second planetary gear set RS 2 , and a value of approximately i 0 =−1.600 can be used for the third planetary gear set RS 3 . As the stationary transmission ratio, a value of approximately i ST1 =−1.804 is selected for the first spur gear stage ST 1 , and a value of approximately i ST2 =−1.000 is selected for the second spur gear stage ST 2 . Moreover, it arises from the shifting diagram that, for shifting gears, each of the only three shifting elements is locked.

Specifically, it arises from the shifting diagram in accordance with FIG. 1A that, for the realization of the first forward gear G 1 , the second shifting element K 2 designed as a clutch, the fourth shifting element K 4 designed as a clutch, and the sixth shifting element B 2 designed as a brake are locked. For the shifting of the second forward gear G 2 , the second shifting element K 2 designed as a clutch, the fourth shifting element K 4 designed as a clutch and the fifth shifting element B 1 designed as a brake are locked. For the shifting of the third forward gear G 3 , the first shifting element K 1 designed as a clutch, the second shifting element K 2 designed as a clutch and the fourth shifting element K 4 designed as a clutch are locked. For the shifting of the fourth forward gear G 4 , the second shifting element K 2 designed as a clutch, the third shifting element K 3 designed as a clutch and the fourth shifting element K 4 designed as a clutch are locked. For the shifting of the fifth forward gear G 5 , the first shifting element K 1 designed as a clutch, the second shifting element K 2 designed as a clutch and the third shifting element K 3 designed as a clutch are locked. For the shifting of the sixth forward gear G 6 , the second shifting element K 2 designed as a clutch, the third shifting element K 3 designed as a clutch and the fifth shifting element B 1 designed as a brake are locked. For the shifting of the seventh forward gear G 7 , the second shifting element K 2 designed as a clutch, the third shifting element K 3 designed as a clutch and the sixth shifting element B 2 designed as a brake are locked. For the shifting of the eighth forward gear G 8 , the third shifting element K 3 designed as a clutch, the fifth shifting element B 1 designed as a brake and the sixth shifting element B 2 designed as a brake are locked. For the shifting of the ninth forward gear G 9 , the first shifting element K 1 designed as a clutch, the third shifting element K 3 designed as a clutch and the sixth shifting element B 2 designed as a brake are locked. Finally, for the shifting of the reverse gear R, the first shifting element K 1 designed as a clutch, the fourth shifting element K 4 designed as a clutch and the sixth shifting element B 2 designed as a brake are locked.

With respect to the shifting combinations of the alternative fourth forward gears M 1 , M 2 , M 3 , in accordance with the shifting diagram based on FIG. 1A , it is provided that, for the shifting of the alternative fourth forward gear M 1 , the third shifting element K 3 designed as a clutch, the fourth shifting element K 4 designed as a clutch and the fifth shifting element B 1 designed as a brake are locked. For the shifting of the alternative fourth forward gear M 2 , the third shifting element K 3 designed as a clutch, the fourth shifting element K 4 designed as a clutch and the sixth shifting element B 2 designed as a brake are locked. Furthermore, for the shifting of the alternative fourth forward gear M 3 , the first shifting element K 1 designed as a clutch, the third shifting element K 3 designed as a clutch and the fourth shifting element K 4 designed as a clutch are locked.

The different transmission ratios i and the gear jumps φ between different gears with the various design variants can be taken from the corresponding shifting diagram in accordance with FIG. 1A .

Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims.

1 First shaft as a drive

2 Second shaft as an output

3 Third shaft

4 Fourth shaft

5 Fifth shaft

6 Sixth shaft

7 Seventh shaft

8 Eighth shaft

9 Ninth shaft

11 Housing

K 1 First shifting element as a clutch

K 2 Second shifting element as a clutch

K 3 Third shifting element as a clutch

K 4 Fourth shifting element as a clutch

B 1 Fifth shifting element as a brake

B 2 Sixth shifting element as a brake

RS 1 First planetary gear set

RS 2 Second planetary gear set

RS 3 Third planetary gear set

SR 1 Sun gear of the first planetary gear set

PT 1 Planetary gear carrier of the first planetary gear set

HR 1 Ring gear of the first planetary gear set

PT 2 Planetary gear carrier of the second planetary gear set

HR 2 Ring gear of the second planetary gear set

SR 3 Sun gear of the third planetary gear set

PT 3 Planetary gear carrier of the third planetary gear set

HR 3 Ring gear of the third planetary gear set

ST 1 First spur gear stage

ST 2 Second spur gear stage

12 Fixed gear of the first spur gear stage

12 A Idler gear of the first spur gear stage

13 Idler gear of the first spur gear stage

13 A Fixed gear of the first spur gear stage

14 Fixed gear of the second spur gear stage

14 A Idler gear of the second spur gear stage

15 Fixed gear of the second spur gear stage

15 A Idler gear of the second spur gear stage

G 1 First forward gear

G 2 Second forward gear

G 3 Third forward gear

G 4 Fourth forward gear

G 5 Fifth forward gear

G 6 Sixth forward gear

G 7 Seventh forward gear

G 8 Eighth forward gear

G 9 Ninth forward gear

R Reverse gear

M 1 Alternative fourth gear

M 2 Alternative fourth gear

M 3 Alternative fourth gear

i Transmission ratio

i 0 Stationary transmission ratios of the planetary gear sets

i ST1 Stationary transmission ratio of the first spur gear stage

i ST2 Stationary transmission ratio of the second spur gear stage

φ Gear jump