Transmission unit

This is a Continuation-In-Part application of pending international patent application PCT/EP2009/006956 filed Aug. 26, 2009 and claiming the priority of German patent application 10 2008 055 626.2 filed Nov. 3, 2008.

The invention relates to a transmission unit for a power train of a motor vehicle including four planetary gear units and six clutch units. It is the principal object to of the invention provide a compact transmission unit with a high number of forward transmission gears.

In a transmission, particularly a motor vehicle transmission, having a first, a second, a third, and a fourth planetary gear unit disposed along a main axis of rotation and having six clutch units providing for nine forward gears to be engaged, a drive unit is connected for rotation with a sun gear of the second planetary gear unit and a fourth planetary carrier of the fourth planetary gear unit and further a power output unit is rotationally fixedly connected to a third planetary carrier of the third planetary gear unit.

A transmission unit of compact design can be provided thereby, which also has a large number of gears with good stepping and sufficient spread.

A “clutch unit” is particularly meant to be a clutch unit and also a brake unit. A “clutch unit” is particularly meant to be a unit which is provided to optionally connect or to separate two clutch elements arranged rotationally in a rotationally fixed manner. A “brake unit” is particularly meant to be a unit which is provided to optionaly connect or separate a rotational clutch element to a fixed unit, particularly a transmission housing, in a rotationally fixed manner.

“A first, a second, a third and a fourth planetary gear unit, which are arranged along a main axis of rotation sequentially” are meant to be in this connection particularly a sequence of four planetary gear units, which are arranged along the main axis of rotation in this sequence, wherein the first planetary gear unit is advantageously facing the drive shaft. For simplification, a “first to fourth planetary wheel carrier”, a “first to fourth sun wheel” and a “first to fourth hollow wheel” shall be meant to be a planetary wheel carrier or a sun wheel or a hollow wheel assigned to the first to fourth planetary gear unit, that is for example that the first planetary wheel carrier is meant to be a planetary wheel carrier of the first planetary gear unit.

Advantageously, at least one of the clutch units is provided to block at least one of the planetary gear units. One of the clutch units is particularly preferred provided to block the second planetary gear unit. A “blocked planetary gear unit” is meant to be a planetary gear unit where the sun wheel, the planetary wheel carrier and the hollow wheel are connected to each other in a rotationally fixed manner. A “blocking of a planetary gear unit” is particularly meant to be that at least two transmission elements of the planetary gear unit are connected to each other in a rotationally fixed manner, wherein the transmission elements are meant to be the sun wheel, the hollow wheel and the planetary wheel carrier. In order to block a planetary wheel carrier, it is basically also conceivable to connected the planetary wheel carrier to planetary wheels guided by the planetary wheel carrier in a rotationally fixed manner, whereby the transmission elements are also connected to each other in a rotationally fixed manner.

Two exemplary embodiments of the invention will be described below with reference to the accompanying drawings.

It is shown in:

FIG. 1 a schematic depiction of the transmission according to the invention,

FIG. 2 exemplary transmission ratios for forward transmission gears of the transmission of FIG. 1 ,

FIG. 3 a shift logic of the transmission of FIG. 1 ,

FIG. 4 a shiftability of the transmission of FIG. 1 ,

FIG. 5 an alternatively designed transmission and in

FIG. 6 a shift logic of the transmission of FIG. 5 .

FIG. 1 shows a transmission designed as a motor vehicle transmission. The transmission has four planetary gear units P 1 a , P 2 a , P 3 a , P 4 a . The first planetary gear unit P 1 a , the second planetary gear unit P 2 a , the third planetary gera unit P 3 a and the fourth planetary gear unit P 4 a are arranged behind one another along a main axis of rotation 10 a . All planetary gear units P 1 a , P 2 a , P 3 a , P 4 a of the transmission have a single planetary wheel set. The transmission has six clutch units S 1 a , S 2 a , S 3 a , S 4 a , S 5 a , S 6 a . These are provided to shift exactly nine forward transmission gears V 1 a , V 2 a , V 3 a , V 4 a , V 5 a , V 6 a , V 7 a , V 8 a , V 9 a . The transmission can however also be operated with only eight forward transmission gears, for example in that the first forward transmission gear V 1 a or the ninth forward transmission gear V 9 a is not shifted.

The transmission is provided to connect a drive engine of a motor vehicle, not shown in detail, to drive wheels of the motor vehicle, not shown in detail. A transmission ratio between the drive engine and the drive wheels can be adjusted by means of the transmission. The transmission can be connected to a hybrid drive module, by means of which the drive torque can be changed. Furthermore, a CVT can be realized by means of the hybrid drive module and the transmission, whereby a transmission can be realized, whose transmission ratio can be adjusted in a stepless manner at least in partial regions.

The transmission has a drive unit 11 a , which is provided to introduce a drive torque into the transmission. A module, not shown in detail, can be connected upstream of the drive unit 11 a , which module shall be provided in particular to provide a start-up functionality. A transducer or a wet start-up clutch is for example conceivable as a module that is connected upstream. The module provided for the start-up can basically also be integrated into the transmission or one of the clutch units S 1 a , S 2 a , S 3 a , S 4 a , S 5 a , S 6 a can for example be used for the start-up.

The transmission further has a power output 12 a , which is provided to divert In a transmission, particularly a motor vehicle transmission, having a first, a second, a third, and a fourth planetary gear unit disposed along a main axis of rotation and having six clutch units providing for nine forward gears to be engaged, a drive unit is connected for rotation with a sun gear of the second planetary gear unit and a fourth planetary carrier of the fourth planetary gear transmission and further a power output unit is rotationally fixedly connected to a third planetary carrier of the third planetary gear unit.a drive torque from the transmission. The power output 12 a is provided to be connected to drive wheels of the motor vehicle. A module, not shown in detail, can be connected downstream of the power output 12 a , by means of which module the torque diverted from the transmission can be distributed to the drive wheels, as for example a differential gear transmission which is provided for a speed compensation between the drive wheels, or an all wheel drive unit, which distributes the drive torque to two different drive axles. The drive unit 11 a and the power output 12 a can basically be arranged relative to each other in an arbitrary manner. A coaxial arrangement on opposite sides of the transmission is thereby particularly advantageous. An arrangement on the same side of the transmission unit is however also conceivable.

The first planetary gear unit P 1 a is arranged on the input side. The first planetary gear unit P 1 a has a single planetary wheel set. The single planetary wheel set comprises a first sun wheel P 11 a , a first hollow wheel P 13 a and a first planetary wheel carrier P 12 a . The planetary wheel carrier P 12 a carries planetary wheels P 14 a on a circular path. The planetary wheels P 14 a cog with the sun wheel P 11 a and with the hollow wheel 13 a . The planetary wheels are mounted rotatably on the planetary wheel carrier P 12 a . The first planetary gear transmission P 1 a has a transmission ratio of −1.970 between the sun wheel P 11 a and the hollow wheel P 13 a with a fixed planetary wheel carrier P 12 a.

The second planetary gear unit P 2 a is arranged centrally on the input side. The second planetary gear unit P 2 a has a single planetary wheel set. The single planetary wheel set comprises a second sun wheel P 21 a , a second hollow wheel P 23 a and a second planetary wheel carrier P 22 a . The planetary wheel carrier P 22 a carries planetary wheels P 24 a on a circular path. The planetary wheels P 24 a cog with the sun wheel P 21 a and with the hollow wheel P 23 a . The planetary wheels are mounted rotatably on the planetary wheel carrier P 22 a . The second planetary gear unit P 2 a has a transmission ratio of −1.658 between the sun wheel P 21 a and the hollow wheel P 23 a with a fixed planetary wheel carrier P 22 a.

The third planetary gear unit P 3 a is arranged centrally on the output side. The third planetary gear unit P 3 a has a single planetary wheel set. The single planetary wheel set comprises a third sun wheel P 31 a , a third hollow wheel P 33 a and a third planetary wheel carrier P 32 a . The planetary wheel carrier P 32 a guides planetary wheels P 34 a on a circular path. The planetary wheels P 34 a cog with the sun wheel P 31 a and with the hollow wheel P 33 a . The planetary wheels are mounted rotatably on the planetary wheel carrier P 32 a . The third planetary gear unit P 3 a has a transmission ratio of −2.548 between the sun wheel P 31 a and the hollow wheel P 33 a with a fixed planetary wheel carrier P 32 a.

The fourth planetary gear unit P 4 a is arranged on the output side. The fourth planetary gear unit P 4 a has a single planetary wheel set. The single planetary wheel set comprises a fourth sun wheel P 41 a , a fourth hollow wheel P 43 a and a fourth planetary wheel carrier P 42 a . The planetary wheel carrier P 42 a guides planetary wheels P 44 a on a circular path. The planetary wheels P 44 a cog with the sun wheel P 41 a and with the hollow wheel P 43 a . The planetary wheels P 44 a are mounted rotatably on the planetary wheel carrier P 42 a . The fourth planetary gear unit P 43 a has a standing transmission ratio of −2.648 between the sun wheel P 41 a and the hollow wheel P 43 a with a fixed planetary wheel carrier P 42 a.

The three clutch units S 3 a , S 4 a , S 6 a are formed as clutch units. They respectively have a first rotatable clutch element S 31 a , S 41 a , S 61 a and a second rotatable clutch element S 32 a , S 42 a , S 62 a . The three clutch units S 3 a , S 4 a , S 6 a are respectively provided to connect their two clutch elements S 31 a , S 32 a , S 41 a , S 42 a , S 61 a , S 62 a in a rotationally fixed manner.

The three clutch units S 1 a , S 2 a , S 5 a are formed as brake units and respectively only have one clutch element S 11 a , S 21 a , S 51 a . The clutch units S 1 a , S 2 a , S 5 a are respectively provided to connect their clutch element S 11 a , S 21 a , S 51 a to a transmission housing in a rotationally fixed manner.

The clutch units S 1 a , S 2 a , S 5 a in the form of brake units are provided on the outside. The clutch units S 3 a , S 4 a , S 6 a in the form of clutch units are arranged on the inside. The clutch units S 1 a , S 2 a , S 3 a , S 4 a include disc packets. The clutch unit S 5 a is designed as a dog clutch unit. It has a synchronising unit, not shown in detail, which can basically also be omitted. The clutch unit S 5 a can however also be formed as a disc packet. The clutch units S 1 a , S 2 a are arranged in the axial direction at the input side from the first planetary gear unit P 1 a . The clutch units S 3 a , S 4 a are arranged in the axial direction between the second planetary gear unit P 2 a and the third planetary gear unit P 3 a . The clutch unit S 5 a is arranged in the axial direction at the height of the third planetary gear unit P 3 a . The clutch unit S 6 a is arranged in the axial direction at the height of the fourth planetary gear unit P 4 a.

The drive unit 11 a is connected to the second sun wheel P 21 a and the fourth planetary wheel carrier P 42 a in a rotationally fixed manner by means of a drive shaft 14 a which is connected to the drive unit 11 a . The first sun wheel P 11 a and the clutch element S 21 a of the second clutch unit S 2 a are connected in a rotationally fixed manner by means of a connection shaft 16 a . The first hollow wheel P 13 a , the clutch element S 42 a of the fourth clutch unit S 4 a , the third sun wheel P 31 a and the fourth sun wheel P 41 a are connected in a rotationally fixed manner by means of a connection shaft 17 a . The clutch element S 11 a of the first clutch unit S 1 a , the second planetary wheel carrier P 22 a , the clutch element S 32 a of the third clutch unit S 3 a and the clutch element S 41 a of the fourth clutch unit S 4 a are connected in a rotationally fixed manner by means of a connection shaft 18 a . The first planetary wheel carrier P 12 a , the second hollow wheel P 23 a and the clutch element S 31 a of the third clutch unit S 3 are connected in a rotationally fixed manner by means of a connection shaft 19 a . The third hollow wheel P 33 a is directly connected to the clutch element S 51 a of the fifth clutch unit S 5 a in a rotationally fixed manner. The fourth hollow wheel P 43 a is directly connected to the clutch element S 61 a of the sixth clutch unit S 6 a in a rotationally fixed manner. The power output unit 12 a is connected in a rotationally fixed manner to the third planetary wheel carrier P 32 a and the clutch element S 62 a of the sixth clutch unit S 6 a by means of a power output shaft 15 a.

The drive shaft 14 a , which is connected to the drive unit 11 a , passes through the four sun wheels P 11 a , P 21 a , P 31 a , P 41 a . The second hollow wheel P 23 a is directly connected to the drive shaft 14 a . For the connection of the fourth planetary wheel carrier P 42 a , it is guided axially and radially between the fourth planetary gear transmission P 4 a and the power output shaft 15 a . The connection shaft 16 a is guided radially to the outside on the axial input side from the first planetary gear unit P 1 a . The connection shaft 17 a surrounds the second planetary gear unit P 2 a . For the connection of the third sun wheel P 31 a and the fourth sun wheel P 41 a , it is guided radially and axially to the inside between the clutch unit S 4 a and the third planetary gear unit P 3 a . The connection shaft 18 a is guided on the inputside to the outside by the connection shaft 16 a . The connection shaft 18 a limits the transmission unit on the input side. It further passes through the first sun wheel P 11 a and is guided to the outside radially and axially between the planetary gear units P 1 a , P 2 a for connecting the second planetary wheel carrier 22 a . For the connection of the clutch element S 42 a , it passes through the second planetary gear unit P 2 a and is guided radially and axially to the outside between the connection shafts 17 a , 19 a . The connection shaft 19 a is guided radially and axially to the outside between the first planetary gear transmission P 1 a and the second planetary gear unit P 2 a . At the output side of the second planetary gear unit P 2 a , the connection shaft 19 a connects the clutch element S 31 a to the clutch unit S 3 a . The power output shaft 15 a is guided axially and radially to the outside between the third planetary gear unit P 3 a and the fourth planetary gear unit P 4 a . It surrounds the fourth planetary gear unit P 4 a and limits the transmission unit on the output side.

Different hybrid drive modules can be combined by means of the transmission unit. A first drive machine of the hybrid drive module can be connected to the drive unit 11 a or the drive shaft 14 a for realizing a starter generator. For realizing a CVT, a further drive machine of the hybrid drive module can additionally be connected to an advantageous shaft of the transmission, as for example to the connection shaft 17 a , which is connected to the third sun wheel P 31 a in a rotationally fixed manner.

The forward transmission gears V 1 a -V 9 a are shifted by means of the clutch units S 1 a , S 2 a , S 3 a , S 4 a , S 5 a , S 6 a (see FIG. 3 ). In the forward transmission gears V 1 a -V 9 a described in the following, respectively at the most three of the clutch units S 1 a , S 2 a , S 3 a , S 4 a , S 5 a , S 6 a are closed, while the remaining clutch units S 1 a , S 2 a , S 3 a , S 4 a , S 5 a , S 6 a are opened. With a shift process from one of the forward transmission gears V 1 a -V 9 a , at the most respectively only two of the clutch units S 1 a , S 2 a , S 3 a , S 4 a , S 5 a , S 6 a are changed. With every shift process from one of the forward transmission gears V 1 a -V 9 a into an adjacent forward transverse transmission gear V 1 a -V 9 a , respectively two clutch units S 1 a , S 2 a , S 3 a , S 4 a , S 5 a , S 6 a which are already closed remain closed.

The second hollow wheel P 23 a and the second planetary wheel carrier can be connected in a rotationally fixed manner by means of the clutch unit S 3 a , whereby the second planetary gear transmission P 2 a can be blocked by means of the clutch unit S 3 a . The first planetary wheel carrier P 12 a and the second hollow wheel P 23 a and the first hollow wheel P 13 a and the second planetary wheel carrier P 22 can be connected in a rotationally fixed manner by means of the clutch units S 3 a , S 4 a . As the second planetary gear transmission P 2 a is blocked in this case, the first planetary gear transmission is thereby also blocked and connected in a rotationally fixed manner to the second planetary gear transmission P 2 a.

The first forward transmission gear V 1 a has a transmission ratio i 1 a of 5.525 between the drive unit 11 a and the power output unit in this embodiment. The first forward transmission gear V 1 a is formed by closing the clutch units S 2 a , S 4 a , S 5 a . The clutch unit S 2 a connects the first sun wheel P 11 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 4 a connects the second planetary wheel carrier P 22 a to the first hollow wheel P 13 a and the third sun wheel P 31 a in a rotationally fixed manner. The clutch unit S 5 a connects the third hollow wheel P 33 a to the transmission housing 13 a in a rotationally fixed manner.

The second sun wheel P 21 a rotates with a same speed as the drive unit 11 a . The second planetary wheel carrier P 22 a rotates with a same speed as the first hollow wheel P 13 a . The second hollow wheel P 23 a rotates with a same speed as the first hollow wheel P 12 a . As the first sun wheel P 11 a is fixed, a speed ratio between the first planetary wheel carrier P 12 a and the first sun wheel P 11 a is defined by means of the standing transmission ratio of the first planetary gear transmission P 1 a , whereby a speed ratio between the second hollow wheel P 23 a and the second planetary wheel carrier P 22 a is also defined. A speed of the second planetary wheel carrier P 22 a is thus defined by the speed of the second sun wheel P 21 a and the standing transmission ratio of the first planetary gear unit P 1 a . The third sun wheel P 31 a has the same speed as the second planetary wheel carrier P 22 a . As the third hollow wheel P 33 a is fixed, a speed of the third planetary wheel carrier P 32 a is defined by the speed of the third sun wheel P 31 a and the standing transmission ratio of the third planetary gear unit P 3 a . The power output unit 12 a has the same speed as the second planetary wheel carrier P 22 a . A power flow for the first transmission gear V 1 an is introduced via the second planetary gear unit P 2 a and split via the clutch unit S 4 a . A part of the power flow is fed back to the second planetary gear unit P 2 a via the first planetary gear transmission P 1 a . A further part of the power flow is diverted via the third planetary gear transmission P 3 a.

The second forward transmission gear V 2 a has a transmission ratio i 2 a of 3.548 between the drive unit 11 a and the power output unit 12 a in this embodiment. The second forward transmission gear V 2 a is formed by closing the clutch units S 3 a , S 4 a , S 5 a . The clutch unit S 3 a connects the second planetary wheel carrier P 22 a to the second hollow wheel P 23 a and the first planetary wheel carrier P 12 a in a rotationally fixed manner. The clutch unit S 4 a connects the second planetary wheel carrier P 22 a to the third sun wheel P 31 a in a rotationally fixed manner. The clutch unit S 5 a connects the third hollow wheel P 33 a to the transmission housing 13 a in a rotationally fixed manner.

As the second planetary wheel carrier P 22 a is connected to the second hollow wheel P 23 a in a rotationally fixed manner, the second planetary gear unit P 2 a is blocked. The second planetary wheel carrier P 22 a thus has a same speed as the drive unit 11 a . As the second planetary wheel carrier P 22 a is connected to the third sun wheel P 31 a in a rotationally fixed manner, the third sun wheel P 31 a also has the same speed as the drive unit 11 a . The third hollow wheel P 33 a is fixed, whereby the speed of the drive unit 11 a and the standing transmission ratio of the third planetary gear transmission P 3 a is defined. The power output unit 12 a has the same speed as the third planetary wheel carrier P 32 a . A power flow for the second forward transmission gear V 2 a is introduced via the second planetary gear unit P 2 a and is diverted via the third planetary gear unit P 3 a.

The third forward transmission gear V 3 a has a transmission ratio i 3 a of 2.355 between the drive unit 11 a and the power output unit 12 a in this embodiment. The third forward transmission gear V 3 a is formed by closing the clutch units S 2 a , S 3 a , S 5 a . The clutch unit S 2 a connects the first sun wheel P 11 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 3 a connects the second planetary wheel carrier P 22 a to the second hollow wheel P 23 a and the first planetary wheel carrier P 12 a in a rotationally fixed manner. The clutch unit S 5 a connects the third hollow wheel P 33 a to the transmission housing 13 a in a rotationally fixed manner.

The second sun wheel P 21 a has a same speed as the drive unit 11 a . As the second planetary gear unit P 2 a is blocked, the first planetary wheel carrier P 12 a , which is connected to the second hollow wheel P 23 a in a rotationally fixed manner, also has the same speed as the drive unit 11 a . As the first sun wheel P 11 a is fixed, a speed of the first hollow wheel P 13 a is defined by the speed of the drive unit 11 a and the standing transmission ratio of the first planetary gear unit P 1 a . The third sun wheel P 31 a is connected to the first hollow wheel P 13 a in a rotationally fixed manner and thus has the same speed as the first hollow wheel P 13 a . The third hollow wheel P 33 a is fixed, whereby a speed of the third planetary wheel carrier P 32 a , which is connected to the power output unit P 11 a in a rotationally fixed manner, is defined by the standing transmission ratio of the third planetary gear unit P 3 a and the speed of the third sun wheel P 31 a . A power flow for the third forward transmission gear V 3 a is introduced via the second planetary gear unit P 2 a , guided further via the first planetary gear unit P 1 a and is diverted again via the third planetary gear unit P 3 a.

The fourth forward transmission gear V 4 a has a transmission ratio i 4 a of 1.698 between the drive unit 11 a and the power output unit 12 a in this embodiment. The fourth forward transmission gear V 4 a is formed by closing the clutch units S 2 a , S 5 a , S 6 a . The clutch unit S 2 a connects the first sun wheel P 11 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 5 a connects the third hollow wheel P 33 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 6 a connects the fourth hollow wheel P 43 a to the power output unit 12 a in a rotationally fixed manner.

The fourth planetary wheel carrier P 42 a rotates with the same speed as the drive unit 11 a . The fourth sun wheel P 41 a is connected to the third sun wheel P 31 a in a rotationally fixed manner. The fourth hollow wheel P 43 a is connected to the third planetary wheel carrier P 32 a in a rotationally fixed manner. As the third hollow wheel P 33 a is fixed, a speed ratio between the third sun wheel P 31 a and the third planetary wheel carrier P 32 a , which is the same as a speed ratio between the fourth sun wheel P 41 a and the fourth hollow wheel P 43 a , is defined by means of the standing transmission ratio of the third planetary gear unit P 3 a . A speed of the power output unit 12 a , which is the same as the speed of the fourth hollow wheel P 43 a , is thus defined by the standing transmission ratio of the fourth planetary gear unit P 4 a , the speed ratio between the fourth sun wheel P 41 a and the fourth hollow wheel P 43 a and the speed of the drive unit 11 a . A power flow for the fourth forward transmission gear V 4 a is introduced via the fourth planetary gear unit and split via the clutch unit S 6 a . A part of the power flow is fed back to the fourth planetary gear unit P 4 a via the third planetary gear unit P 3 a . A further part of the power flow is diverted directly.

The fifth forward transmission gear V 5 a has a transmission ratio i 5 a of 1.236 between the drive unit 11 a and the power output unit 12 a in this embodiment. The fifth forward transmission gear V 5 a is formed by closing the clutch units S 2 a , S 3 a , S 6 a . The clutch unit S 2 a connects the first sun wheel P 11 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 3 a connects the second planetary wheel carrier P 22 a to the second hollow wheel P 23 a and the first planetary wheel carrier P 12 a in a rotationally fixed manner. The clutch unit S 6 a connects the fourth hollow wheel P 43 a to the power output unit 12 a in a rotationally fixed manner.

The second sun wheel P 21 a P 21 a has a same speed as the drive unit 11 a . As the the second planetary wheel carrier P 22 a is connected to the second hollow wheel P 23 a in a rotationally fixed manner, the second planetary gear unit P 2 a is blocked, whereby the second planetary wheel carrier P 22 a and the second hollow wheel P 23 a also have the same speed as the drive unit 11 a . The first sun wheel is fixed. The first planetary wheel carrier P 12 a , which is connected to the second hollow wheel P 23 a in a rotationally fixed manner, has the same speed as the drive unit 11 a . A speed of the first hollow wheel P 13 a is thus defined by the standing transmission ratio of the first planetary gear unit P 1 a and the speed of the drive unit 11 a . The fourth planetary wheel carrier P 42 a also has the same speed as the drive unit 11 a . The fourth sun wheel P 41 a has the same speed as the first hollow wheel P 13 a . A speed of the fourth hollow wheel P 43 a , which is connected to the power output unit 12 a in a rotationally fixed manner, is defined by means of the speed of the drive unit 11 a , the speed of the fourth sun wheel P 41 a and the standing transmission ratio of the fourth planetary gear unit P 4 a . A power flow for the fifth transmission gear V 5 a is introduced via the fourth planetary gear unit P 4 a and is split. A part of the power flow is fed back to the drive unit 11 a via the first planetary gear unit P 1 a and the second planetary gear unit P 2 a . A further part of the power flow is diverted again via the fourth planetary gear unit P 4 a.

The sixth forward transmission gear V 6 a has a transmission ratio i 6 a of 1.000 between the drive unit 11 a and the power output 12 a in this embodiment. It is formed as a direct gear. The sixth forward transmission gear V 6 a is formed by closing the clutch units S 3 a , S 4 a , S 6 a . The clutch unit S 3 a connects the second planetary wheel carrier P 22 a to the second hollow wheel P 23 a and the first planetary wheel carrier P 12 a in a rotationally fixed manner. The clutch unit S 4 a connects the second planetary wheel carrier P 22 a to the fourth sun wheel P 41 a in a rotationally fixed manner. The clutch unit S 6 a connects the fourth hollow wheel P 43 a to the power output 12 a in a rotationally fixed manner.

As the second planetary wheel carrier P 22 a is connected to the second hollow wheel P 23 a in a rotationally fixed manner, the second planetary gear unit P 2 a is blocked. As the second sun wheel P 21 a has a same speed as the drive unit 11 a , the second planetary wheel carrier P 22 a and the fourth sun wheel P 41 a also have the same speed as the drive unit 11 a . The fourth planetary wheel carrier P 42 a , which is connected to the drive unit 11 a in a rotationally fixed manner, also has the same speed as the drive unit 11 a , whereby the fourth hollow wheel P 43 a also has the same speed as the drive unit 11 a . A power flow for the sixth transmission gear V 6 a is introduced via the fourth planetary gear unit P 4 a and is split. A part of the power flow is fed back to the drive unit 11 a via the second planetary gear unit P 2 a . A further part of the power flow is diverted again via the fourth planetary gear unit P 4 a.

The seventh forward transmission gear V 7 a has a transmission ratio i 7 a of 0.881 between the drive unit 11 a and the power output 12 a in this embodiment. The seventh forward transmission gear V 7 a is formed by closing the clutch units S 2 a , S 4 a , S 6 a . The clutch unit S 2 a connects the first sun wheel P 11 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 4 a connects the second planetary wheel carrier P 22 a to the fourth sun wheel P 41 a in a rotationally fixed manner. The clutch unit S 6 a connects the fourth hollow wheel P 43 a to the power output 12 a in a rotationally fixed manner.

As the first sun wheel P 11 a is fixed, a speed ratio between the first planetary wheel carrier P 12 a and the first hollow wheel P 13 a and thus also between the second hollow wheel P 23 a and the second planetary wheel carrier P 22 a by the standing transmission ratio of the first planetary gear unit P 1 a . A speed of the fourth sun wheel P 41 a , which is the same as a speed of the second hollow wheel P 23 a , is thus defined by the speed ratio between the first planetary wheel carrier P 12 a and the first hollow wheel P 13 a and a speed of the drive unit 11 a . A speed of the fourth hollow wheel P 43 a is defined by the speed of the fourth sun wheel P 41 a , the speed of the drive unit 11 a and the standing transmission ratio of the fourth planetary gear unit P 4 a . A power flow for the seventh forward transmission gear V 7 a is introduced via the fourth planetary gear unit P 4 a and is split. A part of the power flow is fed back to the drive unit 11 a via the second planetary gear unit P 2 a and the first planetary gear unit P 1 a . A further part of the power flow is diverted via the fourth planetary gear unit P 4 a.

The eighth forward transmission gear V 8 a has a transmission ratio i 8 a of 0.726 between the drive unit 11 a and the power output 12 a in this embodiment. The eighth forward transmission gear V 8 a is formed by closing the clutch units S 1 a , S 4 a , S 6 a . The clutch unit S 1 a connects the second planetary wheel carrier P 22 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 4 a connects the fourth sun wheel P 41 a to the second planetary wheel carrier P 22 a and thus to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 6 a connects the fourth hollow wheel P 43 a to the power output 12 a in a rotationally fixed manner.

The fourth sun wheel P 41 a is fixed. The fourth planetary wheel carrier P 42 a , which is connected to the drive unit 11 a in a rotationally fixed manner has a same speed as the drive unit 11 a . A speed of the fourth hollow wheel P 43 a and thus a speed of the power output unit 12 a are defined by the speed of the drive unit 11 a and the standing transmission ratio of the fourth planetary gear unit P 4 a . A power flow for the eighth forward transmission gear V 8 is introduced and diverted via the fourth planetary gear unit P 4 b.

The ninth forward transmission gear V 9 a has a transmission ratio i 9 a of 0.581 between the drive unit 11 a and the power output 12 a in this embodiment. The ninth forward transmission gear V 9 b is formed by closing the clutch units S 1 a , S 2 a , S 6 a . The clutch unit S 1 a connects the second planetary wheel carrier P 22 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 2 a connects the first sun wheel P 11 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 6 a connects the fourth hollow wheel P 43 a to the power output 12 a in a rotationally fixed manner.

The second planetary wheel carrier P 22 a is fixed. The second sun wheel P 21 a has a same speed as the drive unit 11 a . A speed of the second hollow wheel P 23 a is defined by the speed of the drive unit 11 a and the standing transmission ratio of the second planetary gear unit P 2 a . The first planetary wheel carrier P 12 a has the same speed as the second hollow wheel P 23 a . The first sun wheel P 11 a is fixed. A speed of the first hollow wheel P 13 a is defined by the speed of the second hollow wheel P 23 a and the standing transmission ratio of the first planetary gear unit P 1 a . The speed of the fourth sun wheel P 41 a is the same as the speed of the first hollow wheel P 13 a . The fourth hollow wheel P 42 a has a same speed as the drive unit 11 a . A speed of the fourth hollow wheel P 43 a , which is connected to the power output 12 a in a rotationally fixed manner, is defined by the speed of the second hollow wheel P 23 a , the standing transmission ratio of the fourth planetary gear unit P 4 a and the speed of the drive unit 11 a . A power flow for the ninth forward transmission gear V 9 a introduced via drive unit 11 a is split before the first planetary gear unit P 1 a . A first part of the power flow is guided to the fourth planetary gear unit P 4 a via the second planetary gear unit P 2 a and the first planetary gear unit P 1 a . A second part of the power flow is guided directly to the fourth planetary gear unit P 4 a . The power flow is combined again and diverted by means of the fourth planetary gear unit P 4 a.

The reverse transmission gear R 1 a has a transmission ratio i R a of −3.905 between the drive unit 11 b and the power output unit 12 a in this embodiment. The reverse transmission gear R 1 a is formed by closing the clutch units S 1 a , S 2 a , S 5 a . The clutch unit S 1 a connects the second planetary wheel carrier P 22 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 2 a connects the first sun wheel P 11 a to the transmission housing 13 a in a rotationally fixed manner. The clutch unit S 5 a connects the third hollow wheel P 33 a to the transmission housing 13 a in a rotationally fixed manner.

The second planetary wheel carrier P 22 a is fixed. The second sun wheel P 21 a has a same speed as the drive unit 11 a . A speed of the second hollow wheel P 23 a is defined by the speed of the drive unit 11 a and the standing transmission ratio of the second planetary gear unit P 2 a . The first planetary wheel carrier P 12 a has the same speed as the second hollow wheel P 23 a . The first sun wheel P 11 a is fixed. A speed of the first hollow wheel P 13 a is defined by the speed of the second hollow wheel P 23 a and the standing transmission ratio of the first planetary gear unit P 1 a . The speed of the third sun wheel P 31 a is the same as the speed of the first hollow wheel P 13 a . The third hollow wheel P 33 a is fixed. A speed of the third planetary wheel carrier P 32 a , which is connected to the power output 12 a in a rotationally fixed manner, is defined by the speed of the first hollow wheel P 13 a and the standing transmission ratio of the third planetary gear unit P 3 a . A power flow for the reverse transmission gear R 1 a is introduced via the second planetary gear transmission P 2 a , guided to the third planetary gear unit P 3 a via the first planetary gear unit P 1 a , and is diverted again via the third planetary gear unit P 3 a.

A progressive ratio φ 1/2 a between the first and the second forward transmission gear V 1 a , V 2 a is 1.557. A progressive ratio φ 2/3 a between the second and the third forward transmission gear V 2 a , V 3 a is 1.506. A progressive ratio φ 3/4 a between the third and the fourth forward transmission gear V 3 a , V 4 a is 1 .387. A progressive ratio φ 4/5 a between the fourth and the fifth forward transmission gear V 4 a , V 5 a is 1.374. A progressive ratio φ 5/6 a between the fifth and the sixth forward transmission gear V 5 a , V 6 a is 1.236. A progressive ratio φ 6/7 a between the sixth and the seventh forward transmission gear V 6 a , V 7 a is 1.135. A progressive ratio φ 7/8 a between the seventh and the eighth forward transmission gear V 7 a , V 8 a is 1.214. A progressive ratio φ 8/9 a between the eighth and the ninth forward transmission gear V 8 a , V 9 a is 1.249. A total spread of the transmission unit between the first forward transmission gear V 1 a and the ninth forward transmission gear V 9 a is about 9.5. A spread between the first forward transmission gear V 1 a and the eighth forward transmission gear V 8 a is about 7.6. A spread between the second forward transmission gear V 2 a and the ninth forward transmission gear V 9 a is about 6.1 (see FIG. 2 ). The transmission unit can basically also be used as an eight gear transmission.

A maximum speed factor for the planetary gear unit P 1 a , P 2 a , P 3 a , P 4 a is about 2.7. A maximum speed factor for the planetary gear units P 1 a , P 2 a , P 3 a , P 4 a is about 3.3 in the forward transmission gear V 9 a . The speed factor for the planetary gear units P 1 a , P 2 a , P 3 a , P 4 a describes a ratio between a speed of the drive unit 11 a and a maximum speed, which occurs at the sun wheels P 11 a , P 21 a , P 31 a , P 41 a , the hollow wheels P 13 a , P 23 a , P 33 a , P 43 a or the planetary wheel carriers P 12 a , P 22 a , P 32 a , P 42 a in one of the forward transmission gears V 1 a -V 9 a. A maximum speed factor for the planetary wheels P 14 a , P 24 a , P 34 a , P 44 a is about 3.0 in the forward transmission gears V 1 a -V 8 a and about 3.3 in the ninth forward transmission gear V 9 a . A maximum speed of the drive unit 11 a and thus a speed of the planetary wheels P 14 a , P 24 a , P 34 a , P 44 a can be limited in the ninth forward transmission gear V 9 a.

A maximum torque factor is about 5.5 for the forward transmission gears V 1 a -V 9 a . The torque factor describes a ratio between between a drive torque applied at a drive unit 11 a and a maximum torque occurring at the sun wheels P 11 a , P 21 a , P 31 a , P 41 a , the hollow wheels P 13 a , P 23 a , P 33 a , P 43 a or the planetary wheel carriers P 12 a , P 22 a , P 32 a , P 42 a . The maximum torque factor for the forward transmission gears V 1 a -V 9 a is achieved in the first forward transmission gear V 1 a.

A shiftability of the forward transmission gears V 1 a -V 9 a is shown in FIG. 4 . The forward transmission gears V 2 a , V 3 a , V 4 a , V 7 a can be shifted starting with the first forward transmission gear V 1 a . The forward transmission gears V 1 a , V 3 a , V 6 a can be shifted starting with the second forward transmission gear V 2 a . The forward transmission gears V 1 a , V 2 a , V 4 a , V 5 a can be shifted starting with the third forward transmission gear V 3 a . The forward transmission gears V 4 a , V 5 a , V 7 a , V 9 a can be shifted starting with the fourth forward transmission gear V 4 a . The forward transmission gears V 3 a , V 4 a , V 6 a , V 7 a , V 9 a can be shifted starting with the fifth forward transmission gear V 5 a . The forward transmission gears V 2 a, V 5 a , V 7 a , V 8 a can be shifted starting with the sixth forward transmission gear V 6 a . The forward transmission gears V 1 a , V 4 a , V 5 a , V 6 a , V 8 a , V 9 a can be shifted starting with the seventh forward transmission gear V 7 a . The forward transmission gears V 6 a , V 7 a , V 9 a can be shifted starting with the eighth forward transmission gear V 8 a . The forward transmission gears V 4 a , V 5 a , V 7 a , V 8 a can be shifted starting with the ninth forward transmission gear V 9 a.

In FIGS. 5 to 6 is shown a further embodiment of the invention. For distinguishing the embodiments, the letter “a” is replaced in the reference numerals of the embodiment in FIGS. 1 and 4 by the letter b in the reference numerals of the embodiments in FIGS. 5 to 6 . The following description is essentially restricted to differences between the embodiments. With regard to the same components, characteristics and functions, one can refer to the description and/or the drawings of the embodiment in FIGS. 1 to 4 .

FIG. 5 shows a transmission designed as a motor vehicle transmission. The transmission has four planetary gear units P 1 b , P 2 b , P 3 b , P 4 b . The first planetary gear unit P 1 b , the second planetary gear unit P 2 b , the third planetary gear unit P 3 b and the fourth planetary gear unit P 4 b are arranged behind each other along a main axis of rotation 10 b . The transmission has six clutch units S 1 b , S 2 b , S 3 b , S 4 b , S 5 b , S 6 b . These are provided to shift exactly nine forward transmission gears V 1 b , V 2 b , V 3 b , V 4 b , V 5 b , V 6 b , V 7 b , V 8 b , V 9 b . The transmission can however also be operated with only eight forward transmission gears, for example in that the first forward transmission gear V 1 b or the ninth forward transmission gear V 9 b is not shifted.

The first planetary gear unit P 1 b is arranged on the input side. The first planetary gear unit P 1 b has a single planetary wheel set. The single planetary wheel set comprises a first sun wheel P 11 b , a first hollow wheel P 13 b and a first planetary wheel carrier P 12 b . The first planetary gear unit P 1 b has a standing transmission ratio of −1.970 between the sun wheel P 11 b and the hollow wheel P 13 b with a fixed planetary wheel carrier P 12 b.

The second planetary gear unit P 2 b is arranged centrally on the input side. The second planetary gear unit P 2 b has a single planetary wheel set. The single planetary wheel set comprises a second sun wheel P 21 b , a second hollow wheel P 23 b and a second planetary wheel carrier P 22 b . The second planetary gear unit P 2 b has a standing transmission ratio of −1.654 between the sun wheel P 21 b and the hollow wheel P 23 b with a fixed planetary wheel carrier P 22 b.

The third planetary gear unit P 3 b is arranged centrally on the output side. The third planetary gear unit P 3 b has a single planetary wheel set. The single planetary wheel set comprises a third sun wheel P 31 b , a third hollow wheel P 33 b and a third planetary wheel carrier P 32 b . The third planetary gear unit P 3 b has a standing transmission ratio of −2.556 between the sun wheel P 31 b and the hollow wheel P 33 b with a fixed planetary wheel carrier P 32 b.

The fourth planetary unit P 4 b is arranged on the output side. The fourth planetary gear unit P 4 b has a single planetary wheel set. The single planetary wheel set comprises a fourth sun wheel P 41 b , a fourth hollow wheel P 43 b and a fourth planetary wheel carrier P 42 b . The fourth planetary gear unit P 4 b as a standing transmission ratio of −2.644 between the sun wheel P 41 b and the hollow wheel P 43 b with a fixed planetary wheel carrier P 42 b.

The three clutch units S 3 b , S 4 b , S 6 b formed as clutch units respectively have one first rotatable clutch element S 31 b , S 41 b , S 61 b and a second rotatable clutch element S 32 b , S 42 b , S 62 b which can be connected to each other in a rotationally fixed manner by means of the corresponding clutch units S 3 b , S 4 b , S 6 b . The three clutch units S 1 b , S 2 b , S 5 b formed as brake units respectively only have one clutch element S 11 b , S 21 b , S 51 b , which can be connected to a transmission housing 13 b in a rotationally fixed manner by means of the corresponding clutch units S 1 b , S 2 b , S 5 b.

The clutch units S 1 b , S 2 b , S 3 b , S 5 b are arranged on the outside. The clutch units S 4 b , S 6 b are designed as lying on the inside. The clutch units S 1 b , S 2 b , S 3 b , S 6 b are in the form of disc packets. The clutch unit S 5 b is in the form of a dog clutch unit. It has a synchronising unit, not shown in detail, which can basically also be omitted. The clutch unit S 5 b can however also in the form of a disc packet. The clutch units S 3 b , S 1 b , S 2 b are arranged in the axial direction at the input side from the first planetary gear unit P 1 b in this sequence. The clutch unit S 4 b is arranged in the axial direction between the second planetary gear unit P 2 b and the third planetary gear unit P 3 b . The clutch unit S 5 b is arranged in the axial direction at the level of the fourth planetary gear unit P 3 b . The clutch unit S 6 b is arranged in the axial direction at the level of the fourth planetary gear unit P 4 b.

The drive unit 11 b is connected to the second sun wheel P 21 b , the fourth planetary wheel carrier P 42 b and the first clutch element S 31 b of the third clutch unit S 3 b in a rotationally fixed manner by means of a drive shaft 14 b which is connected to the drive unit 11 b . The first sun wheel P 11 b and the clutch element S 21 b of the second clutch unit S 2 b are connected in a rotationally fixed manner by means of a connection shaft 16 b . The first hollow wheel P 13 b , the clutch element S 42 b of the fourth clutch unit S 4 b , the third sun wheel 31 b and the fourth sun wheel P 41 b are connected in a rotationally fixed manner by means of a connection shaft 17 b . The clutch element S 32 b of the third clutch unit S 3 b , the clutch element S 11 b of the first clutch unit S 1 b , the second planetary wheel carrier P 22 b and the clutch element S 41 b of the fourth clutch unit S 4 b are connected in a rotationally fixed manner by means of a connection shaft 18 b . The first planetary wheel carrier P 12 b and the second hollow wheel P 23 b are connected in a rotationally fixed manner by means of a connection shaft 19 b . The third hollow wheel P 33 b is directly connected to the clutch element S 51 b of the fifth clutch unit S 5 b in a rotationally fixed manner. The fourth hollow wheel P 43 b is directly connected to the clutch element S 61 b of the sixth clutch unit S 6 b in a rotationally fixed manner. The power output unit 12 b is connected in a rotationally fixed manner to the third planetary wheel carrier P 32 b and the clutch element S 62 b of the sixth clutch unit S 6 b by means of a power output shaft 15 b.

The drive shaft 14 b , which is connected to the drive unit 11 b , passes through the four sun wheels P 11 b , P 21 b , P 31 b , P 41 b . For the connection of the clutch element S 31 b , it is guided axially to the outside at the input side. The drive shaft 14 b limits the transmission on the input side The second hollow wheel P 23 b is connected directly to the drive shaft 14 b . For connecting the fourth planetary wheel carrier P 42 b , the drive shaft 14 b is guided axially and radially between the fourth planetary gear unit P 4 b and the power output shaft 15 b . The connection shaft 16 b is guided radially to the outside on the axial input side from the first planetary gear unit P 1 b . The connection shaft 17 b surrounds the second planetary gear unit P 2 b . It is guided radially and axially to the inside between the clutch unit S 4 b and the third planetary gear unit P 3 b and connected to the third sun wheel P 31 b and the fourth sun wheel P 41 b . The connection shaft 18 a is guided radially and axially to the outside between the drive shaft 14 b and the connection shaft 16 b . It further passes through the first sun wheel P 11 b and is guided to the outside radially and axially between the planetary gear units P 1 b , P 2 b for connecting the second planetary wheel carrier P 22 b . For the connection of the clutch element S 42 b , it passes through the second planetary gear unit P 2 b and is guided radially and axially to the outside between the second planetary gear unit P 2 b and the connection shafts 17 b . The connection shaft 19 b is guided radially and axially to the outside between the first planetary gear unit P 1 b and the second planetary gear unit P 2 b for connecting the planetary wheel carrier P 12 b and the hollow wheel P 23 b . The power output shaft 15 b is guided axially and radially to the outside between the third planetary gear unit P 3 b and the fourth planetary gear unit P 4 b . It surrounds the fourth planetary gear unit P 4 b and limits the transmission unit on the output side.

The forward transmission gears V 1 b -V 9 b are shifted by means of the clutch units S 1 b , S 2 b , S 3 b , S 4 b , S 5 b , S 6 b (see FIG. 6 ). The transmissions of the two embodiments are kinematically equivalent. The clutch unit S 3 b has a changed clutch compared to the previous embodiment, this is why the transmission gears V 1 b -V 9 b have changed power flows particularly with regard to a strain on the connection shafts 16 b , 17 b , 18 b , 19 b . A shift logic of the transmission unit is unchanged. Due to the changed standing transmission ratio of the planetary gear units P 2 b , P 3 b , P 4 b , the transmission gears V 1 b -V 9 b have different transmission ratios 1 1 b- 1 9 b. For shifting the forward transmission gears V 2 b , V 3 b , V 5 b , V 6 b , the second sun wheel P 21 b and the second planetary wheel carrier P 22 a can be connected in a rotationally fixed manner by means of the clutch unit S 3 b , whereby the second planetary gear unit P 2 b can be blocked by means of the clutch unit S 3 b.

The first forward transmission gear V 1 b has a transmission ratio i 1 b of 5.5536 between the drive unit 11 b and the power output unit 12 b in this embodiment. The first forward transmission gear V 1 b is formed by closing the clutch units S 2 b , S 4 b , S 5 b . The clutch unit S 2 b connects the first sun wheel P 11 b to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 4 b connects the second planetary wheel carrier P 22 b to the first hollow wheel P 13 b and the third sun wheel P 31 b in a rotationally fixed manner. The clutch unit S 5 b connects the third hollow wheel P 33 b to the transmission housing 13 b in a rotationally fixed manner. A power flow for the first unit gear V 1 b is introduced via the second planetary gear unit P 2 b and is split via the clutch unit S 4 b . A part of the power flow is fed back to the second planetary gear unit P 2 b via the first planetary gear unit P 1 b . A further part of the power flow is diverted via the third planetary gear unit P 3 b.

The second forward transmission gear V 2 b has a transmission ratio i 2 b of 3.556 between the drive unit 11 b and the power output unit 12 b in this embodiment. The second forward transmission gear V 2 b is formed by closing the clutch units S 3 b , S 4 b , S 5 b . The clutch unit S 3 b connects the second planetary wheel carrier P 22 b to the second sun wheel P 21 b in a rotationally fixed manner. The clutch unit S 4 b connects the second planetary wheel carrier P 22 b to the third sun wheel P 31 b in a rotationally fixed manner. The clutch unit S 6 b connects the third hollow wheel P 33 b to the transmission housing 13 b in a rotationally fixed manner. A power flow for the second forward transmission gear V 2 b is introduced via the second planetary gear unit P 2 b and is diverted via the third planetary gear unit P 3 b.

The third forward transmission gear V 3 b has a transmission ratio i 3 b of 2.359 between the drive unit 11 b and the power output unit 12 b in this embodiment. The third forward transmission gear V 3 b is formed by closing the clutch units S 2 b , S 3 b , S 5 b . The clutch unit S 2 b connects the first sun wheel P 11 b to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 3 b connects the second planetary wheel carrier P 22 b to the second sun wheel P 21 b in a rotationally fixed manner. The clutch unit S 5 b connects the third hollow wheel P 33 b to the transmission housing 13 b in a rotationally fixed manner. A power flow for the third forward transmission gear V 3 b is introduced via the second planetary gear unit P 2 b , guided further via the first planetary gear unit P 1 b and is again diverted via the third planetary gear unit P 3 b.

The fourth forward transmission gear V 4 b has a transmission ratio i 4 b of 1.701 between the drive unit 11 b and the power output unit 12 b in this embodiment. The fourth forward transmission gear V 4 b is formed by closing the clutch units S 2 b , S 5 b , S 6 b . The clutch unit S 2 b connects the first sun wheel P 11 b to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 5 b connects the third hollow wheel P 33 b to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 6 b connects the fourth hollow wheel P 43 b to the power output unit 12 b in a rotationally fixed manner. A power flow for the fourth forward transmission gear V 4 b is introduced via the fourth planetary gear unit P 4 b and is split via the clutch unit S 6 b . A part of the power flow is fed back to the fourth planetary gear unit P 4 b via the third planetary gear unit P 3 b . A further part of the power flow is diverted directly.

The fifth forward transmission gear V 5 b has a transmission ratio i 5 b of 1.238 between the drive unit 11 b and the power output unit 12 b in this embodiment. The fifth forward transmission gear V 5 b is formed by closing the clutch units S 2 b , S 3 b , S 6 b . The clutch unit S 2 b connects the first sun wheel P 11 b to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 3 b connects the second planetary wheel carrier P 22 b to the second sun wheel P 21 b in a rotationally fixed manner. The clutch unit S 6 b connects the fourth hollow wheel P 43 b to the power output unit 12 b in a rotationally fixed manner. A power flow for the fifth forward transmission gear V 6 b is split by means of the drive shaft 11 b . A part of the power flow is diverted directly via the fourth planetary gear unit P 4 b , a further part is fed back to the drive unit 11 b via the blocked second planetary gear unit P 2 b . A part of the power flow guided via the fourth planetary gear unit P 4 b is also guided to the second planetary gear unit P 2 b via the first planetary gear unit P 1 b .

The sixth forward transmission gear V 6 b has a transmission ratio i s b of 1.000 between the drive unit 11 b and the power output unit 12 b in this embodiment. It is formed as a direct gear. The sixth forward transmission gear V 6 b is formed by closing the clutch units S 3 b , S 4 b , S 6 b . The clutch unit S 3 b connects the second planetary wheel carrier P 22 b to the fourth sun wheel P 41 b in a rotationally fixed manner. The clutch unit S 4 b connects the second planetary wheel carrier P 22 b to the fourth sun wheel P 41 b in a rotationally fixed manner. The clutch unit S 6 b connects the fourth hollow wheel P 43 b to the power output unit 12 b in a rotationally fixed manner. A power flow for the sixth forward transmission gear V 6 b is introduced via the fourth planetary gear unit P 4 b and is split. A part of the power flow is fed back to the drive unit 11 b via the second planetary gear unit P 2 b . A further part of the power flow is diverted again via the fourth planetary gear unit P 4 b.

The seventh forward transmission gear V 7 b has a transmission ratio i 7 b of 0.881 between the drive unit 11 b and the power output unit 12 b in this embodiment. The seventh forward transmission gear V 7 b is formed by closing the clutch units S 2 b , S 4 b , S 6 b . The clutch unit S 2 b connects the first sun wheel P 11 b to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 4 b connects the second planetary wheel carrier P 22 b to the fourth sun wheel P 41 b in a rotationally fixed manner. The clutch unit S 6 b connects the fourth hollow wheel P 43 b to the power output unit 12 b in a rotationally fixed manner. A power flow for the seventh forward transmission gear V 7 b is introduced via the fourth planetary gear unit P 4 b and is split. A part of the power flow is fed back to the drive unit 11 b via the second planetary gear unit P 2 b and the first planetary gear unit P 1 b . A further part of the power flow is diverted via the fourth planetary gear unit P 4 b.

The eighth forward transmission gear V 8 b has a transmission ratio i 8 b of 0.726 between the drive unit 11 b and the power output unit 12 b in this embodiment. The eighth forward transmission gear V 8 b is formed by closing the clutch units S 1 b , S 4 b , S 6 b . The clutch unit S 1 b connects the second planetary wheel carrier P 22 b to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 4 b connects the fourth sun wheel P 41 b to the second planetary wheel carrier P 22 b and thus to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 6 b connects the fourth hollow wheel P 43 b to the drive unit in a rotationally fixed manner. A power flow for the eighth forward transmission gear V 8 b is introduced and diverted via the fourth planetary gear unit P 4 b.

The ninth forward transmission gear V 9 b has a transmission ratio i 9 b of 0.580 between the drive unit 11 b and the power output unit 12 b in this embodiment. The ninth forward transmission gear V 9 b is formed by closing the clutch units S 1 b , S 2 b , S 5 b . The clutch unit S 1 b connects the second planetary wheel carrier P 22 b to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 2 b connects the fourth hollow wheel P 43 b to the drive unit 12 b in a rotationally fixed manner. A power flow for the ninth forward transmission gear V 9 b introduced via the drive unit 11 b is split in front of the first planetary gear unit P 1 b . A first part of the power flow is guided to the fourth planetary gear unit P 4 b via the second planetary gear unit P 2 b and the first planetary gear unit P 1 b . A second part of the power flow is directly guided to the fourth planetary gear unit P 4 b . The power flow is combined again and diverted by means of the fourth planetary gear unit P 4 b.

The reverse transmission gear R 1 b has a transmission ratio i R b of −3.901 between the drive unit 11 b and the power output unit in this embodiment. The reverse transmission gear R 1 b is formed by closing the clutch units S 1 b , S 2 b , S 5 b . The clutch unit S 1 b connects the second planetary wheel carrier P 22 b to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 2 b connects the first sun wheel P 11 b to the transmission housing 13 b in a rotationally fixed manner. The clutch unit S 5 b connects the third hollow wheel P 33 b to the transmission housing 13 b in a rotationally fixed manner. A power flow for the reverse transmission gear R 1 b is introduced via the second planetary gear unit P 2 b , guided to the third planetary gear unit P 3 b via the first planetary gear unit P 1 b and is diverted again via the third planetary gear unit P 3 .

A progressive ratio φ 1/2 b between the first and the second forward transmission gear V 1 b V 1 b , V 2 b is 1.557. A progressive ratio φ 2/3 b between the second and the third forward transmission gear V 2 b , V 3 b is 1.508. A progressive ratio φ 3/4 b between the third and the fourth forward transmission gear V 3 b , V 4 b is 1.386. A progressive ratio φ 4/5 b between the fourth and the fifth forward transmission gear V 4 b , V 5 b is 1.375. A progressive ratio φ 5/6 b between the fifth and the sixth forward transmission gear V 5 b , V 6 b is 1.238. A progressive ratio φ 6/7 b between the sixth and the seventh forward transmission gear V 6 b , V 7 b is 1.135. A progressive ratio φ 7/8 b between the seventh and the eighth forward transmission gear V 7 b , V 8 b is 1.214. A progressive φ 8/9 b ratio between the eighth and the ninth forward transmission gear V 8 b , V 9 b is 1.250. A total spread of the transmission unit between the first forward transmission gear V 1 b and the ninth forward transmission gear V 9 b is about 9.5. A spread between the first forward transmission gear V 1 b and the eighth forward transmission gear V 8 b is about 7.6. A spread between the second forward transmission gear V 2 b and the ninth forward transmission gear V 9 b is about 6.1. The transmission unit can basically also be used as an eight gear transmission.