Power split transmission and methods for operating a power split transmission and drive train

Abstract

Power split transmission (28) with a first power path and a second power path, wherein the first power path is a mechanical power path and the power split transmission an input wave (12), an output wave (16), a primary planetary gear set (P1) comprising a first primary sun gear (P111), a second primary sun gear (P112), a common primary planet carrier (P12) and at least one common primary planet gear (P13), a secondary planetary gear set (P2) with a secondary sun gear (P21), a secondary planet carrier (P22) and at least one secondary ring gear (P24), a tertiary planetary gear set (P3) with a first tertiary planetary gear set element (P32), a first switching element (S1), a second switching element (S2), a third switching element (S3), and a fourth switching element (S4) includes, wherein the first primary sun gear (P111) is rotationally fixed to the input shaft (12), wherein the common primary planet carrier (P12) and the secondary sun gear (P21) can be optionally coupled in a rotationally fixed manner via the first switching element (S1), wherein the second primary sun gear (P112) and the secondary sun gear (P21) can be optionally coupled in a rotationally fixed manner via the second switching element (S2), wherein the common primary planet carrier (P12) and the secondary ring gear (P24) can be optionally coupled in a rotationally fixed manner via the third switching element (S3), wherein the secondary ring gear (P24) can be optionally coupled to a gearbox housing (44) via the fourth switching element (S4) in a rotationally fixed manner, wherein the secondary planet carrier (P22) is rotationally fixedly coupled to the first tertiary planet gear set element (P32), and wherein the output shaft (16) is rotationally fixedly coupled to the first tertiary planetary gear set element (P32).

Description

[0001] The invention relates to a power split transmission having a first power path and a second power path, wherein the first power path is a mechanical power path, and to a method for operating such a power split transmission.

[0002] Furthermore, the invention relates to a drive train of a work machine, in particular a mobile work machine, with a power split transmission.

[0003] Power-split transmissions are frequently used in the drivetrains of off-highway machinery and are generally well-known in the art. Examples of off-highway machinery include agricultural machinery such as tractors or construction machinery such as wheel loaders.

[0004] DE 10 2017 219 999 A1 describes a continuously variable power-split transmission with at least four driving ranges, in which the gear ratio is continuously variable within the range of a variator. A first planetary gear set, comprising several shafts, can be operatively connected via various shifting elements to another planetary gear set, also comprising several shafts. This is connected to the transmission output shaft or can be connected to it. The first planetary gear set comprises four shafts and is coupled to a transmission input shaft and the variator shafts, with the individual shafts being connected to each other via various shifting elements.

[0005] DE 601 03 717 T2 discloses a system in which the output speed of a hydrostatic unit is determined using a pair of sensors in different transmission gears. One sensor measures the speed directly at the output of the hydrostatic unit, while the other sensor detects it indirectly at the planetary carrier. The speed of the hydrostatic unit must be calculated based on the engine speed and the known transmission gear ratios. DE 197 57 329 A1 describes an adjustable hydrostatic unit combined with a multi-shaft planetary gear set. The transmission has two input shafts and at least two output shafts connected to multi-stage gear sets to form gear groups. These gear sets are coupled to each other at synchronization points by engaging and disengaging clutches to perform gear changes.

[0006] DE 37 09 191 A1 discloses a continuously variable transmission for motor vehicles that includes at least three forward drive ranges. It consists of a converter consisting of a primary and a secondary unit, as well as a four-shaft summing planetary gear. This summates the input power divided into two power branches and transmits it to a downstream second planetary gear unit. This planetary gear unit is responsible for switching between forward and reverse drive ranges.

[0007] DE 39 09 940 A1 describes a powershift transmission with continuously variable transmission ratios, comprising a power-split coupling mechanism. This is driven by a main drive shaft and connected to a servo-gearbox and a manual transmission. The coupling mechanism has two coupling shafts whose speeds are equal at the adjustment range limit of the servo-gearbox. When the servo-gearbox is adjusted, the speed of the coupling shafts changes continuously, and they can be alternately connected to the manual transmission. One of the coupling shafts is coupled to an input shaft of a superposition transmission to enable a variable ratio to the main drive shaft.

[0008] Conventional power-split transmissions typically provide several operating ranges comprising different gear ratios. These operating ranges can generally be changed without interrupting traction. Particularly in applications where the power-split transmission is used in a traction drive train, both forward and reverse operating ranges must be available, also referred to as forward and reverse ranges. In conventional applications, this is ensured by so-called switching units or reversing units, which are connected downstream of a main transmission designed as a power-split transmission. Another alternative term for switching unit is reversing unit.

[0009] Starting from a power-split main gearbox, the switching or reversing units are arranged along a gearbox axis of the main gearbox adjacent to it, so that the axial installation space requirement of this gearbox group increases starting from the main gearbox.

[0010] In general, however, the aim in transmission technology is to make transmissions as compact as possible, especially with regard to their axial length. This is especially important for electromechanical power-split transmissions, where space must be provided for the electrical motors. The object of the invention is therefore to create a power-split transmission with a particularly short axial length. Consequently, the overall space requirement of a drive train incorporating such a power-split transmission is reduced. It is understood that axial compactness must not be achieved at the expense of the other transmission functionalities. One of the most important transmission functionalities is the provision of operating ranges, which are also referred to as driving ranges in moving machines.

[0011] The task is solved by a power split transmission of the type mentioned above, comprising an input shaft, an output shaft, a primary planetary gear set having a first primary sun gear, a second primary sun gear, a common primary planet carrier and at least one common primary planet gear, a secondary planetary gear set with a secondary sun gear, a secondary planet carrier and at least one secondary ring gear, a tertiary planetary gear set with a first tertiary planetary gear set element, a first switching element, a second switching element, a third switching element, and a fourth switching element, wherein the first primary sun gear is rotationally fixedly coupled to the input shaft, wherein the common primary planet carrier and the secondary sun gear can be selectively coupled in a rotationally fixed manner via the first switching element, wherein the second primary sun gear and the secondary sun gear can be selectively coupled in a rotationally fixed manner via the second switching element, wherein the primary planet carrier and the secondary ring gear can be selectively coupled in a rotationally fixed manner via the third switching element, wherein the secondary ring gear can be selectively coupled to a transmission housing via the fourth switching element in a rotationally fixed manner, wherein the secondary planet carrier is rotationally fixedly coupled to the first tertiary planetary gear set element, and The output shaft is non-rotatably coupled to the first tertiary planetary gear set element. In this context, a shifting element is a collective term for brakes and clutches, with brakes always acting relative to the transmission housing and clutches always coupling two rotatable components. In this case, the first shifting element, the second shifting element, and the third shifting element are designed as clutches, and the fourth shifting element as a brake. Such a power-split transmission is comparatively compact axially because it uses planetary gear sets. These are particularly well suited to implementing transmissions that can transmit high torques but still require little space, particularly axially.

[0012] The design of the primary planetary carrier as a common planetary carrier and the primary planetary gear as a common planetary gear results in the power-split transmission having comparatively few components. This makes it simple in construction and lightweight. This design also saves space. Costs can also be reduced due to the smaller number of components.

[0013] The power split transmission is preferably a continuously variable transmission. The individual operating ranges or driving ranges of the power split transmission can therefore be changed without step changes in gear ratio. In other words, the gear ratio provided by the power split transmission can be continuously adjusted across the various operating or driving ranges.

[0014] The shifting elements installed in the power-split transmission can operate with frictional or positive engagement. Shifting elements designed as clutches can be claw clutches or multi-disk clutches. Shifting elements designed as brakes can be multi-disk brakes or claw couplings.

[0015] In a preferred embodiment, the shared primary planetary gear is a multi-stage planetary gear. It thus fulfills the function of two planetary gears, with these two planetary gears having different diameters. There is therefore no geometric dependency between the two planetary gears formed by the shared planetary gear. This allows the primary planetary gear set to be freely designed with regard to its gear ratios and size.

[0016] Since the primary planetary gear set comprises a common planet carrier and a common primary planetary gear, it can be equipped with only a single ring gear. This means the associated power-split transmission has comparatively few components. It thus has a relatively simple design, is lightweight, and requires only a small amount of space.

[0017] The aforementioned power-split transmission has a transmission axis that corresponds to the centerline of the planetary gear sets. Thus, during traction operation, the power flow occurs along this transmission axis. Furthermore, the input shaft and output shaft are preferably located on the transmission axis.

[0018] According to one embodiment, a fifth shifting element and / or a sixth shifting element are / is present. The fourth and fifth shifting elements form a shifting unit integrated into the power-split transmission. This offers a forward gear or forward driving range and a reverse gear or reverse driving range. A shifting unit designed as a secondary transmission is thus dispensed with, resulting in a smaller axial installation space requirement. Furthermore, four forward driving ranges and two reverse driving ranges can be realized via the total of six shifting elements, as will be explained later. Given this range of functions, the power-split transmission has comparatively few components and is compact in design.

[0019] The tertiary planetary gear set can be a negative planetary gear set, with the first tertiary planetary gear element being a tertiary planet carrier, and the second tertiary planetary gear element being a tertiary ring gear. A planetary gear set is a negative planetary gear set if the two coaxial central gears, i.e., the ring gear and the sun gear, rotate in opposite directions when the planet carrier is stationary. This means that the stationary ratio of the corresponding transmission is negative.

[0020] In this context, the second tertiary planetary gear set element, designed as a tertiary ring gear, can be selectively coupled in a rotationally fixed manner to the transmission housing via the fifth shifting element, and the secondary ring gear can be rotationally fixedly coupled to a tertiary sun gear. Alternatively, a tertiary ring gear can be rotationally fixedly coupled to the transmission housing, and the secondary ring gear can be selectively coupled in a rotationally fixed manner to a tertiary sun gear via the fifth shifting element. Such couplings are advantageous from the perspective of the torque flow from the input shaft to the output shaft of the power-split transmission. In particular, the torque is transmitted to the output shaft comparatively directly, i.e., in particular without any backflow. Such a design of the power-split transmission results in a compact design.

[0021] Alternatively, the tertiary planetary gear set can be a positive planetary gear set, with the first tertiary planetary gear element being a tertiary ring gear and the second tertiary planetary gear element being a tertiary planet carrier. A planetary gear set is a positive planetary gear set if the two coaxial central gears, i.e., the ring gear and the sun gear, rotate in the same direction when the planet carrier is stationary. The stationary ratio of a corresponding transmission is then positive. A positive planetary gear set always has two planetary groups, i.e., at least one inner planetary gear and one outer planetary gear, which are coupled to a common planet carrier.

[0022] In one variant, the second tertiary planetary gear set element is a tertiary planet carrier, which can be selectively coupled to the transmission housing via the fifth shift element in a rotationally fixed manner, and the secondary ring gear is coupled to a tertiary sun gear. Such couplings are advantageous from the perspective of the torque flow from the input shaft to the output shaft of the power-split transmission. In particular, the torque is transmitted to the output shaft relatively directly, i.e., without any reverse flow. This design of the power-split transmission results in a compact design.

[0023] In a design alternative, it may be provided that the secondary sun gear can be coupled to the secondary planet carrier via the sixth switching element in a rotationally fixed manner or that the secondary sun gear can be coupled to the secondary ring gear via the sixth switching element in a rotationally fixed manner or that the secondary planetary carrier can be optionally coupled to the secondary ring gear via the sixth shift element in a rotationally fixed manner. This allows the secondary planetary gear set to be locked together. This results in an additional forward gear or forward driving range, since the secondary planetary gear set has no transmission function when locked together. A driving range implemented in this way is very efficient in terms of the associated installation space requirements.

[0024] Preferably, the first shifting element and the second shifting element are arranged radially nested, in particular with the second shifting element located radially within the first shifting element. The shifting element can thus be designed as a so-called double shifting element. This allows for reduced installation space, particularly axial space, to be achieved. If the first shifting element and the second shifting element are designed as multi-disk clutches, they can use a common disk carrier in this arrangement, which simplifies the design of the transmission and further reduces space requirements.

[0025] The third switching element and the sixth switching element can also be arranged radially nested, in particular with the sixth switching element located radially within the third switching element. This results in the effects and advantages explained with regard to the first and second switching elements.

[0026] Furthermore, it is possible for the fourth shifting element and the fifth shifting element to be arranged radially nested, in particular with the fifth shifting element located radially within the fourth shifting element. In this case, the tertiary planetary gear set is designed as a negative planetary gear set. This again results in the effects and advantages explained with regard to the first and second shifting elements.

[0027] According to one variant, the fourth shifting element and / or the fifth shifting element are located radially outside the secondary planetary gear set and / or the tertiary planetary gear set. In other words, the shifting elements and the planetary gear sets are radially nested. This also efficiently utilizes the existing tree. Furthermore, the shifting elements are easily accessible, for example, for maintenance work.

[0028] A first adjustment unit of the second power path can be rotationally coupled to the input shaft, in particular via a gear ratio stage, and a second adjustment unit of the second power path, which is coupled to the first adjustment unit via the second power path, can be rotationally coupled to a primary ring gear, in particular via a gear ratio stage. These gear ratio stages can be designed as spur gear stages or planetary gear stages. This allows the power split transmission to be easily integrated into an associated drive train, allowing, in particular, the desired gear ratios and directions of rotation to be set.

[0029] Preferably, the second power path is an electrical power path, and the first adjustment unit comprises a first electrical machine and the second adjustment unit comprises a second electrical machine, or the second power path is a hydraulic power path, and the first adjustment unit comprises a first hydrostatic drive and the second adjustment unit comprises a second hydrostatic drive. The power generation transmission is then either an electromechanical power split transmission or a hydraulic-mechanical power split transmission. Both transmission types have proven themselves in the field of work machines. In particular, these transmission types are well suited to the environmental conditions prevailing in the field of work machines, which leads to a high level of reliability for such power split transmissions.

[0030] In addition, the object is achieved by a method for operating a power split transmission according to the invention, in which a first forward driving range is set by closing the first switching element and the fourth switching element and opening all other switching elements, a second forward driving range is set by closing the second switching element and the fourth switching element and opening all other switching elements, a third forward driving range is set by closing the third switching element and the second switching element and opening all other switching elements, a fourth forward driving range is set by closing the second switching element and a sixth switching element and opening all other switching elements, a first reverse driving range is set by closing the first switching element and a fifth switching element and opening all other switching elements, and / or A second reverse range is set by closing the second shift element and the fifth shift element and opening all other shift elements. This allows for four forward ranges and two reverse ranges. Given this range of functions, the power-split transmission is compact, particularly in terms of its axial length.

[0031] The operating ranges of transmissions are always referred to as driving ranges in these documents. However, this is not intended to imply that only transmissions that are associated with a drive system are meant. Rather, it also explicitly refers to transmissions that are not. Therefore, all specified driving ranges are to be understood as operating ranges in the broadest sense.

[0032] The object is further achieved by a drive train of a work machine of the type mentioned above, which comprises a power-split transmission according to the invention, wherein the drive train is assigned in particular to a mobile work machine. Due to the previously explained compactness of the power-split transmission, a drive train is created in which there is sufficient space for electrical machines, which are present particularly in electromechanical power-split transmissions and must be integrated into the drive train.

[0033] The invention is explained below using various embodiments shown in the accompanying drawings. They show: - Fig. 1 a drive train according to the invention with a power split transmission according to the invention, which can be operated by means of a method according to the invention, - Fig. 2 the power split transmission Fig. 1 in a detailed view, - Fig. 3 an alternative embodiment of the power split transmission from Fig. 2, - Fig. 4 one opposite the Fig. 1 alternative drive train according to the invention with a power split transmission according to the invention according to Fig. 3, - Fig. 5 a further, compared to the embodiments of the Fig. 2 and Fig. 3 alternative embodiment of the power split transmission according to the invention, - Fig. 6 one of the power split transmissions from the Fig. Circuit diagram belonging to 1 to 5 - Fig. 7 a power split transmission according to the invention according to an additional embodiment, - Fig. 8 one opposite the Fig. 1 and Fig. 4 alternative drive train according to the invention with a power split transmission according to the invention according to a further variant, - Fig. 9 the power split transmission Fig. 8 in a detailed view.

[0034] Fig. 1 shows a drive train 10 for a mobile work machine.

[0035] On the one hand, this serves to drive a power take-off shaft, for which a PTO gearbox 14 is provided. On the other hand, the drive train 10 serves as the drive for the mobile work machine. An output shaft 16 is provided for this purpose.

[0036] A front wheel output 18 and a rear wheel output 20 can be supplied with power in the form of speed and torque via the output shaft 16.

[0037] Furthermore, the drive train 10 is used to drive other units and pumps that are installed in the Fig. 1 are shown only schematically and are provided with the reference number 22.

[0038] The power source of the drive train 10 is a drive motor 24, schematically depicted here as an internal combustion engine. This motor drives an input shaft 12 via a vibration damper 26.

[0039] In the illustrated embodiments, both the input shaft 12 and the output shaft 16 are arranged on a transmission axis 27.

[0040] A continuously variable, mechanical-electrical power split transmission 28 is connected between the input shaft 12 and the output shaft 16.

[0041] The mechanical train or mechanical power branch of this power split transmission 28 comprises a primary planetary gear set P1, a secondary planetary gear set P2 and a tertiary planetary gear set P3, which will be discussed in detail later.

[0042] The electrical train or electrical power branch of the power split transmission 28 includes a first adjustment unit 36 ​​and a second adjustment unit 38, which are each designed as electrical machines and are electrically coupled to one another.

[0043] The two adjustment units 36, 38 are also coupled to an electrical storage unit 42 via a control unit 40. This storage unit 42 can serve as the energy source for the drive train 10 in addition to the drive motor 24. Such drive trains can be referred to as hybrid.

[0044] In the Fig. In the embodiment shown in Figure 1, the first adjusting unit 36 ​​is non-rotatably coupled to the input shaft 12 via a gear stage not designated in more detail, which is shown as a spur gear stage.

[0045] The second adjusting unit 38 is non-rotatably coupled to the first planetary gear set P1 via a further, unspecified gear stage, which is shown as a spur gear stage.

[0046] The power split transmission 28 is in Fig. 2 shown in detail.

[0047] As already mentioned, it comprises a primary planetary gear set P1. This has a first primary sun gear P111, a second primary sun gear P112, a common primary planet carrier P12, and at least one common primary planet gear P13. The primary planetary gear set P1 also includes a primary ring gear P14.

[0048] The common primary planetary gear P13 is designed as a stepped planetary gear.

[0049] In addition, the primary ring gear P14 is the only ring gear of the primary planetary gear set P1.

[0050] The primary ring gear P14 is assigned, for example, to the second primary sun gear P112. In other words, the first primary sun gear P111 is designed to be ring gear-free, as no ring gear is (directly) assigned to the first primary sun gear P111, as can be seen from Fig. 2 becomes clear.

[0051] The secondary planetary gear set P2 of the power split transmission 28 has a secondary sun gear P21, a secondary planet carrier P22, a secondary planet gear P23 and at least one secondary ring gear P24.

[0052] Furthermore, the power split transmission 28 comprises the tertiary planetary gear set P3, which in the embodiment according to Fig. 1 and Fig. 2 is designed as a minus planetary gear set.

[0053] The tertiary planetary gear set P3 thus has a tertiary sun gear P31, a first tertiary planetary gear set element P32, which is designed as a tertiary planet carrier, a tertiary planetary gear P33 and a second tertiary planetary gear set element P34, which is designed as a tertiary ring gear.

[0054] These elements are coupled as follows.

[0055] The first adjustment unit 36 ​​is non-rotatably coupled to the input shaft 12.

[0056] The first primary sun gear P111 is also rotationally coupled to the input shaft 12.

[0057] The second adjustment unit 38 is rotationally fixedly coupled to the primary ring gear 14.

[0058] As regards the secondary planetary gear set P2 and the tertiary planetary gear set P3, the secondary planet carrier P22 is non-rotatably coupled to the first tertiary planetary gear set element P32, which in the variant shown is a tertiary planet carrier.

[0059] Furthermore, the output shaft 16 is rotationally fixedly coupled to the first tertiary planetary gear set element P32, i.e. to the tertiary planet carrier.

[0060] In addition, the secondary ring gear P24 is rotationally fixedly coupled to the tertiary sun gear P31.

[0061] In addition, six switching elements S1, S2, S3, S4, S5, S6 are provided.

[0062] The common primary planet carrier P12 and the secondary sun gear P21 can be optionally coupled in a rotationally fixed manner via a first switching element S1.

[0063] The second primary sun gear P112 and the secondary sun gear P21 can be optionally coupled in a rotationally fixed manner via a second switching element S2.

[0064] The common primary planet carrier P12 and the secondary ring gear P24 can be optionally coupled in a rotationally fixed manner via a third switching element S3.

[0065] The secondary ring gear P24 can be optionally coupled to a transmission housing 44 in a rotationally fixed manner via a fourth switching element S4.

[0066] The second tertiary planetary gear set element P34, which is designed as a tertiary ring gear, can also be optionally coupled in a rotationally fixed manner to the transmission housing 44 via a fifth switching element S5.

[0067] The secondary sun gear P21 can be optionally coupled to the secondary planet carrier P22 in a rotationally fixed manner via a sixth switching element S6.

[0068] The first switching element S1 and the second switching element S2 are in the variant according to Fig. 1 and Fig. 2 are arranged radially nested. The second switching element S2 is located radially within the first switching element S1.

[0069] If the first switching element S1 and the second switching element S2 are designed as multi-disk clutches, a common disc carrier can be used.

[0070] The third switching element S3 and the sixth switching element S6 are also arranged radially nested, with the sixth switching element S6 being located radially inside the third switching element S3. In the embodiment according to Fig. 1 and Fig. 2, however, the third switching element S3 and the sixth switching element S6 use separate plate carriers, provided that the switching elements S3, S6 are designed as multi-plate clutches.

[0071] The fourth shifting element S4 and the fifth shifting element S5 are arranged radially outside the secondary planetary gear set P2 and the tertiary planetary gear set P3.

[0072] In Fig. 3 shows an alternative embodiment of the power split transmission 28, which differs from the embodiment according to Fig. 2 only in that the sixth switching element S6 now optionally couples the secondary sun gear P21 with the secondary ring gear P24 in a rotationally fixed manner. For the rest, please refer to the explanations for Fig. 2.

[0073] Furthermore, the third shift element S3 and the sixth shift element S6, if they are designed as multi-plate clutches, can now use a common plate carrier.

[0074] After the sixth switching element S6 in the variant according to Fig. 3 only has to maintain a comparatively small locking torque when locking the secondary planetary gear set, it can be designed to be comparatively compact.

[0075] In the event that the sixth switching element S6 is a multi-plate clutch, it can have comparatively few plates.

[0076] Fig. 4 shows the power split transmission 28 in the overall context of the drive train 10. This corresponds, with the exception of the power split transmission, to the drive train of Fig. 1, so please refer to the relevant comments.

[0077] In Fig. 5 shows a further alternative embodiment of the power split transmission 28, which differs from the embodiments of the Fig. 2 and Fig. 3 in that the sixth switching element S6 optionally couples the secondary planet carrier P22 and the secondary ring gear P24 in a rotationally fixed manner. For the rest, please refer to the explanations for Fig. 2.

[0078] With regard to the arrangement of the third switching element S3 and the sixth switching element S6, the embodiment according to Fig. 5 of the embodiment from Fig. 3.

[0079] The Fig. The power split transmissions 28 shown in Figures 1 to 5 can be operated using the method explained below. A corresponding circuit diagram is shown in Fig. 6 shown.

[0080] In this context, a first forward driving range FB-V1 is set by closing the first switching element S1 and the fourth switching element S4 and opening all other switching elements.

[0081] A second forward driving range FB-V2 is selected by closing the second switching element S2 and the fourth switching element S4 and opening all other switching elements.

[0082] A third forward driving range FB-V3 is realized by closing the third switching element S3 and the second switching element S2 and opening all other switching elements.

[0083] A fourth forward driving range FB-V4 is set by closing the second switching element S2 and the sixth switching element S6 and opening all other switching elements.

[0084] A first reverse gear range FB-R1 is engaged by closing the first switching element S1 and the fifth switching element S5 and opening all other switching elements.

[0085] A second reverse driving range FB-R2 is selected by closing the second switching element S2 and the fifth switching element S5 and opening all other switching elements.

[0086] This results in four forward driving ranges and two reverse driving ranges.

[0087] Fig. 7 shows a further alternative of the power generation transmission 28. This differs only with regard to the tertiary planetary gear set P3 from the embodiment according to Fig. 2.

[0088] The tertiary planetary gear set P3 is now designed as a so-called plus planetary gear set.

[0089] This has an inner planetary gear P33i and an outer planetary gear P33a. It is known that positive planetary gear sets always have two planetary gear groups, whereas negative planetary gear sets require a single planetary gear group.

[0090] The first tertiary planetary gear set element 32 is now a tertiary ring gear.

[0091] It is non-rotatably coupled to the secondary planet carrier P22 and the output shaft 16.

[0092] The second tertiary planetary gear set element, P34, is now a tertiary planet carrier. This supports the two planetary gears P33a and P33i.

[0093] Furthermore, the planet carrier in the form of the second tertiary planetary gear set element P34 can be optionally coupled to the transmission housing 44 in a rotationally fixed manner via the fifth switching element S5.

[0094] For the rest, please refer to the comments on Fig. 2.

[0095] The power split transmission 28 according to Fig. 7 can be determined using the Fig. 6 explained procedure. The circuit diagram from Fig. 6 also applies to the power split transmission from Fig. 7.

[0096] In Fig. 8 shows an alternative drive train 10 which differs from the drive train 10 according to the Fig. 1 and Fig. 4 by a modified configuration of the power split transmission 28.

[0097] Now the fifth switching element S5 is designed as a clutch instead of as a brake as in the embodiments according to Fig. 1 and Fig. 4.

[0098] Furthermore, the first adjusting unit 36 ​​is now coupled to the input shaft 12 on a transmission output side instead of on a transmission input side as in the Fig. 1 and Fig. 4.

[0099] The power split transmission from Fig. 8 is in Fig. 9 shown in detail.

[0100] It differs only with regard to the tertiary planetary gear set P3 and its couplings from the power split transmission 28 Fig. 2.

[0101] The tertiary planetary gear set P3 is again designed as a minus planetary gear set.

[0102] The tertiary sun gear P31 can be optionally coupled to the secondary ring gear P24 in a rotationally fixed manner via the fifth switching element S5.

[0103] The first tertiary planetary gear set element P32 is again designed as a tertiary planet carrier and is connected in a rotationally fixed manner to the output shaft 16.

[0104] The second tertiary planetary gear set element P34 is designed as a ring gear and is non-rotatably coupled to the transmission housing 44.

[0105] The first switching element S1 and the second switching element S2 as well as the third switching element S3 and the sixth switching element S6 are as already with regard to the embodiment from Fig. 2 nested within each other.

[0106] In addition, the fourth switching element S4 and the fifth switching element S5 are now radially nested within each other, with the fifth switching element S5 lying radially within the fourth switching element S4.

[0107] In the event that the fourth switching element S4 and the fifth switching element S5 are designed as a multi-disk brake or a multi-disk clutch, they can use a common disc carrier.

[0108] The power split transmission 28 according to Fig. 8 and Fig. 9 can be operated using the previously explained method for operating the power generation transmission. The circuit diagram is shown in Fig. 6 also valid. Reference symbol 10 Drivetrain 12 Input shaft 14 PTO gearboxes 16 Output shaft 18 front wheel drive 20 rear wheel drive 22 units and pumps 24 drive motor 26 vibration dampers 27 Gear axle 28 power split transmissions 36 first adjustment unit 38 second adjustment unit 40 Control unit 42 storage unit 44 Gearbox housing P1 primary planetary gear set P111 first primary sun gear P112 second primary sun gear P12 common primary planet carrier P13 common primary planetary gear P14 primary ring gear P2 secondary planetary gear set P21 secondary sun gear P22 secondary planet carrier P23 secondary planetary gear P24 secondary ring gear P3 tertiary planetary gear set P31 tertiary sun gear P32 first tertiary planetary gear set element P33 tertiary planetary gear P34 second tertiary planetary gear set element S1 first switching element S2 second switching element S3 third switching element S4 fourth switching element S5 fifth switching element S6 sixth switching element

Claims

[1] Power split transmission (28) having a first power path and a second power path, wherein the first power path is a mechanical power path and the power split transmission an input shaft (12), an output shaft (16), a primary planetary gear set (P1) having a first primary sun gear (P111), a second primary sun gear (P112), a common primary planet carrier (P12) and at least one common primary planet gear (P13), a secondary planetary gear set (P2) with a secondary sun gear (P21), a secondary planet carrier (P22) and at least one secondary ring gear (P24), a tertiary planetary gear set (P3) with a first tertiary planetary gear set element (P32), a first switching element (S1), a second switching element (S2), a third switching element (S3), and a fourth switching element (S4), wherein the first primary sun gear (P111) is rotationally fixedly coupled to the input shaft (12), wherein the common primary planet carrier (P12) and the secondary sun gear (P21) can be selectively coupled in a rotationally fixed manner via the first switching element (S1), wherein the second primary sun gear (P112) and the secondary sun gear (P21) can be selectively coupled in a rotationally fixed manner via the second switching element (S2), wherein the common primary planet carrier (P12) and the secondary ring gear (P24) can be selectively coupled in a rotationally fixed manner via the third switching element (S3), wherein the secondary ring gear (P24) can be selectively coupled in a rotationally fixed manner to a transmission housing (44) via the fourth switching element (S4), wherein the secondary planet carrier (P22) is rotationally fixedly coupled to the first tertiary planetary gear set element (P32), and wherein the output shaft (16) is rotationally fixedly coupled to the first tertiary planetary gear set element (P32). [2] Power split transmission (28) according to claim 1, characterized by that a fifth switching element (S5) and / or a sixth switching element (S6) are present. [3] Power split transmission (28) according to claim 1 or 2, characterized by that the tertiary planetary gear set (P3) is a minus planetary gear set and the first tertiary planetary gear set element (P32) is a tertiary planet carrier and a second tertiary planetary gear set element (P34) is a tertiary ring gear. [4] Power split transmission (28) according to claims 2 and 3, characterized by , that the second tertiary planetary gear set element (P34), designed as a tertiary ring gear, can be selectively coupled in a rotationally fixed manner to the transmission housing (44) via the fifth shift element (S5), and the secondary ring gear (P24) is coupled in a rotationally fixed manner to a tertiary sun gear (P31), or a tertiary ring gear (P34) is rotationally fixedly coupled to the transmission housing (44) and the secondary ring gear (P24) can be selectively rotationally fixedly coupled to a tertiary sun gear (P31) via the fifth switching element (S5). [5] Power split transmission (28) according to claim 1 or 2, characterized by that the tertiary planetary gear set (P3) is a positive planetary gear set and the first tertiary planetary gear set element (P32) is a tertiary ring gear and the second tertiary planetary gear set element (P34) is a tertiary planet carrier. [6] Power split transmission (28) according to claims 2 and 5, characterized by that the second tertiary planetary gear set element (P34) is a tertiary planet carrier which can be selectively coupled in a rotationally fixed manner to the transmission housing (44) via the fifth shift element (S5) and the secondary ring gear (P24) is coupled in a rotationally fixed manner to a tertiary sun gear (P31). [7] Power split transmission (28) according to one of claims 2 to 6 as far as related to claim 2, characterized by , that the secondary sun gear (P21) can be coupled to the secondary planet carrier (P22) via the sixth switching element (S6) in a rotationally fixed manner or that the secondary sun gear (P21) can be coupled to the secondary ring gear (P24) via the sixth switching element (S6) in a rotationally fixed manner or that the secondary planet carrier (P22) can be optionally coupled in a rotationally fixed manner to the secondary ring gear (P24) via the sixth switching element (S6). [8] Power split transmission (28) according to one of the preceding claims, characterized by that the first switching element (S1) and the second switching element (S2) are arranged radially nested. [9] Power split transmission (28) according to one of claims 2 to 8 as far as related to claim 2, characterized bythat the third switching element (S3) and the sixth switching element (S6) are arranged radially nested. [10] Power split transmission (28) according to one of claims 2 to 9 as far as related to claim 2, characterized by that the fourth switching element (S4) and the fifth switching element (S5) are arranged radially nested. [11] Power split transmission (28) according to one of the preceding claims, characterized by that the fourth switching element (S4) and / or the fifth switching element (S5) are located radially outside the secondary planetary gear set (P2) and / or the tertiary planetary gear set (P3). [12] Power split transmission (28) according to one of the preceding claims, characterized byin that a first adjusting unit (36) of the second power path is rotationally coupled to the input shaft (12), in particular is rotationally fixedly coupled via a transmission stage, and a second adjusting unit (38) of the second power path, which is coupled to the first adjusting unit (36) via the second power path, is rotationally fixedly coupled to a primary ring gear (P14). [13] Power split transmission (28) according to one of the preceding claims, characterized by , that the second power path is an electrical power path and the first adjusting unit (36) comprises a first electrical machine and the second adjusting unit (38) comprises a second electrical machine or that the second power path is a hydraulic power path and the first adjusting unit (36) comprises a first hydrostat and the second adjusting unit (38) comprises a second hydrostat. [14] Method for operating a power split transmission (28) according to one of claims 1 to 13, characterized by , that a first forward driving range is set by closing the first switching element (S1) and the fourth switching element (S4) and opening all other switching elements, a second forward driving range is set by closing the second switching element (S2) and the fourth switching element (S4) and opening all other switching elements, a third forward driving range is set by closing the third switching element (S3) and the second switching element (S2) and opening all other switching elements, a fourth forward driving range is set by closing the second switching element (S2) and a sixth switching element (S6) and opening all other switching elements, a first reverse driving range is set by closing the first switching element (S1) and a fifth switching element (S5) and opening all other switching elements, and / or a second reverse driving range is set by closing the second switching element (S2) and the fifth switching element (S5) and opening all other switching elements. [15] Drive train (10) of a working machine with a power split transmission according to one of claims 1 to 13.

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