Planetary bottom bracket gearbox for a bicycle or e-bike

Abstract

The invention relates to a planetary bottom bracket gearbox for a bicycle or pedelec (1), with a crankshaft (WAn) as the drive and a gearbox output shaft (WAb) as the driven shaft, as well as further shafts (W1, W2, W3, W4, W5, W6), with three planetary gear sets (RS1, RS2, RS3), and with six shifting elements (B1, B2, B3, B3I, B3II, K1, K2, K3, K3I, K3II) for realizing several gears (G1, G2, G3, G4, G5, G6, G7, G8), wherein a first gearbox shifting group (3) and a second gearbox shifting group (4) are provided, wherein the first gearbox shifting group comprises a first planetary gear set (RS1) and a second planetary gear set (RS2) as well as a first shifting element (B1), a second shifting element (B2), a fourth shifting element (K1) and a fifth shifting element (K2), and wherein the second Gear shift group (4) is assigned a third planetary gear set (RS3) as well as a third shift element (B3, B3I, B3II) and a sixth shift element (K3, K3I, K3II).Furthermore, the invention relates to a bicycle or pedelec (1) with a bottom bracket gearbox.

Description

The present invention relates to a bottom bracket transmission of planetary design for a bicycle or a pedelec with a bottom crank shaft as drive and a transmission output shaft as output as well as further shafts, with three planetary gear sets and with six shift elements for realizing multiple gears. The invention further relates to a bicycle or pedelec with the bottom bracket transmission.For example, from the publication DE 10 2022 207 262 B3 a bottom bracket transmission of planetary construction for a bicycle or a pedelec is known. The bottom bracket transmission has a crank shaft as the drive and a transmission output shaft as the output and at least five further shafts, wherein the output is preferably effected via a sprocket, a belt wheel or the like. Furthermore, the bottom bracket transmission comprises three planetary gear sets which are arranged coaxially with the crank shaft, and six shift elements for realizing at least eight gears in the bottom bracket transmission. In addition, a first partial transmission with a first planetary gear set is provided, wherein a first shift element and a fourth shift element are assigned to the first partial transmission. Furthermore, a second subtransmission with a second planetary gear set and a third planetary gear set is provided as a positive planetary gear set, wherein a second shift element, a third shift element, a fifth shift element and a sixth shift element are assigned to the second subtransmission. To block the first planetary gear set, two elements of the first planetary gear set can be connected to one another via the fourth shift element.DE 10 2021 204 634 B3 relates to a bicycle transmission having at least three planetary gear sets and a plurality of shift elements. At least four gears can be realized by means of the bicycle transmission.DE 10 2018 208 387 A1 relates to a multi-stage transmission of planetary design for a bicycle or pedelec with a transmission input shaft as drive and a transmission output shaft as output, which comprises at least four planetary gear sets. At least four one-way clutches and four brakes are provided to implement sixteen speeds.DE 10 2022 206 684 B3 relates to a bottom bracket transmission of planetary design for a bicycle or pedelec having a pedal crankshaft as drive and a transmission output shaft as output, and at least four further shafts and three planetary gear sets. Five shift elements are provided to implement at least six gears.DE 10 2018 208 380 A1 relates to a multi-stage transmission of planetary design for a bicycle or pedelec with a transmission input shaft as drive and a transmission output shaft as output, which comprises at least three planetary gear sets. At least three one-way clutches and three brakes are provided to implement at least eight speeds.DE 10 2022 203 241 B3 relates to a bottom bracket transmission of planetary design for a bicycle or pedelec with a crank shaft as drive and a transmission output shaft as output, as well as at least four further shafts and three planetary gear sets. At least five shift elements are provided in order to realize at least six gears.DE 10 2021 209 258 A1 relates to a transmission for a bicycle having a planetary assembly, two brakes and two shift elements. The planetary assembly comprises two minus planetary gear sets, wherein the second sun gear is connected to an output and the second planetary carrier is connected to an input.DE 10 2022 209 139 B3 (post-published) relates to a bottom bracket transmission of planetary design for a bicycle or pedelec with a pedal crankshaft as drive and a transmission output shaft as output, and at least four further shafts and three planetary gear sets. Five shift elements are provided in order to realize at least five gears.The object of the present invention is to propose a bottom bracket transmission and a bicycle or pedelec with the bottom bracket transmission, which have the smallest possible construction outlay with properties improved compared to the prior art.This object is achieved according to the invention by the subject matter having the features of patent claim 1 or 2 or 13. Advantageous and claimed developments are evident from the dependent claims and the description and the drawings.Thus, a bottom bracket transmission of planetary construction for a bicycle or a pedelec is proposed. The bottom bracket transmission has a crank shaft as the drive and a transmission output shaft as the output and further shafts, wherein the output is preferably effected via a sprocket, a belt wheel or the like. Furthermore, the bottom bracket transmission comprises three planetary gear sets, and six shift elements for realizing, for example, eight gears in the proposed bottom bracket transmission. In order to realize a particularly effective and space-saving embodiment in the bottom bracket transmission, a first transmission shift group and a second transmission shift group are provided, wherein a first planetary gear set and a second planetary gear set as well as a first shift element, a second shift element, a fourth shift element and a fifth shift element are assigned to the first transmission shift group, wherein a third planetary gear set as well as a third shift element and a sixth shift element are assigned to the second transmission shift group, wherein the crank shaft Wan is connected to a second element of the second planetary gear set or to a third element of the third planetary gear set, wherein the transmission output shaft is connected or connectable to a second element of the third planetary gear set or is connected to a first element of the second planetary gear set, wherein a third element of the second planetary gear set is connected to a second element of the first planetary gear set, wherein a first element of the first planetary gear set is fixable to a housing or to any stationary component via a first shift element and is connectable to at least the second element of the second planetary gear set via a fourth shift element, wherein a third element of the first planetary gear set is fixable to the housing via a second shift element and is connectable to at least the first element of the second planetary gear set via a fifth shift element, wherein two elements of the third planetary gear set are fixedly connected and an element of the third planetary gear set is detachably connected, and wherein, in a first arrangement variant of the third shift element, a first element of the third planetary gear set is detachably connected to the housing via the third shift element, or wherein, in a second arrangement variant of the third shift element, the second element of the third planetary gear set is detachably connected to the transmission output shaft via the fifth shift element, or wherein, in a third arrangement variant of the fifth shift element, the third element of the third planetary gear set is detachably connected to the first element of the second planetary gear set via the fifth shift element.The proposed bottom bracket transmission thus essentially consists of two transmission shift groups or group transmissions, wherein the first transmission shift group is, for example, a 4-gear group, while the second transmission shift group is, for example, a 2-gear group, so that altogether, for example, eight gears can be realized. In this way, with the above-described connection of the only three planetary gear sets provided and the only six shift elements provided, a particularly simple and compact construction is realized in the proposed bottom bracket transmission. In addition, there are particularly low component loads and an advantageously high toothing efficiency due to the geometric transmission range in the bottom bracket transmission.The axial sequence of the two transmission shift groups coupled to one another can be interchanged in the case of the proposed bottom bracket transmission. Consequently, the first transmission shift group is connected upstream or downstream of the second transmission shift group between the transmission input shaft or the crankshaft and the transmission output shaft of the bottom bracket transmission.For the mechanical connection of elements, for example rotating elements or the like of the planetary gear sets, preferably, in addition to the drive and output, further shafts or shaft-like elements are used, wherein the term shaft is not to be understood exclusively as a cylindrical, rotatably mounted machine element for transmitting torques, but rather also to be understood as general connecting elements which connect the individual gear set elements to one another for transmitting torque.In the second transmission shift group of the proposed bottom bracket transmission, different blocking variants of the third planetary gear set are possible via a sixth shift element, which is designed as a clutch, in three different arrangement variants of the fifth shift element.Furthermore, in the second transmission shift group of the proposed bottom bracket transmission, different coupling variants of the three elements of the third planetary gear set are possible, of which a shiftable coupling is realized via the third shift element designed as a freewheel brake or freewheel, while the two remaining couplings are designed as fixed connections.In a first coupling variant described below, the three blocking variants described above are also possible.Accordingly, in the context of the first coupling variant of the third planetary gear set, it is provided in a first blocking variant of the third planetary gear set in the bottom bracket transmission that the crank shaft is connected to the second element of the second planetary gear set, that the transmission output shaft is connected directly or additionally via a sixth shaft to the second element of the third planetary gear set, that the third element of the second planetary gear set is connected via a third shaft to the second element of the first planetary gear set, that the first element of the first planetary gear set can be fixed to the housing via a first shaft when the first shift element is closed and can be connected to the second element of the second planetary gear set and to the crank shaft when the fourth shift element is locked, the third element of the first planetary gear set can be fixed to the housing via a second shaft when the second shift element is closed and can be connected to the first element of the second planetary gear set and to the third element of the third planetary gear set via a fourth shaft when the fifth shift element is locked, the first element of the third planetary gear set is detachably connected to the housing when the third shift element is locked in the first arrangement variant of the third shift element, and the third element of the third planetary gear set can be connected to the first element of the third planetary gear set via a fifth shaft as a first locking variant of the sixth shift element.Within the scope of the first coupling variant of the third planetary gear set, it is provided in a second blocking variant of the third planetary gear set in the bottom bracket transmission that the crank shaft is connected to the second element of the second planetary gear set, that the transmission output shaft is connected directly or additionally via a sixth shaft to the second element of the third planetary gear set, that the third element of the second planetary gear set is connected via a third shaft to the second element of the first planetary gear set, that the first element of the first planetary gear set can be fixed to the housing via a first shaft when the first shift element is closed and can be connected to the second element of the second planetary gear set and to the crank shaft when the fourth shift element is locked, the third element of the first planetary gear set can be fixed to the housing via a second shaft when the second shift element is closed and can be connected to the first element of the second planetary gear set and to the third element of the third planetary gear set via a fourth shaft when the fifth shift element is locked, the first element of the third planetary gear set is detachably connected to the housing when the third shift element is locked in the first arrangement variant of the third shift element, and the second element of the third planetary gear set can be connected to the first element of the third planetary gear set via the sixth shaft as a second blocking variant of the sixth shift element as a second blocking variant via a fifth shaft.Furthermore, in the context of the first coupling variant of the third planetary gear set, it is provided in a third blocking variant of the third planetary gear set in the bottom bracket transmission that the crank shaft is connected to the second element of the second planetary gear set, that the transmission output shaft is connected directly or additionally via a sixth shaft to the second element of the third planetary gear set, that the third element of the second planetary gear set is connected via a third shaft to the second element of the first planetary gear set, that the first element of the first planetary gear set can be fixed to the housing via a first shaft when the first shift element is closed and can be connected to the second element of the second planetary gear set and to the crank shaft when the fourth shift element is locked, the third element of the first planetary gear set can be fixed to the housing via a second shaft when the second shift element is closed and can be connected to the first element of the second planetary gear set via a fourth shaft when the fifth shift element is locked, the first element of the third planetary gear set is detachably connected to the housing when the third shift element is locked in the first arrangement variant of the third shift element, and the second element of the third planetary gear set can be connected to the third element of the third planetary gear set as a third locking variant in a third arrangement variant of the sixth shift element.In a second coupling variant of the second planetary gear set in the second transmission shift group of the proposed bottom bracket transmission, it is provided that the crank shaft is connected to the second element of the second planetary gear set, that the third element of the second planetary gear set is connected to the second element of the first planetary gear set via a third shaft, that the first element of the first planetary gear set is fixable to the housing via a first shaft when the first shift element is closed and is connectable to the second element of the second planetary gear set and to the crank shaft when the fourth shift element is locked, that the third element of the first planetary gear set is fixable to the housing via a second shaft when the second shift element is closed and is connectable to the first element of the second planetary gear set via a fourth shaft when the fifth shift element is locked, the third element of the third planetary gear set in the third arrangement variant of the sixth shift element is connectable to the first element of the second planetary gear set via the fourth shaft when the sixth shift element is closed, the first element of the third planetary gear set is connected to the housing via a fixed housing connection, and the second element of the third planetary gear set is detachably connected to the transmission output shaft when the third shift element is locked.Furthermore, in a third coupling variant of the second planetary gear set, it is provided in the second transmission shift group of the proposed bottom bracket transmission that the crank shaft is connected to the second element of the second planetary gear set, that the transmission output shaft is connected to the second element of the third planetary gear set directly or additionally via a sixth shaft, that the third element of the second planetary gear set is connected via a third shaft to the second element of the first planetary gear set, that the first element of the first planetary gear set can be fixed to the housing via a first shaft when the first shift element is closed and can be connected to the second element of the second planetary gear set and to the crank shaft when the fourth shift element is locked, the third element of the first planetary gear set is fixable to the housing via a second shaft when the second shift element is closed and is connectable to the first element of the second planetary gear set via a fourth shaft when the fifth shift element is locked, the first element of the third planetary gear set is connected to the housing via a fixed housing connection, and the third element of the third planetary gear set is connectable to the first element of the second planetary gear set in the third arrangement variant of the third shift element when the third shift element is locked and the third arrangement variant of the sixth shift element when the sixth shift element is closed is connectable to the first element of the second planetary gear set via the fourth shaft.Within the scope of the present invention, it is provided in the proposed bottom bracket transmission with the two transmission shift groups that the shift elements provided can be designed as brakes, freewheel brakes, clutches and / or freewheels. An advantageous embodiment variant of the invention provides that the first shifting element and the second shifting element are each designed as a form-fit brake, that the third shifting element is designed as a free-wheeling brake or free-wheeling, that the fourth shifting element and the fifth shifting element are each designed as free-wheeling and that the sixth shifting element is designed as a form-fit clutch.The shifting elements embodied as brakes and clutches are preferably embodied as form-locking shifting elements, for example as cost-effective brake claws or shifting claws or the like, for example with a toothed brake ring and a corresponding pawl. Brakes as shift elements have the advantage that they can be easily reached for actuation from the outside. In the case of clutches designed as freewheels, it is advantageous if the brakes are designed, for example, as one-way brakes, in order to prevent the transmission from blocking when the direction of rotation is reversed at the input or at the output. Preferably, non-actively switchable or actuatable freewheels are used as freewheels. This has the advantage that no switching actuation is required in the passive switching elements. The non-operable one-way clutch transmits a torque when it locks in the lock-up direction state. No torque is transmitted in the opposite direction of rotation, since the freewheel does not block in the overrun drive state. However, it is conceivable that actively switchable freewheels or also actively switchable freewheel brakes are also used.A preferred embodiment of the invention can provide that at least one of the planetary gear sets provided is designed as a minus planetary gear set, resulting in an arrangement which is particularly advantageous in terms of installation space. It is also conceivable for one of the planetary gear sets to be designed as a plus planetary gear set.A minus planetary gear set can preferably be transferred into a plus planetary gear set if the planetary gear carrier and ring gear connection on this gear set is interchanged with one another and the amount of the stationary transmission ratio is increased by 1. A minus planetary gear set has planetary gears rotatably mounted on its planetary gear carrier, which mesh with the sun gear and the ring gear of this planetary gear set, so that the ring gear rotates in the direction opposite to the sun gear rotation direction when the planetary gear carrier is held stationary and the sun gear rotates. A plus planetary gear set has inner and outer planetary gears rotatably mounted on its planetary gear carrier and in meshing engagement with one another, wherein the sun gear of this planetary gear set meshes with the inner planetary gears and the ring gear of this planetary gear set meshes with the outer planetary gears, so that the ring gear rotates in the same direction of rotation as the sun gear direction when the planetary gear carrier is held stationary and the sun gear rotates.This means for the person skilled in the art that in the individual gearsets designed as minus planetary gearsets, a first element or gearset element is designed as a sun gear, a second element is designed as a planet carrier or carrier, and a third element is designed as a ring gear. Furthermore, this means that in an individual gearset designed as a plus planetary gearset, the first element is designed as a sun gear, the second element is designed as a ring gear, and the third element is designed as a planet carrier or carrier.Furthermore, in the proposed bottom bracket transmission, it is conceivable that stepped planets are used both in a minus planetary gear set and in a plus planetary gear set. In the case of a minus stepped planetary gear set, the assignment of the elements or the gear set elements is maintained as in the case of a conventional minus planetary gear set. In a positive stepped planetary gearset, it is provided that the first element is designed as a first sun gear, the second element as a second sun gear and the third element as a planet carrier, or that the first element is designed as a first ring gear, the second element as a second ring gear and the third element as a planet carrier.In order to further optimize the control of the proposed bottom bracket transmission, it is provided that at least one torque sensor or the like is provided on the drive and / or on the output.In order to electrically support the drive in the proposed bottom bracket transmission, at least one electric machine or the like can be connected or connectable or permanently or releasably coupled to the drive or to the crank shaft or transmission input shaft and / or to the output or to the transmission output shaft. The electric machine can preferably be arranged axially parallel to the pedal crankshaft or transmission input shaft, while the planetary gear sets are arranged coaxially to the pedal crankshaft or transmission input shaft.A further aspect of the present invention claims a bicycle or pedelec with the above-described bottom bracket transmission. This results in the advantages and further advantages already described.The present invention is explained in more detail below with reference to the drawings. FIG. 1 shows a schematic principal view of a first coupling variant, not claimed, of a third planetary gear set of a second transmission shift group of a bottom bracket transmission on a bicycle or a pedelec with the second transmission shift group, connected downstream of a first transmission shift group, with a first blocking variant in the third planetary gear set; FIG. 2 shows a schematic principal view of a second coupling variant of the third planetary gear set of the second transmission shift group of the bottom bracket transmission with the first transmission shift group connected downstream of the first transmission shift group; FIG. 3 shows a schematic principal view of a third coupling variant of the third planetary gear set of the second transmission shift group of the bottom bracket transmission with the second transmission shift group connected downstream of the first transmission shift group; FIG. 4 shows a schematic principal view of the first coupling variant of the third planetary gear set of the second transmission shift group of the bottom bracket transmission with the second transmission shift group connected downstream of the first transmission shift group, with a second blocking variant in the third planetary gear set; FIG. 5 shows a schematic principal view of the first coupling variant of the third planetary gear set of the second transmission shift group of the bottom bracket transmission with the second transmission shift group connected downstream of the first transmission shift group, with a third blocking variant in the third planetary gear set; FIG. 6 shows a schematic principal view of the first coupling variant of the third planetary gear set of the second transmission shift group of the bottom bracket transmission according to the invention with the first transmission shift group connected downstream of the second transmission shift group with the first blocking variant in the third planetary gear set; FIG. 7 shows a schematic principal view of the first coupling variant of the third planetary gear set of the second transmission shift group of the bottom bracket transmission with the first transmission shift group connected downstream of the second transmission shift group with the second blocking variant in the third planetary gear set; FIG. 8 shows a schematic principal view of the first coupling variant of the third planetary gear set of the second transmission shift group of the bottom bracket transmission with the first transmission shift group connected downstream of the second transmission shift group with the third blocking variant in the third planetary gear set; FIG. 9 shows a shift pattern with eight shiftable gears of the bottom bracket transmission; FIG. 10 shows a schematic basic view of a planetary gear set as a minus planetary gear set; FIG. 11 shows a schematic basic view of a planetary gear set as a plus planetary gear set; FIG. 12 shows a schematic basic view of a planetary gear set as a minus stepped planetary gear set; FIG. 13 shows a schematic basic view of a planetary gear set as a plus stepped planetary gear set with two sun gears; FIG. 14 shows a schematic basic view of a planetary gear set as a plus stepped planetary gear set with two ring gears; FIG. 15 shows a schematic basic view of the bottom bracket transmission according to FIG. 1 with a torque sensor on the drive indicated by way of example; FIG. 16 shows a schematic basic view of the bottom bracket transmission according to FIG. 15 with an electric machine arranged by way of example on the drive; FIG. 17 shows a schematic basic view of the bottom bracket transmission according to FIG. 15 with an electric machine arranged by way of example on the output; and FIG. 18 shows a schematic basic view of the pedal bearing transmission according to FIG. 15 with a freewheel provided between the pedal crankshaft and the transmission input shaft.FIGS. 1 to 18 show various embodiments and designs or a shift pattern of a bottom bracket transmission according to the invention in planetary construction only by way of example. FIG. 1 shows, by way of example, a bicycle or pedelec 1 with the bottom bracket transmission, which is only indicated schematically.The pedal transmission is shown in a housing or pedal housing 2 with a pedal crankshaft or pedal crank with pedals, wherein the pedal crankshaft WAn is connected on the input side to one of the transmission shift groups 3, 4. Furthermore, the bottom bracket transmission comprises a transmission output shaft WAb as output with a chain wheel or belt wheel, not shown in any more detail. The bottom bracket transmission comprises a multi-stage first transmission shift group 3 and a multi-stage second transmission shift group 4, wherein the first transmission shift group 3 has a first planetary gear set RS 1 and a second planetary gear set RS 2, to which a first shift element B 1, a second shift element B 2, a fourth shift element K 1 and a fifth shift element K 2 are assigned, and wherein the second transmission shift group 4 has a third planetary gear set RS 3, to which a third shift element B 3, B 3 I, B 3 II and sixth shift element K 3, K 3 I, K 3 II are assigned. The two transmission shift groups 3, 4 form virtually two subtransmissions which can be interconnected with one another in any desired sequence with respect to the force flow direction between the pedal crankshaft WAn and the transmission output shaft WAb.Independently of the respective variant embodiments, the bottom bracket transmission provides that the crank shaft Wan is connected to a second element of the second planetary gear set RS 2 or to a third element of the third planetary gear set RS 3, that the transmission output shaft WAb is connected or connectable to a second element of the third planetary gear set RS 3 or is connected to a first element of the second planetary gear set RS 2, that a third element of the second planetary gear set RS 2 is connected to a second element of the first planetary gear set RS 1, that a first element of the first planetary gear set RS 1 can be fixed to a housing 2 via a first shift element B 1 and can be connected to at least the second element of the second planetary gear set via a fourth shift element K 1, a third element of the first planetary gear set RS 1 is fixable to the housing 2 via a second shift element B 2 and is connectable to at least the first element of the second planetary gear set RS 2 via a fifth shift element K 2, two elements of the third planetary gear set RS 3 are fixedly connected and one element of the third planetary gear set RS 3 is detachably connected, and in that, in a first arrangement variant of the third shift element B 3, a first element of the third planetary gear set is detachably connected to the housing 2 via the third shift element B 3, or in that, in a second arrangement variant of the third shift element B 3 I the second element of the third planetary gear set RS 3 is detachably connected to the transmission output shaft WAb via the fifth shift element B 3 I or in that, in a third arrangement variant of the fifth shift element B 3 II the third element of the third planetary gear set RS 3 is detachably connected to the first element of the second planetary gear set RS 2 via the fifth shift element B 3 II.In FIGS. 1 to 8, the three planetary gear sets RS 1, RS 2, RS 3 provided are each designed as minus planetary gear sets which are advantageous in terms of installation space. In this case, it is provided that a sun gear SR 1, SR 2, SR 3 is provided as the first element, a carrier or planet carrier PT 1, PT 2, PT 3 is provided as the second element, and a ring gear HR 1, HR 2, HR 3 is provided as the third element in the planetary gear sets RS 1, RS 2, RS 3.FIG. 1 shows the first coupling variant of the third planetary gear set RS 3 of the second transmission shift group 4 of the bottom bracket transmission with the first blocking variant, wherein the first transmission shift group 3 is connected upstream of the second transmission shift group 4. In detail, it is provided that the pedal crank shaft Wan is connected to the planet carrier PT 2 of the second planetary gear set RS 2, that the transmission output shaft WAb is connected to the planet carrier PT 3 of the third planetary gear set RS 3 via a sixth shaft W 6, that the ring gear HR 2 of the second planetary gear set RS 2 is connected to the planet carrier PT 1 of the first planetary gear set RS 1 via a third shaft W 3, the sun gear SR1 of the first planetary gear set RS1 can be fixed to the housing 2 via a first shaft W1 when the first shift element B1 is closed and can be connected to the planet carrier PT2 of the second planetary gear set RS2 and to the pedal crankshaft Wan when the fourth shift element K1 is locked, the ring gear HR1 of the first planetary gear set RS1 can be fixed to the housing 2 via a second shaft W2 when the second shift element B2 is closed and can be connected to the sun gear SR2 of the second planetary gear set RS2 and to the ring gear HR3 of the third planetary gear set RS3 via a fourth shaft W4, when the fifth shift element K2 is locked, that in the first arrangement variant of the third shift element B 3, the sun gear SR 3 of the third planetary gear set RS 3 is detachably connected to the housing 2 when the third shift element B 3 is locked, and that the ring gear HR 3 of the third planetary gear set RS 3 is connectable as a first blocking variant to the sun gear SR 3 of the third planetary gear set RS 3 via a fifth shaft B 5 in a first arrangement variant of the sixth shift element K 3.FIG. 2 shows a second coupling variant of the third planetary gear set RS 3 of the second transmission shift group 4 of the bottom bracket transmission, wherein the first transmission shift group 3 is connected upstream of the second transmission shift group 4. In detail, it is provided that the pedal crank shaft Wan is connected to the planet carrier PT 2 of the second planetary gear set RS 2, that the ring gear HR 2 of the second planetary gear set RS 2 is connected via the third shaft W 3 to the planet carrier PT 1 of the first planetary gear set RS 1, that the sun gear SR 1 of the first planetary gear set RS 1 can be fixed to the housing 2 via the first shaft W 1 when the first shift element B 1 is closed and can be connected to the planet carrier PT 2 of the second planetary gear set RS 2 and to the pedal crank shaft Wan when the fourth shift element K 1 is locked, the ring gear HR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the second shaft W2 when the second shift element B2 is closed and can be connected to the sun gear SR2 of the second planetary gear set RS2 via the fourth shaft W4 when the fifth shift element K2 is locked, the ring gear HR3 of the third planetary gear set RS3 in the third arrangement variant of the sixth shift element K3 II can be connected to the sun gear SR2 of the second planetary gear set RS2 via the fourth shaft W4 when the sixth shift element K3 is closed, and the sun gear SR3 of the third planetary gear set RS3 is connected to the housing 2 via a fixed housing connection W0, and in the second arrangement variant of the third shift element B 3 I the planet carrier PT 3 of the third planetary gear set RS 3 is detachably connected in I with the transmission output shaft WAb when the third shift element B 3 is locked.FIG. 3 shows a third coupling variant of the third planetary gear set RS 3 of the second transmission shift group 4 of the bottom bracket transmission, wherein the first transmission shift group 3 is connected upstream of the second transmission shift group 4. In detail, it is provided that the pedal crank shaft Wan is connected to the planet carrier PT 2 of the second planetary gear set RS 2, that the transmission output shaft WAb is connected to the planet carrier PT 3 of the third planetary gear set RS 3 via the sixth shaft W 6, that the ring gear HR 2 of the second planetary gear set RS 2 is connected to the planet carrier PT 1 of the first planetary gear set RS 1 via the third shaft W 3, the sun gear SR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the first shaft W1 when the first shift element B1 is closed and can be connected to the planet carrier PT2 of the second planetary gear set RS2 and to the pedal crankshaft Wan when the fourth shift element K1 is locked, the ring gear HR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the second shaft W2 when the second shift element B2 is closed and can be connected to the sun gear SR2 of the second planetary gear set RS2 when the fifth shift element K2 is locked, the sun gear SR3 of the third planetary gear set RS3 being connected to the housing 2 via a fixed housing connection W0, and in that, in the third arrangement variant of the third shift element B 3 II the ring gear HR 3 of the third planetary gear set RS 3 can be connected in II when the third shift element B 3 is locked and, in the third arrangement variant of the sixth shift element K 3 II when the sixth shift element K 3 is closed, in II via the fourth shaft W 4 to the sun gear SR 2 of the second planetary gear set RS 2.FIG. 4 shows a first coupling variant of the third planetary gear set RS 3 of the second transmission shift group 4 of the bottom bracket transmission with the second blocking variant, wherein the first transmission shift group 3 is connected upstream of the second transmission shift group 4. In detail, it is provided that the pedal crank shaft Wan is connected to the planet carrier PT 2 of the second planetary gear set RS 2, that the transmission output shaft WAb is connected to the planet carrier PT 3 of the third planetary gear set RS 3 via a sixth shaft W 6, that the ring gear HR 2 of the second planetary gear set RS 2 is connected to the planet carrier PT 1 of the first planetary gear set RS 1 via the third shaft W 3, the sun gear SR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the first shaft W1 when the first shift element B1 is closed and can be connected to the planet carrier PT2 of the second planetary gear set RS2 and to the pedal crankshaft Wan when the fourth shift element K1 is locked, the ring gear HR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the second shaft W2 when the second shift element B2 is closed and can be connected to the sun gear SR2 of the second planetary gear set RS2 and to the ring gear HR3 of the third planetary gear set RS3 via the fourth shaft W4 when the fifth shift element K2 is locked, that in the first arrangement variant of the third shift element B 3, the sun gear SR 3 of the third planetary gear set RS 3 is detachably connected to the housing 2 when the third shift element B 3 is locked, and that the planet carrier PT 3 of the third planetary gear set RS 3 is connectable via the sixth shaft W 6 in the second arrangement variant of the sixth shift element K 3 in I as a second blocking variant via the fifth shaft W 5 to the sun gear SR 3 of the third planetary gear set RS 3.FIG. 5 shows a first coupling variant of the third planetary gear set RS 3 of the second transmission shift group 4 of the bottom bracket transmission with the third blocking variant, wherein the first transmission shift group 3 is connected upstream of the second transmission shift group 4. In detail, it is provided that the pedal crank shaft Wan is connected to the planet carrier PT 2 of the second planetary gear set RS 2, that the transmission output shaft WAb is connected to the planet carrier PT 3 of the third planetary gear set RS 3 via the sixth shaft W 6, that the ring gear HR 2 of the second planetary gear set RS 2 is connected to the planet carrier PT 1 of the first planetary gear set RS 1 via the third shaft W 3, the sun gear SR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the first shaft W1 when the first shift element B1 is closed and can be connected to the planet carrier PT2 of the second planetary gear set and to the pedal crankshaft Wan when the fourth shift element K1 is locked, the ring gear HR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the second shaft W2 when the second shift element B2 is closed and can be connected to the sun gear SR2 of the second planetary gear set RS2 via the fourth shaft W4 when the fifth shift element K2 is locked, that in the first arrangement variant of the third shift element B 3, the sun gear SR 3 of the third planetary gear set RS 3 is detachably connected to the housing 2 when the third shift element B 3 is locked, and that the planet carrier PT 3 of the third planetary gear set RS 3 in the third arrangement variant of the sixth shift element K 3 is connectable in II as a third blocking variant to the ring gear HR 3 of the third planetary gear set RS 3.FIG. 6 shows the first coupling variant of the third planetary gear set RS 3 of the second transmission shift group 4 of the bottom bracket transmission with the first blocking variant, wherein the first transmission shift group 3 is arranged downstream of the second transmission shift group. In detail, it is provided that the pedal crank shaft Wan is connected to the ring gear HR 3 of the third planetary gear set RS 3, that the transmission output shaft WAb is connected to the sun gear SR 2 of the second planetary gear set RS 2 directly or via the fourth shaft W 4, that the ring gear HR 2 of the second planetary gear set RS 2 is connected via the third shaft W 3 to the planet carrier PT 1 of the first planetary gear set RS 1, the sun gear SR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the first shaft W1 when the first shift element B1 is closed and can be connected to the planet carrier PT3 of the third planetary gear set RS3 and to the planet carrier PT2 of the second planetary gear set RS2 when the fourth shift element K1 is locked, the ring gear HR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the second shaft W2 when the second shift element B2 is closed and can be connected to the sun gear SR2 of the second planetary gear set RS2 and to the transmission output shaft WAb when the fifth shift element K2 is locked, that in the first arrangement variant of the third shift element B 3, the sun gear SR 3 of the third planetary gear set RS 3 is detachably connected to the housing 2 when the third shift element B 3 is locked, and that the ring gear HR 3 of the third planetary gear set RS 3 in the first arrangement variant of the sixth shift element K 3 is connectable as a first locking variant via the fifth shaft B 5 to the sun gear SR 3 of the third planetary gear set RS 3.FIG. 7 shows the first coupling variant of the third planetary gear set RS 3 of the second transmission shift group 4 of the bottom bracket transmission with the second blocking variant, wherein the first transmission shift group 3 is arranged downstream of the second transmission shift group. In detail, it is provided that the pedal crank shaft Wan is connected to the ring gear HR 3 of the third planetary gear set RS 3, that the transmission output shaft WAb is connected to the sun gear SR 2 of the second planetary gear set RS 2 directly or via a quarter shaft W 4, that the ring gear HR 2 of the second planetary gear set RS 2 is connected via the third shaft W 3 to the planet carrier PT 1 of the first planetary gear set RS 1, the sun gear SR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the first shaft W1 when the first shift element B1 is closed and can be connected to the planet carrier PT2 of the second planetary gear set RS2 and to the planet carrier PT3 of the third planetary gear set RS3 when the fourth shift element K1 is locked, the ring gear HR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the second shaft W2 when the second shift element B2 is closed and can be connected to the sun gear SR2 of the second planetary gear set RS2 and to the transmission output shaft WAb when the fifth shift element K2 is locked, that in the first arrangement variant of the third shift element B 3, the sun gear SR 3 of the third planetary gear set RS 3 is detachably connected to the housing 2 when the third shift element B 3 is locked, and that the planet carrier PT 3 of the third planetary gear set RS 3 is connectable via the sixth shaft W 6 in the second arrangement variant of the sixth shift element K 3 in I as a second blocking variant via the fifth shaft W 5 to the sun gear SR 3 of the third planetary gear set RS 3.FIG. 8 shows the first coupling variant of the third planetary gear set RS 3 of the second transmission shift group 4 of the bottom bracket transmission with the third blocking variant, wherein the first transmission shift group 3 is arranged downstream of the second transmission shift group. In detail, it is provided that the pedal crank shaft Wan is connected to the ring gear HR 3 of the third planetary gear set RS 3, that the transmission output shaft WAb is connected to the sun gear SR 2 of the second planetary gear set RS 2 directly or via the fourth shaft W 4, that the ring gear HR 2 of the second planetary gear set RS 2 is connected via the third shaft W 3 to the planet carrier PT 1 of the first planetary gear set RS 1, the sun gear SR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the first shaft W1 when the first shift element B1 is closed and can be connected to the planet carrier PT2 of the second planetary gear set and to the planet carrier PT3 of the third planetary gear set RS3 when the fourth shift element K1 is locked, the ring gear HR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the second shaft W2 when the second shift element B2 is closed and can be connected to the sun gear SR2 of the second planetary gear set RS2 and to the transmission output shaft WAb via the fourth shaft W4, that in the first arrangement variant of the third shift element B 3, the sun gear SR 3 of the third planetary gear set RS 3 is detachably connected to the housing 2 when the third shift element B 3 is locked, and that the planet carrier PT 3 of the third planetary gear set RS 3 in the third arrangement variant of the sixth shift element K 3 is connectable in II as a third blocking variant to the ring gear HR 3 of the third planetary gear set RS 3.FIG. 9 shows a shift pattern for the bottom bracket transmission as an eight-speed transmission, wherein the first transmission shift group 3 is designed as a 4-speed group and the second transmission shift group 4 is designed as a 2-speed group, so that a total of eight speeds G 1, G 2, G 3, G 4, G 5, G 6, G 7, G 8 are realized. The shift pattern specifies the shift elements B 1, B 2, B 3, B 3 I, B 3 II, K 1, K 2, K 3, K 3 I, K 3 II used for the respective gear G 1, G 2, G 3, G 4, G 5, G 6, G 7, G 8. In this case, an X in the freewheels or the freewheel brake B 3, B 3 I, B 3 II, K 1, K 2 as shift elements in the shift pattern means that the freewheels or the freewheel brake block. This works automatically without external actuation. Furthermore, an X in the case of a brake B 1, B 2 and in the case of a clutch K 3, K 3 I, K 3 II as a shift element in the shift pattern means that the brake B 1, B 2 and the clutch K 3, K 3 I, K 3 II are closed. This functions via a suitable actuator system.In detail, it follows from the shift pattern according to FIG. 9 that, for the realization or shifting of a first gear G 1, the third shift element B 3, B 3 I, B 3 II, which is realized as a free-wheeling brake or free-wheeling, the fourth shift element K 1 and the fifth shift element K 2 which is realized as a free-wheeling, are blocked, that, for the realization of a second gear G 2, the first shift element B 1 which is realized as a brake is closed and the third shift element B 3, B 3 I, B 3 II which is realized as a free-wheeling brake or free-wheeling, and the fifth shift element K 2 which is realized as a free-wheeling, are blocked, wherein, for the realization of a third gear G3, the fourth shifting element K1 designed as a freewheel and the fifth shifting element K2 designed as a freewheel are locked, and the six shifting element K3, K3 I, K3 II designed as a clutch is closed, that, for the realization of a fourth gear G4, the first shifting element B1 designed as a brake is closed, and the fifth shifting element K2 designed as a freewheel is locked, and the sixth shifting element K3, K3 I, K3 II designed as a clutch is closed, that, for the realization of a fifth gear G5, the second shifting element B2 designed as a brake is closed, and the third shifting element B3 designed as a freewheel brake or freewheel is closed, B3 I, B3 II and the fourth shift element K1 designed as a freewheel are locked, that to realize a sixth gear G6, the first shift element B1 designed as a brake and the second shift element B2 designed as a brake are closed, and the third shift element B3, B3 I, B3 II designed as a freewheel brake or freewheel is locked, that to realize a seventh gear G7, the second shift element B2 designed as a brake is closed, and the fourth shift element K1 designed as a freewheel is locked, and the sixth shift element K3, K3 I, K3 II designed as a clutch is closed, and / or in that, in order to realize an eighth gear G 8, the first shift element B 1 designed as a brake and the second shift element B 2 designed as a brake are closed, and the fifth shift element K 3, K 3 I, K 3 II designed as a clutch is closed.FIG. 10 shows, by way of example, a minus planetary gear set in which the first element is designed as a sun gear 1-SR, the second element is designed as a planet carrier 2-PT and the third element is designed as a ring gear 3-HR.FIG. 11 shows, by way of example, a plus planetary gear set in which the first element is designed as a sun gear 1-SR, the second element is designed as a ring gear 2-HR and the third element is designed as a planet carrier 3-PT.FIG. 12 shows, by way of example, a minus stepped planetary gearset in which the first element is designed as sun gear 1-SR, the second element as planet carrier 2-PT and the third element as ring gear 3-HR.FIG. 13 shows, by way of example, a plus stepped planetary gearset in which the first element is designed as a first sun gear 1-SRA, the second element as a second sun gear 2-SRB and the third element as a planet carrier 3-PT.FIG. 14 shows, by way of example, a further embodiment of a positive stepped planetary gearset in which the first element is designed as a first ring gear 1-HRA, the second element as a second ring gear 2-HRB and the third element as a planet carrier 3-PT.The possible embodiments illustrated in FIGS. 10 to 14 with reference to a planetary gear set can be implemented on the specific planetary gear sets RS 1, RS 2, RS 3 of the bottom bracket transmission according to the invention.FIG. 15 shows an embodiment of the bottom bracket transmission according to the invention with reference to FIG. 1, in which a torque sensor 5 is connected or connectable to the pedal crankshaft or to the transmission input shaft WAn. For example, a disk-shaped torque sensor 5 can be arranged at the transmission input.However, the torque sensor 5 can also be implemented in a different manner.FIGS. 16 and 17 each show an embodiment of the bottom bracket transmission according to the invention with an additional electric machine EM on the basis of FIG. 15. The electric machine EM can be connected to the pedal crankshaft WAn, as is indicated in FIG. 16. It is also conceivable for the electric machine EM to be linked to the transmission output shaft WAb, as shown in FIG. 17. The electric machine EM is preferably arranged axially parallel to the pedal crankshaft or transmission input shaft Wan. However, a coaxial arrangement of the electric machine EM with respect to the pedal crankshaft would also be possible. Independently of this, it is advantageous to connect the electric machine EM via a freewheel F 0 or the like, so that no losses are caused by the co-rotating electric machine EM during operation without the electric machine EM.FIG. 18 shows an embodiment of the bottom bracket transmission according to the invention with reference to FIG. 15 with an additional freewheel F 1 between the crank and the transmission input of the bottom bracket transmission. In this way, in the event of a pedaling interruption, the freewheel can open and decouple the pedal crank from the inertial masses of the gear wheel set and in particular of the electric machine EM, so that no mass forces can be perceptible at the pedal.Reference numerals denote reference numerals1 Bicycle or Pedelec 2 Housing or bottom bracket housing 3 First transmission shift group 4 Second transmission shift group 5 Torque sensor EM Electric machine F 0 Freewheel for electric machine F 1 Additional freewheel SR 1 Sun gear of the first planetary gear set PT 1 Planet carrier of the first planetary gear set HR 1 Ring gear of the first planetary gear set SR 2 Sun gear of the second planetary gear set PT 2 Planet carrier of the second planetary gear set HR 2 Ring gear of the second planetary gear set SR 3 Sun gear of the third planetary gear set PT 3 Planet carrier of the third planetary gear set HR 3 Ring gear of the third planetary gear set RS 1 First planetary gear set RS 2 Second planetary gear set RS 3 Third planetary gear set WAn Transmission input shaft or bottom crank shaft WAb Transmission output shaft w1 first shaft W2 second shaft W3 third shaft W4 fourth shaft W5 fifth shaft W6 sixth shaft W0 fixed housing connection G1 first gear of the bottom bracket transmission G2 second gear of the bottom bracket transmission G3 third gear of the bottom bracket transmission G4 fourth gear of the bottom bracket transmission G5 fifth gear of the bottom bracket transmission G6 sixth gear of the bottom bracket transmission G7 seventh gear of the bottom bracket transmission G8 eighth gear of the bottom bracket transmission B1 first shifting element B2 second shifting element B3 third shifting element implemented as a freewheel brake in a first arrangement variant B3 I third shifting element implemented as freewheel In a third arrangement variant B3 II third shift element designed as a freewheel in a third arrangement variant K1, fourth shift element designed as a freewheel K2, fifth shift element designed as a freewheel K3, sixth shift element designed as a clutch in a first arrangement variant K3 I sixth shift element designed as a clutch in a second arrangement variant K3 II sixth shift element designed as a clutch in a third arrangement variant 1-SR, first element as sun gear 2-PT, second element as planet carrier 2-HR, second element as ring gear 3-HR, third element as ring gear 3-PT, third element as planet carrier 1-SRA, first element as first sun gear 2-SRB, second element as a second sun gear 1-HRA, first element as a first ring gear 2-HRB, first element as a second ring gear

Claims

Bottom bracket transmission in planetary construction for a bicycle or a pedelec (1), having a crank shaft (WAn) as drive and a transmission output shaft (WAb) as output and further shafts (W1, W2, W3, W4, W5, W6), having three planetary gear sets (RS1, RS2, RS3), and having six shift elements (B1, B2, B3, B3 I, B3 II, K1, K2, K3, K3 I, K3 II) for realizing a plurality of gears (G1, G2, G3, G4, G5, G6, G7, G8), wherein a first transmission shift group (3) and a second transmission shift group (4) are provided, wherein a first planetary gear set (RS1) and a second planetary gear set (RS2) and a first shift element (B1), a second shift element (B2), a fourth shift element (K1) and a fifth shift element (K2) are assigned to the first transmission shift group (4), wherein a third planetary gear set (RS3) and a third shift element (B3, B3 I, B3 II) and a sixth shift element (K3, K3 I, K3 II) are assigned to the second transmission shift group (4), wherein the pedal crank shaft (Wan) is connected to a second element of the second planetary gear set (RS2) or to a third element of the third planetary gear set (RS3), wherein the transmission output shaft (WAb) is connected or connectable to a second element of the third planetary gear set (RS3) or is connected to a first element of the second planetary gear set (RS2), wherein a third element of the second planetary gear set (RS2) is connected to a second element of the first planetary gear set (RS1), wherein a first element of the first planetary gear set (RS1) can be fixed to a housing (2) via a first shift element (B1) and can be connected to at least the second element of the second planetary gear set (RS2) via a fourth shift element (K1), wherein a third element of the first planetary gear set (RS 1) can be fixed to the housing (2) via a second shift element (B 2) and can be connected to at least the first element of the second planetary gear set (RS 2) via a fifth shift element (K 2), wherein two elements of the third planetary gear set (RS 3) are fixed and one element of the third planetary gear set (RS 3) is detachably connected, and either wherein, in a first arrangement variant of the third shift element (B3), a first element of the third planetary gear set is detachably connected to the housing (2) via the third shift element (B3), or wherein, in a second arrangement variant of the third shift element (B3 I) the second element of the third planetary gear set (RS3) is detachably connected to the transmission output shaft (WAb) via the fifth shift element (B3 I) or wherein, in a third arrangement variant of the fifth shift element (B3 II) the third element of the third planetary gear set (RS3) is detachably connected to the first element of the second planetary gear set (RS2) via the fifth shift element (B3 II) characterized in that, the pedal crank shaft (Wan) is connected to the second element of the second planetary gear set (RS2), the third element of the second planetary gear set (RS2) is connected via a third shaft (W3) to the second element of the first planetary gear set (RS1), the first element of the first planetary gear set (RS1) is fixable to the housing (2) via a first shaft (W1) when the first shift element (B1) is closed and, when the fourth shift element (K1) is locked, is still capable of being connected to the second element of the second planetary gear set (RS2) and to the pedal crank shaft (Wan), the third element of the first planetary gear set (RS1) can be fixed to the housing (2) via a second shaft (W2) when the second shift element (B2) is closed and can be connected to the first element of the second planetary gear set (RS2) via a fourth shaft (W4) when the fifth shift element (K2) is locked, the third element of the third planetary gear set (RS3) in the third arrangement variant of the sixth shift element (K3 II) can be connected to the first element of the second planetary gear set (RS2) via the fourth shaft (W4) when the sixth shift element (K3 II) is closed, and the first element of the third planetary gear set (RS3) is connected to the housing (2) via a fixed housing connection (W0), and that in the second arrangement variant of the third shift element (B3 I) the second element of the third planetary gear set (RS3) is detachably connected with the transmission output shaft (WAb) when the third shift element (B3 I) is locked (FIG. 2 ).Bottom bracket transmission in planetary construction for a bicycle or a pedelec (1), having a crank shaft (WAn) as drive and a transmission output shaft (WAb) as output and further shafts (W1, W2, W3, W4, W5, W6), having three planetary gear sets (RS1, RS2, RS3), and having six shift elements (B1, B2, B3, B3 I, B3 II, K1, K2, K3, K3 I, K3 II) for realizing a plurality of gears (G1, G2, G3, G4, G5, G6, G7, G8), wherein a first transmission shift group (3) and a second transmission shift group (4) are provided, wherein a first planetary gear set (RS1) and a second planetary gear set (RS2) and a first shift element (B1), a second shift element (B2), a fourth shift element (K1) and a fifth shift element (K2) are assigned to the first transmission shift group (4), wherein a third planetary gear set (RS3) and a third shift element (B3, B3 I, B3 II) and a sixth shift element (K3, K3 I, K3 II) are assigned to the second transmission shift group (4), wherein the pedal crank shaft (Wan) is connected to a second element of the second planetary gear set (RS2) or to a third element of the third planetary gear set (RS3), wherein the transmission output shaft (WAb) is connected or connectable to a second element of the third planetary gear set (RS3) or is connected to a first element of the second planetary gear set (RS2), wherein a third element of the second planetary gear set (RS2) is connected to a second element of the first planetary gear set (RS1), wherein a first element of the first planetary gear set (RS1) can be fixed to a housing (2) via a first shift element (B1) and can be connected to at least the second element of the second planetary gear set (RS2) via a fourth shift element (K1), wherein a third element of the first planetary gear set (RS 1) can be fixed to the housing (2) via a second shift element (B 2) and can be connected to at least the first element of the second planetary gear set (RS 2) via a fifth shift element (K 2), wherein two elements of the third planetary gear set (RS 3) are fixed and one element of the third planetary gear set (RS 3) is detachably connected, and either wherein, in a first arrangement variant of the third shift element (B3), a first element of the third planetary gear set is detachably connected to the housing (2) via the third shift element (B3), or wherein, in a second arrangement variant of the third shift element (B3 I) the second element of the third planetary gear set (RS3) is detachably connected to the transmission output shaft (WAb) via the fifth shift element (B3 I) or wherein, in a third arrangement variant of the fifth shift element (B3 II) the third element of the third planetary gear set (RS3) is detachably connected to the first element of the second planetary gear set (RS2) via the fifth shift element (B3 II) characterized in that, the pedal crank shaft (Wan) is connected to the second element of the second planetary gear set (RS2), the transmission output shaft (WAb) is connected to the second element of the third planetary gear set (RS3) directly or via a sixth shaft (W6), the third element of the second planetary gear set (RS2) is connected via a third shaft (W3) to the second element of the first planetary gear set (RS1), the first element of the first planetary gear set (RS1) can be fixed to the housing (2) via a first shaft (W1) when the first shift element (B1) is closed and can be connected to the second element of the second planetary gear set (RS2) and to the pedal crank shaft (Wan) when the fourth shift element (K1) is locked, the third element of the first planetary gear set (RS1) can be fixed to the housing (2) via a second shaft (W2) when the second shift element (B2) is closed and can be connected to the first element of the second planetary gear set (RS2) via a fourth shaft (W4) when the fifth shift element (K2) is locked, the first element of the third planetary gear set (RS 3) is connected to the housing (2) via a fixed housing connection (W 0), and in the third arrangement variant of the third shift element (B 3 II) the third element of the third planetary gear set (RS 3) is connectable to the first element of the second planetary gear set (RS 2) via the fourth shaft (W 4) when the third shift element (B 3 II) is locked and in the third arrangement variant of the sixth shift element (K 3 II) when the sixth shift element (K 3 II) is closed (FIG. 3 ).Bottom bracket transmission according to Claim 1 or 2, characterized in that the first transmission shift group (3) is arranged upstream or downstream of the second transmission shift group (4).Pedal transmission according to one of the preceding claims, characterized in that the first shifting element (B1) and the second shifting element (B2) are each designed as a form-fit brake, in that the third shifting element (B3, B3 I, B3 II) is designed as a freewheel brake or freewheel, in that the fourth shifting element (K1) and the fifth shifting element (K2) are each designed as a freewheel and / or in that the sixth shifting element (K3, K3 I, K3 II) is designed as a form-fit clutch.Bottom bracket transmission according to one of the preceding claims, characterized in that the first planetary gear set (RS1) and / or the second planetary gear set (RS2) and / or the third planetary gear set (RS3) is designed as a minus planetary gear set.Pedal transmission according to Claim 5, characterized in that, in the case of a minus planetary gear set, the first element is designed as a sun wheel (SR1, SR2, SR3), the second element is designed as a planet wheel carrier (PT1, PT2, PT3) and the third element is designed as a ring wheel (HR1, HR2, HR3).Bottom bracket transmission according to one of the preceding claims, characterized in that the first planetary gear set (RS1) and / or the second planetary gear set (RS2) and / or the third planetary gear set (RS3) is designed as a plus planetary gear set.Pedal transmission according to Claim 7, characterized in that, in the case of a positive planetary gear set, the first element is designed as a sun wheel (SR1, SR2, SR3), the second element is designed as a ring wheel (HR1, HR2, HR3) and the third element is designed as a planet wheel carrier (PT1, PT2, PT3).Pedal transmission according to one of the preceding claims, characterized in that a torque sensor (5) is connected to the pedal crankshaft (WAn).Pedal transmission according to one of the preceding claims, characterized in that at least one electric machine (EM) is connected or can be connected to the pedal crankshaft (WAn) or to the transmission output shaft (WAb).Pedal bearing transmission according to Claim 10, characterized in that the electric machine (EM) is arranged axially parallel to the pedal crankshaft (WAn).Pedal transmission according to one of the preceding claims, characterized in that, in order to realize a first gear (G1), the third shift element (B3, B3 I, B3 II), which is designed as a freewheel brake or freewheel, the fourth shift element (K1) which is designed as a freewheel and the fifth shift element (K2) which is designed as a freewheel are blocked, in that, in order to realize a second gear (G2), the first shift element (B1) which is designed as a brake is closed and the third shift element (B3, B3 I, B3 II) which is designed as a freewheel brake or freewheel and the fifth shift element (K2) which is designed as a freewheel are blocked, wherein, for realizing a third gear (G3), the fourth shifting element (K1), which is designed as a freewheel, and the fifth shifting element (K2), which is designed as a freewheel, are locked, and the six shifting element (K3, K3 I, K3 II) which is designed as a clutch is closed, that, for realizing a fourth gear (G4), the first shifting element (B1), which is designed as a brake, is closed, and the fifth shifting element (K2), which is designed as a freewheel, is locked, and the sixth shifting element (K3, K3 I, K3 II) which is designed as a clutch is closed, wherein, for realizing a fifth gear (G5), the second shifting element (B2) designed as a brake is closed and the third shifting element (B3, B3 I, B3 II) designed as a free-wheeling brake or free-wheeling clutch and the fourth shifting element (K1) designed as a free-wheeling clutch are locked, that, for realizing a sixth gear (G6), the first shifting element (B1) designed as a brake and the second shifting element (B2) designed as a brake are closed and the third shifting element (B3, B3 I, B3 II) designed as a free-wheeling brake or free-wheeling clutch is locked, wherein, for realizing a seventh gear (G7), the second shift element (B2) designed as a brake is closed and the fourth shift element (K1) designed as a freewheel is locked and the sixth shift element (K3, K3 I, K3 II) designed as a clutch is closed, and / or wherein, for realizing an eighth gear (G8), the first shift element (B1) designed as a brake and the second shift element (B2) designed as a brake are closed and the fifth shift element (K3, K3 I, K3 II) designed as a clutch is closed.Bicycle or pedelec (1) with the bottom bracket transmission according to one of the preceding claims.

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