Planetary bottom bracket gear for a bicycle or pedelec

Description

[0001] The present invention relates to a planetary gear bottom bracket transmission for a bicycle or pedelec, comprising a gear input shaft or crankshaft as the drive and a gear output shaft as the driven element, as well as further shafts, a first gear shifting unit with a stepped planetary gear set, and a second gear shifting unit, to which several shifting elements are assigned. The invention further relates to a bicycle or pedelec with the bottom bracket transmission. For example, a transmission in a crank housing for a bicycle or pedelec is known from German patent application DE 10 2022 203 243 B3. This transmission comprises a stepped planetary gear set and a further planetary gear set, which are arranged coaxially to the crankshaft, and to which six shifting elements are assigned for realizing six gears.

[0002] DE1022207261B3 discloses a generic bottom bracket gearbox.

[0003] The present invention is based on the objective of proposing a bottom bracket gearbox and a bicycle or pedelec with the bottom bracket gearbox, which have the lowest possible construction effort with improved properties compared to the prior art.

[0004] This problem is solved according to the invention by the features of claim 1 or 17. Advantageous and claimed embodiments are described in the dependent claims, the description, and the drawings.

[0005] A planetary bottom bracket gearbox for a bicycle or pedelec is therefore proposed. The bottom bracket gearbox has a crankshaft as the input and a gearbox output shaft as the output, as well as further shafts, with the output preferably being via a sprocket, a belt pulley, or the like.Furthermore, the bottom bracket transmission comprises a first gear shift group and a second gear shift group, which are coupled together to realize several gears, wherein the first gear shift group comprises a two-stage stepped planetary gear set to which three shifting elements are assigned, wherein a first shaft as input shaft of the first stepped planetary gear set is connected to a second ring gear as element of the first stepped planetary gear set, wherein a fifth shaft as output shaft of the first stepped planetary gear set is connected to a first ring gear as element of the first stepped planetary gear set, wherein a second sun gear as element of the first stepped planetary gear set is connected to a housing or via a first shifting element.is fixable to a stationary component or the like, wherein a first sun gear as an element of the first stepped planetary gear set can be fixed to the housing via a second switching element, wherein a stepped planetary gear carrier as an element of the first stepped planetary gear set is rotatably mounted, and wherein, for locking the stepped planetary gear set, two elements of the first stepped planetary gear set can be connected to each other via a fifth switching element, so that theoretically ten functionally equivalent locking variants are possible.

[0006] In this way, the aforementioned connection of the first gear shift group in the proposed bottom bracket gearbox, with its planned stepped planetary gear set and only three shifting elements, results in a particularly simple and compact design. Furthermore, the bottom bracket gearbox exhibits particularly low component loads and a significantly higher gear efficiency due to its geometric gear ratio series compared to conventional gearboxes.

[0007] For the mechanical connection of elements, for example rotary elements or the like of the two planetary gear sets in the two gear shift groups, additional shafts or shaft-like elements are preferably used besides the drive and driven elements, whereby the term shaft is not exclusively to be understood as a cylindrical, rotatably mounted machine element for the transmission of torques, but rather also as general connecting elements that connect the individual gear set elements to each other for torque transmission.

[0008] The axial order of the two gear groups can be reversed in the proposed bottom bracket gearbox. Accordingly, the first gear group can be positioned either upstream or downstream of the second gear group, between the gearbox input shaft (or crank arm) and the gearbox output shaft. With the first gear group positioned upstream, a crank arm connected to the gearbox input shaft (or crank arm) is effectively connected to the first shaft as the input shaft of the first gear group, and the fifth shaft of the first gear group is connected to the input of the second gear group. The crank arm and the first shaft can be manufactured as a single unit or in multiple parts.In a downstream arrangement of the first gear shift group, the first output shaft is connected to the second gear shift group, and the fifth shaft of the first gear shift group is connected to the transmission output shaft. The transmission output shaft and the fifth shaft can be manufactured as a single unit or in multiple parts.

[0009] In the proposed bottom bracket gearbox, an arbitrarily configured multi-speed second gear group can be combined with the first gear group to form the bottom bracket gearbox. Preferably, the second gear group can be configured as a two-speed gearbox, three-speed gearbox, or four-speed gearbox, and the first gear group as a three-speed gearbox, so that, for example, a six-speed, nine-speed, ten-speed, or twelve-speed gearbox can be realized as the bottom bracket gearbox. However, other numbers of gears can also be implemented in the gear groups, so that the bottom bracket gearbox can also have more or fewer gears. Depending on the boundary conditions and requirements of the bottom bracket gearbox, gears can also be omitted. In this way, the wheelset can be adapted to the required gear ratios (gear jumps, spread, etc.).) or also on the type of circuits, how many switching elements are involved.

[0010] To achieve a particularly simple and compact design of the bottom bracket gearbox, the second gearbox may be designed to include a first planetary gear set, to which a third and a sixth shifting element are assigned, wherein in the second gearbox a second element of the first planetary gear set is connected to the pedal crank shaft or to the fifth shaft as the output shaft of the first stepped planetary gear set, wherein a first element of the first planetary gear set can be fixed to the housing via the third shifting element, wherein a third element of the first planetary gear set is connected to the gearbox output shaft or to the first shaft as the input shaft of the first stepped planetary gear set, and wherein, to lock the first planetary gear set, two elements of the first planetary gear set can be connected to each other via the sixth shifting element.

[0011] One possible embodiment of the invention, for connecting the second gear shift group to achieve a particularly simple and compact design of the bottom bracket gearbox, provides that the second gear shift group comprises a first planetary gear set and a second planetary gear set, to which a third shifting element, a fourth shifting element and a sixth shifting element are assigned, wherein in the second gear shift group a second element of the first planetary gear set is connected to the pedal crank shaft or to the fifth shaft as the output shaft of the first stepped planetary gear set, wherein a first element of the first planetary gear set and a first element of the second planetary gear set are connected to the gearbox output shaft or to the first shaft as the input shaft of the first stepped planetary gear set, and wherein a third element of the first planetary gear set can be fixed to the housing via the third shifting element.wherein the third element of the first planetary gear set is connected to a second element of the second planetary gear set, wherein a third element of the second planetary gear set can be fixed to the housing via the fourth switching element, and wherein, in order to lock the first planetary gear set and the second planetary gear set, two elements of the planetary gear sets can be connected to each other via the sixth switching element.

[0012] In a further embodiment of the invention, for connecting the second gear shift group to achieve a particularly simple and compact design of the bottom bracket gearbox, the second gear shift group comprises a second stepped planetary gear set, to which a third shifting element, a fourth shifting element, and a sixth shifting element are assigned, wherein in the second gear shift group a second ring gear as an element of the second stepped planetary gear set is connected to the pedal crank shaft or to the fifth shaft as the output shaft of the first stepped planetary gear set, wherein a second ring gear as an element of the second stepped planetary gear set is connected to the gearbox output shaft or to the first shaft as the input shaft of the first stepped planetary gear set, wherein the stepped planetary gear carrier as an element of the second stepped planetary gear set can be fixed to the housing via the third shifting element.wherein a sun gear as an element of the second stepped planetary gear set can be fixed to the housing via the fourth switching element, and wherein, for locking the second stepped planetary gear set, two elements of the second stepped planetary gear set can be connected to each other via the sixth switching element.

[0013] In a further embodiment of the invention, for connecting the second gear shift group to achieve a particularly simple and compact design of the bottom bracket gearbox, the second gear shift group comprises a first planetary gear set and a second planetary gear set, to which a third shifting element, a fourth shifting element, a sixth shifting element and a seventh shifting element are assigned, wherein in the second gear shift group a second element of the first planetary gear set is connected to the pedal crank shaft or to the fifth shaft as the output shaft of the first stepped planetary gear set, wherein a first element of the first planetary gear set is connected to the gearbox output shaft or to the first shaft as the input shaft of the first stepped planetary gear set, and wherein a third element of the first planetary gear set is connected to a second element of the second planetary gear set.wherein a third element of the second planetary gear set can be fixed to the housing via the third switching element and can be connected to the pedal crank shaft or to the fifth shaft as the output shaft of the first stepped planetary gear set via the sixth switching element, and wherein a first element of the second planetary gear set can be fixed to the housing via the fourth switching element and can be connected to the transmission output shaft or to the first shaft as the input shaft of the first stepped planetary gear set via the seventh switching element.

[0014] Furthermore, another embodiment of the invention, for connecting the second gear shift group to achieve a particularly simple and compact design of the bottom bracket gearbox, provides that the second gear shift group comprises a first two-speed group and a second two-speed group, wherein the third and sixth shifting elements are assigned to the first two-speed group, and the fourth and seventh shifting elements are assigned to the second two-speed group. It is further provided that, in the first two-speed group, a second element of the first planetary gear set is connected to the pedal crank shaft or to the fifth shaft as the output shaft of the first stepped planetary gear set, that a third element of the first planetary gear set is connected to a second element of the second planetary gear set, and that a first element of the first planetary gear set can be fixed to the housing via the third shifting element.that, to lock the first planetary gear set, two elements of the first planetary gear set can be connected to each other via the sixth switching element; that a first element of the second planetary gear set is connected to the transmission output shaft or to the first shaft as the input shaft of the first stepped planetary gear set; that a third element of the second planetary gear set can be fixed to the housing via the fourth switching element; and that, to lock the second planetary gear set, two elements of the second planetary gear set can be connected to each other via the seventh switching element. In addition to reversing the order of the two transmission shift groups, it is also possible to reverse the two two-gear groups quasi-in the direction of power flow or in the axial direction.

[0015] Within the scope of the invention, the proposed bottom bracket transmission with the two gear shift groups provides that the shifting elements can be configured as brakes, freewheel brakes, clutches, and / or freewheels. An advantageous embodiment of the invention provides that the first, second, third, and fourth shifting elements are each configured as positive-locking brakes, and / or that the fifth, sixth, and seventh shifting elements are each configured as freewheels.

[0016] The switching elements designed as brakes are preferably implemented as positive-locking switching elements, for example, as cost-effective brake or shift claws or the like, for instance, with a toothed brake ring and a corresponding shift pawl. Brakes as switching elements have the advantage that they are easily accessible for external actuation. For clutches designed as freewheels, it is advantageous if the brakes are designed, for example, as single-acting brakes to prevent the transmission from locking up when the direction of rotation is reversed at the input or output. Preferably, non-actively switchable or actuated freewheels are used. This has the advantage that no switching actuation is required for the passive switching elements. The non-actuated freewheel transmits torque when it is locked in the locking position.No torque is transmitted in the opposite direction of rotation, as the freewheel does not lock in the overrunning position. However, it is conceivable that actively switchable freewheels or actively switchable freewheel brakes could also be used.

[0017] A preferred embodiment of the invention may provide that at least one of the planetary gear sets is designed as a negative planetary gear set, resulting in a particularly space-saving arrangement. It is also conceivable that one of the planetary gear sets is designed as a positive planetary gear set.

[0018] A negative planetary gear set can preferably be converted into a positive planetary gear set if the planet carrier and ring gear connections on this gear set are interchanged and the fixed gear ratio is increased by 1. A negative planetary gear set has planet gears rotatably mounted on its planet carrier, which mesh with the sun gear and the ring gear of this planetary gear set, such that the ring gear rotates in the opposite direction to the sun gear rotation when the planet carrier is fixed and the sun gear is rotating.A plus planetary gear set has inner and outer planet gears rotatably mounted on its planet carrier and meshing with each other, wherein the sun gear of this planetary gear set meshes with the inner planet gears and the ring gear of this planetary gear set meshes with the outer planet gears, so that the ring gear rotates in the same direction of rotation as the sun gear when the planet carrier is fixed and the sun gear is rotating.

[0019] For a person skilled in the art, this means that in single gear sets designed as a negative planetary gear set, the first element is a sun gear, the second element is a planet carrier or web, and the third element is a ring gear. Furthermore, this means that in a single gear set designed as a positive planetary gear set, the first element is a sun gear, the second element is a ring gear, and the third element is a planet carrier or web.

[0020] To further optimize the control of the proposed bottom bracket gearbox, it is planned that at least one torque sensor or similar device will be provided on the drive and / or the output.

[0021] To provide electrical assistance to the drive in the proposed bottom bracket gearbox, at least one electric machine or the like can be connected or connectable to the drive, i.e., to the crankshaft or gearbox input shaft, and / or to the output shaft or gearbox output shaft, either rigidly or detachably. Preferably, the electric machine can be arranged axially parallel to the crankshaft or gearbox input shaft, while the planetary gear sets are arranged coaxially to the crankshaft or gearbox input shaft.

[0022] Another aspect of the present invention claims a bicycle or pedelec with the aforementioned bottom bracket gearbox. This results in the advantages already described and further advantages.

[0023] The present invention will now be explained in more detail with reference to the drawings.

[0024] They show: Figure 1 a schematic principle view of a bottom bracket gearbox according to the invention on a bicycle or a pedelec with a first gearbox shift group upstream of a second gearbox shift group with a stepped planetary gear set with a first blocking variant; Figure 2 a schematic principle view of the bottom bracket transmission according to the invention with the first transmission shift group downstream of the second transmission shift group with the stepped planetary gear set with a first blocking variant; Figure 3a schematic principle view of the bottom bracket transmission according to the invention with the first transmission shift group upstream of the second transmission shift group with the stepped planetary gear set with a second blocking variant; Figure 4 a schematic principle view of the bottom bracket transmission according to the invention with the first transmission shift group upstream of the second transmission shift group with the stepped planetary gear set with a third blocking variant; Figure 5 a schematic principle view of the bottom bracket transmission according to the invention with the first transmission shift group upstream of the second transmission shift group with the stepped planetary gear set with a fourth blocking variant; Figure 6 a schematic principle view of the bottom bracket transmission according to the invention with the first transmission shift group upstream of the second transmission shift group with the stepped planetary gear set with a fifth blocking variant; Figure 7a schematic principle view of the bottom bracket transmission according to the invention with the first transmission shift group upstream of the second transmission shift group with the stepped planetary gear set with a sixth blocking variant; Figure 8 a schematic principle view of the bottom bracket transmission according to the invention with the first transmission shift group upstream of the second transmission shift group with the stepped planetary gear set with a seventh blocking variant; Figure 9 a schematic principle view of the bottom bracket transmission according to the invention with the first transmission shift group upstream of the second transmission shift group with the stepped planetary gear set with an eighth blocking variant; Figure 10 a shift pattern with three switchable gears of the first gear group in the bottom bracket gearbox; Figure 11a schematic principle view of the bottom bracket gearbox with a version of the second gearbox group, which is positioned upstream of the first gearbox group as a three-speed gearbox, as a two-speed gearbox; Figure 12 a shifting diagram of the six-speed bottom bracket gearbox according to Figure 11; Figure 13 a schematic principle view of the bottom bracket gearbox with a version of the second gearbox group with two planetary gear sets, which is connected downstream of the first gearbox group as a three-speed gearbox; Figure 14 a schematic principle view of the bottom bracket gearbox with a version of the second gearbox group, which is connected downstream of the first gearbox group as a three-speed gearbox, with a second stepped planetary gear set; Figure 15 a shifting diagram of the nine-speed bottom bracket gearbox according to Figures 13 and 14; Figure 16a schematic principle view of the bottom bracket gearbox with a version of the second gearbox group with two planetary gear sets, which is connected downstream of the first gearbox group as a three-speed gearbox; Figure 17 a shifting diagram of the ten-speed bottom bracket gearbox according to Figure 17; Figure 18 a schematic principle view of the bottom bracket gearbox with a version of the second gearbox group with two two-speed groups, which is connected downstream of the first gearbox group as a three-speed gearbox; Figure 19 a shifting diagram of the twelve-speed bottom bracket gearbox according to Figure 18; Figure 20 a schematic diagram of the bottom bracket gearbox according to Figure 1 with an exemplary torque sensor on the drive; Figure 21 a schematic diagram of the bottom bracket gearbox according to Figure 20 with an electric machine arranged at the drive as an example; Figure 22 a schematic diagram of the bottom bracket gearbox according to Figure 20 with an exemplary electric machine arranged at the output shaft; and Figure 23 a schematic diagram of the bottom bracket gearbox according to Figure 20 with a freewheel in front of the pedal crank axle.

[0025] In the Figures 1 to 23 The various design variants and versions or switching schemes of a planetary bottom bracket gearbox according to the invention are shown only as examples. Figure 1 Figure 1 shows, as an example, a bicycle or pedelec 1 with a bottom bracket gearbox, only schematically indicated.

[0026] The bottom bracket gearbox is shown in a housing or bottom bracket housing 2 with a crank arm and pedals as the crank arm shaft WAn, wherein the crank arm shaft WAn is connected on the input side to one of the gearbox shift groups 3, 4. Furthermore, the bottom bracket gearbox includes a gearbox output shaft WAb as the output with a chain or belt pulley (not shown) which is connected on the output side to one of the gearbox shift groups 3, 4. The bottom bracket gearbox comprises a multi-speed first gear shift group 3 and a multi-speed second gear shift group 4, wherein the first gear shift group 3 has a two-stage stepped planetary gear set StRS1, to which a first shifting element B1 is assigned as a positive-locking brake, a second shifting element B2 as a positive-locking brake and a fifth shifting element F1 I< , F1 II< , F1 III< , F1 1V< , F1 V< , F1 VI< , F1 VII< , F1 VIII< as a freewheel.The two gear shift groups 3, 4 essentially form two sub-gearboxes which can be switched together in any order with respect to the direction of power flow between pedal crank shaft WAn and gearbox output shaft WAb.

[0027] Regardless of the specific design variants, the bottom bracket gearbox is designed such that a first shaft W1, as the input shaft of the first stepped planetary gear set StRS1, is connected to a second ring gear HR1.2 as an element of the first stepped planetary gear set StRS1; that a fifth shaft W5, as the output shaft of the first stepped planetary gear set StRS1, is connected to a first ring gear HR1.1 as an element of the first stepped planetary gear set StRS1; that a second sun gear SR1.2, as an element of the first stepped planetary gear set StRS1, can be fixed to a housing 2 via the first switching element B1; that a first sun gear SR1.1 as an element of the first stepped planetary gear set StRS1 can be fixed to the housing 2 via the second switching element B2, that a stepped planetary gear carrier SPT1 as an element of the first stepped planetary gear set StRS1 is rotatably mounted, and that to lock the stepped planetary gear set StRS1 two elements of the first stepped planetary gear set StRS1 can be connected to each other via the fifth switching element F1 I< , F1 II< , F1 III< , F1 1V< , F1 V< , F1 VI< , F1 VII< , F1 VIII< .

[0028] In the Figure 11 , 13 , 14 , 16 and 18 The planned planetary gear sets RS1 and RS2 are each designed as space-saving minus planetary gear sets. It is provided that the first element in each set is a sun gear SR1 or SR2, the second element is a carrier or planetary gear carrier PT1 or PT2, and the third element is a ring gear HR1 or HR2.

[0029] In Figure 1Figure 1 shows a variant of the bottom bracket gearbox in which the first gear group 3 is upstream of the second gear group 4. In detail, the first variant is as follows: Figure 1It is provided that the first shaft W1 is connected to or formed integrally with the pedal crank shaft WAn as the input shaft of the first stepped planetary gear set StRS1 of the first gear shift group 3, that the first shaft W1 is connected to the second ring gear HR1.2 of the first stepped planetary gear set StRS1, that the first ring gear HR1.1 of the first stepped planetary gear set StRS1 is connected to the second gear shift group 4 via the fifth shaft W5 on the input side, that the stepped planetary gear carrier SPT1 of the first stepped planetary gear set StRS1 is rotatably mounted via a fourth shaft W4, that the second sun gear SR1.2 of the first stepped planetary gear set StRS1 can be fixed to the housing 2 via a second shaft W2 when the first shift element B1 is closed, that the first sun gear SR1.1 of the first stepped planetary gear set StRS1 can be fixed to the housing 2 via a third shaft W3 when the second switching element B2 is closed, and that, as a first locking variant for locking the first stepped planetary gear set StRS1, the first sun gear SR1.1 can be connected to the first ring gear HR1.1 when the fifth switching element F1 I< is locked in a first arrangement variant of the fifth switching element F1 I<.

[0030] In Figure 2 Figure 1 shows a variant of the bottom bracket gearbox in which the first gear group 3 is downstream of the second gear group 4. The details of this variant are as follows: Figure 2It is provided that the first shaft W1 is connected on the output side to the second gear shift group 4 as the input shaft of the first stepped planetary gear set StRS1, that the first shaft W1 is connected to the second ring gear HR1.2 of the first stepped planetary gear set StRS1, that the first ring gear HR1.1 of the first stepped planetary gear set StRS1 is connected to the fifth shaft W5, that the fifth shaft W5 is connected to the gear output shaft WAb as the output shaft of the first gear shift group or is formed integrally with it, that the stepped planetary gear carrier SPT1 of the first stepped planetary gear set StRS1 is rotatably mounted via the fourth shaft W4, that the second sun gear SR1.2 of the first stepped planetary gear set StRS1 can be fixed to the housing 2 via the second shaft W2 when the first shift element B1 is closed, that the first sun gear SR1.1 of the first stepped planetary gear set StRS1 can be fixed to the housing 2 via the third shaft W3 with the second switching element B2 closed, and that, as a first locking variant for locking the first stepped planetary gear set StRS1, the first sun gear SR1.1 can be connected to the first ring gear HR1.1 with the fifth switching element F1 I< locked in a first arrangement variant of the fifth switching element F1 I<.

[0031] In Figure 3 A second interlocking variant of the first stepped planetary gear set StRS1 is shown in the first gear shift group 3, which is upstream of the second gear shift group 4. In this second interlocking variant, with the fifth shift element F1 II< closed, the second sun gear SR1.2 is connected to the second ring gear HR1.2 of the first stepped planetary gear set StR1 in a second arrangement variant.

[0032] In Figure 4A third interlocking variant of the first stepped planetary gear set StRS1 is shown in the first gear shift group 3, which is upstream of the second gear shift group 4. In this third interlocking variant, with the fifth shift element F1 III< closed, the stepped planetary gear carrier SPT1 is connected to the second ring gear HR1.2 of the first stepped planetary gear set StR1 in a third arrangement variant.

[0033] In Figure 5 A fourth interlocking variant of the first stepped planetary gear set StRS1 is shown in the first gear shift group 3, which is upstream of the second gear shift group 4. In this fourth interlocking variant, with the fifth shift element F1 IV< closed, the first ring gear HR1.1 is connected to the second ring gear HR1.2 of the first stepped planetary gear set StR1 in a fourth arrangement variant.

[0034] In Figure 6A fifth interlocking variant of the first stepped planetary gear set StRS1 is shown in the first gear shift group 3, which is upstream of the second gear shift group 4. In this fifth interlocking variant, with the fifth shift element F1 V< closed, the first sun gear SR1.1 is connected to the second sun gear SR1.2 of the first stepped planetary gear set StR1 in a fifth arrangement variant.

[0035] In Figure 7 A sixth interlocking variant of the first stepped planetary gear set StRS1 is shown in the first gear shift group 3, which is upstream of the second gear shift group 4. In this sixth interlocking variant, with the fifth shift element F1 VI< closed, the second sun gear SR1.2 is connected to the stepped planetary gear carrier SPT1 of the first stepped planetary gear set StR1 in a sixth arrangement variant.

[0036] In Figure 8A seventh interlocking variant of the first stepped planetary gear set StRS1 is shown in the first gear shift group 3, which is upstream of the second gear shift group 4. In this seventh interlocking variant, with the fifth shift element F1 VII< closed, the first sun gear SR1.1 is connected to the stepped planetary gear carrier SPT1 of the first stepped planetary gear set StR1 in a seventh arrangement variant.

[0037] In Figure 9 An eighth interlocking variant of the first stepped planetary gear set StRS1 is shown in the first gear shift group 3, which is upstream of the second gear shift group 4. In this eighth interlocking variant, with the fifth shift element F1 VIII< closed, the first ring gear HR1.1 is connected to the stepped planetary gear carrier SPT1 of the first stepped planetary gear set StR1 in an eighth arrangement variant.

[0038] In Figure 10The diagram shows a shift pattern for the first gear group 3 as a three-speed transmission. This shows that three gears G1, G2, and G3 are possible with the first gear group 3. The shift pattern specifies the shift elements B1, B2, F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII< used for each gear G1, G2, and G3). An X next to the freewheel F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII< as a shift element in the diagram indicates that the freewheel is locked. This occurs automatically without external actuation. Furthermore, an X next to the brake B1 or B2 as a shift element in the diagram indicates that the brake B1 or B2 is engaged. This is achieved via suitable actuators. An empty field in the freewheel F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< means that it is not locked.An empty field for brakes B1, B2 means that they are open.

[0039] In detail, the circuit diagram results according to Figure 10 , that to realize or shift a first gear G1 the first shift element designed as a freewheel F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< locks, that to realize a second gear G2 the second shift element designed as a brake B2 is closed, and / or that to realize a third gear G3 the first shift element designed as a brake B1 is closed.

[0040] In Figure 11The bottom bracket gearbox is shown by way of example with a first gearbox switching group 3 as a three-speed gearbox group and with a second gearbox switching group 4 as a two-speed gearbox group with a first planetary gear set RS1, to which a third switching element B3 as a brake and a sixth switching element F2 as a freewheel are assigned.Specifically, the connection of the second gear shift group 4 to the first gear shift group 3 is provided as follows: the planet carrier PT1 of the first planet gear set RS1 is connected to the fifth shaft W5 as the output shaft of the first stepped planet gear set StRS1; the sun gear SR1 of the first planet gear set RS1 can be locked to the housing 2 via a sixth shaft W6 when the third shift element B3 is closed; the ring gear HR1 of the first planet gear set RS1 is connected to the transmission output shaft WAb; and, in one locking variant, the ring gear HR1 can be connected to the sun gear of the first planet gear set RS1 when the sixth shift element F2 is locked. The two further locking variants are achieved through the additional connection options of the elements of the first planet gear set RS1.The connections of the first stepped planetary gear set StRS1 to the first gear shift group 3 have already been described above.

[0041] In Figure 12 is a circuit diagram for the in Figure 11The bottom bracket gearbox shown depicts the first gear group 3 as a three-speed gearbox and the second gear group 4 as a two-speed gearbox. This results in 4 x 2, or six gears G1, G2, G3, G4, G5, G6 being possible. The shift diagram specifies the shift elements used for each gear G1, G2, G3, G4, G5, G6: B1, B2, B3, F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, F2. An X next to the freewheels F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, F2 in the shift diagram indicates that the freewheels are locked. This occurs automatically without external actuation. Furthermore, an X in the switching diagram for brakes B1, B2, B3 indicates that brakes B1, B2, B3 are closed. This is achieved via suitable actuators.An empty field for the freewheels F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< , F2 means that they are not locked. An empty field for the brakes B1, B2, B3 means that they are open.

[0042] In detail, the circuit diagram results according to Figure 12, that to realize or engage a first gear G1, the fifth shift element designed as a freewheel F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< ) and the sixth shift element designed as a freewheel F2 are locked, that to realize a second gear G2, the second shift element designed as a brake B2 is closed and the sixth shift element designed as a freewheel F2 is locked, that to realize a third gear G3, the first shift element designed as a brake B1 is closed and the sixth shift element designed as a freewheel F2 is locked, that to realize a fourth gear G4, the third shift element designed as a brake B3 is closed and the fifth shift element designed as a freewheel F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< locks,that to implement a fifth gear G5, the second switching element B2 and the third switching element B3, both designed as brakes, are closed, and / or that to implement a sixth gear G6, the first switching element B1 and the third switching element B3, both designed as brakes, are closed.

[0043] In Figure 13The bottom bracket gearbox is shown as an example with a first gear shift group 3 as a three-speed gear group and with a second gear shift group 4 as a three-speed gear group with a first planetary gear set RS1 and a second planetary gear set RS2, to which a third shift element B3 as a brake, a fourth shift element B4 as a brake, and a sixth shift element F2 as a freewheel are assigned. In detail, for the connection of the second gear shift group 4 to the first gear shift group 3, it is provided that the planet carrier PT1 of the first planetary gear set RS1 is connected to the fifth shaft W5 as the output shaft of the first stepped planetary gear set StRS1, that the sun gear SR1 of the first planetary gear set RS1 and the sun gear SR2 of the second planetary gear set RS2 are connected together to the gearbox output shaft WAb.that the ring gear HR1 of the first planetary gear set RS1 can be fixed to the housing 2 via a sixth shaft W6 when the third switching element B3 is closed, that the ring gear HR1 of the first planetary gear set RS1 is firmly connected to the planet carrier PT2 of the second planetary gear set RS2 via the sixth shaft W6, that the ring gear HR2 of the second planetary gear set RS2 can be fixed to the housing 2 via a seventh shaft W7 when the fourth switching element B4 is closed,and that, in order to lock the first planetary gear set RS1 and the second planetary gear set RS2 in a first locking variant, the transmission output shaft WAb, connected to the two sun gears SR1 and SR2 of the two planetary gear sets RS1 and RS2, can be connected, with the sixth shift element F2 locked, to the seventh shaft W7, connected to the ring gear HR2 of the second planetary gear set RS2, in a first arrangement variant. To implement the further locking variants, additional elements of the six components of the two planetary gear sets RS1 and RS2 are connected to each other via the sixth shift element F2. The connections of the first stepped planetary gear set StRS1 in the first transmission shift group 3 have already been described above.

[0044] In Figure 14The bottom bracket gearbox is shown by way of example with a first gear shift group 3 as a three-speed gear group and with a second gear shift group 4 as a three-speed gear group with a second stepped planetary gear set StRS2, to which a third shifting element B3 as a brake, a fourth shifting element B4 as a brake and a sixth shifting element F2 as a freewheel are assigned. In detail, for the connection of the second gear shift group 4 to the first gear shift group 3, it is provided that the second ring gear HR2.2 as an element of the second stepped planetary gear set StRS2 is connected to the fifth shaft W5 as the output shaft of the first stepped planetary gear set StRS1, that the first ring gear HR2.1 as an element of the second stepped planetary gear set StRS2 is connected to the transmission output shaft WAb; the stepped planetary gear carrier SPT2, as an element of the second stepped planetary gear set StRS2, can be fixed to the housing 2 via a sixth shaft W6 when the third switching element B3 is closed; the sun gear SR2.1, as an element of the second stepped planetary gear set StRS2, can be fixed to the housing 2 via a seventh shaft W7 when the fourth switching element B4 is closed; and, to lock the second stepped planetary gear set StRS2 in a first locking variant, the sun gear SR2.1 can be connected to the first ring gear HR2.1 of the second stepped planetary gear set StRS2 when the sixth switching element F2 is locked. Further locking variants are achieved through the additional connection options of the four elements of the second stepped planetary gear set StRS2.The connections of the first stepped planetary gear set StRS1 to the first gear shift group 3 have already been described above.

[0045] In Figure 15 is a circuit diagram for the in Figures 13 and 14The bottom bracket gearbox shown is depicted with the first gear shift group 3 as a three-speed gearbox and with the second gear shift group 4 as a three-speed gearbox. This results in 3 x 3, i.e., nine gears G1, G2, G3, G4, G5, G6, G7, G8, G9 being possible. The shift diagram indicates the shift elements used for each gear G1, G2, G3, G4, G5, G6, G7, G8, G9: B1, B2, B3, B4, F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, F2. In this context, an X for the freewheels F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, F2 as switching elements in the switching diagram indicates that the freewheels are locked. This occurs automatically without external actuation. Furthermore, an X for the brakes B1, B2, B3, B4 as switching elements in the switching diagram indicates that the brakes B1, B2, B3, B4 are closed. This is achieved via suitable actuators.An empty field for the freewheels F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< , F2 means that they are not locked. An empty field for the brakes B1, B2, B3, B4 means that they are open.

[0046] In detail, the circuit diagram results according to Figure 15, that to realize or engage a first gear G1, the fifth shift element designed as a freewheel F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< ) and the sixth shift element designed as a freewheel F2 are locked, that to realize a second gear G2, the second shift element designed as a brake B2 is closed and the sixth shift element designed as a freewheel F2 is locked, that to realize a third gear G3, the first shift element designed as a brake B1 is closed and the sixth shift element designed as a freewheel F2 is locked, that to realize a fourth gear G4, the fourth shift element designed as a brake B4 is closed and the fifth shift element designed as a freewheel F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< locks,that to realize a fifth gear G5, the second shift element B2 and the fourth shift element B4, both designed as brakes, are closed; that to realize a sixth gear G6, the first shift element B1 and the fourth shift element B4, both designed as brakes, are closed; that to realize a seventh gear G7, the third shift element B3, both designed as brakes, is closed and the fifth shift element F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, both designed as freewheels, is locked; that to realize an eighth gear G8, the second shift element B2 and the third shift element B3, both designed as brakes, are closed; and / or that to realize a ninth gear G9, the first shift element B1 and the third shift element B3, both designed as brakes, are closed.

[0047] In Figure 16The bottom bracket gearbox is shown as an example with a first gear shift group 3 as a three-speed gear group and with a second gear shift group 4 with a first planetary gear set RS1 and a second planetary gear set RS2, to which a third shift element B3 (brake), a fourth shift element B4 (brake), a sixth shift element F2 (freewheel), and a seventh shift element F3 (freewheel) are assigned. Specifically, the connection of the second gear shift group 4 to the first gear shift group 3 is provided as follows: the planet carrier PT1 of the first planetary gear set RS1 is connected to the fifth shaft W5 (output shaft of the first stepped planetary gear set StRS1); the sun gear SR1 of the first planetary gear set RS1 is connected to the gearbox output shaft WAb; and the ring gear HR1 of the first planetary gear set RS1 is rigidly connected to the planet carrier PT2 of the second planetary gear set RS2 via a sixth shaft W6.that the ring gear HR2 of the second planetary gear set RS2 can be locked to the housing 2 via a seventh shaft W7 when the third switching element B3 is closed, and that when the sixth switching element F2 is locked, it can be connected to the fifth shaft W5 as the output shaft of the first stepped planetary gear set StRS1; and that the sun gear SR2 of the second planetary gear set RS2 can be locked to the housing 2 via an eighth shaft W8 when the fourth switching element B4 is closed, and that when the seventh switching element F3 is locked, it can be connected to the transmission output shaft WAb. The connections of the first stepped planetary gear set StRS1 to the first transmission shift group 3 have already been described above.

[0048] In Figure 17 is a circuit diagram for the in Figure 16The bottom bracket gearbox shown depicts the first gear group 3 as a three-speed gearbox and the second gear group 4. This results in ten possible gears: G1, G2, G3, G4, G5, G6, G7, G8, G9, G10. The shift diagram indicates the shift elements used for each gear: B1, B2, B3, B4, F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, F2, F3. In this context, an X for the freewheels F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, F2, F3, as switching elements in the switching diagram, indicates that the freewheels are locked. This occurs automatically without external actuation. Furthermore, an X for the brakes B1, B2, B3, B4, as switching elements in the switching diagram, indicates that the brakes B1, B2, B3, B4 are closed. This is achieved via suitable actuators.An empty field for the freewheels F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< , F2, F3 means that they are not locked. An empty field for the brakes B1, B2, B3, B4 means that they are open.

[0049] In detail, the circuit diagram results according to Figure 17, that to realize or engage a first gear G1, the fifth freewheeling element F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< , the sixth freewheeling element F2 and the seventh freewheeling element F3 are locked, that to realize a second gear G2, the second brakeing element B2 is closed and the sixth freewheeling element F2 and the seventh freewheeling element F3 are locked, that to realize a third gear G3, the first brakeing element B1 is closed and the sixth freewheeling element F2 and the seventh freewheeling element F3 are locked, that to realize a fourth gear G4, the fourth brakeing element B4 is closed and the fifth freewheeling element F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< ,F1 VI< , F1 VII< , F1 VIII< and the sixth freewheel element F2 lock, so that to realize a fifth gear G5 the third brake element B3 is closed, and the fifth freewheel element F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< and the seventh freewheel element F3 lock, so that to realize a sixth gear G6 the second brake element B2 and the third brake element B3 are closed, and the seventh freewheel element F3 locks, so that to realize a seventh gear G7 the first brake element B1 and the third brake element B3 are closed, and the seventh freewheel element F3 locks,that to implement an eighth gear G8, the third shift element B3, designed as a brake, and the fourth shift element B4, designed as a brake, are closed, and the fifth shift element F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, designed as a freewheel, is locked; that to implement a ninth gear G9, the second shift element B2, the third shift element B3, and the fourth shift element B4, designed as a brake, are closed; and / or that to implement a tenth gear G10, the first shift element B1, the third shift element B3, and the fourth shift element B4, designed as a brake, are closed.

[0050] In Figure 18The bottom bracket gearbox is shown as an example with a first gear shift group 3 as a three-speed gear group and with a second gear shift group 4 as a first two-speed group and as a second two-speed group with a first planetary gear set RS1 and a second planetary gear set RS2, to which a third shift element B3 as a brake, a fourth shift element B4 as a brake, a sixth shift element F2 as a freewheel, and a seventh shift element F3 as a freewheel are assigned. In detail, for the connection of the second gear shift group 4 to the first gear shift group 3, it is provided that in the first two-speed group the planetary gear carrier PT1 of the first planetary gear set RS1 is connected to the fifth shaft W5 as the output shaft of the first stepped planetary gear set StRS1, that the ring gear HR1 of the first planetary gear set RS1 is connected via a seventh shaft W7 to the planetary gear carrier PT2 of the second planetary gear set RS2.that the sun gear SR1 of the first planetary gear set RS1 can be locked to the housing 2 via a sixth shaft W6 when the third switching element B3 is closed, that to lock the first planetary gear set RS1 in a first locking variant, the sun gear SR1 can be connected to the ring gear HR1 of the first planetary gear set RS1 when the sixth switching element F2 is locked in a first arrangement variant, wherein the further locking variants are realized by using the other elements in the first planetary gear set RS1 via the sixth switching element F2, that in the second two-speed group the sun gear SR2 of the second planetary gear set RS2 is connected to the transmission output shaft WAb, that the ring gear HR3 of the second planetary gear set RS2 can be locked to the housing 2 via an eighth shaft W8 when the fourth switching element B4 is closed,and that, in order to lock the second planetary gear set RS2 in a first locking variant, the sun gear SR2 can be connected to the ring gear HR2 of the second planetary gear set R2 in a first arrangement variant when the seventh switching element F3 is locked, with the further locking variants being realized by using the other elements of the second planetary gear set RS2 via the seventh switching element F3. The connections of the first stepped planetary gear set StRS1 to the first transmission shift group 3 have already been described above.

[0051] In Figure 19 is a circuit diagram for the in Figure 18The bottom bracket gearbox shown features the first gear group 3 as a three-speed gearbox and the second gear group 4 with two two-speed groups. This results in twelve possible gear ratios: G1, G2, G3, G4, G5, G6, G7, G8, G9, G10, G11, G12. The shift diagram indicates the shift elements used for each gear: B1, B2, B3, B4, F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, F2, F3. In this context, an X for the freewheels F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, F2, F3, as switching elements in the switching diagram, indicates that the freewheels are locked. This occurs automatically without external actuation. Furthermore, an X for the brakes B1, B2, B3, B4, as switching elements in the switching diagram, indicates that the brakes B1, B2, B3, B4 are closed. This is achieved via suitable actuators.An empty field for the freewheels F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< , F2, F3 means that they are not locked. An empty field for the brakes B1, B2, B3, B4 means that they are open.

[0052] In detail, the circuit diagram results according to Figure 19, that to realize or engage a first gear G1, the fifth freewheeling element F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< , the sixth freewheeling element F2 and the seventh freewheeling element F3 are locked, that to realize a second gear G2, the second brakeing element B2 is closed and the sixth freewheeling element F2 and the seventh freewheeling element F3 are locked, that to realize a third gear G3, the first brakeing element B1 is closed and the sixth freewheeling element F2 and the seventh freewheeling element F3 are locked, that to realize a fourth gear G4, the third brakeing element B3 is closed and the fifth freewheeling element F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< ,F1 VI< , F1 VII< , F1 VIII< and the seventh freewheel element F3 are locked, so that to realize a fifth gear G5 the second brake element B2 and the third brake element B3 as well as the seventh freewheel element F3 are locked, so that to realize a sixth gear G6 the first brake element B1 and the third brake element B3 are closed and the seventh freewheel element F3 is locked, so that to realize a seventh gear G7 the fourth brake element B4 is closed and the fifth freewheel element F1 I< , F1 II< , F1 III< , F1 IV< , F1 V< , F1 VI< , F1 VII< , F1 VIII< and the sixth freewheel element F2 are locked,that to realize an eighth gear G8, the second shift element B2 and the fourth shift element B4, both designed as brakes, are closed, and the sixth shift element F2, designed as a freewheel, is locked; that to realize a ninth gear G9, the first shift element B1 and the fourth shift element B4, both designed as brakes, are closed, and the sixth shift element F2, designed as a freewheel, is locked; that to realize a tenth gear G10, the third shift element B3 and the fourth shift element B4, both designed as brakes, are closed, and the fifth shift element F1 I<, F1 II<, F1 III<, F1 IV<, F1 V<, F1 VI<, F1 VII<, F1 VIII<, both designed as freewheels, is locked; that to realize an eleventh gear G11, the second shift element B2, the third shift element B3, and the fourth shift element B4, both designed as brakes, are closed Switching element B4 is closedand / or that, in order to realize a twelfth gear G12, the first switching element B1 designed as a brake, the third switching element B3 designed as a brake and the fourth switching element B4 designed as a brake are closed.

[0053] In Figure 20 is an embodiment of the bottom bracket gear according to the invention based on Figure 1 The figure shows a torque sensor 5 connected or connectable to the crank arm or the transmission input shaft WAn. For example, a disc-shaped torque sensor 5 can be arranged at the transmission input. However, the torque sensor 5 can also be designed in other ways.

[0054] In the Figure 21 and 22 Each embodiment of the bottom bracket drive according to the invention is based on Figure 20 with an additional electric machine EM. The electric machine EM can be connected to the pedal crank shaft WAn, as shown in Figure 21As indicated, it is also conceivable that the electric machine EM is connected to the transmission output shaft WAb, as shown in Figure 22. The electric machine EM is preferably arranged parallel to the crankshaft or transmission input shaft WAn. However, a coaxial arrangement of the electric machine EM to the crankshaft would also be possible. Regardless, it is advantageous to connect the electric machine EM via a freewheel F0 or the like, so that no losses are caused by the rotating electric machine EM when the vehicle is not operating.

[0055] In Figure 23 is an embodiment of the bottom bracket gear according to the invention based on Figure 20This is illustrated with an additional freewheel F between the crank arm and the gear input of the bottom bracket gearbox. In this way, when pedaling is interrupted, the freewheel can open and decouple the crank arm from the inertial masses of the gear set and, in particular, the electric motor EM, so that no inertial forces are felt at the pedal. Reference sign

[0056] 1 Bicycle or pedelec 2 Housing or bottom bracket housing 3 First gear group 4 Second gear group 5 Torque sensor EM Electric machine F0 Freewheel for electric machine F Additional freewheel SR1 Sun gear of the first planetary gear set PT1 Planetary gear carrier of the first planetary gear set HR1 Ring gear of the first planetary gear set SR2 Sun gear of the second planetary gear set PT2 Planetary gear carrier of the second planetary gear set HR2 Ring gear of the second planetary gear set SR1.1 First sun gear with larger number of teeth of the first stepped planetary gear set SR1.2 Second sun gear with smaller number of teeth of the first stepped planetary gear set HR1.1 First ring gear with larger number of teeth of the first stepped planetary gear set HR1.2 Second ring gear with smaller number of teeth of the first stepped planetary gear set SPT1 Stepped planetary gear carrier of the first stepped planetary gear set SR2.1 Sun gear of the second stepped planetary gear set HR2.1 first ring gear with larger number of teeth of the second stepped planetary gear setHR2.2 Second ring gear with smaller number of teeth of the second stepped planetary gear set SPT2 Stepped planetary gear carrier of the second stepped planetary gear set RS1 First planetary gear set RS2 Second planetary gear set StRS1 First stepped planetary gear set StRS2 Second stepped planetary gear set WAn Gearbox input shaft or pedal crank shaft WAb Gearbox output shaft W1 First shaft W2 Second shaft W3 Third shaft W4 Fourth shaft W5 Fifth shaft W6 Sixth shaft W7 Seventh shaft W8 Eighth shaft G1 First gear G2 Second gear G3 Third gear G4 Fourth gear G5 Fifth gear G6 Sixth gear G7 Seventh gear G8 Eighth gear G9 Ninth gear G10 Tenth gear G11 Eleventh gear G12 Twelfth gear B1 First shift element designed as a brake B2 Second shift element designed as a brake B3 Third shift element designed as a brake B4 Fourth as a brake executed switching element F1 I< fifth switching element designed as a freewheel in a first arrangement position F1 II< fifth switching element designed as a freewheel in a secondArrangement position F1 III< fifth switching element designed as a freewheel in a third arrangement position F1 IV< fifth switching element designed as a freewheel in a fourth arrangement position F1 V< fifth switching element designed as a freewheel in a fifth arrangement position F1 VI< fifth switching element designed as a freewheel in a sixth arrangement position F1 VII< fifth switching element designed as a freewheel in a seventh arrangement position F1 VIII< fifth switching element designed as a freewheel in an eighth arrangement position F2 sixth switching element designed as a freewheel F3 seventh switching element designed as a freewheel

Claims

1. Planetary bottom bracket gear for a bicycle or a pedelec (1), with a pedal crank shaft (WAn) as drive and a gear output shaft (WAb) as output and with further shafts (W1, W2, W3, W4, W5, W6, W7) and with a first gear shift group (3) and a second gear shift group (4), which are coupled to each other in order to realise multiple gears (G1, G2, G3, G4, G5, G6, G7, G8, G9, G10, G11, G12), wherein the first gear shift group (3) comprises a two-step multi-step planetary gear set (StRS1) which is assigned three shifting elements (B1, B2, F1I, F1II, F1III, F1IV, F1V, F1VI, F1VII, F1VIII), wherein a multi-step planetary gear carrier (SPT1) is rotatably mounted as an element of the first multi-step planetary gear set (StRS1), characterized in that a first shaft (W1) as an input shaft of the first multi-step planetary gear set (StRS1) is connected to a second ring gear (HR1.2) as an element of the first multi-step planetary gear set (StRS1), wherein a fifth shaft (W5) as the output shaft of the first multi-step planetary gear set (StRS1) is connected to a first ring gear (HR1.1) as an element of the first multi-step planetary gear set (StRS1), wherein a second sun gear (SR1.2) as an element of the first multi-step planetary gear set (StRS1) can be fixed to a housing (2) via a first shifting element (B1), wherein a first sun gear (SR1.1) as an element of the first multi-step planetary gear set (StRS1) can be fixed to the housing (2) via a second shifting element (B2), and wherein two elements of the first multi-step planetary gear set (StRS1) can be connected to each other via a fifth shifting element (F11, FI ", F1"1, F1IV, F1V, F1vI, F1vII, F1VIII) in order to block the multi-step planetary gear set (StRS1).

2. Bottom bracket gear according to Claim 1, characterized in that the first gear shift group (3) is connected upstream or downstream of the second gear shift group (4).

3. Bottom bracket gear according to either of the preceding claims, characterized in that the second gear shift group (4) comprises a first planetary gear set (RS1) which is assigned a third shifting element (B3) and a sixth shifting element (F2), wherein, in the case of the second gear shift group (4), a second element of the first planetary gear set (RS1) is connected to the pedal crank shaft (WAn) or to the fifth shaft (W5) as the output shaft of the first multi-step planetary gear set (StRS1), wherein a first element of the first planetary gear set (RS1) can be fixed to the housing (2) via the third shifting element (B3), wherein a third element of the first planetary gear set (RS1) is connected to the gear output shaft (WAb) or to the first shaft (W1) as the input shaft of the first multi-step planetary gear set (StRS1), and wherein two elements of the first planetary gear set (RS1) can be connected to each other via the sixth shifting element (F2) in order to block the first planetary gear set (RS1).

4. Bottom bracket gear according to either of Claims 1 and 2, characterized in that the second gear shift group (4) comprises a first planetary gear set (RS1) and a second planetary gear set (RS2), to which a third shifting element (B3), a fourth shifting element (B4) and a sixth shifting element (F2) are assigned, wherein, in the case of the second gear shift group (4), a second element of the first planetary gear set (RS1) is connected to the pedal crank shaft (WAn) or to the fifth shaft (W5) as the output shaft of the first multi-step planetary gear set (StRS1), wherein a first element of the first planetary gear set (RS1) and a first element of the second planetary gear set (RS2) are connected to the gear output shaft (WAb) or to the first shaft (W1) as the input shaft of the first multi-step planetary gear set (StRS1), wherein a third element of the first planetary gear set (RS1) can be fixed to the housing (2) via the third shifting element (B3), wherein the third element of the first planetary gear set (RS1) is connected to a second element of the second planetary gear set (RS2), wherein a third element of the second planetary gear set (RS2) can be fixed to the housing (2) via the fourth shifting element (B4), and wherein two shafts connected to elements of the planetary gear sets (RS1, RS2) can be connected to each other via the sixth shifting element (F2) in order to block the first planetary gear set (RS1) and the second planetary gear set (RS2).

5. Bottom bracket gear according to either of Claims 1 and 2, characterized in that the second gear shift group (4) comprises a second multi-step planetary gear set (StRS2), to which a third shifting element (B3), a fourth shifting element (B4) and a sixth shifting element (F2) are assigned, wherein, in the case of the second gear shift group (4), a second ring gear (HR2.2) is connected as an element of the second multi-step planetary gear set (StRS2) to the pedal crank shaft (WAn) or to the fifth shaft W5 as the output shaft of the first multi-step planetary gear set (StRS1), wherein a first ring gear (HR2.1) as an element of the second multi-step planetary gear set (StRS2) is connected to the gear output shaft (WAb) or to the first shaft (W1) as the input shaft of the first multi-step planetary gear set (StRS1), wherein a multi-step planetary gear carrier (SPT2) as an element of the second multi-step planetary gear set (StRS2) can be fixed to the housing (2) via the third shifting element (B3), wherein a sun gear (SR2.1) as an element of the second multi-step planetary gear set (StRS2) can be fixed to the housing (2) via the fourth shifting element (B4), and wherein two elements of the second multi-step planetary gear set (StRS2) can be connected to each other via the sixth shifting element (F2) in order to block the second multi-step planetary gear set (StRS2).

6. Bottom bracket gear according to either of Claims 1 and 2, characterized in that the second gear shift group (4) comprises a first planetary gear set (RS1) and a second planetary gear set (RS2), to which a third shifting element (B3), a fourth shifting element (B4), a sixth shifting element (F2) and a seventh shifting element (F3) are assigned, wherein, in the case of the second gear shift group (4), a second element of the first planetary gear set (RS1) is connected to the pedal crank shaft (WAn) or to the fifth shaft (W5) as the output shaft of the first multi-step planetary gear set (StRS1), wherein a first element of the first planetary gear set (RS1) is connected to the gear output shaft (WAb) or to the first shaft (W1) as the input shaft of the first multi-step planetary gear set (StRS1), wherein a third element of the first planetary gear set (RS1) is connected to a second element of the second planetary gear set (RS2), wherein a third element of the second planetary gear set (RS2) can be fixed to the housing (2) via the third shifting element (B3) and can be connected via the sixth shifting element (F2) to the pedal crank shaft (WAn) or to the fifth shaft (W5) as the output shaft of the first multi-step planetary gear set (StRS1), and wherein a first element of the second planetary gear set (RS2) can be fixed to the housing (2) via the fourth shifting element (B4) and can be connected via the seventh shifting element (F3) to the gear output shaft (WAb) or to the first shaft (W1) as the input shaft of the first multi-step planetary gear set (StRS1).

7. Bottom bracket gear according to either of Claims 1 and 2, characterized in that the second gear shift group (4) comprises a first two-gear group and a second two-gear group, wherein the first two-gear group is assigned the third shifting element (B3) and the sixth shifting element (F2), and wherein the second two-gear group is assigned the fourth shifting element (B4) and the seventh shifting element (F3).

8. Bottom bracket gear according to Claim 7, characterized in that, in the first two-gear group, a second element of the first planetary gear set (RS1) is connected to the pedal crank shaft (WAn) or to the fifth shaft (W5) as the output shaft of the first multi-step planetary gear set (StRS1), in that a third element of the first planetary gear set (RS1) is connected to a second element of the second planetary gear set (RS2), in that a first element of the first planetary gear set (RS1) can be fixed to the housing (2) via the third shifting element (B3), in that two elements of the first planetary gear set (RS1) can be connected to each other via the sixth shifting element (F2) in order to block the first planetary gear set (RS1), in that, in the first two-gear group, a first element of the second planetary gear set (RS2) is connected to the gear output shaft (WAb) or to the first shaft (W1) as the input shaft of the first multi-step planetary gear set (StRS1), in that a third element of the second planetary gear set (RS2) can be fixed to the housing (2) via the fourth shifting element (B4), and in that two elements of the second planetary gear set (RS2) can be connected to each other via the seventh shifting element (F3) in order to block the second planetary gear set (RS2).

9. Bottom bracket gear according to one of the preceding claims, characterized in that the first shifting element (B1), the second shifting element (B2), the third shifting element (B3) and the fourth shifting element (B4) are each designed as a positive engagement brake, and / or in that the fifth shifting element (F1I, F1II, F1III, F1IV, F1V, F1VI, F1VII, F1VIII), the sixth shifting element (F2) and the seventh shifting element (F3) are each configured as a freewheel.

10. Bottom bracket gear according to one of the preceding claims, characterized in that the first planetary gear set (RS1) and / or the second planetary gear set (RS2) are / is each designed as a minus planetary gear set.

11. Bottom bracket gear according to Claim 10, characterized in that, in the case of a minus planetary gear set, the first element is designed as a sun gear (SR1, SR2), the second element is designed as a planetary gear carrier (PT1, PT2) and the third element is designed as a ring gear (HR1, HR2).

12. Bottom bracket gear according to one of the preceding claims, characterized in that the first planetary gear set (RS1) and / or the second planetary gear set (RS2) are / is each designed as a plus planetary gear set.

13. Bottom bracket gear according to Claim 12, characterized in that, in the case of a plus planetary gear set, the first element is designed as a sun gear (SR1, SR2), the second element is designed as a ring gear (HR1, HR2) and the third element is designed as a planetary gear carrier (PT1, PT2).

14. Bottom bracket gear according to one of the preceding claims, characterized in that a torque sensor (5) is connected to the pedal crank shaft (WAn).

15. Bottom bracket gear 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 crank shaft (WAn) or to the gear output shaft (WAb).

16. Bottom bracket gear according to Claim 15, characterized in that the electric machine (EM) is arranged axially parallel to the pedal crank shaft (WAn).

17. Bicycle or pedelec (1) having the bottom bracket gear according to one of the preceding claims.