Bottom bracket transmission of planetary design for a bicycle or a pedelec

Abstract

The invention relates to a bottom bracket transmission of planetary design for a bicycle or pedelec (1), having a pedal crankshaft (WAn) as the drive input and a transmission output shaft (WAb) as the drive output and having further shafts (W1, W2, W3, W4, W5), and having a first transmission shifting assembly (3) and a second transmission shifting assembly (4) which are coupled to one another to implement a plurality of gears (G1, G2, G3, G4, G5, G6, G7), wherein the first transmission shifting assembly (3) comprises a two-stage stepped planet gear set (StRS) and the second transmission shifting assembly (4) comprises a planet gear set (RS) to which a first shifting element (B1), a second shifting element (B2), a third shifting element (B3, B3', B3''), a fourth shifting element (K1) and a fifth shifting element (K2, K21, K2") are assigned. The invention further relates to a bicycle or a pedelec (1) having a bottom bracket transmission.

Description

[0001] Planetary bottom bracket gear for a bicycle or pedelec

[0002] The present invention relates to a planetary bottom bracket gear for a bicycle or pedelec, comprising a transmission input shaft or pedal crankshaft as the input and a transmission output shaft as the output, as well as further shafts, a first transmission group with a stepped planetary gear set and a second transmission group with a planetary gear set, to which multiple shifting elements are assigned. Furthermore, the invention relates to a bicycle or pedelec with the bottom bracket gear.

[0003] For example, from publication DE 10 2022 203 243 B3, a transmission in a pedal crankcase for a bicycle or pedelec is known. The transmission comprises a stepped planetary gear set and another planetary gear set, which are arranged coaxially with the pedal crankshaft and are assigned six shifting elements to realize six gears.

[0004] The present invention is based on the object of proposing a bottom bracket gear and a bicycle or pedelec with the bottom bracket gear, which have the lowest possible construction effort with improved properties compared to the prior art.

[0005] This object is achieved according to the invention by the features of patent claims 1 and 17, respectively. Advantageous and claimed developments emerge from the subclaims and the description as well as the drawings.

[0006] Thus, a bottom bracket gear with a planetary design for a bicycle or pedelec is proposed. The bottom bracket gear has a pedal crankshaft as the input and a transmission output shaft as the output, as well as further shafts, wherein the output is preferably provided via a chain wheel, a belt wheel, or the like. Furthermore, the bottom bracket gear comprises a first gear shifting group and a second gear shifting group, which are coupled to one another to realize, for example, seven gears. The first gear shifting group comprises a two-stage stepped planetary gear set, and the second gear shifting group comprises a planetary gear set, to which a first shifting element, a second shifting element, a third shifting element, a fourth shifting element, and a fifth shifting element are assigned.wherein the pedal crankshaft is connected to a first sun gear of the stepped planetary gear set and the transmission output shaft is connected to a third element of the planetary gear set or can be connected via the third shifting element in a second arrangement variant of the third shifting element, or wherein the pedal crankshaft is connected to the third element of the planetary gear set and the transmission output shaft is connected to the first sun gear of the stepped planetary gear set, wherein a first ring gear of the stepped planetary gear set can be fixed to a housing or to any stationary component or the like via the first shifting element, wherein a second ring gear of the stepped planetary gear set can be fixed to the housing via the second shifting element,wherein a stepped planetary gear carrier of the stepped planetary gear set is connected to a second element of the planetary gear set or is connectable via the third shifting element in a third arrangement variant of the third shifting element, wherein a second sun gear of the stepped planetary gear set is connectable via the fourth shifting element to the transmission output shaft or to the pedal crankshaft, and wherein a first element of the planetary gear set is fixed to the housing or is fixable via the third shifting element in a first arrangement variant of the third shifting element to the housing.

[0007] The proposed bottom bracket transmission thus essentially consists of two gear shift groups or group transmissions, with the first gear shift group being, for example, a stepped planetary gear set, while the second gear shift group is, for example, a planetary gear set, so that a total of, for example, seven gears can be realized. However, different numbers of gears can also be realized in the gear shift groups, so that the bottom bracket transmission can also have more or fewer than, for example, eight gears. Depending on the boundary conditions and requirements of the bottom bracket transmission, gears can also be omitted. In this way, the gear set can be optimized for the required gear ratios (gear steps, gear spread, etc.) or for the type of shifting and how many shifting elements are involved.In this way, with the previously described connection of the stepped planetary gear set and the planetary gear set, and with only five shifting elements, a particularly simple and compact design is achieved for the proposed bottom bracket gear. In addition, the geometric gear ratio series of the bottom bracket gear results in particularly low component loads and an advantageously high gearing efficiency.

[0008] For the mechanical connection of elements, for example rotating elements or the like of the planetary gear sets, in addition to the input and output, further shafts or shaft-like elements are preferably used, whereby the term shaft does not exclusively refer to a cylindrical, rotatably mounted machine element for transmitting torque, but rather also to general connecting elements that connect the individual gear set elements to one another for torque transmission.

[0009] In the second gear shift group of the proposed bottom bracket transmission, various blocking variants of the planetary gear set are possible via a fifth shift element designed as a freewheel in three different arrangement variants of the fifth shift element.

[0010] Furthermore, in the second gear shift group of the proposed bottom bracket transmission, various coupling variants of the three elements of the planetary gear set are possible, of which a switchable coupling is realized via the third switching element designed as a brake or clutch, while the two remaining couplings are designed as fixed connections.

[0011] In the first coupling variant described below, the three blocking variants described above are also possible.

[0012] Accordingly, within the framework of the first coupling variant of the planetary gear set, in a first blocking variant of the planetary gear set in the bottom bracket transmission, it is provided that the pedal crankshaft is connected to a first sun gear of the stepped planetary gear set, that the transmission output shaft is connected to a third element of the planetary gear set, that the first ring gear of the stepped planetary gear set can be fixed to the housing via a first shaft when the first shifting element is locked, that the second ring gear of the stepped planetary gear set can be fixed to the housing via a second shaft when the second shifting element is closed, that the stepped planetary gear carrier of the stepped planetary gear set is connected to the second element of the planetary gear set via a fourth shaft, that the second sun gear of the stepped planetary gear set can be connected to the transmission output shaft via a fifth shaft when the fourth shifting element is closed,that the first element of the planetary gear set can be fixed to the housing via a third shaft when the third shifting element is closed in the first arrangement variant of the third shifting element, and that in order to block the planetary gear set in a first blocking variant, the first element of the planetary gear set can be connected to the third element of the planetary gear set when the fifth shifting element is locked in a first arrangement variant of the fifth shifting element.

[0013] With the proposed bottom bracket transmission, it is also possible to swap the connection between the drive shaft or crankshaft and the output shaft or transmission output shaft. Such a swap of drive and output has the advantage of resulting in the new gear ratios being the inverse of the old ones.

[0014] In detail, when exchanging input and output in the bottom bracket transmission, the connection is provided as follows: the pedal crankshaft is connected to the third element of the planetary gear set, the transmission output shaft is connected to the first sun gear of the stepped planetary gear set, the first ring gear of the stepped planetary gear set can be fixed to the housing via a first shaft when the first shifting element is locked, the second ring gear of the stepped planetary gear set can be fixed to the housing via a second shaft when the second shifting element is closed, the stepped planetary gear carrier of the stepped planetary gear set is connected to the second element of the planetary gear set via a fourth shaft, the second sun gear of the stepped planetary gear set can be connected to the pedal crankshaft via a fifth shaft when the fourth shifting element is closed,that the first element of the planetary gear set can be fixed to the housing via a third shaft when the third shifting element is closed in the first arrangement variant of the third shifting element, and that in order to block the planetary gear set in a first blocking variant, the first element of the planetary gear set can be connected to the third element of the planetary gear set when the fifth shifting element is locked in a first arrangement variant of the fifth shifting element.

[0015] Within the framework of the first coupling variant of the planetary gear set, in a second blocking variant of the planetary gear set in the bottom bracket transmission, it is provided that the pedal crankshaft is connected to a first sun gear of the stepped planetary gear set, that the transmission output shaft is connected to a third element of the planetary gear set, that the first ring gear of the stepped planetary gear set can be fixed to the housing via a first shaft when the first shifting element is locked, that the second ring gear of the stepped planetary gear set can be fixed to the housing via a second shaft when the second shifting element is closed, that the stepped planetary gear carrier of the stepped planetary gear set is connected to the second element of the planetary gear set via a fourth shaft, that the second sun gear of the stepped planetary gear set can be connected to the transmission output shaft via a fifth shaft when the fourth shifting element is closed,that the first element of the planetary gear set can be fixed to the housing via a third shaft when the third shifting element is closed in the first arrangement variant of the third shifting element, and that in order to block the planetary gear set in a second blocking variant, the first element of the planetary gear set can be connected to the second element of the planetary gear set when the fifth shifting element is locked in a second arrangement variant of the fifth shifting element.

[0016] Furthermore, within the framework of the first coupling variant of the planetary gear set, in a third blocking variant of the planetary gear set in the bottom bracket transmission, it is provided that the pedal crankshaft is connected to a first sun gear of the stepped planetary gear set, that the transmission output shaft is connected to a third element of the planetary gear set, that the first ring gear of the stepped planetary gear set can be fixed to the housing via a first shaft when the first shifting element is locked, that the second ring gear of the stepped planetary gear set can be fixed to the housing via a second shaft when the second shifting element is closed, that the stepped planetary gear carrier of the stepped planetary gear set is connected to the second element of the planetary gear set via a fourth shaft, that the second sun gear of the stepped planetary gear set can be connected to the transmission output shaft via a fifth shaft when the fourth shifting element is closed,that the first element of the planetary gear set can be fixed to the housing via a third shaft when the third shifting element is closed in the first arrangement variant of the third shifting element, and that in order to block the planetary gear set in a third blocking variant, the third element of the planetary gear set can be connected to the second element of the planetary gear set when the fifth shifting element is locked in a third arrangement variant of the fifth shifting element.

[0017] In a second coupling variant of the planetary gear set in the second gear shift group of the proposed bottom bracket transmission, it is provided that the pedal crankshaft is connected to a first sun gear of the stepped planetary gear set, that the transmission output shaft is connectable to the third element of the planetary gear set via a third shaft when the third shift element is engaged in the second arrangement variant of the third shift element, that the first ring gear of the stepped planetary gear set is fixable to the housing via a first shaft when the first shift element is locked, that the second ring gear of the stepped planetary gear set is fixable to the housing via a second shaft when the second shift element is engaged, that the stepped planetary gear carrier of the stepped planetary gear set is connected to the second element of the planetary gear set RS via a fourth shaft,that the second sun gear of the stepped planetary gear set is connectable to the transmission output shaft via a fifth shaft when the fourth shifting element is engaged, that the first element of the planetary gear set RS is fixed to the housing via a fixed housing connection, and that when the fifth shifting element is locked, in the third arrangement variant of the fifth shifting element, the transmission output shaft is connectable to the fourth shaft. Furthermore, in a third coupling variant of the planetary gear set in the second gear shift group of the proposed bottom bracket transmission, the pedal crankshaft is connected to a first sun gear of the stepped planetary gear set, that the transmission output shaft is connected to the third element of the planetary gear set, that the first ring gear of the stepped planetary gear set is fixable to the housing via a first shaft when the first shifting element is locked,that the second ring gear of the stepped planetary gear set can be fixed to the housing via a second shaft when the second shifting element is closed, that the stepped planetary gear carrier of the stepped planetary gear set can be connected to the second element of the planetary gear set via a fourth shaft when the third shifting element is closed in the third arrangement variant of the third shifting element, that the second sun gear of the stepped planetary gear set can be connected to the transmission output shaft via a fifth shaft when the fourth shifting element is closed, that the first element of the planetary gear set is fixed to the housing via a fixed housing connection, and that when the fifth shifting element is locked in the third arrangement variant of the fifth shifting element, the transmission output shaft can be connected to the fourth shaft.

[0018] Within the scope of the present invention, the proposed bottom bracket transmission with the two gear shift groups provides that the provided shifting elements can be designed as brakes, freewheel brakes, clutches, and / or freewheels. An advantageous embodiment of the invention provides that the first shifting element is designed as a freewheel brake or freewheel, that the second shifting element and the third shifting element are each designed as a positive-locking brake, that the fourth shifting element is designed as a positive-locking clutch, and / or that the fifth shifting element is designed as a freewheel.

[0019] The switching elements designed as brakes and clutches are preferably designed as positive-locking switching elements, for example as cost-effective brake or switching dogs or the like, for example with a toothed brake ring and a corresponding switching pawl. Brakes as switching elements have the advantage that they are easily accessible for operation 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 gear from jamming when the direction of rotation at the input or output is reversed. Freewheels that cannot be actively switched or actuated are preferably used as freewheels or freewheel brakes. This has the advantage that no switching operation is required for the passive switching elements. The non-actuable freewheel transmits a torque when it is locked in the blocking direction.No torque is transmitted in the opposite direction of rotation, as the freewheel does not lock in the overrunning drive state. However, it is conceivable that actively switchable freewheels or actively switchable freewheel brakes could also be used.

[0020] A preferred embodiment of the invention can provide for at least one of the planetary gear sets to be designed as a negative planetary gear set, resulting in a particularly space-efficient arrangement. It is also conceivable for one of the planetary gear sets to be designed as a positive planetary gear set.

[0021] 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 swapped and the amount of the stationary gear ratio is increased by 1. A negative planetary gear set has rotatably mounted planet gears on its planet carrier, which mesh with the sun gear and the ring gear of this planetary gear set, so that the ring gear rotates in the opposite direction to the sun gear rotation when the planet carrier is held stationary and the sun gear is rotating.A plus planetary gear set has inner and outer planetary gears that are rotatably mounted on its planetary gear carrier and mesh with one another, with the sun gear of this planetary gear set meshing with the inner planetary gears and the ring gear of this planetary gear set meshing with the outer planetary gears, so that the ring gear rotates in the same direction of rotation as the sun gear when the planetary gear carrier is held stationary and the sun gear is rotating.

[0022] For those skilled in the art, this means that in the case of single gear sets designed as a negative planetary gear set, a first element or gear set element is designed as a sun gear, a second element as a planetary gear carrier or web, and a third element as a ring gear. Furthermore, this means that in a single gear set designed as a positive planetary gear set, the first element is designed as a sun gear, the second element as a ring gear, and the third element as a planetary gear carrier or web.

[0023] In order to further optimize the control of the proposed bottom bracket gear, it is provided that at least one torque sensor or the like is provided on the drive and / or on the output.

[0024] To electrically assist the drive in the proposed bottom bracket transmission, at least one electric motor or the like can be connected or connectable to the drive or to the pedal crankshaft or transmission input shaft and / or to the output or to the transmission output shaft, or can be permanently or detachably coupled. Preferably, the electric motor can 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.

[0025] A further aspect of the present invention claims a bicycle or pedelec with the above-described bottom bracket gear. This results in the advantages already described and further advantages.

[0026] The present invention is further explained below with reference to the drawings.

[0027] Figure 1 is a schematic diagram of a first coupling variant of a planetary gear set of a second gear shifting group of a bottom bracket transmission according to the invention on a bicycle or a pedelec with the second gear shifting group as a planetary gear set connected downstream of a first gear shifting group as a stepped planetary gear set with a first blocking variant;

[0028] Figure 2 shows a schematic principle view of the first coupling variant of the planetary gear set of the second gear shift group of the bottom bracket transmission with the second gear shift group downstream of the first gear shift group as a planetary gear set with a second blocking variant; Figure 3 shows a schematic principle view of the first coupling variant of the planetary gear set of the second gear shift group of the bottom bracket transmission with the second gear shift group downstream of the first gear shift group as a planetary gear set with a third blocking variant;

[0029] Figure 4 is a schematic diagram of the first coupling variant with the first interlocking variant of the planetary gear set of the second gear shift group of the bottom bracket transmission with the second gear shift group connected downstream of the first gear shift group with an alternative arrangement of a third shift element in relation to the planetary gear set;

[0030] Figure 5 is a schematic diagram of a second coupling variant of the planetary gear set of the second gear shift group of the bottom bracket transmission with the first gear shift group connected downstream of the first gear shift group;

[0031] Figure 6 is a schematic diagram of a third coupling variant of the planetary gear set of the second gear shift group of the bottom bracket transmission with the second gear shift group connected downstream of the first gear shift group;

[0032] Figure 7 is a schematic diagram of the bottom bracket gear according to the invention with reversed connection of drive and output;

[0033] Figure 8 shows a gearshift diagram with eight switchable gears of the bottom bracket gearbox;

[0034] Figure 9 is a schematic diagram of a planetary gear set as a minus planetary gear set;

[0035] Figure 10 is a schematic diagram of a planetary gear set as a plus planetary gear set;

[0036] Figure 11 is a schematic diagram of a planetary gear set as a minus stepped planetary gear set; Figure 12 is a schematic diagram of a planetary gear set as a plus stepped planetary gear set with two sun gears;

[0037] Figure 13 is a schematic diagram of a planetary gear set as a plus-stepped planetary gear set with two ring gears;

[0038] Figure 14 is a schematic diagram of the bottom bracket gear according to Figure 1 with an exemplary torque sensor on the drive;

[0039] Figure 15 is a schematic diagram of the bottom bracket gear according to Figure 14 with an electric machine arranged on the drive as an example;

[0040] Figure 16 is a schematic diagram of the bottom bracket gear according to Figure 14 with an electric machine arranged as an example at the output; and

[0041] Figure 17 is a schematic diagram of the bottom bracket gear according to Figure 14 with a freewheel provided between the pedal crankshaft and the gear input shaft.

[0042] Figures 1 to 17 show various embodiments and designs, or a circuit diagram, of a planetary bottom bracket gear according to the invention, merely by way of example. Figure 1 shows an example of a bicycle or pedelec 1 with the bottom bracket gear, indicated only schematically.

[0043] The bottom bracket gear is shown in a housing or bottom bracket shell 2 with a pedal crank with pedals as the pedal crankshaft WAn, wherein the pedal crankshaft WAn is connected on the input side to one of the gear shift groups 3, 4. Furthermore, the bottom bracket gear comprises a gear output shaft WAb as the output with a chain or belt wheel (not shown in detail), which is connected on the output side to one of the gear shift groups 3, 4. The bottom bracket gear 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 StRS and the second gear shift group 4 has a planetary gear set RS, to which a first shifting element B1 acts as a freewheel brake, a second shifting element B2 acts as a positive-locking brake, a third shifting element B3, B3 1, B3" as a positive brake, a fourth switching element K1 as a positive clutch and a fifth switching element K2, K2 1 , K2" are assigned as a freewheel. The two gear shift groups 3, 4 essentially form two partial gears, which can be interconnected in any order with regard to the direction of power flow between the pedal crankshaft WAn and the gear output shaft WAb.

[0044] Regardless of the respective design variants, the bottom bracket transmission is provided with the pedal crankshaft WAn being connected to a first sun gear SR1.1 of the stepped planetary gear set StRS and the transmission output shaft WAb being connected to a third element of the planetary gear set RS or via the third switching element B3 1 in a second arrangement variant of the third switching element B3 1is connectable or that the pedal crankshaft WAn is connected to the third element of the planetary gear set RS and the transmission output shaft WAb is connected to the first sun gear SR1.1 of the stepped planetary gear set StRS, that a first ring gear HR1.1 of the stepped planetary gear set StRS can be fixed to a housing 2 via the first shifting element B1, that a second ring gear HR1.2 of the stepped planetary gear set StRS can be fixed to the housing 2 via the second shifting element B2, that a stepped planetary gear carrier SPT of the stepped planetary gear set StRS is connected to a second element of the planetary gear set RS or can be connected via the third shifting element B3" in a third arrangement variant of the third shifting element B3", that a second sun gear SR1.2 of the stepped planetary gear set StRS can be connected to the transmission output shaft WAb or to the pedal crankshaft WAn via the fourth switching element K1, and that a first element of the planetary gear set RS is fixed to the housing 2 or can be fixed to the housing 2 via the third switching element B3 in a first arrangement variant of the third switching element B3.

[0045] In Figures 1 to 7 and 14 to 17, the proposed planetary gear set RS is designed as a space-saving minus planetary gear set. In this case, the first element of the planetary gear set RS is a sun gear SR, the second element is a carrier or planetary gear carrier PT, and the third element is a ring gear HR.

[0046] Figure 1 shows an embodiment of the bottom bracket transmission in which the first gear shift group 3 is connected upstream of the second gear shift group 4, wherein a first clutch variant with a first blocking variant is shown in the second gear shift group 4. In detail, it is provided that the pedal crankshaft WAn is connected to the first sun gear SR1.1 of the stepped planetary gear set StRS, that the transmission output shaft WAb is connected to the ring gear HR of the planetary gear set RS, that the first ring gear HR1.1 of the stepped planetary gear set StRS can be fixed to the housing 2 via a first shaft W1 when the first shift element B1 is locked, that the second ring gear HR1.2 of the stepped planetary gear set StRS can be fixed to the housing 2 via a second shaft W2 when the second shifting element B2 is closed, that the stepped planetary gear carrier SPT of the stepped planetary gear set StRS is connected to the planetary gear carrier PT of the planetary gear set RS via a fourth shaft W4, that the second sun gear SR1.2 of the stepped planetary gear set StRS can be connected to the transmission output shaft WAb via a fifth shaft W5 when the fourth shifting element K1 is closed, that the sun gear SR of the planetary gear set RS can be fixed to the housing 2 via a third shaft W3 when the third shifting element B3 is closed in the first arrangement variant of the third shifting element B3, and that in order to block the planetary gear set RS in a first blocking variant, the sun gear SR of the planetary gear set RS can be connected to the ring gear HR of the planetary gear set RS when the fifth shifting element K2 is blocked in a first arrangement variant of the fifth shifting element K2.

[0047] Figure 2 shows an embodiment of the bottom bracket transmission in which the first gear shift group 3 is connected upstream of the second gear shift group 4, wherein the first coupling variant is shown with a second blocking variant in the second gear shift group 4. In detail, it is provided that the pedal crankshaft WAn is connected to the first sun gear SR1.1 of the stepped planetary gear set StRS, that the transmission output shaft WAb is connected to the ring gear HR of the planetary gear set RS, that the first ring gear HR1.1 of the stepped planetary gear set StRS can be fixed to the housing 2 via the first shaft W1 when the first shift element B1 is locked, that the second ring gear HR1.2 of the stepped planetary gear set StRS can be fixed to the housing 2 via the second shaft W2 when the second shifting element B2 is closed, that the stepped planetary gear carrier SPT of the stepped planetary gear set StRS is connected to the planetary gear carrier PT of the planetary gear set RS via the fourth shaft W4, that the second sun gear SR1.2 of the stepped planetary gear set StRS can be connected to the transmission output shaft WAb via the fifth shaft W5 when the fourth shifting element K1 is closed, that the sun gear SR of the planetary gear set RS can be fixed to the housing 2 via the third shaft W3 when the third shifting element B3 is closed in the first arrangement variant of the third shifting element B3, and that in order to block the planetary gear set RS in a second blocking variant, the sun gear SR of the planetary gear set RS with the fifth shifting element K2 locked. 1In a second arrangement variant, the fifth switching element K2 can be connected to the planetary gear carrier PT of the planetary gear set RS.

[0048] Figure 3 shows an embodiment of the bottom bracket transmission in which the first gear shift group 3 is connected upstream of the second gear shift group 4, wherein in the second gear shift group 4 the first coupling variant is shown with a third blocking variant. In detail it is provided that the pedal crankshaft WAn is connected to the first sun gear SR1.1 of the stepped planetary gear set StRS, that the transmission output shaft WAb is connected to the ring gear HR of the planetary gear set RS, that the first ring gear HR1.1 of the stepped planetary gear set StRS can be fixed to the housing 2 via the first shaft W1 when the first shift element B1 is locked, that the second ring gear HR1.2 of the stepped planetary gear set StRS can be fixed to the housing 2 via the second shaft W2 when the second switching element B2 is closed, that the stepped planetary gear carrier SPT of the stepped planetary gear set StRS is connected to the planetary gear carrier PT of the planetary gear set RS via the fourth shaft W4, that the second sun gear SR1.2 of the stepped planetary gear set StRS can be connected to the transmission output shaft WAb via the fifth shaft W5 when the fourth shifting element K1 is closed, that the sun gear SR of the planetary gear set RS can be fixed to the housing 2 via the third shaft W3 when the third shifting element B3 is closed in the first arrangement variant of the third shifting element B3, and that in order to block the planetary gear set RS in a third blocking variant, the ring gear HR of the planetary gear set RS can be connected to the planet gear carrier PT of the planetary gear set RS when the fifth shifting element K2 is locked in a third arrangement variant of the fifth shifting element K2.

[0049] In contrast to the design of the bottom bracket transmission shown in Figure 1, Figure 4 shows an alternative arrangement of the planetary gear set RS, in which the third shifting element B3 is arranged axially to the left of the planetary gear set RS in the drawing plane, and the connection between the stepped planetary carrier SPT of the stepped planetary gear set StRS and the planetary carrier PT of the planetary gear set RS runs radially below the planetary gear set RS. This connection can be used advantageously given design specifications and the level of the stationary gear ratio of the planetary gear set RS.

[0050] Figure 5 shows an embodiment of the bottom bracket transmission in which the first gear shift group 3 is connected upstream of the second gear shift group 4, with the second clutch variant being shown for the second gear shift group 4. In detail, it is provided that the pedal crankshaft WAn is connected to the first sun gear SR1.1 of the stepped planetary gear set StRS, that the transmission output shaft WAb is connected to the first sun gear SR1.1 of the stepped planetary gear set StRS when the third shift element B3 is closed. 1 in the second arrangement variant of the third switching element B3 1is connectable to the ring gear HR of the planetary gear set RS via the third shaft W3, that the first ring gear HR1.1 of the stepped planetary gear set StRS is fixable to the housing 2 via the first shaft W1 when the first shifting element B1 is locked, that the second ring gear HR1.2 of the stepped planetary gear set StRS is fixable to the housing 2 via the second shaft W2 when the second shifting element B2 is closed, that the stepped planetary gear carrier SPT of the stepped planetary gear set StRS is connected to the planetary gear carrier PT of the planetary gear set RS via the fourth shaft W4, that the second sun gear SR1.2 of the stepped planetary gear set StRS is connectable to the transmission output shaft WAb via the fifth shaft W5 when the fourth shifting element K1 is closed, that the sun gear SR of the planetary gear set RS is fixed to the housing 2 via a fixed housing connection WO, and that when the fifth shifting element K2 is locked in the third arrangement variant of the fifth

[0051] switching element K2" the transmission output shaft WAb can be connected to the fourth shaft W4.

[0052] Figure 6 shows an embodiment of the bottom bracket transmission in which the first gear shift group 3 is connected upstream of the second gear shift group 4, the third clutch variant being shown in the second gear shift group 4. In detail, it is provided that the pedal crankshaft WAn is connected to the first sun gear SR1.1 of the stepped planetary gear set StRS, that the transmission output shaft WAb is connected to the ring gear HR of the planetary gear set RS, that the first ring gear HR 1.1 of the stepped planetary gear set StRS can be fixed to the housing 2 via the first shaft W1 when the first shift element B1 is locked, that the second ring gear HR1.2 of the stepped planetary gear set StRS can be fixed to the housing 2 via the second shaft W2 when the second shifting element B2 is closed, that the stepped planetary gear carrier SPT of the stepped planetary gear set StRS can be connected to the planet gear carrier PT of the planetary gear set RS via the fourth shaft W4 when the third shifting element B3" is closed in the third arrangement variant of the third shifting element B3", that the second sun gear SR1.2 of the stepped planetary gear set StRS can be connected to the transmission output shaft WAb via the fifth shaft W5 when the fourth shifting element K1 is closed, that the sun gear SR of the planetary gear set RS is fixed to the housing 2 via the fixed housing connection WO, and that when the fifth shifting element K2" is locked in the third arrangement variant of the fifth shifting element K2", the transmission output shaft WAb can be connected to the fourth shaft W4.

[0053] Figure 7 shows a design of the bottom bracket gearbox in which the input and output are reversed. In detail, the pedal crankshaft WAn is connected to the ring gear HR of the planetary gear set RS, the gearbox output shaft WAb is connected to the first sun gear SR1.1 of the stepped planetary gear set StRS, the first ring gear HR1.1 of the stepped planetary gear set StRS can be fixed to the housing 2 via the first shaft W1 when the first shifting element B1 is locked, the second ring gear HR1.2 of the stepped planetary gear set StRS can be fixed to the housing 2 via the second shaft W2 when the second shifting element B2 is closed, the stepped planetary gear carrier SPT of the stepped planetary gear set StRS is connected to the planet gear carrier PT of the planetary gear set RS via the fourth shaft W4, the second sun gear SR1.2 of the stepped planetary gear set StRS can be connected to the pedal crankshaft WAn via the fifth shaft W5 when the fourth shifting element K1 is closed, that the sun gear SR of the planetary gear set RS can be fixed to the housing 2 via the third shaft W3 when the third shifting element B3 is closed in the first arrangement variant of the third shifting element B3, and that in order to block the planetary gear set RS in the first blocking variant, the sun gear SR of the planetary gear set RS can be connected to the ring gear HR of the planetary gear set RS when the fifth shifting element K2 is locked in the first arrangement variant of the fifth shifting element K2.

[0054] Figure 8 shows a shifting diagram for the bottom bracket gear as a seven-speed transmission, so that a total of seven gears G1, G2, G3, G4, G5, G6, G7 are realized. In the shifting diagram, the shifting elements B1, B2, B3, B3 used for the respective gear G1, G2, G3, G4, G5, G6, G7 are shown. 1 , B3", K1 , K2, K21 , K2". Here, an X in the freewheel or freewheel brake B1 , K2, K2 1 , K2" as switching elements in the circuit diagram that lock the freewheels or the freewheel brake. This works automatically without external activation. Furthermore, an X for a brake B2, B3 and for a clutch K1 as a switching element in the circuit diagram means that the brake B2, B3 and the clutch K1 are closed. This works via a suitable actuator. An empty field for the freewheel or the freewheel brake B1, K2, K2 1 "K2" as switching elements in the circuit diagram indicates that these are not locked. An empty field for the brakes B2, B3 and the clutch K1 in the circuit diagram means that these are open.

[0055] In detail, the switching diagram according to Figure 8 shows that in order to implement or switch a first gear G1, the first switching element B1 designed as a freewheel brake and the fifth switching element K2 designed as a freewheel, K2 1 , K2" block that to realize a second gear G2 the second switching element B2 designed as a brake is closed and the fifth switching element K2, K2 designed as a freewheel 1 , K2" blocks that in order to realize a third gear G3, the first switching element B1 designed as a freewheel brake blocks and the third switching element B3 designed as a brake, B3 1 , B3" is closed, that to realize a fourth gear G4 the second switching element B2 designed as a brake and the third switching element B3 designed as a brake, B3 1, B3" are closed, that to realize a fifth gear G5 the fourth switching element K1 designed as a clutch is closed and the fifth switching element K2 designed as a freewheel, K2 1 , K2" blocks the third switching element B3, B3, designed as a brake, in order to realize a sixth gear G6. 1 , B3" and the fourth switching element K1 designed as a clutch are closed, and / or that in order to realize a seventh gear G7 the second switching element B2 designed as a brake and the fourth switching element K1 designed as a clutch are closed.

[0056] Figure 9 shows an example of a minus planetary gear set in which the first element is designed as a sun gear 1-SR, the second element as a planet gear carrier 2-PT and the third element as a ring gear 3-HR.

[0057] Figure 10 shows an example of a plus planetary gear set in which the first element is designed as a sun gear 1-SR, the second element as a ring gear 2-HR and the third element as a planet gear carrier 3-PT.

[0058] Figure 11 shows an example of a minus-stepped planetary gear set in which the first element is designed as a sun gear 1-SR, the second element as a planet gear carrier 2-PT and the third element as a ring gear 3-HR.

[0059] Figure 12 shows an example of a plus-stepped planetary gear set in which the first element is designed as the first sun gear 1-SRA, the second element as the second sun gear 2-SRB and the third element as the planet gear carrier 3-PT.

[0060] Figure 13 shows an example of another embodiment of a plus-step planetary gear set, in which the first element is designed as the first ring gear 1-HRA, the second element as the second ring gear 2-HRB, and the third element as the planetary gear carrier 3-PT. The possible embodiments illustrated in Figures 9 to 13 using a planetary gear set can be implemented on the specific planetary gear set RS of the bottom bracket transmission according to the invention.

[0061] Figure 14 shows an embodiment of the bottom bracket transmission according to the invention based on Figure 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 designed in a different way.

[0062] Figures 15 and 16 each show an embodiment of the bottom bracket gear according to the invention based on Figure 14 with an additional electric machine EM. The electric machine EM can be connected to the pedal crankshaft WAn, as indicated in Figure 15. It is also conceivable for the electric machine EM to be connected to the transmission output shaft WAb, as shown in Figure 16. 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 to the pedal crankshaft would also be possible. Irrespective of this, it is advantageous to connect the electric machine EM via a freewheel FO or the like so that no losses are caused by the co-rotating electric machine EM during operation without the electric machine EM.

[0063] Figure 17 shows an embodiment of the bottom bracket transmission according to the invention based on Figure 15, with an additional freewheel F1 between the pedal crank and the transmission input of the bottom bracket transmission. This allows the freewheel to open when pedaling is interrupted, decouples the pedal crank 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 numeral

[0064] 1 bicycle or pedelec

[0065] 2 Housing or bottom bracket shell

[0066] 3 first gearshift group

[0067] 4 second gearshift group

[0068] 5 Torque sensor

[0069] EM electric machine

[0070] FO freewheel for electric machine

[0071] F1 additional freewheel

[0072] SR sun gear of the planetary gear set

[0073] PT planetary gear carrier of the planetary gear set

[0074] HR ring gear of the planetary gear set

[0075] RS planetary gear set

[0076] SR1.1 first sun gear with smaller number of teeth of the stepped planetary gear set

[0077] SR1.2 second sun gear with larger number of teeth of the stepped planetary gear set

[0078] HR1.1 first ring gear with smaller number of teeth of the stepped planetary gear set

[0079] HR1.2 second ring gear with larger number of teeth of the stepped planetary gear set

[0080] SPT stepped planetary gear carrier of the stepped planetary gear set

[0081] StRS stepped planetary gear set

[0082] WAn gearbox input shaft or crankshaft

[0083] WAB gearbox output shaft

[0084] W1 first wave

[0085] W2 second wave

[0086] W3 third wave

[0087] W4 fourth wave

[0088] W5 fifth wave

[0089] WO fixed housing connection

[0090] G1 first gear of the bottom bracket gearbox

[0091] G2 second gear of the bottom bracket gearbox

[0092] G3 third gear of the bottom bracket gearbox

[0093] G4 fourth gear of the bottom bracket gearbox

[0094] G5 fifth gear of the bottom bracket gear G6 sixth gear of the bottom bracket gear

[0095] G7 seventh gear of the bottom bracket gearbox

[0096] B1 first switching element designed as a freewheel brake

[0097] B2 second switching element designed as a brake

[0098] B3 third switching element designed as a brake in a first arrangement variant

[0099] B3 1 third switching element designed as a freewheel in a second arrangement variant

[0100] B3" third switching element designed as a freewheel in a third arrangement variant

[0101] K1 fourth switching element designed as a clutch

[0102] K2 fifth switching element designed as a freewheel in a first arrangement variant

[0103] K2 1 fifth switching element designed as a freewheel in a second arrangement variant

[0104] K2" fifth switching element designed as a freewheel in a third arrangement variant

[0105] 1-SR first element as sun gear

[0106] 2-PT second element as planetary gear carrier

[0107] 2-HR second element as ring gear

[0108] 3-HR third element as ring gear

[0109] 3-PT third element as planetary gear carrier

[0110] 1-SRA first element as first sun gear

[0111] 2-SRB second element as second sun gear

[0112] 1-HRA first element as first ring gear

[0113] 2-HRB first element as second ring gear

Claims

Patent claims 1. Bottom bracket gear in planetary design for a bicycle or a pedelec (1), with a pedal crankshaft (WAn) as input and a transmission output shaft (WAb) as output and with further shafts (W1, W2, W3, W4, W5) as well as with a first transmission shifting group (3) and a second transmission shifting group (4), which are coupled to one another to realize several gears (G1, G2, G3, G4, G5, G6, G7), wherein the first transmission shifting group (3) comprises a two-stage stepped planetary gear set (StRS) and the second transmission shifting group (4) comprises a planetary gear set (RS), to which a first shifting element (B1), a second shifting element (B2), a third shifting element (B3, B3 1 , B3"), a fourth switching element (K1) and a fifth switching element (K2, K2 1, K2"), wherein the pedal crankshaft (WAn) is connected to a first sun gear (SR1.1) of the stepped planetary gear set (StRS) and the transmission output shaft (WAb) is connected to a third element of the planetary gear set (RS) or via the third shift element (B3 1 ) in a second arrangement variant of the third switching element (B3 1) or wherein the pedal crankshaft (WAn) is connected to the third element of the planetary gear set (RS) and the transmission output shaft (WAb) is connected to the first sun gear (SR1.1) of the stepped planetary gear set (StRS), wherein a first ring gear (HR1.1) of the stepped planetary gear set (StRS) is fixable to a housing (2) via the first shifting element (B1), wherein a second ring gear (HR1.2) of the stepped planetary gear set (StRS) is fixable to the housing (2) via the second shifting element (B2), wherein a stepped planetary gear carrier (SPT) of the stepped planetary gear set (StRS) is connected to a second element of the planetary gear set (RS) or is connectable via the third shifting element (B3") in a third arrangement variant of the third shifting element (B3"), wherein a second sun gear (SR1 .2) of the stepped planetary gear set (StRS) can be connected to the transmission output shaft (WAb) or to the pedal crankshaft (WAn) via the fourth shifting element (K1), and wherein a first element of the planetary gear set (RS) is fixed to the housing (2) or can be fixed to the housing (2) via the third shifting element (B3) in a first arrangement variant of the third shifting element (B3).

2. Bottom bracket transmission according to claim 1, characterized in that the pedal crankshaft (WAn) is connected to the first sun gear (SR1.1) of the stepped planetary gear set (StRS) is connected, that the transmission output shaft (WAb) is connected to a third element of the planetary gear set (RS), that the first ring gear (HR1.1) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a first shaft (W1) when the first shifting element (B1) is locked, that the second ring gear (HR1.2) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a second shaft (W2) when the second shifting element (B2) is closed, that the stepped planetary gear carrier (SPT) of the stepped planetary gear set (StRS) is connected to the second element of the planetary gear set (RS) via a fourth shaft (W4), that the second sun gear (SR1 .2) of the stepped planetary gear set (StRS) is connectable to the transmission output shaft (WAb) via a fifth shaft (W5) when the fourth shifting element (K1) is closed, that the first element of the planetary gear set (RS) is fixable to the housing (2) via a third shaft (W3) when the third shifting element (B3) is closed in the first arrangement variant of the third shifting element (B3), and that in order to block the planetary gear set (RS) in a first blocking variant, the first element of the planetary gear set (RS) is connectable to the third element of the planetary gear set (RS) when the fifth shifting element (K2) is locked in a first arrangement variant of the fifth shifting element (K2). (Figure 1).

3. Bottom bracket transmission according to claim 1, characterized in that the pedal crankshaft (WAn) is connected to the third element of the planetary gear set (RS), that the transmission output shaft (WAb) is connected to the first sun gear (SR1.1) of the stepped planetary gear set (StRS), that the first ring gear (HR1.1) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a first shaft (W1) when the first shifting element (B1) is locked, that the second ring gear (HR1.2) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a second shaft (W2) when the second shifting element (B2) is closed, that the stepped planetary gear carrier (SPT) of the stepped planetary gear set (StRS) is connected to the second element of the planetary gear set (RS) via a fourth shaft (W4), that the second sun gear (SR1.2) of the stepped planetary gear set (StRS) is connectable to the pedal crankshaft (WAn) via a fifth shaft (W5) when the fourth shifting element (K1) is closed, that the first element of the planetary gear set (RS) is connectable to the pedal crankshaft (WAn) via a third shaft (W3) when the third shifting element (B3) is closed. the first arrangement variant of the third shifting element (B3) can be fixed to the housing (2), and that for blocking the planetary gear set (RS) in a first blocking variant, the first element of the planetary gear set (RS) can be connected to the third element of the planetary gear set (RS) when the fifth shifting element (K2) is locked in a first arrangement variant of the fifth shifting element (K2). (Figure 7) 4. Bottom bracket transmission according to claim 1, characterized in that the pedal crankshaft (WAn) is connected to the first sun gear (SR1.1) of the stepped planetary gear set (StRS), that the transmission output shaft (WAb) is connected to a third element of the planetary gear set (RS), that the first ring gear (HR1.1) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a first shaft (W1) when the first shifting element (B1) is locked, that the second ring gear (HR1.2) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a second shaft (W2) when the second shifting element (B2) is closed, that the stepped planetary gear carrier (SPT) of the stepped planetary gear set (StRS) is connected to the second element of the planetary gear set (RS) via a fourth shaft (W4), that the second sun gear (SR1.2) of the stepped planetary gear set (StRS) can be connected to the transmission output shaft (WAb) via a fifth shaft (W5) when the fourth shifting element (K1) is closed, that the first element of the planetary gear set (RS) can be fixed to the housing (2) via a third shaft (W3) when the third shifting element (B3) is closed in the first arrangement variant of the third shifting element (B3), and that in order to block the planetary gear set (RS) in a second blocking variant, the first element of the planetary gear set (RS) can be locked when the fifth shifting element (K2. 1 ) in a second arrangement variant of the fifth shift element (K2) is connectable to the second element of the planetary gear set (RS). (Figure 2) 5. Bottom bracket transmission according to claim 1, characterized in that the pedal crankshaft (WAn) is connected to the first sun gear (SR1.1) of the stepped planetary gear set (StRS), that the transmission output shaft (WAb) is connected to a third element of the planetary gear set (RS), that the first ring gear (HR1.1) of the stepped planetary gear set (StRS) is connected via a first shaft (W1) when the first switching element (B1) can be fixed to the housing (2), that the second ring gear (HR1.2) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a second shaft (W2) when the second switching element (B2) is closed, that the stepped planetary gear carrier (SPT) of the stepped planetary gear set (StRS) is connected to the second element of the planetary gear set (RS) via a fourth shaft (W4), that the second sun gear (SR1.2) of the stepped planetary gear set (StRS) is connectable to the transmission output shaft (WAb) via a fifth shaft (W5) when the fourth shifting element (K1) is closed, that the first element of the planetary gear set (RS) is fixable to the housing (2) via a third shaft (W3) when the third shifting element (B3) is closed in the first arrangement variant of the third shifting element (B3), and that in order to block the planetary gear set (RS) in a third blocking variant, the third element of the planetary gear set (RS) is connectable to the second element of the planetary gear set (RS) when the fifth shifting element (K2) is locked in a third arrangement variant of the fifth shifting element (K2). (Figure 3).

6. Bottom bracket transmission according to claim 1, characterized in that the pedal crankshaft (WAn) is connected to the first sun gear (SR1.1) of the stepped planetary gear set (StRS), that the transmission output shaft (WAb) when the third switching element (B3) is closed 1) in the second arrangement variant of the third switching element (B3 1) can be connected to the third element of the planetary gear set (RS) via a third shaft (W3), that the first ring gear (HR1.1) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a first shaft (W1) when the first shifting element (B1) is locked, that the second ring gear (HR1.2) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a second shaft (W2) when the second shifting element (B2) is closed, that the stepped planetary gear carrier (SPT) of the stepped planetary gear set (StRS) is connected to the second element of the planetary gear set (RS) via a fourth shaft (W4), that the second sun gear (SR1.2) of the stepped planetary gear set (StRS) is connectable to the transmission output shaft (WAb) via a fifth shaft (W5) when the fourth shift element (K1) is closed, that the first element of the planetary gear set (RS) is fixed to the housing (2) via a fixed housing connection (WO), and that when the fifth shift element (K2") is locked in the third arrangement variant of the fifth. Switching element (K2 11 ) the transmission output shaft (WAb) can be connected to the fourth shaft (W4). (Figure 5) 7. Bottom bracket transmission according to claim 1, characterized in that the pedal crankshaft (WAn) is connected to the first sun gear (SR1.1) of the stepped planetary gear set (StRS), that the transmission output shaft (WAb) is connected to the third element of the planetary gear set (RS), that the first ring gear (HR1.1) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a first shaft (W1) when the first shifting element (B1) is locked, that the second ring gear (HR1.2) of the stepped planetary gear set (StRS) can be fixed to the housing (2) via a second shaft (W2) when the second shifting element (B2) is closed, that the stepped planetary gear carrier (SPT) of the stepped planetary gear set (StRS) can be connected to the second element of the planetary gear set via a fourth shaft (W4) when the third shifting element (B3") is closed in the third arrangement variant of the third shifting element (B3") (RS) is connectable so that the second sun gear (SR1.2) of the stepped planetary gear set (StRS) is connectable to the transmission output shaft (WAb) via a fifth shaft (W5) when the fourth shifting element (K1) is closed, that the first element of the planetary gear set (RS) is fixed to the housing (2) via a fixed housing connection (WO), and that when the fifth shifting element (K2") is locked, in the third arrangement variant of the fifth shifting element (K2") the transmission output shaft (WAb) is connectable to the fourth shaft (W4). (Figure 6).

8. Bottom bracket transmission according to one of the preceding claims, characterized in that the first switching element (B1) is designed as a freewheel brake or freewheel, that the second switching element (B2) and the third switching element (B3, B3 1 , B3") are each designed as a positive-locking brake, that the fourth switching element (K1) is designed as a positive-locking clutch, and / or that the fifth switching element (K2, K2 1 , K2") is designed as a freewheel.

9. Bottom bracket gear according to one of the preceding claims, characterized in that the planetary gear set (RS) is designed as a minus planetary gear set.

10. Bottom bracket transmission according to claim 9, characterized in that in a minus planetary gear set the first element is designed as a sun gear (SR), the second element as a planet gear carrier (PT) and the third element as a ring gear (HR).

11. Bottom bracket gear according to one of the preceding claims, characterized in that the planetary gear set (RS) is designed as a plus planetary gear set.

12. Bottom bracket transmission according to claim 11, characterized in that in a plus planetary gear set the first element is designed as a sun gear (SR), the second element as a ring gear (HR) and the third element as a planet gear carrier (PT).

13. Bottom bracket transmission according to one of the preceding claims, characterized in that a torque sensor (5) is connected to the pedal crankshaft (WAn).

14. Bottom bracket transmission according to one of the preceding claims, characterized in that at least one electric machine (EM) is connected or connectable to the pedal crankshaft (WAn) or to the transmission output shaft (WAb).

15. Bottom bracket transmission according to claim 14, characterized in that the electric machine (EM) is arranged axially parallel to the pedal crankshaft (WAn).

16. Bottom bracket transmission according to one of the preceding claims, characterized in that, to realize a first gear (G1), the first switching element (B1) designed as a freewheel brake and the fifth switching element (K2, K2 1, K2"), so that to realize a second gear (G2) the second switching element (B2) designed as a brake is closed and the fifth switching element designed as a freewheel (K2, K2 1 , K2"), that in order to realize a third gear (G3) the first switching element (B1) designed as a freewheel brake is locked and the third switching element designed as a brake (B3, B3 1 , B3") is closed, that in order to realize a fourth gear (G4) the second switching element (B2) designed as a brake and the third switching element (B3, B3 1 , B3") are closed, that to realize a fifth Gear (G5) the fourth switching element (K1) designed as a clutch is closed and the fifth switching element designed as a freewheel (K2, K2 1 , K2") blocks the third switching element (B3, B3) designed as a brake in order to realize a sixth gear (G6). 1, B3") and the fourth switching element (K1) designed as a clutch are closed, and / or that in order to realize a seventh gear (G7) the second switching element (B2) designed as a brake and the fourth switching element (K1) designed as a clutch are closed.

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

Images