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

A bottom-bracket transmission with a planetary design for a bicycle or a pedelec (1), comprising:

• a pedal crankshaft (WAn) as a drive;
• a transmission output shaft (WAb) as an output;
• a plurality of shafts (W1, W2, W3, W4, W5, W6, W7);
• and
• a first transmission shifting group (3) and a second transmission shifting group (4) coupled together for implementing a plurality of gears (G1, G2, G3, G4, G5, G6, G7, G8, G9, G10, G11, G12), the first transmission shifting group (3) comprising a two-stage stepped planetary gear set (StRS1) to which three shifting elements (B1, B2, F1I, F1II, F1III, F1IV, F1V, F1VI, F1VII, F1VIII) are assigned,
• wherein a first shaft (W1) of the plurality of shafts as an input shaft of the first stepped planetary gear set (StRS1) is connected to a second ring gear (HR1.2) of the first stepped planetary gear set (StRS1),
• wherein a fifth shaft (W5) of the plurality of shafts as an output shaft of the first stepped planetary gear set (StRS1) is connected to a first ring gear (HR1.1) of the first stepped planetary gear set (StRS1),
• wherein a second sun gear (SR1.2) of the first stepped planetary gear set (StRS1) is fixable to a housing (2) via a first shifting element (B1),
• wherein a first sun gear (SR1.1) of the first stepped planetary gear set (StRS1) is fixable to the housing (2) via a second shifting element (B2),
• wherein a stepped planetary gear carrier (SPT1) of the first stepped planetary gear set (StRS1) is rotatably mounted, and
• wherein, for blocking the stepped planetary gear set (StRS1), two elements of the first stepped planetary gear set (StRS1) are connectable via a fifth shifting element (F1I, F1II, F1III, F1IV, F1V, F1VI, F1VII, F1VIII).