Driving device for an electric bicycle and electric bicycle
In an embodiment a driving device for an electric bicycle includes a motor unit configured to drive the electric bicycle, a drive and a gear stage, wherein the drive is configured to drive the gear stage, wherein the gear stage is configured to drive the electric bicycle, the gear stage being coupled to the drive, on the one hand, and configured to output a torque for driving the electric bicycle, on the other hand, and wherein the gear stage is designed as a strain wave gear and the drive and the strain wave gear are arrangeable coaxially with respect to an axis of rotation of a pedal crank of the electric bicycle.
1 . A driving device for an electric bicycle, the driving device comprising:
a drive; and
a gear stage,
wherein the drive is configured to drive the gear stage,
wherein the gear stage is configured to drive the electric bicycle, the gear stage being coupled to the drive and configured to output a torque for driving the electric bicycle, on the other hand,
wherein the gear stage comprises a strain wave gear,
wherein the drive and the strain wave gear are arrangeable coaxially with respect to an axis of rotation of a pedal crank of the electric bicycle, and
wherein a radial coupling element of the gear stage has, with respect to the axis of rotation, on an outer side a plurality of radial projections arranged in coordination with a plurality of recesses arranged on a transmission element of the gear stage facing the radial coupling element so that the radial coupling element is couplable to and decouplable from the transmission element along the axis of rotation.
2 . The drive device according to claim 1 , wherein the drive is an electric motor comprising a stator and a rotor, each of the stator and the rotor being formed annularly and being arranged such that the stator surrounds the rotor and the rotor is coupled to the gear stage.
3 . The drive device according to claim 2 , wherein, with respect to the axis of rotation, the stator is rotationally fixedly coupled to an outer ring and the rotor is rotationally fixedly coupled to a wave generator.
4 . The drive device according to claim 1 , wherein the gear stage comprises:
a wave generator,
a cylindrical outer ring with internal toothing, and
the transmission element, wherein the transmission element is an elastic transmission element,
wherein the wave generator is configured for predetermined deformation of the transmission element, the outer ring being an input and the radial coupling element being an output of the gear stage, and
wherein the transmission element is arranged between the outer ring and the radial coupling element and is configured to provide a predetermined transmission ratio of the gear stage.
5 . The drive device according to claim 4 , wherein, with respect to the axis of rotation, a stator is rotationally fixedly coupled to the outer ring and a rotor is rotationally fixedly coupled to the wave generator.
6 . The drive device according to claim 4 , wherein the radial coupling element is couplable to the pedal crank.
7 . The drive device according to claim 1 , wherein the radial projections of the radial coupling element, with respect to a state coupled to the transmission element, project along the axis of rotation in a predetermined manner beyond an end face of the transmission element.
8 . The drive device according to claim 1 , wherein, with respect to the axis of rotation, the drive and the gear stage are arranged such that the drive coaxially surrounds the gear stage and the gear stage is able to coaxially surround the pedal crank.
9 . The electric bicycle comprising:
a bicycle frame having a lower frame section extending to a pedal bearing having comprising the pedal crank; and
the drive device according to claim 1 coupled to the bicycle frame such that the drive and the gear stage are arranged coaxially with the pedal crank.
10 . The electric bicycle according to claim 9 , wherein the drive device is arranged as an assembly in an already coupled state to the lower frame section.
11 . A driving device for an electric bicycle, the driving device comprising:
a drive; and
a gear stage,
wherein the drive is configured to drive the gear stage, the gear stage comprising:
a wave generator,
a cylindrical outer ring with internal toothing,
an elastic transmission element having external toothing formed in coordination with the internal toothing of the outer ring, and
a radial coupling element,
wherein the gear stage is a strain wave gear,
wherein the wave generator is configured for predetermined deformation of the transmission element, the outer ring being an input and the radial coupling element being an output of the gear stage,
wherein the transmission element is arranged between the outer ring and the radial coupling element and is configured to provide a predetermined transmission ratio of the gear stage for driving the electric bicycle,
wherein the drive and the strain wave gear are arrangeable coaxially with respect to an axis of rotation of a pedal crank of the electric bicycle, and
wherein the radial coupling element has, with respect to the axis of rotation, on an outer side, a plurality of radial projections arranged in coordination with a plurality of recesses, arranged on the transmission element facing the radial coupling element so that the radial coupling element is couplable to and decouplable from the transmission element along the axis of rotation.
12 . The drive device according to claim 11 , wherein the drive is an electric motor comprising a stator and a rotor, each of the stator and the rotor being formed annularly and being arranged such that the stator surrounds the rotor and the rotor is couplable to the gear stage.
13 . The drive device according to claim 12 , wherein, with respect to the axis of rotation, the stator is rotationally fixedly coupled to an outer ring and the rotor is rotationally fixedly coupled to the wave generator.
14 . The drive device according to claim 11 , wherein, with respect to the axis of rotation, a stator is rotationally fixedly coupled to the outer ring and a rotor is rotationally fixedly coupled to the wave generator.
15 . The drive device according to claim 11 , wherein the radial coupling element is couplable to the pedal crank.
16 . The drive device according to claim 11 , wherein the radial projections of the radial coupling element, with respect to a state coupled to the transmission element, project along the axis of rotation in a predetermined manner beyond an end face of the transmission element.
17 . An electric bicycle comprising:
a bicycle frame having a lower frame section extending to a pedal bearing comprising a pedal crank; and
a drive device comprising:
a drive; and
a gear stage,
wherein the drive is configured to drive the gear stage, the gear stage comprising:
a wave generator,
a cylindrical outer ring with internal toothing,
an elastic transmission element having external toothing formed in coordination with the internal toothing of the outer ring, and
a radial coupling element,
wherein the gear stage is a strain wave gear,
wherein the wave generator is configured for predetermined deformation of the transmission element, the outer ring being an input and the radial coupling element being an output of the gear stage,
wherein the transmission element is arranged between the outer ring and the radial coupling element and is configured to provide a predetermined transmission ratio of the gear stage for driving the electric bicycle,
wherein the drive and the strain wave gear are arranged coaxially with respect to an axis of rotation of the pedal crank, and
wherein the radial coupling element has, with respect to the axis of rotation, on an outer side, a plurality of radial projections arranged in coordination with a plurality of recesses, arranged on the transmission element facing the radial coupling element so that the radial coupling element is couplable to and decouplable from the transmission element along the axis of rotation.
18 . The electric bicycle according to claim 17 , wherein, with respect to the axis of rotation, the drive and the gear stage are arranged such that the drive coaxially surrounds the gear stage and the gear stage coaxially surrounds the pedal crank.
19 . The electric bicycle according to claim 17 , wherein the drive device is arranged as an assembly in an already coupled state to the lower frame section.