Multi-stage transmission structure, power device and electric bicycle

A power device, comprising a multi-stage transmission structure, a motor and a control module that are arranged inside a casing;

• wherein the multi-stage transmission structure comprises:
• a pedal shaft;
• a multi-stage gear group, comprising an input gear group connected with a drive shaft of a motor, an output gear group connected with the pedal shaft, and an intermediate gear group arranged between the input gear group and the output gear group;
• wherein each of the input gear group, the output gear group and the intermediate gear group comprises a gear shaft and at least one gear arranged on the gear shaft;
• the gear shaft of the output gear group is sleeved on an outer side of the pedal shaft;
• a part of the input gear group, the output gear group and the intermediate gear group is provided with two gears spaced apart on the gear shaft along an axial direction of the gear shaft, and a plastic shaft sleeve is sleeved between the two gears and located on the gear shaft;
• and
• a first unidirectional device and a second unidirectional device that are coaxially arranged, the second unidirectional device being connected between the gear shaft of the output gear group and the pedal shaft, the first unidirectional device being arranged between the gear shaft of the output gear group and the at least one gear;
• wherein the first unidirectional device and the second unidirectional device are unidirectional bearings, and the first unidirectional device is an unidirectional wedge bearing;
• wherein a relative rotation direction between the gear shaft and the at least one gear on the output gear group is a first direction, a relative rotation direction between the gear shaft of the output gear group and the pedal shaft is a second direction, and the first direction is opposite to the second direction;
• and
• wherein a torque sensor is arranged on a pedal shaft, and the torque sensor is electrically connected with the control module;
• an angle sensing mechanism is arranged between an interior of the casing and the drive shaft of the motor, and the angle sensing mechanism is electrically connected with the control module.

An electric bicycle, comprising:

• a vehicle body and a power device;
• wherein the power device comprises:
• a multi-stage transmission structure, a motor and a control module that are arranged inside a casing;
• wherein the multi-stage transmission structure comprises:
• a pedal shaft;
• a multi-stage gear group, comprising an input gear group connected with a drive shaft of a motor, an output gear group connected with the pedal shaft, and an intermediate gear group arranged between the input gear group and the output gear group;
• wherein each of the input gear group, the output gear group and the intermediate gear group comprises a gear shaft and at least one gear arranged on the gear shaft;
• the gear shaft of the output gear group is sleeved on an outer side of the pedal shaft;
• a part of the input gear group, the output gear group and the intermediate gear group is provided with two gears spaced apart on the gear shaft along an axial direction of the gear shaft, and a plastic shaft sleeve is sleeved between the two gears and located on the gear shaft;
• and
• a first unidirectional device and a second unidirectional device that are coaxially arranged, the second unidirectional device being connected between the gear shaft of the output gear group and the pedal shaft, the first unidirectional device being arranged between the gear shaft of the output gear group and the at least one gear;
• wherein the first unidirectional device and the second unidirectional device are unidirectional bearings, and the first unidirectional device is an unidirectional wedge bearing;
• wherein a relative rotation direction between the gear shaft and the at least one gear on the output gear group is a first direction, a relative rotation direction between the gear shaft of the output gear group and the pedal shaft is a second direction, and the first direction is opposite to the second direction;
• wherein a torque sensor is arranged on a pedal shaft, and the torque sensor is electrically connected with the control module;
• an angle sensing mechanism is arranged between an interior of the casing and the drive shaft of the motor, and the angle sensing mechanism is electrically connected with the control module;
• and
• wherein a crank of the vehicle body is connected with the pedal shaft in the power device, and a chainset of the vehicle body is fixedly connected with the pedal shaft.