Drive unit

A drive unit comprising:

• a pedal crankshaft to which a pedal stepping force of a rider is applied;
• an electric motor that detects a torque input to the pedal crankshaft and generates a drive force;
• a transmission that changes shift of the drive force of the electric motor and delivers the drive force to the pedal crankshaft;
• and
• a one-way clutch that is provided on a power delivery path from the electric motor to the pedal crankshaft and blocks delivery of a pedal torque, which has been input to the pedal crankshaft, to a side of the electric motor,
• wherein the transmission includes
• a main shaft that supports a plurality of drive gears and
• a counter shaft that supports a plurality of driven gears that engage with the plurality of respective drive gears,
• the transmission selects one torque delivery gear from the plurality of drive gears, delivers the drive force of the electric motor to the counter shaft, and shifts the torque delivery gear without inverting a rotational direction of the drive gear, and
• the one-way clutch is provided coaxially with the counter shaft.