Driving unit and electric assist bicycle

摘要

A driving unit for use in an electric assist bicycle with reduced size as measured in an axial direction of the crankshaft is provided. A driving unit 50 may be used in an electric assist bicycle 10. The driving unit 50 includes a motor 60, a first transmission gear 84 and a driven gear 104. Out of the motor 60, first transmission gear 84 and driven gear 104, a first component 104 is a component with the largest diameter as viewed in an axial direction of the crankshaft 54, and a second component 60 is a component with the second largest diameter. A substrate 150 is located between the first and second components 104 and 60 as measured in an axial direction of the crankshaft 54.