A human-powered vehicle includes a crank axle, a first rotational body, a wheel, a second rotational body, a transmission body that transmits a driving force between the first rotational body and the second rotational body, a derailleur configured to operate the transmission body to change a transmission ratio, an electric actuator configured to actuate the derailleur, and a motor configured to drive the transmission body. A control device has an electronic controller configured to control the motor and drive the transmission body upon determining the derailleur has been actuated with the electric actuator to change the transmission ratio and a predetermined condition related to pedaling is satisfied. The electronic controller is configured to control the electric actuator so as not to change the transmission ratio until a first condition related to shifting is satisfied in a case where the derailleur is actuated.

A control device includes an electronic controller that controls a motor of a human-powered vehicle. The electronic controller outputs a signal to change a transmission ratio by operating a linking body with a derailleur while driving the linking body with the motor where a first condition related to pedaling is satisfied. The first condition relates to at least one of a pedal state, a human driving force input to the pedal, a crank arm state, a human driving force input to the crank arm, a crank axle angular acceleration, a rotational state of a first rotational body, a tire state, a rotational state of a second rotational body, an operational state of the linking body, an operational state of the derailleur, a rotational state of the motor, an electric energy supplied to the motor, a handlebar state, a saddle state, and positional information of the human-powered vehicle.

In a drive unit attached to a vehicle-body frame of an electric-motor-assisted bicycle including a one-way clutch including an outer member, an inner member, a plurality of clutch lugs, a plurality of springs, and a plurality of pins. Clutch teeth are located on one of an inner peripheral portion of the outer member and an outer peripheral portion of the inner member. The clutch lugs and the springs are located on the other of the inner peripheral portion and the outer peripheral portion. A number of the clutch lugs is an even number not smaller than four. A number of the clutch teeth is an even number that is not a multiple of the number of the clutch lugs. A number of the springs is half the number of clutch lugs. Each spring exerts a biasing force on two of the clutch lugs that are circumferentially adjacent. Each pin is in contact with one of the springs.

A torque transmission device includes an input disc, an output disc, an intermediate disc positioned between the input disc and the output disc, a first pair of links coupled by a first side to the input disc and by a second side, opposite to the first side, to the intermediate disc, the links of the first pair being positioned diametrically opposite each other relative to the intermediate central axis, a second pair of links coupled by a first side to the intermediate disc and by a second side, opposite to the first side, to the output disc, the links of the second pair being positioned diametrically opposite each other relative to the intermediate central axis of the intermediate disc, the two pairs of links being aligned in two respective directions perpendicular to each other.

In a drive unit in an electric-motor-assisted bicycle, as viewed in an axial direction of the crank axle, a substrate housed in a housing does not overlap a reduction gear but overlaps a driven gear. The substrate is disposed around the crank axle and includes a component side extending in a direction crossing the central axis of the crank axle. The substrate extends in directions crossing radial directions of the crank axle. One end of the substrate in the direction in which the substrate extends is located on the side of the straight line connecting the shaft center of the crank axle and the shaft center of the motor output shaft as viewed in the axial direction, that is opposite to the side having the other end of the substrate in the direction in which the substrate extends.

An electric-motor-assisted bicycle includes a vehicle-body frame and a drive unit including two couplers. The vehicle-body frame includes a bracket and a pair of chain stays. The drive unit is attached to the bracket. Each of the chain stays is attached to a position on the bracket rearward of a crank axle in the front/rear direction of the bicycle. One coupler is forward of the crank axle in the front/rear direction of the bicycle. The other coupler is rearward of the crank axle in the front/rear direction of the bicycle. At least one of a region of the bracket to which the chain stay is attached and a region of the bracket to which the other coupler is attached does not overlap a line segment connecting a shaft center of the axle of the rear wheel to a shaft center of the crank axle.

An electric-motor-assisted bicycle includes a vehicle-body frame and a drive unit including two couplers. The vehicle-body frame includes a bracket and a pair of chain stays. The drive unit is attached to the bracket. Each of the chain stays is attached to a position on the bracket rearward of a crank axle in the front/rear direction of the bicycle. One coupler is forward of the crank axle in the front/rear direction of the bicycle. The other coupler is rearward of the crank axle in the front/rear direction of the bicycle. At least one of a region of the bracket to which the chain stay is attached and a region of the bracket to which the other coupler is attached does not overlap a line segment connecting a shaft center of the axle of the rear wheel to a shaft center of the crank axle.

In an electric-motor-assisted bicycle, a motor includes a motor output shaft including a helical gear provided thereon. A reduction gear includes a rotatable shaft and a cylindrical portion. The rotatable shaft extends through the cylindrical portion. A helical gear provided on the cylindrical portion engages the helical gear on the motor output shaft. The rotatable shaft includes a first large-diameter portion, a small-diameter portion and a second large-diameter portion. The reduction gear further includes a bush bearing between an end surface of the first large-diameter portion and an end surface of the second large-diameter portion in the axial direction of the rotatable shaft. The outer periphery of the bush bearing is fixed to the cylindrical portion. The inner periphery of the bush bearing slides in a circumferential direction relative to the small-diameter portion. The bush bearing moves in the axial direction.

In an electric-motor-assisted bicycle, a motor includes a motor output shaft including a helical gear provided thereon. A reduction gear includes a rotatable shaft and a cylindrical portion. The rotatable shaft extends through the cylindrical portion. A helical gear provided on the cylindrical portion engages the helical gear on the motor output shaft. The rotatable shaft includes a first large-diameter portion, a small-diameter portion and a second large-diameter portion. The reduction gear further includes a bush bearing between an end surface of the first large-diameter portion and an end surface of the second large-diameter portion in the axial direction of the rotatable shaft. The outer periphery of the bush bearing is fixed to the cylindrical portion. The inner periphery of the bush bearing slides in a circumferential direction relative to the small-diameter portion. The bush bearing moves in the axial direction.

A lightweight, compact electric drive unit provides high reduction ratios for a bicycle, light electric vehicle or autonomous device. A cycloid gear reducer includes one or more cycloid gears within a housing. The cycloid gears interact with gear teeth on the inside surface of the housing, and ride on a cam shaft having eccentric lobes. Output pins extend through apertures in the cycloid gears, from an input carrier to an output carrier. An electric motor powers the cam shaft, while the output carrier powers a drive train.