Chain-rings set, for a power transmission system, which includes a chain, a first chain-ring, a second chain-ring where the first chain-ring is formed by a support part of the teeth and a teeth part, where the second chain-ring is formed by segments each formed by a support part of the teeth and a teeth part, which includes axial displacement means of the segments, where an up-shift segment of the segments has a first tooth which is the first which is engaged with the chain in the rotation movement, and where the displacement means are configured for moving the up-shift segment to an engaging position such that the first tooth can engage with an engaging link of the up-shift section of the chain, when the chain is engaged in the small chain-ring, and without the support part of the up-shift segment reaching the same plane than the support part of the first chain-ring, and to successively displace the other independent segments to an engaging position with the chain without the support parts of the independent segments reaching the same plane than the support part of the first chain-ring.

A harmonic deceleration module, a dynamic power device, an automatic mobile vehicle, a transfer apparatus, a dynamic power supply system, and an electric bicycle are provided. The harmonic deceleration module includes a connecting member, a flexible bearing, a first frame, a first circular spline, a second frame, and a second circular spline. When the connecting member is driven, the connecting member rotates around a central axis. The connecting member has a cam part, and the cam part and the flexible bearing jointly form a wave generator. The wave generator is configured to be driven by the connecting member to drive a flexspline to continually and flexibly deform, and the flexspline drives the second circular spline and the second frame connected to the second circular spline to rotate. The second frame has a hollow channel penetrating through the second frame along the central axis.

A harmonic deceleration module, a dynamic power device, an automatic mobile vehicle, a transfer apparatus, a dynamic power supply system, and an electric bicycle are provided. The harmonic deceleration module includes a connecting member, a flexible bearing, a first frame, a first circular spline, a second frame, and a second circular spline. When the connecting member is driven, the connecting member rotates around a central axis. The connecting member has a cam part, and the cam part and the flexible bearing jointly form a wave generator. The wave generator is configured to be driven by the connecting member to drive a flexspline to continually and flexibly deform, and the flexspline drives the second circular spline and the second frame connected to the second circular spline to rotate. The second frame has a hollow channel penetrating through the second frame along the central axis.

A two-wheeled, variable configuration bicycle having a frame, a handlebar, a saddle, pedals with pedal cranks and a drive gear rotatably mounted on the frame, a front wheel mounted on the front fork, a rear wheel with a sprocket mounted on a rear fork. The bicycle includes the upright configuration and the recumbent configuration, and in recumbent configuration, the bicycle provides support for the back of the cyclist. The frame (2, 2′) are provided two front mounting locations for attaching the front fork (14), wherein the first front mounting location is provided for attaching the front fork (14) in the upright configuration, and the second front mounting location is provided for attaching the front fork (14) in the recumbent configuration. The frame (2, 2′) are provided two rear mounting locations for attaching the rear fork (17).

A two-wheeled, variable configuration bicycle having a frame, a handlebar, a saddle, pedals with pedal cranks and a drive gear rotatably mounted on the frame, a front wheel mounted on the front fork, a rear wheel with a sprocket mounted on a rear fork. The bicycle includes the upright configuration and the recumbent configuration, and in recumbent configuration, the bicycle provides support for the back of the cyclist. The frame (2, 2′) are provided two front mounting locations for attaching the front fork (14), wherein the first front mounting location is provided for attaching the front fork (14) in the upright configuration, and the second front mounting location is provided for attaching the front fork (14) in the recumbent configuration. The frame (2, 2′) are provided two rear mounting locations for attaching the rear fork (17).

A bicycle sprocket comprises a sprocket body, a plurality of sprocket teeth, a mounting member, at least one fastening member, and a cover member. The sprocket body has at least one first threaded portion. The mounting member has at least one fastening hole configured to be aligned with the at least one first threaded portion in the assembled state. The at least one fastening member has a fastening shaft portion, a fastening head portion, and a second threaded portion. The second threaded portion is configured to threadedly engage with the at least one first threaded portion of the sprocket body in the assembled state. The cover member is configured to at least cover the fastening shaft portion of the at least one fastening member when viewed from an axial direction with respect to the rotational center axis in the assembled state.

A bicycle sprocket comprises a sprocket body, a plurality of sprocket teeth, a mounting member, at least one fastening member, and a cover member. The sprocket body has at least one first threaded portion. The mounting member has at least one fastening hole configured to be aligned with the at least one first threaded portion in the assembled state. The at least one fastening member has a fastening shaft portion, a fastening head portion, and a second threaded portion. The second threaded portion is configured to threadedly engage with the at least one first threaded portion of the sprocket body in the assembled state. The cover member is configured to at least cover the fastening shaft portion of the at least one fastening member when viewed from an axial direction with respect to the rotational center axis in the assembled state.

A velocipede includes a pedal crank for pedals to allow an operator to power the velocipede, and a transmission hub or component that is coupled to the pedal crank by a first chain or belt. The transmission component is located rearward of the pedal crank in the frame of the velocipede, such as under a seat position, and is further connected to a rear wheel at an output of the transmission component by a second chain or belt. The transmission has an output that is coupled to a rear wheel assembly. In some embodiments the rear wheel assembly can be mounted in a swingarm that pivots about a transverse axis defined by the output of the transmission. In some embodiments the rear wheel assembly can include an electric motor to drive a rear wheel.

A bicycle chainring may have a plurality of first teeth that fit within the narrow link spaces in a drive chain, and a plurality of second teeth that fit within the wide link spaces in a drive chain. Each second tooth may have a first width that is greater than the its tip width at a location that is between about 40% and about 60% of the tooth height and a second width that is greater than the first width and is between the first plane and the root. A first transition portion may be on a first side of the second tooth and may extends between a first edge that is at the tip and extends in an edge direction that is substantially parallel to the central plane and a second edge that is disposed at the second plane and extends in the edge direction.

A structure of a speed sensor arrangement of a vehicle is provided. The vehicle includes a power unit. The power unit is connected with a transmission system. The transmission system is formed with a sensing space. The sensing space is provided therein with a speed sensor. As such, the speed sensor is arranged in a completely concealed space to prevent the speed sensor from being hit by external sand and stones or corroded by external dust or moisture.