BICYCLE SPROCKET AND BICYCLE DRIVE TRAIN

• Main Authors: EMURA, Atsuhiro, FUKUMORI, Tsuyoshi, FUKUNAGA, Yasufumi
• Format: Patent
• Language: English
• Published: 28.11.2019
• Subjects: BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVINGPURPOSES; BLASTING; CHAINS; CYCLES; ENGINEERING ELEMENTS AND UNITS; FITTINGS PREDOMINANTLY USED THEREFOR; GEARING; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS; LIGHTING; MECHANICAL ENGINEERING; PERFORMING OPERATIONS; POWERED PROPULSION OF SLEDGES OR; RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; THERMAL INSULATION IN GENERAL; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES; TRANSPORTING; WEAPONS

A bicycle sprocket comprises a sprocket body, a plurality of sprocket teeth, and at least one upshifting facilitation area. The plurality of sprocket teeth extends radially outwardly from the sprocket body with respect to the rotational center axis. The plurality of sprocket teeth includes at least one axially recessed upshifting initiation tooth. The at least one axially recessed upshifting initiation tooth includes a driving surface, a non-driving surface and a tooth tip portion. The non-driving surface includes a non-driving surface protrusion disposed radially inwardly from a non-driving surface side tooth tip end with respect to a rotational center axis. The non-driving surface protrusion has a protrusion tip disposed closer to the second axially-facing surface than the non-driving-surface-side tooth tip end in the axial direction so that a guiding slope extends from the protrusion tip toward the first axially-facing surface.