Patent attributes
A sprocket is engageable with a chain having rollers. The sprocket includes a body and a tooth portion. The tooth portion has front and rear surfaces, a drive side surface and a non-drive side surface. The rear and front surfaces face in opposite axial directions. The drive side surface axially connects the front and rear surfaces on a downstream side. The non-drive side surface axially connects the front and rear surfaces on an upstream side. One of the front and rear surfaces has a first chamfered portion, which is formed in a radially outer portion of at least one tooth portion and tapered radially outward in the axial direction. The drive side surface has a first protrusion, which protrudes downstream in the drive rotation direction and is located radially outwardly from a contact position where the drive side surface contacts each of the rollers when the chain is driven.
