Patent ID: 7635314
Filing Date: 2009-12-22
Classification: F16H

Abstract:
1. A chain transmission comprising: a driving sprocket, at least one driven sprocket, and an endless roller or bushing chain having rollers or bushings of uniform diameter in meshing engagement with said sprockets, in which: each said sprocket has a plurality of teeth, with tooth gaps between successive teeth; the successive teeth of each sprocket have facing front and back tooth surfaces which are continuous with, and connected to each other by, a tooth gap bottom, the front tooth surfaces facing in the direction of sprocket rotation; the tooth form of each sprocket tooth of at least one of said sprockets has a portion at which the distance from the center line of the tooth to the front tooth surface, at a location radially outward from the pitch circle, is larger than or equal to the distance from the center line at the location of the pitch circle to the intersection of the pitch circle and said front tooth surface; the root diameter df of said at least one of said sprockets, defined as the diameter of a circle tangent to the gap bottoms of the sprocket, is less than 250 mm, and if the difference between the diameter Dp of said pitch circle and the diameter d if the difference between the diameter Dp of said pitch circle and the diameter d said chain transmission is incorporated into a timing drive of an automobile engine, including an engine crankshaft and an engine camshaft, wherein the driving sprocket is attached to said engine crankshaft and the driven sprocket is attached to said engine camshaft.