Patent ID: 7770484
Filing Date: 2010-08-10
Classification: B41J,F16H,Y10S,Y10T

Abstract:
1. A resin double helical gear molded by injecting a resin into a cavity defined by causing a first die to butt a second die, said resin double helical gear comprising: a first gear portion arranged on one side in face width directions from a central portion in the face width directions, said first gear portion being molded by said first die so as to have teeth which are helical in a direction; a second gear portion arranged on the other side in the face width directions from the central portion in the face width directions, said second gear portion being molded by said second die so as to have teeth which are helical in a direction opposite to that of said first gear portion and each of which is connected to a corresponding one of the teeth of said first gear portion to form a chevron-shaped top portion in a butt portion between said first and second gear portions; and a meshing relief portion, formed in said butt portion, for preventing said chevron-shaped top portion or a reverse to said chevron-shaped top portion from contacting a companion gear meshing with said resin double helical gear.