Cone drill bit

摘要

A cone drill bit includes legs and attached to them trunnions with cones mounted thereon. A support unit for mounting the cones upon the trunnions includes a strengthened radial thrust ball bearing which transmits a load directed along a cone centerline. Strengthening the ball bearing in order to increase a bit wear resistance is attained by using the balls which diameter is appropriately related to the bit diameter as well as by strengthening a shoulder on the trunnion between the ball and peripheral roller bearings.