Patent ID: 6390230
Filing Date: 2002-05-21
Classification: B21K,B62D,F16H,Y10T

Abstract:
An electric power steering apparatus comprising:a motor for producing an assist torque in accordance with a steering torque; a rack and pinion mechanism for a steering system, said rack and pinion mechanism having a rack and a pinion; and a geared reduction mechanism for transferring the assist torque to said rack and pinion mechanism, wherein said pinion and said rack of said rack and pinion mechanism are both helical gears, said pinion having a helix angle set to be less than a friction angle of said helical gears, one of said helical gears having a tooth profile wherein at least an addendum thereof is a circular arc generally centered on a reference pitch line, and the other of said helical gears having a tooth profile wherein at least a dedendum thereof is a circular arc generally centered on the reference pitch line.