Steering apparatus

摘要

An electric power steering apparatus 10 has an electric motor 46 for supplying an auxiliary force to a steering force inputted from a steering wheel 16, and transmits the steering force including the auxiliary force to a steered road-wheel 14 at least partially via a rack-and-pinion mechanism 30, thereby performing steering of a vehicle 12. The rack-and-pinion mechanism 30 includes: a pinion 38 provided at a pinion shaft 28 connected to the steering wheel 16; a rack 40 that is provided over a predetermined width at a rack shaft 32 connected to the steered road-wheel 14, and that is engaged with the pinion 38; and a rack guide 70 for urging the rack shaft 32 toward the pinion 38. A pressure angle α1 of a tooth root of the rack 40 is set to be greater than a pressure angle α0 of a tooth tip of the rack 40.