| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power steering device, capable of restricting generation of noise from a ball bearing. SOLUTION: The electric power steering device 1 is provided with a rack shaft 12 to compose a rack-and-pinion type steering gear 8, a rotor 162 of an electric motor 16 coaxially disposed to cover the outer circumference of the rack shaft 12, a ball screw mechanism 18 provided between the rack shaft 12 and the rotor 162 to convert torque of the rotor 162 into drive force in the direction of an axis 12a of the rack shaft 12, and the ball bearing 165 disposed between the housing 10 with a stator 161 of the electric motor 16 and the rotor 16 to support the rotor 162 to be rotatable to the housing 10. A thermal expansion coefficient of an inner ring 166 of the ball bearing 165 is larger than a thermal expansion coefficient of an outer ring 167. COPYRIGHT: (C)2006,JPO&NCIPI |
