| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power steering device generating little noise with a good steering feeling. SOLUTION: The electric power steering device 1 applies power of an electric motor 16 to a steering mechanism A including a rack bar 8 as a steering shaft moved to the axial direction according to operation of a steering member 2 through reduction gears 17 including gears to assist the steering. A piston 20 moves in a hydraulic cylinder 21 along with the movement of the rack bar 8 in the axial direction, and oil flows through a orifice 24 of the piston 20. Comparatively high-speed vibration (15-20 Hz, for example) by reverse input from a road surface is attenuated by damping force composed of viscous resistance of the oil flowing through the orifice 24 to reduce noise of tooth striking sounds. As the movement speed of the piston 20 by normal steering of operating the steering member is low at of 1-2 Hz, for example, the damping force by the orifice 24 hardly works and the steering feeling is not deteriorated. COPYRIGHT: (C)2006,JPO&NCIPI
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