| 摘要 |
<p>PROBLEM TO BE SOLVED: To simplify installation of a worm wheel to a pinion shaft, cope with eccentricity, and ensure sufficient whirl-stop in an electrically driven power steering system. SOLUTION: A steering input shaft 3 is connected to a pinion shaft 4 via a torsion bar 5 and a pinion 4a is engaged with a rack of a rack shaft 6 so as to transmit steering force and steering auxiliary force to a wheel side. A torque sensor 7 is provided with a sensor core 7b. The sensor core 7b is fitted across the input shaft and the pinion shaft and moves up an down in a accordance with the rotation amount of each shaft. The steering auxiliary force generated by the electric motor driven upon output signals of the torque sensor is transmitted to the pinion shaft through engagement between worm 12 and worm wheel 11. A serration 25 is formed on either the outer peripheral surface of the pinion shaft or the inner peripheral surface of a boss 11a of the worm wheel, which is fitted with the centering location 26 of the other remaining peripheral surface. As a result, the worm wheel is installed to the pinion shaft.</p> |
