Patent ID: 7798283

Claim:
A driving device for a power steering, comprising: an input shaft provided with a serration and connected to an input mechanism linked to a steering handle via the serration; an output shaft provided with a serration and connected to an output mechanism linked to a vehicle wheel via the serration; and a torsion bar that connects the input shaft and the output shaft coaxially and restricts relative rotation between the input shaft and the output shaft about an identical central axis, wherein the serration of the input shaft and the serration of the output shaft are formed with a different number of teeth, and a ratio between the numbers of teeth is a decimal, and to specify a relative rotation position of the input shaft and the output shaft relative to the input mechanism and the output mechanism, a tooth on the serration of the input shaft and a tooth on the serration of the output shaft having a relative position deviation angle about an identical central axis which is equal to or smaller than an allowable value are selected as reference teeth.