Rotor shaft and method of manufacturing the same

A method of manufacturing a rotor shaft including a rotor that includes a rotor core constituted by laminated steel sheets in a hollow cylindrical shape and an end plate disposed on an end face of the rotor core, and a shaft having a groove formed on a periphery to open radially outwardly, the rotor being fixed to the shaft through a fixing member disposed in a predetermined place in contact with the periphery of the shaft including the groove and adjacent the rotor in an axial direction thereof,

• wherein the method comprises the step of:
• caulking the fixing member to fix the rotor to the shaft by applying a load to an end portion of the fixing member from outside in a radial direction, opposite the groove, when the fixing member is disposed in the predetermined place, causing a part of the fixing member to be press-fitted into the groove,
• the caulking and fixing step including fixing the rotor to the shaft by caulking under a condition of Δc=T−Δt, assuming that a clearance quantity between a caulking jig and the shaft is a punch-shaft clearance quantity Δc, the caulking jig being adapted to move up and down in the axial direction of the rotor to apply a load to the end portion of the fixing member from outside in the radial direction, opposite the groove, the thickness of the portion of the fixing member to which portion the radial load is applied by the caulking jig is a fixing member thickness T, and the depth in the groove in which depth a part of the fixing member is received is a groove bite-in depth Δt, wherein the fixing member has a tapered portion on an outer periphery thereof opposite the groove before applying the load, the tapered portion being formed so that an intersecting point between an extension line of the tapered portion and the outer periphery of the shaft lies on an outside diameter of the shaft and within the area of the groove.