Spindle motor

A spindle motor comprising:

• a housing including a through hole with a pair of apertures at both ends thereof, one of the apertures being closed by a thrust plate and the other aperture being open;
• a bearing accommodated in the through hole of the housing;
• a rotating shaft inserted into the bearing, a radial load and a thrust load thereof being respectively supported by the bearing and the thrust plate;
• a displacement restraining structure for restraining movement of the rotating shaft toward the open aperture by engaging the rotation shaft with the bearing;
• a rotating member secured to the rotating shaft;
• and
• a motor generating electromagnetic function for rotating the rotating member;
• wherein a lubricating fluid is provided between the bearing, and the rotating shaft and the thrust plate;
• the through hole of the housing includes a large diameter portion at the thrust plate side and a small diameter portion at the open aperture side, and a stepped portion is formed at a transition portion between the large diameter portion and the small diameter portion;
• and
• at least a portion of the bearing is located at the large diameter portion side of the housing, and engages with the stepped portion of the housing.