Abstract: A spindle motor for rotating a recording medium. A hub having an end wall portion, a cylindrical portion extending from the end wall portion, and a flange extending from the cylindrical portion radially outwardly is formed by forging, drawing or ironing. The recording medium is placed on the flange portion.

Abstract: A spindle motor having a shaft member secured to a fitting member, a rotary member which is rotatable relatively to the shaft member, a rotor magnet fitted to the rotary member in such a manner that the rotor magnet confronts the rotor magnet and a stator, wherein a pair of inner annular grooves are formed in the shaft member, a pair of outer annular grooves are formed in the rotary member and a plurality of ball members are accommodated in ball-accommodating space defined by these annular grooves.

Abstract: A spindle motor includes a bracket, a shaft member fixed to the bracket, a hub member rotatably mounted on the shaft member with a bearing member therebetween, a rotor magnet mounted on the hub member, a stator disposed in opposed relation to the rotor magnet, and a magnetic fluid sealing assembly disposed on on outer side of the bearings. The shaft member has an elastic sealing member which seals a through-hole formed in the shaft.

Abstract: Disclosed is a spindle motor comprising: a housing, a hub member which is rotatable with respect to the housing and to which a recording member is attached, and a bearing arranged between the housing and the hub member and having an outer member which is rotatably attached thereto through the intermediation of a plurality of spherical members, the hub member being fixed to the above-mentioned outer member by press fitting or shrinkage fitting, and the inner periphery of the hub member being equipped with an annular recess in correspondence with a ball lodging grooved formed on the outer member.

Abstract: A spindle motor includes a bracket, a shaft member fixed to the bracket, a hub member rotatably mounted on the shaft member with a bearing member therebetween, a rotor magnet mounted on the hub member, a stator disposed in opposed relation to the rotor magnet, and a magnetic fluid sealing means disposed on an outer side of the bearing means. The shaft member or bracket has a magnetized portion for suppressing a magnetic flux leaking from a magnetic fluid retaining means of the magnetic fluid sealing means.

Abstract: A spindle motor comprising a fixed shaft member, a hub member rotatably supported by the fixed shaft member through bearings, and a magnetic-fluid type sealing mechanism arranged between the fixed shaft member and the hub member. The magnetic-fluid type sealing mechanism has a rotary member mounted on the hub member, a stationary member mounted on the fixed shaft member, and a magnetic fluid holding device for holding a magnetic fluid. The magnetic fluid holding is secured to the annular mounting portion of the stationary member. The magnetic fluid holding device and the annular portion of the rotary member cooperate with each other in holding the magnetic fluid therebetween.

Abstract: A spindle motor having a shaft member secured to a fitting member, a rotary member which is rotatable relatively to the shaft member, a rotor magnet fitted to the rotary member in such a manner that the rotor magnet confronts the rotor magnet and a stator, wherein a pair of inner annular grooves are formed in the shaft member, a pair of outer annular grooves are formed in the rotary member and a plurality of ball members are accommodated in ball-accommodating space defined by these annular grooves.

Abstract: A magnetic fluid seal assembly comprising an annular sealing clearance communicating with an external space, an annular permanent magnet for forming a magnetic field in the sealing clearance, a ferromagnetic fluid retained in the sealing clearance by the magnetic field but rotationally movable in the sealing clearance, and a scattering preventive portion provided axially outwardly of the sealing clearance for preventing the ferromagnetic fluid from scattering to the external space when the ferromagnetic fluid is rotationally moved.

Abstract: A spindle motor used for example to drive magnetic discs comprises a central shaft and a cylindrical member rotatable relative to the central shaft through a pair of bearings. A small annular clearance is formed between the central shaft and the cylindrical member to communicate with an interior space adjoining one of the bearings. A helical groove is provided at the annular clearance and serves to force any fluid, such as grease vapor, into the interior space.

Abstract: A spindle motor comprises a central shaft, a hub rotatable about the shaft and having a central bore which is open at one end, a first bearing fitted in the bore to surround the shaft, a second bearing disposed within the bore to surround the shaft and axially spaced from the first bearing to be positioned closer to the open end of the bore, and an auxiliary bush fitted in the bore to fittingly receive the second bearing. The bush has an inward flange axially interposed between the first and second bearings. The flange provides a first surface in face-to-face contact with an outer race of the first bearing. The flange further provides a second surface parallel to the first surface and in face-to-face contact with an outer race of the second bearing.