A spindle motor includes a base plate on which a through hole is formed, a stator assembly provided at an top side of the base plate having a stator core with stator windings, a circuit board provided at the bottom side of the base plate and to which a lead wire of the stator windings drawn from the through hole to the bottom side is connected. An insulating cover sheet is provided at the top side of the base plate for covering the through hole, the insulating cover sheet being passed through by the lead wire, and a sealing material filling the through hole. The insulating cover sheet has a wire hole and an air vent part communicating with the through hole, wherein the air vent part faces at least a portion of an inside opening of the through hole. The wire hole and the air vent part are separated from each other or are connected to form a single opening.

An oil-impregnated sintered bearing (8) includes a copper-iron-based sintered compact containing 40 mass % or more of copper, and has inner pores impregnated with an oil. The sintered compact has: a copper structure derived from copper powder (13) of partially diffusion-alloyed powder (11) in which copper powder (13) having a particle diameter of 20 m or less is diffused on and joined to a surface of iron powder (12) in advance; and a copper structure derived from elemental copper powder (14).

A spindle motor includes a base plate in which a through hole is formed, a stator core that is provided inside the base plate and is wound with a coil, and a circuit board that is provided outside the base plate and to which a conducting wire of the coil drawn out to outside through the through hole is connected, wherein the through hole includes an inner opening that opens inward of the base plate, an outer opening that opens outward of the base plate, and an intermediate portion having a cylindrical shape that is provided between the inner opening and the outer opening, an enlarged opening is formed to be connected to the outer opening, the enlarged opening is offset to extend toward a side where the circuit board is not present, and the through hole is sealed with a sealing material.

A spindle motor according to an embodiment includes a base plate, a rotor magnet fixed to a rotor assembly positioned at one surface side of the base plate and a magnetic attraction plate fixed at the one surface side of the base plate so as to face the rotor magnet. An opposite area of the base plate facing the magnetic attraction plate includes a coated area covered by an epoxy electric discharge coating film, and the magnetic attraction plate is fixed to the opposite area via at least one of an epoxy adhesive and an acrylic adhesive.

A spindle motor includes a base plate on which a through hole is formed, a stator assembly provided at an top side of the base plate having a stator core with stator windings, a circuit board provided at the bottom side of the base plate and to which a lead wire of the stator windings drawn from the through hole to the bottom side is connected. An insulating cover sheet is provided at the top side of the base plate for covering the through hole, the insulating cover sheet being passed through by the lead wire, and a sealing material filling the through hole. The insulating cover sheet has a wire hole and an air vent part communicating with the through hole, wherein the air vent part faces at least a portion of an inside opening of the through hole. The wire hole and the air vent part are separated from each other or are connected to form a single opening.

A hollow shaft includes a hollow portion extending in an axial direction from an opening that is open at one end of the hollow shaft in the axial direction. The hollow shaft further includes a first communicating hole establishing radial communication between the hollow portion and an axial space between an upper lubricating oil and a lower lubricating oil. The hollow shaft further includes a second communicating hole establishing radial communication between the hollow portion and an unsealed space inside the motor. The unsealed space is connected to an external space outside the motor. The hollow shaft further includes a sealing member closing the opening. The hollow shaft has, in an inner peripheral surface facing the hollow portion, a recess recessed radially outward. A part of the sealing member is fitted into the recess.

A fluid dynamic bearing device includes a shaft disposed along a center axis, a sleeve cylindrically extending around the shaft, a thruster that closes a lower end of the sleeve, dynamic pressure grooves in the shaft or the sleeve, and a lubricating oil present therebetween. The shaft includes a shaft main body and a shaft flange extending radially outward from a lower end of the shaft main body. An inner peripheral surface of the sleeve includes a first inner peripheral surface that faces an outer peripheral surface of the shaft main body in the radial direction and a second inner peripheral surface that faces an outer peripheral surface of the shaft flange in the radial direction. The sleeve includes a sleeve inner lower surface and a circulation hole.

A spindle motor includes a base plate in which a through hole is formed, a stator core that is provided inside the base plate and is wound with a coil, and a circuit board that is provided outside the base plate and to which a conducting wire of the coil drawn out to outside through the through hole is connected, wherein the through hole includes an inner opening that opens inward of the base plate, an outer opening that opens outward of the base plate, and an intermediate portion having a cylindrical shape that is provided between the inner opening and the outer opening, an enlarged opening is formed to be connected to the outer opening, the enlarged opening is offset to extend toward a side where the circuit board is not present, and the through hole is sealed with a sealing material.

A rotating portion includes a hollow shaft extending along a central axis. The hollow shaft includes a through hole passing therethrough in an axial direction. The rotating portion includes an upper screw to close an upper opening that is an opening at an upper end portion of the through hole. The rotating portion includes a lower screw to close a lower opening that is an opening at a lower end portion of the through hole. The hollow shaft includes an upper groove portion into which the upper screw is screwed at the upper opening. The hollow shaft includes a lower groove portion into which the lower screw is screwed at the lower opening. A lubricating oil is in contact with the lower screw. The lower groove portion is shorter in axial length than the upper groove portion, and the lower screw is smaller in axial pitch than the upper screw.

A fluid dynamic bearing device includes a shaft disposed along a center axis, a sleeve cylindrically extending around the shaft, a thruster that closes a lower end of the sleeve, dynamic pressure grooves in the shaft or the sleeve, and a lubricating oil present therebetween. The shaft includes a shaft main body and a shaft flange extending radially outward from a lower end of the shaft main body. An inner peripheral surface of the sleeve includes a first inner peripheral surface that faces an outer peripheral surface of the shaft main body in the radial direction and a second inner peripheral surface that faces an outer peripheral surface of the shaft flange in the radial direction. The sleeve includes a sleeve inner lower surface and a circulation hole.