Abstract: A base plate for a spindle motor is provided defining a minimal axial gap with a relatively rotatable magnet. In an example, a surface of the base plate is positioned at 0.1 mm from an adjacent surface of a relatively rotatable magnet. The base plate is comprised of a composite material such that stiffness is improved and acoustic vibration is reduced, while maintaining low power consumption and a fast start-up time. A first material, being a nonmagnetic material is employed adjacent to a motor magnet, and a second material having a preferred stiffness is employed at a greater radial distance from the magnet than the radial distance between a stator and the magnet.

Abstract: Stator and base plate interface alignment is provided for a spindle motor, meeting design specifications such that motor performance is maintained. A portion of a surface of the stator is separated from the base plate. Accurate stator z-height, parallelism and concentricity are provided for use with a low profile disc drive memory system. In an aspect, laminations are formed about a stator and the bottom layer laminations are formed with a smaller diameter than the top layer lamination. The stator bottom layer laminations seat on a flat base plate machined surface, avoiding a base plate corner radius. Precise machining of a small corner interface of the base plate where a stator is typically seated and aligned with the base plate is made unnecessary. Component machining costs, wear and tear to machining systems, and machining process cycle times are reduced.

Abstract: A base plate for a spindle motor is provided defining a minimal axial gap with a relatively rotatable magnet. In an example, a surface of the base plate is positioned at 0.1 mm from an adjacent surface of a relatively rotatable magnet. The base plate is comprised of a composite material such that stiffness is improved and acoustic vibration is reduced, while maintaining low power consumption and a fast start-up time. A first material, being a nonmagnetic material is employed adjacent to a motor magnet, and a second material having a preferred stiffness is employed at a greater radial distance from the magnet than the radial distance between a stator and the magnet.