Abstract: The invention resides in permanent magnet rotors and methods for assembling the same. In one embodiment, one of more arcuate magnetic elements are disposed around a cylindrical rotor core. In turn, a hollow retaining shell is slip-fit around the magnetic element or elements. Spring biasing members are inserted into longitudinal channels defined by grooves in the core and corresponding grooves or chamfers on the one or more magnetic elements. The spring biasing members prevent relative movement between the core, the magnetic element(s), and the retaining shell. Annular end plates are secured to the ends of the core to seal off the interior of the device. In another embodiment, relative movement between the core, magnetic element(s), and retaining shell is prevented by applying adhesive between those parts.

Abstract: A method of preparing corrosion resistant neodymium-boron-iron magnets is provided. The cleaned magnet is coated with zinc phosphate which neutralizes surface effects of contaminants and rinsed with chromic acid. A relatively large surface area having numerous mechanical interlocking sites receptive to adhesives and coatings is obtained. In one embodiment a durable, corrosion-resistant coating such as amide imide or specially formulated zinc-or chromium-rich epoxy primer is applied to the zinc phosphate coated magnet. This can be bonded to a substrate using a suitable adhesive. A flexible epoxy adhesive is used for bonding motor field assemblies.