Patent Number: 7,088,024

Title: Field assembly for a motor and method of making same

Abstract: A stator of an electric motor is formed by inserting pre-formed magnets on a cylinder having anchors and plastic is molded around the magnets and anchors to secure the magnets to a surface of the cylinder, forming a cylinder/magnet assembly. A pilot feature is formed in at least one endwall of the plastic molding when it is molded. An end plate is located with respect to the cylinder/magnet assembly by mating a corresponding pilot feature of the end plate with the pilot feature in the endwall of the plastic molding. In another aspect of the invention, magnets are inserted into magnet receiving pockets of a cylinder and plastic molded therearound with the magnet pockets holding the magnets in place during molding of the plastic. In another aspect of the invention, the north and south poles of a cylinder and magnet assembly have unequal distribution angles. In another aspect of the invention, the north and south poles of a cylinder and magnet assembly have unequal numbers of magnets. In another aspect of the invention, the anchors are also formed as flux spreaders. In another aspect of the invention, the stator is used in a power tool.

Inventors: Agnes; Michael (Bel Air, MD), Boyce; Allyn (Baldwin, MD), Du; Hung (Reisterstown, MD), Ortt; Earl (Bel Air, MD), Verbrugge; Brandon (Towson, MD), Walter; Richard H. (Baldwin, MD), Wang; Ren T. (Timonium, MD), Zhang; Jiaqi (Cockeysville, MD)

Assignee: Black & Decker Inc.

International Classification: H02K 21/26 (20060101); H02K 21/38 (20060101); H02K 5/24 (20060101)

Expiration Date: 8/08/02018