Walter Scott Blume

US Patent:

6707361, Mar 16, 2004

Filed:

Apr 9, 2002

Appl. No.:

10/118833

Inventors:

Walter Scott Blume - Cincinnati OH

Assignee:

The Electrodyne Company, Inc. - Batavia OH

International Classification:

H01F 4102

US Classification:

335296, 252 6254, 252 6255, 335302, 335303

Abstract:

A flexible permanent magnet containing atomized, generally spherical rare earth magnet particles bonded in a binder resin including a nitrile rubber and precipitated amorphous silica. The bonded permanent magnet exhibits high mechanical flexibility and elasticity, good magnetic properties, and good heat aging, and the magnet powder may be mixed with the binder resin with little to no risk of combustion. In an exemplary embodiment, a permanent magnet composition includes a nitrile rubber with about 23-37% acrylonitrile content, an ethylene vinyl acetate copolymer, a precipitated amorphous silica, and atomized, generally spherical rare earth magnet particles having a size distribution including a median particle size in the range of about 35-55 m with a standard deviation in the range of about 10-30 m and less than about 0. 1% of the particles having a diameter above about 115 m. Bonded permanent magnets of the present invention exhibit a percent ultimate elongation greater than about 100%, and even greater than about 200%, thereby providing at least a 10-fold improvement in elasticity concurrently with good magnetic properties.

US Patent:

48735043, Oct 10, 1989

Filed:

Feb 25, 1987

Appl. No.:

7/018626

Inventors:

Walter S. Blume - Cincinnati OH
Walter S. Blume - Amelia OH

Assignee:

The Electrodyne Company, Inc. - OH

International Classification:

H01F 702

US Classification:

335303

Abstract:

A permanently magnetizable composite is made from rare earth permanent magnet material by incorporating coarse particles of the material into a workable binder at a gradual rate such that sparking and combustion are avoided, until the particles are coated with or embedded in the binder, and then working the mixture under shearing forces sufficient to break up the particles in situ, thereby forming much finer particles directly within the binder. Extremely high particle packing fractions can be obtained in this manner, yet the residual induction of even an isotropic composite substantially exceeds the maximum that would be expected for a magnet having that packing fraction.