# US 8,853,908 B2 · Magnet rotor assembly including a vacuum impregnated bonded magnet having increased crush strength at high temperatures > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,853,908 B2 - Document ID: US8853908B2 - Status: Granted - Kind: B2 - Application number: 13/035,979 - Filed: 2011-02-27 - Published: 2011-09-01 - Granted: 2014-10-07 - Earliest claimed: 2010-02-27 - Assignees: MBS Engineering, LLC - Applicants: Stanley Byron Musselman; Edward E Welker; Mitchell L Spencer; Viswanathan Panchanathan - Inventors: Stanley Byron Musselman; Edward E Welker; Mitchell L Spencer; Viswanathan Panchanathan - Web page: https://patentgrep.com/patent/US8853908B2 ## CPC - H02K 15/03: having permanent magnets - H02K 1/2733: Annular magnets - H02K 1/28: Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures - Y10T 29/49012: Rotor - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A magnet rotor assembly comprises a magnet sleeve held on a rotor shaft by a rigid adhesive layer that includes at least one axial wedge shape corresponding to an axial irregularity on at least one of the surfaces bonded by the adhesive layer. Improved crush strength in the magnet sleeve and in other bonded metal parts, both initially and after exposure to high temperatures is accomplished by impregnating the parts with a curable resin. ## Claims ### Claim 1 A bonded powdered metal magnet comprising: a. a bonded powdered metal magnet with pores and of a predetermined shape; and b. an anaerobically cured resin vacuum impregnated into the pores of the bonded powdered metal magnet wherein the resin remains in the pores and provides the bonded powdered metal magnet with improved crush strength at elevated temperatures. ### Claim 2 (depends on 1) The bonded powdered metal magnet of claim 1 wherein the bonded powdered metal magnet has pores and is of a predetermined shape comprises powdered ferrite, samarium-cobalt, neodymium-iron-boron, alnico or mixtures thereof and always includes the bonded powdered metal magnet with pores having a binding resin. ### Claim 3 (depends on 1) The bonded powdered metal magnet of claim 1 wherein the anaerobically cured resin is a methacrylate resin. ### Claim 4 (depends on 1) The bonded powdered metal magnet with pores of claim 1 having a pre-formed shape defining a cylindrical magnet sleeve. ### Claim 5 (depends on 4) A bonded powdered metal magnet with pores of claim 4 further comprising a rotor shaft mounted on the bonded powdered metal magnet wherein the resulting device is a magnet rotor assembly. ### Claim 6 (depends on 5) The magnet rotor assembly of claim 5 additionally comprising a rigid adhesive layer comprising a one-part Bisphenol A epoxy resin/amine hardener system connecting the rotor shaft and the magnet sleeve, the adhesive layer comprising a reduced incidence of curing-induced air bubbles. ### Claim 7 (depends on 6) The magnet rotor assembly of claim 6 wherein at least one of the rotor shaft and the magnet sleeve comprise at least one axial irregularity adapted to define an axial wedge shape in the adhesive layer. ### Claim 8 (depends on 7) The magnet rotor assembly of claim 7 wherein a plurality of such axial irregularities are positioned so as to define a plurality of axial wedge shapes in the adhesive layer, the axial wedge shapes being separated by regions of adhesive having a substantially uniform thickness. ### Claim 9 (depends on 8) The magnet rotor assembly of claim 8 wherein the adhesive layer comprises a one-part aluminum-filled Bisphenol A epoxy resin/amine hardener system and the regions of substantially uniform thickness in the rigid adhesive layer have an average thickness of from about 5 to about 25 microns. ### Claim 10 (depends on 8) The magnet rotor assembly of claim 8 wherein the axial irregularities comprise axial planar regions and wherein the wedge shapes in the adhesive layer are bidirectional. ### Claim 11 (depends on 7) The magnet rotor assembly of claim 7 wherein the magnet sleeve comprises a pre-formed compression bonded magnet, a pre-formed extruded powdered or a pre-formed sintered magnet. ### Claim 12 (depends on 11) The magnet rotor assembly of claim 11 wherein the surfaces of the pre-formed magnet sleeve which are not in contact with the adhesive layer are e-coated. ### Claim 13 (depends on 7) The magnet rotor assembly of claim 7 wherein the rotor shaft comprises at least one magnetically responsive core member mounted on a central shaft. ### Claim 14 (depends on 7) The magnet rotor assembly of claim 7 wherein at least one of the outer circumference of the rotor shaft and the inner circumference of the bonded magnet cylindrical sleeve is roughened.