The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 21, 2000
Filed:
Oct. 26, 1998
Applicant:
Inventor:
Robert Thomas Foister, Rochester Hills, MI (US);
Assignee:
General Motors Corporation, Detroit, MI (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01F / ;
U.S. Cl.
CPC ...
252 6252 ; 252 / ;
Abstract
Magnetorheological fluids containing carbonyl iron particles with surface hydroxyl groups and high specific surface area in combination with nonpolar vehicles such as polyalphaolefins and glycol esters can be formulated to resist particle separation under high separation force applications. When the nonpolar vehicle having a suitably high molecular weight is used, the fluids may be used at working temperatures of the order of 200.degree. C.