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. 06, 2001
Filed:
Dec. 01, 1999
Jeffrey J. Sullivan, Columbus, IN (US);
John D. Crofts, Edinburg, IN (US);
Cummins Inc., Columbus, IN (US);
Abstract
A piezoelectric actuator assembly that is insensitive to wide variations in operating temperatures including a stack of piezoelectric devices and a surrounding housing assembly formed of an outer cylindrical housing portion formed of steel having a coefficient of thermal expansion above that of the piezoelectric material and an inner cylindrical housing portion formed of Si—Ni ceramic. By arranging the inner and outer housing portions in parallel and forming the housing portions with appropriate cross-sectional areas, the housing assembly will have an effective coefficient of thermal expansion &agr;,that is equivalent to that of the piezoelectric element &agr;,. In particular, if the material of the first housing portion has a modulus E,and an effective cross-sectional area A,, and the material of the second housing portion has a modulus E,and an effective cross-sectional area A,, the resultant effective coefficient of thermal expansion will be given by the following formula: