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:
Jul. 06, 1999
Filed:
Apr. 18, 1997
Tamotsu Todo, Kanagawa, JP;
Yasuo Fukuda, Kanagawa, JP;
Noriomi Hosaka, Kanagawa, JP;
Seiji Tsuruta, Kanagawa, JP;
Kenji Suzuki, Kanagawa, JP;
Shin Koizumi, Kanagawa, JP;
Unisia Jecs Corporation, Atsugi, JP;
Abstract
A method of producing a valve lifter to be used in a valve operating mechanism of an automotive vehicle. The valve lifter includes a skirt section, a crown section formed one end of the skirt section so that a cam of a camshaft is slidably contactable with the crown section, and a contacting section formed at an inside surface of the crown section and contactable with a valve stem of an engine valve. The production method comprises the following steps in the sequence set forth: (a) cold-forging a base material to form a valve lifter-shaped base material; (b) cold-pressing the base material to shape the valve lifter-shaped base material; (c) grinding an outer surface of the valve lifter-shaped base material to trim an outer shape of the valve-lifter-shaped base material; (d) totally machining the outer surface and an inner surface of the valve-shaped base material to adjust dimensions of parts of the valve lifter-shaped base material; (e) heat-treating only a part of the valve lifter-shaped base material, corresponding to the contacting section, to increase a hardness of the contacting section; and (f) grinding the contacting section to finish the contacting section.