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. 17, 2012
Filed:
Jul. 07, 2008
Takanobu Sato, Iwata, JP;
Seiji Sato, Iwata, JP;
Kouichi Onimaru, Iwata, JP;
NTN Corporation, Osaka, JP;
Abstract
A chain tensioner includes a plunger axially slidable in a cylinder to define a pressure chamber, filled with hydraulic oil, whose volume is variable upon axial plunger movement. A restricted passage defined between the plunger and the cylinder communicates the chamber with outside. A spring biases the plunger to increase the pressure chamber volume. An oil supply passage supplies oil to the pressure chamber and a check valve allows only oil flow into the pressure chamber, and includes an annular valve seat, a check ball movable into and out of contact with the valve seat, and a check ball retainer formed by drawing. The retainer includes a tubular portion with a bottom at one end. The tubular portion has an opening, formed by punching outwardly, through which oil can flow in and out. The opening extends to a border between the tubular portion and the bottom of the retainer.