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:
Apr. 17, 2012
Filed:
May. 27, 2009
Masahiro Ashiba, Kanagawa, JP;
Masahiro Ashiba, Kanagawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A hydraulic shock absorber has a cylinder having a hydraulic fluid sealed therein and a piston connected with a piston rod and slidably provided in the cylinder. The piston is provided with a circular main seat portion to form a main valve chamber communicating with an extension passage. Arcuate sub-seat portions are provided in concentric relation to the main seat portion to form sub-valve chambers. A disk valve is seated on the main and sub-seat portions to form clearances between them that always communicate between the main and sub-valve chambers. The disk valve opens upon receiving the pressure in the main and sub-valve chambers. The clearances restrict the flow of hydraulic fluid flowing out through the sub-valve chambers at the beginning of opening of the disk valve to prevent a sharp change in damping force. The concentric arrangement of the main and sub-seat portions facilitates the setting of an initial deflection for the disk valve.