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. 13, 2010
Filed:
Mar. 27, 2006
Takao Nakadate, Yamato, JP;
Takao Nakadate, Yamato, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A controllable damping force hydraulic shock absorber including a pilot type damping valve having a back-pressure chamber for each of an extension stroke and a compression stroke. A piston connected to a piston rod is fitted into a sealed cylinder in which a hydraulic fluid is contained. During an extension stroke of the piston rod, the hydraulic fluid in an upper cylinder chamber flows to a lower cylinder chamber through an extension-side hydraulic fluid passage, an extension-side orifice hydraulic fluid passage, an extension-side back-pressure chamber, an axial hydraulic fluid passage, a radial hydraulic fluid passage, a compression-side back-pressure chamber, an extension-side check valve and a compression-side hydraulic fluid passage. During a compression stroke, the hydraulic fluid in the lower cylinder chamber flows to the upper cylinder chamber through the compression-side hydraulic fluid passage, the compression-side orifice passage, the compression-side back-pressure chamber, the radial hydraulic fluid passage, the axial hydraulic fluid passage, the extension-side back-pressure chamber, the compression-side check valve and the extension-side hydraulic passage. The hydraulic fluid passage for an extension stroke and the hydraulic fluid passage for a compression stroke have some elements in common, thus simplifying the structure of the controllable damping force hydraulic shock absorber.