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. 14, 1992
Filed:
Oct. 20, 1989
Youzou Majima, Kariya, JP;
Yutaka Suzuki, Nishio, JP;
Eiju Matsunaga, Kariya, JP;
Toshinobu Ishida, Okazaki, JP;
Sigeru Kamiya, Aichi, JP;
Yasumasa Hagiwara, Okazaki, JP;
Masatoshi Kuroyanagi, Kariya, JP;
Nippondenso Co., Ltd., 1-1, Kariya, JP;
Abstract
A variable-damping-force shock absorber includes a piezoelectric actuator for producing a displacement, a hydraulic pressure chamber filled with a working oil and having a volume variable in response to the displacement produced by said piezoelectric actuator, and a plunger slidably disposed in a sleeve and reciprocally movable in response to a change in the volume of said hydraulic pressure chamber. The sleeve and said plunger define therebetween a gap communicating with said hydraulic pressure chamber. A supply passage for supplying a working oil from an external working oil source into said hydraulic pressure chamber extends through the gap. A leakage of the working oil from the hydraulic pressure chamber through the gap can automatically be compensated for by working oil supplied through the supply passage. Since the working oil leaks from and is supplied into the hydraulic pressure chamber through the gap, the leakage and supply of the working oil are kept in equilibrium.