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:
Aug. 31, 2004
Filed:
Sep. 03, 2002
Yoshiyasu Takasaki, Higashimatsuyama, JP;
Hidefumi Inoue, Higashimatsuyama, JP;
Bosch Automotive Systems Corporation, Tokyo, JP;
Abstract
In a negative pressure boosting device, a movable valve seat is air-tightly and slidably disposed in a concavity of a valve body. The movable valve seat and a valve element compose a vacuum valve. A servo ratio changing device includes a control spring compressed and disposed between the movable valve seat and the valve body. The servo ratio changing device is provided on a valve mechanism (the vacuum valve). During operation, the valve element comes in contact with the movable valve seat. The movable valve seat does not move in a low-input range so that the servo ratio is a relatively large ratio for the normal operation. In a high-input range, the control spring starts to be compressed to move the movable valve seat, thereby changing the servo ratio to a small ratio.