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:
Oct. 31, 2000
Filed:
Jun. 08, 1998
Yukio Uchida, Kanagawa, JP;
Tetsuya Ishii, Kanagawa, JP;
Atsushi Ishizuka, Kanagawa, JP;
Masateru Yamamuro, Kanagawa, JP;
Unisia Jecs Corporation, Atsugi, JP;
Abstract
A hydraulic pump including a pressure chamber, a drain passage communicable with the pressure chamber, a delivery port, a discharge path fluidly connecting the pressure chamber with the delivery port, and an orifice disposed in the discharge path. A first flow control valve is provided for variably controlling fluid communication between the pressure chamber and the drain passage in response to a difference between fluid pressures upstream and downstream of the orifice. A second flow control valve is disposed within the discharge path, which is operative to variably control an opening area of the orifice in response to energy of fluid passing through the discharge path. The second flow control valve includes a moveable spool exposed to a fluid pressure within the pressure chamber, a spring biasing the spool in such one direction as to increase the opening area of the orifice, and a spring retainer cooperating with the spool to define a spring chamber accommodating the spring.