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:
Dec. 17, 1991
Filed:
Sep. 10, 1990
Masaaki Hama, Osaka, JP;
Junichirou Inoue, Osaka, JP;
Kubota Corporation, Osaka, JP;
Abstract
A hydraulically operable transmission comprises change speed gears, a hydraulic clutch, and a hydraulic circuit for operating the change speed gears and hydraulic clutch. The hydraulic circuit includes a plurality of hydraulic actuators interlocked with the change speed gears, and a pilot type control valve for controlling the hydraulic actuators. An oil line leading to the hydraulic clutch includes a pressure increase adjustor for adjusting pressure increase characteristics when the hydraulic clutch is engaged. The pressure increase adjustor includes, arranged parallel to one another, a normally open first switch valve closable when a secondary hydraulic pressure exceeds a first set level, a normally closed second switch valve openable when the secondary hydraulic pressure exceeds a second set level higher than the first set level, and a restrictor. The first switch valve is urged toward an open position by a spring whose urging force is increased when the control valve is operated to a high speed range.