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. 14, 1990
Filed:
Sep. 22, 1988
Yoshiyuki Katayama, Sakai, JP;
Takeshi Ura, Sakai, JP;
Kubota, Ltd., Osaka, JP;
Abstract
A hydraulic control apparatus for a transmission comprising a hydraulic change speed clutch, an oil line connecting the change speed clutch to an oil pump, an electromagnetic proportional reduction valve mounted on the oil line for varying oil pressure output to the change speed clutch in response to control current applied to the reduction valve, a microcomputer for producing the control current and applying the same to the reduction valve, and a command unit for transmitting a command to the microcomputer to engage the change speed clutch. The control current produced by the microcomputer includes a first component current continuing at a first current level for a first predetermined period, a second component current following the first component current and continuing at a second current level lower than the first current level for a second predetermined period, and a third component current following the second component current, starting at a third current level not exceeding the second current level and continuing at a current level which rises with progress of time.