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:
Jan. 03, 1989
Filed:
Jun. 15, 1987
Fumihiro Ushijima, Okazaki, JP;
Kiyohito Murata, Susono, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
A control device for a hyudraulic friction clutch for a motor vehicle, wherein a piston is moved by a pressurized fluid supplied to a pressure chamber, to effect frictional engagement between driving and driven rotary members, and a proximity shut-off valve is disposed in the piston, for permitting the fluid to be discharged from the pressure chamber through a discharge passage when the piston has reached a ready-to-operate position from which the piston is moved to start the frictional engagement. The control device includes a hydraulic pressure source generating a predetermined line pressure, a pressure adjusting device for adjusting the line pressure to a controlled clutch pressure, a clutch control valve for applying the controlled clutch pressure to the pressure chamber to advance the piston for effecting the frictional engagement of the rotary members, and a controller for commanding the pressure adjusting device to adjust the line pressure to a predetermined lower level, when the controller commands the clutch control valve to supply the pressurized fluid to the pressure chamber for moving the piston to the ready-to-operate position. Thus, drag due to partial engagement of the clutch with the piston at the ready-to-operate position is minimized or eliminated.