Transmission ratio control system for a continuously variable transmission

Patent · Tue May 30 04:00:00 EDT 1989

OSTI ID:5576718

Tanaka, H

This patent describes a control system for a continuously variable transmission for transmitting power of an internal combustion engine, the transmission having a drive pulley including a hydraulically shiftable first disc and a hydraulic cylinder for operating the disc, a driven pulley including a hydraulically shiftable second disc and a hydraulic cylinder for operating the second disc, and a belt engaged with both pulleys, the control system comprising a hydraulic circuit including a pump for supplying oil to both the hydraulic cylinders, a transmission ratio control valve including a shiftable spool for controlling the oil supplied to the cylinder of the drive pulley to change transmission ratio of the transmission to a desired transmission ratio, shifting means for shifting the spool, sensing means for sensing operating conditions of the engine and the transmission and for producing condition signals dependent on the conditions, actual transmission ratio signal producing means responsive to the condition signals for producing an actual transmission ratio signal corresponding to the actual transmission ratio of the transmission, desired transmision ratio signal producing means responsive to the condition signals for producing a desired transmission ratio signal corresponding to a desired transmission ratio, transmission ratio changing speed signal producing means responsive to the actual transmission ratio signal and to the desired transmission ratio signal for producing a transmission ratio changing rate signal corresponding to a transmission ratio changing rate, and control signal producing means responsive to the transmission ratio changing rate signal for producing a control signal for operating the shifting means to shift the spool dependent on the transmission ratio changing rate for changing the actual transmission ratio of the transmission to the desired transmission ratio.

• Assignee: Fuji Jukogyo Kabushiki Kaisha, Tokyo
• Patent Number(s): US 4833944
• OSTI ID: 5576718
• Country of Publication: United States
• Language: English

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