System for controlling the pressure of oil in a system for a continuously variable transmission

Patent · Tue Jun 27 00:00:00 EDT 1989

OSTI ID:5614938

Satoh, K

This patent describes a control system for a continuously variable transmission for transmitting the power of an internal combustion engine, the transmission comprising a drive pulley having a hydraulically shiftable first disc and a first hydraulic cylinder for shifting the disc, a driven pulley having a hydraulically shiftable second disc and a second hydraulic cylinder for operating the second disc, and a belt engaged with both pulleys, the system comprising a line pressure control valve having a shiftable first spool, a transmission ratio control valve having a shiftable second spool, a first hydraulic circuit having a pump for supplying oil to the first cylinder through the line pressure control valve and transmission ratio control valve, the improvement in the control system which comprises: a second hydraulic circuit for supplying the oil from the pump to the line pressure control valve so as to shift the first spool of the line pressure control valve; a flow rate control valve provided in the second hydraulic circuit for regulating flow rate of oil passing therethrough from an inlet port thereof to an outlet port thereof to a constant value; a reducing valve provided in the second hydraulic circuit and having an inlet communicated with the outlet port of the flow rate control valve so as to produce a constant pressure of oil at an outlet from the reducing valve; control valve means provided in the second hydraulic circuit at a downstream position of the reducing valve communicating with the outlet of the reducing valve for controlling the amount of oil supplied to the first spool of the line pressure control valve so as to shift the first spool of the line pressure control valve to control line pressure in the first hydraulic circuit.

• Assignee: Fuji Jukogyo Kabushiki Kaisha, Tokyo
• Patent Number(s): US 4841814
• OSTI ID: 5614938
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
CONTROL
CONTROL EQUIPMENT
ENGINES
EQUIPMENT
FLOW REGULATORS
FLUID MECHANICS
HEAT ENGINES
HYDRAULIC EQUIPMENT
HYDRAULICS
INTERNAL COMBUSTION ENGINES
LUBRICANTS
LUBRICATING OILS
MACHINE PARTS
MECHANICAL TRANSMISSIONS
MECHANICS
OILS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
PETROLEUM PRODUCTS
PRESSURE CONTROL
VALVES