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

摘要

A control system for a continuously variable transmission has a line pressure control valve having ports and a spool for controlling the line pressure of oil supplied to a cylinder of a driven pulley to change the line pressure. The line pressure control valve has chambers at opposite sides of the spool. A spring is provided between one end of the spool and a spring retainer. By draining the oil supplied to the end of the spool in accordance with engine operating conditions, the line pressure is controlled. The line pressure is at a maximum value, when the quantity of the draining oil is at a minimum value.