HYDRAULISCHES STEUERSYSTEM FÜR EIN STUFENLOSES GETRIEBE

摘要

A hydraulic control system of continuously variable transmission includes: a first sheave pressure regulating valve (17) that regulates a line pressure (Pl), which is used for hydraulic control as a source pressure, to obtain a first sheave pressure (Pin); a fail-safe valve (19) that selects and outputs any one of the first sheave pressure (Pin) or a fail-safe hydraulic pressure (second sheave pressure Pout) that is applied to a drive pulley (21) at the time of a failure due to an excessive first sheave pressure (Pin) to the drive pulley (21); and an orifice (25) that is provided in an oil passage (24) between the fail-safe valve (19) and the drive pulley (21). Then, a hydraulic pressure in the oil passage (24) on the drive pulley (21) side of the orifice (25) is supplied to the first sheave pressure regulating valve (17) as a feedback pressure.