HYDRAULIC CONTROL SYSTEM OF CONTINUOUSLY VARIABLE TRANSMISSION

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic control system of a continuously variable transmission, capable of suitably suppressing excessive increase in line pressure at the time of failure due to excessive sheave pressure.

SOLUTION: The hydraulic control device for the continuously variable transmission is provided with a first sheave pressure regulating valve 17 for regulating the line pressure Pl as control initial pressure and generating first sheave pressure Pin and with a fail-safe valve 19 for selecting either the first sheave pressure Pin or fail-safe hydraulic pressure (second sheave pressure Pout) applied to a drive pulley 21 at the time of excessive failure of the first sheave pressure Pin and outputting the either sheave pressure to the drive pulley 21. A first regulator valve 12 and a second regulator valve 13 for regulating the line pressure Pl are constituted to adjust the line pressure Pl by performing feedback of output pressure Psf of the fail-safe valve 19 as hydraulic pressure on the drive pulley 21 side.

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