Steuerungsanordnung für das Uebersetzungsverhältnis eines stufenlosen Getriebes.

摘要

A continuously variable transmission for a vehicle having a drive pulley (36), a driven pulley (37), a belt (34) engaged with both pulleys, and a transmission ratio control valve (100) having a spool (102) for controlling oil supplied and drained to and from a cylinder (38a) of the drive pulley. A check valve (83) is provided in a drain passage (82) for the drain oil. The check valve (83) has a drain port (84c) and a movable spool (84b) for independently closing the drain port (84c). A shift lock device (170) is provided to shift the spool (84b) so as to close the drain port (84c) when the wheels of the vehicle are locked, thereby preventing the belt (34) and pulleys (36,37) from shifting to a larger transmission ratio position.