HYDRAULIC CONTROLLER FOR AUTOMATIC SPEED CHANGER ASSOCIATED WITH DIRECT-COUPLED CLUTCH

摘要

PURPOSE:To prevent excessive temperature rise of working liquid effectively by circulating large amount of working fluid to an oil cooler under heavy load operation. CONSTITUTION:The spool 422 of lockup control valve 420 is communicated from above to an oil path 2A through a restrictor while receives the solenoid pressure Ps of oil path 2D provided with a solenoid valve S3 and subjected to the load of spring 426 from underside. A plunger 424 has the open/close function of an oil path 1T communicating between an oil path 1 and the circulation oil path 6C of oil cooler. The oil path 1 is formed in a sleeve 42B fitted in a hole 42A of valve body to form the valve wall of spool valve. The plunger 424 will open the oil path 1T during when line pressure is produced in the oil path 1 to feed the line pressure through a restrictor r0 to the oil path 6C thus to ensure the amount of working oil to be circulated to the oil cooler.