Patent ID: 6394926
Filing Date: 2002-05-28
Classification: F16H,Y10S,Y10T

Abstract:
A hydraulic control system for an automatic transmission, comprising:a shift controller having a manual valve cooperating with a driver-controlled select lever to supply hydraulic pressure through range lines; a hydraulic pressure controller including first, second and third pressure control valves which are controlled by reducing pressure controlled by first, second and third solenoid valves, the first, second and third pressure control valves controlling hydraulic pressure supplied from the manual valve a line pressure controller including a line pressure control switch valve and a fourth solenoid valve for controlling the switch valve, the switch valve selectively supplying hydraulic pressure from the first pressure control valve and drive D range pressure from the manual valve to a first clutch and a pressure regulating valve; and a pressure distributor comprising: a low control valve for forming a hydraulic pressure line in a low L range such that control pressure of the third pressure control valve is supplied to the first brake; an N-R control valve for controlling reverse pressure supplied to the first brake using control pressure from the second pressure control valve in a reverse R range; a first fail-safe valve controlled by control pressure supplied from the low control valve and from the second pressure control valve, the first fail-safe valve undergoing port conversion to supply hydraulic pressure supplied from the third pressure control valve to a second clutch in the third and fourth speeds of the drive D range, and hydraulic pressure supplied from the third pressure control valve to a second brake in the low L range; a second fail-safe valve for supplying hydraulic pressure supplied from the second pressure control valve; and an engine brake control switch valve for supplying D-range pressure to a fourth clutch in the first and third speeds of the drive D range.