Patent ID: 6338358
Filing Date: 2002-01-15
Classification: G05D,Y10T

Abstract:
A pressure control apparatus provided with a valve for controlling a secondary pressure in accordance with an action of a pilot pressure supplied by ON/OFF control of an air-supplying solenoid-operated valve and an air-discharging solenoid-operated valve, said pressure control apparatus comprising:said air-supplying solenoid-operated valve for maintaining a valve-closed state when electric power application is stopped; said air-discharging solenoid-operated valve for maintaining a valve-closed state when said electric power application is stopped; a power source drop-detecting mechanism for detecting whether or not a power supply source is dropped to be lower than a predetermined value; a power source-compensating mechanism for delaying drop of a solenoid-operated valve-driving power source for driving said air-discharging solenoid-operated valve when said power supply source is dropped; and a control mechanism for deriving an OFF signal to said air-supplying solenoid-operated valve and deriving an ON signal to said air-discharging solenoid-operated valve on the basis of a power source drop detection signal derived from said power source drop-detecting mechanism.