Line pressure control system of automatic transmission

A line pressure control system of an automatic transmission comprising:

• a hydraulic pump for generating hydraulic pressure;
• a regulator valve for adjusting the pressure from the hydraulic pump to a predetermined level;
• a torque converter control valve for adjusting a partial pressure from the regulator valve;
• a damper clutch valve receiving the adjusted pressure from the torque converter control valve for feeding the pressure to a damper clutch;
• a damper clutch solenoid valve for controlling the damper clutch valve;
• a reducing valve for reducing a partial pressure from the regulator valve and then supplying the reduced pressure to the damper clutch control valve;
• and
• a manual valve for providing hydraulic pressure to friction elements via hydraulic pressure control means and hydraulic pressure distribution means by driver's manipulation of a manual valve,
• wherein the regulator valve comprises:
• a valve body;
• a first and a second valve spool coaxially inserted into the valve body;
• a sleeve encapsulating the second valve spool;
• a coil spring interposed between the first and the second valve spools,
• wherein the valve body comprises:
• a first port for receiving pressure from the hydraulic pump;
• a second port for returning the pressure from the first port;
• a third port for supplying the pressure from the first port to the torque converter;
• a fourth port communicating with the first port and downstream of the third port;
• a fifth port separated from upstream of the first port for supplying control pressure to the first valve spool;
• a sixth port communicating with a reverse pressure line;
• and
• a seventh port for receiving control pressure from the line pressure control solenoid valve.