Hydraulic control system of shift control unit for dual clutch transmission

A hydraulic control system of a shift control device for a dual clutch transmission, the hydraulic control system comprising:

• a control valve variably controlling a line pressure supplied through a line pressure flow channel to be selectively supplied to a first ejection flow channel and a second ejection flow channel;
• a first shift valve converting a flow channel to supply a hydraulic pressure of the control valve supplied through the first and second ejection flow channels to a lower stream side through two paths, respectively;
• a second shift valve converting a flow channel to selectively supply the hydraulic pressure of the first ejection flow channel supplied from the first shift valve to a first chamber of a first actuator and a first chamber of a second actuator and to selectively supply the hydraulic pressure of the second ejection flow channel supplied from the first shift valve to a second chamber of the first actuator and a second chamber of the second actuator;
• a third shift valve converting a flow channel to selectively supply the hydraulic pressure of the first ejection flow channel supplied from the first shift valve to a lower stream side thereof and a first chamber of a third actuator and to selectively supply the hydraulic pressure of the second ejection flow channel supplied from the first shift valve to a lower stream side thereof and a second chamber of the third actuator;
• and
• a fourth shift valve converting a flow channel to selectively supply the hydraulic pressure of the first ejection flow channel supplied from the third shift valve to a first chamber of a fourth actuator and a first chamber of a fifth actuator and to selectively supply the hydraulic pressure of the second ejection flow channel supplied from the first shift valve to a second chamber of the fourth actuator and a second chamber of the fifth actuator,
• wherein the first, second, third and fourth shift valves are respectively and independently controlled by first, second, third and fourth solenoid valves on/off-controlling the hydraulic pressure supplied from a reducing valve controlling the line pressure into the hydraulic pressure to be further smaller and stable.