Clutch hydraulic pressure control circuit

A clutch hydraulic pressure control circuit of a twin-clutch transmission having a twin clutch composed of:

• a first hydraulic clutch corresponding to an odd-numbered gear of a transmission;
• and a second hydraulic clutch corresponding to an even-numbered gear of said transmission, and employing a shift pattern where one of said odd-numbered gear and said even-numbered gear is set in neutral mode when the other of said odd-numbered gear and said even-numbered gear is in drive force transmission mode, said circuit comprising:
• a shift valve that is configured to switch a destination to feed hydraulic pressure to either said first hydraulic clutch or said second hydraulic clutch;
• a holding valve configured to actuate switching operation of the shift valve;
• two shift solenoid valves that operate synchronously to actuate said shift valve, said two shift solenoid valves configured to control actuation of a switching operation of the holding valve;
• and
• said holding valve is configured to keep hydraulic pressure fed to said shift valve even when hydraulic pressure supply through one of said two shift solenoid valves is shut off in a state where hydraulic pressure is fed through said two shift solenoid valves to a path between said shift valve and said shift solenoid valves, or when hydraulic pressure supply through one of said two shift solenoid valves is in a state where no hydraulic pressure is fed through said shift solenoid valves.