Hydraulic pressure control device

A hydraulic pressure control device comprising

• a valve portion which adjusts a fluid flowing into or flowing out of a hydraulic pressure chamber, wherein
• a target pressure which is a target value of a hydraulic pressure in the hydraulic pressure chamber is set and a dead zone which is a range of the hydraulic pressure between a first hydraulic pressure which is lower than the target pressure and a second hydraulic pressure which is higher than the target pressure is set, wherein
• a pressure increasing signal or a decreasing signal is outputted to the valve portion to instruct execution of an inflow or an outflow of the fluid with respect to the hydraulic pressure chamber, so that an actual pressure which is an actual value of the hydraulic pressure in the hydraulic pressure chamber approximates the target pressure when the actual pressure is located outside the dead zone and a holding signal is outputted to the valve portion to hold the actual pressure when the actual pressure is located within the dead zone, wherein
• the valve portion is configured to allow a fluctuation of the actual pressure generated upon execution of the inflow or the outflow of the fluid with respect to the hydraulic pressure chamber for a predetermined time period in response to the pressure increasing signal or the decreasing signal which had been inputted immediately before an inputting of the holding signal, even after the holding signal was inputted, and wherein
• the hydraulic pressure control device further comprising:
• a state judging portion which judges whether or not a state of the hydraulic pressure chamber is in a state in which the actual pressure fluctuates even the holding signal has been inputted to the valve portion;
• and
• a control portion which executes a specific control which keeps the actual pressure to a hydraulic pressure within the dead zone when the state judging portion judges that the state of the hydraulic pressure chamber is in a state that the actual pressure fluctuates even the holding signal has been inputted to the valve portion.