Vehicle brake hydraulic pressure control device

A vehicle brake hydraulic pressure control device comprising:

• a split road deciding unit configured to decide whether or not a road in contact of wheels of a vehicle is a split road;
• a hydraulic pressure controlling unit capable of executing a limiting processing for limiting a hydraulic pressure of a wheel brake on a high-μ road side so that a differential pressure between a hydraulic pressure of a wheel brake on a low-μ road side and the hydraulic pressure of the wheel brake on the high-μ road side becomes equal to or smaller than an acceptable differential pressure, under condition that the split road deciding unit decides that the road is the split road;
• and
• a vehicle state deciding unit configured to decide whether or not the vehicle is in an unstable state,
• wherein the hydraulic pressure controlling unit is capable of executing:
• a first control for determining the acceptable differential pressure in accordance with a first method during a predetermined time period after the split road deciding unit decides that the road is the split road;
• a second control for determining the acceptable differential pressure in accordance with a second method after the predetermined time period passes;
• and
• a third control configured to be started under condition that during the second control, an anti-lock brake control on the wheel brake on the high-μ road side is started, the acceptable differential pressure is equal to or larger than a first threshold, or a steering angle of a steering is equal to or larger than a second threshold, and
• wherein during the third control, the hydraulic pressure controlling unit is configured to decrease the hydraulic pressure of the wheel brake on the high-μ road side if the vehicle state deciding unit decides that the vehicle is in an unstable state.