Patent ID: 8108116

Claim:
A vehicle brake hydraulic pressure control system, comprising: a hydraulic pressure supply source (M, 18 ) which outputs hydraulic pressure; a hydraulic pressure control unit ( 5 ) which is interposed between the hydraulic pressure supply source (M, 18 ) and wheel brakes (BA, BB) and which adjusts hydraulic pressures at the wheel brakes (BA, BB); a brake hydraulic pressure detecting unit which detects hydraulic pressures at the wheel brakes (BA, BB); and a controller (C) which comprises a target wheel brake pressure setting unit ( 30 ) which sets target hydraulic pressures for the wheel brakes (BA, BB) and which controls an operation of the hydraulic pressure control unit ( 5 ) so that the hydraulic pressures at the wheel brakes (BA, BB) become target hydraulic pressures set by the target wheel brake pressure setting unit ( 30 ), wherein the controller (C) comprises: a target fluid amount calculation unit ( 31 ) which obtains target fluid amounts for the wheel brakes (BA, BB) based on the target hydraulic pressures set by the target wheel brake pressure setting unit ( 30 ); an actual fluid amount calculation unit ( 32 ) which obtains actual fluid amounts for the wheel brakes (BA, BB) based on the hydraulic pressures detected by the brake hydraulic pressure detecting unit ( 23 , 24 ), a target flow rate calculation unit ( 34 ) which obtains target flow rates for the wheel brakes (BA, BB) based on the target fluid amounts obtained by the target fluid amounts calculation unit ( 31 ) and the actual fluid amounts obtained by the actual fluid amount calculation unit ( 32 ), wherein the controller controls the operation of the hydraulic pressure control unit ( 5 ) based on the target flow rates obtained by the target flow rate calculation unit ( 34 ), a pressure build-up timer ( 57 ) which implements counting up normally except when a count value is cleared to “0” where the hydraulic pressure control unit ( 5 ) is controlled to shift from a pressure build-up mode in which the hydraulic pressure of the hydraulic pressure supply source (M, 18 ) is applied to the wheel brakes (BA, BB) to a pressure reducing mode in which the hydraulic pressures are released at the wheel brakes (BA, BB) or a pressure holding mode in which the hydraulic pressures at the wheel brakes (BA, BB) are held; and a pressure reducing timer ( 58 ) which implements counting up normally except when a count value is cleared to “0” when the hydraulic pressure control unit ( 5 ) is controlled to shift from the pressure reducing mode to the pressure build-up mode or the pressure holding mode, and the controller (C) increases a controlled variable of the hydraulic pressure control unit ( 5 ) as a high select value of the count values of the pressure build-up timer ( 57 ) and the pressure reducing timer ( 58 ) increases.