Apparatus and method for controlling rear wheel braking force of vehicle

In a rear wheel braking force control apparatus of a vehicle comprising proportioning valves (571, 572) disposed in passages (56, 59) for supplying a hydraulic pressure generated by a master cylinder (53) to wheel cylinders (553, 554) of right and left rear wheels for controlling wheel cylinder pressure so that increasing rate of the wheel cylinder pressure is smaller than increasing rate of master cylinder pressure;

• electromagnetic valves (62, 63) disposed in the passage to effect or invalidate the action of said proportioning valves;
• said electromagnetic valves being ON/OFF valves disposed in passages (60, 61) for bypassing said proportioning valves and transmitting the master cylinder pressure to said wheel cylinders;
• and
• control means (71) for controlling operation of said electromagnetic valves;
• said apparatus further comprises:
• braking degree detection means for detecting degree of braking during braking of the vehicle;
• and
• turning condition detection means for detecting turning condition of the vehicle;
• said proportioning valves and said electromagnetic valves being provided for the individual right and left rear wheels;
• said control means operating said electromagnetic valves to invalidate the action of said proportioning valves when the braking degree detected by said braking degree detection means is weaker than a setting degree, and effect the action of said proportioning valves when the braking degree is stronger than the setting degree;
• and
• during turning of the vehicle, the setting degree being corrected so that the setting degree of said electromagnetic valve at the outer wheel side of turning is relatively higher than the setting degree of said electromagnetic valve at the inner wheel side of turning.