Traction control device for vehicle

A traction control device for a vehicle comprising:

• a master cylinder;
• a vacuum booster having a main control valve for transmitting a pedal force to the master cylinder and an auxiliary control valve for applying a force to the master cylinder in the absence of a pedal force;
• a driven wheel brake connected to the master cylinder via a first fluid passage for being supplied with brake fluid from the master cylinder;
• a non-driven wheel brake connected to the master cylinder via a second fluid passage for being supplied with brake fluid from the master cylinder;
• a driven wheel brake fluid pressure control valve disposed in the first fluid passage for controlling brake fluid pressure in the driven wheel brake by adjusting the amount of brake fluid flowing into and out of the driven wheel brake;
• a non-driven wheel brake fluid pressure control valve disposed in the second fluid passage for controlling brake fluid pressure in the non-driven wheel brake by adjusting the amount of brake fluid flowing into and out of the non-drive wheel brake;
• a fluid pressure pump for sucking brake fluid from the driven wheel brake and the non-driven wheel brake via the driven wheel brake pressure control valve and the non-driven wheel brake fluid pressure control valve respectively, and for discharging brake fluid to an upstream side of the driven wheel brake fluid pressure control valve and an upstream side of the non-driven wheel brake fluid pressure control valve;
• a control unit for controlling brake fluid pressure, the control unit activating the auxiliary control valve for activating the booster according to a slip rate of the driven wheel in the absence of the pedal force, the control unit activating the non-driven wheel brake fluid pressure control valve for interrupting the supply of brake fluid from the master cylinder to the non-driven wheel brake after a predetermined time has lapsed from the activation of the booster so that the non-driven wheel brake initially functions as a brake fluid receiver to prevent an abnormally fast fluid pressure increase in the master cylinder, and thereafter controlling the driven wheel brake fluid pressure control valve for controlling brake fluid pressure in the driven wheel brake by adjusting the amount of brake fluid flowing into and out of the driven wheel brake in accordance with the slip rate of the driven wheel brake while driving the fluid pressure pump.