Brake/drive force controlling apparatus for vehicle

A brake/drive force controlling apparatus for a vehicle, the brake/drive force controlling apparatus comprising:

• a drive source mounted in the vehicle;
• a drive force distribution mechanism that distributes drive force of the drive source to left and right driving wheels;
• a brake force application mechanism that applies brake force to the left and right driving wheels independently;
• and
• a control unit that controls the drive force distribution mechanism and the brake force application mechanism according to an operating state of the vehicle, wherein
• the control unit includes a drive force distribution control unit that controls operation of the drive force distribution mechanism according to an operating state of the brake force application mechanism,
• the drive force distribution control unit includes a speed difference estimation control unit that compares speed of each of the left and right driving wheels with a first equivalent value of wheel speed in a position of each of the left and right driving wheels obtained from vehicle speed, and estimates that the left and right driving wheels are slipping when the speed of each driving wheel is not within a predetermined range of the first equivalent value of the wheel speed, and
• in a case where it is determined that the driving wheels are slipping, the speed difference estimation control unit further estimates that a speed difference between the left and right driving wheels exceeds a preset reference speed difference, when an absolute value of a deviation between a second equivalent value and a third equivalent value is greater than a determination threshold value, the second equivalent value being obtained using wheel cylinder pressure of the left driving wheel and a coefficient of friction of a road surface of the left driving wheel, the third equivalent value being obtained using the wheel cylinder pressure of the right driving wheel and the coefficient of friction of the road surface of the right driving wheel, where the coefficient of friction of the road surface of each of the driving wheels is calculated based on the vehicle weight, together with the brake or drive force of each of the driving wheels, and
• when the speed difference estimation control unit estimates that the speed difference between the left and right driving wheels exceeds the reference speed difference, the drive force distribution control unit stops the operation of the drive force distribution mechanism.