A driving force distribution apparatus for right and left wheels

A hydraulic pump 61 of a driving force distribution apparatus 1 for right and left axles 3, 4 includes a pump shaft 66, a swash plate 67 supported tiltably, swash plate tilting and holding mechanism unit 70 for tilting and holding the swash plate to one side or to the other side depending on the direction of rotation of the pump shaft, and a hydraulic oil supply mechanism unit 80 having a cylinder block 81. The cylinder block holds pistons 82 which reciprocate inside cylinder holes 83 while making contact with a tilt surface of the swash plate at their extremities. When the pump shaft rotates in a forward direction or reverse direction, the pistons reciprocate to supply hydraulic oil sucked from a tank T to a suction port P of an operation control valve 90. Thus, the driving force distribution apparatus can apply relative rotating forces to right and left axles even during backward running, with no increase in the size of the apparatus.