FRONT-REAR WHEEL DIFFERENTIAL LIMITING DEVICE FOR FOUR-WHEELDRIVE CAR

PROBLEM TO BE SOLVED: To automatically absorb a speed difference between front wheels and rear wheels generated at the time of turning a vehicle, and restrain torsional stress so as to improve the running performance and safety performance of the vehicle by performing differential limiting according to the presence/absence of abrasion produced by pressurizing a multiple disc clutch by the forward and backward movement of a piston. SOLUTION: A metal ball 13 is guided by a guide groove 14 according to the rotation of a screw shaft 6 to be moved in one direction, whereby a piston 14P moves a shaft part 8 forward and backward. A multiple disc clutch 15C is provided with a brake plate 17 coupled to a spline gear 16 formed on the inner peripheral edge of a housing 9 and a brake disc 19 formed on the outer peripheral edge of a spline gear pipe 18 in such a manner as to be brought into contact friction with the brake plate 17 to be moved laterally. When the multiple disc clutch 15C provided on one side is pressurized by the forward movement of the piston 14P, the contact friction is performed to rotate the housing 9, thereby performing differential limiting.