Limited slip differential

Claim 1

A limited slip differential comprising: a differential case; a plurality of pinions comprising straight bevel gears and disposed in the differential case, each pinion having a plurality of teeth, each of which includes a first surface and a second surface; a pair of side gears comprising straight bevel gears meshing with the pinions and disposed in the differential case, each side gear having a plurality of teeth, each of which includes a third surface and a fourth surface; and frictional force generating means which limits a differential motion produced between shafts coupled respectively with the side gears, the generating means including a plurality of frictional plates, wherein a pressure angle of the first surface of each pinion tooth is formed larger than a pressure angle of the second surface thereof, pressure angles of the third and fourth surfaces of each side gear tooth being respectively formed equal to the pressure angles of said first and second surfaces of each pinion tooth, said pair of side gears being arranged at first and second sides of said pinions such that the first surface of each pinion tooth is contacted with third surfaces of the side gear teeth of the side gear at said first side while the second surface of each pinion tooth is contacted with fourth surfaces of the side gear teeth of the side gear at said second side when said pinions and side gears are rotated in one direction by said differential case, and said frictional force generating means being arranged such that the number of the frictional plates disposed respectively in a first position between the side gear at said first side and the differential case is different from the number of the frictional plates disposed respectively in a second position between the side gear at said second side and the differential case.