Differential gear capable of deriving differential restriction force by frictional resistance with rotations of pinion and side gears

A differential gear for transmitting driving force from an engine to a pair of wheels, comprising:

• a differential case driven by a driving force of an engine, said differential case having an axis;
• a first side gear rotatably received in said differential case along said case axis, said first side gear having means for connecting said side gear to a first wheel;
• a second side gear rotatably received in said differential case along said case axis, said second side gear having means for connecting said second side gear to a second wheel;
• a first pinion gear received in said differential case and having an axis spaced outwardly from said side gears, said first pinion gear having a first gear portion meshed with said first side gear and a second gear portion;
• a second pinion gear received in said differential case and having an axis spaced outwardly from said side gears, said second pinion gear having a first gear portion meshed with said second side gear and a second gear portion meshed with said second gear portion of said first pinion gear;
• said second gear portions of said first and second pinion gears being located outside in the axial direction of said first and second side gears;
• said differential case including a casing body having a cylindrical portion, a flange portion formed outside said cylindrical portion, and a boss portion formed on one end in the axial direction of said cylindrical portion for supporting one of said side gears;
• said cylindrical portion having first and second housing holes for slidably and rotatably receiving therein said first and second pinion gears, respectively;
• said second gear portions having a meshing portion in which said second gear portions of said first and second pinion gears are meshed with each other;
• said first and second housing holes comprising means for supporting the whole periphery of said first and second pinion gears except for said meshing portion;
• a plate member fixed to said cylindrical portion of said casing body and comprising means for bearing a thrust force of said first and second pinion gears by contacting end faces of the first and second pinion gears at a radially outer portion thereof, said plate member having an inner portion spaced from said boss portion to provide a clearance, whereby said first and second housing holes are open to the outside of said differential case through said clearance;
• and
• an end cover having a flange portion fixed to the flange portion of said casing body, a side wall portion comprising means for supporting a thrust force of said pinion gears, and a boss portion for supporting the other of said side gears.