Patent ID: 8256558

Claim:
A differential system comprising: a pair of first and second differential output shafts having respective proximal ends facing each other; a pair of first and second differential side gears fixed on the proximal ends of the respective first and second differential output shafts, wherein the first differential side gear on the first differential output shaft is peripherally formed on a distal side surface thereof with clutch-teeth; an input gear supported on the first differential output shaft so as to be rotatable relative to the first differential output shaft, wherein the input gear has a surface faced toward the first differential side gear; a pinion shaft supported by the input gear so as to be rotatable integrally with the input shaft; a bevel pinion pivoted on the pivot shaft and meshing with the differential side gears; a clutch disc provided on the first differential output shaft between the input gear and the first differential side gear so as to be rotatable relative to the first differential output shaft and to be axially slidable along the first differential output shaft, wherein the clutch disc has opposite first and second surfaces, wherein the first surface of the clutch disc faces the clutch-teeth of the first differential side gear and is peripherally formed thereon with clutch-teeth which is adapted to mesh with the clutch-teeth of the first differential side gear, and wherein the second surface of the clutch disc faces the surface of the input gear and is integrally formed with a lock pin distally projecting therefrom through the input gear so as to have a distal end outside of the input shaft; a cam mechanism interposed between the second surface of the clutch disc and the surface of the input gear, wherein the cam mechanism generates an axial thrust force of the clutch disc when the clutch disc and the input gear differentially rotate; and a differential lock operation device engaged to the distal end of the lock pin and adapted to push the clutch disc toward the first differential side gear, wherein the differential lock operation device is adapted to push the clutch disc toward the first differential side gear so that, as soon as the clutch-teeth of the clutch disc pushed by the differential lock operation device touches the clutch-teeth of the first differential side gear, the cam mechanism activates to generate the thrust force of the clutch disc so as to complete meshing of the clutch-teeth of the clutch disc with the clutch-teeth of the first differential side gear, thereby locking the first differential side gear to the input gear via the clutch disc.