Limited slip differential gear mechanism

Claim 1

In a limited slip differential gear mechanism of the type including a pinion shaft rotating integrally with a differential gear casing, pinion gears rotatably attached to said pinion shaft, side gears engaged with said pinion gears and splined to axles, and a plurality of first and second clutch plates alternately disposed between said side gears and said differential gear casing, a lug portion of an inner surface of each said first clutch plate engaging with an outer surface of said side gear, and a lug portion on an outer surface of each said second clutch plate engaging with an inner surface of said differential gear casing, whereby lubricating oil from a reservoir forms lubricating oil films in clearances between confronting surfaces of adjacent said first and second clutch plates, and wherein upon rotation of said clutch plates during use of said mechanism said oil films tend to flow from said clearances due to centrifugal force, the improvement comprising means for retaining the lubricating oil in said clearances and for forcing lubricating oil under pressure into said clearances, said means comprising: a plurality of concave recesses formed in at least one of said confronting surfaces over substantially the entire said surface, each of said recess having a concave pyramidal configuration defined by planar surfaces converging at an apex.