Plate clutch assembly having a torque transmitting member with an improved lubrication controlling dam structure and method of making the same

A method for cold-forming an inner torque transmitting member of a plate clutch assembly having a plurality of parallel annular clutch plates disposed in an annular space defined between said inner torque transmitting member and an outer torque transmitting member for axial movement with respect to one another between a relative slipping relationship and an engaged relationship, said method comprising:

• cold forming a circular piece of sheet metal into a preform having a radially extending central wall and an annular wall extending axially from an outer periphery of said central wall, said annular wall having a free end;
• forming in said annular wall a series of outer wall sections extending axially to said free end, a series of inner wall sections extending axially to said free end, and opposite side wall sections interconnecting adjacent inner and outer wall sections, said outer wall sections and adjacent side wall sections defining a series of axially extending exterior tooth surfaces and corresponding interior trough surfaces, said series of exterior tooth surfaces and corresponding interior trough surfaces being circumferentially separated from one another by said inner wall sections,
• forming radially extending openings through said outer wall sections of said annular wall, said openings enabling a liquid lubricant fed to said interior trough surfaces to flow outwardly therethrough by centrifugal force to provide lubricant between adjacent faces of the plurality of parallel annular clutch plates disposed radially outwardly of said exterior tooth surfaces;
• and
• stamping said free end of said annular wall with a dam structure forming tool at a position spaced radially inwardly from said exterior tooth surfaces to form, at the outer wall sections and adjacent side wall sections, dam structures associated with each of said exterior tooth surfaces and corresponding interior trough surfaces, each dam structure being disposed radially inwardly of the associated exterior tooth surface and extending radially inwardly of the interior trough surface of said outer wall section and extending to the interior trough surfaces of the adjacent side wall sections to control axial flow of the liquid lubricant and retain the liquid lubricant against axial movement beyond the free end of said annular wall.