Abstract: For clutch (23) in vehicle driving force transmitting system, having operating states of full engagement, slip engagement and disengagement, there are provided heat generation calculating section (32) calculating per-unit-time temperature increase ?T(up) from heat generation quantity (?t) generated among friction material members of clutch (23), heat dissipation calculating section (33) calculating per-unit-time temperature decrease ?T(down) from heat dissipation quantity f(t) dissipated from the friction material of clutch (23), and clutch temperature estimation calculating process section (31) calculating current clutch temperature Tnow by adding temperature variation ?T to previous clutch temperature Tpv. Heat dissipation calculating section (33) estimates a quantity of lubricating oil passing around the friction material of clutch (23) and uses the estimated lubricating oil quantity for the heat dissipation quantity f(t) dissipated by heat transfer from the friction material to the lubricating oil.

Abstract: A frictional engagement structure includes a first drum arranged at the inner periphery of a transmission casing, a second drum arranged at the inner periphery of the first drum, first friction plates splined to the casing or the first drum, second friction plates splined to the second drum, the first and second friction plates being arranged alternately in the direction of an axis of rotation of the drums, a piston for pressing the first friction plates through a disk spring and ensuring coupling between the first friction plates and the second friction plates to frictionally engage the casing or the first drum with the second drum, and a spring bearing member arranged between the first friction plates and the disk spring and including a plate portion substantially parallel to the first friction plates and the outer peripheral portion arranged substantially perpendicular to the first friction plates and interposed between the disk spring and the first drum or the casing.

Abstract: A frictional engagement structure includes a first drum arranged at the inner periphery of a transmission casing, a second drum arranged at the inner periphery of the first drum, first friction plates splined to the casing or the first drum, second friction plates splined to the second drum, the first and second friction plates being arranged alternately in the direction of an axis of rotation of the drums, a piston for pressing the first friction plates through a disk spring and ensuring coupling between the first friction plates and the second friction plates to frictionally engage the casing or the first drum with the second drum, and a spring bearing member arranged between the first friction plates and the disk spring and including a plate portion substantially parallel to the first friction plates and the outer peripheral portion arranged substantially perpendicular to the first friction plates and interposed between the disk spring and the first drum or the casing.