초록 ▼

A transmission gear train has a clutch designed to minimize shift shock upon engagement while still exhibiting relatively rapid initial engagement. To this end, a face cavity is formed in the clutch actuating piston which acts as an accumulator into which hydraulic fluid flows for a period of time a

A transmission gear train has a clutch designed to minimize shift shock upon engagement while still exhibiting relatively rapid initial engagement. To this end, a face cavity is formed in the clutch actuating piston which acts as an accumulator into which hydraulic fluid flows for a period of time after initial clutch engagement. This fluid flow causes clutch pressure to be lower than system main pressure while the accumulator is filling, thereby providing a cushioning effect which reduces shift shock. Use of the accumulator or face cavity eliminates the need for a stepped piston and the additional seals and flow passages normally required for a stepped piston, thus simplifying clutch manufacture and operation.

대표청구항 ▼

An apparatus comprising: a rotatable drive element; a rotatable driven element; and a clutch which selectively couples said drive element to said driven element, said clutch including a plurality of interleaved clutch plates extending between said drive element and said driven element, and a hydraul

An apparatus comprising: a rotatable drive element; a rotatable driven element; and a clutch which selectively couples said drive element to said driven element, said clutch including a plurality of interleaved clutch plates extending between said drive element and said driven element, and a hydraulically actuated piston which is slidable axially of said clutch assembly, said piston having a first axial surface subjectable to hydraulic actuating fluid and an opposed second axial surface facing said clutch plates and engaging one of said clutch plates when said clutch assembly is engaged, wherein said second axial surface has an arcuate face cavity formed therein extending around at least substantially an entire circumference thereof, wherein a bore extends through said piston from said first surface to said face cavity, and wherein said piston seals against said one clutch plate upon clutch engagement to form an accumulator within said face cavity.