Engagement device in automatic transmission

Claim 1

In an automatic transmission including a housing, a sun gear, a ring gear and a carrier rotatably supporting a pinion on a pinion shaft, said pinion meshing with said sun and ring gears, the improvement comprising: a hub secured to said carrier and extending radially outside of and axially overlapping said ring gear, said hub having a small diameter portion constituting an inner race and having an axially adjacent large diameter portion having external spline-teeth on the outer peripheral wall thereof, the outer peripheral wall of said small diameter portion having a friction surface thereon; a cylindrical outer race fitted on internal spline-teeth of said housing and disposed radially outward of and axially aligned with said inner race; a friction element disposed radially between said inner and outer races for engaging said friction surface on the outer peripheral wall of said small diameter portion and said outer race, said small diameter portion having a radially running hole for conducting lubricating oil into said friction element; a first brake axially adjacent said outer race, said first brake including a plurality of said first friction plates axially slidably fitted on the external spline-teeth of said large diameter portion and a plurality of second friction plates axially slidably fitted on the internal spline-teeth of said housing, said first and second friction plates being interleaved; and a second brake axially adjacent said outer race opposite said first brake, said second brake including a plurality of third friction plates, and a plurality of fourth friction plates axially slidably fitted on the inner spline-teeth of said housing, said third and fourth friction plates being interleaved.