Patent ID: 6422356
Filing Date: 2002-07-23
Classification: F16H

Abstract:
An automatic transmission comprising:a speed-change gear mechanism; a band brake including a drum connected to an element of the speed change gear mechanism for rotation therewith and a flexible band strip wound around the drum; a hydraulic servo for tightening the flexible band strip on the drum in a speed-change operation, said hydraulic servo comprising: a cylinder casing; a piston slidably mounted within the cylinder casing; a rod driven by said piston and engageable with one end of the flexible band strip; a first spring disposed between said piston and said rod; and means limiting compression of said first spring; and an elastic member mounted within said cylinder casing between the piston and the rod for transmission therethrough of a hydraulic force from the piston to the rod to tighten the flexible band strip on the drum, said elastic member isolating said piston from oscillations in movement of the rod generated by frictional force between said band strip and said drum in tightening the flexible band strip, said elastic member providing elastic dampening between said piston and said rod with said first spring at the limit of its compression.