Patent ID: 6464609
Filing Date: 2002-10-15
Classification: F16H

Abstract:
A control mechanism for a multi-speed transmission having a plurality of selectively engageable torque transmitting mechanisms, said control mechanism comprising:a source of fluid pressure; first, second, and third shift valve means having a spring set position and a pressure set position and being positionable to distribute fluid to and from the torque transmitting mechanisms according to a predetermined schedule to establish six forward ratios in the multi-speed transmission; switching valve means having a spring set position for steady state operation and a pressure set position for transient operation and for distributing fluid to said shift valve means during the steady state and transient operations; high ratio control valve means disposed in fluid communication with said source for distributing fluid pressure, in accordance with the predetermined schedule, to said switching valve means to effect an increasing pressure change in an oncoming one of said torque transmitting mechanisms during an upshift ratio change transient operation; low ratio control valve means disposed in fluid communication with said source for distributing fluid pressure, in accordance with the predetermined schedule, to said switching valve means to effect a decreasing pressure change in an off going one of said torque transmitting mechanisms during an upshift ratio change transient operation; and downshift valve means for directing said pressure distributed by said high ratio control valve means to a bias port on said low ratio control valve means to discontinue pressure distribution therefrom when said increasing pressure achieves a predetermined level.