Patent ID: 6669598
Filing Date: 2003-12-30
Classification: F16H,Y10T

Abstract:
An electro-hydraulic control in a transmission having a continuously variable unit requiring a first pressure level and at least one friction device requiring a second pressure level, said electro-hydraulic control comprising:a source of fluid pressure; a first pressure regulator valve in fluid communication with said source of fluid pressure to limit the pressure of said source to a first predetermined level; a second pressure regulator valve in downstream fluid flow relation with said first pressure regulator valve and having a fluid output pressure limited at a second predetermined level at a value less than said first predetermined level; a variable pressure control valve means in fluid communication with said source and having a variable output pressure communicated with both said first and second pressure regulator valves for providing a control pressure thereto to establish said first and second predetermined levels; said source having first and second output flow volumes and an input portion; and said first pressure regulator valve having a first position wherein an unrestricted port thereof is disposed in fluid communication with said second pressure regulator valve and said second output flow volume from said source is connected through a return port directly with said input portion of said source, a second position wherein said unrestricted port is disposed in fluid communication with said second pressure regulator and said return port is closed, and a third position wherein a restricted output port of said first regulator valve is disposed in fluid communication with said second regulator valve to supply fluid thereto and said return port is closed.