Planetary gear transmission systems or components – Fluid drive or control of planetary gearing – Fluid controlled mechanical clutch or brake
Reexamination Certificate
2002-12-18
2004-08-17
Pang, Roger (Department: 3681)
Planetary gear transmission systems or components
Fluid drive or control of planetary gearing
Fluid controlled mechanical clutch or brake
C477S127000, C137S625660
Reexamination Certificate
active
06776736
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates generally to the field of hydraulic circuits utilized in automatic transmission systems and, more particularly, to a Self-Regulating Reverse Boost Valve for use in General Motors 4L80E transmissions.
Automatic transmission systems of the prior art have a hydraulic circuit sub-system, which includes at least a hydraulic pump, a valve body having fluid conducting passages or circuits, input and exhaust ports formed within the fluid circuits, and a plurality of spool valves so-called because of their resemblance to sewing-thread type spools. Such valves are comprised of generally cylindrical pistons having control diameters or lands formed thereon, which alternately open and close the ports to the fluid circuits to regulate the flow and pressure of automatic transmission fluid (hereinafter “ATF”) in order to actuate different components of the transmission. It will be understood that in describing hydraulic circuits, ATF usually changes names when it passes through an orifice or control valve in a specific fluid circuit.
In the General Motors (hereinafter “GM”) 4L80E transmission the Reverse Boost Valve is activated by Torque Signal (hereinafter “TS”) fluid pressure from the Variable Force motor and operates against the force of the Pressure Regulator valve spring. Such TS fluid pressure induced movement forces the Pressure Regulator valve to move against ATF supply from the hydraulic pump thereby boosting line pressure in relation to engine torque. When Reverse gear range is selected, reverse fluid pressure also forces the Reverse Boost valve to move toward the Pressure Regulator valve to boost line pressure.
Common service problems in the GM 4L80E transmission are an uncontrollable rise in main line hydraulic pressure (i.e. upwards of 500-600 psi), high line pressure in Reverse gear, broken direct clutch drums, and/or broken cases, which result from excessive Torque Signal pressure leaking past the original equipment manufacture (hereinafter “OEM”) Boost Valve and into the Reverse fluid circuit. Thus, the present invention has been developed to resolve this problem and other shortcomings of the prior art.
SUMMARY OF THE INVENTION
Accordingly, the present invention is a Self-Regulating Reverse Boost Valve Assembly for an automatic transmission such as the GM 4L80E transmission including an internal check valve mechanism that is actuated whenever Torque Signal pressure to the present Reverse Boost Valve Assembly exceeds a predetermined level (i.e. 95-100 psi). The excess ATF pressure is diverted to fluid exhaust circuits via an internal fluid channel formed in the present valve to the transmission sump. In this manner excessive main line pressure, excessive line pressure in Reverse gear, broken direct clutch drums, and/or damaged transmission cases are avoided.
Other features and technical advantages of the present invention will become apparent from a study of the following description and the accompanying drawings.
REFERENCES:
patent: 5399130 (1995-03-01), Long
patent: 5743823 (1998-04-01), Younger
patent: 6022085 (2000-02-01), Ganzel et al.
patent: 6099429 (2000-08-01), Younger
patent: 6485388 (2002-11-01), Kim et al.
patent: 6619323 (2003-09-01), Stafford
patent: 6712726 (2004-03-01), Jackson et al.
Jackson Scott C.
Stafford Maura Jane
Pang Roger
Rey Clifford F.
Sonnax Industries, Inc.
LandOfFree
Self-regulating reverse boost valve assembly does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Self-regulating reverse boost valve assembly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Self-regulating reverse boost valve assembly will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3333490