Power plants – Pressure fluid source and motor – Condition responsive control of pump or motor displacement
Patent
1978-05-24
1979-06-19
Geoghegan, Edgar W.
Power plants
Pressure fluid source and motor
Condition responsive control of pump or motor displacement
60448, 60449, 60DIG2, F16H 3946
Patent
active
041582900
ABSTRACT:
An electro-hydraulic control for a hydrostatic transmission including a variable displacement hydraulic pump, a fixed displacement hydraulic motor, and fluid operable strokers to vary the displacement of the pump. The electro-hydraulic control is in series between the charge pump and the standard manual controller and determines the pressure of the charge fluid ported to the standard controller. The electro-hydraulic control includes a spool biased toward a first position to port fluid from the charge pump to the standard controller, and biased toward a second position to relieve to tank the pressure of fluid ported to the manual controller. The biasing toward the second direction is accomplished, in part, by pressure in a fluid chamber exerting a biasing force on the spool, the fluid chamber being in communication with drain through a variable orifice which is variable in response to a pressure command signal. This signal is generated by control logic including a horsepower command signal generator which is variable to correspond to a maximum desired input horsepower, and circuitry providing a horsepower approximation signal representing the product of motor output speed and the instantaneous pressure command signal. The circuitry compares the horsepower command and horsepower approximation signals and generates a new pressure command signal tending to minimize the difference between the horsepower command and approximation signals. As a result, the commanded maximum system pressure varies, such that the product of maximum system pressure and motor output speed (proportional to pump flow) is constant, for a given input horsepower setting.
REFERENCES:
patent: 2588742 (1952-03-01), McCallum
patent: 3365886 (1968-01-01), Moon
patent: 3864915 (1975-02-01), Metailler
patent: 3924410 (1975-12-01), Cornell et al.
Eaton Corporation
Geoghegan Edgar W.
Kasper L.
McCloskey R. J.
Yakimow J.
LandOfFree
Electro-hydraulic controller does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electro-hydraulic controller, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electro-hydraulic controller will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-52956