Fluid handling – Self-proportioning or correlating systems – Self-controlled branched flow systems
Patent
1982-08-04
1985-05-07
Nilson, Robert G.
Fluid handling
Self-proportioning or correlating systems
Self-controlled branched flow systems
137 82, G05D 1600
Patent
active
045151768
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a hydraulic fluid line pressure regulator of the type used to regulate line pressure in an automatic transmission. More particularly, this invention relates to such a system controlled through actuation of a solenoid wherein the actual line pressure is controlled in an open loop system.
2. Description of the Prior Art
The line pressure in an automatic transmission is usually established by connecting the outlet of the hydraulic pump to a pressure regulator valve through which the regulated fluid is directed to selectively operated shift valves, which control the engagement of clutches and brake servos whose selective engagement produces the various speed ratios of which the transmission is capable. If line pressure is too high, the clutch elements engage too quickly producing abrupt and objectionable shifting. If line pressure is too low the clutch elements are engaged over a protracted period, which subjects the clutch elements to excessive wear and heat. Prior art transmissions of the hydraulically actuated type include hydraulic and pneumatic means for varying the line pressure, generally as a function of throttle position. Here it is proposed to regulate the line pressure with an electric solenoid that operates a line regulator valve. In this system, line pressure is varied between a minimum and maximum value according to the duty cycle of the solenoid. In the prior art the electrical solenoids used to regulate line pressure have been expensive precision variable force solenoids. The control systems in the prior art use a closed loop whereby information concerning the magnitude of variations in the regulator line pressure is sensed and applied as input in the form of an error signal.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a line pressure regulator system for an automatic transmission that can be accurately controlled within maximum and minimum values through the operation of a solenoid that alternately opens and closes an orifice whose pressure drop determines the minimum line pressure. It is another object of this invention that the line pressure regulator should employ hydraulic components that are particularly adapted for use and control by an electronically operated solenoid. It is yet another object of this invention that the line pressure can be modulated accurately to the desired pressure using components that are not sensitive to adjustments, that accurately establish the minimum and maximum values and across which leakage of hydraulic fluid is not a significant factor. It is still a further object of this invention that the line pressure regulator system be relatively insensitive to variations in temperature.
In realizing these and other objects this invention provides a first orifice which is biased closed by a spring that urges a ball or needle valve element into a seated position on the orifice seat. When the coil of the solenoid is energized, the valve element is moved against the spring force away from the orifice seat thereby opening the pump outlet to a vent port. A second branch of the regulator in parallel with the first orifice furnishes a pressure relief valve that opens the pump outlet to vent if the line pressure rises to a predetermined value. Another orifice in series with the parallel brances of the solenoid valve and relief valve has a fixed size and therefore provides a fixed pressure drop. The maximum line pressure is established while the first orifice is closed at the pressure at which the relief valve opens. The minimum line pressure is determined while the first orifice is open by the pressure drop across the first and second orifices.
In a second embodiment, the first orifice is similarly opened and closed according to energizing signals applied to and removed from the coil of the solenoid. The first orifice communicates the outlet of the pump to a vent port. A second branch, in parallel with the solenoid-operated valve, furnishes a second orifice having a
REFERENCES:
patent: 2975976 (1961-03-01), Smith
patent: 3099995 (1963-08-01), Raufenbarth
patent: 3602069 (1971-08-01), Mori
patent: 3604288 (1971-09-01), Mori
patent: 3667322 (1972-06-01), Noguchi et al.
patent: 3670598 (1972-06-01), Mohri et al.
patent: 3695122 (1972-10-01), Irie et al.
patent: 3710651 (1973-01-01), Marumo et al.
patent: 3748926 (1973-07-01), Mohri et al.
patent: 3799001 (1974-03-01), Takagi et al.
patent: 3855880 (1974-12-01), Ishimaru et al.
patent: 4283970 (1981-08-01), Vukovich
Byler Richard E.
McCarthy James P.
Ford Motor Company
Harrington Donald J.
McKenzie Frank G.
Nilson Robert G.
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