Other

Minnesota Automotive, Inc.

Raymond Dexter Woodworth

James Edwin Bobrow

Thomas A Rettich

A rotory servovalve is constructed with a cylindrical annular housing and a cylindrical valve element rotatable therewithin. The valve housing has at least two inlet orifices, at least two outlet orifices, at least two first fluid transfer control orifices, and at least two second fluid transfer control orifices. At least two orifices of each type are located on opposite sides of the valve housing from each other. Preferably there is a first end orifice, a central orifice, and a second end orifice of each type. The end orifices of each type are angularly and longitudinally aligned with each other and are angularly offset 180 degrees from a central orifice of the same type. The end orifices of each type have an area equal to one-half the area of the central orifice of the same type and are equally spaced in opposite longitudinal directions from the central orifice of the same type. An imbalance of fluid forces within the servovalve mechanism is thereby avoided, both in a direction perpendicular to the valve axis and in planes passing through and containing the valve axis. By eliminating force imbalances within the valve in high-pressure applications the electrical current requirement and the mass of the components required for the driving motor or rotory solenoid that operates the valve are reduced.

Balanced rotary servovalve

An improved rotary servovalve system employs a rotary magnetic solenoid having an armature that includes at least one permanent magnet. The armature is rotatable relative to a stator formed as an electromagnet which is energizable to create alternative electromagnetic fields having opposite polarities from each other. When deenergized, the stator allows the armature to return to a neutral, null position from positions of extreme rotation in opposite angular directions due to the magnetic force of the permanent magnet of the armature. The armature is coupled to carry a movable valve element in angular rotation therewith, so that flow through the servovalve of the system can occur in alternative directions. Also, the valve element is biased toward a position in which all of the valve ports are closed when power is removed from the rotary solenoid. The control circuit employed in the rotary servovalve system expands the bandwidth of response of the solenoid actuator by compensating for frequency variations in the input command signal and in the feedback signal. This compensation is achieved utilizing a combined proportional, integral, and differential amplification circuit. Also, imbalance of fluid forces within the servovalve mechanism can be avoided by utilizing a pair of inlet orifices, a pair of outlet orifices, a pair of first fluid control orifices, and a pair of second fluid control orifices. The orifices within each pair are located on opposite sides of the valve housing from each other.

Rotary servovalve and control system

A pulse width modulated control signal is applied to inlet and outlet solenoid valves in a closed fluid vehicle brake system. The electronic actuating circuitry can control a fluid brake system in a towed vehicle from a towing vehicle without fluid connections therebetween. The closed fluid brake system provides an electrical feedback signal that tracks an electrical command signal applied by the towing vehicle operator through a manually operated command signal transducer to produce an error signal to maintain a command pressure in the towed vehicle fluid brake system. The inlet and outlet valves are repeatedly opened and closed in accordance with the width of a train of pulses. The pulse width is proportional to the difference between an electrical command signal and an error signal.

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Irvine, CA, United States of America

Raymond Dexter Woodworth