Valves and valve actuation – Electrically actuated valve – Solenoid having plural coils
Reexamination Certificate
2000-07-07
2002-07-23
Fox, John (Department: 3753)
Valves and valve actuation
Electrically actuated valve
Solenoid having plural coils
C355S117000
Reexamination Certificate
active
06422533
ABSTRACT:
FIELD OF THE INVENTION
The present relates to solenoid valves and methods of improving performance of solenoid valves.
BACKGROUND OF THE INVENTION
Solenoids, devices made of wire tightly packed into cylindrical coils, are widely used in a variety of applications to convert electrical current into mechanical motion. When current is sent through the coil, a magnetic field is induced within the coil. The magnetic field may be used to move an armature within the coil.
In solenoid valves the movement of the armature is used to move a spool or other valve member which controls flow of a fluid. Changes in the fluid flow such as initiation of flow through the valve may result in fluid forces, such as Bernoulli forces, that oppose the magnetic forces moving the armature and the spool or other valve member. Accordingly, it will be appreciated that it would be advantageous to have solenoid valves that are able to move an armature with greater force.
SUMMARY OF THE INVENTION
A method of improving solenoid valve performance includes suppressing or counteracting at least a portion of the effects of parasitic magnetic flux. A solenoid valve according to the invention eliminates or substantially reduces the flux path for a parasitic magnetic flux which would otherwise travel partially through a housing around a solenoid which is not energized. The parasitic flux path may be eliminated by placing a magnetic block in what would otherwise be the parasitic flux path. According to a particular aspect of the invention, the solenoid valve includes an armature having a pair of permanent magnets with a spacer therebetween.
According to another aspect of the invention, a solenoid valve includes an armature having stepped armature ends and pole pieces having stepped pole piece ends corresponding to the stepped armature ends.
According to still another aspect of the invention, a solenoid valve includes a pair of coils which are independently energizable, and an armature operatively coupled to the coils, the armature having a pair of spaced-apart permanent magnets with poles of each of the magnets being oriented in the spaced-apart direction.
According to a further aspect of the invention, a method of operating a solenoid valve includes energizing one of a pair of independently energizable coils that surround respective ends of an armature, and at least partially preventing parasitic leakage through a flux path that includes the end surrounded by the other of the coils.
According to a still further aspect of the invention, a solenoid valve includes an armature operatively coupled to a coil, the armature having a stepped armature end, and a pole piece having a stepped pole piece end corresponding to the stepped armature end.
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Fox John
Parker-Hannifin Corporation
Renner , Otto, Boisselle & Sklar, LLP
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