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A solenoid which has a coil, a ferromagnetic core extending completely through the center of the coil and a ferromagnetic upper pole formed integrally with the core at the lower end of the coil. The upper pole having a diameter larger than the diameter of the core but smaller than the outer diameter

A solenoid which has a coil, a ferromagnetic core extending completely through the center of the coil and a ferromagnetic upper pole formed integrally with the core at the lower end of the coil. The upper pole having a diameter larger than the diameter of the core but smaller than the outer diameter of the coil. A plunger mounted for movement towards and away from the upper pole. The plunger is operably connected to a mass flow control valve and spring biased towards a closed position away from the upper pole. The plunger has a diameter greater than its length and a set of concentric cylindrical ridges extending downwardly to interleave with a corresponding set of upwardly extending concentric cylindrical ridges on a lower pole. An outer, square ferromagnetic casing completes the magnetic circuit by extending from the upper end of the core to the outer surface of the lower pole. The interleaving ridges provide a large surface area for transfer of magnetic flux from the lower pole to the plunger. Two non-magnetic disk springs act to bias the plunger toward closure of the valve, to prevent latching by stopping the plunger from too close an approach to the upper pole, and to hold the plunger in a central position to eliminate friction. The ends of the ridges are grooved to reduce unwanted attraction between the plunger and the lower pole.

대표청구항 ▼

A solenoid controlled valve comprising: a valve; a coil having first and second ends, said coil forming an elongated opening through its center; a ferromagnetic core having first and second ends, said core extending through said coil, within said opening; a first pole located at the first end of bot

A solenoid controlled valve comprising: a valve; a coil having first and second ends, said coil forming an elongated opening through its center; a ferromagnetic core having first and second ends, said core extending through said coil, within said opening; a first pole located at the first end of both said core and said coil, said first pole having a diameter larger than the diameter of said opening; a second pole spaced from and facing said first pole; a plunger having first and second ends, said plunger being mounted between said first and second poles for movement through a limited range towards and away from said first pole, said first end of said plunger having a diameter greater than the diameter of said coil opening, said first end further having a surface which faces the surface of said first pole, said plunger being drawn toward said first pole when current flows through said coil; a ferromagnetic casing surrounding said core, said coil, said first and second poles, and said plunger; said second pole having an outside diameter sized such that the outer surface of said second pole is proximate to the inner surface of said ferromagnetic casing; an opening in the middle of said second pole, linkage extending through said opening to operably connect said plunger with said valve to control the flow through said valve; said second pole having a plurality of concentric cylindrical ridges arranged symmetrically around said linkage opening and extending from said second pole towards said plunger, said plunger having a complimentary set of concentric cylindrical ridges extending from said plunger towards said second pole, said plunger ridges sized and arranged to maintain at least a portion thereof in close interleaving relationship with said cylindrical second pole ridges throughout the limited range of movement of said plunger to provide a plurality of magnetic flux flow paths normal to the direction of movement of said plunger across the gaps between the sides of said second pole ridges and the sides of said plunger ridges; said plunger including a cylindrical disk having a width which is less than its diameter, said plunger ridges depending from one side of said disk at positions spaced radially inwardly from the outer edge of said disk to help distribute the magnetic flux over the surface of the plunger facing said first pole; and spring means biasing said plunger to hold said valve in a desired position when no current flows through said coil.