Allegro Microsystems, LLC

Terry R Clapp

Ravi Vig

Daniel S Dwyer

Sandra R Pinelle

Gregory R Bowman

Teri L Tu

Raymond W Engel

Peter J Gilbert

A magnet structure including a magnet and an integral magnetically permeable concentrator and methods for making the same are provided. The concentrator is comprised of a plastic loaded with one or more magnetically permeable materials to a percentage suitable for providing desired magnetic field characteristics. The magnetic element may be comprised of a conventional magnetic material or a plastic loaded with one or more magnetic materials. An insert molding technique is described in which either the concentrator or magnetic element is prefabricated and inserted into a mold which is subsequently filled with a loaded plastic to provide the other component of the magnet structure. In an alternate fabrication technique, both the concentrator and magnet are sequentially formed by injection molding in the same mold. Also described is a magnet structure including a ring magnet having a central aperture in which a steel rod is disposed.

Method for fabricating a magnet structure

A magnet structure including a magnet and an integral magnetically permeable concentrator and methods for making the same are provided. In one embodiment, the concentrator has a substantially planar base and a post extending normal to the base and the magnetic element is a ring magnet having a central aperture through which the concentrator post extends. The concentrator is comprised of a plastic loaded with one or more magnetically permeable materials to a percentage suitable for providing desired magnetic field characteristics. The magnetic element may be comprised of a conventional magnetic material or a plastic loaded with one or more magnetic materials. An insert molding technique is described in which either the concentrator or magnetic element is prefabricated and inserted into a mold which is subsequently filled with a loaded plastic to provide the other component of the magnet structure. In an alternate fabrication technique, both the concentrator and magnet are sequentially formed by injection molding in the same mold. Also described is a magnet structure including a ring magnet having a central aperture in which a steel rod is disposed.

Magnet structure

This invention is a magnetic-field sensor assembly comprising a preformed housing shell having a first end which includes an opening, and a second end which includes a window and having a cylindrical shape with a flattened portion to produce a truncated circular cross-section, a sensor package including an integrated-circuit magnetic-field-sensor chip encapsulated in a protective body with first and second opposite and mutually parallel faces and a plurality of integral conductive leads, each lead having a proximal portion, a distal portion, and a central portion, the proximal portion of each of said plurality of leads extending from said body, the central portion of said plurality of leads extending away from the body and positioned substantially normal the faces of the body, said sensor-package body being positioned in said housing shell part way through said window with said one body face extending outwardly from said housing shell and with said lead distal portions extending from said housing shell through said opening, a magnet having a first end and a second end and positioned in said housing shell with said first end adjacent to said second sensor-package body face, and an endcap adapted to close said opening in said housing shell.

Hall-effect ferrous-article-proximity sensor assembly

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Goffstown, NH, United States of America

Terry R Clapp