Patent ID: 8531259
Filing Date: 2013-09-10
Classification: H01F

Abstract:
1. A proportional electromagnet including: a bushing with a cylindrical configuration and made of magnetic material; bottom and top covers connected to two ends of the bushing respectively and each made of magnetic material; a base seat made of magnetic material and in direct contact with the top cover; a liner, of which one end is inserted in the bottom cover and directly welded to the base seat and made of non-magnetic material; an iron core with a conical surface at one end and inserted through the liner and wherein the liner defines a first section located in the liner and wherein the base seat is provided on the first section and defines a second section located outside the liner; a coil unit provided between the bushing and the iron core; a copper ring provided on the first section between the iron core and the base seat to avoid magnetic leakage and improve proportional linearity of magnetic thrust of the proportional electromagnet; a stop provided on the first section of the base seat; and a flange made of magnetic material and acting as a magnetic shield provided between the bottom cover and the top cover to direct magnetic flux toward the base seat and the iron core to stably drive the iron core wherein the liner defines a non-magnetic material portion of a magnetic circuit and where the base seat, the iron core, the bottom cover, and the top cover, in combination, define a magnetic material portion of the magnetic circuit.