Patent ID: 8797129
Filing Date: 2014-08-05
Classification: H01H

Abstract:
1. An electromagnetic contactor, comprising: a pair of fixed contacts disposed to maintain a predetermined interval; a movable contact disposed to be capable of contacting with and separating from the pair of fixed contacts; and an electromagnetic unit driving the movable contact; wherein the electromagnetic unit includes: a magnetic yoke with a U-shaped cross section, having an open upper part; an upper magnetic yoke cross-linked in the open upper part of the magnetic yoke with the U-shaped cross section; a spool disposed on a bottom plate part of the magnetic yoke with the U-shaped cross section, and having an exciting coil wound therearound and a central opening; a movable plunger movably disposed in the central opening of the spool in an axial direction and having a tip end protruding through an opening formed in the upper magnetic yoke, the movable plunger being urged by a return spring; and a tubular auxiliary yoke forming a magnetic path between the movable plunger and the magnetic yoke with the U-shaped cross section when the movable plunger is in an open position, wherein the movable plunger is coupled to the movable contact through a coupling shaft, the upper magnetic yoke is disposed with an annular permanent magnet to surround a peripheral flange part of the movable plunger, and an upper surface of the annular permanent magnet is disposed with an auxiliary yoke to face an upper part of the peripheral flange part of the movable plunger.