Patent ID: 7362208
Filing Date: 2008-04-22
Classification: H01H,Y10T

Abstract:
1. A thermal pellet type thermal fuse comprising: a cylindrical metal casing incorporating a switching component, and a lead member leading out from both end sides of said metal casing, said lead member including a first lead attached to said metal casing by hermetic sealing with an insulating material, and a second lead fixed directly by caulking to said metal casing, said switching component including a weak compression spring, a movable electrode, a strong compression spring, and a thermal pellet sequentially disposed in order from a side of said first lead in said metal casing, an urging force of the compression springs pressing said first lead and said movable electrode into contact at an ordinary temperature, said thermal fuse having an operating temperature establishing an open state between said first lead and said movable electrode by deformation of said thermal pellet caused by heating, wherein materials having different physical or chemical properties are respectively selected for said first lead and said second lead of said lead member to exhibit heat generation or heat radiation differing from each other, and wherein said lead member has said materials selected such that a surface temperature of said metal casing is lower at a side of said second lead than at said side of said first lead when a current is applied, whereby sublimation of said thermal pellet is suppressed and erroneous operation prior to achieving said operating temperature is prevented.