Contact material for thermal fuse and thermosensitive pellet-type thermal fuse using the same

A movable contact comprising:

• a conductive base material provided in a cylindrical case of the thermal fuse so as to contact to both an inner wall surface of the cylindrical case and a fixed contact of the thermal fuse, and the conductive base material is bowl shape and has an outer side surface facing to the cylindrical case and an inner side surface facing to the fixed contact;
• and
• a conductive member provided covering a surface of the conductive base material, wherein
• the conductive member is provided to only partially cover one of or both of the outer side surface and the inner side surface, by providing to at least contact portions with the fixed contact in the inner surface and the cylindrical case in the outer surface, wherein at least one of the inner side surface and the outer side surface has at least one region which is free from the conductive member, and wherein the conductive member is made of a material having a Young's modulus and a rigidity different from a Young's modulus and a rigidity of the conductive base material.

A thermosensitive pellet-type thermal fuse comprising:

• a cylindrical case having favorable electrical conductivity and favorable thermal conductivity,
• a thermosensitive pellet that melts or softens at a specific temperature provided to inside of the cylindrical case;
• a strong compression spring configured to press the thermosensitive pellet;
• an insulating cover closing an opening of the cylindrical case;
• a weak compression spring abutting against the insulating cover;
• a first lead extending through the insulating cover and including an inner end as a fixed contact;
• a movable contact electrically connecting to each of a fixed contact of the first lead and an inner surface of the cylindrical case;
• a sealing resin provided surrounding a portion of the first lead and covering an outer end portion of the insulating cover, and sealing an open end portion of the cylindrical case;
• and
• a second lead disposed at one end of the cylindrical case, wherein
• the movable contact includes a conductive base material in a bowl shape having an outer side surface facing to the cylindrical case and an inner side surface facing to the fixed contact and a conductive member covering the conductive base material, and
• the conductive member is provided to only partially cover one of or both of the outer side surface and the inner side surface, by providing to at least contact portions with the fixed contact in the inner surface and the cylindrical case in the outer surface, wherein at least one of the inner side surface and the outer side surface has at least one region which is free from the conductive member, and wherein the conductive member is made of a material having a Young's modulus and a rigidity different from a Young's modulus and a rigidity of the conductive base material.