Induction heating device for metal strip

An induction heating device for a metal strip, comprising:

• a first induction coil including:
• a first induction coil member and a second induction coil member that are provided in parallel with a metal strip across the metal strip that travels in a longitudinal direction thereof, that are provided such that both ends of each of the first induction coil member and the second induction coil member protrude from the traveling metal strip in a sheet width direction of the traveling metal strip, and that are arranged such that vertical projection images thereof onto the traveling metal strip do not overlap each other in a traveling direction in which the metal strip travels;
• a first electrical connector for electrically connecting one of both ends of the first induction coil member and one of both ends of the second induction coil member;
• and
• a second electrical connector for electrically connecting another one of the both ends of the first induction coil member and another one of the both ends of the second induction coil member;
• a first magnetic core including:
• a first magnetic core member provided between the first induction coil member and the second induction coil member in the traveling direction, the first magnetic core member being provided on one of surface sides of the traveling metal strip and covering a large area of one end portion in the sheet width direction of the traveling metal strip, the large area being on one end portion in the sheet width direction of the traveling metal strip at a side of each of the first induction coil member and the second induction coil member in the traveling direction of the metal strip between the first induction coil member and the second induction coil member, and covering a small area of the one end portion in the sheet width direction of the traveling metal strip at a center portion in the traveling direction of the metal strip between the first induction coil member and the second induction coil member;
• wherein two end portions of the first magnetic core member that are proximate to the respective first and second induction coils have a larger surface area that covers the metal strip over the large area than a surface area of a portion of the first magnetic core member that covers the small area at the center portion of the metal strip, and
• a second magnetic core member provided between the first induction coil member and the second induction coil member in the traveling direction, the second magnetic core member being provided on another one of the surface sides opposite from the one of the surface sides of the traveling metal strip and covering a large area of the one end portion in the sheet width direction of the traveling metal strip, the large area being on one end portion in the sheet width direction of the traveling metal strip at a side of each of the first induction coil member and the second induction coil member in the traveling direction of the metal strip between the first induction coil member and the second induction coil member, and covering a small area of the one end portion in the sheet width direction of the traveling metal strip at a center portion in the traveling direction of the metal strip between the first induction coil member and the second induction coil member;
• wherein two end portions of the second magnetic core member that are proximate to the respective first and second induction coils have a larger surface area that covers the metal strip over the large area than a surface area of a portion of the second magnetic core member that covers the small area at the center portion of the metal strip, and
• a second magnetic core including:
• a third magnetic core member provided between the first induction coil member and the second induction coil member in the traveling direction, the third magnetic core member being provided on the one of the surface sides of the traveling metal strip and covering a large area of another end portion opposite from the one end portion in the sheet width direction of the traveling metal strip, the large area being on one end portion in the sheet width direction of the traveling metal strip at a side of each of the first induction coil member and the second induction coil member in the traveling direction of the metal strip between the first induction coil member and the second induction coil member, and covering a small area of the one end portion in the sheet width direction of the traveling metal strip at a center portion in the traveling direction of the metal strip between the first induction coil member and the second induction coil member;
• wherein two end portions of the third magnetic core member that are proximate to the respective first and second induction coils have a larger surface area that covers the metal strip over the large area than a surface area of a portion of the third magnetic core member that covers the small area at the center portion of the metal strip, and
• a fourth magnetic core member provided between the first induction coil member and the second induction coil member in the traveling direction, the fourth magnetic core member being provided on the another one of the surface sides of the traveling metal strip and covering a large area of the another end portion in the sheet width direction of the traveling metal strip, the large area being on one end portion in the sheet width direction of the traveling metal strip at a side of each of the first induction coil member and the second induction coil member in the traveling direction of the metal strip between the first induction coil member and the second induction coil member, and covering a small area of the one end portion in the sheet width direction of the traveling metal strip at a center portion in the traveling direction of the metal strip between the first induction coil member and the second induction coil member
• wherein two end portions of the fourth magnetic core member that are proximate to the respective first and second induction coils have a larger surface area that covers the metal strip over the large area than a surface area of a portion of the fourth magnetic core member that covers the small area at the center portion of the metal strip.