To improve reliability by enhancing impact strength of a joining member by setting an angle formed with the free edge in a contact plane end part of one metallic material not less than a specific angle or to a specific range angle in the case of joining one metallic material and a metallic material having rigidity smaller than this.
A copper material as a dissimilar material 1 having smaller rigidity and higher melting point and electric conductivity than an aluminum material as one metallic material 2, is used in a contact point part of a movable side current- carrying contactor as a current-carrying contactor material of a circuit breaker for electric power, and an aluminum material is used in a part except for it. A joining interface is put on the copper material by frictionally bringing the copper material and the aluminum material into pressure contact with each other, and an angle formed with the free edge in a contact plane end part is set not less than 120° or to 55° to 85°. Thus, when the copper material is used in a contact point part of the movable side current-carrying contactor and a lightweight aluminum material is used in a part except for it, electric conductivity is enhanced, and melting damage is reduced, and a large electric current can be excellently opened/closed even if a shape becomes small by weight reduction.
ITO YOSHIYASU
SUZUKI KATSUMI
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