| 摘要 |
PURPOSE:To simply reinforce a case with no large cost increase without making it large-sized by burying reinforcing materials made of a material with the strength higher than that of an insulating material forming the case on part of the case. CONSTITUTION:Reinforcing materials 3 and 4 are buried in the side wall 1a of the body of a case and the side wall 2a of a cover. They are buried at the portions where large deformation is generated by the pressure of the arc gas generated by the action of a circuit breaker. Molded articles of a metal plate made of a steel plate and a ceramic material made of silicone nitride are used for the reinforcing material, for example, and they are formed concurrently with the case. The strength of the side wall buried with the reinforcing material has the ratio of about 4.7/13 if the maximum displacement quantities are compared when the reinforcing material having a half length of a beam and the Young's modulus five times that of the material of the beam is buried at the center of the beam assuming that the beam is supported on both ends and a uniform load is applied, for example. |
