Joining Surface Structure for a Plurality of Cases

摘要

A joining surface of a lower case including a plurality of grooves and bolt holes. The plurality of grooves are formed with a substantially arced shape and intersect with each other. The bolt holes are used for tightening. The grooves intersect with each other, and connecting sections of the grooves form a continuous groove that separates the inside of the case from the outside of the case. A liquid gasket is filled in the grooves.