PROBLEM TO BE SOLVED: To stabilize the joint strength between an outer barrel and an inner barrel with a joining material.SOLUTION: An inner barrel outer peripheral groove 41 is formed in the circumferential direction on the outer peripheral surface of an inner barrel 32, and an outer barrel inner peripheral groove 44 is formed in the circumferential direction on the inner peripheral surface of an outer barrel 33. Inner barrel branching grooves 42a-42d and outer barrel branching grooves 47a-47d are formed in the direction of a center core of barrels in such a way that openings are exposed from the end edge of the outer barrel 33. An injection hole 46 communicating with the outer barrel inner peripheral groove 44 is formed in the outer barrel 33. Solder 45 is injected from the injection hole 46 into the outer barrel inner peripheral groove 44 and the inner barrel outer peripheral groove 41 by a solder trowel. As the solder 45 flows through a channel of both outer barrel inner peripheral groove 44 and inner barrel outer peripheral groove 41, the solder 45 can be securely loaded.COPYRIGHT: (C)2013,JPO&INPIT【課題】接合剤による外筒と内筒の接合強度を安定化させる。【解決手段】内筒32の外周面に、周方向に内筒外周溝41を形成する。外筒33の内周面に、周方向に外筒内周溝44を形成する。内筒分岐溝42a~42d、外筒分岐溝47a~47dを、外筒33の端縁から開口が露出するように筒芯方向に形成する。外筒内周溝44に連通する注入孔46を外筒33に形成する。半田コテにより半田45を、注入孔46から外筒内周溝44と内筒外周溝41に注入する。外筒内周溝44と内筒外周溝41とを合わせた流路内を半田45が流れるため、半田45を確実に充填することができる。【選択図】図2
