| 摘要 |
In a system in which a housing including a fuel passage is formed by heat welding joining end faces of an upper housing and a lower housing made of a synthetic resin, the melted end portion in the welded portion is pushed out and comes to form a flash. The flash varies in size and shape depending upon the state of melting of the joining end faces and the amount of the portion moved due to the pressing, and the finished housing varies in length. The flash protruding at a portion serving as a fuel passage makes the passage area narrow and increases resistance of the passage, and a weak portion in the flash sometimes drops due to fatigue fracture caused by pulsation of fuel flow.Contact ribs 3b, 13b facing each other at a portion lower than the joining end faces 3a, 13a are provided with space grooves 3c, 13c interposed along the joining end faces 3a, 13a of the upper housing 3 and the lower housing 13, and the joining end faces are melted and pressed so that the contact ribs 3b, 13b of the upper housing 3 and the lower housing 13 may come in contact with each other, thus length of the housing 11 being determined by the contact ribs 3b, 13b. The flash 21 is caused to stay in a staying space 22 closed by the contact ribs 3b, 13b at the time of completing the heat welding. |
