Bidirectional valve and fuel shut-off device

摘要

A fuel shut-off device in which easier assembly and improved air-tight sealing can be achieved. A partition wall plate is ultrasonically welded to a fixing steplike portion of a case body to form an air-tight bidirectional valve chamber comprising the partition wall plate and the case body. The bidirectional valve chamber accommodates a bidirectional valve composed of a positive pressure valve mechanism and a negative pressure valve mechanism. A negative pressure valve member of the negative pressure valve mechanism and a negative pressure spring are formed into an integral structure with a positive pressure valve member of the positive pressure valve mechanism. The positive pressure valve member is formed into an integral structure with the partition wall plate by the engagement of an engaging ring-shaped member of a valve receiving member and an engaging arc-shaped member of the partition wall plate. These form a sub-assembly which is passed through an opening of the case body at the lower end and assembled to the case body from one direction. This completes the accommodation of the bidirectional valve.