STRUCTURE FOR FIXING DIAPHRAGM TO DRIVE SHAFT AND METHOD FOR FIXING DIAPHRAGM TO DRIVE SHAFT

摘要

In an electromagnetic control valve (10) configured to cancel out forces acting on a valve body (21) by differential pressure using a diaphragm (3), pressure tightness and durability of the diaphragm (3) are improved. A needle-shaped projection (231) is formed on a lower end of a piston section (23) of a valve rod (2) that is a drive shaft. An insertion hole (17c1) isformed in the center of a diaphragm guide (17c). The center of the diaphragm (3) is stuck on the needle-shaped projection (231) to make it pass through it. The needle-shaped projection (231) is inserted into the insertion hole (17c1) in the diaphragm guide (17c). An end of the needle-shaped projection (231) is spot-welded. The diaphragm (3) is stuck with the needle-shaped projection (231) to fix it to the valve rod (2) without cutting a base fabric (3A) of the diagram (3). A needle-shaped projection (17c2) may be formed on the diaphragm guide (17c) and an insertion hole (232) may be formed in the valve rod (2) so as to press-fit the needle-shaped projection (17c2) into the insertion hole (232).