Patent ID: 8714178

Claim:
A valve stem connection structure of a pressure reducing valve for connecting a valve stem ( 30 ) to a diaphragm rod ( 68 ) joined to a center portion of a diaphragm ( 16 ), the valve stem ( 30 ) coaxially joined to a valve body ( 29 ) of a valve mechanism ( 15 ) housed in a body ( 17 ), characterized in that an insertion recess portion ( 72 ) opened toward the valve mechanism ( 15 ) is coaxially provided in the diaphragm rod ( 68 ), a reduced diameter stem portion ( 30 a ) and a pair of enlarged diameter stem portions ( 30 b , 30 c ) are provided in one end portion of the valve stem ( 30 ), the enlarged diameter stem portions ( 30 b , 30 c ) provided respectively on opposite sides in an axial direction of the reduced diameter stem portion ( 30 a ) and each having a diameter larger than that of the reduced diameter stem portion ( 30 a ), a holding plate ( 74 ) formed to have a substantially U-shaped cross section while having an engaging recess portion ( 73 ) opened to one side with a width larger than an outer diameter of the reduced diameter stem portion ( 30 a ) but smaller than outer diameters of the enlarged diameter stem portions ( 30 b , 30 c ) is inserted into the insertion recess portion ( 72 ) while the reduced diameter stem portion ( 30 a ) is loosely inserted into the engaging recess portion ( 73 ) and thus the one end portion of the valve stem ( 30 ) is held by the holding plate ( 74 ) to be immovable relative to the holding plate ( 74 ) in the axial direction, and the holding plate ( 74 ) and the diaphragm rod ( 68 ) are connected to each other by causing an engaging ring ( 78 ) expandable and contractable in a radial direction of the valve stem ( 30 ) to engage with an arc-shaped first engaging groove ( 76 ) provided in an outer periphery of the holding plate ( 74 ) and an annular second engaging groove ( 77 ) provided in an inner periphery of the insertion recess portion ( 72 ) to correspond to the first engaging groove ( 76 ).