Valve case mounting structure

A valve case mounting structure, the valve case mounting structure including:

• a mounting base;
• and
• a valve case mounted on the mounting base and accommodating a valve element thereinside,
• wherein the mounting base includes
• a valve case supporting portion arranged to support an upper portion of the valve case, and
• a retaining piece extending downward front a peripheral portion of the valve case supporting portion and arranged to retain the valve case,
• wherein the retaining piece includes
• a first engagement hole disposed on its distal end side, and
• a second engagement hole disposed closer to its base end side than the first engagement hole,
• the first engagement hole and the second engagement hole being separated from each other by a predetermined distance,
• wherein a peripheral wall of the valve case includes
• an engagement convex portion arranged to be inserted sequentially into the first engagement hole and the second engagement hole in the course of causing the upper portion of the valve case to be supported by the valve case supporting portion, and
• a holding portion including a holding space arranged to receive a distal end of the retaining piece to regulate an expansion thereof, and
• wherein, when the engagement convex portion is positioned on a distal end side of the first engagement hole, the retaining piece does not reach the holding portion,
• wherein, when the engagement convex portion is moved into position from the distal end side of the first engagement hole to the second engagement hole, the retaining piece is expanded by being pressed from an inside of the mounting base by the engagement convex portion, but the distal end of the retaining piece is inserted into the holding space of the holding portion before the retaining piece becomes uninsertable into the holding space of the holding portion, and
• wherein the distal end side of the first engagement hole is positioned above the distal end of the retaining piece.