Air vent structure for plug cap.

摘要

A plug cap includes a plug cap body and a rain cover (24) having an air vent aperture (28) for communication between a spark plug mounting hole and the atmosphere. There is provided a sealing member (29) including a shaft portion (30) extending through the air vent aperture (28) and movably inserted therein with play and valve portions (31, 32) formed on projecting portions at opposite ends of the shaft portion (30) and having sizes larger than that of the air vent aperture (28). The shaft portion (30) includes a tapered shaft portion (30b) for closing an outer edge of the air vent aperture (28) by movement of the sealing member (29) toward the spark plug mounting hole, and a vent (33) for communication between the spark plug mounting hole and the atmosphere by movement of the sealing member (29) away from the spark plug mounting hole. An air vent structure for the plug cap reliably prevents water from entering the spark plug mounting hole. <IMAGE>