Erroneous oil feed prevention device

An erroneous oil feed prevention device to be provided on an oil feed passage to block insertion of a small-diameter oil feeding nozzle and permit insertion of a large-diameter oil feeding nozzle,

• the device comprising:
• paired flaps each having a slanted surface that is slanted relative to a direction of insertion of the oil feeding nozzle and is to be pressed by the oil feeding nozzle, the paired flaps being slidable in radial directions of the oil feed passage and being turnable in the direction of insertion;
• a turn shaft part about which the flaps turn;
• a support portion supporting the turn shaft part;
• paired extension portions extending from a first flap and a second flap of the flaps toward the second flap and the first flap respectively, being in contact with back surfaces of the second flap and the first flap respectively, and being in sliding contact with the second flap and the first flap in a slide direction respectively;
• a first biasing member configured to bias the flaps to turn in a closing direction;
• and
• a restriction portion configured to restrict the flaps from turning in an opening direction,
• wherein while slanted surfaces are pressed by the oil feeding nozzle, each of the flaps slides outward in radial directions of the oil feed passage to release a turning restriction state of the restriction portion, and after the release, the flaps turn in an integrated manner with the extension portions being in contact with the respective other flaps.