Closing structure of drain role of magnesium alloy oil pan of engine, has many concentric annular sealing protrusions which embed into peripheral section of drain hole and washer provided to head side of drain plug

摘要

An anti-corrosion board (14) is inserted on a screw threaded shaft (6) between a washer (11) on a head (7) side and a peripheral section (13) of an opening of an internal threaded drain hole (4). Many concentric annular sealing protrusions of the anti-corrosion board, embed in the peripheral section and the washer. A plug (5) is formed with the head having a greater diameter than the screw-threaded shaft. The drain hole is formed with a female thread (3) matching the screw thread of the shaft. A through-hole (15) is formed in the anti-corrosion board for passing the shaft. The anti-corrosion board forms the electrical insulation between the washer and the peripheral section. The plug which closes the drain hole of a magnesium alloy oil pan (1), is formed with a metal other than the Mg or Mg alloy.