摘要 |
When a cover 18 closes an opening end surface 11d of a boss 11, an annular piece 18a moves close to an annular groove 20 to form a labyrinth structure, and thus a flow path for turbocharged air becomes narrower to produce air resistance, which causes the cover 18 to be hardly closed. Thus, chattering is prevented from occurring, and a relief valve 10 can be prevented from being damaged. |