| 摘要 |
<p>A compression mechanism (20) is provided with a first relief port (31a, 31b) opening only to a first compression chamber (24a), a second relief port (32a, 32b) opening only to a second compression chamber (24b), and a third relief port (33) which can open to both of the first compression chamber (24a) and the second compression chamber (24b).</p> |
