| 摘要 |
A spiral rotary member (130) includes a tubular main body section (131) and a fin section (133). The spiral rotary member (130) further includes a spiral tube section (135) that is arranged on the main body section (130) and arranged to be wound around a longitudinal axis in the same direction as the fin section (133) or a direction opposite to the fin section (133); and a diameter change preventing section (137) that prevents a diameter of the spiral tube section (135) from expanding when the spiral tube section (135) is wound in the same direction as the fin section (133), or prevents the diameter of the spiral tube section (135) from contracting when the spiral tube section (135) is wound in the direction opposite to the fin section (133). |
