| 摘要 |
<p>PURPOSE:To improve reliability and exhaust efficiency through the non-collision contact between the laps by setting the inscribed circle radius of the lap of either of a circling scroll and a stationary scroll in such a way that it gradually becomes smaller from a scroll start toward a scroll end. CONSTITUTION:Either of a circling scroll 3 and a stationary scroll, and for instance, the inscribed circle radius R of the lap 3A of the circling scroll 3 is set in such a way that it gradually becomes smaller from a scroll-start toward a scroll-end. As above, the lap wall surface of either scroll member is in advance formed by having it shifted in the direction of the radius against a theory involute curve in consideration of the thermal expansion quantity of the circling scroll 3 and consequently a relative thermal expansion quantity difference form the stationary scroll. On account of this, a vacuum pump can be operated without any collision-contact between the laps and with a fine gap kept. Accordingly, reliability and exhaust-efficiency can be improved.</p> |
