| 摘要 |
<p>PURPOSE:To aim at improvement of separation strength, by providing grooves having a plurality of projections and tapering portions on a rear shroud to which an end of a blade formed on a front shroud is attached, and fixing the blade in the groove by ultrasonic welding thereby to fix both the shrouds. CONSTITUTION:A hollow portion 7 of rectangular shape in section is provided in a blade 5 formed inside of a front shroud 1. The blade 5 surrounding the hollow portion 7 includes a side wall 9 and an end portion 9. There is provided a groove 6 on an inner surface of a rear shroud 2 engaged with the end portion 9 of the blade 5. The groove 6 is provided with a plurality of acute-angled projections 10 and tapering portions 12 engaging with end corners 11 of the blade 5 at several or entire areas thereof. The projections 10 are welded to the end portions 9 by ultrasonic wave, while the end corners 11 are also welded to the tapering portions 12 by ultrasonic wave. In this manner, the blade 5 is fixed to the groove 6 by ultrasonic welding thereby to fix both the front and rear shrouds 1 and 2 with each other in an integral manner, thus permitting increase in separation strength and improvement of productivity and efficiency.</p> |
