| 摘要 |
PURPOSE:To aim at miniaturization in a bearing and prolongation in its service life, by adjusting a back gap in an outvane and a casing with a spacer being inserted into space between a shoulder part of a shaft and an adapter of a ball bearing, while making an axial thrust in an operating point adjustable to zero. CONSTITUTION:A ball bearing 5 is positioned inside a bearing cover 7 and locked thereto, while a spacer 8 is inserted into space between a shoulder part 4' of a shaft 4 and an end face of an adapter 6. And, the number of the said spacer 8 is increased or decreased whereby the shaft 4 moves to some extent, and an impeller (unillustrated herein) connected to this shaft 4 also moves in an axial direction. With this constitution, a back gap in an outvane (unillustrated herein) and a casing (unillustrated herein) is adjustable so that an axial thrust in an operating point is adjustable to zero. In consequence, miniaturization in the ball bearing 5 supporting the shaft 4 may come to fruition and, what is more, prolongation of its service life is made attainable. |
