| 摘要 |
PURPOSE:To improve measuring accuracy, by forming the major axis part of an oval gear by a porous plate such as a honeycomb plate and a metal foam body, providing porous plates at the surfaces facing the major axis parts and at the surfaces facing the side surfaces of the oval gears, thereby providing a large labyrinth effect, and reducing the amount of leakage from the gap between the gear and the inner wall of a measuring chamber. CONSTITUTION:A part of the tooth at the major axis part of an oval gear, which is indicated by a tached part in the Figure, and a part of the tooth at the minor axis part, which is intermeshed with said major axis part, are cut out. At the cut-out major axis part, a porous plate 30 such as a honeycomb plate, a metal foam plate, or a resin foam plate is provided. In this constitution, a labyrinth effect is obtained when the major axis part of the oval gear is intermeshed, and the amount of leakage is reduced. In order to further improve the effect, porous plates 30b are provided at arc surfaces facing the major axis parts 10a and 20a of the oval gears 10 and 20 and a planes facing both side surfaces of both oval gears. |
