| 摘要 |
PURPOSE: To obtain a structure for air spring case having a reference line structure of different reflectance for sensing a microvariation of a fluid utilizing the reflected light. CONSTITUTION: In order to sense a microvariation of a fluid utilizing a reflected light, an air spring case 1 is fixed to a hole made in a pipe 3 for fluid path. Reference lines A, B, C, D having reflectance different from that of the air spring case 1 are provided on the outer circumferential wall of the air spring case 1. Up/down movement of the reference line, incident to expansion/ contraction of the air spring case 1, is captured utilizing the reflected light thus sensing microvariation of a fluid. |
