| 摘要 |
PURPOSE: To provide an axle incorporated with a rotational speed detector which is compact, readily assembled and can perform precise detection in a low speed condition. CONSTITUTION: A sensor 31 is fixed to an immovable portion (second screen 20) of a labyrinth seal assembly 12 for protecting a bearing 6 which is provided between a rotational portion and a fixed portion 2 of an axle 3, while fixing an annular element 30 to a movable portion (first screen 15) of the assembly 12. The annular element 30 has substantially a uniform width in which an N pole and an S pole of a permanent magnet, for instance, are alternately arranged in a circumferential direction of the outer surface with a substantially predetermined pitch to generate periodic signals in proportion to the number of Ns and Ss that pass by the sensor 31 in a unit time, thereby detecting the rotational speed of the axle 3. |
