| 摘要 |
PURPOSE:To obtain a small-sized and durable sensor having a great resistance to noise by a constitution wherein a shutter made of a magnet is provided movably in a transmission path of light, and the shutter is opened and shut by the magnets of rotary discs supported by a rotating shaft to transmit an optical pulse. CONSTITUTION:A hermeticaly-sealed container 4 provided with a shutter chamber 11 wherein an optical fiber 5a connected to a light source 6 and a light- receiving optical firber 5b connected to a processing circuit 7 are faced each other on the same axis is arranged in a casing 3 surrounding a rotary shaft 1 rotated by a transmission, etc. of an automobile, whie a spherical shutter 13 made of a magnet is provided movably in the shutter chamber 11. On the other hand, rotary discs 14a and 14b with mabnets 15 arranged on the circumferences thereof so that they held the shutter chamber 11 between are fitted to the rotary shaft 1. Accordingly, an optical pulse can be obtained for the optical fiber 5b by opening and shutting the shutter 13 by the rotation of the discs 14a and 14b. By subjecting this optical pulse to operational processing, the number of rotation can be displayed. |
