ACCURATE DIMENSION MEASURING MACHINE AND ACCURATE INNER DIAMETER MEASURING MACHINE

摘要

PURPOSE: To provide a compact measuring machine which can measure the inner diameter and the like of art object to be measured accurately and at high response speed by converting movement of a probe contacting with the object to variation of optical path length through a tapered face, and detecting it by means of the detecting probe of an optical fiber type laser interferometer. ;CONSTITUTION: Probes 16, 18 are moved in parallel by a linear guide 14, and extended by springs 20, 21 until they are brought in contact with the inner wall of a tube W. When the inner diameter of the tube W is larger than a reference inner diameter, the probe 16 is left, the probe 18 is right, respectively moved, a tapered member 22 is slided right downward along a tapered face 16a, and a specular face 22b is moved downward in parallel. Meanwhile, when the inner diameter is smaller than the reference inner diameter, the specular face 22b is pushed upward. This displacement quantity is detected by means of the detecting probe 42 of an optical fiber type laser interferometer 40. The moved quantity of the specular face 22b is expressed to be contracted by tanϕ times due to the inclination 4 of the tapered faces 16a, 22a, difference against the reference inner diameter is obtaind to be spread by 1/tanϕ, and hence accurate measurement can be performed.;COPYRIGHT: (C)1996,JPO