JPS6483138A - Inspecting method of retaining ring - Google Patents

Abstract

PURPOSE:To facilitate detection by a method wherein a retaining ring is removed from a rotary armature, the shape of the retaining ring is changed by bending to generate a tensile stress in the inner peripheral surface thereof, and in this state an examination liquid is made to penetrate into a crack. CONSTITUTION:First a retaining ring is removed from a rotor of a rotary armature by releasing the shrink fit of the ring. Next, a hydraulic jack 2, for instance, is set inside the retaining ring 1 and extended to apply a load in the radius direction F onto the ring 1, so that the shape of the ring be changed to be elliptical. In this state, subsequently, spheres wherein a tensile stress is high relatively. e.g. spheres D1 and D2 of about 45 degrees, are set as part to be examined, and liquid penetrant inspection is executed therefor. Moreover the angular position of the ring 1 in relation to the jack 2 is shifted, and the inspection is executed for the remaining parts by the same process. By this method, an inspection liquid is made to penetrate into a crack, and thus even very small cracks can be detected easily and without fail.