| 摘要 |
A method and apparatus for coldworking holes using a reusable tubular seamless sleeve made of shape memory alloys. The apparatus uses a pre-lubricated tubular seamless sleeve made of shape memory alloys having a superelasticity property, a mandrel having a major diameter portion, an end-cap with a rough surface, and an adapting-spacer having a rough complementary surface. The preferred coldworking operation includes the steps of placing the sleeve firmly between the rough surfaces of the end-cap and the adapting-spacer which are carried on a mandrel pulling means, passing forward the major diameter portion of the mandrel through the sleeve whose diameter is therefore elastically expanded and thereafter shrinks to a size sufficiently smaller than the diameter of a hole in a workpiece, inserting the sleeve together with the mandrel into said hole, placing the end-cap against the workpiece, retracting the mandrel backward through and out of the sleeve; thereby elastically expanding the sleeve wall against the hole bore and exerting radial outward forces on the sleeve which in turn transmitting the coldworking force to the hole bore; thereafter the sleeve diameter shrinking to a size sufficiently smaller than the diameter of the coldworked hole to ease the removal the sleeve out of the hole. The sleeve is reusable due to the repeatability of the superelasticity property of shape memory alloys.
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