Press, shrink, and cryogenic fittings

While the invention of the spoked wheel reduced the weight of wooden wheels in the wheelmaking industry, it was shrink-fitting (since the 19th century) that made the difference. ^e century), even more so than the embattage technique, already in use since the late Middle Ages to reduce wheel wear, which is worthy of note, as the ring was then fitted effortlessly, after thermal expansion, but above all because the rigidity of the entire wheel was considerably enhanced as a result. However, it was in the field of artillery that the shrink-fitting technique was truly perfected, as extreme precision was required to give a bi-block tube a much higher strength than that of a monobloc tube of the same dimensions, unless the latter was shrink-fitted. Shrink-fitting has become synonymous with enhanced mechanical properties, and thus with the possibility of lightening a structure or reducing the amount of material required for a given stress, the latter aspect (conservation of resources) being relevant to the consideration of sustainable development in projects.

The shrink-fit assembly method has become widespread, enabling tools to be shrunk and unshrunk in their holders very quickly by induction, for example, or high power to be transmitted with pinions set on axes, virtually supplanting the assembly method which consisted in securing parts together by means of a key in a groove. With speed and weight reduction in mind, advances in mechanics have made it possible to work materials as close as possible to their limits, leading to the development of both theoretical and practical studies. through fatigue tests or numerical simulations.

This article describes the various types of shrink-fit connection between a shaft and a ring, or any other part of revolution that can be fully described (in terms of stresses, deformations and displacements) in polar coordinates. It incorporates a wide range of considerations, including different materials, hollow or solid axles, split or multi-split assemblies, cylindrical or non-cylindrical parts of revolution, rings and axles of different lengths, and assemblies subject to rotation. However, it only briefly addresses the case, dealt with in greater depth in the article [R 730] These include pressure equipment that is subject to specific regulations, and for which a full description in cylindrical coordinates is required.

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