Shrinking

Heating a wheel tire before it is shrunk on

Shrinking is a technical process for the force-fit connection of two parts, which is based on the principle of thermal expansion .

The process is used in many areas of mechanical engineering , for example to firmly connect the shaft and tire of railway wheels . The property is used that substances, especially alloys , expand with increasing heat. In this process, the parts to be connected are manufactured with an interference fit . Both parts cannot be connected to one another at normal temperature or only with great force. However, if the outer part is heated beforehand, which leads to expansion, and then quickly pulled onto the element to be enclosed, it shrinks again when it cools and thus presses itself onto the inner part and remains connected to it. The opposite procedure is what is known as cold or stretching . Both methods can be combined with one another.