Belleville washers have the highest load capacity of all spring washers. This type of washer is used to solve spring problems of high loads, limited space and small deflections. Belleville washers are usually made from high carbon steel, spring-tempered phosphor bronze, beryllium copper or stainless steel.
Also known as conical spring washers, Belleville washers are disc-shaped. They are essentially springs that act as washers. They get their name from their inventor, Julien F. Belleville, who patented them in 1867. They are conical in shape, with a large outer diameter and a small inner diameter.
The large outer diameter provides a larger bearing surface, and the smaller inner diameter allows for a greater deflection or load-bearing capacity.