A Belleville washer, also known as a Belleville spring washer or conical washer, is used to distribute the load of a threaded fastener. It can also be used as a spacer, spring, shim, locking device, or for reinforcing and to reduce vibration. Its cupped shape provides flexibility and helps prevent loosening.
The Belleville is a disk spring that applies pressure to the connection once you clamp down on it with the proper amount of force. The advantage of this washer is that it applies clamping pressure along a continuous arc pattern, instead of concentrating it at one point the way a split-ring lockwasher does.
In the different fields, if they are used as springs or to apply a flexible pre-load to a bolted joint or bearing, Belleville washers can be used as a single spring or as a stack. In a spring-stack, disc springs can be stacked in the same or in an alternating orientation and of course it is possible to stack packets of multiple springs stacked in the same direction.
Disc springs have a number of advantageous properties compared to other types of springs:
Thanks to these advantageous properties, Belleville washers are today used in a large number of fields.