A disc spring (sometimes called a “Belleville washer” after the inventor) consists primarily of a convex disc supported at the outer periphery by one force and an opposing force on the center of the disc. Disc springs are used singly, or in stacks, to achieve a desired load and travel. The advantage of a disc spring is that it generates a high force in a very short spring length and with minimal movement when compressed. All Kathysia disc springs are subject to exacting manufacturing and quality control standards. All discs are preset so that they will not significantly relax under load over time.
Belleville washers and other disc spring styles can be used singly or in stacks to achieve a desired load and travel. In general, they function best under conditions requiring a very high load in confined space or short travel. Under these constraints, it is often not practical or even possible to use a coil spring. In disc spring stacks, particularly those with parallel units, friction should be considered. Sliding friction is created at the disc’s adjoining, moving surfaces. As a result, the deflection which occurs when loading a stack of discs will lag as the stack is unloaded (hysteresis). This characteristic may be taken advantage of in shock or oscillatory loaded systems needing damping.
Parallel Stack
If you stack 6 discs in parallel, you gain 6 times the load capacity of a single disc, but your maximum deflection is that of a single disc. For example, one disc spring provides 16kgf @0.5mm deflection, using 6 discs, you would achieve a total load of 96kgf, an O.H. of 9mm, and a total deflection of 0.15mm.
Series Stack
If you stack 5 discs in a series, you achieve 5 times the deflection of one disc, but the same load as a single disc. For example, one disc spring provides 16kgf @0.5mm deflection, using 5 discs, you would achieve a total load of 16kgf, an O.H. of 20mm, and a total deflection of 2.5mm.
Mixed Stacking – Parallel & Series
Belleville washers stacked in series and parallel in combinations can be arranged to produce almost any load-vs.-deflection trend that you need (linear, progressive, regressive, etc.)