graph illustrating calculated characteristics versus actual test results

Actual Test Results versus Calculated Disc Spring Characteristics

The example, in the graph on the left, is typical of most disc springs, and underlines the necessity of limiting maximum deflection to 75 per cent to avoid sharply increasing force and stress characteristics.

As the compressed disc spring nears its 'flattened' condition, the reducing cone angle results in the movement of bearing point toward the centre, thus effectively shortening the 'lever' length and 'stiffening' the spring.

graph illustrating examples of varying cone height/thickness ratios

Varying Cone Height to Thickness Ratios

The ability to change the force/deflection characteristic, by way of varying the cone height to thickness ratio, is a particularly useful feature of the disc spring.

Shown above are some examples of different cone height to thickness ratios, and up to a ratio of 1.5 the disc springs may safely be taken to 'flat' or stacked in columns.

Above ratio 1.5 the disc spring will adopt a regressive characteristic, and is capable of 'push-thro.' if not fully supported. Disc springs with cone height/thickness ratios above 2.0 may invert when compressed toward the 'flat' condition.

Institute of Spring TechnologyMember of UK Spring Manufacturers AssociationBelleville QualityBritish Valve and Actuator Association