Installation guidelines for Belleville washers

Conical shaped disc springs, or Belleville washers, are a proven energy storage system, but some care is needed in installation, as Alex Martin of Belleville Springs explains.

Disc springs are conical shaped washers, designed to be loaded in the axial direction only.

They can be statically loaded, either continuously or intermittently, or cyclically deflected (dynamically loaded).

Infinitely variable spring characteristics can be achieved by the arrangement of disc springs into stacked columns.

Despite the fact that they have been around since the nineteenth century, their use should still be given consideration, and no more so than in the area of installation.

Proper guidance and location of disc springs is essential to their performance, and will ensure that the desired characteristics and repeatability is achieved.

Recommended guide clearances are provided in the tolerance tables which Belleville Springs provides, and it is also necessary to pay some attention to the nature of the guidance and seating surfaces.

Much depends on the severity of duty in the application; if the disc is to be used as a means of providing a static clamping force on mild steel or cast/forged steel surfaces, this is probably satisfactory.

However, if the seating faces are in aluminium, copper, brass etc; then it is preferable to provide a hardened thrust washer to alleviate face damage/indentation.

Dynamic applications, involving large numbers of deflection cycles, will require that in addition to hardened seating faces the guidance surfaces must also be sufficiently hard to prevent excessive wear or "stepping".

For both support washers and guide elements, a polished surface with hardness of 58HRC is sufficient, and case depth should be at least 0.60mm.

Nitride hardening is permissible, providing that the hardened surface layer is adequately supported.

A most important aid to efficient and extended life of disc springs is the provision of some form of lubrication.

For relatively low-duty disc spring applications, ie with small numbers of deflection cycles, a liberal application of suitable solid lubricant (eg molybdenum-disulphide grease) applied to the contact points and locating surfaces of the spring, is adequate.

For more severe applications of a dynamic or highly corrosive nature, the disc springs will benefit from maintained lubrication, and are often housed in an oil or grease filled chamber.

Back to top