For bolted connections a very simple form of compression spring utilizes a hollow washer manufactured from spring steel, although other materials can be specified.
Table 25.1 shows a selection of Belleville washers manufactured to DIN 6796 from spring steel to DIN 17222.
If the disc has its top and bottom surfaces ground to approximately 95% of the appropriate thickness in the table above then bearing surfaces will be formed. These surfaces improve guidance where several discs are used together. Fig. 25.17 shows the disc spring with flats.
A disc spring stack with six springs in single series is given in Fig. 25.18. In this arrangement six times the number of individual spring deflections are available. The force available in the assembly is equivalent to that of a single disc spring. In single series concave and convex surfaces are opposed alternatively.
The methods of assembly illustrated in Figs 25.18 and 25.19 can be combined to give many alternative selections of force and deflection characteristics. In the stack given in Fig. 25.20 there are four disc spring components assembled in series and they each contain two disc springs assembled in parallel. This combination will give a force equal to twice that of an individual disc and a deflection of four times that of an individual disc.
Belleville washers are manufactured by Bauer Springs Ltd, of New Road, Studley, Warwickshire, B80 7LY where full specifications are freely available.
Drawing conventions for these springs are given in Fig. 25.21, and show (a) the normal outside view, (b) the view in section and (c) the simplified representation. These conventions can be adapted to suit the disc combination selected by the designer.
Was this article helpful?