disc spring tolerances

The following maximum deviations are laid down in DIN 2093. They are valid for all Schnorr disc springs as per the DIN and Schnorr works standards. In general Schnorr also apply these tolerances to special sizes, however, if they deviate greatly from the DIN springs, wider tolerances must be specified. This applies, for example, to our ball-bearing disc springs (section 8.1 and 9.5). If closer tolerances are required than those specified in DIN 2093, please contact us.

Diameter Tolerances

For the outside diameter D_e, the tolerance field h12 is applied, and for the inner diameter D_i, it is H12.

For the concentricity the tolerances applied are:
for D_e to 50mm: 2 . IT 11
for D_i over 50mm: 2 . IT 12   

Thickness Tolerances

Tolerances allowed in DIN 2093 are as follows: 

For springs in group 3 the tolerances is applied to the reduced thickness t’. 

We used the thickness to ensure that spring loads are within tolerance and therefore will in some cases deviate from the above figures.  

Overall Height Tolerances

To ensure the specified spring forces, DIN 2093 allows the overall height tolerance to be slightly exceeded.

Load Tolerances 
 
Single Disc Springs

For single disc springs the following maximum deviations are allowed:

With a single spring the spring force must be checked at the height l_o – s. This should be carried out with the spring pressed between two lubricated, hardened, ground and polished plates. Measurements are always taken in loading direction.

For the determination of the variation between loading and unloading, a stack of 10 springs in single series is used. The stack is fitted with a guide rod and abutment plates inserted at both ends. Before testing, the stack should be loaded with twice the spring force F_{(s = 0.75 ho}).

During unloading the measured spring force at the length L_o – 7.5 h_o must at least reach the percentage of the loading characteristic shown in the table (figure 28).

Figure 28 - click to enlarge