Disc Springs to DIN 2093: Description

The DIN 2093 specification classifies disc springs into three groups:

	GROUP 1 Under 1.25mm thick. Cold formed - Radiused edges Without bearing flats.
	GROUP 2 1.25mm thick up to and including 6mm. Cold formed Machined (or "fine blanked") and radiused edges Without bearing flats.
	GROUP 3 Above 6mm thick. Fully machined from forged blanks With bearing flats and thickness reduced.

The larger diameter disc springs, in excess of 6mm thickness, of necessity have larger diametral clearances. To minimise the possibility of bearing point misalignment when disc springs are stacked in series i.e. "back-to-back", flats are machined on the upper inside and lower outside diameter edges.

However, the introduction of this bearing flat also moves the position of the points of contact, thus reducing the effective radial width of the disc spring and increasing its stiffness.

To ensure that disc springs with bearing flats have similar characteristics to the same size disc springs without flats, the nominal thickness is reduced (see table below).

Given that the overall height of a disc spring with or without bearing flats is the same, the cone height of the disc spring with bearing flats will be greater by the amount of the thickness reduction.

NOTE: The catalogued cone height dimensions (ho) do not include the appropriate increase for those disc springs in excess of 6mm thickness, which incorporate bearing flats.