Disc springs are conical ring elements (washers) with elastic properties which are resistant to axial compression force. Disc springs may be subject to static or dynamic loads.
DIN 2093 standard specifies the requirements that a disc spring needs to comply with: design, production process, production tolerances and performance (Force and Displacement) as well as relaxation at different temperatures allowed and fatigue life cycles to withstand depending on the tension variations they are subject to.
This standard defines different manufacture methods depending on the spring thickness and dimensions (between diameters, and between height and thickness) forming three different groups with the aim to cover a wide spectrum of force and displacement.
The main aspects covered by this standard are:
Only the most relevant aspects of the standard are detailed due to its extension.
The standard establishes the spring classification in three groups depending on their thickness. This distinction affects the manufacture processes. It also defines if the spring should have supporting surfaces (reduced thickness). The groups are:
|GROUP||THICKNESS (t)||SUPPORTING SURFACE (t’)|
|1||< 1.25 mm||NO|
|2||1.25 mm – 6 mm||NO|
|3||> 6 mm (up to 14 mm)||YES|
For the manufacture of disc springs the use of steels with an elasticity module of 206.000 N/mm2 such as DIN 17221 (51CrMoV4) and DIN 17222 (51CrV4) is established as a standard rule. It should be considered that carbon steels DIN 1.1231 (CK 67) and DIN 1.1248 (CK 75) will only be used for the manufacture of Group-1 springs. However, other materials, such as stainless steels or copper alloys, which have different elasticity module, can also be used. You may contact with us for different dimensions and materials which are not included in the standard.
According to the group the spring to be manufactured belongs to, the standard establishes the manufacture procedures as well as the surface finishing:
|GROUP||MANUFACTURE||Upper and lower surface finishing||Internal and external side finishing|
|1||Stamping and rounded edges||Ra < 3.2 μm||Ra < 12.5 μm|
|2||Stamping, ext. and int. diameter machining and rounded edges||Ra < 6.3 μm||Ra < 6.3 μm|
|“Fine-Blanked” stamping and rounded edges||Ra < 6.3 μm||Ra < 3.2 μm|
|3||Hot or cold forging, machining of all surfaces and rounded edges||Ra < 12.5 μm||Ra < 12.5 μm|
It should be considered that the surface and edge finishing does not apply if the pieces are under a “shot-penned” process.
DIN 2093 standard establishes a number of measures for disc springs based on specific external diameters and proportionality in the rest of their measures which allow to comply with the force standards. Three series (A, B and C), which are provided with a different force level (high, medium and low), are defined for each external diameter.
Specific proportionality among its measures, which means the three different force levels, is defined for each series.
In the manufacturers’ catalogue, they are usually identified by the series and external diameter (p.e. A50, C71 or B100). Apart from these pieces defined by the standard, other pieces may be manufactured under the same guidelines, although they do not strictly belong to any of the 3 series.
|Ext D / height||18||28||40|
|Height / thickness||0.4||0.75||1.3|
Dimensional, force and even material hardness tolerances are defined in the standard. These tolerances are different depending on the group the springs belong to and there are variations within each group depending on the piece thickness.
|Material thickness (mm)||Thickness tolerance (mm)||Height tolerance without compression (mm)||Force tolerance at 75% of travel (%)||Hardness (HRC)|
|Group 1||0.2 to 0,6||+ 0.02- 0.06||+ 0.10- 0.05||+ 25- 7.5||42 – 52|
|> 0.6< 1.25||+ 0.03- 0.09|
|Group 2||1.25 to 2.0||+ 0.04- 0.12||+ 0.15- 0.08||+ 15- 7.5|
|> 2.0 to 3.0||+ 0.20- 0.10|
|> 3.0 to 3.8||+ 0.30- 0.15||+ 10- 5|
|> 3.8 to 6.0||+ 0.05- 0.15|
|Group 3||> 6.0 to 14||± 0.10||± 0.30||± 5|
Outside diameter De inside diameter Di
Manufacturing tolerances of the Outside Diameter (De) and the Inside Diameter (Di) are determined by the measuring range of these diameters. We can see these tolerances in the following table:
De or Di
|3 to 6||0 to -0,12||0 to +0,12|
|> 6 to 10||0 to -0,15||0 to +0,15|
|> 10 to 18||0 to -0,18||0 to +0,18|
|> 18 to 30||0 to -0,21||0 to +0,21|
|> 30 to 50||0 to -0,25||0 to +0,25|
|> 50 to 80||0 to -0,30||0 to +0,30|
|> 80 to 120||0 to -0,35||0 to +0,35|
|> 120 to 180||0 to -0,40||0 to +0,40|
|> 180 to 250||0 to -0,46||0 to +0,46|
|> 250 to 315||0 to -0,52||0 to +0,52|
|> 315 to 400||0 to -0,57||0 to +0,57|
|> 400 to 500||0 to -0,63||0 to +0,63|
|> 500 to 600||0 to -0,68||0 to +0,68|