Contact Spring Calculations

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6.4.7 Contact Spring Calculations

One side fixed contact bending spring

Fig. 6.20: One side fixed contact bending spring
L = Length of spring
E = Modulus of elasticity
B = Width of spring
F = Spring force
D = Thickness of spring
x = Deflection
max = maximum bending force

The influence of the dimensions can be illustrated best by using the single side fixed beam model (Fig. 6.20). For small deflections the following equation is valid:

F = \frac {3 x E x J}{L^3} x

where J is the momentum of inertia of the rectangular cross section of the beam

J = \frac {B x D^3}{12}

For springs with a circular cross-sectional area the momentum of inertia is

J=\pi D^4/64
D= Durchmesser

To avoid plastic deformation of the spring the max bending force σmax cannot be exceeded

\sigma _{max} = \frac {3 x E x D}{2L^2}x_{max}

The stress limit is defined through the fatigue limit and the 0.2% elongation limit resp.

x _{max} = \frac {2 x L^2}{3 x D x E}R_{p0,2}


and/or

F _{max} = \frac {B x D^2}{6L}R_{p0,2}


  • Special Spring Shapes
    • Triangular spring

      • Deflection x= L³ F 2 x E x J

      = x L³ D³ 6 x F E x B

      Max. bending force Fmax= 1 8 x F x L B x D²

    • Trapezoidal spring

      • Deflection x= x L³ E x J F (2 + B /B )

      x= x L³ E x B x D³ 12 x F (2 + B /B ) min ma

      Max. bending force

      Fmax= 1 8 x F x L (2 + B /B ) x B x D² min max max

    References

    References

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