Difference between revisions of "Contact Spring Calculations"

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(→‎6.4.7 Contact Spring Calculations)
(→‎6.4.7 Contact Spring Calculations)
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Max. bending force
 
Max. bending force
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:<math>\sigma _{max}= \frac {18 x F x L}{(2 + B_{min} /B_{max})} x D^3</math>
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:<math>\sigma _{max}= \frac {18 x F x L}{(2 + B_{min} /B_{max}) x B_{max} x D^3 }</math>
 
</ul>
 
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==References==
 
==References==
 
[[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]
 
[[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]

Revision as of 14:27, 2 April 2014

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 = \frac {F}{2 x E x J}L^3


      = \frac {6 x F}{E x B}x \frac{L^3}{D^3}


      Max. bending force

      \sigma _{max}= \frac {18 x F x L}{B x D^2}
    • Trapezoidal spring

      • Deflection

      x= \frac {F}{(2 + B_{min} /B_{max})}\times \frac{L^3}{E x J}


      x= \frac {12 x F}{(2 + B_{min} /B_{max})}\times \frac{L^3}{E \times B \times D^3}


      Max. bending force

      \sigma _{max}= \frac {18 x F x L}{(2 + B_{min} /B_{max}) x B_{max} x D^3 }

    References

    References

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