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| − | ===6.4.7 Contact Spring Calculations===
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| − | Fig. 6.20:
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| − | One side fixed contact bending spring
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| − | L = Length of spring
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| − | E = Modulus of elasticity
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| − | B = Width of spring
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| − | F = Spring force
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| − | D = Thickness of spring
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| − | x = Deflection
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| − | max = maximum bending force
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| − |
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| − | The influence of the dimensions can be illustrated best by using the single side
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| − | fixed beam model (Fig. 6.20). For small deflections the following equation is valid:
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| − |
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| − | F= x
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| − | 3 x E x J
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| − | L³
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| − |
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| − | where J is the momentum of inertia of the rectangular cross section of the beam
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| − |
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| − | J=
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| − | B x D³
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| − | 12
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| − |
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| − | For springs with a circular cross-sectional area the momentum of inertia is
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| − |
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| − | J=BD4/64
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| − | D= Durchmesser
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| − |
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| − | To avoid plastic deformation of the spring the max bending force σ cannot be max
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| − | exceeded
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| − |
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| − | Fmax= 3 x E x D xmax
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| − | 2L²
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| − |
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| − | The stress limit is defined through the fatigue limit and the 0.2% elongation limit
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| − | resp.
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| − |
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| − | xmax= 2 x L ² Rp0,2
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| − | 3 x D x E
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| − |
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| − | and/or
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| − |
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| − | Fmax= B x D ² Rp0,2
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| − | 6L
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| − |
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| − |
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| − | *'''Special Spring Shapes'''
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| − |
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| − | *'''Triangular spring'''
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| − |
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| − | Deflection
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| − | x= L³
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| − | F
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| − | 2 x E x J
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| − |
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| − | = x L³
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| − | D³
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| − | 6 x F
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| − | E x B
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| − |
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| − | Max. bending force
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| − | Fmax= 1 8 x F x L
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| − | B x D²
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| − |
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| − | *'''Trapezoidal spring'''
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| − |
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| − | Deflection
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| − | x= x L³
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| − | E x J
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| − | F
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| − | (2 + B /B )
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| − |
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| − | x= x L³
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| − | E x B x D³
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| − | 12 x F
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| − | (2 + B /B ) min ma
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| − |
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| − | Max. bending force
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| − |
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| − | Fmax= 1 8 x F x L
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| − | (2 + B /B ) x B x D² min max max
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| − |
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| − | ==References==
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| − | [[Application Tables and Guidance Data for the Use of Electrical Contacts#References|References]]
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