Difference between revisions of "Contact Spring Calculations"
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[[File:One side fixed contact bending spring.jpg|right|thumb|One side fixed contact bending spring]] | [[File:One side fixed contact bending spring.jpg|right|thumb|One side fixed contact bending spring]] | ||
Fig. 6.20: | Fig. 6.20: | ||
− | One side fixed contact bending spring | + | One side fixed contact bending spring<br /> |
− | L = Length of spring | + | L = Length of spring<br /> |
− | E = Modulus of elasticity | + | E = Modulus of elasticity<br /> |
− | B = Width of spring | + | B = Width of spring<br /> |
− | F = Spring force | + | F = Spring force<br /> |
− | D = Thickness of spring | + | D = Thickness of spring<br /> |
− | x = Deflection | + | x = Deflection<br /> |
max = maximum bending force | max = maximum bending force | ||
− | The influence of the dimensions can be illustrated best by using the single side | + | 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: |
− | fixed beam model (Fig. 6.20). For small deflections the following equation is valid: | ||
F= x | F= x |
Revision as of 13:25, 2 April 2014
6.4.7 Contact Spring Calculations
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= x 3 x E x J L³
where J is the momentum of inertia of the rectangular cross section of the beam
J= B x D³ 12
For springs with a circular cross-sectional area the momentum of inertia is
J=BD4/64 D= Durchmesser
To avoid plastic deformation of the spring the max bending force σ cannot be max exceeded
Fmax= 3 x E x D xmax 2L²
The stress limit is defined through the fatigue limit and the 0.2% elongation limit resp.
xmax= 2 x L ² Rp0,2 3 x D x E
and/or
Fmax= B x D ² Rp0,2 6L
- 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