Difference between revisions of "Contact Spring Calculations"

From Electrical Contacts
Jump to: navigation, search
(Blanked the page)
(Tag: Blanking)
(→‎6.4.7 Contact Spring Calculations)
(47 intermediate revisions by 5 users not shown)
Line 1: Line 1:
 +
===6.4.7 Contact Spring Calculations===
 +
[[File:One side fixed contact bending spring.jpg|right|thumb|One side fixed contact bending spring]]
 +
Fig. 6.20:
 +
One side fixed contact bending spring<br />
 +
L = Length of spring<br />
 +
E = Modulus of elasticity<br />
 +
B = Width of spring<br />
 +
F = Spring force<br />
 +
D = Thickness of spring<br />
 +
x = Deflection<br />
 +
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:
 +
 +
<math>F =
 +
  \frac {3 x E x J}{L^3} x</math>
 +
 +
 +
where J is the momentum of inertia of the rectangular cross section of the beam
 +
 +
<math>J =
 +
  \frac {B x D^3}{12}</math>
 +
 +
 +
For springs with a circular cross-sectional area the momentum of inertia is
 +
 +
<math>J=\piD^4/64</math><br />
 +
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
 +
 +
==References==
 +
[[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]

Revision as of 12:35, 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 = </p> <pre> \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 = </p> <pre> \frac {B x D^3}{12}


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

J=\piD^4/64
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

References

References

Retrieved from "https://www.electrical-contacts-wiki.com/index.php?title=Contact_Spring_Calculations&oldid=2841"