PATH£º TECHNOLOGY   TECHNOLOGY

¡ñEndless belt dynamics culcalation

Time£º2016/2/25 ÉÏÎç 11:25:34 Hit£º
1. Calculate effective tension
(1).From load torque
 
 Te £½ (2000¡ÁTr) / £ä
 Te : Effective tension/(N)
 Tr: Load torque/(N・m)
 d: Pulley diameter/(mm)

(2).From carrying weight

    Te£½ (£¨m1+m2£©¡Á¦Ì1¡Á£ç) / ¦Ç
    m1:Load weight(kg)
    m2: Steel belt weight(kg)
    ¦Ì1: Coefficient of friction between steel belt and belt support (Graph 1)

Holding method  Friction coefficient
Holding by sheet 0.3¡«0.6
Holding by roller 0.05

Graph1

   £ç:Gravitational acceleration
    g £½9.807£¨m£¯£ó2£©
    ¦Ç:Efficiency between steel belt and pulley
    ¦Ç£½0.9

2. Calculate tight side tension
 Tt=Te¡Á(e¦Ì0¦È0)/(e¦Ì0¦È0-1)
 Tt:Tight side tension(N)
    e:base of natural logarithm
    e£½2.718
   ¦Ì0:friction between steel belt and pulley(Graph2)

Type of belt  Friction coefficient Remarks
Steel belt 0.1 For low dust generation pulley
0.2 Pulley made of steel and figure is based on Ra 1.6 (surface finish) 
0.3 High friction pulley

Graph2

  ¦È0: Wrap angle of steel belt against pulley (rad)

 (e¦Ì0¦È0) / (e¦Ì0¦È0-1) is as per graph 3

Wrap angle Coefficient of friction
(¡ã£© 0.1 0.2 0.3
180 3.70924 2.14357 1.63843
175 3.79946 2.18761 1.66666
170 3.89503 2.23433 1.69666
165 3.99644 2.28397 1.72861
160 4.10423 2.3368 1.76267
155 4.21902 2.39312 1.79907
150 4.34151 2.45329 1.83803

Graph3

3.Judge if it can use or not.
  Allowable tensile unit stress ¨RTt / (t¡ÁW)
    t:Thickness of steel belt(mm)
   W:Width of steel belt(mm)
  If above formula is applicable, it can use.
  Graph 4  Allowable tensile unit stress for representative grade.

Item SUS304H SUS632 SUS632 SUS301EH SUS301H
Before aging After aging
Allowable tensile unit stress  40 40 55 45 45
£¨N/mm2£©*2

Graph4

4.Other:

Te=Tt£­Ts・・・・1
Tt/Ts£½e^£¨¦Ì0¡Á¦È£©・・・・・2
Te£ºEffective tension(N)
Tt£ºTight side tension(N)
Ts£ºSlack side tension(N)
e£ºBase of natural logarithms,e=2.71828
¦Ì0£ºFriction coefficient of belt and pulley£¨0.2£©¡ù£±
¦È£ºWinding angle of steel belt against pulley£¨¦Ð£©¡ù2
¡ù1£®Friction coefficient of belt and pulley is based on pulley¡¯s finish 1.6a (SUS).     It may vary by material of pulley and surface finish.
¡ù 2£®Diameter of both driving and driven pulley should be same.
Tt£½Te¡Á2.14357・・・・3
Te=(m1+m2)¡Á¦Ì1¡Á£ç/¦Ç・・・・4
£í1£ºWork weight£¨£ë£ç£©
£í2£ºSteel belt weight£¨£ë£ç£©
¦Ì1£ºFiction coefficient of sliding surface between steel belt and support plate
 £¨0.3¡«0.6£©
£ç£ºGravitational acceleration£¨9.807£©
¦Ç£ºEfficiency of steel belt and roller (pulley)£¨0.9£©
Ts=Tt£­Te・・・・5
T0£½£¨Tt+Ts£©/2・・・・6
T0£ºTheoretical Initial tension£¨N£©
F£½T0¡Á2・・・・7
F£ºShaft load£¨N£©
Shaft load which is calculated from above fomula 7, is multipled by safety factor.  And then, it is necessary to have shaft strength and frame strength which will not cause deflection or the like.However, it will be ideal to use in actual equipment as low tension as possible which will not have a problem on usage.


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