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Home / About BEVI / Knowledge bank / Advice on choice of worm gear

Advice on choice of worm gear

Selecting the correct worm gear can be a challenge. There is a lot you need to know. BEVI's transmission experts are happy to help you make the right choice.

The following factors should be considered when choosing the right gear for a given application:

  • Type of machine to be commissioned
  • Ambient temperature
  • Surroundings (dust, moisture, acid, frost, tropical heat etc)
  • Drive motor (type and characteristics)
  • Type of coupling between drive motor and gear, i.e. belt, friction, direct or variable speed
  • Desired output torque required at output shaft
  • Input and output speed
  • Mounting positions
  • Service factor

Determining the service factor (Sf)

The service factor is determined by the following characteristics:

  • Working hours per day
  • Workload
  • Life span
  • Work cycle
Formula for calculating the service factor (SF):

SF= F1 x F2 x F3

Factor F1 - working hours and workload

Very variable
3-4 0,8 1 1,5
8-10 1,0 1,2 1,8
10-24 1,4 1,6 2

Factor F2 - desired lifespan

Desired lifespan


10 000    0,8
15 000    1,0
20 000    1,4

Factor F3 - work cycle

Number of start/stop per
6 1,0
60 1,2
120 1,4
Anders Holgert

Product manager transmission

Direct: +46 499-271 28
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