Worm gear units to the spn standard

The available installation space is restricted and you need a high gear ratio? An SPN worm gear unit offers you the highest ratios in only one gear unit stage, and at the same time it has good vibration-damping properties and runs smoothly even at high ratios. Another special feature is the self-locking function of selected gear ratios, which guarantees that unintentional movements cannot occur during operation. You have the choice.

Drive optimizations are our daily business and yet we are committed to meeting the requirements of the product in a customer-specific, reliable and precise manner for every project. For a well-known weaving machine manufacturer, we have implemented this in a perfect way. The project description of the worm gear can be found here.

Discover your customization options

SPN worm gear unit with stable output-shaft bearing arrangement
SPN worm gear unit with hollow shaft

Basic design of worm gear units

In a worm gear unit a worm drives a worm gear. The worm is similar to a thread, and for each revolution the worm gear is "screwed" by a few teeth. When the worm gear has a large number of teeth, even gear ratios up to i = 200 and beyond can be achieved in just one gear unit stage. The worm and worm gear slide over each other during operation. The high proportion of sliding motion promotes silent running on the one hand, but reduces the efficiency on the other hand. In extreme cases the efficiency of the gearing is deliberately reduced, resulting in a self-locking gear unit.

Due to the large worm gear on the output side, it is also suitable for a hollow-shaft output. Even low-backlash worm gear units are possible if certain design measures are taken.

These are the advantages of the worm gear units to the spn standard

  • High gear ratio in one gear unit stage
  • Low running noises
  • Self-locking possible
  • Angled output
  • Hollow-shaft version possible


These spn products are more suitable for the following characteristics

The spn series at a glance

Worm gear unit F7


  • Gear ratios from 6:1 to 88:1 
  • Gear ratios with self-locking available
  • Housings F-74 to F76 made of aluminium, F78 made of grey cast iron
  • Worm gear hardened and ground
  • Worm gear made of brass

Your benefits

  • Flexible – drive shaft on the right, on the left, on both sides or hollow shaft possible
  • Variable – various mounting positions possible
  • High permissible radial forces – due to large deep-groove radial bearings
  • Low radial backlash – due to low-backlash toothed drive components
  • Simple motor assembly – due to worm shaft with drive bore and parallel-key groove
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Your personal contact

Customized drive solutions result from personal interaction between you and the SPN experts. Here you will find the SPN contact person for your region.