Zero backlash worm gearing for pan and tilt

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Discussion Overview

The discussion revolves around the design of a pan and tilt drive system utilizing a stepper motor, specifically focusing on achieving zero backlash in worm gearing to transmit significant torque. Participants explore various concepts and specifications related to worm drives, including torque transmission capabilities and design considerations.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant mentions the use of "scissors gears" that involve two meshing gears with spring preloading to maintain contact, though this may increase friction.
  • Another participant introduces the concept of a split worm wheel, suggesting that the preload from springs can create a differential torque, impacting the load capacity without hysteresis.
  • Questions arise regarding how to calculate the torque that can be transmitted by the split worm wheel, with a specific interest in achieving around 100 Nm in a particular application.
  • Participants discuss whether to design and build a custom worm and wheel or to purchase from a catalogue, with a preference expressed for catalogue options that ensure zero backlash.

Areas of Agreement / Disagreement

Participants express varying opinions on the methods and specifications for achieving zero backlash in worm gearing, with no consensus on the best approach or the exact torque transmission capabilities of the proposed designs.

Contextual Notes

Participants have not resolved the calculations for torque transmission or the specific design parameters needed for the worm wheel and shaft, indicating potential gaps in assumptions and definitions.

anilks
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I am designing a Pan and tilt drive for with stepper motor as prime mover. We need a zero backlash worm drive to transmit 70 Nm. motor torque is 1 Nm. What are the options.. position accuracy is 0.1 deg.

thanks
 
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I am no expert on it, but I know people use "scissors gears," where one of the meshing gears is actually two gears with a spring preloading them to contact the front-and back-side of the other gear's teeth. I suppose the preload must be large enough to prevent either side coming out of contact during maneuvers. This will cause more friction, but that may also keep the pan/tilt support from moving once it's positioned.
 
Thank you for response. I have come across split worm wheel concept while I was browsing. But what kind of Torque it can transmit (Given the PCD and no of starts). I could not figure out.
 
anilks said:
But what kind of Torque it can transmit
The two halves of the split worm wheel are preloaded by a spring or springs that generate a differential torque between the two halves. The strength of the spring determines the load that can be carried without hysteresis. If the spring is too strong then the worm and wheel will wear at a rate greater than necessary.
 
Thank you. I should have been more specific. How to calculate the torque that can be transmitted. I want to transmit about 100 N.M in a particular application. What should be the Specification of the worm wheel and shaft?

thank you .
 
anilks said:
What should be the Specification of the worm wheel and shaft?
Will you design and build your own worm and wheel, or buy from a catalogue?
 
Baluncore said:
Will you design and build your own worm and wheel, or buy from a catalogue?
I want to buy from catalogue. But looking for zero back lash
Thank you
 

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