In Transmission line two main parameters in any mechanisms are the Torque and Speed for Circular, Linear motions. Considering the circular motion elements like Gears, Belts, Chains, Ropes, Screws are the conventional components are being used.

Taking in account Gear systems are the major and efficient power transmission elements for defined center distances and in the gearing system backlash is one of the major disadvantage  as far as in traditional gearing approach.


While discussing about gears, the backlash is the gap between two mating gear’s teeth profiles, but this micro clearance is essential for smooth running of mating gears without rotational arrest, However, this clearance also has disadvantages such as motion loss, positional errors, efficiency drop, vibration and noise, wear.

Zero Backlash:

In order to achieve the zero backlash(no gaps between teeth) standard methodology is pre-tensioning of engaged gears but this too have few negative impact on the whole drive system. Hence there was a technology developed called Harmonic Drive Gear (also known as Strain Wave Gears) is a standard transmission component used in High Precision, Repeatability and less space high reduction ratio applications.

Technology and Mechanism:

The Strain wave gearing system is a very unique technology which transmits high torque through an elastically deformable part.

This gearing system base components are

  1. Circular Spline – Fixed cylindrical part with internal gear teeth cut
  2. Flexible Spline – Non-rigid cylindrical part with external gear teeth cut
  3. Wave generator – Consists Of ball bearing fit in to a ball bearing fitted on elliptical plug


  1. High Torque with lesser mass ratio
  2. High positioning accuracy and repeatability
  3. Increased torsional stiffness
  4. Very low friction and wear accordingly
  5. Smooth and Noise, Vibration reduced operations
  6. Reduced weight gearing system


  1. Robotics
  2. Semi-conductor manufacturing equipment
  3. Space Vehicles
  4. Security applications
  5. Factory Automation equipment
  6. Medical Diagnostics and Surgical robotics
  7. Testing & Research

We at Sunstream have been engaged with different domain clients such as Medical, Semi-conductor, Industrial Equipment and Automation machinery from requirement study, Concept generation Design, Prototyping, Validation until Commercial release of documents to operations. We support on various machine elements design, sizing, simulation like in the precision technology of Harmonic Drive Gears. Sunstream’s engineering design, 3D modeling services and Analysis support are integral part of our offering in the mechanical design space.