What is SMD Harmonic Gearbox?

2 min readFeb 4, 2022

Harmonic gearbox is also known as Strain Wave gearbox is a mechanical gearing system that uses flexible spline with external teeth which is made by rotating elliptical plug to engage with the internal gear teeth of an outer spline. The Harmonic Gearbox was first invented by Harmonic Drive, Germany and they have manufactured first series under these type. Strain Wave Gearing is mainly used in Robotics and Aerospace.

SMD Harmonic Gearbox SCSG and SSHG series.
Two types of SMD Harmonic Gearbox

Harmonic Gearbox Mechanism?

Harmonic gearbox consist of mainly 3 parts i.e. Wave Generator, Flex Spline, Circular Spline. A Circular Spline has teeth on its inside. The flex spline and wave generator are placed inside the circular spline, meshing the teeth of the flex spline and the circular spline.As the Wave generator plug rotates the flex spline which are connected with circular spline slowly changes their position.

For a strain wave gearing mechanism, the gearing reduction ratio can be calculated from the number of teeth on each gear, in a similar manner to a cycloidal drive:

R = flex spline teeth — circular spline teeth/Flex spline teeth

SMD Gearbox Structure

Advantages of SMD Harmonic Gearbox?

1) Nominal torque — 21Nm to 180Nm.

2) Temprature Range — -40ᵒc to +150ᵒc.

3) Coatings — Anti Rust = Electro less plating.

4) Mounting — Suitable Motor Adaptor.

5) IP Protection Class — Can be increased to IP65.

6) Available reduction ratio -1:50,1:80 1:100, 1:120

7) Highly rigid for stable precision work.

8) Compact and higher accurate.

9) Short axial dimension.

Advantages of SMD Harmonic Gearbox?

1) Industrial robots

2) Aerospace

3) Medical Equipment.

4) Machine Tools.

5) Measuring and Testing.

6) Printing Machine.

7) Special Purpose Machine.

8) Semiconductor Equipment’s etc.

View this Video for SMD Gearbox Application -

For More Information Visit,

Website — https://www.smdgearbox.com/products

Mail id — sales@smdgearbox.com

Phone No- 7030669818




Our Company Name SMD stands for SEIMITSU MOTION DRIVES as a trailblazer in the solution provider of various types of industrial Gearbox in Taiwan.