Why is the harmonic reducer called harmonic?

Why is the harmonic gearbox called harmonic？ Firstly, let’s understand what is the harmonic drive, and then you will know the name source of the harmonic reducer. The specific process is as follows:

Harmonic drive achieves the transfer of mechanical motion by using a constructed controllable elastic deformation. The harmonic drive usually consists of three basic components, including a circular spline with internal teeth, a flexspline that produces radial elastic deformation with external teeth and one elliptical shape of wave generator with flexible rolling bearing in the external circle which is installed inside the flexspline. A wave generator with a flexible rolling bearing.

The number of external teeth of the flexspline is less than the number of internal teeth of the circular spline. When the wave generator rotates, the external teeth of the flexspline corresponding to the long axis direction just completely mesh with the internal teeth of the circular spline. While in the short axis direction, the external teeth completely disengage the internal teeth. When the circular spline is fixed and the wave generator rotates, the external teeth of the flexspline will com into or out of contact the internal teeth of the circular spline in turn. And the radial displacement of any point on the flexspline gear ring will be similar to the change of the sinusoidal waveform. Therefore, this type of transmission is called harmonic drive.

The harmonic reducer is a kind of harmonic drive device, which includes harmonic accelerator and harmonic reducer.

The harmonic gearbox mainly includes the circular spline, the flexspline and the wave generator. The three are indispensable. Among them, the teeth number of the circular spline is slightly larger than that of the flexspline.