Harmonic Drive is the brand name of wave of wave of arts registered by the company Harmonic Drive, invented in 1957 by C.W. Musser. It is very commonly implemented in today's robotics and also used in the aerospace industry for gear reduction, but it can also be used to increase the speed of rotation or for differential gears.
The harmonics drive, which is composed of a circular spline, a wave generator and a flexspline, is a compact, light and precise torque transmission mechanism with little backlash. From these components, the flexspline is the key element for the transmission of movement. It must be flexible in the radial direction but rigid in the tangential direction to accurately convey the rotational movement. In order to satisfy this double role, the conventional flexible steel line is usually fabricated as a thin cup shape requiring a large amount of machining using special templates. Due to the thin shape of the cup, the flexible steel line produces noise and vibration when operating at high speed.
Since the double paper can not be effectively met with conventional isotropic materials, anisotropic composites have been considered. In this paper the flex section section of the flexspline was fabricated with carbon fiber epoxy composite and the tooth section with steel. The two components were then joined by adhesive bonding.
In addition, to facilitate the manufacture of the flexible steel plate and to reduce the noise and vibration of the harmonic drive, the cup and tooth sections were manufactured separately and adhesively bonded.
The static torque transmission capacities and the vibration characteristics of the flexible flexing line with adhered steel teeth and the flexible steel line with adhered steel teeth were tested experimentally. From these tests, the flexible line fabricated with adhesive bonding was found to have sufficient torque transmission capacities and both the composite flexible line and the bound steel line had better dynamic characteristics than the flexible steel line of a Conventional single piece.