Harmonic Drive

Product development until the end of the 80's

1955 "How did it all start?"

The principle of operation of our gears, from which the name Harmonic Drive is derived, was patented in 1955. The original patent-holder, an American company, concentrated on the manufacture of gears for highly specialised applications in aerospace.

1967 Gear Component Sets HDUC Series

In 1967 a licence agreement was signed between the American patent-holder and a Japanese company, which later traded under the name of Harmonic Drive Systems Inc. The development and manufacture of gears for universal use initially concentrated on the Gear Component Sets HDUC Series (Harmonic Drive Unit Cuptype).

1976 Flat Type Gear Component Sets HDUF/HDUR Series

In a further step, pancake-type gear sets were introduced, providing all of the advantages of Harmonic Drive gears in a flatter configuration, including compact size, light weight, simple construction, high reduction ratios in a single stage, extremely low backlash, and in-line input/output. Simple installation and maintenance were further reasons for selecting these gear sets which offered an ideal basis for further product development.

1982 Mini Servo Actuators

Further progress could be achieved by developing the highly dynamic Servo Actuators available with AC and DC technology and integrated Harmonic Drive precision gearboxes. Due to their miniature design these servo actuators are ideal for applications requiring a small envelope.

1988 IH-Type Gearing

To increase the gear life, the torsional stiffness and the torque capacity, numerous computer simulated tests and calculations had been performed to develop and launch a new tooth profile, patented as "IH type gearing". The IH tooth profile increases the region of tooth engagement greatly. For the traditional tooth profile about 15 % of the total number of teeth are in contact, whilst for the new profile up to 30 % of the teeth are in contact. The increased number of teeth in engagement results in a considerable increase in torsional stiffness.The new tooth profile also features an enlarged tooth root radius, which results in a higher allowable stress and a corresponding increase in torque capacity.