scope:

This standard provides guidelines for the design, rating and application of globoidal wormgearing mounted with axes at a 90 degree angle. This type of gearing is called double enveloping wormgearing in the United States, but the term globoidal is more commonly used worldwide.

This standard discusses the two main categories of globoidal wormgearing manufactured in industry today: the traditional Hindley designs, and the more recently developed full contact designs. The standard presents the formulas for calculating general gearset proportions for the globoidal designs and a rating procedure for Hindley designs. It does not provide a detailed or complete procedure for the design of gearsets and the cutting tools required.

Globoidal wormgearing of the Hindley design has been used in industrial applications for over 200 years. The manufacturers of Hindley wormgearing have each designed and built their own tooling to manufacture the gearing. TheHindley design uses a common base circle to form all of the tooth profiles. The worm thread is generated by a cutting edge (line) rotating in a single plane.

The more recently developed full contact designs do not use a constant base circle to form the tooth profiles. The worm thread is generated in multiple planes by a generating surface. The manufacturers of full contact gearing have each conducted their own research, and the details of their designs are proprietary to each company. This design may provide increased load carrying capability over the Hindley design, but a standard rating method for full contact designs has not been established.