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. The Hindley 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.
Types of reducers
This standard provides information pertaining to globoidal wormgear speed reducers of the following specific types:
The velocity factor table in this standard provides data for sliding velocities up to 6000 feet per minute. For velocities in excess of 6000 feet per minute, the manufacturer should be consulted.
Where the sliding velocity of the worm thread exceeds 2000 feet per minute, additional consideration must be given to the lubrication of gears and bearings. Special lubricants and a pressurized lubrication system may be required.
The input power formulas for globoidal wormgearing apply for ratios of 3:1 and greater. Engineering practice dictates that ratios in excess of 74:1 should be discussed with the manufacturer.
Wildhaber plane enveloping globoidal gearing is not covered in this standard.
This standard does not pertain to globoidal wormgearing used as speed increasers. For such applications, the manufacturer should be consulted.
The equations and values presented provide a general approach to design and rating. Deviations from the methods and values stated in this manual may be made when justified by experience, testing or more specific analysis. It is intended for use by experienced gear designers capable of selecting reasonable values based on their knowledge of the performance of similar designs and the effect of such items as lubrication, deflection, manufacturing tolerances, metallurgy, residual stresses and system dynamics. It is not intended for use by the engineering public at large.
The following standards contain provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below.
[The foreword, footnotes and annexes, if any, in this document are provided for informational purposes only and are not to be construed as a part of ANSI/AGMA Standard 6035-A02, Design, Rating and Application of Industrial Globoidal Wormgearing.]
This standard revises, combines and supersedes two previous independent standards: ANSI/AGMA 6030-C87, Design of Industrial Double-Enveloping Wormgears, and ANSI/AGMA 6017-E86, Rating and Application of Single and Multiple Reduction Double-Enveloping Worm and Helical-Worm Speed Reducers. It presents guidelines and practices for the design, rating and application for industrial globoidal wormgearing.
The first draft of ANSI/AGMA 6035-A02 was made in December 2000. It was approved by the AGMA membership in October, 2001. It was approved as an American National Standard on March 20, 2003.
Suggestions for improvement of this standard will be welcome. They should be sent to the American Gear Manufacturers Association, 500 Montgomery Street, Suite 350, Alexandria, Virginia 22314.
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