ISO 281

Articles About ISO 281


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1 ISO 281:2007 - Caveat Emptor (October 2016)

I was invited by Tom Astrene of TLT to write a response to the July 2010 TLT article (Ref. 1). My rebuttal — “In Search of a Fatigue Limit: A Critique of ISO Standard 281:2007” — was published in Tribology and Lubrication Engineering, TLT, August 2010 edition (Ref. 10). While this article is also available online, I will attempt to summarize the essence of my response.

2 Not All Thin-Section Bearings Are Created Equal (February 2011)

American Bearing Manufacturers Association (ABMA) Standard 9 and ISO 281 give equations for calculating the basic dynamic radial load rating for ball bearings. These equations are based on a number of assumptions, many of which are not valid for thin-section bearings. (Thin-section bearings are described in ABMA standard 26.2.) Nevertheless, many thin-section bearing catalogs report load ratings based on these equations. Kaydon has developed a new method for calculating the dynamic radial load rating for thin-section ball bearings. The new method uses the contact stress and the number of stress-cycles-per-revolution to calculate the capacity. The new numbers are based on five years of actual test results. These equations can also be used to calculate the dynamic radial load rating for four-point contact ball bearings, which are not covered in ABMA standard 9 or ISO 281.

3 The Modified Life Rating of Rolling Bearings: A Criterion for Gearbox Design and Reliability Optimization (March 2015)

Engineers typically learn that the bearing L10 life can be estimated using the so called “C/P method” — or the “basic rating life” of the bearing, a method rooted in the 1940s. Major developments have since led to the “modified rating life,” released in ISO 281:2007, which includes the aiso life modification factor. In this paper a succession of equations used for bearing life ratings are reviewed, and current bearing life rating practices are discussed in detail. It is shown that — despite the introduction more than 30 years ago of the adjustment factor of the basic rating life, and the standardization in 2007 of the aiso modification factor — use of these improved calculation methods are not practiced by all engineers. Indeed — many continue referring to the old model as a way of seeking compliance with existing, established practices.

4 Industry News (February 2018)

The latest new hires and corporate announcements from around the industry.

5 Product News (June 2019)

The complete Product News section from the June 2019 issue of Power Transmission Engineering.

6 FEM Analysis of the Load Distribution over the Face Width of Helical Gear Pairs Considering Deviations, Misalignments and Deformations (August 2020)

The load carrying capacity of spur gears may be calculated by ISO 6336 using influence factors. The face load factor considers the impact of the non-uniform load distribution over the face width. Even if the gears had perfect geometry, the load would not distribute uniformly along the contact lines. The face load factor depends on deformations of all parts of the containing gearbox and mainly of the teeth, gears and shafts as well as on manufacturing and assembly deviations.

7 Product News (December 2020)

The complete Product News section from the December 2020 issue of Power Transmission Engineering.

8 Industry News (April 2017)

Corporate and personnel announcements from the April 2017 issue of Power Transmission Engineering.

9 Value-Driven (March 2020)

New Opportunities and Technologies Allow AC Motors to Enhance Motion Control Applications.

10 Industry News (June 2016)

News from around the industry

11 Product News (August 2011)

The complete Product News section from the August 2011 issue of Power Transmission Engineering

12 Product News (June 2010)

The complete Product News section from the June 2010 issue of Power Transmission Engineering.

13 Product News (June 2009)

The complete product news section from the June 2009 issue of Power Transmission Engineering.

14 Industry News (October 2012)

The complete Industry News section from the October 2012 issue of Power Transmission Engineering.

15 Industry News (February 2014)

The complete Industry News section from the February 2014 issue of Power Transmission Engineering.

16 Load Capacity and Efficiency of Grease-Lubricated Worm Gears (September 2014)

Varying installation requirements for worm gears, as, for example, when used in modular gear systems, can necessitate grease lubrication - especially when adequate sealing for oil lubrication would be too complex. Such worm gears are being increasingly used in outside applications such as solar power plants and slew drives. While knowledge about the operating conditions is often appropriate, the basic understanding for load capacity and efficiency under grease lubrication is quite poor. Investigations done at FZG and sponsored by FVA/AiF are shown here to give an impression of the basic factors of load capacity and efficiency. The results of the investigation indicate a satisfying quality of calculations on heat, load capacity and efficiency based on characteristic parameters of the base oil with only slight modifications to the methodology known from DIN 3996 or ISO TR 14521.

17 Evolution of Worm Gear Standards and their Consequences on Load Capacity Calculation Approach (September 2014)

Beginning with a brief summary and update of the latest advances in the calculation methods for worm gears, the author then presents the detailed approach to worm gear geometry found in the revised ISO TR 10828. With that information, and by presenting examples, these new methods are explained, as are their possibilities for addressing the geometrical particularities of worm gears and their impact upon the behavior and load capacity of a gearset under working conditions based on ISO TR 14521 — Methods B and C. The author also highlights the new possibilities offered on that basis for the further evolution of load capacity calculation of a worm gearset based on load and contact pressure distribution.

18 ISO-AGMA Standards: Specific Sliding Defined (March 2017)

Does the definition of specific sliding mean the same between ISO 21771:2007 and AGMA 917-B97? In ISO, specific sliding is the ratio of the sliding speed to the speed of a transverse profile in the direction of the tangent to the profile. In AGMA, specific sliding is ratio of gear tooth sliding velocity to its rolling velocity.