Tooth Tips

The importance of anticipating heat-treatment problems in advance to avoid part failure due to...

Problems, and even failures, occurring from heat treatment are generally created by the stresses that are induced when phase transformations are taking place. During...

Electric erosion can lead to failure in wind-turbine generators, with the expected catastrophic results

My installment of this column in the August 2007 issue of Gear Solutions was devoted to electric erosion and the possible solutions. In the...

Gear-drive inspection reveals the effects of residual stresses on face contact in high-speed gear...

High-speed standards usually require verification of the mating accuracy, and that this record be maintained. This entails recording profile, lead, and pitch deviations. The...

Corrosion alone can lead to gear failure, but when you add fatigue loads and...

How many engineers know that corrosion is generally regarded as the prime cause of failures? In 1986 Batelle Labs estimated the annual cost at...

Determining the reasons for materials-based fatigue failures can be a challenge, but don’t underplay...

In the past 50 years, advances in gear technology have been driven by energy and aerospace, specifically by the gas turbine, jet engine, wind,...

Proper balance is one of the critical keys in designing and manufacturing high-speed gear...

Unbalance is the most common cause of serious vibration in high-speed gear units. When present the vibration results in bearing, tooth, and seal damage....

This conclusion of a two-part series on Hertzian fatigue modes discusses spalling and macropitting,...

Pits form from wear, electric erosion, chemical attack, thermal damage, or porosity that arises during material casting or processing. Grinding burns always lead to...

Part 1 of a discussion on Hertzian fatigue modes begins with a discussion of...

Experience has led us to rate gears by calculating their pitting resistance and bending strength. These calculations do not provide for other types of...

Robots held a place in the human imagination long before they were assigned a...

In 1921 the Czech author Karel Kapek wrote a play on the subject of mechanization gone wild titled “R.U.R.,” which stood for “Rossum’s Universal...

Part 2: Don’t compromise a quality gearbox by scrimping on seals and filters

Oil cleanliness is essential for gear unit reliability. To achieve this cleanliness in force-feed lubrication systems filters should be the last piece of equipment...

Part 1: Don’t compromise a quality gearbox by scrimping on seals and filters

The gear unit designer pays careful attention to the housing, gears, bearings, and lubrication, but quite frequently the seals and filters are an afterthought....

Understanding powder metal materials’ past will give you appreciation for current applications

Powder metal technology is older than that of cast iron. Although the use of powder metals has been in existence since 3,000 B.C., and...

Coatings are important. Here’s how they came about, and how they fit into the...

On August 12, 1902, Professor Thurston patented “a method for carrying out the process of coating one metal with another.” A further advance was...

Case depth can be considered the foundation for tooth strength

Specifications for carburized gearing of necessity pay attention to the required surface hardness. Not to be ignored, due to equal importance, is the case...

Evaluating and defining hardness, and the evolution of testing methods

Hardness is not a single, clearly defined, physically changeable value, but a complex combination of diverse concepts. In gears we need to know surface...

Part 2: Epicyclic gearing — when it works, where it doesn’t, and why that...

The application range of epicyclic gearing has now become unlimited. As an example, shuttle astronauts were required to break loose some large bolts on...

Part 1: Epicyclic gearing — when it works, where it doesn’t, and why that...

A dictionary description of epicyclic gearing is as follows: “A system of gears in which one or more gears travel around the inside or...

‘Sounds’ can be good, such as the hum of a well-designed gearbox. It’s ‘noise’...

Many seminars and papers are conducted and written under the title of “gear noise” when the full subject is sound. Sounds can be pleasant,...

Adhesive wear caused by fusing of the parts in contact, and even shearing, is...

The basis for a major part of gear research is the study of the wear phenomena, especially between two metal rubbing surfaces. Wear is...

Abrasive wear is a much more complicated condition than it first seems

A common mistake is to relate surface hardness to wear resistance. Other factors are also involved, such as ductility; the balance of free carbides...
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