Saturday, October 19, 2019

Tooth Tips

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...

Electrical erosion is a factor to take into account when conducting a failure analysis

With the rapid advance in gear technology, new hitherto unforeseen failures can occur, and typical among them are failures due to electrical discharge. Such...

Tooth cracks are often found to be a culprit when conducting a complete failure...

Cracks originating in the surface of the tooth flank are due to Hertzian stressing at a depth relative to the maximum Hertz shear stress....

When things go wrong, conducting a detailed failure analysis is the best way to...

A gear designer must consider the most economical solution that will avoid failure within the design life. The usual result will be a gear...

Shot peening offers benefits to gears, including added strength, reduced surface fatigue

In the 11th century, every combatant carried a sword. Swords were thick and heavy to prevent breakage, making them unwieldy in battle. Those who...

As progress in the design of globoidal worm drives continues, let’s check out history,...

ISO defines a globoidal worm drive as: “A gear whose flanks are capable of line contact with those of an enveloping worm, when meshed...

The five standardized worm gear tooth forms produced by milling or grinding operations

There is a wide choice in tooth forms, each form with its own share of merits and demerits depending on the application. Several forms...

The more you know about proper lubrication, the smoother your operation will run

It has been said by Ernest Rabinowicz, professor emeritus at M.I.T., that three things terminate the life of a machine: obsolescence, accidents, and surface...
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