Bears Limited

Bears Limited

What are Journal Bearings?

A journal bearing is a little different than your average bearing variations of roller, ball and thrust. So what is it? A journal bearing by definition is a simple bearing in which a shaft or ‘journal’ rotates in the bearing with a layer of lubricant separating the two parts. All bearings purpose is to lower the friction between two moving parts using a lubricant such as oil. Journal bearings are used for this purpose as well and are commonly found in industrial machinery with high horsepower and high loads, such as steam turbines, centrifugal compressors, pumps and motors.

Journal bearings are different because there is no rolling element which is usually found in most bearings. Journal bearings are often called plain bearings because they are considered to be relatively simple but the theory behind them can be quite complicated.

The general theory behind a journal bearing is that as one surface moves, it drags the lubricant into the gap that is made between it and the other. As the lubricant moves forward, the space decreases. The lubricant generates pressure. This pressure prevents the lubricant from entering the gap created. The lubricant within the gap reaches a pressure limit after which it pushes the lubricant through the smaller space.

The Different Types of Journal Bearings

As with any variation bearing there are many different types within that heading. This is the same for Journal Bearings; there are many different types of journal bearings such as pins and bushings, dry and semi-lubricated journal bearings, and tilting-pad bearings. Here is a brief look at some of the different journal bearings available:

Dry Journal Bearings – this type of journal bearing consists of a shaft rotating in a dry sleeve which is often blended with solids such as graphite. They are limited to low loads and low surface applications.

Low Speed Pins and Bushings Bearings – this type of journal bearing is used when the shaft or shell does not make a full rotation, is at a low speed, and usually turns direction and reverses. Many outdoor and mining applications use these types of journal bearings.    

Tilting Pad Bearings – this type of journal bearing consists of a partial arc design. The pads are used to pivot and tilt dependent on the load movement on the lubricant and shaft. The different amount of pads depends on the load amounts, the higher the load the more pads are used.

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Bearings

What is the value of a Mary Meyer Grandma's teddy bear limited edition cert. # 1372 out of 3500?

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