Common causes of ball bearings overheating and failing

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Bearings typically overheat when they are improperly lubricated. Improper lubrication can be caused by using a low temperature grease that does not provide enough viscosity for proper operation by allowing for increased friction.  Also not re lubricating a bearing can cause it to run hotter than normal by allowing metal to rub against metal and increasing friction and rapidly causing the bearing to overheat.  Over greasing can damage a bearing as well. It may cause a seal on a bearing to crack and allow foreign particles into contact with the internal rolling components of a bearing and pit the bearing and or corrode from moisture getting in as well as allowing the grease used to lubricate the inner portion of the bearing to escape the inner compartment of the bearing.  XHYZH3X2KYV6

Below are a few pictures over overheated bearings due to improper lubrication.

 

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The facts and statistics surrounding bearing failure

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A bearing that fails is not just a random occurring event. There are always many factors as to why the bearing fails. Understanding these causes will help to understand how to prevent or significantly reduce the causes of bearing failure, so you can maximize the life of your bearing.

There are many causes of bearing failure not always can you determine the cause but most cases you can. The first and most common type is listed below.

Foreign matter: One of the most common sources of trouble in bearings is wear and pitting caused by foreign particles. This could be in the form of dirt, abrasive grit, lint, dust, steel chips, etc.  Dirt is responsible for more than 90% of all bearing troubles. Improper lubrication and contamination make up 70% of bearing failures.

Misalignment: A frequent source of trouble resulting in overheating and separator failure. Common causes are bent shafts, out-of-square shaft shoulders, out-of-square spacers, and out-of-square clamping nuts. Inspection of the raceways will show the ball track veering from one side to the other.

The next cause of bearing failure is due to improper fit of a bearing. This is characterized by one of the following conditions.

Improper mounting: Bearings should be mounted with a press fit on the rotating ring. Generally, the shaft rotates and the inner ring is mounted with a press or interference fit.

  1. Mounting bearings on shafts by applying blows or pressure to the outer race will usually cause denting (true brinell).
  2. Loose shaft fit – rotation of the shaft within the inner ring can produce heat and small loose particles of metal that will eventually get into the bearing, causing wear.
  3. Loose housing fit – damage similar to loose shaft fit.
  4. Excessive tight fits – (shaft and housing) can cause rings to crack. Usually causes excessive internal preload because of the removal of internal clearance. Causes high operating temperature and premature failure.
  5. Out of round housings – usually found in split housings where careful machining is necessary to obtain round housing. Causes localized overloading with abnormal wear on surfaces and retainer pockets. Early fatigue occurs in these areas.
  6. Poor finish on the bearing seat – a coarse finish on the bearing seat will soon break down causing a loose fit condition, previously described.

Improper Lubrication: Lack of or improper lubrication generally causes overheating or excessive wear in the bearing. These conditions can result from insufficient lubrication, improper lubricants, complete absence of lubrication, or insufficient lubrication due to loss through leakage. Also to be considered is the breakdown of lubricants either by oxidation or exposure to atmospheric conditions.

Defective Sealing: This enables foreign material and contaminants to enter the bearing, causing wear. In addition to allowing forign material (dirt) into the bearing, it also allows lubricants within and around the bearing to escape and causing the bearing to overheat and allow bearing fatigue.

High Temperatures: High temperatures frequently cause premature bearing failure, the nature of the failure being predicated on the temperature to which the bearing is raised and the grease with which it is lubricated. Mild temperature elevations may cause grease to bleed which reduces the efficiency of the lubricant. Under increasingly elevated temperature conditions, oxidation causes loss of lubricating elements and the formation of carbon. The carbon thus formed may lock or jam the bearing. High temperatures may also reduce the hardness of the metal causing early failure. High temperatures can cause loss of internal clearance and preloading results. Many bearing failures can be traced to dirt. Cleanliness is always a must!

Corrosion: The finely finished surfaces of ball and roller bearings are readily subject to corrosion by water, acids, and other agents. Corrosion is basically abrasive in nature and will account for excessive or abnormal wear in bearings. Common causes of corrosion include moisture, acid action, poor or broken down greases, poor wrappings, and condensation resulting from excessive temperature reversals.

Fatigue: Fatigue means the fatiguing of the metal in the components of the bearing. It is a result of stress reversals produced when rotating members create flexing of the metal. Fatigue develops due to the magnitude of the load and the number of times it is repeated. Actually, the rolling elements create a wave of metal in front of them as they roll. Thus, the metal in the components is alternately put in tension and then compression. This action eventually results in flaking of the metal.

Vibration Brinell (False Brinell): Caused by the rapid movement of the balls in the raceway while the equipment is idle. Rolling elements quickly remove lubrication and, because there is not enough rotation of the bearing, fresh lubricant is not moved back into the spot. This means the bearing is sitting in one spot, devoid of lubrication, and the movement of the rolling elements wears away the metal. The indentations run axially across the races.

Electrical Damage (Fluting): When electric currents pass through a bearing, there is arcing and burning at the points between the races and the rolling elements where the current jumps the air gap. Pitting or cratering of a bearing is caused by relatively large charges of electricity.

Storage: Dampness (rust) – store bearings in a dry room. If you see rust on a bearing, you should not use the bearing. Corrosion is abrasive and will cause premature bearing failure.

Unwrapping: Not sure of bearing numbers, tearing wrappings and boxes – lets in dirt, corrosion, etc. Always take bearing to the place of installation before unwrapping. This keeps the bearing clean. Make sure parts are clean. If the bearing and parts are to be left out, cover to keep them clean.
Buying Bearings:  Bearings for most any application can be bought nearly anywhere but here at Wildwest Bearings we take utmost care of inventory and keep in dry secure location and take the time packaging them to make sure they arrive safe and ready for use by you!  We also only carry quality bearings made out of the highest quality materials.
Visit our store at http://www.wildwestbearings.com/bearingstore  or call toll free:
1-866-584-8682 to get a quote!
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History of Bearings

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Hundreds of years ago, when man lacked strength and endurance to carry loads, such heavy loads to be transported were put on simple skids and dragged to the place of destination. Dragging heavy loads on dry ground requires considerable force. These forces can be reduced by using lubricants between the sledge runners and the ground. This lubricant-probably water – was poured to reduce the friction and thereby reducing the volume of force. As the time passed on, these forces were further reduced when man learnt to insert wooden rollers between the ground and the object. THUS SLIDING MOTION WAS CONVERTED INTO ROLLING MOTION, which is the basic principle of  the bearing. However, things weren’t developed much for years, till the concept of BALL was conceived, as the application of rollers was not practical everywhere.

In the 17th century, stone balls were produced and were in used for variety of applications to minimize the friction. Since the stone balls were not suitable for many applications, cast iron balls were also produced, but that was also not suitable. In the 19th century, the concept of steel balls was conceived and steel balls were produced. During this era, on lathe machines, balls of remarkable accuracy were cut off from a steel rod and the ends were machined to form a sphere. At the end of the 19th century, balls manufactured by this method in England were within the tolerance of 0.025 to 0.050 mm.The first practical caged-roller bearing was invented in the mid-1740s by horologist John Harrison for his H3 marine timekeeper. This uses the bearing for a very limited oscillating motion but Harrison also used a similar bearing in a truly rotary application in a contemporaneous regulator clock.  A patent on ball bearings, reportedly the first, was awarded to Jules Suriray, a Parisian bicycle mechanic, on 3 August 1869. The bearings were then fitted to the winning bicycle ridden byJames Moore in the world’s first bicycle road race, Paris-Rouen, in November 1869. In the year 1883, Friedric Fischer, an instrument maker in Scheweinfurt – W. Germany, after numerous experiments, developed a method of grinding wheel balls, turned between the centers on the centre less principle. For this purpose, he designed ball grinding machine called “BALL MILL”..  The modern, self-aligning design of ball bearing is attributed to Sven Wingquist of the SKF ball-bearing manufacturer in 1907, when he was awarded Swedish patent No. 25406 on its design. Henry Timken, a 19th century visionary and innovator in carriage manufacturing, patented the tapered roller bearing in 1898. The following year he formed a company to produce his innovation. Over a century later the company has grown to make bearings of all types, including specialty steel and an array of related products and services.

In the early 1980s, Pacific Bearing’s founder, Robert Schroeder, invented the first bi-material plain bearing which was size interchangeable with linear ball bearings. This bearing had a metal shell (aluminum, steel or stainless steel) and a layer of Teflon-based material connected by a thin adhesive layer. Today ball and roller bearings are used in many applications which include a rotating component. Examples include ultra high speed bearings in dental drills, aerospace bearings in the Mars Rover, gearbox and wheel bearings on automobiles, flexure bearings in optical alignment systems and bicycle wheel hubs and nearly every other application imaginable.

Just as man has come a long ways since the early days, so has the evolution of the bearing.  As time passes we have developed many different styles of bearings more suitable for certain applications than other types of bearings.  We have also found better materials than stone or wood to make a bearing that can handle the forces that the applications each require. As our world evolves so do the bearings needed for each specific application and as new products become available you can be sure to find out about it here!
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Our blog has changed to reflect our new domain name and all our content will be published here at http://www.wildwestbearings.com/blog from here forward!

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What is a ball bearing and what is its purpose?

Have you ever wondered what is the difference in bearings?  Well if you have today I’ll give you some insight about what a ball bearing is, and how it can make your life easier!  Ball Bearings are a type of rolling-element bearing that uses balls to maintain the separation between the bearing race.  The mechanical purpose of a radial bearing is to reduce rotational friction, and support radial and axial load. A ball bearing achieves this by using at least two races to contain the balls and distribute the loads through the balls. In most applications, one race is stationary and the other is attached to the rotating assembly (such as a hub or shaft). As one of the bearing races rotates, it causes the balls to rotate as well. Because the balls are rolling they have a much lower friction than if two flat surfaces were sliding against each other.
Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area between the balls and races. However, they can tolerate some misalignment of the inner and outer races.

Common Elements/Compounds used to manufacture a ball bearing


There are several common designs of ball bearing, each offering various trade-offs. They can be made from many different materials, including: stainless steel, chrome steel, and ceramic (silicon nitride (Si3N4)). A hybrid ball bearing is a bearing with ceramic balls and races of metal.

Common ball bearing designs

Angular contact

An angular contact ball bearing uses axially asymmetric races. An axial load passes in a straight line through the bearing, whereas a radial load takes an oblique path that tends to want to separate the races axially. So the angle of contact on the inner race is the same as that on the outer race. Angular contact bearings better support “combined loads” (loading in both the radial and axial directions) and the contact angle of the bearing should be matched to the relative proportions of each. The larger the contact angle (typically in the range 10 to 45 degrees), the higher the axial load supported, but the lower the radial load. In high speed applications, such as turbines, jet engines, and dentistry equipment, the centrifugal forces generated by the balls changes the contact angle at the inner and outer race. Ceramics such as silicon nitride are now regularly used in such applications due to their low density (40% of steel). These materials significantly reduce centrifugal force and function well in high temperature environments. They also tend to wear in a similar way to steel bearing, rather than cracking or shattering like glass or porcelain.
Most bicycles use angular-contact bearings in the headsets because the forces on these bearings are in both the radial and axial direction.

Axial

The design of axial ball bearings is intended solely to operate with considerable axial load, any radial load is unacceptable for them. Axial ball bearings can accommodate axial loads in one direction only.
As a rule, one of the bearing washers is produced tight to fit on the shaft and the others are loose to be installed in the housing.  Axial ball bearings with flat loose washer do not allow any, even slight, angular misalignment between the shaft and the housing. If it is necessary to provide unit operation with initial angular misalignment, bearings with loose sphered seat washers should be used. Usually  axial ball bearings are produced split, which simplifies their mounting. Some special applications have stamped protective shield, which makes the whole construction undetachable.
Axial ball bearings are produced with pressed steel cages, with machined cages of brass, steel, aluminum alloys or glass fiber reinforced polyamide.
An axial ball bearing uses side-by-side races. An axial load is transmitted directly through the bearing, while a radial load is poorly supported and tends to separate the races, so that a larger radial load is likely to damage the bearing.

Deep-groove

In a deep-groove radial bearing, the race dimensions are close to the dimensions of the balls that run in it. Deep-groove bearings can support higher loads. This style is typically used in precision instruments, low noise motor, automobiles, and motorcycles.

Friday, March 23, 2012

Lonestar Bearings is now Wildwest Bearings and our online store has changed for the better!

It was recently decided that it is in my business’s best interest to change from our previous website business name from Lonestar Bearings to Wildwest Bearings. We have also changed our webstore link to http://wildwestbearings.com/bearingstore this new layout will allow us to better organize our catalog and streamline our customer experience and gives you the ability to share products with your friends to your favorite social media with a simple click of a button!!! We are adding more products to our webstore. We have added several special ag bearings, radial bearings, tapered bearings, disc harrow bearings and tapered bearing sets.  We welcome your input on how we can improve our website check back often as we are adding new products all the time!!!
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