The life of a bearing is usually defined as the number of revolutions at which it can operate without failure. For example, a bearing with a life rating of 30,000 revolutions (30K) can operate for 30,000 rotations before failure occurs.
The life rating is determined by the application and operating conditions (e.g., speed, load). The most important factor affecting the life of a bearing is its operating temperature; when the temperature rises above its design range, the service life of the bearing will be significantly reduced. Therefore, it is important to select an appropriate lubricant for each application to ensure that it operates within its design temperature range.
The life of the bearing is limited.
The life of the bearing is limited. It depends on the load, speed and lubrication conditions.
The life of a ball bearing is between 30,000 and 1,000,000 revolutions.
Ball bearings have a limited lifespan due to wear or breakage. The life of a ball bearing can be increased by using higher quality materials and better manufacturing techniques.
Lubricants affect bearing life.
The lubricant used in a bearing system can have a significant impact on the life of the bearings. The type of lubricant and its properties, such as viscosity, will determine how well the lubricant performs.
Lubricants are classified according to their chemical composition and physical properties. Lubricants are divided into two categories: water-base and oil-base. Water-base lubricants include vegetable oils, linseed oil, castor oil and animal tallow. They have relatively low viscosities at room temperature and improve with heat. Oil-base lubricants include petroleum distillates (mineral oil), synthetic hydrocarbon oils, vegetable oils and animal fats that have been hydrogenated or partially hydrogenated to improve their viscosity at lower temperatures.
The performance of a bearing depends on the quality of its environment during operation, which includes factors such as temperature, humidity, dirtiness and contamination by other materials. These factors can affect both the structure and performance of the lubricating film between surfaces in contact with one another during operation.
Bearing material affects bearing life.
The most important factor that determines the life of the bearing is the quality and type of material used for the rolling elements. There are two main types of rolling element materials: steel and ceramics.
Steel has been used for decades as the standard material for bearings because it is inexpensive, readily available, and easy to machine. However, there are some disadvantages associated with using steel as a bearing material. If steel is exposed to high temperatures or corrosive environments, it can cause premature failure of the bearing due to corrosion or oxidation (rusting). Also, because steel is softer than other materials, such as ceramics, its surface becomes worn more quickly during use and this results in less surface area contact between the balls or rollers and raceways which reduces load carrying capacity and increases friction losses.
Ceramics are harder than steel and have superior lubrication properties which make them ideal for applications where extreme temperatures or high speeds exist such as jet engines or wind turbines where temperature may exceed 1,200°F (650°C). Ceramic bearings are also used in harsh environments such as mining equipment where they must withstand high pressure loads while operating at high speed and temperature.
Bearing contamination can affect bearing life.
The main factors that affect bearing life are lubricant quality and contamination. Contamination is one of the major causes of premature failure of bearings.
Contamination can be defined as foreign matter in a medium, such as oil or air, which reduces the quality of that medium. The presence of contamination in moving parts can cause problems due to friction, heat generation and corrosion.
Bearing contamination can be classified into two types:
Internal contamination: This type of contamination occurs inside the bearing itself (e.g., pitting). It’s caused by a combination of factors including overheating, overloading and lack of lubrication. This type of bearing failure will usually result in total failure within weeks or months rather than years.
External contamination: This type of contamination occurs outside the bearing but still impacts its performance (e.g., oxidation). External contaminants are harder to control but shouldn’t pose an immediate threat to your bearings’ health.
The operating environment of the bearing affects the bearing life.
The following are some examples:
1. The operating temperature and ambient temperature. Higher operating temperatures shorten the bearing service life, while lower temperatures extend its life.
2. The load and speed. High load and speed increase friction in the bearings, which shortens their service lives.
3. The direction of rotation. Some bearings have different service lives in clockwise and counterclockwise directions of rotation; others have different lives depending on whether they rotate in one direction only or in both directions; still others have equal lives regardless of direction of rotation (such as ball bearings).
4. Corrosion protection measures taken during installation, such as grease lubrication or environmental protection measures such as dustproof coverings or oil seals etc., affect bearing service life by protecting them from corrosion or contamination by dust or water etc..
Regular maintenance and lubrication can extend bearing life.
Bearing maintenance is an important part of the overall machine maintenance program. Most manufacturers recommend that bearings be inspected and lubricated regularly. Inadequate or improper lubrication can lead to premature failure of bearings.
The proper lubricant should be used for each application. Oil-lubricated bearing systems should use oil, grease-lubricated systems should use grease and dry systems should use special non-oily lubricants.
Bearings should be cleaned with a solvent that is suitable for the type of bearing material being used. For example, nylon and nylon-graphite bearings require a specific solvent that will not cause damage to these materials. After cleaning, clean oil or grease (or other appropriate lubricant) must be applied to reseat the ball/roller/bushing contacts in the housing bore(s). The amount of lubricant used depends on how much surface area must be covered by the lubricant film so that it will flow into all areas under load where contact between moving parts takes place. This amount varies depending on how dirty or worn the bearing is when it is removed from service for inspection and maintenance work.
All sealed bearings have a limited life span, the question is how long do they last and how we can determine when it’s time to change them. There are a few factors that will contribute to the end of bearing life, some are mechanical and others are based on the running environment.