Polyurethanefoam

P = Combined Load (Dynamic Equivalent Load) X = Radial load factor Y = Axial load factor Fr = Radial load Fa = Axial load

Silicone rubber, or polysiloxane, is available in both solid and liquid forms and is one of the very few rubber types that are both biocompatible and hypoallergenic. This rubber type is also resistant to many chemicals, extreme temperatures, fire, and ultraviolet (UV) radiation while offering superior malleability.

Nitrile rubber is used in many automotive applications and in the aviation and aerospace industries due to its resistance to gasoline damage. It is also used to create latex-free surgical gloves.

Ispolyurethane rubberor plastic

L10h = Basic rating life in hours P = Dynamic equivalent load C = Basic dynamic load rating n = Rotational speed p = 3 for ball bearings or 10/3 for roller bearings

As you can see from the equation above, in order to determine the L10 life of a specific bearing the application radial and axial loads are needed as well as the application rotational speed (RPM’s). The actual application loading information is combined with the bearing load ratings to identify the combined load or Dynamic equivalent load that is needed to complete the life calculation.

Polyurethane RubberSheet

Nitrile rubber, or Buna-N, is a type of synthetic rubber that is resistant to heat, gasoline, and many types of oil, including mineral and vegetable oils. This rubber type is also resilient and resistant to tensile set, which means it rebounds back to its original shape easily after being stretched.

Natural rubber, also called isoprene rubber, is created from the liquid latex, or milky liquid sap, of the Hevea brasiliensis tree. This rubber type is extremely flexible, elastic, durable, and resistant to damage that can be inflicted on some rubbers by extreme temperatures. Natural rubber is also abrasion-resistant and has high tear- and tensile-strength, which is a term used to describe how resistant the material is to breaking when under extreme tension.

However, this synthetic rubber type can be rather costly, so keep this fact in mind when selecting the rubber type for your unique application.

Polyurethanevsrubbersole

However, natural rubber is prone to degradation over time when used in outdoor applications where it will be exposed to sunlight and heat. In addition, isoprene rubber is not the best option when creating products that will be exposed to caustic chemicals, including petrochemicals, on a regular basis because frequent exposure to these chemicals can damage the rubber.

Neoprene is one of the oldest types of synthetic rubber. Also called chloroprene or polychloroprene, this rubber type is very corrosion- and heat-resistant. Also, unlike natural rubber, this synthetic rubber is a good option for outdoor applications due to its resistance to sunlight and the oxidation sunlight can cause. Neoprene also has a high tensile strength and is resistant to many types of chemicals, including petrochemicals.

Polyurethanevsrubberbushings

EPDM is often used to create roofing, outdoor hoses, and weatherstripping. It is also used as a sealant in the automotive industry.

Polyurethane rubberuses

However, EPDM rubber has a slightly lower tensile strength than neoprene rubber and can break down over time when exposed to petroleum products, such as mineral oil and some other lubricants. In addition, EPDM produced with a substance called carbon black can conduct electricity, so keep this fact in mind when considering this rubber for your application.

Now that we have a good understanding of how to calculate the basic fatigue life and expectancy of rolling bearings, let’s focus on other factors that determine life expectancy. Natural wear and tear are the most common cause of bearing breakdown, but bearings can also prematurely fail due to extreme temperatures, cracks, lack of lubrication or damage to the seals or cage. This type of bearing damage is often the result of selecting the wrong bearings, inaccuracies in the design of the surrounding components, incorrect installation or lack of maintenance & proper lubrication.

Bearing life is mostly often measured using an L10 or L10h calculation. The calculation is basically a statistical variation of individual bearing lives. A bearing’s L10 life as defined by ISO and ABMA standards is based on the life that 90% of a large group of identical bearings will attain or exceed. In a nutshell, a calculation on how long 90% of the bearings will last in a given application.

However, this rubber type can be more costly than other synthetic rubber options and does not have good resistance against damage that can be inflicted by some chemicals, such as ketones and aldehydes.

EPDM vsPolyurethane

Polyurethanevsrubberwheels

Bartlett Bearing can help you! We inventory a complete line of factory authorized products geared to the electric motor repair industry. Expertise, experience, inventory and quality brands allow us the capability to service repair facilities nationally.

Silicone rubber is widely used in the medical industry due to its biocompatibility. It is also used to create food containers, cookware, cooking utensils, and baby care items.

Styrene-butadiene rubber (SBR) is a very affordable synthetic rubber that is known for is extreme hardness and durability. This rubber type also has high tensile strength and is abrasion-resistant. Since SBR has many of the characteristics of natural rubber, it can be used as a natural rubber alternative in some instances.

At Bartlett Bearing Company, our associates frequently field questions from our customer base asking for a bearing with a specific life rating of “X” amount of hours or revolutions. This is often a very difficult question to answer unless all the required application details are provided. But even then, it is almost impossible to completely predict bearing fatigue.

Cast polyurethanes are produced by mixing two liquid components, polyol and isocyanate. After they are mixed at a specific ratio, they are poured into a mold. The mixture will cure and become hard. After it is cured, it can be removed from the tooling. Polyurethane can be made in a variety of densities and durameters by varying the isocyanate, polyol, or additives.

Ethylene propylene diene monomer (EPDM) rubber is another synthetic rubber option that offers many of the characteristics of neoprene rubber at a slightly lower cost. This rubber type is also a great option for outdoor applications due to its resistance to extreme temperatures, sunlight, corrosion, and overall degradation when exposed to outdoor elements.

Notice that the L10 Life Calculation does not consider temperature, lubrication and a host of other key factors crucial to achieving the designed application bearing life. Proper treatment, handling, maintenance and installation are all simply assumed. This is why it is extremely difficult to predict bearing fatigue and why less than 10% of bearings ever meet or exceed their calculated fatigue life.

However, neoprene is slightly more costly than many other types of synthetic rubber and is not immune to damage from all chemicals.