Archive for July, 2013

About Bearing Housings

Friday, July 26th, 2013

A bearing housing, also called plummer block or pillow block, refers to a pedestal which is utilized as a support to a rotating shaft along with compatible bearings & other accessories. Materials for a bearing housing is usually made of cast iron or cast steel.

Pillow blocks are housings that have a bearing fitted into them. That said, the user doesn’t have to buy the bearings separately. Pillow blocks are typically mounted in cleaner environments. Usually, they are intended for lesser loads of general industry.

It is what sets them apart from “plummer blocks”. These are bearing housings supplied without any bearings and are intended for higher load ratings and corrosive industrial environments for the most part. However, the terms plummer block and pillow block are used interchangeably in certain places in the world.

The basic application of these two types is the same which is to mount bearings, thus safely enabling their outer ring to be stationary and at the same time allowing rotation of the inner ring. The housing is bolted to a foundation through the holes in the base.

Bearing housings could either be split type or unsplit type. Split type housings refer to two piece housings in which you can detach the cap and base, whereas certain series are one single piece housings. Different seals are provided so as to keep dust and some other contaminants from entering the housing. That being said, the housing gives a clean environment for the expensive bearings so they can freely rotate, thus increasing their performance and duty cycle.

Bearing housings are typically composed of grey cast iron, but different grades of metals may be used to come up with the same.

Is synthetic oil lubrication recommended for tapered roller bearings?

Friday, July 19th, 2013

Q: Do you recommend synthetic oil lubrication for tapered roller bearings? 

A: The usage of synthetic lubricants with tapered roller bearings is generally OK, assuming the lubrication has the right additives for your specific application requirements. There are cases wherein synthetic greases are superior to petroleum-based oils when it comes to their capacity to fight breakdown from mechanical and thermal conditions.

Nevertheless, it is good advice to always consult the original equipment manufacturer in regards to any change from a lubricant that is specified by them. Before you opt for synthetic oil grease for your application, touch base with your sales or service engineer so you can rest assured it is acceptable in your application.

How to Replace Boat Trailer Bearings and Bearing Protectors

Friday, July 12th, 2013

Trailer bearing protectors refer to the spring-loaded metal caps which replace the dust caps on a trailer’s hubs. This holds particularly true when it comes to boat trailers that enter the water when the boat is launched.

These protectors prevent dirt and water from coming in contact with the trailer bearings and they keep grease inside the hub, even when submerged. Trailer bearing protectors contain a spring inside to keep stable and constant pressure on the trailer bearings in any condition, be it wet or dry.

Watch this video and learn how to replace boat trailer bearings and bearing protectors.


About Bearing Lubrication

Monday, July 8th, 2013

When a bearing runs under extreme conditions, the lubricant selection is vital. Lubrication will have a huge impact on life, torque, speed, noise, grease migration, out-gassing, temperature and rust prevention of the bearing.

The two main types of lubricants are oil and grease. Oil is the main lubricant used for ball bearings. In the past, the majority of lubricating oil was refined from petroleum. In this day and age, synthetic oils like diesters, silicone polymers, and fluorinated compounds have become commonplace.

On the other hand, grease is an oil where a thickener has been added to in order to keep oil from migrating away from the lubrication site. It is utilized in cases where frequent replenishment of the lubricant is impossible or undesirable. The operative properties of grease rely heavily upon the base oil. Other elements being identical, grease usage instead of oil yields higher starting and running torque and can limit the bearing to lower speeds.

Petroleum Mineral Lubricants

Petroleum lubricants are known for their outstanding load carrying abilities and are excellent against corrosion. However, they are useable only at moderate temperature ranges (-25º to 250 ºF). They’re suggested for use at moderate temperatures, light to heavy loads and moderate to high speeds.

Super-Refined Petroleum Lubricants

This type of lubricants may be usable at higher temperatures as compared to petroleum oils (-65 º to 350 ºF), but they still display the same excellent load carrying capacity.

Synthetic Lubricants

The esters, diesters and poly-a-olefins are among the most widely used synthetic lubricants. They may not have the film strength of a petroleum product, but they have a wide temperature range (-65º to 350 ºF) and are oxidation resistant.

Silicone Lubricants

Silicone products are typically used over a much wider temperature range (-100 º to 400 ºF), but they happen to not have the load carrying capacity of the petroleum types and other synthetics.

Perfluorinated Polyether (PFPE)

These types of oils and greases are widely used where stability at extremely high temperatures and/or chemical inertness is deemed necessary. This specialty lubricant possesses remarkable load carrying capacities. However, its inertness makes it less compatible to additives, and less corrosion resistant.