Posted by Bradley Irwin on March 4, 2016
Bearings are an essential part of machinery design. They make movement possible and keep different parts from damaging each other.
The pillow block bearing
is a particularly useful piece of equipment that makes it possible to join rotating and stationary parts together.
Pillow Block Bearings – Form And Function
A pillow block bearing is a piece of equipment designed to secure a rotating shaft to a stationary surface.
The inner sleeve of the bearing turns along with the shaft, while the outer sleeve is anchored to the surface.
The two sleeves are separated by the bearings themselves, minimizing friction between the two parts. This provides structural support to the shaft without impeding its rotation.
Pillow block bearings have a wide range of applications in industrial, manufacturing, and transportation applications.
The bearings inside a pillow block can be made from many different materials in many different forms. Ordinary ball bearings are common, as are roller bearings. Some blocks even use powdered metal or all-liquid bearings.
Different Types of Pillow Block Bearings
While the term “plummer block” is typically used synonymously with pillow block, it actually refers to a heavier-duty piece of equipment.
Plummer blocks are heavily reinforced and sealed to protect their bearings from harsh environments.
Plummer block bearings are used in the most demanding applications to minimize the possibility of failure. These extra-tough blocks are also usually sold without bearings so that the end user can add the most suitable form of bearing prior to installation.
Another major distinction between kinds of pillow blocks is between split and unsplit blocks.
As the name implies, a split block is a two-piece fitting where the external half of the block can be removed from the half anchored to the surface.
This allows the bearings (and even potentially the shaft) to be inspected, maintained, or replaced without removing the block from its anchorage.
Unsplit blocks come as a single unit. Their bearings are generally not designed to be serviced.
Operation And Maintenance
When pillow blocks are chosen correctly for the application where they’re used, they’re normally extremely reliable.
Many light-duty pillow block bearings are designed to be replaced rather than maintained. Heavier blocks intended for heavier loads — or more critical functions — tend to be over-engineered and designed with maintenance in mind.
By far the most common form of maintenance required for pillow block bearings is lubrication.
Although some lighter bearings are intended to lubricate themselves (or even function without lubrication), regular applications of fresh lubricant are required in most blocks subjected to significant loads.
Different blocks are designed to use liquid oils, thick greases, or powdered lubricants. These are generally applied through a lubrication port built into the block itself.
The pillow block bearing plays a humble, but important, role in countless different pieces of machinery and equipment. When designed properly, chosen wisely, and used according to their limitations they can be relied on to give years of trouble-free service.