Generally, all types of machinery are provided with sup […]
Generally, all types of machinery are provided with supports for rotating shafts, the supporting device is known as a bearing. In other words, a bearing is a machine element that constrains relative motions and used to reduce the friction between moving parts.
Bearing employs to support, guide and restrain moving the element. This is a stationary member and it carries the load.
The part of the shaft supports by the bearing is known as the journal which is a moving member. Bearings are classified according to the type of operation they do.
The motions allowed, or
to the directions of the loads or forces applied to the parts.
Types of Bearing
Following are the most commonly used types of bearing.
Thrust BearingFoot Step Bearing
Rolling contact or Anti-friction BearingBall and Roller Bearings
1. Bush Bearings
The simplest type of bush bearing shown in the figure. it consists of a cast iron bearing block and a brass or gunmetal bush. In these types of bearing, The base plate of the bearing block provides with holes for bolting down the bearing in position.
At the top of the bearing, there is a counterboring oil hole that passes through the block and bush in facilitating lubrication of the shaft and the bush.
It is using for the shaft which carry light loads and which rotate at slow speeds. In this type of solid bearing, the shaft may introduce and removed wisely.
2. Plummer Block
When a long shaft requires to support at intermediate point a pedestal bearing or more Plummer block is put to use.
It consists of:
A cast-iron pedestal or blocks with a sole,
Tow split gum metal or bushes,
A cast-iron cap and tow square-headed bolts for fastening the cap and the block together.
A projecting snug in the bottom bush, fitting in the corresponding hole in the body or block, prevent their rotation. The bush is preventing from moving along the length of the shaft by two collars at the sides. It is made of two halves to help.
Placing and removal of the shaft in and from the bearing.
Change for wear in the bushes, and
Renewal of the bushes.
In a bush bearing. there is a rubbing action between the outer surface of the shaft and the inner surface of the bearing. And the resulting friction minimizes by the presence of a film of lubrication oil.
For line shafting, ring oiling may consider the safest and most efficient type under the ordinary condition of service.
3. Thrust Bearings
In thurst bearing, the bearing pressure will be axial. The axis of the shaft may vertical or horizontal.
If the axis of the shaft is vertical, the thrust bearing known as footstep bearing. If the axis of the shaft is horizontal, the thrust bearing known as coller bearing.