Shaft and bearing together form a unique and useful combination for machine elements. Domestic appliances like kitchen grinder, blender, refrigerator, washer, air conditioning, water booster pump, and lots of more machines are dependent on the movement of these two machine elements. All our other equipment’s from the surface to space can not move without the use of shaft and bearing combination. Shaft and bearing combination transmit the motion and power from one machine to another. Shaft and bearing are specifically designed to undertake the static as well as dynamic loads of the machines when they are in motion.
The shafts are used in all mechanical equipment. The shafts are the cylindrical long machine elements. They’re usually in circular cross-sections. In any mechanical equipment shaft is its backbone. One end of the equipment shaft is connected to the prime mover shaft with the help of coupling, which provides the rotational movement to the equipment. This way the equipment starts delivering, its intended function. The motor shaft is mounted with a pulley or gear which is connected to another machine to transmit the motion and power. Bearings provide support to the shaft for mounting in the machine.
Shafts are manufactured from forged steel bar stocks. Shafts are subjected to varied loads like radial thrust and axial thrust. These loads are absorbed by the bearings on the shaft. The shaft is subjected to torsional stress and repeated cyclic bending loads on the overhung length of the shaft while in motion. Repeated cyclic bending loads may cause deflection in the overhang length of the shaft. The shaft to be designed for higher stiffness to withstand the deflection. The stiffness of the shaft is L3/D4, Where D- is the diameter of the shaft, and L- is the overhang length of the shaft. Shafts transmit motion and power to the machine in the horizontal plane or in a vertical plane. Depending on the application the shafts are made as hollow shafts or solid or rigid shafts. The number of bearing supports is decided to support the shaft according to the long span of the shaft.
Ball-bearing is a common type of machine element. it’s fitted on a shaft. Shaft and ball bearing are housed in the machine bearing housing. Ball bearings provide proper support to the shaft. They permit the shaft to rotate freely without fiction and transmit the power to the different machines.
Ball bearings usually consist of four main parts:
(1)an inner ring,
(2)an outer ring,
(3) the ball,
(4) the cage or separator.
The rings of the bearing are given a deep groove in which the ball moves. Groove increases the surface contact area of the ball and the load-carrying capacity of the bearing.
Ball bearings are manufactured in many types. Single row radial ball bearings are manufactured in four series:
1) Extra light 100 series
2) Light 200 series
3) Medium 300 series
4) Heavy 400 series.
Other ball bearings are classified on their load-carrying capacity mentioned as follows:
(1)Axial thrust bearing:
Axial thrust bearings are used when the entire load is in the axial direction of the shaft, radial thrust bearings are used.
(2)Angular contact bearings:
Angular contact ball bearings are good for both radial and axial loads
The self-aligning ball bearings accommodate the huge amount of angular MIS alignment.
Ball bearings are made from high carbon stainless steel52100. Ball and rings are made of steel 52100l. They’re heat-treated for good strength and hardness. Self-aligned bearings components are smoothly ground and polished.
Roller bearings are used when shock and impact loads exist. They’re used where large size bearings are needed. Roller bearings are made from four main parts: inner ring, outer ring, roller, and separator. Depending on load-carrying capacities roller bearings are classified as follows
(1)Cylindrical roller bearing
(2)Flexible roller bearing
(3)Needle roller bearing
(4)Tapered roller bearing
(5)Spherical roller bearing
(6)Roller thrust bearing