Bearings are "parts that assist objects' rotation". They support the shaft that rotates inside the machinery.

 Machines that use bearings include automobiles, airplanes, electric generators and so on. They are even used in household appliances that we all use every day, such as refrigerators, vacuum cleaners and air-conditioners.Bearings support the rotating shafts of the wheels, gears, turbines, rotors, etc. in those machines, allowing them to rotate more smoothly.

In this way, all sorts of machines require a great many shafts for rotation, which means bearings are almost always used, to the point where they have become known as "the bread and butter of the machine industry". At first glance, bearings may seem like simple mechanical parts, but we could not survive without bearings.