Question

Why are ball bearings used in machinery?

Answer 1

Hint: A ball bearing is a form of rolling-element bearing which uses balls to hold the bearing breed apart. A ball bearing is intended to reduce rotational friction and to accommodate radial and axial loads. It is done by using at least two races to hold the balls and distribute the loads through the balls. One race is stationary in most applications, and the other is attached to the rotating assembly (e.g., a hub or shaft). When one of the bearing species rotates it also causes the balls to rotate. Since the balls roll, they have a much lower friction coefficient than if two smooth surfaces rolled against each other.

Complete step-by-step solution -
Ball bearings are used in devices that have a lot of motion in their cycle of operating. Ball bearings minimize friction during travel, resulting in improved machine performance and smooth movement.

Additional information- A ball bearing has three main parts: two grooved, ring-like races, or tracks, and a number of balls of hardened steel. The races are of the same width but different diameters; the smaller one is attached to one of the machine members, fitting inside the bigger one and having a groove on its outside surface. The larger race has a groove on its interior surface and is attached to the other machine member on its external surface. The balls fill the gap between the two races and roll in the grooves with negligible friction. The balls are contained loosely and separated by means of a retainer or cage.

Note: In such questions, the concept of friction is used i.e. Sometimes friction is a must. One simple example is that it takes friction to walk. Friction occurs as we walk between our feet and the ground. Unless the ground was completely smooth, we would still be able to fall and never push forward. Similarly, a tire requires traction to travel to the ground. Without the absence of friction, cars too will never be able to stop while in motion. Friction works on the tires as brakes are applied, and forces the car to stop.