NBC Ball Bearings 621XXX Series to 625XXX Series

⚙️ What Are Ball Bearings?

Ball bearings are mechanical components designed to reduce friction and support rotational or linear motion between two parts — typically a shaft (rotating element) and a housing (stationary part). They achieve this by using rolling spherical balls placed between two rings (races).

Because rolling friction is much lower than sliding friction, ball bearings enable smooth, efficient, and low-friction motion even under heavy loads and high speeds.

🧩 Construction of a Ball Bearing

A typical ball bearing consists of the following components:

1. Inner Ring – Mounted on the rotating shaft and rotates with it.

2. Outer Ring – Fixed in the housing and remains stationary.

3. Balls (Rolling Elements) – Small hardened steel spheres that roll between the rings.

4. Cage (Retainer) – Holds the balls evenly spaced and guides their motion.

5. Seals/Shields (optional) – Protect the internal parts from dust, moisture, and contaminants.

🔧 Working Principle:
When the inner ring rotates, the balls roll along the grooves (raceways) of the inner and outer rings. This rolling motion drastically reduces friction compared to sliding contact, allowing smooth rotation with minimal energy loss.