What Is a Small Ball Bearing?
Small ball bearings, also known as miniature bearings, are compact bearings with an outer diameter of less than 9 mm or an outer diameter of 9 mm or more, and an inner diameter of less than 10 mm. They play a crucial role in reducing friction and maintaining the position of rotating shafts, thereby protecting the components that support rotation. Due to their critical function in many machines with rotating shafts, they are sometimes referred to as the “rice of industry”.
Applications of Small Ball Bearings
Small ball bearings are utilized in a wide range of products, including home appliances, office automation equipment, and hobby equipment. The demand for these bearings is growing rapidly in all industrial fields, driven by the trend towards smaller, lighter, and thinner products. They are found in everyday items such as fishing reels, mini 4WDs, computer hard disk spindle motors, and copier paper feed rollers. Additionally, they are instrumental in downsizing medical equipment and various measuring devices, with applications extending to potential meters, gyro gimbals and rotors, polygon scanner motors, encoders, high-frequency spindles, VTR cylinders, and capstans.
Principle of Small Ball Bearings
The operational principle of miniature bearings is the same as that of standard bearings. They are typically rolling bearings, which include rolling elements like small balls or cylindrical rollers. These elements roll within the bearing, reducing friction and facilitating smooth rotation.
1. Rolling Bearings
Rolling bearings reduce friction by allowing rolling elements to move within the bearing as the shaft rotates. This action helps in supporting the shaft and minimizing friction during operation.
2. Plain Bearings
Unlike rolling bearings, plain bearings (such as bushes) do not contain rolling elements. They rely on materials and lubricants resistant to wear and seizure to support rotational movements. Plain bearings can support larger loads due to their line contact support mechanism, compared to the point contact in ball bearings.
Other Information about Small Ball Bearings
Material of Small Ball Bearings
Small bearings are typically made from heat-treated alloy steel, with high carbon chrome steel used for the inner and outer rings and the balls, and various materials like steel plates, stainless steel, or resin for the cage. Plastic bearings, which can operate without lubrication and are resistant to rust and chemical corrosion, offer an alternative, though they generally have a lower load capacity. Plastics used in these bearings include phenolic resin, PTFE (Teflon), PEEK, PPS, PCTFE (Daiflon), and PP. However, bearings with carbon have high environmental resistance but are not suitable for applications involving high impact, vibration, or insulation requirements due to their conductivity.