Evolving Beyond Engine Applications: Oil Seals and Shape Design Technology

Oil seals — one of NOK's core products — vary significantly in shape, materials and structure depending on what is being sealed, the size of the shaft they are mounted on, and the type of movement involved. NOK produces around 60,000 types of oil seals, most of which are specifically designed for particular applications. While oil seals are widely used in automobiles, those used for engines and those installed in drivetrain components require entirely different properties. Despite all being referred to as "oil seals," they are fundamentally distinct products. For example, oil seals used in hub bearings near the wheels have undergone their own unique evolution.

Using Trial and Error to Find the Perfect Blend: Oil Seals and Material Design Technology

Oil seals are one of NOK's core products. Of NOK's consolidated sales of 682.5 billion yen for the fiscal year ending March 2022, the sealing business — including oil seals — accounted for approximately 336.2 billion yen, or nearly 50%. NOK produces 60,000 types of oil seals globally, manufacturing 1.83 billion units annually. Despite their seemingly simple ring-like design, oil seals combine rubber material, metal rings, and springs to prevent oil and water leakage, achieve low friction, and ensure durability. They are essential mechanical products for all types of machinery, and one of the supporting technologies is material design.

Handling Opposing Functions: Oil Seals and Surface Design

A major independent automotive parts manufacturer highly regarded for its technical capabilities. NOK is a key supplier to all Japanese automakers. Its particular strength lies in oil seals, the product the company was founded to manufacture. Used in engines, gearboxes and hydraulic equipment, oil seals must prevent the leakage of oil, water and gases while simultaneously circulating fluids on the sealing surface to enable lubrication. This low level of friction saves energy. Although they may appear to be simple rubber rings, NOK is constantly upgrading these oil seals through improvements in surface functionality, material selection and structural enhancement when in contact with rotating shafts.