TS ISO 4378-3

TS ISO 4378-3 is a terminology standard for the lubrication of plain bearings, setting out the most commonly used terms together with their definitions and a classification. Plain bearings are machine elements that support rotary or oscillating motion through sliding contact, so lubrication is central to controlling friction, wear, heat generation and running behavior. This part focuses on the language used to describe that subject, not on designing a lubrication system.

Why lubrication terms are treated separately

In plain bearings, lubrication may serve to separate surfaces, reduce friction, limit wear and help carry away heat. The value of a terminology standard in this area is consistency: terms such as lubricant film, boundary lubrication, hydrodynamic lubrication or lubricant supply can be understood in the same technical sense across design, maintenance and documentation contexts. The standard’s role is to organise the vocabulary, not to prescribe a particular bearing design practice.

What this vocabulary support is used for

• Helps technical documents, catalogs and engineering communication use the same terms consistently.
• Provides short forms for some terms and word combinations where the meaning is unambiguous.
• Supports a common classification framework for lubrication-related concepts in plain bearings.
• Reduces ambiguity between design, maintenance and specification work.