What is the relationship between lubricating oil and hydraulic oil?

1. Hierarchical Relationship

• Lubricating oil

  A general category: all oils used to reduce friction, cool, seal, prevent rust, and clean are called lubricating oils.

  Includes: hydraulic oil, engine oil, gear oil, way oil, heat transfer oil, grease, etc.
• Hydraulic oil

  A type of lubricating oil specifically designed to transmit power and pressure.

2. Core Differences

• Hydraulic oil

• Main function: transmit pressure and power (like "liquid force")

• Key requirements: anti-foam, anti-emulsification, stable viscosity, rust resistance

• Used in: hydraulic systems (excavators, forklifts, injection molding machines, hydraulic presses, etc.)

• General lubricating oils (engine oil, gear oil, etc.)

• Main function: lubricate, reduce wear, dissipate heat

• Key requirements: extreme pressure & anti-wear, detergency & dispersion, high temperature resistance

• Used in: engines, gearboxes, bearings, etc.

3. Can they be mixed or interchanged?

• Using hydraulic oil as engine oil: insufficient lubrication, anti-wear and cleaning performance → may damage the engine.

• Using engine oil / gear oil as hydraulic oil: causes foaming, valve clogging, and damage to the hydraulic system.