I. Core Performance Requirements
1. Superior Lubricating Performance
As a fundamental property, gear oil must form a continuous and robust oil film between gear tooth surfaces. This film effectively isolates metal contact points, reducing sliding friction and wear during gear meshing. It lowers operational energy consumption, prevents dry friction caused by oil film breakdown, and avoids issues like tooth surface seizure damage and excessive heat generation, ensuring smooth gear transmission.
2. Superior Extreme Pressure and Anti-Wear Properties
Gear transmissions frequently endure high loads and impact stresses, particularly in heavy-duty equipment where tooth surface pressures are extreme. Gear oil must possess outstanding extreme pressure and anti-wear characteristics. Its extreme pressure additives react chemically with the metal surfaces under high pressure and temperature, forming a tough protective film. This film resists heavy-load stresses, preventing severe failures like gear adhesion, pitting, and scoring, thereby ensuring stable gear transmission under demanding conditions.
3. Excellent Wide Temperature Adaptability
Gear oil must accommodate temperature fluctuations across diverse environments and operating states. In low-temperature environments, the oil must not solidify or become excessively viscous, maintaining good fluidity to ensure rapid lubrication delivery to critical areas during equipment startup, thereby preventing startup difficulties or insufficient lubrication. Under high-temperature conditions, the oil requires strong thermal stability to resist oxidation, degradation, and evaporation loss. It must also prevent a drastic viscosity drop that could compromise oil film strength, maintaining stable lubrication performance under sustained high temperatures to suit complex temperature scenarios like outdoor or high-temperature equipment.
4. Reliable Corrosion and Rust Protection
Gears, predominantly made of metal, are susceptible to rust and corrosion from moisture, atmospheric oxygen, and contaminants introduced during transmission. Gear oil must form a protective film on gear surfaces to block moisture, oxygen, and impurities, effectively preventing rust, pitting, and other issues on gear teeth and components. This is particularly crucial for equipment in humid environments or exposed to moisture (e.g., marine gear systems), significantly extending gear and equipment lifespan.
5. Superior Anti-Foaming and Water Separation Properties
During high-speed gear operation, oil readily mixes with air to form foam. Bubbles disrupt the continuity of the oil film, leading to lubrication failure. Therefore, gear oil must possess excellent anti-foaming properties to minimize foam generation and ensure rapid foam collapse. Additionally, moisture like cooling water may contaminate transmission systems. Gear oil must rapidly separate water from the oil to prevent emulsification. This avoids lubrication degradation and component corrosion caused by emulsification, ensuring stable lubrication system performance.
II. Additional Performance Requirements
1. Appropriate Viscosity Characteristics
Gear oil viscosity must precisely match gear rotational speed and load. For high-speed gears, excessive viscosity increases operational resistance and energy consumption. Conversely, for low-speed, high-load gears, insufficient viscosity fails to form an adequate oil film, leading to wear. Additionally, oil viscosity must remain relatively stable across temperature variations to ensure consistent lubrication performance under diverse operating conditions.
2. Extended Service Life and Cleanliness
Gear oil must possess strong oxidation resistance and aging resistance to prevent degradation during prolonged use. This minimizes the formation of sludge, carbon deposits, and other contaminants that could clog oil passages or cause gear surface wear. Additionally, the oil should exhibit adequate detergency and dispersancy to carry minute impurities and metal particles generated during transmission to the filter for removal. This maintains system cleanliness, reduces oil change frequency, and lowers equipment maintenance costs.