The lubrication principle of the KAZ87-17.42-18.5KW gear reducer in high temperature environment is 'mainly oil film bearing, supplemented by forced circulating heat dissipation, combined with extreme pressure and antioxidant additives', the oil film bearing and thermal balance are managed simultaneously, and the operating oil temperature is controlled at 80–85 ℃, temperature rise ≤40 K, and vibration RMS ≤4.5 mm/s.
Oil film bearing and friction mechanism
Fluid dynamic lubrication (EHL): The gear moves relative to the gear and brings oil into the meshing area to form a continuous oil film, which turns metal contact into friction within the oil film, reducing friction coefficient and wear.
Elastic fluid dynamic lubrication (EHL): The heavy-load contact area produces elastic deformation and high pressure, the oil film bearing is significantly enhanced, and it is effectively resists glue and fatigue.
Boundary lubrication: When starting and stopping, low speed or high temperature peaks, the oil film becomes thinner, polar molecules adsorb into a boundary film, and a reaction film is formed on the metal surface by extreme pressure additives to inhibit wear and glue.
Heat dissipation and temperature control
Forced circulation heat dissipation: When high temperature or near/ exceeds the thermal power PG1, use an oil pump to circulate + cooling coil (air-cooled or water-cooled) to quickly bring the friction heat out of the box and uniformize the temperature field to avoid local overheating.
Heat dissipation capacity and flow rate: The circulating oil volume is recommended to be ≥0.5 L/(kW・min), or calculated according to thermal equilibrium and glue strength to ensure that the oil temperature is stable within the target range.
Additives and protection
Anti-wear/extreme pressure (EP): contains S/P/Cl, etc., and reacts with metal under high temperature and high pressure to form a protective film with low shear strength, inhibiting glue and abrasion.
Anti-oxidation/rust/anti-foaming: delays oil oxidation, isolates moisture and corrosive media, and inhibits foam to ensure smooth lubrication and heat dissipation channels.
Lubrication method and selection
Usually: low-speed heavy-load priority oil pool/splash lubrication; when the circumferential speed > 12 m/s or when the high temperature is close to PG1, use oil injection (forced circulation) lubrication instead.
Viscosity and oil type: high temperature, impact/heavy load conditions are preferred for synthetic heavy-load gear oil, such as ISO VG 220–320; VG 220 is commonly used for circulation lubrication, and VG 320 is commonly used for oil pool lubrication, so as to take into account both load bearing and heat dissipation.
