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Automotive Gear Lubricants
Published in Leslie R. Rudnick, Synthetics, Mineral Oils, and Bio-Based Lubricants, 2020
The main types of synthetic gear oils are PAO, PAO/ester, or PAO/AN based. A properly formulated all PAO gear oil will show improved properties over a comparable mineral oil–based lubricant. These include better low-temperature performance (pour point, viscosity, and channel point), increased high temperature bulk viscosity (higher VI), and improved thermal and oxidative stability. The polarity of PAO is very similar to petroleum oil with PAO-based gear oils requiring the addition of a seal swell agent for elastomer compatibility. Petroleum and PAO basestocks have a tendency to shrink and harden most automotive elastomers. Additive solubility is usually lower with PAO compared to petroleum. Petroleum oils are a complex mixture and contain low levels of polar functional groups (oxygenates, sulfur, nitrogen compounds) to assist in solubilizing polar additives. Most additive packages are very polar systems which are limited in solubility in the nonpolar PAOs. Most additive systems for gear oils (automotive and industrial) were developed for a petroleum-based system and may not be suitable for all synthetic formulations. Additive selection for synthetics and partial synthetics are affected by the type and quantity of the basestock present. The screening for acceptable additives or the incorporation of longer alkyl chains on the additive molecules may have to be considered when formulating synthetic-based lubricants.
Lubrication of Mechanical Components in Wind Turbines
Published in Bella H. Chudnovsky, Lubrication of Electrical and Mechanical Components in Electric Power Equipment, 2019
The correctly selected oil can potentially extend the life of the wind turbine gearbox, reduce downtime, and lower maintenance costs. To maximize life of the gearbox, one of the most important components of a wind turbine, the gear oil should provide long-term gear and bearing wear protection. One of the most important gearbox oil qualities is oxidation stability to extend service life; it should provide rust and corrosion protection.
Layshaft gearboxes
Published in M.J. Nunney, Light and Heavy Vehicle Technology, 2007
When a manufacturer decides upon the most suitable oil to be used in a gearbox, which may now be filled-for-life at the factory, the lubrication of the gears themselves necessarily places an emphasis on friction reduction and heat removal but, as already mentioned, the performance of the synchronizers must also be taken into account. In fact the requirements for lubricating the gears, selector forks and synchronizers may to some extent be conflicting ones. For double-stage gearboxes used in front engine, rear-wheel drive cars, an engine oil is often specified with a viscosity grade of SAE 5W-30 or 10W-30 (Section 4.3), although an automatic transmission fluid (Section 17.6) may instead be preferred in a modern five-speed transmission, to reduce gear change effort at low temperatures. With front engine, front-wheel drive cars, where a single-stage gearbox is combined with the final drive to form a transaxle, the choice of oil is determined by the lubrication requirements of the final drive gears, which in transverse engine installations are of the helical type as in the gearbox itself. For these applications a gear oil product is typically specified, which may be a synthetic oil conforming to an SAE 75W-80 or 80W-90 viscosity grade and an API GL-5 service category (Section 20.5). Some manufacturers may specify their own Gear Lubricant Special (GLS) oil for single- and double-stage gearboxes, such as the ‘Synchromesh fluids’ of General Motors and Chrysler. It is therefore most important to observe the manufacturers’ transmission oil recommendations. In the unlikely event of a modern filled-for-life transaxle requiring significant topping up, it should be carefully checked for leakage. Oil specifications for the gearboxes of heavy vehicles vary according to whether their gears are synchronized or not, and also recognize the severity of duty for which the vehicle is designed, especially in terms of gearbox operating temperatures and their effect on oil degradation.
Assessing the Influence of Micro Lubricant Additives on Worm Gearbox Power Consumption: A Tribological Investigation Utilizing Hazelnut Oil-Based Lubricants
Published in Tribology Transactions, 2023
Yunus Emre Karabacak, Hasan Baş
Worm gearboxes play a crucial role in industrial machinery, and they require specialized oils for proper lubrication. These gear oils are designed to reduce friction, create a stable tribofilm, prevent mechanical wear and corrosion, and withstand tough operating conditions. They must be able to function effectively in various situations where the speed, load, and temperature may vary, without sacrificing the oil film's load-carrying capacity. Additionally, they should not harm any mechanical parts in the system and should be environmentally friendly. To achieve all of these features, different additives are mixtured in the gear oils to improve their properties (37, 38).