Issue link: http://read.dmtmag.com/i/859318
Gear Lubricants Background & Properties castrol.com/GPS 800 255 4417 May 2025 GPS Important Gear Lubricant Properties Important Gear Lubricant Properties Gear lubricants perform a number of duties within a gear set including preventing metal-to-metal contact, providing good shiability in all temperatures, dissipating heat, preventing rust, removing wear debris and reducing friction. Specially formulated gear lubricants work to optimize performance and preserve the gear itself. When choosing a gear lubricant, several factors should help to determine final lubricant choice, including: Extreme Pressure Extreme pressure characteristics are especially important to gear lubricants. In some cases, EP additives account for up to 80% of a gear oil's additive package. EP additives work to protect the gear face from high temperatures and prevent metals from welding together and tearing apart. Gear Type Wear resistance is especially important with spur and bevel gear lubrication since only one tooth carries the entire load. With spiral bevel, helical and herringbone gears, the sliding action tends to wipe away the lubricant, which dictates the need for a slightly higher viscosity lubricant. e lubricant for these gears must provide good film protection but not excessive so that friction is increased. Worm gears also employ sliding motion and therefore require a higher viscosity lubricant. Lubricants that are compounded are usually specified for these gears. Hypoid gears by design require lubricants with EP additives to combat the changing boundary and film conditions. Gear Speed Low viscosity oils can be used in higher speed gear operations because speed reduces the metal-to-metal contact and actually assists in forming fluid films. High viscosity oils are typically used in low speed gear assemblies because there is ample time for fluid films to deteriorate. Reduction Ratio e reduction ratio is a vital piece of information because it usually foretells of multiple reduction gears. Each reduction set operates at a different speed; the first set being the highest speed and the last set being the lowest. e inverse relationship between gear speed and oil viscosity holds true for multiple reduction sets. Two ways to lubricate multiple gear reducers are to use a dual viscosity oil system, or to try circulating the cool oil to low speed gears and then transferring it to the higher speed gears aer its temperature is increased and viscosity decreased. Operating Temperature Ambient and operating temperatures affect an oil's viscosity and oxidation resistance and are therefore critical pieces of information in selecting a lubricant. To determine the operating temperature of a gear set, take the rise in operating temperature and add it to the ambient temperature. Choose the appropriate lubricant for the calculated temperature range. E9 ecastrof