Issue link: http://read.dmtmag.com/i/859318
Gear Lubricants Background & Properties castrol.com/GPS 800 255 4417 May 2025 GPS Types of Gears Hypoid Gears A modification of the spiral bevel gear, hypoid gears transmit motion between non-intersecting shas that cross at right angles. Hypoid gears have inherently strong teeth, excellent load-carrying ability and offer noiseless operation. e sliding motion of the hypoid gear requires lubricants with EP additives to maintain film strength. Hypoid gears can be used for the most severe applications. Worm Gears When shas are intersecting at right angles and the driving gear is much smaller in diameter than the driven gear, this is called a worm gear. e two most common types of worm gears are throated and non-throated. e throated worm gear has angled teeth that increase the number of teeth in mesh at any given time. As with spiral bevel gears and helical gears, this feature increases load-carrying ability and quiets operation. On the contrary, the non-throated worm gear has only one tooth at a time in mesh, thus decreasing the gear's ability to carry loads. Due to the sliding nature of the worm gear, lubricants employing special additives are necessary. Worm gears are typically found where great velocity reductions are required. Rack and Pinion Gears A rack and pinion gear set is commonly found in automotive steering applications. Motion is transferred from the circular motion of the pinion gear to a linear gear alignment called the rack, or bar. Gear teeth are more tolerable, giving drivers a better feel while steering. Gear System Lubrication Problems e sensitive gears described above can experience problems for a number of reasons. Below are some of the more common ones: • Inadequate lubrication or low gear oil level; • Incorrect type of gear lubricant; • Wrong lubricant viscosity; • Poor-performing lubricant; • Dirty/contaminated gear lubricant; and • Misalignment of gear sets. Any or several of the above factors can contribute to gear wear. e most common types of gear wear are micro-pitting, spalling, scoring and ridging. Basically, these different types of wear cause small pieces of metal to be removed from the system, which eventually causes tooth failure and severe system contamination. E3 ecastrof