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7.4 Enclosed Gears
Gearbox Systems & Lubricants
Gearbox systems generally consist of white metal or rolling element bearings, steel on steel gears or steel on bronze gears of various configurations. The assembly is invariably fitted within an enclosure that provides both protection from external contamination and geometric alignment for the gear mesh.
Speeds and loads vary considerably depending upon the application and position of the gear within the drive train.
Simple, usually smaller, gear train systems rely on oil bath and splash lubrication. Larger, more sophisticated systems may have pumped oil supply with coolers as well as associated oil cleaning equipment such as filters and coalescers. Dedicated centrifugal oil treatment systems are desirable but rarely applied because of the high cost.
The type of oil management and oil analysis that will be appropriate to gear box oil systems can generally be categorised as: Those small capacity non-critical systems where there is no need (technical or economic) to carry out testing and where normal oil management will be by periodic change, or oil change corresponding with other maintenance on the equipment.
The more critical, usually larger, gear boxes systems where there is a risk of contamination from external sources (particularly water from coolers) and oil deterioration. Such systems tend to have relatively large oil capacities. Oil management will usually be by periodic oil sampling and monitoring of oil conditions. Oil changes may not routinely take place - oil will only be changed when necessary to rectify problems.
For those systems where it is appropriate to manage the oil by periodic oil sampling, testing should aim to assess the extent of any oil contamination and also the degree of oil degradation that has occurred. Oils within the gearbox systems require to be regarded as a ‘wearing component’. Monitoring and periodic maintenance is required to provide assurance that the machinery will continue to operate predictably with the least risk of problems occurring.
Gearbox systems generally consist of white metal or rolling element bearings, steel on steel gears or steel on bronze gears of various configurations. The assembly is invariably fitted within an enclosure that provides both protection from external contamination and geometric alignment for the gear mesh.
Speeds and loads vary considerably depending upon the application and position of the gear within the drive train.
Simple, usually smaller, gear train systems rely on oil bath and splash lubrication. Larger, more sophisticated systems may have pumped oil supply with coolers as well as associated oil cleaning equipment such as filters and coalescers. Dedicated centrifugal oil treatment systems are desirable but rarely applied because of the high cost.
The type of oil management and oil analysis that will be appropriate to gear box oil systems can generally be categorised as: Those small capacity non-critical systems where there is no need (technical or economic) to carry out testing and where normal oil management will be by periodic change, or oil change corresponding with other maintenance on the equipment.
The more critical, usually larger, gear boxes systems where there is a risk of contamination from external sources (particularly water from coolers) and oil deterioration. Such systems tend to have relatively large oil capacities. Oil management will usually be by periodic oil sampling and monitoring of oil conditions. Oil changes may not routinely take place - oil will only be changed when necessary to rectify problems.
For those systems where it is appropriate to manage the oil by periodic oil sampling, testing should aim to assess the extent of any oil contamination and also the degree of oil degradation that has occurred. Oils within the gearbox systems require to be regarded as a ‘wearing component’. Monitoring and periodic maintenance is required to provide assurance that the machinery will continue to operate predictably with the least risk of problems occurring.
