BEARING LUBRICATION TYPES CHART
Sleeve bearings may be broadly classified into two types, i.e., liquid lubricated and dry or solid lubricated.
Liquid lubricated bearings depend on separation of the bearing and journal surfaces by means of a hydrodynamic film in which pressures generated by sheer forces in the film are high enough to support the load.
We recommend relubrication of bearings at time of installation even though a full supply of oil is provided at the factory. Conditions encountered during shipping and storage may tend to cause some oil loss. Once the bearing is in use and the ball is filled with oil, trouble-free operation may be expected for an extended period under proper operating conditions. Standard oil supplied is a good grade of industrial mineral oil (non-detergent) SAE 30 viscosity. Bearing use at elevated or very low temperatures may require oil of different viscosities.
Bearings of this type which operate at high or moderate speeds under relatively clean conditions are generally oil lubricated since oil will provide the necessary lubricity and film pressures without excessive drag due to viscosity.
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(P) - Non-refillable oil
(A) - Refillable oil cup at a vertical angle
(K) - Refillable oil cup of varying angles (0-30˚)
At lower speeds, and particularly where a significant amount of load is involved, a heavier lubricant such as grease is preferred since the increased viscosity will build up film pressure.
Bearings with grease fittings are not factory lubricated. Grease should be applied with a pressure gun at installation, filling the ball unit and bearing until grease appears at the shaft service. [Please be aware that all Triangle bearings are shipped without grease so the user can have control over the lubrication selection, which will vary based on application.]
The grease also restricts entrance of contaminants from outside, so it is preferred for dusty and dirty applications.
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(G) - Refillable grease zerk/fitting at a vertical angle
(J) - Refillable grease zerk/fitting of varying angles (0-30˚)
Gulf Plastic Petroleum "E", although solid at temperatures below 160˚ F., really is classified as a liquid, since the thixotropic properties of this material cause a drop in viscosity as soon as the shaft starts to turn. It feeds slowly through the bushing by capillary action, replacing lubricant which has been dissipated.
Ball units are factory lubricated and many be closed balls or equipped with removable plugs for relubrication. In either case, in proper applications, bearings lubricated with Plastic E will give satisfactory performance for a number of years without relubrication. Recommended operating temperatures range from 30˚ F to 120˚ F. Frequency as well as length of operation are important factors in the use Plastic E in various applications.
It finds common usage in blower bearings for the heating and air conditioning industry in "sealed for Iife" type applications. Bushing materials commonly used in liquid lubricated bearings are sintered bronze and grooved and graphited cast bronze.
Dry lubricated bearings will operate satisfactorily without supplementary lubrication, but at relatively low loads and speeds. In addition, the dry bearing wear rate is relatively high, so that expected service life is less than would be obtained from a liquid lubricated bearing. They do, however, offer economy and freedom from contamination of adjacent parts or materials by oily lubricants. The N Series nylon ball is representative of this type.
[Please conduct regular periodic inspections and lubrication programs to guarantee a long bearing life.]