Machinery Lubrication

Machinery Lubrication July Aug 2013

Machinery Lubrication magazine published by Noria Corporation

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Gear Lubrication AS I SEE IT JIM FITCH NORIA CORPORATION ADD OIL CIRCULATION to Gear and Bearing SUMPS for GREATER Reliability The designs of many common machine mechanisms have not changed significantly in decades (centuries in some cases). This is especially true where lubrication is involved. Apparently, machine designers working for original equipment manufacturers (OEMs) are under the impression that lubrication has not been, or simply cannot be, improved. Sadly, there are new machines manufactured today based on this false premise. Conspicuous evidence of this is seen in many wet-sump oil systems found in pumps, gearing and bearings. • Splash Lubrication — Gear movement passing through an oil sump produces a splash or mist throughout the gearset to wet machine surfaces. • Climbing-Oil Lubrication — Gears rotating through a wet sump lift clinging oil into gear mesh zones. Some use paddle gears to help lift and transfer oil to loaded gears. All of these methods provide little more than basic lubricant supply. Today's reliability organizations demand more than this, especially for machines that are prone to failure and/or have high machine criticality. One easy improvement that can be installed by many users is of lubrication profesto retrofit an oil circulation unit to an sionals use sump systems that do not circulate oil, existing wet-sump system. The benebased on a recent poll at fits of circulation are not always fully understood by users and machine designers. This is one of the reasons why the added cost of oil circulation is dismissed as a necessary expense Good examples are the many noncirculating bearing and gear sumps that by both OEMs and users alike. There are four basic types of oil circulafeed oil to frictional surfaces. These are wet-sump lubrication (WSL) systems that tion systems: 1.Oil-feed Circulation — This is a wetdeliver lubricants using one of the sump system that pumps oil from the following methods: sump through lines that direct lubricant • Flood Lubrication — Frictional surfaces to lubricated surfaces (cams, bearings, are submerged in a bath of oil. cylinders, gears, etc.). For instance, • Slinger/Flinger Lubrication — Moving diesel engines use oil-feed circulation. parts cup and toss oil to troughs and 2.Constant-level Circulation — This frictional zones. system uses a small external reservoir in • Oil Ring/Collar Lubrication — Rotating addition to the machine's wet sump. rings and collars lift oil to the top of The wet sump supplies oil to the channels and grooves where oil is fed machine's frictional surfaces by one of into bearings by gravity. the WSL methods mentioned earlier. 64% 2| July - August 2013 | 3.Off-line Circulation — This is a simple kidney-loop system used to provide offline filtration and temperature control. Oil-feed Circulation Constant-level Circulation Off-line Circulation Hydraulic System Figure 1. This illustration shows the four basic types of oil circulation systems.

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