Gears

TM 750-245-4

operational check of the items in which the bearing was

10-11. Oil Seals

replaced.

In any lubricating system, it is just as important to "seal

in" the lubricant as it is to "seal out" contamination. The

inspector can insure compliance by in-process

10-9. Gears

inspection of oil seal installation and close checks for

a. The inspector must be familiar with the

leakage.

operation and purpose of gears before he can determine

when gears are defective and should be replaced.

10-12. Oil Filters

b. Inspection of gears which usually are encased

Good quality oil filters are necessary to remove

will have to be accomplished during an in-process

contamination from oil in a circulating system. It is the

inspection. The inspector should inspect, using table

inspector's responsibility to inspect to insure that proper

10-1 as a reference, for type of gear wear and possible

oil filter change has been made. As a general rule,

correction.

anytime maintenance is performed on any system which

c. Final inspection should insure that the proper

requires a lubricated part to be changed, the filter should

lubricants were used, the gears operate properly, and

also be changed. Lubrication orders should be closely

there is no leakage around seals.

followed here.

10-10. Wire Rope

10-13. Miscellaneous

Inspect wire ropes to insure proper lubrication so that it

Many other items and components such as fans,

will function dependably during service. Lubrication is

motors, pumps, shafts, flexible couplings, and chains

especially critical because of exposure to weather, water

require constant lubrication, and must be inspected to

washings, dust, and other contaminations. Although

assure that quality of lubricant, application methods,

wire rope is lubricated when manufactured, serious

seals, and lubrication practices conform to standards

damage can result through internal and external

and lubrication order requirements. A good knowledge

corrosion and friction if proper lubrication is not

of these components, attention to details of applicable

continued.

Refer to lubrication order or technical

lubrication orders, and special inspection procedures are

manual.

required for adequate inspection, and assurance that

components are kept in required condition.

Table 10-1. Types of Gear Wear Observed After Use

Condition

Type of gear

Probable cause

Possible correction

Abrasion

All types

Contaminants either metal or

Change oil and flush out case

other particles

before renewal.

Burning

All types

Lack of lubricant or overload.

Proved enough oil, decrease load if

possible.

Galling

Bevel, hypoid, spiral

High surface temperature or oil

Use means to reduce operating

film rupture.

temperature. Check type oil being

used. Change per LO.

Pitting

All types

Oil viscosity too low, rough

Increase oil viscosity and substitute

surface,

too

high

local

oil, better gear surface finish. Initial

pressure.

pitting may cease after run-in

period.

Scoring

Bevel, helical, and spur

Too low a viscosity oil; sliding

Increase oil viscosity or use oil with

types

under heavy load; rough

EP agent, preheat before starting.

surfaces;

improper

tooth

contact, perhaps due to

misalinement; temperature low

when starting.

10-2