제일베어링공업(주)

Leader of the 21st Century

The growing company with constant passion

제일베어링공업(주)

HOME > Technical Know-How > Bearing Dr > Handling of bearings


	As rolling beating is the part of precision machine a cautious handling is a must. Even a highly efficient equipment it would not function properly if it not handled as instructed. The followings shall be observed in handling the bearings. (1) Bearing and the surroundings shall be maintained clean (no foreign material) (2) Bearings shall be handled cautiously (no impact) (3) Proper tools shall be used (no tools for other purpose) (4) Bearings shall be protected from corrosion (wearing gloves when handling bearing and bearing shall kept away from corrosive gas)


	A life-span and performance of beating are affected by proper installation of bearing, and thus the following standards shall be considered in assembling process. (1) Cleaning the bearing and accessories (2) Checking the dimension and finish (3) Assembly method (4) Checking after assembling (5) Lubricating Considering the axial rotation of bearings, inner side shall be tightened, while outer side loosened when assembling.

Operation test shall be conducted after assembling. Chart 2 summarizes the test process. When abnormal function is detected, the operation shall be stopped for inspection. Please refer to Chart 2 for cause and countermeasures.

Chart 1 Operation test process


Machines	Operation Method	Test Items

Small machine	Manual operation If the test is acceptable, operation starts	● Blocked (foreign material, scratch, indentation) ● Irregular torque (poor assembly) ● Excessive torque (narrow gap / assembly error)

	Power operation Machine shall start at no-load and low-speed and gradually turn into to regular operation.	abnormal sound and bearing temperature Leakage and discoloration of lubricant

Large machine	Power operation at low speed Machine shall start at no-load and turn into low speed operation without power. If no problem is detected, it shall turn into power operation	Vibration and noise

	Power operation Same as power operation of small machine	Same as the items of small machine.

Chart 2 Abnormal operation and cause & countermeasures


Operation		Cause suspected	Countermeasures

Noise	Metallic high tone	Abnormal load	Fitting adjustment, bearing clearance check, preload adjustment, housing shoulder adjustment

		Poor assembly	Axis/housing finish level, assembly improvement

		Low /inappropriate lubricant	Refueling lubricant, selection of appropriate lubricant

		Contact with rotating parts	Adjustment of contact part such as Labyrinth

	Regular sound	Rust, scratch on surface	Bearing replacement, cleaning, sealing improvement and clean lubricant

		Brinelling denting	Bearing replacement, cautious handling

		Flaking on surface	Bearing replacement

	Irregular sound	Excessive clearance	Fitting and bearing clearance check, adjustment of preload

		Foreign material	Bearing replacement, cleaning, sealing improvement and clean lubricant

		Scratch, flaking on ball	Bearing replacement

Temperature rising		Excessive lubricant	Reducing lubricant, selection of hardened grease

		Low /inappropriate lubricant	Refueling lubricant, selection of appropriate lubricant

		Abnormal load	Fitting adjustment, bearing clearance check, preload adjustment, housing shoulder adjustment

		Poor assembly	Axis/housing finish level, assembly improvement

		Excessive friction of creep sealing on fitting surface	Bearing replacement, fitting check, axis/housing adjustment, sealing improvement

Significant vibration (shaking axis)		Brinelling indentation	Bearing replacement, cautious handling

		Flaking	Bearing replacement

		Poor assembly	Adjustment of perpendicularity of axis housing and side support

		Foreign material	Bearing replacement, cleaning of parts, sealing improvement

Significant lubricant leaks & discoloration		Excessive lubricant, foreign material, friction powder	Optimization of lubricant level, bearing and lubricant replacement, housing cleaning


	(1) Refueling interval of grease Grease tends to be performing poorly due to deterioration as times go by, requiring replacing the lubricant at appropriate interval, which depends on type, dimension and rotation speed of bearing. Fig 4.2 indicates the grease refueling interval depending on operation hours. That is, when bearing temperature exceeds 70℃, the interval of refueling shall be reduced half whenever the bearing temperature rises every 15℃. (2) Replacement interval of lubricant Replacement interval of lubricant varies depending on the condition and level lubricant. It needs to be replaced once a year when the operation temperature is below 50℃ at the environment with less foreign material, and the oil temperature is around 100℃, it needs to be replaced at every 3 months or earlier.