Trouble Symptoms, Causes and Countermeasures

In the event of an abnormality in the equipment incorporating the ball bearing, or damage or breakage of the ball bearing, the cause can be investigated based on the symptoms and conditions. The following shows typical abnormalities and countermeasures.

Abnormal symptoms and conditions

Symptoms and conditions		Bearing damage, assumed cause, etc.	Damage example	Countermeasures
Abnormal sound	Continuous sound	Raceway brinelling	3	Reviewing handling of bearings, assembling and transporting equipment(whether excessive load or impact load is applied)
		Roughness and wear	1	Reviewing lubricant, bearing size, preload and seal
		Scratches due to foreign matter in the raceway (indentation)	2	Using seal for bearings and reviewing work environment
		Fretting	4	Reviewing vibration elimination, packaging and transportation
		Electrical arc pitting	6	Insulation: Make the ball ceramic
		Component resonance		Reviewing dimensions (thickness) and material of components
	Variable sound	When the ball is scratched		Reviewing work environment and work(whether foreign matter is intruding or excessive load is applied)
		Biting of foreign matter		Using seal for bearings and reviewing work environment
		Insufficient preload		Reviewing preload amount based on load, rotation conditions, etc.
Rotation failure	Does not rotate or rotation is heavy	Effect (amount, type) of lubricant (grease)		Reviewing grease Improvement of driving parts (motor parts, etc.) (increase the driving power, etc.)
		Foreign matter penetration, adhesive penetration		Reviewing usage environment and work methods
		Large interference		Reviewing fits
		Out of lubrication		Reviewing lubricants and increasing the amount of grease Reviewing the grease type and amount
		Flaking	8	Checking load and rotation conditions Selecting a larger bearing
		Component contact		Reviewing work and design
	Heat generation	Incorrect grease type and filling amount		Reviewing grease
	Heat generation	Overload		Reviewing load capacity and fits
	Short life	Unsuitable environment, usage conditions, etc.		Reviewing environment and usage conditions
Large vibration and runout		Misalignment		Reviewing component dimensional tolerance, cleanliness and process
		Deformation of track surface		Reviewing machining precision (roundness) of shaft or housing Reviewing adhesives and bonding work
		Improper preload Preload reduction		Reviewing preload amount based on load, rotation conditions, etc.
		Excessive internal clearance		Reducing bearing internal clearance
		Creep	5	Reviewing fits
Grease leakage		Incorrect grease type and filling amount		Reviewing grease
Grease leakage		Incorrect selection of shield/seal		Reviewing shield and seal
Damaged (cracked) resin material		Chemical attack	7	Reviewing lubricants, relieving stress and reselecting resin
		Excessive interference		Reviewing fits
		Weld line		Reviewing molding conditions and gate position