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Engineering Reference

Noise & Vibration Level Guide

Reference vibration acceleration levels for deep groove ball bearings by bore diameter. Compare Z1–Z4 quality grades per JB/T 7047.

All grades
Z1 — Standard
Z2 — Low noise
Z3 — Very low noise
Z4 — Ultra low noise
Z1 (quiet motor) Z2 (precision) Z3 (instrument) Z4 (ultra-precision)

Vibration Acceleration Levels — Deep Groove Ball Bearings

Values in dB (acceleration base). Per JB/T 7047 / industry reference. Select a grade above to filter.

Bore diameter (mm) Z1 (dB) Z2 (dB) Z3 (dB) Z4 (dB)

What is Z-grade?

Vibration grades classify bearing noise by acceleration level. Z1 is basic quality; Z4 is for noise-critical applications like precision motors, medical devices, and audio equipment.

How to choose

Z1/Z2: general motors, fans, pumps, household appliances.
Z3: precision motors, air conditioners, automotive.
Z4: instruments, medical, aerospace, audio.

What affects noise

Surface roughness of raceways, ball roundness, cage design, cleanliness, lubricant type, and internal clearance. Tighter clearance (C2) often reduces noise but increases heat.

Need low-noise bearings? NLHB supplies Z2–Z4 grade deep groove ball bearings with controlled raceway roughness (Ra ≤ 0.05µm) and full noise testing. Request a quote with your model and required grade — we provide actual test data with each batch.
About these values: The reference table shows typical vibration acceleration limits per JB/T 7047 for open deep groove ball bearings at standard test speed (1500 rpm for d≤60mm, 1800 rpm for larger). Shielded/sealed bearings and different lubricants will change actual values. NLHB is building a real measured-noise database — if you have specific noise requirements, please specify in your inquiry and we will match or exceed the required grade.

Testing Method (JB/T 7047)

Bearing vibration is measured using an accelerometer mounted on the outer ring while the inner ring rotates at a defined speed. Three frequency bands are evaluated:

The overall acceleration level (dB) shown in the table is a common acceptance criterion. Test scope, sampling frequency and report availability are confirmed for the specific order.