Technology

VIBRATION AND NOISE

Bearing acoustical noise is a function of both the bearing itself and the way in which it is used. Bearings can be specified as 100% noise-tested during manufacture. Bearing noise is not generally influenced by ABEC precision, but rather by manufacturers’ internal quality standards, particularly raceway finish. There are no fixed reference standards among manufacturers for noise testing


External factors affecting bearing noise include lubricant type, excessive load, improper fitting, preload method, and other factors. In particular, it is recommended that the stationary ring always be securely immobilized during high speed rotation

Vibration acceleration is an indication of vibratory force (force = mass x acceleration) and since force is damaging at higher frequencies, vibration acceleration is a useful measurement where a bearing will experience vibration frequencies above 2000 Hz. Vibration acceleration is measured in G (1G being the acceleration produced by the Earth's gravity or 9.81 m/s2) but you will often see these measurements converted to decibels (dB). These decibel measurements are usually classified into Z grades (Z1, Z2, Z3 or Z4). Bearings can be classified according to both vibration velocity AND vibration acceleration levels (ZV1, ZV2, ZV3 or ZV4).


A low noise/vibration rating is achieved by paying particular attention to the surface finish of the raceways and balls, the roundness of the rings and balls and correct cage design. We have three ratings for EMQ low noise bearings: EMQ (ZV2), EMQ2 (ZV3) and the quietest, EMQ3 (ZV4). These ratings are independent of precision grade, for example, a P6 bearing may be offered with any of the three noise ratings. To help reduce noise levels even further, low noise greases are available and the choice is now greater due to improved lubricant manufacturing techniques. These greases are more finely filtered and contain fewer, smaller solid particles.


The vibration and noise of bearings are classified as four classed as Z1,Z2,Z3 and Z4.It is measured by the instrument of S0910-1,For special requirement,it is measured by BVT-1 and classified as V1, V2, V3 and V4.The data are shown as below. Customer need mark their requirement of vibration and noise class on the order.


Tolerance data for vibration of single bearing                                       Tolerance in um/s 

dVV1V2V3V4

mmLowMediumHighLowMediumHighLowMediumHighLowMediumHighLowMediumHigh

BrandBrandBrandBrandBrandBrandBrandBrandBrandBrandBrandBrandBrandBrandBrand
3,4804444603532482622311615281010
5,61107260744840583630352118321111
7,8,91309680926654724840442824381212
10,121601201001208070906050553530451415
15210150120150100851107860654635521818
17210150120150100851107860654635522525
2026019015018012510013010075806045602525
22,2526019015018012510013010075806045603032
2826019015018012510013010075806045603540
30,32300240190200150130150120100907560703540
35300240190200150130150120100907560704245
403603002602401801601801501301109080825050
453603002602401801601801501301109080826060
50420320320280200200210160160125100100957070


Maximum vibration acceleration of single bearing                                        Tolerance in dB 

dDiameter Series(0)Diameter Series(2)Diameter Series(3)
mmZZ1Z2Z3ZZ1Z2Z3Z4ZZ1Z2Z3Z4
33534322836353230_37363331_
43534322836353230_37363331_
53736343038373432_39373533_
63736343038373432_39373533_
73938353140383634______
83938353140383634______
94140363242403735______
104342383344423935303744403732
124443393445433935304745403732
154544403546444136314846423833
174644403547454136314947423833
204745413648464238335048433934
224745413648464238335048433934
254846423849474340365149444137
284947433950484441375250454238
304947433950484441375250454238
325048444051494542385351464339
355149454152504643395452474440
405351464254524744405654494541
455553484556544946435856514744
505754504758555148456057534946
555956524960575350476259545148
606158545162595451486461565350


Particles generate noise when they pass between the balls and raceway.