High precision ball bearings - Spekuma Kullager AB

www.gmn.deBearing frequenciesServiceStructure-borne noiseGMN bearing analysisConsultationThe design and geometry of the individual components, as well asthe design of the entire bearing, determine bearing frequencies.The characteristic structure-borne noise level of a ball bearing iscomposed of the sum of all bearing frequencies.Structure-borne noise relevant factors:· Form accuracy and surface grade ofraceways and balls· Cage version· Cleanliness and type of lubricationOn the basis of structure-borne noise tests, bearing vibrations canbe determined and conclusions drawn about the surface condition(waviness) of bearing rings and balls.Low noise levels are the result of smooth running and low frictionwhich indicate high performance and long service life of the bearing.Micrometer2,01,51,00,50,0-0,5-1,0-1,5-2,051,9 52,0 52,1 52,2 52,3 52,4 52,5 52,6 52,7 52,8 52,9 53,0 53,1 53,2 53,3 53,4 53,5 53,6 53,7 53,8MillimeterCalculation of bearing-specific frequenciesBall passing frequency f AR on outer ring:( )f AR = –– Z · f i · 1 – D W––– cos α 0 [1/sec]2d mBall passing frequency f iR on inner ring:( )f IR = –– Z · f i · 1 + D W––– cos α 0 [1/sec]2d mBall circulation frequency f W :d D(m W)f W = f i–– · ––– – ––– cosD 2 α 0 [1/sec]2 W d mCage frequency f K :( )f K = f i–– · 1 –2 ––– D Wd cos α 0 [1/sec]mf i =Shaft frequency [1/s]D W =Ball diameter [mm]d m =Pitch circle diameter [mm]Z=Number of ballsα 0 =Contact angleRapid, uncomplicated calculation of bearing-specific frequencies:www.gmn.de: "GLOBUS 2005"More than 50% of all bearing damage results from inadequate lubrication,more than 40% is caused by faulty design, installationdefects and contamination.Less than 1% of all bearings fail due to material or manufacturerdefects.Bearing analyses performed by GMN permit conclusions to bedrawn about the causes of impairment and provide solutionswhich enable reliable operation of the bearing application.· Assessment of cause(s) of bearing damage orinadequate processing results· Consultation about cause elimination· Prevention of same or similar damage· Optimization of the bearing with respect to machine duty cycle,processing accuracy and performance· Use of analysis results for product improvementsGMN offers comprehensive investigative methods for bearinganalysis.· Noise test· Metrological investigation(bearing and component measurements)· Microscopic investigation (including REM)· Lubricant analysis· Calculation review (e.g. check of preload)· Weak-point analysisIn order to achieve specific and meaningful results in bearing analysis,the following approach should be pursued:· Remove the bearing immediately after the damage event oroperating abnormality· Mark the installation position(fixed/floating bearing, load direction, drawing/sketch)On the basis of long experience in the practical application ofmachine components, GMN provides comprehensive consultationand services in the field of high precision ball bearings that support 0machine systems.· Bearing selection, bearing calculation, service life calculationCharacteristic values, bearing frequencies, installation dimensions …· Tribology, lubrication, lubricant selection,grease consumption life calculation· Recoding of competitive products· Optimizations for special applications· Special solutions· Damage analysisTraining coursesGMN provides qualified training courses in theory and practice forhigh precision ball bearings and their applications, both at customerlocations and also at our premises.Subjects and contents of training courses are focused on theindividual customer requirements.· Essentials: products, designs, materials, accuraciesand tolerances· Engineering: nomenclature, bearing selection, bearingarrangements, preload, matching, lubrication, calculation· Installation: workplace layout, tools, control measurementslubrication, installation, grease distribution run· Bearing analysis: reasons for bearing investigations, methodology,investigation options at GMN· Return the bearing uncleaned with all parts· Inform us about the application, operating conditions, load,speed and time installed92 93