Conventional Steel Ball Bearing Research Articles

An Adaptive Remaining Useful Life Prediction Method for Hybrid Ceramic Bearing

Ceramic bearings are quickly replacing conventional steel ball bearings in various fields and applications because they exhibit a service life three times longer than that of steel bearings. However, few studies have been reported on prognostics of ceramic bearings. Compared with the degradation process of steel bearing, the deterioration of ceramic bear contains more nonlinearity and uncertainty. The prediction of Remaining Useful Life (RUL) of ceramic bearings remains a new topic. One of the most challenging problems in the prognostic task is the lack of accurate prediction model. Particularly, when the prognostic model is trained from a data set that undergoes different degradation rate compared with the testing data set due to different load condition and service life for each individual component, the prediction often display large discrepancy. In this paper, a particle filtering based method for hybrid ceramic bearing RUL prediction is presented. An integrated adaptive model based on Recursive Least Square (RLS) is proposed to account the parameter variation of the prognostic model. The method is validated using real hybrid ceramic bearing run to failure test data. The validation results prove the effectiveness and high accuracy of the presented methodology.

Ceramic ball bearing acoustic test method

An acoustical mechanical test method prescribes compressing brittle balls in spherical conforming opposing platens producing equatorial bulging, tensile stresses, and resulting in crack or flaw growth with emissions of acoustical sounds for direct identification of brittle balls having a flaw exceeding a maximum allowable size, such as flaws in silicon-nitride balls used in hybrid bearings as well as conventional steel ball bearings.

Vibrations of the All-Ceramic Ball Bearing

All-ceramic ball bearings with silicone nitride balls and silicone nitride rings were tested and the vibration characteristics were compared with those of hybrid ceramic ball bearings and conventional steel ball bearings. The vibration measurement results showed that the overall vibratory velocity levels of the all-ceramic ball bearings are influenced by rotational velocities, and do not change with axial loads. Under a given axial load and rotational velocity, the overall vibratory velocity level of the all-ceramic ball bearing is the lowest, and the hybrid ball bearing the highest. The frequencies of main peaks in the measured vibration spectra of the all-ceramic ball bearing are higher than the frequencies of the corresponding main peaks for the hybrid ceramic ball bearing and the steel ball bearing. To explain the main peaks, modal analysis was done and the relationship between peak and natural vibration was analyzed. The results of the analyses showed that the main peaks are caused by: (1) the mass-type natural vibration of the outer ring in the vertical direction, (2) the bending natural vibration of the outer ring in the radial direction, (3) the moment of inertia-type natural vibration of the outer ring in the angular direction, (4) the mass-type natural vibration of the outer ring in the axial direction, and (5) the bending natural vibration of the outer ring in the axial direction. We also discuss the generating mechanism of the vibration and present the calculation method of the vibration spectra. As a result, it is clear that the vibration spectra of the all-ceramic ball bearing are determined by the amplitude of the waviness of the raceways and ball surface, the mobility, and the non-linear spring constant associated with the contact between the raceways and balls.

Vibration and Sound of All-Ceramic Ball Bearings. 2nd Report. Sound Characteristics of All-Ceramic Ball Bearing, and Relationship between Sound and Vibration.

The sound of all-ceramic ball bearing having silicon nitride rings and balls was investigated and compared with those of hybrid ceramic ball bearings and conventional steel ball bearings. From the experimental results and discussion, the following results were obtained. (1) The overall sound pressure level of the all-ceramic ball bearing is influenced by the rotational velocities, and does not change with axial load. (2) In the radial direction, the overall sound pressure level of the all-ceramic ball bearing is lower than that of the hybrid ceramic ball bearing and the conventional steel ball bearing. On the other hand, in the axial direction, the overall sound pressure level is about the same with the all-ceramic ball bearing, the hybrid ceramic ball bearing and the steel ball bearing. (3) The peaks of radial and axial sound of the all-ceramic ball bearing appear in higher frequencies compared with the corresponding peaks of the hybrid ceramic ball bearing and the conventional steel ball bearing. The peaks are caused by the natural vibrations of the outer ring. (4) The sound pressure of the all-ceramic ball bearing is almost in proportion to the acceleration of the vibration.

510 総セラミック玉軸受の振動と音 : 第2報,総セラミック玉軸受の音の特性,および音と振動の関係(O.S.5-2 衝突・接触問題)(オーガナイズドセッション5 : 機械の動的問題)

The sound of all-ceramic ball bearing having silicon nitride rings and balls was investigated and compared with those of hybrid ceramic ball bearings and conventional steel ball bearings. From the experimental results and discussion, the following results were obtained. (1) The overall sound pressure level of the all-ceramic ball bearing is influenced by the rotational velocities, and does not change with axial load. (2) In the radial direction, the overall sound pressure level of the all-ceramic ball bearing is lower than that of the hybrid ceramic ball bearing and the conventional steel ball bearing. On the other hand, in the axial direction, the overall sound pressure level is about the same with the all-ceramic ball bearing, the hybrid ceramic ball bearing and the steel ball bearing. (3) The peaks of radial and axial sound of the all-ceramic ball bearing appear in higher frequencies compared with the corresponding peaks of the hybrid ceramic ball bearing and the conventional steel ball bearing. The peaks are caused by the natural vibrations of the outer ring. (4) The sound pressure of the all-ceramic ball bearing is almost in proportion to the acceleration of the vibration.

Vibration and Sound of All-Ceramic Ball Bearings. 1st Report, Vibration Charecteristics of All-Ceramic Ball Baring.

The vibrations of all-ceramic ball bearings having silicon nitride rings and balls were investigated and compared with those of hybrid ceramic ball bearings and conventional steel ball bearings. From the experimental results and discussion, the following results were obtained. (1)The overall vibratory velocity level of the all-ceramic ball bearing is influenced by the rotational velocities, and do not change with axial load. (2)The overall vibratory velocity level of the all-ceramic ball bearing is lower than that of the hybrid ceramic ball bearing and the conventional steel ball bearing. (3)The peaks of radial and axial vibration of the all-ceramic ball bearing appear in higher frequencies compared with the corresponding peaks of the hybrid ceramic ball bearing and the conventional steel ball bearing. The peaks are caused by the natural vibrations of the outer ring. (4)The vibration spectra of the all-ceramic ball bearing are mainly determined by the amplitude of the waviness of the raceways and ball suface, the Hertzian spring constant associated with the elastic contact between the raceways and balls, the normal elastic contact deflection between the raceway and ball, the number of balls, the contact angle, and the mobility.

Failure modes of plasma sprayed WC–15%Co coated rolling elements

This experimental study addresses the failure modes of plasma sprayed coatings in rolling contact. A high velocity plasma spraying system was used to deposit WC–15%Co coatings on the surface of 15 mm diameter 440-C bearing steel cones. These coatings were deposited in two different thickness. Rolling contact fatigue (RCF) tests were conducted using a modified four ball machine in conventional steel ball bearing and hybrid ceramic bearing configurations. These tests were conducted under various tribological conditions of contact stress and lubrication regimes at room temperature. Failure modes were investigated on the basis of surface and subsurface observations of failed coated rolling elements. Surface observations were made using conventional scanning electron microscopy (SEM) and light microscopy. Subsurface observations were made using fluorescent dye penetrant technique. Observations of debris generated during the RCF tests, changes in topography of lower planetary balls, electron probe microscope analysis (EPMA), microhardness/fracture toughness investigations and, coating microstructural studies are also included to aid the discussion. Two modes of failures, i.e., surface wear and coating delamination, were observed during this investigation. Coated rolling elements failed in either one or a combination of these two modes depending upon the tribological conditions during the RCF test. Surface wear was associated with asperity contact in the presence of microslip/sliding within the contact region. The process was accelerated in the later stages of RCF tests in the presence of wear debris due to additional mechanism of three body abrasion. Coating delamination was associated with the initiation/propagation of subsurface cracks, which resulted due to defects in the coating microstructure. These cracks propagated at the depths of orthogonal shear stress and maximum shear stress under the surface of wear track.

Rolling contact fatigue performance of plasma sprayed coatings

This experimental study describes the Rolling Contact Fatigue (RCF) performance and the failure mechanisms of plasma sprayed tungsten carbide cobalt (WC-15%Co) coatings. The advancements of plasma spray coatings due to higher velocity and temperature of the impacting lamella call for investigations into new applications. One possible application is the rolling element bearing. A modified four ball machine which models the configuration of a deep groove rolling element ball bearing was used as an accelerated method to compare the rolling contact fatigue resistance of the test materials. RCF tests were conducted in conventional rolling element steel ball bearing (steel lower balls) and hybrid ceramic bearing (ceramic lower balls) contact configurations. Plasma sprayed coatings were deposited on a bearing steel (440-C) substrate at different thicknesses. The coated rolling element cones were ground and polished to achieve a good surface finish on the rolling elements. RCF tests were conducted under the various tribological conditions of contact stress, lubricant and test configurations. The frictional torque in the cup assembly was measured during the RCF tests with the aid of a force transducer. The speed of the planetary balls was monitored using an accelerometer and fast fourier transformation of the vibration signal. This enabled the experimental measurement of sliding between the coated cone and the driven balls. The failed rolling elements, coating debris and the lower planetary balls were analyzed for surface observations under the Scanning Electron Microscope (SEM), and Electro Probe Microscope Analysis (EPMA). The test results indicate that the coating performance was dependent upon the tribological conditions during the test. The failure modes were observed to be surface wear and the coating delamination.

Fatigue behaviour of HVOF coated M50 steel rolling elements

An experimental approach using a modified four ball machine has been used to investigate the rolling contact fatigue (RCF) performance and failure modes of WC-12Co coated rolling elements deposited by the high velocity oxyfuel (HVOF) process. The rolling elements were in the form of12·7 mm diameter M50 bearing steel rolling element balls. The RCF tests were conducted under various tribological conditions of contact loading in conventional steel ball bearing and hybrid ceramic bearing configurations. Results indicate that the rolling elements failed at contactloads above 2·4 GPa and that the failure mode was coated delamination at the coating/substrate interface. Moreover, an appreciable amount of surface wear was observed on the surface of the rolling elements after the RCF tests. The test results and failure modes are discussed in thecontext of the coating/substrate microhardness results, elastohydrodynamic lubrication (EHL) regimes, surface observation of the failed areas using scanning electron microscopy (SEM), slip analysis, frictional torque measurements, and stress contours developed by finite element modelling ofthe coated rolling element ball. Solutions to resist interfacial delamination are also discussed

Experimental measurement of the residual stress field within thermally sprayed rolling elements

A non-destructive experimental approach using an X-ray diffraction technique was used to investigate the generation of residual stresses in thermally sprayed rolling elements. The rolling elements were detonation gun coated balls and high velocity oxy-fuel coated cones. A modified four ball machine was used to perform rolling contact fatigue (RCF) tests on tungsten carbide cobalt (WC-Co) coated samples on steel substrate. RCF tests were conducted in conventional steel ball bearing and hybrid ceramic configurations. Residual stress measurements were performed at different sample orientations on different coating thicknesses and various substrate geometries. Residual stress measurements on as-sprayed samples, pre-tested samples, and after the RCF tests were performed during this study. This enabled the measurement of residual stresses generated during the thermal spraying process and due to the RCF tests. Residual stress measurements are also made on the failed areas of the coatings. Residual stress measurement results are presented in the form of principal stress values, using complex stress/strain relationships. These results indicate that residual stresses are critical to the performance of coatings. The generation of residual stresses is not only dependent upon the coating process but also on the coatings thickness and substrate geometry. RCF tests induce tensile residual stresses within the contact area and coating microstructure. Residual stress magnitude depends upon the test configuration and time of failure. Compressive residual stresses caused by the coating process are helpful as they improve the RCF life of the coatings. A multiple-cause diagram relating to the generation of residual stresses within the coatings has been presented and stress measurements have been explained with the aid of figures and scanning electron microscopy observations.

Wear of high-velocity oxy-fuel (HVOF)-coated cones in rolling contact

An experimental approach using a modified four-ball machine was used to investigate the rolling-contact fatigue (RCF) performance of tungsten carbide cobalt (WC-12%Co) coatings deposited by the high-velocity oxy-fuel (HVOF) process. The coated rolling-elements were in the geometrical shape of a cone which replaced the upper ball of the modified four-ball machine. The RCF tests simulate the configuration of a deep groove rolling-element ball bearing, and the tests were conducted in a conventional steel ball bearing and hybrid ceramic bearing configurations. The coating thickness, Hertz contact stress and the test lubricants were varied to provide various tribological conditions during the tests. Three different coating thicknesses were investigated and the coatings were ground and polished to attain a good surface finish on the rolling elements. The effect of substrate hardness, coating thickness and fluid film thickness on the RCF performance have been investigated along with the coating failure modes. Coating wear has been analysed using a scanning electron microscope (SEM) and the results discussed with the aid of the coating microstructure, microhardness and talysurf analysis of the wear track. Test results reveal that the performance of the coating is dependent upon the combination of the substrate and the coating properties. Moreover, the coating failure is a function of surface and subsurface mechanisms depending upon the tribological conditions during the test. Thinner coatings did not fail at the interface, indicating a good adhesive strength between the coating and the substrate. The depth of the failure and its comparison with the orthogonal shear-stress depth has been discussed. The coating failure was observed to be a combination of surface wear and subsurface delamination.

Rolling contact fatigue performance of detonation gun coated elements

Rolling contact fatigue performance of thermal spray coatings has been investigated using an experimental approach. A modified four ball machine which simulates a rolling element bearing was used to examine the coating performance and failure modes in a conventional steel ball bearing and hybrid ceramic bearing configurations. Tungsten carbide (WC-15% Co) and aluminium oxide (Al 2O 3) were thermally sprayed using a super D-Gun (SDG2040) on M-50 bearing steel substrate in the geometrical shape of a cone. A coated cone replaced the upper ball that contacts with three lower balls. The rolling contact fatigue (RCF) tests were performed under immersed lubricated conditions using two different lubricants. Fatigue failure modes were observed using a scanning electron microscope. Microhardness measurements of the coating and the substrate and elastohydrodynamic fluid film thickness results are included. The results show the requirement for significant optimization of the coating before use in rolling element bearing applications. The coating was fractured in a delamination mode. Test results show an optimization in coating process is required before these coatings can be used for rolling contact applications. WC-Co coatings perform better than Al 2O 3 coatings in rolling contact.

VIBRATIONS OF HYBRID CERAMIC BALL BEARINGS

Hybrid ceramic ball bearings with silicone nitride balls and steel rings were tested, and the vibration characteristics were compared with those of conventional steel ball bearings. In this study, two types of hybrid ceramic ball bearings and two types of conventional steel ball bearings were used as test bearings. The test bearings were operated under several rotational speeds and axial loads. The radial and the axial vibrations on the outer ring of each test bearing were detected by an accelerometer. The vibrations were examined by using an FFT analyzer. From the experimental results, analysis and discussion, the vibration characteristics of hybrid ceramic ball bearings, compared with those of conventional steel ball bearings, are explained.

Vibrations of Hybrid Ceramic Ball Bearings. 1st Report. Vibration Characteristics of Bearings under Axial Load.

The vibrations of hybrid ceramic ball bearings having steel rings and silicon nitride balls were investigated and compared with those of conventional steel ball bearings. The test ball bearings were operated at several speeds under axial loads. The radial and axial vibrations on the outer ring were monitored by an accelerometer. The vibrations were examined using a fast Fourier transform analyzer. From the experimental results and discussion, the following conclusions were obtained. ( 1 ) The overall values of vibratory velocity for hybrid ceramic ball bearings are higher than those of conventional steel ball bearings. ( 2 ) The peaks of radial and axial vibration of hybrid ceramic ball bearings appear in higher frequencies compared with the corresponding peaks of conventional steel ball bearings. ( 3 ) The peaks are caused by the radial natural vibrations of arbor, the in-plane natural vibrations and the out-of-plane natural vibrations of the outer ring.

The Performance of Ball Bearings With Silicon Nitride Ceramic Balls in High Speed Spindles for Machine Tools

Two types of angular contact ball bearings for machine tools having steel rings and silicon nitride balls were tested and the temperature rise was compared with that of conventional steel ball bearings with grease lubrication and oil-air lubrication as well. Experimental results indicated that the temperature rise of silicon nitride ball bearings was much lower than that of steel ball bearings at high speeds. Calculations made using a computer demonstrated that the reduction of gyroscopic moments and centrifugal forces acting on balls because of the low density of silicon nitride resulted in about 30 to 50 percent less frictional loss at high speeds even with low-cost lubrication such as grease or oil-air.

Diamond burnishing as a finishing and hardening operation

An experimental approach using a modified four-ball machine was used to investigate the rolling-contact fatigue (RCF) performance of tungsten carbide cobalt (WC-12%Co) coatings deposited by the high-velocity oxy-fuel (HVOF) process. The coated rolling-elements were in the geometrical shape of a cone which replaced the upper ball of the modified four-ball machine. The RCF tests simulate the configuration of a deep groove rolling-element ball bearing, and the tests were conducted in a conventional steel ball bearing and hybrid ceramic bearing configurations. The coating thickness, Hertz contact stress and the test lubricants were varied to provide various tribological conditions during the tests. Three different coating thicknesses were investigated and the coatings were ground and polished to attain a good surface finish on the rolling elements. The effect of substrate hardness, coating thickness and fluid film thickness on the RCF performance have been investigated along with the coating failure modes. Coating wear has been analysed using a scanning electron microscope (SEM) and the results discussed with the aid of the coating microstructure, microhardness and talysurf analysis of the wear track. Test results reveal that the performance of the coating is dependent upon the combination of the substrate and the coating properties. Moreover, the coating failure is a function of surface and subsurface mechanisms depending upon the tribological conditions during the test. Thinner coatings did not fail at the interface, indicating a good adhesive strength between the coating and the substrate. The depth of the failure and its comparison with the orthogonal shear-stress depth has been discussed. The coating failure was observed to be a combination of surface wear and subsurface delamination.