Cylindrical Roller Research Articles

Three-dimensional reconstruction of industrial parts from a single image

This study proposes an image-based three-dimensional (3D) vector reconstruction of industrial parts that can generate non-uniform rational B-splines (NURBS) surfaces with high fidelity and flexibility. The contributions of this study include three parts: first, a dataset of two-dimensional images is constructed for typical industrial parts, including hexagonal head bolts, cylindrical gears, shoulder rings, hexagonal nuts, and cylindrical roller bearings; second, a deep learning algorithm is developed for parameter extraction of 3D industrial parts, which can determine the final 3D parameters and pose information of the reconstructed model using two new nets, CAD-ClassNet and CAD-ReconNet; and finally, a 3D vector shape reconstruction of mechanical parts is presented to generate NURBS from the obtained shape parameters. The final reconstructed models show that the proposed approach is highly accurate, efficient, and practical.

Study of the effect of macrogeometry of rubbing steel bodies at their point contact on the tribological characteristics of lubricants under boundary lubrication conditions

The effect of the shape of contacting nonconformal elements of friction units that form an initial point contact on the tribological characteristics of lubricants during friction in the boundary lubrication mode. Point contact of rubbing bodies is realized on four-ball friction machines when testing tribological characteristics of lubricants in accordance with Russian GOST 9490–75 and GOST 23.221–84 Standards.However, these tests are carried out with the friction of standard bearing balls and does not allow taking into account the impact of materials of rubbing bodies on the results of the experiment. Therefore, two alternative designs of mandrels were developed, which allow implementation of two friction schemes: «rotating ball clamped in the spindle of the machine – three roller face planes» and «rotating ball — three cylindrical rollers». The load on the friction unit for both friction schemes, as well as in parallel on the mandrel under testing, in which three balls are installed, is the same (108 N), the spindle rotation speed is equal to 1 rpm, duration of testing is 60 min. The diameter of balls used in these experiments was 12.7 mm, and diameters of rollers were 5 and 8 mm, respectively. The material of samples was ShKh-15 tool steel or its 100Cr6 analogue. The designs of mandrels and the dimensions of samples were chosen in such a way that in all cases the contact areas of the experimental samples with the wearing (upper) ball would lie on a circle with a diameter of 7.32 mm. The tests were carried out under dry friction, and in boundary lubricated conditions in a PAO-4 polyalphaolefin oil medium, as well as in the same oil medium with the additives of oleic acid and DF-11 (a solution of zinc dialkyldithiophosphate in a low-viscosity oil). It is shown that the composition of a lubricating medium has a decisive effect on the test results (i.e., on the values of the friction coefficients and on the values of the areas of wear scars), while the geometry of the rubbing bodies, as well as the maximum Hertz stresses in the tribological contact, had a little effect on the antifriction and anti-wear characteristics of oils.

The effect of rotation rate and mass of wheel pairs on the result of vibration diagnostics of axle boxes using a UDP-2021 stand

Aim. The paper aims to compare the results of vibration diagnostics at different wheel pair (WP) rotation speeds based on the peak signal values and noise from the front bearing of the WP axle box equipped with a SOP AK 32.01 cylindrical roller with a standard defect. Methods. The peak vibration signal values were analysed using WP with different wheel tread thicknesses, i.e., 25, 45, and 65 mm. The bearing of one of the axle boxes (front) was equipped which a defective SOP AK 32.01 roller. Results. In the course of the experiment, it was found that as the thickness of the wheel tread grows the probability of over-rejection increases, which is practically confirmed by the fitness of the parts and components of the axle box upon dismantling and careful inspection. Conclusion. The “Reject” conclusion issued by the UDP-2001SM vibration stand should directly depend on the WP rotation speed. Additionally, its rotation rate should be selected depending on the thickness of the wheel tread.

Influence of micro-texture radial depth variations on the tribological and vibration characteristics of rolling bearings under starved lubrication

Surface micro-texturing involves creating microscopic pits or textures, serving as lubricant reservoirs to enhance lubrication distribution, potentially reducing friction and wear. This study specifically delves into the influence of varied depth patterns of pits on the operational performance of textured rolling bearings under severe lubrication conditions. Five distinct patterns with a fixed pit diameter (250 µm) and different depth variations (concave, decreasing, increasing, convex, and horizontal) were introduced on the shaft rings of cylindrical roller thrust bearings using the laser marking method. Wear tests were conducted under starved lubrication condition. Wear loss and signal analysis highlight the profound effect of depth variations, whereby bearings with shallow pits near the outer side of their working surfaces exhibit longer lubrication times, improved tribological performance, and enhanced vibration characteristics. Notably, the convex pattern stands out for providing comprehensive and favorable tribological and vibration properties. This research contributes valuable insights for the optimal design of micro-textures for rolling bearings, paving the way for enhanced efficiency and reliability in mechanical systems.

A multi-function integrated PVDF transducer for fault detection and speed measurement of cylindrical roller bearings

Monitoring the condition of bearings in rotating machinery is crucial to ensure reliability, safety, and efficiency. Recently, integrated sensors have become more popular than traditional accelerometers in bearing condition monitoring because of their compact design, cost-effectiveness, and improved efficiency in fault detection through a short transmission path. This study presents a new approach to bearing condition monitoring by developing a bearing with an integrated Polyvinylidene Fluoride transducer. This polymer-based transducer, known as PVDF, has a piezoelectric effect which generates electric charge in response to mechanical excitation. The PVDF transducer was selected for its high sensitivity, flexibility, and thin structure. The developed bearing with the integrated PVDF transducer can detect faults under constant and variable speeds, and the damage size can be estimated with an accuracy of 10%. It outperformed a commercial accelerometer in noisy environments with artificial impacts from an air motor, making it a highly reliable option for bearing condition monitoring in noisy industrial settings. The PVDF transducer can also be used as a low-cost speed sensor with an accuracy of 5.2%, offering a versatile solution for machine monitoring. By simultaneously recording rotational speed and vibration, the developed integrated transducer provides a comprehensive view of machine health and performance as a multi-function transducer, enabling more accurate and efficient maintenance scheduling.

Wear Reduction on the Roller–Shoe Mechanism at High Operation Loads

The roller–shoe mechanism is a classic mechanical assembly with an essential role in motion transmission. Common rail high-pressure pumps are an example of a complex assembly that uses such a mechanism to transform the rotation motion into a translation one. The rolling element of the mechanism is represented by a cylindrical roller. Although it can carry heavy loads due to its design, a proper surface profile could significantly increase the life of the entire mechanism. A better solution can be achieved using a logarithmic profile. The shoe is the second base element of the mechanism. It is a part with an inner cylindrical surface and it is separated from the roller by a thin lubricant film. Considering this, increasing the hardness of the roller–shoe contact surface can be obtained using a suitable coating. The positive results of this coating are highlighted using endurance tests to which high-pressure pumps are subjected. Therefore, the roller profile and the shoe coating represent two directions for improving the contact between the mechanism transmission elements, in terms of wear reduction. The purpose of this paper is to identify a suitable roller profile and to highlight its impact on the shoe coating.

Finite Element Analysis of Solid and Hollow Roller Bearings to Predict the Influence of Contact Factors on Cage Slip

This study examines the influence of contact factors such as bearing deformation, contact width and contact pressure on cage slide in cylindrical roller bearings. A cylindrical shaped roller bearing test setup is designed in order to determine the operating speed of bearing components under varying working circumstances. Solid and hollow roller bearings are analyzed using finite element technique, and the contact parameters are obtained. The cage slip obtained by experimental work is correlated with the contact parameters of hollow and solid shaped roller bearings. The specific load acting on solid rollers at various angular positions and the corresponding bearing deflection are obtained by FEA and the bearing run out is estimated. A new methodology is developed for deriving the contact mechanics of hollow roller to predict contact pressure and contact width from the roller deflection. The effect of hollowness on these parameters is derived and the corresponding cage slip is correlated. The effect of hollowness on bending and resultant stresses is obtained by numerical and analytical methods to correlate the stability of hollow roller bearing with the percentage of hollowness.

Statement of Retraction: Tribological Behavior for Vein-bionic Textured Cylindrical Roller Thrust Bearing System under Starved Lubrication

Statement of Retraction: Tribological Behavior for Vein-bionic Textured Cylindrical Roller Thrust Bearing System under Starved Lubrication

Unveiling Polychrome Printing Methods on Textiles: Preliminary Results from the Mariano Fortuny y Madrazo Collection in Venice

At the beginning of the 20th century, the eclectic artist Mariano Fortuny y Madrazo patented two innovative methods for polychrome printing on fabrics and textiles, giving life to Fortuny fabric production in Venice. The first patent was related to colour application, while the second to a special machine that allows continuous printing using cylindrical rollers. Despite the descriptions, the methodology and materials used remain a secret. In collaboration with the Fortuny Museum in Venice, this research aimed at studying and identifying the different steps of Fortuny printing methodologies. Printing matrices, fabrics and raw materials found in the artist’s studio were analysed in a multi-analytical campaign through digital microscopy, X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy in attenuated total reflectance (FTIR-ATR), μ-Raman spectroscopy and gas chromatography–mass spectrometry (GC–MS). Three main pigments were identified in paper samples: ivory black, a copper-based pigment, and a carbon black pigment with ultramarine for blues. The pigments were bound with linseed oil and colophony in varying proportions. Polychrome silk fabrics were dyed with a base colour, and then the coloured patterns were superimposed by continuous printing. Prussian blue was identified as one of the textile inks. Results provided a better understanding of printing methodology.

A fusion TFDAN-Based framework for rotating machinery fault diagnosis under noisy labels

Traditional fault diagnosis (FD) for rotating machinery solely based on vibration signals has problems such as inconvenient collection, low accuracy, and poor robustness. This article proposes a fusion framework based on tensor fusion and dual attention network (TFDAN), utilizing acoustic and vibration signals from two datasets of centrifugal pumps and cylindrical roller bearings. Firstly, continuous wavelet transform (CWT) is used to transform two original signals into two-dimensional time–frequency maps to highlight time–frequency features. Then, the images are fed into the fusion framework, where tensor fusion can construct the corresponding time–frequency maps of the working conditions into multi-channel datasets, enhancing the feature connections between acoustic and vibration signals. The dual attention network takes on the fused samples, extracts local features of the image using its positional attention module, and further aggregates feature correlations between channels using its channel attention mechanism. Finally, in order to simulate the actual production situation, different proportions of noisy labels are added to the dataset. In response to the impact of noisy labels, we incorporate an improved contrastive regularization function (ICRF) into the model, fully utilizing its advantage of preventing overfitting of noisy labels. The effectiveness of our proposed method has been demonstrated through two experimental cases. Compared with other methods, our method has better performance in terms of diagnostic accuracy and robustness to noisy labels.

Electrical Impedance Spectroscopy for Precise Film Thickness Assessment in Line Contacts

In this article, we focus on utilising electrical impedance spectroscopy (EIS) for the assessment of global and contact impedances in roller bearings. Our primary objective is to establish a quantitative prediction of lubricant film thickness in elasto-hydrodynamic lubrication (EHL) and investigate the impedance transition from ohmic to capacitive behaviour as the system shifts from boundary lubrication to EHL. To achieve this, we conduct measurements of electrical impedance, bearing and oil temperature, and frictional torque in a cylindrical roller thrust bearing (CRTB) subjected to pure axial loading across various rotational speeds and supply oil temperatures. The measured impedance data is analysed and translated into a quantitative measure of lubricant film thickness within the contacts using the impedance-based and capacitance-based methods. For EHL, we observe that the measured capacitance of the EHL contact deviates from the theoretical value based on a Hertzian contact shape by a factor ranging from 3 to 11, depending on rotational speed, load, and temperature. The translation of complex impedance values to film thickness, employing the impedance and capacitance method, is then compared with the analytically estimated film thickness using the Moes correlation, corrected for inlet shear heating effects. This comparison demonstrates a robust agreement within 2% for EHL film thickness measurement. Monitoring the bearing resistance and capacitance via EIS across rotational speeds clearly shows the transition from boundary to mixed lubrication as well as the transition from mixed lubrication to EHL. Finally, we have observed that monitoring the electrical impedance appears to have the potential to perform the run-in of bearings in a controlled way.

Vibration model combined with natural frequency characteristics of cylindrical roller bearings with spalling defects

The modeling of early spalling defects in cylindrical roller bearings (CRB) is a challenging problem in fault diagnosis. Due to the absence of prominent "drop-in" excitation, accurately describing the signal characteristics of the early failure mechanism model for CRBs becomes difficult. In this paper, the failure of cylindrical roller bearings due to spalling caused by fatigue is a frequent occurrence. The previous defect models have been centered on sharp-edge impact between the roller and spalling defects. However, they have not provided an adequate depiction of the variation in contact stiffness caused by roller-fault interaction. In this paper, a novel CRB vibration model that takes into account contact stiffness and natural frequency characteristics is proposed. The model considers both the load redistribution and contact stiffness variation caused by spalling defects. This new model provides a spring-damper system based on contact stiffness between the roller and raceway, enabling an estimation of the CRB system's natural frequency characteristics. The outer raceway spalling fault with varying sizes is simulated in this paper, taking into account spalling defect extents and load distribution. The vibration response of the fault signal model is investigated. The simulation results show that the load and contact stiffness will change as the roller passes through the defect zone. Furthermore, the statistical distribution of fault feature signals demonstrates the effects of contact stiffness variation on natural frequency characteristics. The experiments given in this paper have verified the simulation results of the proposed signal model.

Universal accuracy model for three different types of precision bearings with three basic structures under quasi-static conditions

A universal accuracy model is established under quasi-static conditions to predict motion accuracies and directly compare error averaging abilities among three different types of precision bearings (including fluid hydrostatic, porous air, and cylindrical roller bearings) with three basic structures (including linear (i.e., guideway), journal, and thrust bearing structures) used widely in precision and ultra-precision machine tools. To introduce the universal accuracy model, three types of precision guideways are taken as examples. Uniform generalized coordinate systems are used to evaluate error motions and uniform averaging coefficients are defined to assess error averaging abilities. It is found that the total error averaging abilities consist of basic and layout error averaging abilities characterized by corresponding averaging coefficients. The total averaging coefficients are the products of basic and layout averaging coefficients which are independent of each other. The porous air bearings have strongest basic error averaging abilities, followed by the fluid hydrostatic bearings, and finally followed by the cylindrical roller bearings. The layout averaging coefficients are related to the number and layout of pads or rollers which are working like some structural filters for a certain kind of error motion. A summary of accuracy experiments based on previous studies provides evidence of the existence of layout error averaging abilities. The content discussed in this paper is of significant importance for the selection and design of precision bearings.

Theoretical analysis of vibration characteristics of high-speed cylindrical roller bearing with groove elastic supports

As a necessary support system of high-speed rotor system, the roller bearing with elastic support’s vibration characteristics directly affect the stability and safety of rotor system. At this point, the theoretical analysis of bearing performance under the assumption of rigid ring is obviously no longer applicable. In this paper, considering the elastic deformation of both cylindrical roller bearing outer ring and the groove elastic support, the dynamic differential equations of cylindrical roller bearing with the elastic support are established on the basis of rolling bearing dynamics, and the bearing’s vibration under different working conditions is analyzed. The theoretical analysis results show that the groove elastic support can effectively reduce the radial vibration of cylindrical roller bearing under high speed and large radial load. And the experimental results show that the test’s vibration is consistent with the simulation’s vibration, which proves the reliability of the dynamic model of cylindrical roller bearing with the groove elastic support proposed in this paper. This research gives a new method for improving the dynamic characteristics of high-speed cylindrical roller bearings, and the model presented in this paper provides a theoretical basis for the design and manufacture of cylindrical roller bearing with elastic support.

Experimental and Theoretical Study on Forming Film Properties of Hollow Cylindrical Rollers

Bending deformation of a hollow cylindrical roller (HCR) was calculated by curve bending theory and slice technology. Furthermore, an elastohydrodynamic lubrication (EHL) model involving hollow rollers was established by coupling the finite line EHL model and bending deformation. Measurements of film thickness for hollow rollers were carried out by using a line-contact optical EHL test rig, and the experimental data and theoretical results agreed well with each other. For a roller with a straight-line profile, the hollow structure could reduce pressure peak at the roller ends, but the edge effect was still present. The film thickness at the ends unfortunately could not be improved by such hollow structures, unless a profile modification for the operating surface is designed.

Predictive Analytics-Based Methodology Supported by Wireless Monitoring for the Prognosis of Roller-Bearing Failure

Roller mills are commonly used in the production of mining derivatives, since one of their purposes is to reduce raw materials to very small sizes and to combine them. This research evaluates the mechanical condition of a mill containing four rollers, focusing on the largest cylindrical roller bearings as the main component that causes equipment failure. The objective of this work is to make a prognosis of when the overall vibrations would reach the maximum level allowed (2.5 IPS pk), thus enabling planned replacements, and achieving the maximum possible useful life in operation, without incurring unscheduled corrective maintenance and unexpected plant shutdown. Wireless sensors were used to capture vibration data and the ARIMA (Auto-Regressive Integrated Moving Average) and Holt–Winters methods were applied to forecast vibration behavior in the short term. Finally, the results demonstrate that the Holt–Winters model outperforms the ARIMA model in precision, allowing a 3-month prognosis without exceeding the established vibration limit.

Analysis and experimental research of transient temperature rise characteristics of high-speed cylindrical roller bearing

In this paper, on one hand, the time-varying characteristics of the heat source and thermal boundary conditions of the high-speed spindle system were analyzed considering the thermal-structural coupling effect. And a transient bearing temperature field prediction method combining the thermal network method and finite element method was proposed. Furthermore, the relationships between time step, calculation efficiency and calculation results were analyzed. On the other hand, a online real-time monitoring system of the transient temperature of the cylindrical roller bearing inner ring for maximum speed of 13,000 r/min was designed and implemented using fibre optic sensing technology. Comparing with the conventional static thermal analysis results, it is verified that the simulation method proposed in this paper has higher accuracy. This paper provides a new approach for analysing and testing the thermal characteristics of high-speed spindle system.

Efficient Strain Analysis of Radially Loaded Hollow Cylindrical Roller Using Symbolic Regression

Efficient Strain Analysis of Radially Loaded Hollow Cylindrical Roller Using Symbolic Regression

Finite element contact analysis of the hollow cylindrical roller bearings

Finite element contact analysis of the hollow cylindrical roller bearings

Mechanical Properties Analysis of Cylindrical Roller Bearings with Different Profiles under Combined Load

Abstract Rolling bearing is one of the core basic components of the aero-engine, which mainly undertakes the role of supporting the rotor and the corresponding parts and transferring the load. Considering the rotating effect and important error sources such as axial predeformation and radial clearance that may occur during the installation of cylindrical roller bearings, this paper establishes a four-degree-of-freedom static analysis model of cylindrical roller bearings based on Hertzian elastic contact theory and conducts a comparative study on the mechanical characteristics of aero-cylindrical roller bearings with different profiles. The results show that as the radial load increases, the radial displacement and stiffness of the roller bearing will increase, whereas the fatigue life of the bearing will gradually decrease. Compared with the external load, the rotating speed has less influence on the stiffness of roller bearings. In addition, the profile of rolling elements as a basic structural parameter of the bearing will also have a greater impact on the mechanical properties of the roller bearings, which should be designed and used in conjunction with the actual situation in engineering applications.