Search Results (10)

As high-speed railway systems continue to develop toward intelligent operation, axle box bearings integrated with sensors have become key components for real-time condition monitoring. However, introducing sensor-embedded slots disrupts the structural continuity and thermal conduction paths of traditional bearing rings. This results in localized stress concentrations and thermal distortion, which compromise the bearing’s overall performance and service life. This study focuses on a double-row tapered roller bearing used in axle boxes and develops a multi-physics finite element model incorporating the effects of sensor-embedded grooves, based on Hertzian contact theory and the Palmgren frictional heat model. Both contact load verification and thermo-mechanical coupling analysis were performed to evaluate the influence of two key design parameters—groove depth and arc length—on equivalent stress, temperature distribution, and thermo-mechanical coupling deformation. The results show that the embedded slot structure significantly alters the local thermodynamic response. Especially when the slot depth reaches a certain value, both stress and deformation due to thermo-mechanical effects exhibit obvious nonlinear escalation. During the design process, the length and depth of the arc-shaped embedded slot, among other parameters, should be strictly controlled. The study of the stress and temperature characteristics under the thermos-mechanical coupling effect of the axle box bearing is of crucial importance for the design of the intelligent bearing body structure and safety assessment. Full article

The intelligent bearing with an embedded sensor is a key technology to realize the running state monitoring of railway locomotive axle box bearings at the source end. To investigate the mechanical properties of axle box bearings with embedded sensor slots, based on nonlinear Hertzian contact theory and the bearing fatigue life theory, a mechanical equivalent analysis model with a virtual mandrel is established for double-row tapered roller bearings used in axle boxes with sensor-embedded slots, which integrally considers the effects of external forces. After verifying the mesh independence before and after embedding the sensor slots, the contact load of tapered rollers calculated by the mechanical model is compared with the theoretical solution based on Hertz contact which verifies the validity of the model from the perspective of contact load. The results show that adjusting the grooving depth and axial position has a significant effect on the local stress peak, and an excessive grooving depth or inappropriate axial position will trigger fatigue damage. This study provides a theoretical basis for analyzing the mechanical characteristics of sensor-embedded slots used in railway locomotive axle box bearings. Full article

The key to exploring the behavior of bearings through dynamic methods lies in establishing an accurate model for calculating the contact load between the roller and the raceway. Based on the half-space theory of Boussinesq, this study developed a full-order model for calculating the contact load of the finite line contact roller. The model adopted an iterative procedure to calculate the contact load of each roller slice according to deformations. According to the comparisons between the contact loads obtained by the proposed model and those obtained by FEA, the average error for a cylindrical roller was approximately 2%, while that for a tapered roller was approximately 17%. By neglecting the influences of inter-slice contact stresses on the deformation of local roller slice, a fast-calculating method for the full-order model was developed, thereby reducing the calculation time by approximately 77%. By integrating the fast method with the Dowson–Higginson’s formula, another model was developed to calculate the contact load under lubrication conditions. The proposed models were utilized to investigate the dynamic characteristics of a double-row tapered roller bearing, and the results were validated through experiments. The proposed method could be utilized to assess dynamic performances of bearings across different operating scenarios. Full article

A steady-state thermal model of double-row tapered roller bearings (DTRB) with grease lubrication under a combined load is established in this paper. The influence of the internal load distribution on the temperature allotment of bearings in the circumferential, axial, and radial directions is considered. Firstly, the local heat generation of the bearing is calculated based on the kinematic relationship inside the bearing, the internal load distribution, and the rheological properties of the grease. Then, combined with the heat dissipation analysis of the bearing, the three-dimensional steady-state temperature field of the DTRB is obtained. Ultimately, an analysis is conducted to examine how working conditions, including radial load, axial load, and rotational speed, impact the allotment of temperature fields in a DTRB along its circumferential, axial, and radial directions. The theoretical analysis outcome agrees with the experimental test outcome, providing theoretical guidance for the analysis of the bearing’s three-dimensional temperature field. Full article

Double-row tapered roller bearings have been widely used in various equipment recently due to their compact structure and ability to withstand large loads. The dynamic stiffness is composed of contact stiffness, oil film stiffness and support stiffness, and the contact stiffness has the most significant influence on the dynamic performance of the bearing. There are few studies on the contact stiffness of double-row tapered roller bearings. Firstly, the contact mechanics calculation model of double-row tapered roller bearing under composite loads has been established. On this basis, the influence of load distribution of double-row tapered roller bearing is analyzed, and the calculation model of contact stiffness of double-row tapered roller bearing is obtained according to the relationship between overall stiffness and local stiffness of bearing. Based on the established stiffness model, the influence of different working conditions on the contact stiffness of the bearing is simulated and analyzed, and the effects of radial load, axial load, bending moment load, speed, preload, and deflection angle on the contact stiffness of double row tapered roller bearings have been revealed. Finally, by comparing the results with Adams simulation results, the error is within 8%, which verifies the validity and accuracy of the proposed model and method. The research content of this paper provides theoretical support for the design of double-row tapered roller bearings and the identification of bearing performance parameters under complex loads. Full article

A three-dimensional vehicle-axle box bearing coupling model is established. The model can calculate the contact force in three directions and obtain the dynamic response of axle box bearing under the real vehicle running environment. The load distribution on the double row tapered roller bearing and the vehicle is analyzed, and the co-simulation is conducted by comprehensively considering the force transmission between vehicle and bearing. Taking into account the great impact of defects on the bearing, three different types of bearing defects are added into the model, respectively. The simulation results verify the effectiveness of the model. The model is also verified by using the rolling and vibrating test rig of single wheelset. It is concluded that the simulation results show good agreement with experimental results. The influence of track irregularity on the system motion state is studied by using axis trajectory and vibration RMS (Root Mean Square value). The results show that the influence of track irregularity and wheel flat scar on axle box bearing cannot be ignored. The RMS of acceleration will change greatly due to the existence of defects. Wheel flat scar will greatly interfere with the extraction of bearing defect, but it can be selected at high speed and low frequency to monitor the existence of wheel flat scar, and select low speed and high frequency to monitor the existence of bearing defect. The research results are helpful to the detection of wheel flat scar and axle box bearing defect. Full article

The research on the thermal characteristics of railway double-row tapered roller bearing is of great significance for its structural design and operation monitoring. We established the quasi-static mechanical model of the bearing according to the test conditions, and we obtained the load distribution and kinematic parameters of the bearing. We studied the temperature distribution of railway double-row tapered roller bearing under test conditions through finite element analysis, which was consistent with the test results. We built a bearing testbed to study the effects of different rotating speeds on the temperature distribution of the bearing inner ring, outer ring, and roller. The results show that the speed dramatically affects the bearing inner ring. With the rate increase, the temperature difference between the inner and outer rings decreases gradually, and the temperature at the large end of the roller is the highest. Full article

With the continuous improvement of train speeds, it is necessary to find the possible problems of bearings in time, otherwise they will cause serious consequences. Aiming at the characteristics of rapid temperature change of bearings, a thin film thermocouple temperature sensor was developed to measure the real-time temperature of the bearing’s rolling elements during train operation. Using dc pulse magnetron sputtering technology, Al₂O₃ film, NiCr film, NiSi film, and SiO₂ film were successively deposited on an aluminum alloy substrate. We studied their microstructure, static characteristics, dynamic characteristics, and repeatability. Finally, we installed an adaptive film temperature sensor on the bearing testing machine to measure the temperature of the rolling elements. The results show that the developed temperature sensor has good linearity in the range of 30~180 ℃. The Seebeck coefficient is 40.69 μV/℃, the nonlinear fitting error is less than 0.29%, the maximum repeatability error is less than 4.55%, and the dynamic response time is 1.42 μs. The temperature of the measured rolling elements is 6~10 ℃ higher than that of the outer ring, which can reflect the actual temperature of the bearing operation. Full article

In this study, two-row tapered roller bearings (TBR) with different rib structures were tested under the condition of loss of lubrication. It was found that the double-row TBR with outer ring rib structure worked normally after 40 min of the test, but the inner ring The bearing of the side structure has failed. In order to explain this phenomenon, computational fluid dynamics (CFD) numerical simulation models of two structural bearings were established, and the flow characteristics of the oil in the bearing cavity under the conditions of full lubrication and loss of lubrication were studied by the method of discrete inlet oil volume. The research results show that, in the fully lubricated state, the oil volume fraction of the double-row TBR outer ring wall of the outer ring rib structure is 11.296 times higher than that of the inner ring rib structure. Moreover, the volume fraction of oil on the roller surface is 2.07 times higher in the outer ring rib structure than the inner ring rib structure. The volume fraction of lubricating oil in the bearing cavity decreases as the speed increases; however, the double-row TBR with the outer ring rib structure still shows a better lubrication effect than the inner ring rib structure. In the final stage of the loss of lubrication, the volume fraction of the bearing flow field of the outer ring rib structure is twice that of the inner ring rib structure, making the outer ring rib structure double-row tapered roller bearing (TBR) more dry Operational ability. Full article

In the case of double row tapered roller bearings, the windows found in bearing cages could be obtained using various machining methods. Some such machining methods are based on the cold forming process. There are many factors that are able to affect the machining accuracy of the windows that exist in bearing cages. On the dimensional precision of windows, the clearance between punches and die, the work stroke length, and the workpiece thickness could exert influence. To evaluate this influence, experimental research was developed taking into consideration the height and the length of the cage window and the distance between the contact elements of the cage. By mathematical processing of the experimental results, empirical mathematical models were determined and analyzed. The empirical models highlighted the intensity of the influence exerted by the considered forming process input factors on the dimensional precision of the windows obtained in bearing cages. Full article