Conical Rollers Research Articles

The next-generation of metaverse embodiment interaction devices: A self-powered sensing smart monitoring system

Wearable electronic devices collect user data to provide personalized experiences and real time interactions for the metaverse, thereby driving its development. This paper introduces an innovative self-powered sensing smart monitoring system (SSSMS) designed to harvest human low-frequency inertial energy and achieve gait recognition and fall monitoring (GR-FM) capabilities. The SSSMS enhances energy harvesting efficiency through Halbach electromagnetic enhancement mechanisms, achieving self-sustainability. Additionally, the conical roller triboelectric nanosensor (CR-TENS) accurately captures various human gaits, transmitting these states in the form of electrical signals to a computer via OpenBCI in real time. These signals are integrated with a deep learning-driven diagnostic module to achieve GR-FM. The experimental results demonstrate that under optimal external excitation, the output power is 2.27 mW, with a power density of 32 W/m3. After 100,000 cycles, both the EMG and CR-TENS modules still maintain good performance, sufficiently providing stable and continuous charging for the battery and offering a stable signal for signal processing. Both the EMG and CR-TENS modules exhibit robust feature capture capabilities, effectively sensing different excitation frequencies, amplitudes, and gait patterns. The SSSMS based on the GRU deep learning model achieves recognition accuracies of 96.13 %, 96.60 %, and 92.22 % for frequency, amplitude, and gait, respectively. Deployment experiments demonstrate high accuracy and sensitivity in frequency, amplitude, gait recognition, and fall monitoring, highlighting the advantageous design of EMG and CR-TENS for perceiving subtle motion state changes. The SSSMS demonstrates outstanding capabilities in self-sustainability and real time user embodiment information capture, showcasing its potential as a next-generation interaction device for the metaverse.

Research on Multi-Parameter Optimization of Conical Roller Line Processing Technology Based on Satisfaction Function

In the process of conical roller line processing, there will be problems such as low precision of processing parameters, long processing time, low utilization rate of machine tools, high rejection rate, and high processing cost, which will lead to low production efficiency. In order to solve this problem, it is necessary to iteratively optimize the size parameters, including inner diameter, ovality, and taper. By obtaining the optimal parameter combination, the size parameters in the production process are kept consistent, that is, the accuracy and performance of the workpiece during the processing are guaranteed so as to avoid the problem of quality difference, improve the production efficiency and reduce the processing cost. In view of the fact that there are often some constraints on the accuracy and efficiency in the machining process of tapered roller lines, how to optimize the parameters affecting the accuracy and the parameters affecting the efficiency to achieve balance between accuracy and efficiency in order to better meet the needs of customers for multi-objective optimization of the machining process has become the focus of research. Based on the existing research, this paper explores the multi-parameter optimization modeling and application in the machining process of tapered roller lines by constructing a satisfaction function, and then uses a genetic algorithm to iteratively search for the optimal solution by simulating natural selection and the genetic mechanism. Based on Python software v3.12, the production process of tapered roller bearings is simulated. The AHP analytic hierarchy process and CRITIC weight method are used to redistribute the parameter weights respectively. After eight iterations, it is concluded that the weight value assigned by the AHP analytic hierarchy process makes the satisfaction function value reach the best value of 0.99795 and tend to converge stably. The optimized parameter configuration significantly improves the machining accuracy and production efficiency of the tapered roller line. The optimal parameter combination is obtained: inner diameter: 9.9982 mm, ovality: 0.7 mm, taper: 0.5 degrees, production efficiency: 101.0.97 piece/h. In order to verify the optimization effect, the single value (X) and moving extreme difference (Rs) control charts in the measurement value control chart are used to analyze and verify the tolerance values of important parameters in the processing technology of the tapered roller line. The results show that the data points are all within the control limit, indicating that the processing process is in a statistical control state.

Efficient formability in Radial-Shear Rolling of A2024 aluminum alloy with screw rollers

The Radial-Shear Rolling (RSR) process, commonly utilizing traditional conical rollers, encounters challenges in achieving optimal deformation in high-strength aluminum alloy A2024, vital for aerospace applications due to its exceptional strength-to-weight ratio. This study explores the potential of screw rollers to enhance RSR efficiency for A2024 aluminum, aiming to evaluate their impact on microstructure, mechanical properties, and key deformation parameters (force, temperature) compared to conical rollers. Employing a combined approach of finite element simulations and experiments with force analysis, the study assesses the effects of screw rollers in a two-pass RSR process. The findings reveal significant advantages with screw rollers, achieving a 15 % increase in equivalent strain compared to conical rollers, indicating enhanced material formability. Consistent temperature distribution across roller types ensures stable processing conditions. Screw rollers also demonstrate a 9 % reduction in force required during the second rolling pass, potentially reducing equipment load demands and enabling higher compression per pass for improved process efficiency. Additionally, a more uniform microhardness distribution suggests consistent mechanical properties with screw rollers compared to conical ones. These results highlight the potential of screw rollers to optimize RSR of A2024 aluminum, offering improved plastic deformation efficiency, temperature control, and potentially lower equipment loads. This advancement holds promise for a more efficient and cost-effective RSR process in producing high-quality A2024 aluminum components for aerospace and other demanding applications.

Влияние микрогеометрических параметров сферической поверхности ролика на звуковое давление и вибрацию подшипника

In a production environment of JSC UPC Volzhsky it is shown how to increase the vibration discharge of bearings with conical rollers due to the use of rollers with the specified microgeometric parameters of the spherical surface made in the general production flow. The sphere is formed under the combination of rough grinding, finish grinding and final grinding using an assembled abrasive tool consisting of three rolls of various characteristics. It was found that in a bearing, with sequential replacement of rollers, where sphere roughness varies in the range of 0.10 Ra ≤ 0,.20 microns for rollers with roughness Ra ≤ 0,10 microns, the average value of the microgeometric parameters of the roller sphere in bearings (Ra, undulation W, deviation of circularity Δ) decreases by 2,4 – 4,3 times. The impact assessment of bearing rollers set having different parameters of the microgeometry of the spherical roller end on the sound pressure and vibration of the bearing was carried out. It was found that with an increase in the number of rollers with microgeometric parameters of the sphere closer to the lower edge of the tolerance field, the values of the overall vibration level, the vibration level in the third frequency band and the sound pressure level of the bearing improved. A statistical analysis of these parameters was carried out. The significance of the analyzed factors and conditions for increasing the vibration discharge of the bearing while ensuring processing modes within the framework of the current technological process are determined. Correlation and functional relationships between the average values of the microgeometric parameters of rollers spheres in bearings and the parameters of sound pressure and vibration were found.

Novel fabric-based 3D photothermal evaporator with advanced light-harvesting and thermal management design

Interfacial photothermal evaporation offers a promising and cost-effective method of obtaining freshwater. Traditional photothermal evaporators, when exposed to sunlight, typically have a heating region on their surface with temperature higher than room temperature. This can lead to thermal radiation loss and reduce evaporation efficiency. Therefore, this study presents an innovative design and fabrication of a fabric-based conical roll (FCR) evaporator, which enables low-temperature evaporation without a distinct heating region and facilitates the reversal of the thermal radiation path. In particular, the FCR-7.5-45 evaporator demonstrated remarkable performance even under 2.0 sun illumination, showcasing its advanced light-harvesting capability and excellent thermal management ability attributable to the conical spiral groove structure. The unique cold evaporation surface of the 3D evaporators, combined with this design, resulted in a high evaporation efficiency of 151.53 % and a rapid evaporation rate of 3.47 kg·m−2·h−1 under 1.0 sun illumination. Furthermore, the freshwater produced by the FCR evaporator met the drinking water standards set by international regulatory bodies. This indicates that the photothermal evaporator developed in this project holds great potential for widespread application in desalination and sewage treatment.

SUBSTANTIATION OF INDUCTION HEATING DURING FLANGING OF TUBULAR WORKPIECES BY ROLLING FORMING

Rolling forming (RF) processes are among the most efficient methods of metal forming. The required profile of the workpiece in rolling processes is formed by local deformation with conical or cylindrical rolls using sound technological schemes. When roll forming pipe billets with a ratio of the height of the initial deformed part to the wall thickness of more than 2.5, the flange seating process is made impossible by the loss of billet stability with subsequent fold formation. This phenomenon makes it impossible to produce wide flanges by drawing. To form workpieces with particularly wide flanges, we have developed a flanging method by rolling stamping. The essence of the flanging method is that at the initial stages of rolling, the top of the conical roll is shifted in the direction of the contact patch. At intermediate stages, to prevent the workpiece wall from turning inside out, the top of the roll is shifted in the opposite direction (along the workpiece axis). The main technological constraints are imposed by the insufficient ductility of the billet material, which can cause fracture. To develop the flanging processes in a reasonable manner, we studied the mechanics of outer flange deformation and methods of controlling material flow. The stress-strain state (SSS) of the material was analyzed using the hardness measurement method and the mesh method. The nature of the change in the stress-strain state in the most dangerous zones of the workpiece was determined, depending on the ratio of the flange diameter to the initial workpiece. Based on the experimental results, a mathematical model of the deformation trajectory of material particles of the outer surface of the flange in the coordinates of deformation intensity - an indicator of the stress state - was constructed. To assess the deformability of the material, a damage summation model with a power law approximation of the damage function was used. The model allows us to determine the ultimate fracture dimensions of the flange, as well as the plasticity resource used at intermediate stages. The condition for the suitability of metals for flanging by rolling stamping for engineering calculations is obtained. The necessity of applying induction heating in the processes of culling by rolling stamping is substantiated. This makes it possible to expand the technological capabilities of flanging processes by developing and using induction heating of workpieces, due to an increase in the plasticity characteristics and a decrease in the strength characteristics of metals in the process of deformation.

Substantiation of the parameters of the rotary ripper of the machine for pre-seeding treatment of ridges

Taking into account the fact that the ridge technology of cultivating crops is becoming widespread in the country, and there are no special technical means for pre-sowing treatment, a machine has been developed for processing ridges along their entire profile in one pass, consisting of a frame and support wheels mounted on it, lancet paws, rotary rippers and slatted rollers. The article presents the results of theoretical and experimental studies to substantiate the parameters of the rotary cultivator of the developed machine. According to the results of the research, it was found that for the qualitative implementation of the technological process of processing the slopes of the ridges and ensuring the required quality of soil crumbling on them, the length of the bar of the rotary cultivator must be at least 320 mm, the small and large diameters of its conical rollers, respectively, within 200-250 mm and 400- 450 mm, the number of its slats is 12-14 pieces, the width of the slats is 30-32 mm, as well as the vertical load on it in the range of 0.50-0.60 kN, the longitudinal distance between the lancet share and the rotary ripper is 60 cm .

Mathematical modeling on a novel manufacturing method for roller-gear cams using a whirl-machining process

The whirl-machining process is a precise, efficient, and promising machine process for manufacturing workpieces over the milling process. At the same time, the roller-gear cam has advantages over the other cam-follower system. However, the whirl-machining process has not been applied to manufacture the roller-gear cam. Therefore, this paper proposes a novel method for roller-gear cam manufacturing using a whirl-machining process. Mathematical modeling is described for generating the roller-gear cam, roller, and whirl-milling tool surface. A novel CNC machine and its coordinate system are proposed. Cutting simulations for obtaining the surface topologies and normal deviations are conducted. Globoidal cam with different cylindrical rollers, globoidal cam with a conical roller, and cylindrical cam with a conical roller are taken as case studies, and results are discussed. A virtual cutting simulation was conducted using VERICUT. Some machining examples are shown to verify the benefits of the proposed method in roller-gear cam manufacturing.

Влияние экономических санкций на производство и ремонт инновационных вагонов

Economic sanctions against the railcar building and repair industries have affected the production of cassette bearings of axle boxes used in the production and repair of innovative railcars. Cassette bearings have a number of significant advantages (unique abilities of conical rolling bodies, compactness, small size and others) that allow to realize loads from the axle to the rails of 245 kN (25 tf) or more and thereby increase the gross weight of railway cars to 108 tf. Withdrawal of manufacturers producing bearings from the Russian market (Timken, SKF, Brenko) led to a sharp drop in the production and repair of innovative rail-cars. A comparison of the production volumes of rail-cars in February and May 2022 discovered that there was a significant reduction (at JSC «Uralvagonzavod» and JSC «Tikhvin Railway Car Building Plant»), and by August production had practically stopped. The sanctions forced companies producing bearings (EPK-Brenko, Tek-Com Production) and railcar repair companies to search for new suppliers of components, primarily bearings. Such supplier companies could be Wafangdian (ZWZ), Luoyang LYC (China) and SPZ Bearings (Uzbekistan). As a result of the measures taken and the significant intensification of work, it is assumed that a significant part of the demand for bearings will be covered by domestic plants. The sanctions intensified the refinement and stimulated the production of twincylindrical roller bearings, which, according to preliminary test results, demonstrated the same durability resources as conical cassette bearings (eight years of operation and 800 thousand km of mileage). The paper analyzes and presents the statistics of the production of domestic railcars equipped with cassette-type bearings, and the challenges associated with their production.

Study of the influence of technological parameters on the mechanics of shaping of billets using roll stamping processes

The article presents the results of development and research of technological schemes of planting flanges on tubular (ring) workpieces by stamping by rolling cylindrical and conical rolls. It is shown that the achievement of significant dimensions of the various elements of the workpiece is possible by providing a directed flow of metal by changing the relative position of the roll and the workpiece. Planting of external flanges is one of the most effective operations of stamping by rolling, as it allows you to form a wide range of products with advanced geometric elements. To assess the technological capabilities of the flange landing operation, the most dangerous from the destruction positions of the workpiece zone was identified and the analysis of the stress strain state of the material using the method of grids, hardness measurement and microstructural analysis. According to the results of the research, the ways of deformation of the particles of the material of the peripheral surface of the flange in the coordinates "intensity of deformations - an indicator of the stress state" are schematically constructed. These deformation paths are given against the background of curves of ultimate deformations of steels, which are built on the results of uniaxial compression and torsion of cylindrical specimens and using tested approximations. A mathematical model of deformation trajectories is constructed, for which a one-parameter function is taken as a basis, which is "glued" from the elementary function of the sine and tangent to it at some point in the line. To determine the used plasticity resource, a damage summation model with a power approximation of the damage function was adopted. As a result, we have for the first time described the general expression of the linear damage summation model for the case of the parametric deformation path problem. The graphical representation on the constructed model of accumulation of damages in material of a dangerous zone of a flange at landing by a method of rolling stamping (SHO) is resulted. Based on the constructed model, it is possible to model the accumulation of damage by changing the values of the model parameters for different materials and deformation paths, which, in turn, depend on the relative geometric parameters of the workpiece and its location relative to the rolling roll.

EVALUATION OF DEFORMABILITY OF MATERIAL DURING PLANTING OF ELEMENTS OF PREPARATIONS BY ROLLING STAMPING METHOD

The article presents the results of development and research of technological schemes of planting flanges on tubular (ring) workpieces by stamping by rolling cylindrical and conical rolls. It is shown that the achievement of significant dimensions of the various elements of the workpiece is possible by providing a directed flow of metal by changing the relative position of the roll and the workpiece. Planting of external flanges is one of the most effective operations of stamping by rolling, as it allows you to form a wide range of products with advanced geometric elements. To assess the technological capabilities of the flange landing operation, the most dangerous from the destruction positions of the workpiece zone was identified and the analysis of the stress-strain state of the material using the method of grids, hardness measurement and microstructural analysis. According to the results of the research, the ways of deformation of the particles of the material of the peripheral surface of the flange in the coordinates "intensity of deformations - an indicator of the stress state" are schematically constructed. These deformation paths are given against the background of curves of ultimate deformations of steels, which are built on the results of uniaxial compression and torsion of cylindrical specimens and using tested approximations. A mathematical model of deformation trajectories is constructed, for which a one-parameter function is taken as a basis, which is "glued" from the elementary function of the sine and tangent to it at some point in the line. To determine the used plasticity resource, a damage summation model with a power approximation of the damage function was adopted. As a result, we have for the first time described the general expression of the linear damage summation model for the case of the parametric deformation path problem. The graphical representation on the constructed model of accumulation of damages in material of a dangerous zone of a flange at landing by a method of SHO is resulted. Based on the constructed model, it is possible to model the accumulation of damage by changing the values of the model parameters for different materials and deformation paths, which, in turn, depend on the relative geometric parameters of the workpiece and its location relative to the rolling roll.

EVALUATION OF DEFORMABILITY OF MATERIAL OF PREPARATIONS IN DIRECT AND REVERSE EXTRACTION BY ROLLING STAMPING METHOD

The article presents the results of development and research of various technological schemes of the process of stamping by rolling cylindrical and conical rolls to obtain complex profile workpieces. It is shown that the achievement of significant dimensions of the various elements of the workpiece is possible by providing a directed flow of metal by changing the relative position of the roll and the workpiece. The most effective rolling operations are landing, settling, unloading, reverse and direct extrusion. The paper focuses on the analysis of operations of reverse and direct extrusion to obtain complex profile blanks with developed, including thin-walled elements. Since the technological capabilities depend on the deformability of the material, the analysis of the stress-strain state of the workpieces was performed using the method of grids, hardness measurement and microstructural analysis. The main result of the analysis was the construction of ways to deform the particles of the workpiece material in the coordinates "deformation intensity - stress index". Zones of blanks that are deformed in the conditions of "rigid" stress state are established, therefore for these zones the deformability of metals was assessed using the criteria of phenomenological theory. In addition, the assessment of deformability was also performed for areas with the maximum degree of deformation of the material. The manufacture of thin-walled elements of the workpiece, using the operation of reverse extrusion, is accompanied by the appearance of significant contact stresses. To prevent the roll from being pushed out of the workpiece and forming elements with a constant thickness, support rollers should be provided. In the case of direct extrusion, the increase in contact stresses requires the application of additional measures to increase the strength of the tool.

DEVELOPMENT OF UNIVERSAL MATHEMATICAL MODEL FOR CALCULATION OF THE GEOMETRICAL PARAMETERS OF DEFORMATION ZONE DURING TUBE ROLLING USING PIERCING MILLS WITH CUP-SHAPED, BARREL TYPE AND CONICAL ROLLERS

The piercing mill parameters directly influence on the quality of pipes. In piercing mills, the process or setting parameters are the distance between rolls, rulers or guiding tools, mandrel extension, feed angle, rolling angle, etc. The geometrical parameters of deformation zone depend on the parameters of piercing mill. Non-optimal setting param-eters of the piercing mill result in defects such as external and internal slabs. The accurate technological parameters of piercing process are needed to define the setting parameters of the piercing mill. There are numerous numbers of math models and methods to calculate the technological parameters, but all of them were developed for one specific type of piercing mill rollers. Taking into consideration all of the disadvantages of the existing math models, the new mathematical model has been developed to define technological parameters of piercing process. The main purpose of the math model is to calculate the technological parameters of piercing mill with barrel type, conical and cup-shaped rollers. The ad-vantages of the math model comparison to the existing models are flexibility, a capability to define the parameters of all 
 three types of the rollers and high accuracy. The model shows high accuracy even with high angle of rotation and the incline of the rollers up to 45°. The main idea of the model is to define the shortest distance between the rolling axes and the surface of rollers. The results have been evaluated using the CAD software program KOMPAS 3D for all three types of rollers of piercing mill. According to the results of comparison, the identities are equal to 100% for all three types of rollers.

Substantiation of the Density of the Soil Formed by a Ridge Drill Roller

A method is presented for determining the density of soil in the ridge from the simultaneous action of spherical disks and a conical roller wheel. Heuristic and technical analysis of the process of forming soil ridges by rollers made it possible to conclude with a 90 % reliability that the main factorsб which significantly affect the quality of soil ridge formation, are the angle of attack of spherical discs (α = 10°), the speed of the roller (vс = 5.4 km / h) and the compression force of its spring (Fspr. = 180 N).

Study of the rollers geometry effects in rotary tube piercing and wear analyses of mandrel according to the finite element method

The rotary tube piercing (RTP) is the first process of making the seamless tube after producing the desired alloy ingot. There are several approaches to manufacture a seamless tube, but one of the most common types is RTP. This approach covers a wide range of processes that are categorized according to the number and shape of the rollers. On the other hand, each of these types has designed guides in the output and input of the piercing process. In this paper, a new design of the input guide for four types of rollers have been examined and simulated. Thus, four specimens including Diescher and Conical rollers were considered, with the different number of rollers. Results including torque, total force, mandrel wear, temperature distribution, and strain were extracted using FEM simulation. In order to the validation of simulation, the total force and oscillations of applied force within the process have been compared with the experimental results. The results obtained through this simulation, are more in line with the empirical results obtained from previous research. As well as, the FEM simulation confirmed the performance accuracy of the output and input guides of the RTP process. On the other hand, the results indicate that the three-roller Diescher type with 17° feed angle, has the most suitable arrangement for production of seamless tube.

Analysis of the tube piercing process types in terms of final product properties

The rotary tube piercing (RTP) is the first process of making seamless tube after producing the desired alloy ingot. There are several ways to make a seamless tube, one of the most common being RTP. This approach covers a wide range of processes that are categorized according to the number and shape of the rollers. On the other hand, each of these types has designed guides in the output and input of the piercing process. In this article, a new design of input and output guide for all types of rollers have been examined and simulated. Thus, three specimens including Diescher and Conical rollers were considered with 3 and 2 numbers, respectively. Results including torque, total force, temperature distribution and strain were extracted using FEM simulation. The results obtained through simulation are more in line with the experimental results obtained from previous research. While showing the successful performance of the output and input guides of the RTP process, the results indicate that the 3-roller Diescher type RTP has the most suitable arrangement for seamless tube production.

DEVELOPMENT OF TECHNOLOGICAL PROCESS OF FORMATION OF WIDE FLANGES ON SHEET PROCUREMENTS BY ROLLING STAMPING METHOD

The article presents the results of development and research of the technological process of forming wide outer flanges of lids of malt and distillation columns on sheet blanks by rolling stamping. For this purpose, equipment has been developed in the form of a rolling device for a lathe and an autonomous rolling unit, which allow to form the outer flanges with a conical roll. The rolling unit to the lathe provides the presence of coil springs for pressing the roll to the workpiece with the mandrel. Both settings provide the ability to change the angle of the axis of the rolling unit relative to the axis of the mandrel with the workpiece. Studies have shown that the technological capabilities of the process are limited by the corrugation of the flange wall. The power calculation of flanging of external flanges by a conical roll by the SHO method is carried out and formulas for determination of deformation forces are received. The acceptable accuracy of these formulas has been experimentally confirmed, and there is a tendency to increase the error with increasing geometric dimensions of the workpiece. To assess and expand the technological capabilities of the process, an analysis of the formation and deformed state of the workpieces. Since the main danger in the formation of external flanges by the SHO method is the loss of stability in the form of corrugations, the paper obtained an expression for determining the maximum width of the flange under the condition of a stable process. If it is necessary to obtain more developed flanges, it is proposed in the second stage to provide thinning of their wall by drawing with the use, if necessary, heating the workpiece by induction method.

DEVELOPMENT OF THE COMBINED TECHNOLOGICAL PROCESS OF BLANK STACKS FLANGES FORMATION BY THE METHOD OF STAMPING BY ROLLING AND ROTARY DRAWING

The article presents the results of the development and research of the combined technological process of forming the outer and inner flanges of the lids of fractional and distillation columns on sheet blanks by the method of stamping by rolling and rotary drawing. For this purpose, equipment has been developed that allows to form both outer and inner flanges of the blank in one run of the conical roll. Studies have shown that technological capabilities of the process are limited by the risk of destruction of the top layers of the outer flange bending center and its corrugation, as well as by the neck formation or destruction of the peripheral areas of the inner flange. To assess the deformability of the outer flange, the stress-strain state of its bending center was investigated. According to the set stress values, the stress state of the material is determined, the maximum value of which on the surface of the bending zone is Formula for determining the minimum radius of the mandrel, which when using the values of the critical ductility of the material allows to prevent destruction. As well, an expression for determining the maximum width of the flange, provided that the destruction of peripheral areas is prevented, is obtained. As corrugations formation is the main danger in forming the external flanges by the stamping by rolling method (SR), the expression for determining the maximum width of the flange under the condition of a stable process is obtained. If it is necessary to get more developed flanges, it is proposed to provide thinning of their walls by rotary extraction at the second stage. When forming the inner flanges of the blank stacks radial compressive stresses and tangential tensile stresses in the material are brought about. The action of tangential stresses causes loss of stability of the flange by way of neck formation. The value of the critical strains increases with the approach to the state of plain-strain deformation. Therefore, it is recommended to develop process parameters based on construction of the critical strains diagrams.

Improving the thermal method for assessing the technical condition of rolling bearings based on the heating rate criterion

An improved method of passive thermal control has been proposed in order to operatively assess the technical condition of rolling bearings, based on studying the heating rate of a bearing. The values of the heating rate of ball, roller, and conical rolling bearings, as well as ball separators, have been determined empirically. It has been shown that the discrete limit heating rate values derived under the regular heating mode of mechanical reducers during stand tests are suitable for use as a diagnostic criterion for rolling bearings. Based on the heating speed criterion for mechanical reducers, it is possible to perform an operative assessment of the technical condition of rolling bearings of different types during the operation of equipment for different purposes. It has been established that for a rolling bearing in a working technical condition the heating rate under a regular heating mode does not exceed 1 °C/min. The resulting value corresponds to the diagnostic criterion for the heating rate of mechanical reducers in a working technical condition of ϑ н ≤1.1 °C/min. Using a diagnostic parameter of the heating rate under a regular heating mode makes it possible to resolve the issue related to the duration of control over the technical condition of a rolling bearing using a thermal method. Reducing the control procedure duration, when using the improved thermal non-destructive testing, by 4 times, would yield a reduction in operating costs due to the possibility of ongoing control over rolling bearings at the beginning of the equipment operation. It has also been confirmed that the heating rate of rolling bearings under a regular heating mode directly depends on their technical condition and does not depend on the load transferred and the mode of operation of the bearing nodes of the technological equipment. The proposed method could be applied in the maintenance system based on the actual condition of the equipment for the operative control over rolling bearings

Study on bearing stiffness characteristics with residual stress in carburized layer

In this study, a layering method of carburized ring is presented. A finite element (FE) model for analyzing bearing stiffness characteristics is established considering the residual stress in the carburized layer. The residual stress in the carburized layer of a double-row conical roller bearing is tested and the influence of the distribution of residual stress in carburized layer on the bearing stiffness is investigated. Results show that the residual stress in the carburized layer increases the contact stiffness of the bearing by 5% in the low-load zone and 3% in the high-load zone. The radial stiffness of the bearing is increased by 5% in the low-load zone and 3% in the high-load zone. The axial stiffness is increased by 6%, and the angular stiffness increased by 4%. The larger the thickness of the carburized layer, the greater the residual compressive stress in the carburized layer, the deeper the position of the maximum residual stresses in the carburized layer will lead to the greater stiffness of the bearing.