Browse Topic: Bearings

Items (3,130)
Roller bearings are used in many rotating power transmission systems in the automotive industry. During the assembly process of the power transmission system, some types of roller bearings (e.g., tapered roller bearings) require a compressive preload force. Those bearings' rolling resistance and lifespan strongly depend on the preload set during the installation process. Therefore, accurate preload setting can improve bearing efficiency, increase bearing lifespan, and reduce maintenance costs over the life of the vehicle. A new method for bearing preload measurement has shown potential for high accuracy and fast cycle time using the frequency response characteristics of the power transmission system. One open problem is the design of the production controller, which relies on a detailed sensitivity study of the system frequency response to changes in the bearing and system design parameters. Recently, an analytical model was developed for multi-row tapered roller bearings that includes
Gruzwalski, DavidMynderse, James
Hydrogen fuel cell is one of paths to achieve carbon neutrality transportation. In the last two decades, significant improvements have been made in compactness, efficiency and durability of fuel cell systems. For heavy duty truck applications, a life span similar to heavy duty diesel engines is required. As a critical component in the fuel cell system, air compressors play an important role to meet fuel cell systems’ high efficiency and durability requirements. In this paper, a holistic approach has been taken to develop a series of airfoil bearing centrifugal compressors for a wide range of applications from forklift, passenger vehicles to commercial vehicles, and achieve high efficiency and durability of one million start-stops. In the new platform development, cooling circuit was optimized so that the external cooling air circuit for the rotor and air bearings is no longer needed, which resulted in 4% efficiency improvement. Hollow rotor structure was adopted to achieve lightweight
Wang, QianzhenYuan, XixinTao, ZhangFeng, Jin ZengWang, JuanXiao, YongZhou, LeiXin, Jun
A new method for bearing preload measurement has shown potential for both high accuracy and fast cycle time using the frequency response characteristics of the power transmission system. One open problem is the design of the production controller, which relies on a detailed sensitivity study of the system frequency response to changes in the bearing and system design parameters. Recently, an analytical model was developed for multi-row tapered roller bearings that includes all appropriate bearing and power transmission system design parameters. During the assembly process, some of the parameters related to the roller positions cannot be controlled. These parameters include the actual position of the first roller compared to the vertical axis, the relative position of the rollers between the bearing rows, and others. This work presents a sensitivity analysis of the effects of those uncontrollable parameters on the analytical model. The sensitivity study determines the percentage change
Gruzwalski, DavidMynderse, James
Many countries around the world are currently working toward carbon neutrality, which would reduce greenhouse gas emissions to net zero by 2050. To achieve carbon neutrality, the search for new fuels to replace gasoline has been active. This study focuses on hydrogen and methanol fuels and examines their effects on plain bearings when these fuels are used in internal combustion engines. Compared to gasoline, these fuels differ significantly in the composition of gases produced after combustion. It is assumed that nitric acid, etc. will be mixed in the engine oil when hydrogen is combusted whilst formic acid, etc. will be mixed in the engine oil when methanol fuel is combusted. For this reason, corrosion tests were conducted by adding nitric acid or formic acid solution to the engine oil then placing plain bearings in the deteriorated oil. The results confirmed that significant corrosion of the bismuth overlay coating occurred and subsequently the performance of plain bearings may
Kondo, MakotoKawaura, HirokiShiroya, TomoyasuWatanabe, Airi
The increased importance of aerodynamics to help with overall vehicle efficiency necessitates a desire to improve the accuracy of the measuring methods. To help with that goal, this paper will provide a method for correcting belt-whip and wheel ventilation drag on single and 3-belt wind tunnels. This is primarily done through a method of analyzing rolling-road only speed sweeps but also physically implementing a barrier. When understanding the aerodynamic forces applied to a vehicle in a wind tunnel, the goal is to isolate only those forces that it would see in the real-world. This primarily means removing the weight of the vehicle from the vertical force and the rolling resistance of the tires and bearings from the longitudinal force. This is traditionally done by subtracting the no-wind forces from the wind at testing velocity forces. The first issue with the traditional method is that a boundary layer builds up on the belt(s), which can then influence a force onto the vehicle’s
Borton, Zackery
The drive unit of electric vehicles is a complex system consisting of an electric motor and a gear train, which work together to provide the necessary power for vehicle propulsion. One essential component within this system is the ball bearing, which supports the rotating components such as gears and shafts. This study focuses on the thermal simulation of a ball bearing within the drive unit conducted using the Volume of Fluid (VOF) method coupled with mixed timescale Conjugate Heat Transfer (CHT) in Simerics-MP+ to reduce the computational time while ensuring accuracy in the analysis. The Computational Fluid Dynamics (CFD) approach considers the geometrical details and clearances of the inner race, outer race, cage, and ball within the ball bearing. By accounting for the relative motions between these components, it can accurately model the film formation of the lubricating oil and its impact on heat removal from the bearing. The simulations are conducted at two different shaft speeds
Ballani, AbhishekMotin, AbdulDhar, SujanGanamet, AlainMaiti, DipakRanganathan, RajPandey, Ashutosh
This specification covers the requirements for a refined paraffinic petroleum-base lubricant.
AMS B Finishes Processes and Fluids Committee
This specification covers a premium aircraft-quality, corrosion-resistant steel in the form of bars, wire, forgings, mechanical tubing, and forging stock.
AMS F Corrosion and Heat Resistant Alloys Committee
This study proposed the different micro-textures of the SC (square cylinder), SWS (square wedge shape), HS (hemispherical shape), and CR (cylindrical round) to improve the working efficiency of the journal bearing. A hydrodynamic lubrication model of the journal bearing under the impact of the changing dynamic loads is established to analyze the performance of micro-textures. The maximum oil film pressure and minimum frictional force in the journal bearing are selected as two evaluation indices. Some outstanding research results show that all the SC, SWS, HS, and CR added on the bearing surface improved the working efficiency of the journal bearing better than without the micro-textures. Moreover, the HS also improved the working efficiency of the journal bearing better than other structures of SC, SWS, and CR. To optimize the working efficiency of the journal bearing using HS, the dimension ltex and depth htex of HS should be selected and designed in a range of 3.6 < ltex ≤ 3.9 mm and
Song, FengxiangNguyen, VanliemLiu, Yaxi
The stiffness and positioning of engine mounts are crucial in determining the powertrain rigid body modes and kinetic energy distribution. Therefore, optimizing these mounts is essential in the automotive industry to separate the torque roll axis (TRA) and minimize vibration. This study aims to enhance mount locations by isolating the engine rigid body modes and predicting the inter-component force (ICF) and transfer function of the vehicle. The individual ICFs for engine mountings are calculated by applying a unit force at the bearing location. Critical frequencies are identified where the amplification exceeds the unit force at the mounting interface between the engine and the frame. The transfer function approach is utilized to assess the vibration at the handlebar. Both ICF and transfer functions analyze the source and path characteristics linked to critical response frequencies. This understanding aids in enhancing mounting positions to minimize vibration levels, thereby enhancing
Jha, Niraj KumarYeezaku, Antony NeominVictor, Priyanka EstherKrishnamurthy, Govindasamy
In manual transmission, bearing preload is a vital factor for optimum durability and performance of tapered roller bearings (TRB). To achieve better optimization of bearing preload, a precise measurement method is a minimum requisite. This technical paper investigates multiple ideas and develops a novel methodology for accurate bearing preload measurement, overcoming the challenges produced by the complexity of transmission design. This paper provides a systematic approach to bearing preload measurement in manual transmission along with identification of key parameters responsible for influencing bearing preload, such as rigidity and fit of the components. A comprehensive experimental study at both part level and system level was conducted to quantify the effects of above-mentioned parameters on preload and transmission performance. Furthermore, the paper explores the effect of bearing preload optimization on the durability performance of the transmission unit.
Gaurav, KumarKumar, ArunSingh, Maninder PalDhawan, SoumilSingh, KulbirKumar, KrishanSingh, Manvir
This standard covers the requirements for non-separable, airframe antifriction needle bearings and corrosion-resistant and traditional materials intended for use in flight vehicle control systems with radial loads.
ACBG Rolling Element Bearing Committee
This standard covers the requirements for spherical, self-aligning, self-lubricating bearings that are for use in the ambient temperature range of -65 to +160 °F (-54 to +71 °C) at high cyclic speeds. The scope of the standard is to provide a liner system qualification procedure for helicopter sliding bearings defined and controlled by source control drawings. Once a liner system is qualified, the source controlled bearings may be further tested under application conditions.
ACBG Plain Bearing Committee
This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.
AMS E Carbon and Low Alloy Steels Committee
This specification covers a corrosion- and heat-resistant steel in the form of bars, wire, mechanical tubing, forgings, and forging stock.
AMS F Corrosion and Heat Resistant Alloys Committee
Recurring thermal loads in a vehicle can lead to the failure of rubber bearings due to thermal aging within the expected vehicle lifetime. The disadvantages of a preventive or reactive maintenance strategy are high warranty costs and low customer satisfaction, respectively. This work proposes a predictive maintenance system, which monitors the thermal aging of rubber bearings and indicates their timely replacement. Since no real temperature sensors are installed at rubber bearings in production vehicles, virtual temperature sensors are used to monitor component temperatures during customer operation. As a virtual sensor, a feedforward neural network is trained on measurement data in order to learn to predict the component temperatures of several rubber bearings in a combustion engine vehicle based on existing vehicle signals. The neural network achieves an average mean absolute error of 1.78 K and a coefficient of determination of 0.95 over all components after hyperparameter tuning
Freytag, LukasRottengruber, HermannEnke, Wolfram
Rolling bearings play a critical role in rotating machinery, with their fatigue life directly impacting equipment’s operational reliability. This underscores the significant engineering application value of “fault diagnosis” (FD) technology for rolling bearings in mechanical, automation, and aerospace domains. Literature reviews highlight that a substantial portion of failures in machinery such as jet turbine engines, wind turbines, gear reducers, and induction machines are attributable to bearing issues. Early fault detection and preventive maintenance are therefore imperative for ensuring the smooth operation of rotating machinery. This paper focuses on rolling bearings, delving deep into FD technology using machine learning principles. It analyses the structure and common failure modes of rolling bearings, discussing an FD method based on machine learning. Specifically, the SE-DRN (“squeeze-exclusion deep residual network”) approach is employed, leveraging “variational modal
Muin, Abdullah-AlKhan, ShahrukhMiah, Md Helal
A bearing is a mechanical component that transmits rotation and supports load. Depending on the type of rotating mechanism, bearings are categorized into ball bearings and tapered-roller bearings. Tapered-roller bearings are superior to ball bearings in load-bearing capabilities. They are used in applications where high loads, such as, the wheel bearings for commercial vehicles and trucks, aircraft, high-speed trains, and heavy-duty spindles for heavy machinery must be supported. The demand for reducing the friction torque in automobiles has recently increased owing to carbon-emission regulations and fuel-efficiency requirements. Therefore, research on the friction torque of bearings is essential; studies have been conducted on lubrication, friction, and contact in tapered-roller bearings. There have also been studies on lip friction, roller misalignment, and so on; however, research on the influence of roller geometries and material properties is scarce. This study investigated the
Lee, SeungpyoAn, Hyun Gyu
Metal matrix composites (MMCs) have evoked a keen interest in recent times for their potential applications in automotive and aerospace industry components. One such particulars include dry sliding bearings, which have widespread applications in various industries due to their self-lubricating properties, high wear resistance, and low maintenance requirements. The wear as a consequence of metal-to-metal friction can have a detrimental effect, expediting malfunctions or much more adverse spin-offs on the whole system. This study focuses on the development and characterization of a novel dry bearing material composed of a MMC consisting of aluminum (Al), titanium dioxide (TiO2), and silicon carbide (SiC). Tribological tests revealed a low friction coefficient, ensuring efficient and reliable operation. The results indicate the enhancement of MMC’s performance and durability in dry bearings, contributing to the efficiency and reliability of engineering systems. The study not only
Ravi Raj, V.Dhivya Praban, S. V.Jayasooriya, M.Sairam, T. S.
This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.
AMS E Carbon and Low Alloy Steels Committee
This document defines the criteria used for the selection and placement of landing gear shock strut upper and lower bearings (see Figure 1). Common problems associated with shock strut bearings are presented herein.
A-5B Gears, Struts and Couplings Committee
Electric vehicles offer cleaner transportation with lower emissions, thus their increased popularity. Although, electric powertrains contribute to quieter vehicles, the shift from internal combustion engines to electric powertrains presents new Noise, Vibration, and Harshness challenges. Unlike traditional engines, electric powertrains produce distinctive tonal noise, notably from motor whistles and gear whine. These tonal components have frequency content, sometimes above 10 kHz. Furthermore, the housing of the powertrain is the interface between the excitation from the driveline via the bearings and the radiated noise (NVH). Acoustic features of the radiated noise can be predicted by utilising the transmitted forces from the bearings. Due to tonal components at higher frequencies and dense modal content, full flexible multibody dynamics simulations are computationally expensive. Based on previously developed metrics for sound quality, a methodology is proposed with the requirements
Ricardo Souza, MarcosOffner, GuenterMohammadpour, MahdiAndreou, PanagiotisTheodossiades, Stephanos
The commitment to environmentally friendly transportation calls for efficient solutions with the evolution of automotive industry. Turbochargers are an important part of this development. The application of Gas or Air Foil Bearings (GFB) instead of traditional hydrodynamic bearings is recently very noticed, with which the fuel consumption, and emissions can be minimized as well as decreasing the maintenance costs and increasing the reliability. However, low viscosity of gas leads to lower dynamic stiffness and damping characteristics resulting in low load carrying capacity and instability at higher speeds. Gas bearings can be enhanced by adding a foil structure commonly known as gas foil bearings whose dynamic stiffness can be tailored by modifying the geometry and the material properties resulting in better stability and higher load carrying capacity. A detailed study is required to assess the performance of high-speed rotor systems supported on GFBs, therefore in this study a bump
Mandapalli, Prithvi RajuHoefler, DieterRohani, Rezvan
In the contemporary industrial landscape, machinery stands as the cornerstone of various sectors. Over time, these machines undergo wear and tear due to extensive use, leading to the introduction of subtle faults into the machine readings. Recognizing the pivotal role of machinery in diverse industries, the timely detection of these faults becomes imperative. Early fault detection is crucial for preventing costly downtimes, ensuring operational efficiency, and enhancing overall safety. This paper addresses the need for an effective condition monitoring and fault detection system, focusing specifically on the application of the Long Short-Term Memory (LSTM) deep learning model for fault detection in bearings using accelerometer data. The preprocessing phase involves extracting time domain features, encompassing normal, differentiated, integrated, and carefully selected signals, to create an informative dataset tailored for the LSTM model. This model is then meticulously trained on the
Vaishnavi, A.Sharma, AnjuNaidu, VPS
The purpose of this document is to provide detailed requirements to preclude the acquisition and use of suspect counterfeit or counterfeit bearings and/or bearing components/materiel. The term bearings referenced throughout this document includes bearings and/or bearing components/materiel (e.g., balls, races, lubricant, cage, seal). The requirements of this document supplement the requirements of a higher-level quality standard (e.g., AS/EN/JISQ9100, ISO 9001, ANSI/ASQ E4, ASME NQA-1, AS9120, AS9003, and IATF 16949 or equivalent) and other quality management system documents. All appendices are provided for guidance and are not mandatory.
G-21 Counterfeit Materiel Committee
This specification covers a corrosion-resistant steel in the form of bars, wire, forgings, and forging stock.
AMS F Corrosion and Heat Resistant Alloys Committee
Churning loss is an important energy loss term for rolling bearings at high-speed condition. However, it is quite challenging to accurately calculate the churning loss. A CFD study based on unsteady Reynolds-Averaged-Navier-Stokes that resolves the gas-liquid interface was performed to examine the unsteady multiphase flow in a roller/ball bearing. In this study, the rotating motion of the cage, races, rollers/balls about the shaft as well as self-rotation of rollers/balls about their own axis were accounted to accurately predict the oil distribution in various parts of the bearings. A novel meshing strategy is presented to resolve thin gaps between the roller/balls and the races/cage while preserving the shape of balls/rollers, races and cage. Five rotational speeds of the shaft have been examined for roller bearing and ball bearing respectively. Additionally, effect of clearance between roller/balls and races is investigated. Of particular interest is to examine the mechanisms
Pandey, AshutoshTao, MingyuanLiu, YuchuanWu, RanShandilya, AnandWang, Chengjie
Optimized half-shaft design is paramount to deliver power from a drive unit and gearbox to the wheels of a vehicle. An intermediate shaft must be able to deliver rotational force to the wheel with acceptable efficiency to prevent any sort of torque losses or torque steer when coupled with another shaft. Intermediate shafts must be optimized for torque delivery, stiffness, weight, and efficiency relative to the CV shaft it is coupled to. For the unique switched reluctance motor that is utilized in this study, the shaft will be supported by a fixed housing in which a bearing will be affixed. It is critical that through these studies an attempt is made to optimize all these conditions by selecting the best materials as well as study the effects of having a tubular shaft as opposed to one that is solid using computer software. This analysis was completed with specific constraints in mind with respect to both shaft performance as well as packaging constraints. Processes include design for
Fares, George Maher AlfiGleeson, AdamRajotte, LucasEmadi, Ali
In order to study the tire friction characteristics under wet skid surface, the “pseudo” hydrodynamic pressure bearing effect is used to be equivalent to the hydrodynamics of water film, and an advanced Lugre tire hydroplaning dynamic model is developed by combining the arbitrary pressure distribution function. The water hydroplaning dynamic tests were carried out for 285/70R19.5 tire under wet of different water film thickness and dry conditions, and the parameters of the advanced Lugre tire dynamic model were identified. The results show that the tire water-skiing model proposed in this paper can effectively simulate the friction characteristics of tires under different water film thicknesses. Under dry conditions, 0.5mm water film and 1mm water film road conditions, the relative errors of the maximum tire friction coefficient between the tested and advanced Lugre tire model are 1.11%, 0.12% and 0.16%, respectively. The root mean square (RMS) relative errors of tire friction
Zhu, HengjiaQi, KaiWang, LliwenZhang, Wei
The process of assembling the bearing and crimp ring to the steering pinion shaft is intricate. The bearing is pressed into its position via the crimp ring, which is tipped inward and fully fitted into a groove on the pinion shaft. Only when the bearing is pressed to a low surface on the pinion shaft, the caulking force for the crimp ring is achieved. The final caulking distance for the crimp ring confirms the proper bearing position. Simulating this transient fitting process using CAE is a challenging topic. Key factors include controlling applied force, defining contact between bearing and pinion surface, and defining contact between crimp ring and bearing surface from full close to half open transition. The overall CAE process is validated through correlation with testing.
Song, GavinVlademar, MichaelVenugopal, Narayana
Recently, there has been a new method for setting bearing preload on tapered roller bearings in a power transmission system. To move this new method into production, an analytical model that relates the bearing preload to the stiffness of the bearing was developed. This work develops an analytical model that links the preload on multi-row tapered roller bearings to the stiffness of the power transmission system. This study also validates the proposed analytical model by comparing it to both previous work and commercially available simulation software. The analytical model has shown that it is highly sensitive to the number of rollers in the bearing, which is discussed in this work.
Gruzwalski, DavidMynderse, James
One often reported roadblock to consumer acceptance of electric vehicles is driving range, which is a function of powertrain efficiency and vehicle mass. Electric vehicle gearbox design often is based on multiple parallel shafts, thereby creating significant packaging constraints. Industry perception holds that deep groove ball bearings (DGBB) are more efficient than tapered roller bearings (TRB), and standard spin-loss testing confirms those beliefs. However, spin-loss efficiency testing does not accurately reproduce typical real-world driving. A more realistic comparison of bearing efficiency is required to properly select bearings during the powertrain design stage. Recently completed testing focused on recreating application conditions (including bearing loads, speeds, misalignment, and load zones) for electric vehicle gearbox intermediate shafts. These conditions varied between TRB and DGBB as a result of application bearing setting and reaction load changes and were faithfully
Feltman, John W.
Nowadays, Bismuth (Bi) is being applied as an overlay material for engine bearings instead of Lead (Pb) which is an environmentally harmful material. Bi overlay has already been a solid performer in some automotive engine sectors due to its superior load carrying capacity and good robustness characteristic which are necessary to maintain its longevity during the lifetime of engines. The replacement is also seen on relatively larger size engines, such as Trucks and Off-highway heavy duty applications. Basically, these applications require higher power output than passenger cars, and the expected component lifecycle becomes longer. Though Bi has similar material characteristic to traditional Pb, it becomes challenging for the material alone to satisfy these requirements. Polymer overlay is known for its superior anti-wear performance and longer lifetime due to less adhesion against a steel counterpart than metallic materials (included Bi). However, for heavy duty applications where clean
Haneda, YumaKato, KentaYasuda, ErinaNogami, AkiraHayashi, Masaki
Heavy vehicles such as construction machinery generally require a large traction force. For this reason, axle components are equipped with a final reduction gear to provide a structure that can generate a large traction force. Basic analysis of vertical load, horizontal load (traction force), centrifugal force, and torsional torque applied to the wheels of heavy vehicles such as construction machinery and industrial vehicles, as well as actual working load analysis during actual operations, were conducted and compiled into a load analysis diagram. The loosening tendency of wheel bolts and nuts that fasten the wheel under actual working load was measured, and the loosening analysis method was presented. The causes of wheel fall-off accidents in heavy trucks, which have recently become a problem, were examined. Wheel bolts are generally tightened by the calibrated wrench method using a torque wrench. The method is susceptible to variations in friction coefficient and tightening torque
Hareyama, SoichiManabe, Ken-ichiKobayashi, Satoshi
Effective design of the lubrication path greatly influences the durability of any transmission system. However, it is experimentally impossible to estimate the internal distribution of the automotive transmission fluid (ATF) to different parts of the transmission system due to its structural complexities. Hybrid vehicle transmission systems usually consist of different types of bearings (ball bearings, thrust bearings, roller bearings, etc.) in conjunction with gear systems. It is a perennial challenge to computationally simulate such complicated rotating systems. Hence, one-dimensional models have been the state of the art for designing these intricate transmission systems. Though quantifiable, the 1D models still rely heavily on some testing data. Furthermore, HEVs (hybrid electric vehicles) desire a more efficient lubrication system compared to their counterparts (Internal combustion engine vehicles) to extend the range of operation on a single charge. Thus, this paper includes a
Mohapatra, Chinmoy K.Schlautman, JeffLiu, ZheRaj, GowthamGao, Haiyang
As part of the development of its new powertrain consisting of two electric motors, a combustion engine and a gearbox, Renault SAS followed an original approach to achieve an assembly with an optimized, robust, and reliable link between the main electric motor and the gearbox. The running operation optimization as well as the high reliability is achieved by processing the following topics: filtration of vibrations and operating jolts; solving of tribological problems specific to splined connections, such as fretting corrosion and abrasive tooth wear; avoidance of potential seizure of elements with cyclic relative slippage under load; and eventually, control of wear and tear on the sealing and damping O-rings, which must accept oscillating translational movements at the same time as torque transfer. The aim of this article is to retrace the main steps taken to achieve the desired reliability and performance targets for this type of product. The most remarkable points of this approach
Hay, MaximeDutfoy, LaurentLigier, Jean-louisMerçay, Patrice
The study focuses on understanding the air and oil flow characteristics within a ball bearing during high-speed rotation, with a particular emphasis on optimizing frictional heat dissipation and oil lubrication methods. Computational fluid dynamics (CFD) techniques are employed to analyze the intricate three-dimensional airflow and oil flow patterns induced by the motion of rotating and orbiting balls within the bearing. A significant challenge in conducting three-dimensional CFD studies lies in effectively resolving the extremely thin gaps existing between the balls, races, and cages within the bearing assembly. In this research, we adopt the ball-bearing structured meshing strategy offered by Simerics-MP+ to meticulously address these micron-level clearances, while also accommodating the rolling and rotation of individual balls. Furthermore, we investigate the impact of different designs of the lubrication ports to channel oil to other locations compared to the ball bearings. This
Mohapatra, Chinmoy K.Schlautman, JeffPandey, AshutoshWang, ChengjieSrinivasan, Chiranth
Threaded joints are considered the most basic of components. Although in use for over a century, significant problems still exist with their usage. Wheel bolt loosening in overloaded segments such as HD tippers and high-speed intercity buses poses a safety challenge for drivers, passengers, and pedestrians. Wheel nut loosening is a notable cause of service, fretting, and cracks in the mating components; contributing a significant chunk of warranty cost to the company. The need of the hour is to reinforce these joints while keeping resources at bay. This paper establishes a methodology for the evaluation and design of a safe wheel bolt joint interface including key parameters such as embedding, axial forces, and shear forces. It is necessary to obtain the minimum preload requirement for a wheel bolt joint to hold the clamped surfaces intact, which if not maintained otherwise would cause relative movement, play, shear load onto the bolt, and eventually failure. For physically auditing
Raghatate, ShreyasSharma, SuchitSindal, Vinayak
With the use of the stepped surface of the friction pairs of the stepped bearings (SB) in the high-speed centrifugal pumps, its liquid film thickness is suddenly changed and it was discontinuously distributed in the direction of motion of pump. To ensure the continuity of the liquid film thickness and enhance the lubrication efficiency of the pump, based on the lubrication model of the SB, two other structures of the inclined surfaces [inclined bearings (IB)] and curved surfaces [curved bearings (CB)] used to replace stepped surfaces of the SB are investigated, respectively. Under the same conditions of the minimum thickness of the liquid film and initial dimensions of the sliding friction pairs, the influence of both the thickness ratio (α) of the liquid film and dimension ratio (β) in the direction of motion of SB, IB, and CB on the bearing capacity and friction coefficient of the liquid film are simulated and analyzed, respectively. Based on the optimal ratios {α and β} of SB, IB
Chen, HanxinGuo, XiaoyanNguyen, Vanliem
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