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The force and torque transmitted by the ball cage constant velocity universal joint transmission assembly of heavy⁃duty vehicles are greater than that of ordinary vehicles,and the working conditions have higher requirements.Under the impact load,static strength failure or fatigue failure of the intermediate shaft may occur,as well as the cage damage under the bigger interaxial angles.Therefore,it is very important to study the strength of the intermediate shaft and the cage in the ultimate working condition.In this study,the ball cage constant velocity universal joint transmission assembly for a heavy⁃duty vehicle was taken as the object.Firstly,the force analysis and the finite element simulation were carried out on the intermediate shaft and the results were compared to verify the model accuracy.Secondly,the stress distribution and variation law of the cage were obtained through simulation analysis under the different interaxial angles.Finally,the torsional static strength test and the cage hardness test were carried out.The results show that the intermediate shaft and the cage meet the requirements under normal working conditions,but the cage may be broken under extreme working conditions.This research can provide reference for the design and manufacture of ball cage constant velocity universal joint transmission assembly of heavy⁃duty vehicles.

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Modular robots can adapt to different production needs and working conditions. However, the complexity of structures and the choice of driving modes limit the development of modularization. In this paper, a robot joint module with a universal joint configuration driven by shape memory alloy (SMA) wires is proposed, which has 2-DOFs. For lightweight, the main body of the module is made of polylactic acid materials. SMA wires are used as the actuator due to the advantages of large output displacement, high mass-to-energy ratio, and low activation voltage. Adopting antagonistically arranged SMA wires and bias springs combination method increases the recovery speed and driving angles. A locking device is creatively proposed to avoid the influence of self-biasing spring compression. The detailed kinematic model of the module is established. A proportional integral differential controller is used to precisely control module movements, and the attitude angle sensor is used as the monitoring device. Through the maximum rotation angles and trajectory tracking movement experiments, the module is tested comprehensively, and the results show that the module has good movement characteristics and control precision. In addition, analyzing the tracking performance of the module in the time domain shows that the module has a relatively fast tracking speed. This module is beneficial to the research of configurations, actuators, and controls of modular robots. [ABSTRACT FROM AUTHOR]

Utilizing a universal joint can lead to significant vibration within a driveline system. This study presents a model for analyzing the torsional and lateral vibrations of a driveline connected by a double universal joint. The governing equations of motion are derived, and the Runge-Kutta method computes steady-state responses across a spectrum of input rotational speeds. The focus is to examine the effect of system parameters, including static angular misalignment, load torque, and lateral stiffness. Relative amplification is used to analyze the effects of parameters on system vibration. Results indicated that the second-order component of input rotational speed induced by the universal joint was the factor that caused the vibrations. For the considered system, static angular misalignment significantly impacts both the torsional and lateral vibrations. Increasing the angular misalignment from 15° to 30° results in a threefold increase in lateral vibration amplification, while torsional vibration amplification is increased by nearly two times. The effect of load torque is almost linearly proportional to torsional vibration but is nonlinear to lateral vibration. Thus, lateral vibration is significantly impacted compared to torsional vibration for higher load torque. Changing the stiffness leads to a modification of the natural frequency. Increasing the lateral stiffness shifts the critical speed to a higher speed range, resulting in reduced lateral vibration amplitude. It is demonstrated that a slight fluctuation in angular misalignment due to lateral vibration will not affect the torsional vibration even if both vibrations are coupled. The findings may enhance understanding of how changing system parameters affects vibration. [ABSTRACT FROM AUTHOR]

Compliant joints have significant advantages compared to rigid-body hinges due to a monolithic design and the absence of friction, which prevents effects like wear, backlash, and stick-slip behavior. However, the loading capability is often limited and the support stiffness generally decreases during rotation. A new design principle called closed form pressure balancing has been proposed as a solution to improve these limitations. By using an incompressible fluid as the main compliant element, the support stiffness becomes independent of rotation and buckling no longer limits the loading capability. This work analyzes the fundamental working principle behind closed form pressure balancing and introduces a 2D design model to determine stiffness properties. The design model is validated with a finite element model and used to construct an optimization strategy for optimum joint performance. Additionally, a conversion model and some practical considerations are presented for the transition to a 3D design model. [ABSTRACT FROM AUTHOR]

The paper analyzes the problems of the most commonly used cardan shafts in agricultural machinery through a theoretical review and tests on a laboratory test bench. The aim of the research presented in this paper was to define the justification of a new method for retrofitting universal joint bearing units compared to the traditional methods of retrofitting. The new approach is based on energy efficiency (saving energy, raw materials and labor) compared to the conventional methods of retrofitting. The presented investigation to justify the proposed refit was carried out after the investigation of the extent of damage to the elements of the bearing assembly, which lasted 4.02 minutes per sample, with the aim of obtaining information essential for the purpose of our work. The proposed diagnosis and refit of the cardan bearings can help to extend the service life and improve the reliability of the universal joint shafts already in service. The results of the research have shown that the method with replaceable bushings (installation of undamaged surfaces in the load transfer zone) is 6.24 to 7.54 times cheaper than the complete repair of the elements of the bearing assembly, 2.11 to 2.83 times cheaper than the refit method, in which the damaged joints are replaced with new ones, and 1.62 to 2.74 times cheaper than the purchase of new double PTO (Power Take-Off) shafts.

The study examined the strength of the universal joint after it was loaded with torsion. It used different materials that can withstand tensile stress in accordance with accepted principles and made modifications to the yoke as a result of the topology optimization process. The topology optimization determined that the yoke's part needed to withstand load without changing its dimensions and minimize stress distribution. According to the results, the maximum shear stress on the spider of the original universal joint model made of JIS-SF590A steel was 84.57 MPa, the shear stress on the yoke component was 30.84 MPa, and the maximum von Mises was 341.1 MPa. As a result of using JIS-SF590A steel, yoke modification 3 has produced a reduction in shear stress of 12.97 % and a reduction in von Mises stress of 35.33 % from the original yoke. This is the most efficient design of yoke and also this modified yoke form provides a wider elevation angle and is easier to manufacture.

In submarine oil and gas pipelines, the movement of a differential pressure multisection pipeline robot mainly relies on the front and rear driving pressure difference of the fluid and the friction between the cup and the pipe wall. The passability of the pipeline is a key point to guarantee success in scanning and detecting the inner wall of a pipeline by robot. When the multisection pipeline robot moves, the force of the internode connection points changes the degree of freedom of the robot. The existence of the connection points causes speed fluctuations in the robot during the movement process which, in turn, affects the detection accuracy of the pipeline. Consequently, a systematic analysis of the connection point movement is of great importance. In this paper, a rigid–flexible, coupled, multibody, dynamic motion system is established, where a multisection micro pipeline robot is built. The cup of the robot is set as a flexible body. The motion law of the differential pressure multisection pipeline robot is analyzed through simulation, and the robot's motion speed and internode stress of the different cabin sections are explored jointly in practice. Taking the transportation of an oil and gas pipeline into full consideration, the motion law and force of the multisection pipeline robot are analyzed by changing the bulge and turning the radius of the inner wall of the pipeline. A corresponding experimental bench is built to explore the effects of different numbers of cups and lengths of the cabin sections on the turning characteristics of the robot. Simulations and experiments results are highly similar and within the error range. To this end, the presented work provides significant information for the model selection of multisection micro pipeline robots in the fields of submarine oil and gas pipelines. [ABSTRACT FROM AUTHOR]

The structure of a steering system plays an important role in the vehicle's handling performance. Considering the convenience of changing the structural parameters of the steering system, the phase angle of universal joints and the initial angle of steering shaft are selected as the structural parameters to be studied in this paper. The kinematics of the steering system and the dynamics of the whole vehicle are analyzed theoretically. The simulation study shows that the phase angle mainly influences the fluctuation of the steering ratio, the initial angle mainly influences the symmetry of the steering ratio. The transient and steady-state objective evaluation indexes vary with the phase angle and the initial angle at a period of 180°. Through optimization research, it is demonstrated that the handling performance of a vehicle can be improved in the direction of the desired level by matching the initial angle and phase angle. [ABSTRACT FROM AUTHOR]

This paper introduces an original, fully compliant universal joint design. Many mechanisms with different dimensions are investigated. The proposed design is a single-piece compliant mechanism. The number of flexible segments is a design parameter determined as a function of transferred torque. The mechanism can be produced by additive manufacturing from polylactic acid and polypropylene. It is possible to produce the proposed design as a single piece of polypropylene by additive manufacturing and injection molding methods; thus, it has the advantage of ease in manufacturing. The proposed design's bending and torque transmission capacities are determined by applying analytical and numerical methods. Furthermore, a prototype was manufactured, and experiments were conducted. It is verified that the results of the experiments are consistent with theoretical approaches. The proposed fully compliant universal joint design has a great potential in the industry. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The load of ball cage type constant velocity joint of military off-road vehicle is larger than that of traditional vehicle, and the working condition is bad, which may cause contact wear, as well as the fracture of the cage under the angle between large axes. Therefore, it is very important to study the contact stress and the strength of the cage under the bad working condition. In this paper, a typical military off-road vehicle ball cage constant velocity joint is taken as the object. Firstly, the contact stress between the steel ball and the inside and outside raceway is theoretically analyzed and simulated. The simulation and analytical results are compared to verify the correctness of the simulation model. Secondly, according to the load transfer relationship between the key parts of the universal joint and the physical experiment, the reason and process of cage fracture are analyzed. Finally, the static torsion test under the ultimate axial angle is carried out, and the hardness test is carried out on the section of the cage. The strength distribution along the thickness is obtained through the relationship between hardness and strength conversion. The results show that the strength of the cage meets the requirements under normal working conditions, but may be broken under bad working conditions. This research can provide theoretical reference for the design and manufacture of constant velocity joint for off-road vehicle.

Dynamic loads of the connecting bolts in a universal joint can greatly affect the bolt fatigue and fracture, as well as the machinery safety and stability. But few researches focused on those. To obtain the dynamic load characteristics of the connecting bolts in a universal joint, this paper established a flexible dynamic model for the connecting bolts. A multibody dynamic model of a universal joint is developed. The dynamic loads on the connecting bolts of the universal joint are analyzed. The influences of the preloads, speeds and loads are studied. The amplitude and frequency properities are obtained. The effect of the preload is small when the preload is in the range of 80%~120% of the standard value. The load and speed have great influence on the time- and frequency-domain dynamic loads of the bolts. The flexible dynamic model of the connecting bolt is closer to the actual situation than the rigid model since it can consider the preload and deformation of the bolts. This study can provide guidance for the fatigue life prediction of the universal shaft and its bolts. [ABSTRACT FROM AUTHOR]

In submarine oil and gas pipelines, the movement of a differential pressure multisection pipeline robot mainly relies on the front and rear driving pressure difference of the fluid and the friction between the cup and the pipe wall. The passability of the pipeline is a key point to guarantee success in scanning and detecting the inner wall of a pipeline by robot. When the multisection pipeline robot moves, the force of the internode connection points changes the degree of freedom of the robot. The existence of the connection points causes speed fluctuations in the robot during the movement process which, in turn, affects the detection accuracy of the pipeline. Consequently, a systematic analysis of the connection point movement is of great importance. In this paper, a rigid–flexible, coupled, multibody, dynamic motion system is established, where a multisection micro pipeline robot is built. The cup of the robot is set as a flexible body. The motion law of the differential pressure multisection pipeline robot is analyzed through simulation, and the robot’s motion speed and internode stress of the different cabin sections are explored jointly in practice. Taking the transportation of an oil and gas pipeline into full consideration, the motion law and force of the multisection pipeline robot are analyzed by changing the bulge and turning the radius of the inner wall of the pipeline. A corresponding experimental bench is built to explore the effects of different numbers of cups and lengths of the cabin sections on the turning characteristics of the robot. Simulations and experiments results are highly similar and within the error range. To this end, the presented work provides significant information for the model selection of multisection micro pipeline robots in the fields of submarine oil and gas pipelines.

Driveshafts are power transmission elements that transmit the torque received from the engine or gearboxes to the differential or another element. When considered vehicle movement and different road conditions, transmission of torque is provided by the ability of length compensation and angular movement of the driveshaft. Angular movement is provided by the driveshaft joint group. The cross-body in a joint group, connects opposing yoke parts to each other, which is considered for selection of suitable driveshaft for a vehicle. Because it is exposed to higher stresses compared to other driveshaft parts during running. Thus, the crossbody should be resistant to the load and the stresses occurred. In the study, stress values on the critical section of the cross-body under different torque values were determined by using analytical and finite element analysis (FEA) methods, and the values obtained by both methods were compared to each other. As a result of the comparison, it was observed that the stress values obtained by both methods were highly close to each other within a difference between 2% and 3%. Finite element analysis requires longer application time compared to the analytical method. Considering that the stress values obtained by both methods overlap with each other, it has been determined that the analytical method can be used at the beginning of the cross-body design of the driveshaft due to its short application time. [ABSTRACT FROM AUTHOR]

A heterogeneous double driving universal joint (HDD-UJ) is proposed, which can realize the pitching motion and the rolling motion. The HDD-UJ uses a universal joint as the prototype of the mechanism, with the motor as the main drive source and the electrostrictive material as the auxiliary drive source. Through the design of the HDD-UJ virtual prototype model, the integrated characteristics of the transmission integration are determined, and the transmission integration mechanism of the joint is described. The spatial motion coordinate system of the HDD-UJ is established, and its kinematics analysis is carried out and the kinematics equation is derived. Based on the mathematical principle of space geometry, the spatial motion range of the HDD-UJ is obtained, and the virtual simulation experiment of motion workspace is carried out. The simulation results show that the HDD-UJ structure is novel and simple, with high integration, and has two degrees of freedom. It can realize a wide range of space operations, and theoretical basis for the study of structural optimization and motion precision control strategies of subsequent joints is provided.

As an important component in the automobile drive system，the performance of drive shaft has influence on NVH performance of the whole vehicle. In order to improve the influence of drive shaft on NVH performance，a design scheme to replace the intermediate universal joint of the drive shaft with Birfield CV joint is proposed based on the transmission characteristics analysis of universal joint and Birfield CV joint. The exciting forces at the inter-mediate support of three universal joint for two kinds of the drive shaft are solved and analyzed respectively. Results show that， due to the stable additional bending moment，the Birfield CV joint can reduce the exciting force at the intermediate support as well as the body of the vehicle，thus the NVH performance of the whole vehicle is improved.

The controllable universal joint flexible slender structure in the tubes was an unique structure of the ultra-short radius horizontal wells. Considering the mechanism problems of controllable universal joint structures where the three-body two-layer contact problems of structural discontinuity and slotted incomplete structure, the 3-D beam elements, universal joint elements, rigid beam elements and the bean-beam contact elements were combined. A two-layer contact nonlinear fiinte element model of a controllable universal joint flexible structure in the tubes was established and a numerical calculation method was carried out. It was compared with an analytical solution by an exam-ple. The calculation results are in good agreement. The Mechanics analyses of the flexible drilling tools in oblique drilling of ultra-short radius horizontal wells was carried out. The deformation state, the law of load transmission of the flexible drilling tool and the distribution law of the contact forces with the borehole walls were obtained. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The lack of research on flexible drilling tool leads to limited application of ultra-short radius horizontal wells. The flexible drilling tool is different from the conventional drilling tool. The flexible drilling pipe involves a mutual transition between the structure and the mechanism during the deformation process. At the same time, the flexible drilling pipe and the eccentric guide tube, the guide tube and the wellbore generate random contact. In this paper, 3-D beam elements, universal joint elements, rigid beam elements and the beam-beam contact elements are combined to establish a two-layer contact nonlinear finite element model of the flexible drilling tool in the wellbore. The dynamic relaxation method is introduced for numerical solution. The feasibility of the model and the algorithm is verified by an example. The mechanical analysis of flexible drilling tool under the four hole inclinations in the oblique section is carried out. It is found that the flexible drilling pipe has a "folded line" deformation. The contact force between the flexible drilling pipe and the guide tube is randomly distributed. The contact force between the guide tube and the wellbore in the oblique section is greater than that in the vertical section. As the hole inclinations increase, the torque and axial force transmitted to the drill bit gradually decrease. [ABSTRACT FROM AUTHOR]

Abstract Background In a macro-molecular complex, any minor change may prove detrimental. For a supra-molecular nano-machine like the bacterial flagellum, which consists of several distinct parts with specific characteristics, stability is important. During the rotation of the bacterial flagellar motor, which is located in the membrane, the flagella rotate at speeds between 200 and 2000 rpm, depending on the bacterial species. The hook substructure of the bacterial flagellum acts as a universal joint connecting the motor to the flagellar filament. We investigated the formation of the bacterial flagellar hook and its overall stability between the FlgE subunits that make up the hook and attempted to understand how this stability differs between bacteria. Results An intrinsically disordered segment plays an important role for overall hook stability and for its structural cohesion during motor rotation. The length of this linker segment depends on the species of bacteria; for Salmonella enterica and Campylobacter jejuni it is approximately 37 and 54 residues, respectively. Few residues of the linker are conserved and mutating the conserved residues of the linker yields non-flagellated cells. In the case of Campylobacter, which rotates its flagella at a speed much higher than that of Salmonella, shortening the linker leads to a rupture of the hook at its base, decreasing cell motility. Our experiments show that this segment is required for polymerization and stability of the hook, demonstrating a surprising role for a disordered region in one of the most finely tuned and closely studied macromolecular machines. Conclusions This study reveals a detailed functional characteristic of an intrinsically disordered segment in the hook protein. This segment evolved to fulfill a specific role in the formation of the hook, and it is at the core of the stability and flexibility of the hook. Its length is important in the case of bacteria with high-speed rotating flagella. Finding a way of disrupting this linker in Campylobacter might help in preventing infections.

In this study, an analysis was conducted to investigate how misaligned cardan shaft could result in failure of gearbox in CRH high speed train. The cardan shaft was used to provide rotating motion from motor to gearbox. The study began with an analysis of the failure of a serviced gearbox in CRH train. It was revealed that rotation of misaligned cardan shaft was the most likely candidate for gearbox fracture which led to total failure of the train. To explain how misaligned cardan shaft led to failure, a kinetic analysis of misaligned cardan shaft was first performed by analytically calculating the force acted on gearbox and followed by an experimental test to validate the results. The results from kinematic analysis indicated a small offset of cardan shaft led to huge inertial force and frictional force acting on the universal joints. These forces resulted in bending load acting on bevel gear shaft and led to vibration. The vibration caused excessive rubbing of the connection and resulted in looseness of the fit. Eventually the gearbox was fractured by violent collision. An experiment was conducted to validate the failure process. The experimental results confirmed the rotational misaligned cardan shaft caused impact between shaft and bearing block. Consequently, this paper proposes a detection method to monitor cardan shaft used in CHR high speed train. For the first time this work conforms it was essential to consider transport acceleration when analyzing unbalance force due to misalignment of cardan shaft. • Systematic studies of kinetics and dynamics of misaligned cardan shaft in rotation. • Design of experimental cardan shaft and test set-up to mimic real life operation. • Investigation on looseness of interference fit of flange leading to gearbox failure. • Confirming the inertial force caused by transport acceleration is the main reason leading to looseness. • Study on influence of misalignment on the friction force of cardan shaft. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Metallographic replication to identify cast and forged states in the field. • Prematurely fractured universal joints produced by the casting process. • Significant structural differences between cast and forged universal joints. • Significant elemental segregation in the interdendritic region. • Forged stainless steel exhibits excellent mechanical properties. This research investigates the failure of stainless steel components in power grid equipment, specifically examining how casting and forging processes affect structural integrity. The focal point is an early fracture of a part initially identified as a universal joint on the B-phase deflection arm. Macroscopic examination, spectral testing, microscopic observation, and Energy Dispersive Spectroscopy (EDS) analysis were used to pinpoint the failure's cause and evaluate casting and forging techniques. Replicas of various manufacturers' fractured and forged stainless steel parts were prepared using portable direct current electrolytic corrosion technology for direct study. The findings showed clear structural variances and elemental segregation patterns, with forged samples demonstrating superior mechanical attributes. These discoveries underscore the importance of appropriate manufacturing processes for ensuring the reliability and performance of stainless steel parts in power grid equipment. They also contribute to improved design and material selection practices in similar contexts. [ABSTRACT FROM AUTHOR]

The effect of universal joint position on the output shaft speed curve phase is analyzed in single universal joint transmission. Then,the fluctuation superposition principle of double universal joint transmission is studied and expanded to multi universal joint transmission. For transmission structure with reduction gears,the delivery of speed at bevel gears and fluctuation superposition of multiple universal joint are analyzed. Finally,by finding the optimum value of the phase angle of each universal joint,the speed fluctuation of the output shaft of a specific vehicle steering mechanism is reduced to a minimum.