最新刊期
期 7 ， 2020
- 摘要：Aiming at the problem of low deadweight ratio of load in joint manipulator，two trajectory planning methods to improve the bearing capacity of the joint manipulator are proposed. The first method gets a new trajectory，this method automatically generates a set of moment smooth motion trajectories by using the correct dynamics model and selecting acceleration values of segmented motion process，the appearance of large peak torque will be avoided by this method. The second method optimizes the existing trajectory，this method first selects a standard predefined motion curve as trajectory. The torque peak of the manipulator is suppressed to lowest by using genetic algorithms to optimize the motion parameters of the curve. The appearance of large peak torque will also be avoided by this method. Through the simulation of Adams，it is found that the joint torque is optimized compared with other commonly used trajectory when lifting heavy objects in these ways. Finally，the correctness and effectiveness of the control method are verified through the experiment.关键词：Joint manipulator
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发布时间：2022-10-20 - 摘要：The traditional research on spalling gear failure mainly focuses on the change of gear stiffness under different spalling depth and width，it has great limitations. Aiming at this problem，the influence of spalling shape and the spalling shape distribution on gear stiffness and dynamics is studied. To begain with，the spalling position is at the place which on the pitch circle of the gear，different spalling shapes are taken at this position. Then，on the basis of the traditional potential energy method，considering the change of spalling width when the meshing position of gears changes，the stiffness curves of different spalling patterns are obtained. Combined with the dynamics changes，the vibration acceleration signals of different faults are analyzed， which shows that the spalling shape factors affect the gear related indicators，making it difficult to distinguish the spalling gear from the normal gear，and the indicators overlap with each other. The method of combined probability density function with kurtosis value is proposed，and the probability density function curve is used to judge the gear fault state. It is found that this method can effectively counteract the interference of shape factor on the index，and has high feasibility and discrimination ability.关键词：Potential energy method
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发布时间：2022-10-20 - 摘要：An algorithm for solving the forward position solution problem of the parallel robot based on Levenberg-Marquardt method is proposed. A kinematics model of a redundantly constrained cable-driven parallel robot is established，and the mechanism is parameterized to solve the inverse position solution problem. The nonlinear equations of forward kinematics are established，and the original pose of the end effector is taken as the iterative initial value to solve the forward position solution problem by applying the proposed algorithm. The Matlab/Simulink/xPC tool is used for simulation experiments. The complex periodic circular curve is selected as the motion trajectory of the parallel robot for the real-time simulation. It is verified that the algorithm can achieve accurate forward position solution and smooth motion trajectory，and has good real-time performance. Five pose combinations are selected to verify the high efficiency of the algorithm. The calculation results show that the algorithm has fewer iterations，shorter computation time and higher accuracy，which provides a theoretical guidance for real-time monitoring and complex control strategies of parallel robots.关键词：Cable-driven parallel robot
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发布时间：2022-10-20 - 摘要：In order to improve the energy consumption economy of a plug-in axle-split hybrid electric vehicle （PHEV），a rule-based energy management strategy is established，and the corrected power factor and speed limits value for engine startup are introduced. The key parameters of the corrected power factor of engine，start-up speed and energy management strategy control rules are optimized offline by using particle swarm optimization （PSO）. On the AMESim-Simulink co-simulaton platform，the optimization model is established and simulated. The results indicate that compared with the non-optimized energy management strategy，the energy consumption economy of the optimized control strategy has been significantly improved，and the overall energy consumption of the vehicle has been reduced by 12.6%.关键词：Plug-in hybrid electric vehicle
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发布时间：2022-10-20 - 摘要：The meshing transmission part of the cycloidal pin wheel is the key structure of the RV reducer，the simulation analysis of virtual prototype based on multi-body dynamics is a common method to study the dynamic characteristics of the RV reducer. Taking into account different loads and different working conditions，the RV reducer is simulated and analyzed based on multi-rigid dynamics. The simulation results visually show the changes of the meshing characteristics of the cycloidal pin teeth under different working conditions. The rigid-flexible coupling technique is used to extract the continuous node stress curve for analysis，and the position and size of the maximum contact force during meshing are determined，and a theoretical basis for the research and improvement on the way of subsequent shaping is provided.关键词：Virtual prototype
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发布时间：2022-10-20 - 摘要：Tilting pad bearings are widely used in modern industry because of their inherent stability，and related research has flourished. However，the study on the tilting pad bearing preload coefficient mainly focuses on the field of low rotational speed. The DyRoBeS software is used as the research tool，and the commonly used five tilting pad bearing is taken as the research object. The influence of the preload coefficient on the working performance of the tilting pad bearing under the high rotational speed conditions of 20 000 r/min，40 000 r/min and 60 000 r/min. The analysis results will provide theoretical basis for the design and application of the tilting pad in high-speed gear transmission. In the process of preload coefficient increased from 0.1 to 0.7，there is no effect on the power loss，but the maximum oil film pressure and stiffness coefficients are increased，the minimum oil film thickness and damping coefficients are decreased. The mixed setting of the preload coefficients affected the pressure distribution of each tilting pad，the bearing performance parameters except the minimum oil film thickness is obviously increased. The conclusion will play a positive role in the optimization design of tilting pad bearing with high rotation rate.关键词：High speed gear transimission
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发布时间：2022-10-20 - 摘要：In view of the existing CNN（Convolution Neural Network） based rolling bearing fault diagnosis method，it is difficult to effectively excavate and utilize the multi-scale information contained in the data，a multi-scale convolution feature fusion method for rolling bearing fault diagnosis is proposed. A convolutional neural network （MSCNN） structure with multi-scale feature extraction and fusion ability is built by adding the upper sampling layer，which improves the understanding ability of the model to the input signal. CWRU database is used to verify the validity of the proposed method. The short-time Fourier transform is used to analyze the spectrum of rolling bearing signals. The spectrum samples are input into MSCNN network. The data analysis shows that the method can effectively improve the fault diagnosis accuracy.关键词：Fault diagnosis;Rolling bearing;Multi-scale convolutional neural network;Short-time Fourier transform
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发布时间：2022-10-20
Theory·Reserach
- 摘要：The conception of the equivalent silent chain plate is proposed，the meshing relations between the inner-outer compound meshing silent chain and involute sprocket are analyzed. The correct form of silent chain plate inner profile for meshing with the sprocket involute profile is pointed out，the optimization design method of silent chain plate inner profile based on the secondary variation is proposed. The multi-body dynamics models of silent chain transmission system are established，and the silent chain transmission system based on different design methods is compared and analyzed. The results show that the optimization design of inner-outer compound meshing silent chain plate inner profile based on the secondary variation could effectively reduce the polygon effect and meshing impact of silent chain transmission system.关键词：Equivalent chain plate
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发布时间：2022-10-20 - 摘要：A Direct-Driving Automated Mechanical Transmission （DAMT） for electric vehicles with integrated electromagnetic linear drive is proposes，and the shift performance is analyzed by simulation and experiment. The transmission combines the respective advantages of the direct drive technology and the mechanical transmission，and directly drives the two-speed integrated coupling sleeve to complete the shifting by using the electromagnetic linear driving device. In order to obtain the target of maximum shifting force and shifting force volatility，the parameters of the shifting actuator are optimized by the annealing particle swarm-finite element algorithm. The shifting mechanism of the electromagnetic direct drive transmission is studied for modeling and simulation of shift process in stages. The DAMT prototype and the test bench are built to perform the typical working condition shifting experiment. The experiment results show that under the condition of the electromagnetic direct-drive transmission with a speed difference of 220 r/min and a moment of inertia of the synchronous end of 0.04 kg
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发布时间：2022-10-20 - 摘要：A new type of cable-rod hybrid drive parallel mechanism is proposed，and the overall device model is built in SolidWorks. The inverse kinematics model of the mechanism is derived by using the space vector analysis method. The equilibrium relationship of the parallel platform under static state is analyzed，and the statics equilibrium equation is established. On this basis，the solution method of mechanism controllable workspace is discussed. Under the constraint condition of the given mechanism motion pair，the numerical simulation of the controllable working space of the moving platform posture is carried out to obtain the simulation image. The test platform of the cable-rod hybrid drive parallel mechanism is built. The posture transformation test of the moving platform is completed. The experimental results are compared with the kinematics model and the numerical simulation results of the workspace. The test results show that the relationship between the posture of the moving platform and the length of the cable meets the kinematics inverse solution model. The posture of the end moving platform can be transformed to the maximum posture deflection angle in the workspace simulation image. A theoretical foundation for the practical application and performance optimization of the follow-up institutions is laid by this study.关键词：Parallel mechanism
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发布时间：2022-10-20 - 摘要：In order to overcome the shortcomings of the parallel mechanism used in express delivery industry， such as small motion space and limited application scope，a 2 （2-UPR+RPU） series-parallel hybrid mechanism is proposed based on the 2-UPR+RPU low-DOF parallel mechanism. The inverse position solution and workspace analysis are carried out in order to be applied in industrial production. Firstly，the hybrid mechanism is modeled in SolidWorks，and its degree of freedom is obtained by analyzing the screw theory. Then，the position inverse solution of the mechanism is solved by continuous method. Finally，the motion simulation is carried out in SolidWorks by using CAD variable geometry method and the track data of the processing points are obtained，and the workspace is obtained by using Matlab software. The workspace of 2 （2-UPR+RPU） hybrid mechanism is much larger than that of single-layer parallel mechanism，and its shape is regular and symmetrical. The 2（2-UPR+RPU） hybrid mechanism has both the flexibility of series mechanism and the high rigidity and precision of parallel mechanism. Through corresponding program control，it can replace manual work.关键词：Hybrid mechanism
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发布时间：2022-10-20 - 摘要：A double closed loop 5-DOF manipulator arm is proposed， which adds a closed loop structure on the basis of（（2-UPS）+U）PU configuration to obtain a new topology configuration 2-UPS+（（2-UPS）+U）PU. The introduction of the closed loop structure enables the mechanism to obtain a higher carrying capacity and provides a new idea for the new topology configuration. The mapping of the velocity of the branch drive，the velocity of the swing angle of the branch and the generalized velocity Vo of the moving platform is derived. The decoupling matrix between the independent variable
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发布时间：2022-10-20 - 摘要：A new type of non-orthogonal arc tooth face-gear is designed. The arc tooth cylindrical gear is used as an imaginary tool to envelop the working tooth surface and transition surface of the face gear. The mathematical model of the face-gear is obtained in Matlab. The full tooth surface tooth surface equations of the non-orthogonal arc tooth face-gear is derived，and the realization of tooth surface visualization through Matlab programming which laid the theoretical foundation for the subsequent research on non-orthogonal arc tooth face-gears.关键词：Nonorthogonal;Arc tooth;Face gear;Design;Visualization
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发布时间：2022-10-20 - 摘要：The cylindrical gears are used to drive the traditional electric steering gear. There are many problems such as heavy weight，complex space structure and more transmission series，so the transmission efficiency is low. In view of the above problems，harmonic gear transmission is used instead of cylindrical gear transmission to determine the overall scheme，component structure. The Creo software is used to build the three-dimensional solid model of the transmission device，and the trial-manufacture of the principle prototype is completed after processing，manufacturing， installation and commissioning. The study results show that the scheme of applying harmonic gear transmission on electric steering gear transmission device is feasible，a foundation for theoretical and experimental research of optimizing electric steering gear transmission is laid.关键词：Electric steering gear
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发布时间：2022-10-20
Design· Calculation
- 摘要：The skiving cutting tool movement eccentricity error has obvious influences on skiving gear accuracy. Based on the theoretical and experimental study of skiving，the influences of cutting tool eccentricity error on the helix deviations and the tooth profile deviations of the workpiece machined by skiving and action mechanism are investigated. Firstly，experiments of skiving process method are carried out，which are focused on the skiving waves on the tooth flanks of the workpieces，it is found that the amplitude of the waves can be decreased by reducing the tool eccentricity error. Then，based on the experiment study，the theoretical analysis of the influences of tool eccentricity error on the helix deviations and the tooth profile deviations of the workpiece are carried out，and the wave generation mechanisms and periodic characteristic are investigated. Finally，based on the experiments and theoretical study，the design method of number of tooth of skiving cutting tool，which can be used to improve the gear skiving waves on the tooth surface of the workpieces is proposed.关键词：Skiving
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发布时间：2022-10-20 - 摘要：Small diameter turbodrill with reducer is widely used in the field of geological drilling，but the radial size of the turbodrill is strictly limited and the reducer requires a high output torque，so it is of great engineering significance to optimize the structure of the asymmetric gear to improve its contact strength. Taking the sun gear and planet gear in the
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发布时间：2022-10-20 - 摘要：With the wide application of planar sinusoidal ball movable teeth transmission in various industries，the study of its dynamic characteristics and vibration problems is also very important. Aiming at the torsional vibration model and its inherent characteristics of planar sinusoidal ball transmission mechanism，a 5-DOF torsional vibration mechanical model is established by using the lumped parameter method. Based on the undamped free vibration equation，the natural frequency and modal modes of the system are calculated. The sensitivity of the natural frequency of the system to the inertia and stiffness parameters is analyzed by the partial derivative method，and the structural parameters which have significant influence on the natural frequencies of the system are concluded. In order to avoid resonance between the system and the external excitation，the parameters with high sensitivity to the natural frequency of the system are modified to improve the operation stability of the system.关键词：Plane sine
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发布时间：2022-10-20 - 摘要：Aiming at the failure of slewing bearing in a certain type of vehicle-borne radar actuator，the service life of slewing bearing is studied according to its structural characteristics and operating conditions，and a life prediction method of slewing bearing based on finite element method is obtained. Using ANSYS Workbench to analyze the simplified three-dimensional model of slewing bearing，the contact stress and fatigue life of inner and outer raceway and rolling body of slewing bearing are obtained，which improves the calculation efficiency. The accuracy of the finite element method is verified by comparing the results of the finite element method with those of the Hertz contact theory and the actual work.关键词：Slewing bearing
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发布时间：2022-10-20 - 摘要：Taking the 3UPS-PU parallel mechanism，the experiment platform of sample package special test in the lunar exploration project as the study object，the error analysis model of 3UPS-PU parallel mechanism is established by using matrix differential method，which verified the correctness of the error analysis model from the macro to micro accordance with the volume error and single element of the pose error. And based on the results of single error analysis through the error model，the main error terms are analyzed，which could afford the reliable foundations for selection of parts manufacturing tolerances and its assembly levels. The method can not only solve a range of issues related to error analysis of 3UPS-PU parallel mechanism，but also apply to research and analysis of similar mechanism.关键词：Parallel mechanism
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发布时间：2022-10-20 - 摘要：Aiming at the problem of the failure of the downwind side gear teeth on the high-speed intermediate gear shaft of wind turbine gearbox，the fishbone analysis method is used to analyze the reasons of design，manufacture，material，assembly and operation maintenance. Based on the experimental research and simulation analysis method，it is determined that the failure of the gearbox is due to the lack of downwind direction in the assembly process of the gearbox. The control of bearing compression leads to the excessive clearance of bearings，which results in the eccentric load of axle gears.关键词：Wind power gearbox;Gear failure;Bearing clearance;Fishbone diagram
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发布时间：2022-10-20
Test·Analysis
- 摘要：The power curves of the oversized chains over 56B are deficiency in the ISO or GB standard. All the parameters of the oversized chains remain to be tested. A test machine based on the principle of closed power flow is developed for the oversized chains testing. The basic composition，technical parameters and testing range are introduced. The characteristics of the oversized chains under the condition of pressure spray oil lubrication over 56B，such as wearability，power capacity and other characteristics of running in different speed and load can be tested，the technical data for the chains developers is provided.关键词：Oversized
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发布时间：2022-10-20 - 摘要：The performance of differential has an important effect on vehicle passability and maneuverability. In order to determine the locking coefficient of the differential，a special test rig is developed，and a new test method is proposed. That is，the locking coefficient is measured under three working conditions of straight-line driving，low-speed turning and high-speed turning. The test results show that the locking coefficient of the differential is consistent with the theoretical value，the test results are accurate and reliable，and the performance test is completed well.关键词：Differential
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发布时间：2022-10-20 - 摘要：The GB/T 11365-2019 provides that the tooth contact pattern of straight bevel gear is agreed by both supply and customer，and there is no direct relationship between tooth contact pattern and gear accuracy classification. During developing a high lift straight bevel gear pair for a large passenger aircraft，the straight bevel gear pair designed according to ANSI/AGMA 2009-B01 standard，the figure of the tooth contact pattern is clearly marked in the drawing，the length，position，shape and other information，in the manufacturing process control of bevel gears also have certain requirements，a good contact state of the gearbox under any working load is finally realized，and the interchangeability of the gear pair is realized，and the concept of master gear and control gear is proposed. The advanced technology of high precision straight bevel gear machining is expounded from milling technology，gear blank，fixture，cutter，program，contact zone modification technology，heat treatment deformation control，etc.关键词：Contact zone
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发布时间：2022-10-20
Development·Application
- 摘要：A curvilinear cylindrical gear is a parallel shaft transmission gear that is not fully marketed. The teeth of this gear transmission have a circular arc curve along the longitudinal direction，it has non-axial force and good lubrication performance. The research status of the curvilinear cylindrical gears is analyzed in detail through a large number of related literatures，the processing methods of the gears，tooth surfaces modeling methods and contact characteristics are expounded. Finally，based on the existing research status，some suggestions for the future research direction of the curvilinear cylindrical gear are put forward.关键词：Curvilinear cylindrical gear
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发布时间：2022-10-20 - 摘要：The development and application of harmonic gear drive in recent years are briefly reviewed，the development of gear tooth profile and the main factors affecting the life of reducer are mainly expounded. In the traditional tooth profile，the tooth profile has undergone the development stage from the linear tooth profile to the arc tooth profile，and then to the double arc tooth profile，the meshing characteristic and fatigue life at each stage are analyzed. The representative teeth of the current products are "S" tooth profile，"P" tooth profile，"δ" tooth profile and so on. In recent years，thin wall and long life are the focus of research，and a large number of researches focus on stress research of cylinder，gear tooth and wave generator. On this basis，suggestions are given on the research direction of harmonic reducer that should be paid attention to in the future，that is，the research of tooth profile，the analysis of material microstructure，the research of processing technology，the establishment of theoretical system，the problem of large natural frequency fluctuation，the accurate analysis and calculation of tooth meshing force，the influencing factors of transmission accuracy，etc.关键词：Harmonic gear drive
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发布时间：2022-10-20 - 摘要：Gas turbine is a new generation of clean energy power plant with high power，high efficiency，small size and long life. Gas turbine gearbox is a device that transfers the output power of gas turbine to the working machine after deceleration and torsion increase，and it is one of the key supporting systems of gas turbine units. The development status of gas turbine and gas turbine gearbox at home and abroad is described. The typical structure of gas turbine gearbox and its advantages and disadvantages are analyzed and enumerated. The key technologies and research status of gas turbine gearbox development，such as transmission system dynamics research，planetary gear load sharing technology and gear modification technology，are summarized. The development trend of gas turbine gearbox and the problems needing further research are pointed out.关键词：Gas turbine gearbox
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发布时间：2022-10-20 - 摘要：The research history and current situation of involute spline is briefly summarized. The new development and application status of involute spline technology in recent years is more systematically introduced. It mainly focuses on study of design and development stage of involute spline，selection of reference standard of involute spline，calculation optimization and measurement of involute spline，as well as the research of fixture used for measurement，and share our measurement method. It is proposed to update the measuring equipment and improve the measuring accuracy，collaboration is needed to integrate software standards，carry out accurate calculation，remove conversion approximation and so on.关键词：Involute spline
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发布时间：2022-10-20
Review
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