最新刊期
      期 10 ， 2021
      本期电子书

        Review

      • Xiuhua Zhang,Huaiju Liu,Caichao Zhu,Peitang Wei,Shaojie Wu
        Vol. 45, Issue 10, Pages: 1-14(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.001
        摘要：With the development of wind turbine，high-speed railway，aero-engine and other large equipment towards the direction of high reliability，long life and intelligence，it has put forward higher requirements for the life of basic components such as gears and bearings. It is urgent to use more scientific and efficient fatigue life prediction method. The life prediction methods of mechanical components can be divided into physical failure model，data-driven model and fusion model（physical failure and data-driven model fusion） three types. With the development of components life prediction research towards high precision and high efficiency，physical model is difficult to meet modern needs due to its complexity，time-consuming and non-universal disadvantages. With the rapid development of machine learning，deep learning and other technologies，data-driven model has become a hot topic in the research of components fatigue life prediction of due to the advantages of no need to know detailed failure mechanism and accurate prediction results. In view of this，the fatigue life prediction method of components based on data-driven is described. The application of these methods in the life prediction of components is introduced，including neural network，support vector machine，random forest and deep learning，and the characteristics of each method are summarized，and the developing trend of the life prediction method of components based on data-driven is discussed. And a case study of gear contact fatigue life prediction based on GA-BP neural network is presented.  
        关键词：Data-driven;Components;Life prediction;Machine learning;Prediction accuracy   
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        发布时间：2022-11-10

        Theory·Reserach

      • Chunjun Chen,Xiang Zheng,Lu Yang,Linchun Zhou
        Vol. 45, Issue 10, Pages: 15-21(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.002
        摘要：In order to research the constriction resistance of the drum gear coupling of high speed EMU traction motor drive system，by using the geometrical analysis method，a mathematical model of the external tooth surface is established according to the structural parameters of the coupling. The relative angle of each tooth surface and the minimum clearance in the case of shaft inclination angle is calculated based on the coordinate transformation when there is an inclination between the shafts. Make use of the load distribution method to calculate the relationship between the load of each tooth and the total load of the coupling according to the flexural approximate differential equation of single tooth，according to the Hertz contact theory and the rough surface contact theory，the actual contact area and constriction resistance are calculated. The researches show that the inclination angle between the shafts is the extreme value when the minimum clearance of the tooth surface is zero. The greater the shaft inclination of the coupling，the greater the load on the single teeth，and the more uneven the load distribution on the tooth surface of different teeth. When the motor is in traction operation，the minimum actual contact area of the coupling is approximately 0.012 mm2，and the maximum is approximately 0.06 mm2. The total constriction resistance of the coupling is inversely proportional to the total torque. The coupling constriction resistance is between16.2 μΩ and 155.2 μΩ. The study of the constriction resistance can provide a certain theoretical reference for the analysis of the couplings galvanic corrosion in the future.  
        关键词：High speed EMU;Drum gear coupling;Galvanic corrosion;Contact area;Constriction resistance   
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        发布时间：2022-11-10
      • Shisen Lin,Lubin Hang,Baojun Zhang,Lusheng Zhou,Xiaobo Huang,Junrong Chen,Ziyu Liu,Pengcheng Zhang
        Vol. 45, Issue 10, Pages: 22-28(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.003
        摘要：The ring platform serves as the movement and operating benchmark for the online inspection of the nuclear reactor coolant pump bolts，its rapid and high-precision adjustment is the key to whether the bolt online inspection can proceed successfully. Aiming at the needs of adjusting the position and orientation of the ring platform in the radiation environment，a coarse and fine two-stage high-precision fast adjustment method based on the decoupling parallel mechanism is proposed. The first stage adjustment uses the 6-DOF decoupling parallel mechanism to coarsely adjust the ring platform. The second stage fine adjustment uses the 1T2R and 2T1R decoupling parallel mechanisms corresponding to the two independent position and orientation characteristic subsets to sequentially adjust the levelness and coaxiality of platform. The coarse and fine adjustment decoupled parallel mechanisms are synthesized based on the theory of position and orientation characteristic set. It is proposed that the fixed fulcrum of parallel manipulator can be constructed by means of the sponge-vacuum-device's absorbing on the smooth cylindrical wall of the nuclear pump body. Based on the sponge vacuum device，the parallel mechanism is constructed，which can realize the rapid installation，switching and disassembly of each parallel mechanism. The fast adjustment of coarse and fine two stages based on decoupled parallel mechanism provides new ideas for realizing the rapid and high-precision adjustment of the ring platform in the nuclear radiation environment.  
        关键词：Ring platform;Coarse and fine two-stage adjustment;Decoupling parallel mechanism;Sponge vacuum device   
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        发布时间：2022-11-10
      • Qikun Liu,Shengli Wu,Zhi Li,Xiaochun Jian
        Vol. 45, Issue 10, Pages: 29-35(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.004
        摘要：Under the action of alternating load，the gear is easy to generate fatigue crack fault in the tooth root，and the crack propagation will not only affect the transmission accuracy，but even cause serious safety accident and economic loss. Therefore，it is urgent to study the evolution law of tooth root crack propagation. For this，by using complex function method，the Westergaard stress function is constructed to analyze the complex stress field at the crack tip，and the critical condition of crack growth is determined according to the maximum circumferential tensile stress intensity factor theory. Considering the complexity of crack tip discontinuity and singularity in the process of crack propagation，the extended finite element method is modified and the finite element model of tooth root crack propagation is established to solve these problems. Study on the root crack nucleation point location and the crack propagation path of the relationship between the outside diameter of the web，the web hole and the corresponding location of the nucleation point in the gear matrix structure，the crack propagation law of different influencing factors is obtained and the accuracy and effectiveness of the modified finite element method is verified. The results greatly enrich the research on the evolutionary mechanism of tooth root fatigue crack propagation.  
        关键词：Gear;Crack propagation path;Modified XFEM;Influencing factor   
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        发布时间：2022-11-10
      • Da Min,Guangming Zou,Xingdong Wang,Wei Tang
        Vol. 45, Issue 10, Pages: 36-41(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.005
        摘要：Taking cylindrical spur gear as study object，a nonlinear dynamics model of planetary gear transmission system is established by using mass concentration method. Four influences factors，namely backlash，time-varying meshing stiffness，meshing damping and comprehensive meshing error，are considered in the model，the dynamics equations corresponding to the model are listed and solved by the fourth-order Runge Kutta method. By changing the size of the backlash，the response states of the system under different backlash sizes are obtained. Finally，the time displacement image of relative position error，phase plane diagram and FFT spectrum are used to reflect the effect of specific backlash size on gear vibration response.  
        关键词：Planetary gear transmission;Backlash;Nonlinear dynamics;Vibration response   
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        发布时间：2022-11-10
      • Weiliang Yan
        Vol. 45, Issue 10, Pages: 42-46(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.006
        摘要：By analyzing the inertia force and inertia moment in the plane of crank-group driving mechanism，the dynamic optimization balance model of the mechanism is established. Taking the crank-group mechanism of three crank pairs as an example，the specific optimization model is solved by using Matlab optimization toolbox. The results show that the dynamic optimization balance method of crank-group driving mechanism can greatly reduce the inertial force and moment of inertia of the mechanism，and the optimization balance only needs to add the balance mass of the determined mass at the determined position in the opposite direction of the crank length according to the optimization results just a couple of pieces. This method has high operability and practical application value，and has certain guiding significance for the rapid balancing and popularization of the mechanism.  
        关键词：Crank-group;Dynamic;Optimization;Balance   
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        发布时间：2022-11-10
      • Xuecheng Zhang,Zhendong Jiang,Yaochen Shi,Tianxiang Zhao
        Vol. 45, Issue 10, Pages: 47-50(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.007
        摘要：In order to study the influence of speed on the noise level of the V-ribbed belt three-wheel drive system，taking the 6PK V-ribbed belt as an example，a noise test device for the three-wheel drive system of the V-ribbed belt is built based on the acoustic array principle，and the time-domain signal and noise sound pressure distribution cloud diagram of the sound pressure in the transmission system of three wheels at different speeds are obtained. As the rotation speed increases，the noise in the V-belt three-wheel drive system gradually increases. The low-frequency noise caused by the lateral vibration of the V-ribbed belt gradually increases with the increase of the speed. The increase in the lateral vibration noise of the V-ribbed belt is measured by the Doppler laser vibrometer is caused by the increase in the amplitude of the lateral vibration of the V-ribbed belt. It can be seen from the noise sound pressure cloud diagram that the high frequency friction noise caused by the friction between the V-ribbed belt and the pulley increases with the increase of the speed，when the three-wheel drive system of the V-ribbed belt resonates，the transmission system the noise has increased significantly.  
        关键词：V-ribbed belt;Lateral vibration;Noise   
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        发布时间：2022-11-10

        Design· Calculation

      • Jinfan Li,Tianxing Li,Yulong Li,Meng Tian,Jingyuan Zhou,Ruiyao Zhang
        Vol. 45, Issue 10, Pages: 51-56(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.008
        摘要：The traditional modification design has some disadvantages such as complex calculation，uncontrollable tooth profile curve shape and unstable meshing performance，the pressure angle of the gear tooth profile has a great influence on the meshing force transmission performance. Therefore，a new tooth profile modification design method is proposed based on the distribution law of the pressure angle of the cycloid tooth profile. Based on the pressure angle distribution trend obtained by calculation and analysis，the mathematical model of tooth profile modification with straight-line method is established，and the function representation between the tooth profile pressure angle and the modification amount is deduced，the tooth contact analysis model is constructed，and the transmission error of modified cycloid-pin gear is obtained. Through the comparative measurement experiment of the tooth profile shape and transmission error of the cycloid，the correctness and effectiveness of the method proposed in the article are verified. This method considers the mutual influence between the pressure angle of the cycloidal gear tooth profile and the modification amount，and the technical problems of traditional modification method in calculation，processing，and active design are solved，and the trend of modification amount can be flexibly controlled，while ensuring the meshing performance，it obtains the design tooth profile that is closer to the theoretical cycloid.  
        关键词：Cycloidal gear;Pressure angle distribution;Modification amount;Straight-line method;Tooth contact analysis   
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        发布时间：2022-11-10
      • Pengcheng Zhang,Lubin Hang,Xiaobo Huang,Huibin Yang,Baojun Zhang,Lusheng Zhou,Junrong Chen,Ziyu Liu,Shisen Lin
        Vol. 45, Issue 10, Pages: 57-65(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.009
        摘要：The master-slave operation detection device with force haptic feedback function is an effective method to improve the online detection accuracy of the hollow bolts of reactor coolant pump （RCP） and avoid damage to human health caused by nuclear radiation. In the light of motion characteristics of the ultrasonic testing probe for the hollow bolt detection，a new type of haptic master operation parallel mechanism （4-HSOC{-Ri1//Ri2（-P（4R））//Ri3⊥Ri4-}） is constructed by the topology synthesis method of parallel mechanism based on position and orientation characteristics （POC） set. The forward and inverse kinematics of the mechanism is solved by vector equation method，and furthermore the motion characteristics and workspace of the parallel mechanism are analyzed and simulated，the work space matching analysis and experimental verification are carried out for the characteristics of the deep hole detection operation at the end. The moving platform of the master force haptic parallel mechanism possesses symmetric folding property and good rotating ability. It is suitable for deep hole vertical scanning operation and meets the requirements of the slave bolt detection device of reactor coolant pump. It provides the theoretical basis for hole matching，scanning task and motion matching of the master-slave bolt detection device for reactor coolant pump.  
        关键词：Hollow bolt detection;Force haptic device;Parallel mechanism;POC set;Workspace   
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        发布时间：2022-11-10
      • Shuang Wang,Hao Qiu,Gedong Jiang
        Vol. 45, Issue 10, Pages: 66-71(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.010
        摘要：In order to solve the problem that the tooth designed in plane has profile interference under the influence of spatial deformation of the flexspline，a bidirectional conjugate method considering the spatial deformation of the flexspline is proposed. The double-circular-arc tooth profile of circular spline is obtained through conjugate calculating of preset convex circular arc of flexspline at the front and back sections of tooth width. The concave circular arc profile of flexspline is obtained through the reverse conjugate calculating of convex circular arc profile of circular spline at the front section，and is combined with the preset convex arc to make up the tooth profile of flexspline. According to the results of harmonic drive contact simulation based on 3D finite element analysis，it is effective to avoid the profile interference by introducing the space deformation of flexspline into the tooth profile design.  
        关键词：Harmonic drive;Double-circular-arc tooth profile;Finite element analysis   
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        发布时间：2022-11-10
      • Bin Yang,Xiaodi Huang,Yongcheng Huang
        Vol. 45, Issue 10, Pages: 72-76(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.011
        摘要：Compared with traditional grinding wheels，grooved grinding wheels have many advantages，but the error of grinding wheel profile has certain influence on machining accuracy. Therefore，a grinding wheel profile modification manipulator for CNC grinding machine is proposed，and a simple and economical method for alignment measurement and static error compensation of the manipulator is designed. The modification manipulator consists of two linear rails of the horizontal guideway and the vertical guideway. The guides are driven by a high-precision ball screw connected to a DC servo motor with optical encoder feedback. A single point diamond dressing tool is installed on the vertical guide rail. The alignment measurement method used a micrometer and a digital reading of the grinder. By measuring the contour error formed by the manipulator，the motion error compensation method is verified experimentally. The results show that the static error compensation method reduces the profile error of the grinding wheel by 40%，to the range of ±10 μm.  
        关键词：CNC grinding machine;Profile modification;Error compensation;Groove grinding wheel;Grinding wheel profile   
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        发布时间：2022-11-10
      • Fen Liu,Nanxing Du,Hongqiang Sang,Shiming Yang
        Vol. 45, Issue 10, Pages: 77-84(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.012
        摘要：Aiming at the safety problem of grip force of the different surgical instruments with the same opening & closing angle in minimally invasive surgical robot，which is controlled by using the same master manipulator，the end-effector grip force of the surgical instrument is studied，a mathematical model is established to solve the end-effector grip force. The influences of the nonlinear friction among the steel cable and the guide pulleys，the motion coupling between the finger and wrist joints，and the creep deformation of the steel cable on the guide pulleys on the grip force are considered in the model. The mapping relationship between the motor current and the end-effector grip force under the corresponding opening & closing angle is obtained. At the same time，the grip force of the clamping suture needle is analyzed，and the relationships of the grip force and the motor current，and the pulling force of the suture needle and the motor current are obtained. The grip force model is simulated and researched by Matlab，the curves of the grip forces with/without friction and creep deformation，and the grip force and the pulling force of the suture needle are especially given. The simulation results show that the mathematical model of the grip force is closer to the actual situation，which provides a theoretical basis for effective and safe grip force control in future.  
        关键词：Surgical instrument;Motion coupling;Grip force;Friction;Creep deformation   
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        发布时间：2022-11-10
      • Jun Liu,Chengmin Wang,Feng Wang
        Vol. 45, Issue 10, Pages: 85-90(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.013
        摘要：A kind of obstacle surmounting multi-leg robot is designed，the robot has the characteristics of fast moving speed and strong obstacle surmounting. Leg mechanism design is one of the important factors that affect the motion characteristics of multi-leg robot. A new kind of leg mechanism of multi-leg robot is designed based on crank rocker principle. In order to ensure that the center of gravity does not change in the process of robot moving，the tread curve of tread is designed by Matlab software，and the influence rules of different size parameters of leg mechanism on tread curve，horizontal velocity and acceleration of the contact point of single tread and ground are analyzed. At the same，the auxiliary climbing mechanism of the multi-leg robot is designed，and the work flow of the multi-leg robot climbing over obstacles is analyzed. Finally，the feasibility of the mechanism design of obstacle surmounting multi-leg robot is verified by virtual prototype motion simulation and physical prototype test.  
        关键词：Multi-leg robot;Leg mechanism;Crank rocker;Kinematic analysis;Obstacle surmounting   
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        发布时间：2022-11-10
      • Jianqing Zhou,Fuzheng Qu
        Vol. 45, Issue 10, Pages: 91-95(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.014
        摘要：The joint motor is one of the core components of the foot robot，and its dynamic response directly affects the performance of the robot. Among them，the planetary reducer is a precision mechanical transmission mechanism，and its transmission accuracy is closely related to the deformation of key parts. Therefore，by using Adams，a rigid-flexible coupling dynamics simulation model of the joint motor is established to simulate the transient output characteristics during the startup process. In the model，the key parts are flexibly processed，and the motion pair constraints between the parts are set. The Hertz contact theory is used to calculate the contact stiffness coefficient of the planetary gear and the sun gear and the inner gear ring. The simulation results show that the dynamic characteristics of the joint motor are closely related to the acceleration time and inertial load. A larger acceleration time and a smaller inertial load are beneficial to improve its dynamic performance.  
        关键词：Joint motor;Planetary reducer;Dynamics simulation   
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        发布时间：2022-11-10
      • Pingxin Ji,Peng Song,Xinmin Mo,Zuba Wei,Hao Zhao
        Vol. 45, Issue 10, Pages: 96-99(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.015
        摘要：The compliance of the joint for exoskeleton is very important in adapting to the wearer's motions and human-machine compatibility. However，the conventional rigid or passive compliant mechanisms cannot achieve the purpose of active compliance due to the non-real-time feedback of the human-machine interaction forces. Therefore，an active compliant actuator of the knee joint is developed，using of the antagonistic driving principles and the force-position transformation of the slider-crank mechanism，which can not only implement the compliance of the traditional series elastic actuator，but also can obtain the real-time human-machine interaction forces. Finally，the feasibility and effectiveness of the compliant actuator are verified by tests.  
        关键词：Knee joint for exoskeleton;Compliant actuator;Torque estimation   
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        发布时间：2022-11-10

        Test·Analysis

      • Hao Gao,Jianjun Yang,Hua Dai,Dingjun She
        Vol. 45, Issue 10, Pages: 100-105(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.016
        摘要：Aiming at the vibration and noise problem of a helicopter main reduction casing，the dynamics simulation analysis of the main reduction transmission system model is performed to solve the dynamic meshing impact force generated by the spiral bevel gear during high-speed transmission. Taking the main reducer as the research object，based on the damping vibration reduction mechanism，the influence of adding foam aluminum damping material to the bearing seat on the vibration of the casing is analyzed. The vibration response of the casing is solved，and the influence of the aluminum foam material of different thicknesses on the natural frequency and modal damping ratio of the casing is studied. The influence of different installation positions of the damping layer on the vibration reduction effect of the damping structure of the bearing seat is analyzed. The calculation results show that the vibration acceleration peak of the casing at the meshing frequency is reduced by 14.89%. Adding damping materials to the bearing seat can increase the modal damping ratio of the casing and effectively suppress the vibration of the casing.  
        关键词：Damping vibration reduction;Damping ratio;Modal analysis   
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        发布时间：2022-11-10
      • Yile Chang,Kun Yang,Jie Wang,Yu Chen,Yan Wang
        Vol. 45, Issue 10, Pages: 106-113(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.017
        摘要：In order to solve the problems of low average transmission efficiency of direct drive electric vehicle and the structure of traditional two shaft two speed transmission is not compact enough，a planetary gear two speed transmission scheme for electric passenger vehicles is proposed. And the parameters of power transmission system are matched，through the AVL Cruise preliminarily，the rationality for the parameter matching is verified. According to the matching result，the structural parameters for the planetary gear two speed transmission are designed. And the transmission ratio and other key parameters are modified. The three-dimensional model for the transmission is established based on CATIA. The strength for the key components is verified. Compared with the common direct scheme，the results show that the acceleration time for the whole vehicle will shorten 0.31 s when driving 100 km，the maximum climbing gradient will increase from 34% of direct drive scheme to 37%，the maximum vehicle speed will increase by 21 km/h，and the driving range under NEDC condition will also increase by 18 km. So the planetary gear type two speed transmission can effectively improve the power and economy for the whole vehicle.  
        关键词：Electric vehicle;Transmission;Planetary gear;Scheme design;Parameter matching;Structure design   
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        发布时间：2022-11-10
      • Yuwei Liu,Ye Wang,Chongzhi Fu,Yuanzhi Sun,Hao Chen,Zixi Wang
        Vol. 45, Issue 10, Pages: 114-119(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.018
        摘要：In order to ensure the service life of slider and improve the shift quality，numerical simulation is carried out for the wear between the slider journal and the shift fork during gear shifting. A finite element model is established，and based on the heat transfer theory，the thermal boundary conditions of the shift fork and the slider are set，and the wear amount and temperature distribution cloud of the shift slider at the end of a single shift in the synchronization process is obtained. Based on the Archard wear theory，the wear amount at the end of a single shift is calculated. Through Box-Behnken design method，the finite element simulation is carried out through the required 17 experimental points，and the linear regression prediction model of the wear amount is obtained through response surface analysis，the influence of the shift force，rotation angle，and friction coefficient on the wear amount of the slider is analyzed. The research results show that the rotation angle has the most significant influence on the journal wear.  
        关键词：Neck journal of shifting slider;Wear loss;Shifting force;Rotating angle;Coefficient of friction   
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        发布时间：2022-11-10
      • Yueming Zhang,Bin Shao,Shuting Ji
        Vol. 45, Issue 10, Pages: 120-125(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.019
        摘要：In order to analyze the resonance response of RV gear reducer system，the natural frequency of RV gear reducer system should be determined first. Taking RV-320E gear reducer as the research object and considering tangential degrees of freedom of crank shaft and cycloid wheel rotation motion，the 16 degrees of freedom dynamic model of RV gear reducer is established by centralized mass method. The dynamics differential equation of the system is established by Newton's second law and the differential equation of fixed axis rotation，and the natural frequency of the system is calculated. The influence of the material properties of the parts on the first-order natural frequency is analyzed and the influence graph is drawn.  
        关键词：RV reducer;Torsional vibration;Dynamics model;Natural frequency   
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        发布时间：2022-11-10
      • Dongfei Wang,Shijun Liu,Lü Pangong,Jiqiang Li,Deming Meng
        Vol. 45, Issue 10, Pages: 126-131(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.020
        摘要：The addendum and root of involute gear are modified，and the modified gear and unmodified gear are placed on the contact fatigue tester for comparative test. The variation of micro pitting corrosion on the tooth surface is reflected by measuring the profile fluctuation deviation and the tooth surface morphology. The experimental results show that the size and area of micropitting corrosion of the modified gear are much smaller than those of the unmodified gear under the same number of cycles，the micropitting propagation rate of the modified gear is also much lower than that of the unmodified gear. When the gear fatigue failure occurs，the number of cycles of the profile modification gear is much higher than that of the unmodified gear. It can be concluded that the profile modification greatly improves the anti micropitting ability and contact fatigue property of the gear.  
        关键词：Involute gear;Profile modification;Micropitting;Contact fatigue test   
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        发布时间：2022-11-10
      • Junbei Ma,Qinhao Zhang
        Vol. 45, Issue 10, Pages: 132-136(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.021
        摘要：In order to study the problem of fatigue crack growth of 20CrMnTi gear steel，the material 20CrMnTi is made into compact tensile specimens，and the fatigue crack growth test with load ratio R=0.3 is carried out on the fatigue tensile testing machine. Then use the numerical simulation software Abaqus to numerically simulate the fatigue crack growth process. The results show that the numerical simulation results and the experimental results have the same changing trend，and the difference between the two is within the allowable range of error. The numerical simulation method can well describe the fatigue crack growth process of compact tensile specimens. The research results provide an effective test and simulation analysis method for the study of the fatigue crack growth process and fatigue life of 20CrMnTi gear steel.  
        关键词：20CrMnTi;Fatigue crack growth;Fatigue life;Fatigue crack growth rate;Crack tip stress intensity factor   
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        发布时间：2022-11-10
      • Xiaodan Huang,Bang Pei,He Guan,Xiangyang Qiao,Youhang Fan,Shipeng Song
        Vol. 45, Issue 10, Pages: 137-143(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.022
        摘要：Taking a subway gearbox in service in China as the research object，a computer virtual prototype is constructed and a rigid-flexible coupling model with a flexible gearbox is constructed by using finite element software，the vibration signal characteristics of different measuring points are discussed，and the vibration characteristics of the gearbox body are analyzed under the change conditions of the number of broken teeth，the torque and the speed. The results show that the closer the measuring point is to the axis，the more sensitive it is to the impact energy，but the relative frequency domain characteristics are fuzzy. The increase of the number of broken teeth，torque and speed will lead to the aggravation of vibration，and presents different vibration characteristics locally. The research results have certain reference value for the simulation and experimental research of subway gearbox.  
        关键词：Gear tooth broken;Metro gearbox;Rigid-flexible coupling;Dynamics simulation   
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        Development·Application

      • Xiangmin Chen,Meng Duan,Qi Li,Guoqiang Shu,Kang Zhang,Luping Li
        Vol. 45, Issue 10, Pages: 144-150(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.023
        摘要：Aiming at the problem that is difficult to extract the fault features of gears under variable working and strong noise conditions，a fault diagnosis method based on adaptive time-varying filtering（ATF） and angle domain synchronous average（ASAD） is proposed. By combining ASAD and ATF，the signal after noise reduction is analyzed by order spectrum，and the local fault of gear can be diagnosed by modulation side frequency band in order spectrum. The simulation data and the data analysis of the variable speed gearbox test bench show that the proposed method has a good signal analysis adaptability for the gear vibration signals under the variable speed condition，and can not only filter out noise interference well，improve the noise suppression effect in the pass band，but also effectively highlight the gear fault characteristics under the variable speed condition.  
        关键词：Adaptive time-varying filtering;Angle domain synchronous average;Order analysis;Variable speed gear;Denoising;Fault diagnosis   
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      • Tao Chang,Yongqiang Xiong,Qiang Chen
        Vol. 45, Issue 10, Pages: 151-156(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.024
        摘要：Reliable dynamic simulation model is an important means of vibration improvement. Taking the dynamics model of 5.2 MW wind turbine gearbox bench transmission chain as an example，the dynamics modeling，response evaluation and calibration are described based on the empirical modeling methods in the industry. Based on the sensitivity optimization method，the gear meshing dynamics model is corrected，and the vibration response accuracy of the corrected dynamics model is better，indicating that the empirical modeling method combined with the sensitivity optimization method can establish a relatively reliable dynamics model，and it is an effective method.  
        关键词：Wind turbine gearbox;Dynamics model;Calibration;Model correction   
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      • Shuaixu Ji,Yongguo Liang,Huimin Hao,Li'na Li,Jiahai Huang
        Vol. 45, Issue 10, Pages: 157-163(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.025
        摘要：Aiming at the wrist movement dysfunction and rehabilitation training problems of stroke patients，a wrist rehabilitation device based on a coaxial spherical parallel 3RRR mechanism is proposed. The device is driven by three motors，and the end effector can realize spherical motion to simulate the three-degree-of-freedom compound motion of the wrist and realize wrist rehabilitation training. In order to achieve the purpose of compact design，a design scheme of three-axis coaxial spherical parallel mechanism and synchronous belt transmission is adopted. On this basis，the inverse kinematics mathematical model of the wrist rehabilitation device is established，and the relationship between the motor input angle and the output pose of the robot end is obtained，and the robot working space is determined，the maximum angle of rotation around the X axis is 32°，the maximum angle of rotation around the Y axis is 37°，and the full rotation around the Z axis. Finally，an experimental prototype is processed for experimental verification. The experimental results show that the device runs smoothly and there is no jamming in the working space.  
        关键词：Wrist rehabilitation device;Structural design;Kinematics analysis   
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      • Wei Wei,Yunpeng Li,Yanshuai Yang
        Vol. 45, Issue 10, Pages: 164-169(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.026
        摘要：The vibration-based methods have been widely used in the tooth root crack fault diagnosis of planetary gearbox. Compared with traditional transverse vibration signal，torsional vibration signal is not affected by the modulation of time-varying transmission path in theory，so its frequency component is simple and it is easy to extract fault features. The torsional vibration signal extracted from dynamic model is analyzed to realize the fault diagnosis of tooth root crack fault. Firstly，the rigid-flexible coupling model of healthy planetary gearbox is established and verified. Then，based on healthy planetary gearbox model，three typical crack fault models are established，and the dynamic response signals are extracted. Finally，tooth root crack fault is diagnosed by analyzing transverse vibration signal and torsional vibration signal. The results show that torsional vibration signal is feasible to diagnose planetary gearbox crack fault，and has more advantages than traditional transverse vibration signal.  
        关键词：Rigid-flexible coupling model;Tooth root crack failure;Torsional signal   
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      • Yibing Chen
        Vol. 45, Issue 10, Pages: 170-175(2021) DOI: 10.16578/j.issn.1004.2539.2021.10.027
        摘要：In view of 40Cr material chain pin，in order to meet the requirements of its comprehensive performance requirements of shear strength and wear resistance under different working conditions，it is necessary to master the relationship between different surface induction hardening requirements and shear strength of chain pin. Through set different requirements for surface heat treatment of pins，the shear strength test is carried out，and the surface induction effective depth of hardening case，the relationship between shear strength and surface hardness is comprehensively analyzed. And through the establishment of this relationship on the basis of the size of the parts suitable parameters，achieve good matching equipment use function requirements. The practice shows that good results can be obtained in the design and application of pins of bucket elevator chain in cement industry by mastering the relationship between effective hardening layer depth，surface hardness and shear strength.  
        关键词：Chain pin;40Cr;Hardness;Effective hardening case depth;Shear strength   
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