最新刊期
期 12 ， 2016
- 摘要：The development trend of complex packaging machinery is used the multi- axis synchronous servo drive technology to replace the traditional mechanical transmission technology. For the packaging process execution end high- speed reciprocating motion requirements,a design method of multi bar mechanism by using the electronic cam driven is proposed. The curve planning method of the electronic cam is discussed. The mathematical model of the cam movement is established by the NURBS curve method,and the smooth cam motion curve is obtained. The simulation and experiments show that using the NURBS curve fitting method can meet the requirements of speed,acceleration and multi axis synchronization,so as to ensure the smooth and no impact of the push movement,and improve the output flexibility.关键词：Electronic cam;NURBS curve;Synchronization control
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发布时间：2022-10-20 - 摘要：To study the influence of multi- floating components on the load sharing of heavy load planetary gear system,taking a large wind power planetary gear system as the research object. The FE model of this system is established to analyze the load sharing. The load sharing change trend of the planetary gear with the change of planet carrier stiffness,planet gear error and the floating of the sun gear and the planet carrier,external load are analyzed. The results demonstrate that the load sharing of the system is better in the case of the floating sun and planets gear carrier at the same time. Reducing the stiffness of the floating support or increasing input load can effectively improve the load sharing capacity. The experimental verification of load sharing situation of multi- floating component planetary gear system under the change of external load and planet carrier support stiffness is carried out on the load sharing test platform.关键词：Multi-floating component;Planetary gear system;FE model;Dynamical load sharing
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发布时间：2022-10-20 - 摘要：The transmission system is the key components of the helicopter,the study and analysis of the dynamics characteristic and virtual simulation have an important function for the whole life cycle in every stage.The 3D model of the helicopter transmission system is established by CATIA software,the load under the typical working condition is calculated,and the virtual prototype model is built under ADAMS software. The kinematic simulation analysis of the model is carried out,the rotate velocity and the time and frequency domain curves of meshing force of the main meshing gear are extracted and analyzed,the simulation results are consistent with theoretical calculation results. The research work can provides the model and theoretical basis for structure optimize design and analysis of fatigue and forecasting life of the helicopter transmission system.关键词：Helicopter;Transmission system;Virtual simulation;Dynamics characteristic
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发布时间：2022-10-20 - 摘要：Aiming at motion error problems of walking robot in the actual movement,a geometric parameter model of the robot is established based on introducing structure of reptiles- like robot Mini Quad- Ⅰ. The relationships among the robot parameters error and the structure size and the trajectory error are discussed,the kinematics calibration model of this kind of robot is studied in detail. By measuring the change of the body posture and each joint movement angle,the structure parameters of the robot are calibrated,when the robot movements in given trajectory. The automatic calculation system for parameters calibration is developed,and parameters calibration process is illustrated with example. A foundation for establishing relatively accurate control models of the robot is laid by the research.关键词：Quadruped walking robot;Motion error;Kinematics parameter;Calibration model
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发布时间：2022-10-20 - 摘要：In order to realize the control for multi- range hydro- mechanical continuously variable transmission（ HMCVT） in tractor,the fuzzy adaptive PID control for multi- range HMCVT in tractor is studied.The transmission system dynamics model of tractor and fuzzy adaptive PID control model are established based on Matlab / Simulink platform. According to the actual deviation of the actual vehicle speed and the target vehicle,the fuzzy control method is adopted to automatically adjust the PID control parameters,so as to achieve the purpose of control. The fuzzy adaptive PID control simulation on the tractor dynamics model and comparison with the PID control simulation. The results show that the stronger adaptive ability and robustness of fuzzy adaptive PID control of tractor.关键词：Multi-range hydro-mechanical continuously variable transmission;Fuzzy adaptive PID control;Simulation;Robustness
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发布时间：2022-10-20 - 摘要：The speed ratio of EM- CVT can be adjusted by controlling the motor angle and the power source of speed ratio change is provided by a single motor. The control strategy based on Fuzzy- PID is proposed to improve the control precision of speed ratio control system and the fuzzy- PID is optimized by PSO algorithm. The Fuzzy PID speed ratio controller model is set up,whose parameter factors are optimized by the PSO algorithm to realize the optimization of the speed ratio control system. The simulation is carried out and the results show that the Fuzzy- PID controller optimized by PSO algorithm can improve the control precision of system and the performance of the speed ratio tracking performance.关键词：EM-CVT;PSO;Fuzzy PID;Speed ratio control
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发布时间：2022-10-20 - 摘要：Aiming at the problem that the fault feature of rolling bearing can be easily overwhelmed by random noise,a novel denoising method on the basis of local characteristic- scale decomposition and Fast Kurtogram（ LFK） is presented. Firstly,the signal is decomposed by local characteristic- scale decomposition（ LCD） and entropy difference spectrum is proposed to choose and reconstruct the component signals. However,the residual noise may still exist in the reconstructed signal. So in order to remove noise interference to some degree,the Fast Kurtogram is applied to enhance the filtering and denoising effect further. Meanwhile,and the bearing fault feature information is well preserved. At last,the validity of the method is tested and verified by the simulation signal and the inner ring fault signal of rolling bearing.关键词：LCD;Entropy difference spectrum;Fast Kurtogram;Denoising;Rolling bearing
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发布时间：2022-10-20 - 摘要：The signal acquisition is a prerequisite for fault analysis and diagnosis,but also the necessary condition in the fault diagnosis of wind turbine gearbox. At present,the most mature method is vibration signal analysis method,however,because the internal structure of the gearbox can not be destroyed,it can only lead to vibration sensor installed on the external wall of the gearbox. The sensors arrangement of gearbox will directly influence the quality of diagnostic accuracy. By using the immune algorithm to solve the problem of sensor arrangement in fault diagnosis of wind turbine,the gearbox vibration source coordinates is constructed,the optimal acquisition path of vibration transmission is calculated,the best measuring point is determined. The placement optimization of the measuring point for sensor is realized,an effective method for sensor arrangement is provided.关键词：Immune algorithm;Measuring point of sensor;Arrangement optimization;Wind turbine
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发布时间：2022-10-20 - 摘要：The meshing impact of teeth back which may lead to the phenomenon of low- transmission efficiency,poor accuracy and the decreased stability is studied by considering the teeth backlash,errors and deformation of the gears. Based on the finite element model of dynamic contact of the spur gears,the effects of rotate speed and load on the back meshing is obtained by simulating the meshing characteristic of the gear. The research result shows that both normal meshing and back meshing of gear teeth exist alternately in a certain speed and load condition. The impact of back meshing becomes serious with the increase of the speed of the driving gear. While,it may be weakened with the increase of the load applied on the driven gear within a certain level. When the phenomenon of back meshing happens in the meshing process,the contact force on the normal surface changes between zero and peak magnitude. At the same time,the actual meshing process of gear pairs is a regular cycling changes of normal meshing,mesh apart,back meshing,normal meshing. The study has a certain reference value for designing gear system in the aspects of reducing vibration and noise.关键词：Back meshing;Dynamic contact;Meshing impact;Mesh-apart;Contact force
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发布时间：2022-10-20 - 摘要：The mesh model for the conventional involute gear pair is developed. Then the mesh characteristic is solved and analyzed. Based on the mesh model and the calculated results,the effects of normal pressure angle on the meshing slip coefficient,tooth root stress,contact pattern,the maximum contact pressure and the variation of the mesh stiffness are investigated. The results show that the increase of the normal pressure angle tends to increase the bending strength,the contact strength and the ability to prevent scuffing when the normal pressure angle is less than 25°. But,when the normal pressure angle is larger than 25°,the above results will change slightly. Also,it will decrease the root stress when the normal pressure angle is less than 25°. However,when the normal pressure angle is larger than 25°,the root stress will become a little larger. The increase of the normal pressure angle also can decrease the contact ratio,improve the contact pattern and decrease the variation of the mesh stiffness. The results of this study can be applied to guide the normal pressure angle selection and design of the involute gear.关键词：Involute gear;Pressure angle;Mesh characteristic;Parametric analysis
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发布时间：2022-10-20 - 摘要：As a special type of bevel gear drive,the face gear drive has a brightening prospect in aeronautics due to its excellent confluence and shunt transmission performance. Through the FEA simulation of orthogonal spur face gear drive,the strength models available in the calculation of contact stress and bending stress of face gear and pinion are established with the application of orthogonal experiment and regression.关键词：Face gear;Strength;FEA;Orthogonal experiment;Regression
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发布时间：2022-10-20 - 摘要：The pressure generated by the compression of the trapped oil lead to a resistance moment,which will result in a certain oil churning power losses,when the external gear pump is working. In order to determine this part of losses,a calculation method of the oil churning power losses of external gear pump is presented. The two- dimensional simulation of a certain type of external gear pump is carried out by using dynamic mesh technology of CFD software FLUENT,and the change of the oil churning power losses in a period of the trapped- oil under different revolving speed and working pressure is analyzed. The results indicate that the oil churning power losses are mainly affected by the trapped- oil pressure,and increase along with the revolving speed and working pressure,which account for 0. 43% 5. 26% of the input power.关键词：External gear pump;Oil churning power loss;Dynamic mesh;Trapped-oil pressure
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发布时间：2022-10-20 - 摘要：The high precision gear processing must consider the influence of machining error on the meshing quality,based on the basic principle of the contact analysis of helical gear,the simulation of involute helical gear is realized by using the Matlab software,then tooth contact trace and the transmission error cure is obtained. By comparing the gear transmission error curve under different hob installation error,the sensitivity of the transmission error on different hob installation error is analyzed. The gear mesh quality will be connected with the hob installation error by the research methods of this article,which will provide the basis for subsequent finishing.关键词：Transmission error;Tooth contact analysis;Machining error;Helical gear
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发布时间：2022-10-20 - 摘要：In order to process the hardened face gear,and improve the application of face gear in aeronautics industry,the grinding process of face gear is studied. A worm grinding wheel for grinding process of the face gear is studied in design and dressing method. According to the meshing relationship of face gear,worm grinding wheel and medium gear,the coordinate systems of face gear,worm grinding wheel and medium gear are set up. Combing the relationship between the tooth profile equation and the coordinate transformation and using the enveloping theory,the tooth profile equation of face gear,worm grinding wheel and medium gear are deduced,the processing method of worm grinding wheel and face gear is obtained. Through the numerical computation method,the tooth profile simulation of face gear and grinding wheel is carried out,the 3D model of face gear,worm grinding wheel and medium gear are set up. The approach and principle of dressing are studied,the simulation of dressing process is carried out,and a basis of grinding process of face gear is provided.关键词：Face gear;Worm grinding wheel;Dressing
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发布时间：2022-10-20 - 摘要：The medical massage for massage therapist has high working strength,therefore the mechanical massage hands for medical massage has important application value. A mechanical massage hand is designed and completed,the thumb of the hand joint adopts steer engine drive,and four finger joints is driven by pneumatic flexible metamorphic mechanism. Therefore,in the process of massage to human body,it has higher flexibility and very good at the massage hand meet the important technical index of must have flexibility,the kinematic analysis of massage hand is completed. This massage hands should have good application prospects in the field of medical massage.关键词：Metamorphic mechanism;Medical massage;Driving joint;Massage hands;Steer engine
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发布时间：2022-10-20 - 摘要：Based on principles of gear meshing,the precise 3D parametric model of the involute gear is built by using UG,and the finite element model of five teeth is established according to the contact analysis theory,and the contact analysis of simplified model is completed by ANSYS Workbench. Changing the traditional empirical modification method and the software KISSsoft is used to carry out optimization design of gear modification parameters according to the results of finite element analysis. The tooth surface contact intensity and transfer error are taken as the optimization target to obtain the optimal modification values and the modification result is finally verified through the ANSYS Workbench.关键词：Gear;Contact analysis;Modification optimization;KISSsoft
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发布时间：2022-10-20 - 摘要：The feasibility of taking the plane steel ball transmission mechanism as a speed increaser is analyzed. Through building the dynamics model of a meshing pair of the presented transmission mechanism,the self- locking mechanism of a meshing pair is analyzed. The research results show that each meshing pair is unavoidably self- locking in a certain area. However,the plane steel ball transmission mechanism could be used to realize the speed increasing transmission by the tooth profile of meshing pair is modified since the transmission has multi- meshing pairs and every meshing pair is on different phase.关键词：Speed increaser;Plane steel ball;Movable tooth transmission;Self-locking mechanism
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发布时间：2022-10-20 - 摘要：The motion simulation model and finite element model of drill pipe handing manipulator are established respectively by using ADAMS and ANSYS,the movement simulation and strength analysis of the manipulator are carried out. The results show that the trajectory of manipulator is approximation level,and has no velocity fluctuations which can meet the stability requirement of manipulator in pipe moving work. When the claw is under linear horizontal load,the load of hydraulic pump increased with the displacement increase,more than a certain position,the load increased rapidly. When the manipulator sustained the maximum load in the limit position,the maximum stress occurred on the back arm and forearm,the hazard zone concentrated near the hinge hole. The obtained result can provides a reference for performance evaluation and structure optimization of drill pipe handing manipulator.关键词：Manipulator;Adams;Motion simulation;ANSYS;Strength analysis
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发布时间：2022-10-20 - 摘要：The power division and flexible pin technology are the key technology in the main gearbox of wind turbine. Through the analysis of a particular type of wind turbine gearbox,the calculation method of how to determine the main parameters relating to the power division and flex pin compartments is brought up and the feasibility of the method is checked by using simulation analysis.关键词：Wind turbine gearbox;Power flow division;Flexible pin
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发布时间：2022-10-20 - 摘要：The coincidence point distribution under transmission for different numbers of teeth on a lattice cage dust filter in the suction arm is analyzed by using Mathcad. From function image of 180°sin x and 180°sin（ 0. 75x） in the interval- 30 and 30,existing designs of gear ratio is found irrational,and then look for a high overlap matching gear. For providing the theoretical basis to improve the efficiency of cross- rotation mechanism suction arm rotation transmission,thereby the gear transmission ratio is optimized. Then,the amount of processing dust filter and the effects of dust are increased,and energy consumption is reduced,while saving operating costs.关键词：Round cage dust filter;Cross-rotation mechanism;Transmission ratio;Optimization
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发布时间：2022-10-20 - 摘要：Combining the optimization mathematical theory with Matlab,taking the double circular arc cylindrical gear drive as study object,the optimization design is carried out. During the optimal design process,regarded minimal centre distance and gear volume as optimization goals,the boundary and strength constraint condition is proposed,the optimal design model is established by determining the value of the parameters.Then,the program of the optimization is programmed,the optimization scheme is obtained through the function of fmincon and bnb20. Compared with the original design scheme,the centre distance is reduced by 24%,and gear volume is reduced by 27%,so the effect of optimization is significant,the necessary reference for design and type- selection can be provided.关键词：Double circular arc cylindrical gear drive;Optimal design;MATLAB calculation Programming
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发布时间：2022-10-20 - 摘要：The noise of automobile engine valve timing mechanism is one of the main sources of engine mechanical noise,which is directly related to the power performance of the engine. With the cylinder head anti drag system test bench,by using orthogonal design method,the noise characteristics of the engine in different lubricating oil temperature,oil pressure,rotational speed of the crankshaft are tested. A new means and methods to obtain the transmission noise characteristics of the timing is proposed. In the process of test,the emphasis should be put on the mechanical noise of the timing drive chain and the camshaft. Compared to other forms of chain transmission noise test,it is more close to the actual operating conditions of timing chain system. The research shows that it can effectively reduce the overall noise level of the timing drive system by changing tensioner hydraulic and lubricating oil temperature,which is of great reference value to the research and development of timing drive system.关键词：Automobile engine;Timing chain;Noise characteristic;Experimental study
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发布时间：2022-10-20 - 摘要：The dynamic transmission error of a straight bevel gear pair is tested and the relationship between the dynamic transmission error and the gear vibration is analyzed,with a straight bevel gear transmission system as the research object. The dynamic transmission error test system for the high speed straight bevel gear pair is developed and the transmission error curves are obtained. The dynamic property parameters of the gear pair are researched by the analysis of the experiment data with the signal processing approach. According to the comparison of the dynamic transmission error and the vibration behavior tested near the corresponding area of the gearbox,the results show,for the straight bevel gear pair,the shaft frequency components are the main frequency components of the dynamic transmission error,the low frequency components of the dynamic transmission error vary obviously with the rotation speed,the effect of the dynamic transmission error and the vibration acceleration near the supporting bearings on describing the dynamic responses are consistent.关键词：High speed;Straight bevel gear;Transmission error;Test and analysis
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发布时间：2022-10-20 - 摘要：In actual gear manufacturing,there is a large part of spiral bevel gears with big transmission ratio,and its driven gear cone angle is larger than sixty degrees. The above driven gear can be produced by precision forging technics,and the pinion can be produced by traditional face- milling method to match for the forging gear. According to the process method mentioned upon,the tooth surface machining parameters which ensure spiral bevel gear has good meshing performance is designed. And according to the accurate machining parameters,spiral bevel gear 3D model can be created. This 3D model can be used to make driven gear precision forging mould. A pair of spiral bevel gears is used as an machining experiment example,the driven gear is made by precision forging process,and the pinion gear is milled to match for gear,the mesh rolling test shows that the tooth surface contact bearings are good. The carrying out of this precision forging process is beneficial to improving the machining efficiency of spiral bevel gear,reducing energy consumption,enhancing the gear strength,it must has a broad application prospect.关键词：Spiral bevel gear;3D model;Precision forging;Machining experiment
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发布时间：2022-10-20 - 摘要：The gearbox is an important urban rail train transmission equipment. Aiming at the problem of the gearbox housing easily damaged caused by the vibration,by the Creo to create the three- dimensional modeling of box and transmission components,and then using the Workbench modal analysis module,the gearbox assembly finite element analysis is carried out,and through the test modal to verify the results of theoretical modal,and through the box harmonic response analysis and random vibration analysis,the dynamic response of the gearbox is obtained. The results show that the theoretical and the natural frequency and modal test results similar formation to verify the validity of the modal obtained by the finite element method,the modal analysis and the results should be displayed to adjust the gear mesh frequency to avoid resonance frequency by adjusting the number of teeth or motor frequency. The harmonic analysis results also show that the gearbox around 500 Hz has a more noticeable vibration response,and modal analysis shows the consistency of the results. The random vibration analysis indicates that reasonable gearbox structure design can encourage good external vibration response. Based on the above analysis results,propose that the adjustment of operating strategies and optimizing the box structure design to avoid resonance effects.关键词：Cabinet vibration;Three-dimensional modeling;Modal analysis;Harmonic response a-nalysis;Random vibration
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发布时间：2022-10-20 - 摘要：In order to investigate the vibration characteristic of ball screws,an end- block type ball screw is selected as an example,a vibration model of the ball screw which is capable of capturing the vibration in drive dynamics as the nut moves along the screw is established. Based on the stiffness and damping stiffness which considering the nut raceway and screw raceway contact interface lubrication,hybrid model of flexible ball screw is established. Then,the vibration data are collected and analyzed on the test bench of ball screw vibration and noise. Finally,the effect of varying the screw rotational speed and nut position on the ball screw vibration are investigated numerically and experimentally. The analysis indicates that the movable nut plays the role of supporting spring in the ball screw feed drive,therefore,the vibration of the ball screw is very sensitive to nut position changes.关键词：Ball screw pair;Stiffness and damping;Vibration model;Empirical decomposition
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发布时间：2022-10-20 - 摘要：Taking the type of automobile transmission shell as a research object,in order to analyze and judge the performance of an automobile transmission shell,the experimental modal analysis of the automobile transmission shell and finished product is carried out by using the experimental modal analysis technique,comparison the results of extracted the parameter of automobile transmission shell and finished product,the results show that,the automobile transmission shell and the finished product corresponding to each other under 1500 Hz,the modal frequency has a small change in a certain frequency band,the modal damping ratio of the finished product is higher than the auto transmission shell,this provides a revised proposal and an important technical support for the following research of automobile transmission shell.
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发布时间：2022-10-20 - 摘要：A gear- box is the important continuously variable transmission in light truck. The structure and shape of a gear- box is particular complex and the phenomenon of stress concentration exists. And the high stress caused by stress concentration will directly affects the lifetime of a gear- box,even leads to crack. The structure strength of gear- box is studied through the experiment of static torque loading. The data of stress-strain characteristics of the cast aluminum shell is collected. And those data are analyzed with unidirectional stress method to find the stress concentration positions of a gear- box in its practical working conditions. Those analysis provide an important experimental basis for designing and manufacturing gearboxes.关键词：Gear-box;Unidirectional stress;Stress concentration
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发布时间：2022-10-20 - 摘要：For a rocket artillery elevating mechanism planetary reducer,firstly the rigid dynamics model is built by using the software ADAMS and the rightness of the model is verified through dynamics simulation,then,the dynamic load in time- domain and frequency- domain for the key parts of the reducer are obtained.Secondly,the finite element modal of the reducer box is established and the forced vibration response of the reducer is calculated with the software LMS Virtual. Lab and its vibration noise characteristics is simulated by using the acoustic boundary element method. A foundation for further understand the dynamic performance of the rocket artillery elevating mechanism reducer is provided,and the technical support for the optimal design of vibration and noise reduction of this sort of reducer is also provided.关键词：Elevating mechanism planetary reducer;Dynamics simulation;Vibration and noise;Finite element
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发布时间：2022-10-20 - 摘要：The influence factors on the transmission efficiency of MPV car driving axle are analyzed by using the vehicle rear axle transmission efficiency test bench. After the experiment of the drive axle,it is found that the bearing is an important factor affecting the efficiency of the drive axle. The friction torque of bearing,bearing clearance and friction torque of the sealing ring are analyzed to find the main factor of friction torque.The results show that friction torque of the sealing ring,which is accounted for over 85%,is the main power consumer of the frication torque of rear axle. Moreover,the transmission efficiency of rear axle can be improved when bearing clearance increases in an appropriate way.关键词：Drive axle;Bearing clearance;Bearing seal;Transmission efficiency
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发布时间：2022-10-20 - 摘要：An approach to intelligent compound fault diagnosis of rolling bearing using multi- wavelet transform（ MWT） and convolution neural network（ CNN） was proposed. According to this approach,the vibration signals of rolling bearing are analyzed by using MWT of removed post processing,and the corresponding multi- wavelet coefficient branches are obtained. Then,all the multi- wavelet coefficient branches are used to form feature maps,and a multiple CNN classifiers is developed to identify the compound fault of rolling bearing.The tests for the proposed method are accomplished based on artificial bearing fault data sets,and the method is optimized,the vibration signals are analyzed by using MWT,the obtained multi- wavelet coefficient matrix is used to form feature map,and CNN is developed to make a comparative experimental study. The experimental results indicates that this method could effectively identify the compound fault of rolling bearing,and the improved method could effectively improve the fault recognition rate and reduce the training cost.关键词：Rolling bearing;Intelligent compound fault diagnosis;Multi-wavelet transform（MWT）;Convolution neural network（CNN）
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发布时间：2022-10-20 - 摘要：According to the requirements of tank bottom longitudinal seam welding system of the new generation launch vehicle,its working platform feeding system are designed. Considering the flexible influence between screw nut and at both ends of its bearing contact surface and pre- tightening force,its flexible modal finite element is established. By 10 orders modal analysis,its vibration mode and natural frequency are obtained,and the maximum error between considering contact surface flexibility and pre- stress influence and without considering these factors is 24. 6%. The corresponding critical rotate speed of the first order natural frequency is obviously larger than the maximum rotate speed required by the screw. Therefore,the resonance will not occur in the system. Moreover,through the experimental test,its double nut positioning pre- tightening scheme and the computing method are verified. The methods and basis for the design of large- scale feed platform are provided.关键词：Launch vehicle;Pre-tightening;Working platform;Flexible modal;Finite element
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发布时间：2022-10-20 - 摘要：In the six degrees of freedom flexible parallel platform using in optoelectronics packaging,the performance of the flexible hinge is an important influence factor on moving platform workspace and precision.According to Castigliano’s theorem and Lobatto quadrature formula,the mechanical model of the corner- filleted is established and the compliance matrix of flexible hinge is deduced. At the same time,the performance parameters of flexible hinge are defined,they are the rotation ability θ and rotation accuracy σ. On this basis,the impact of corner- filleted flexible hinge structural parameters L,d,r on its rotational capacity θ and rotational accuracy σ is calculated and analyzed,and it is verified by the finite element method. The results show that enhancing L and r,reducing d can improve the performance of flexible hinge. A strong basis for the flexible parallel motion platform design using in optoelectronics packaging is provided.关键词：Flexible hinge;Compliance matrix;Rotation capacity;Rotation accuracy;Structural parameter
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发布时间：2022-10-20 - 摘要：The extended finite element method（ XFEM） is investigated to calculate gear crack propagation. The crack propagation computer program are developed,and the correctness is verified with the aid of standard examples. The distance between crack propagation path and gear center as the evaluation indicator of tooth / rim fracture is proposed,the effect of rim thickness,web thickness,sizes and positions of web holes on spur gear tooth crack propagation path is investigated. The results indicate that,the decrease of rim thickness results in gear tooth crack propagation paths moving down to gear center integrally,which increases the occurrence of rim fracture. The decrease of web thickness results in gear tooth crack propagation paths moving down to gear center integrally,which increases the occurrence of rim fracture. The existence of web holes increases the occurrence of rim fracture and the larger is the hole,the greater is the occurrence. The preferred position of web hole lies in vertically below the tooth socket.关键词：Extended finite element method（XFEM）;Gear web structure;Crack propagation path;Tooth root;Computer program
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发布时间：2022-10-20 - 摘要：Based on the working conditions of the coal mine transport reducer and metallurgical blender reducer,the developments on prototype of the two stages reducer of hypoid- cylindrical gear is carried out. It is presented the scheme of design on the gear reducer,and it is carried on the optimization of the geometric parameter on the hypoid gear. The control of transmission performance on hypoid gear is carried out by the tooth contact analysis. The transmission performance experiments under no- load and several loads on the developed reducer is finished to obtain the data of temperature and noise of the reducer. The results show that the transmission performance of hypoid reducer is excellent,and the reducer has obvious advantages in behalf of realizing a high transmission ratio and the lightweight design of reducer.关键词：Gear reducer;Optimization design;Lightweight;Tooth contact analysis
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发布时间：2022-10-20 - 摘要：Aiming at the non- stationary feature of the rolling bearing vibration signal and the fault samples are always in a small number in its fault diagnosis,a rolling bearing fault diagnosis method based on improved Hilbert- Huang transform energy entropy and support vector machine is proposed. Firstly,the vibration signal in different condition is decomposed by improved empirical mode decomposition,and the intrinsic mode functions are obtained and sensitive mode functions are selected by the sensitivity evaluation method. Then,the energy entropy of sensitive mode functions serve as input vectors of support vector machine. Finally,by using support vector machine to identify the rolling bearing fault pattern and condition. The experiment results show that this method can identify rolling bearing fault patterns effectively and offer a practical method for its fault diagnosis.关键词：Hilbert-Huang transform;Energy entropy;Support vector machine;Rolling bearing;Fault diagnosis
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发布时间：2022-10-20 - 摘要：In view of the error influence of rigid structure,the flexible modeling technology is applied to drive system design of reducer. The finite element modeling and modal calculating about its parts are carried out by using ANSYS platform,and the flexible design of the reducer is realized through a way of replacing the parts’ MNF file,thus then a simulation model of the virtual prototype of flexible reducer is set up based on ADAMS /View platform. The driving rotational speed and load torque of the reducer are fitted with Step function,and then its flexible body dynamics simulation is carried out. The simulation results that more close to actual situation is calculated and analyzed,such as input and output torque,acceleration,dynamic load and 3D frequency spectrum,all of those provide some strong reference and basis for flexible design and precision analysis of mechanical drive system.关键词：Modeling;Reducer;Drive;Step function;Flexible body;MNF file
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发布时间：2022-10-20 - 摘要：The type of cylindrical index cam mechanism with different size roller is proposed on the basic of original cylindrical mechanism. Using the elastic deformation of small roller pin to constraint mechanism of axial vibration may occur. The small roller pin mechanics analysis model is established,by changing different parameters to analyze the deformation of the pin roller and to determine the deformation of pin roller on a certain condition. By the work above,the parameter table is obtained and the basis for accurate modeling and dynamics analysis in the future is provided.关键词：Index cam mechanism with different size roller;Model;Elastic deformation;Analysis
- 6
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- 90
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发布时间：2022-10-20 - 摘要：For the quality problem of white layer on nitriding teeth surface of turbine oil pump gear,the grinding teeth method and fixture fixing type of hobbing teeth are modified by researching its machining principle and process dimension. A series of optimized plan is proposed and the machining difficulty is solved.关键词：Gear;Nitriding;White layer;Grinding teeth;Hobbing teeth
- 5
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- 80
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- 1
发布时间：2022-10-20 - 摘要：A new novel robot for hand rehabilitation is designed to help patients to do rehabilitation training. Firstly,the human index finger joints are modeled and analysis are conducted on the coupling motion of index finger joints. A combined execute structure of link and joint is proposed,with link structure,the movement interference of adjacent fingers can be avoided and with joint structure,the control way can be simplified. The load on hand is decreased because of the driven module and the execute module are separated by using wirerope- noose transmission as the transmission way for the robot. Then,the 3D model of the rehabilitation robot is designed in Pro / E and the model is imported into ADMAS,and the kinematics analysis is carried out. The simulation results indicate the joints angles are all meet the requirements of index finger for daily movement and the designed structure of the robot is meet the requirements for rehabilitation training. Lastly,the mechanical property of wirerope transmission is analyzed and the calculation formula of tension in wirerope is calculated at arbitrarily space attitude.关键词：Hand rehabilitation robot;Wirerope-noose transmission;Link and joint;Tension calculation
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- 243
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发布时间：2022-10-20 -
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