最新刊期
期 8 ， 2018
- 摘要：The cylindrical sine oscillating tooth transmission mechanism has the characteristics of small radial size,compact structure and high transmission efficiency. However,due to the complexity of the space sine curve groove,it is difficult to process and install,and the closed inner cavity is not conducive to heat dissipation. The research adopts the fixing output,holder,no eccentric plane sinusoidal steel pin drive mechanism,with good heat dissipation,the lack of space sine reducer is compensated. By analyzing the working principle and transmission characteristics of the plane sine steel pin drive structure,the method of judging the output rotation direction is obtained,and the formula of its transmission ratio is deduced. The kinematic characteristics and accuracy of the device are verified by kinematics simulation,the basis for the design and application of the mechanism is provided.关键词：Plane sine;Motion simulation;Oscillating tooth drive;Reducer
- 4
- |
- 131
- |
- 2
发布时间：2022-10-20 - 摘要：The stress concentration effect of surface topography plays an important role in the fatigue properties of gears. The quantitative analysis method of the effect of surface topography on gear fatigue performance is the basic work of an in-depth study of the surface integrity of gears and the anti-fatigue manufacturing. Taking the spur gear with grinding as analysis object,and a method to estimate the fatigue life of tooth root bending fatigue with the surface topography is presented. The risk area of tooth root is obtained by finite element analysis.The risk area of the tooth root is measured by the white light interferometer, the statistical distribution parameters and the exponential autocorrelation function is obtained according to the surface topography,and using them to reconstruct the surface topography needed for the finite element calculation. Based on the finite element method,the stress concentration effect of tooth root surface topography is analyzed,and the fatigue life of tooth root is estimated based on the S-N curve of materials,and the quantitative relationship between the roughness Ra and the bending fatigue life of the tooth root is given.关键词：Roughness Ra;Grinding;Finite element;Gear;Bending fatigue life
- 14
- |
- 190
- |
- 1
发布时间：2022-10-20 - 摘要：Based on the fractal theory and Hertz contact theory,the establishment of fractal model for tangential stiffness for contact surface of cylindrical gear with variable hyperbolic circular-arc-tooth-trace（ VH-CATT） is presented. This model is obtained by introducing the equation of critical contact area of elastic and plastic deformation of asperity and employing the surface contact coefficient of two ellipsoids to modify the asperity distribution function. The rationality of the surface contact coefficient is proved by numerical simulation,and the influence of the main parameters（ such as normal load,fractal dimension,roughness amplitude,tangential load,material propertied parameters） on the tangential stiffness is analyzed. The results are as follows,the normal load is proportional to the tangential stiffness,but when the fractal dimension is not the same,there is a big difference between them. The tangential stiffness first increases and then decreases with the increasing of the fractal dimension,and reaches the maximum when the fractal dimension is 1. 85. The tangential stiffness decreases with the increasing of the roughness amplitude and the tangential load,and increases with the increasing of the material propertied parameters. The model provides a theoretical basis for the further study of the tangential stiffness for contact surface of VH-CATT.关键词：Fractal theory;Hertz contact theory;Cylindrical gear with variable hyperbolic circular-arctooth-trace;Tangential stiffness;Numerical simulation
- 4
- |
- 119
- |
- 4
发布时间：2022-10-20 - 摘要：In order to improve the working efficiency and stability of industrial robots,the trajectory of the robot is optimized. In the robot task space,the NURBS curve is used to describe end effector trajectory,the algorithm of the inverse kinematics of the robot is used to transform the task space trajectory into the joint space.A constrained backbones multi-objective particle swarm optimization algorithm with adaptive penalty function is proposed to optimize the time,velocity,acceleration and jerk of the industrial robot. The algorithm uses the adaptive exponential penalty function to deal with the constraints,which help to guide the algorithm to enter the feasible area faster,and search better target value. Finally,the correctness and validity of the proposed algorithm are verified by robot machining experiment.关键词：Robot;Trajectory optimization;PSO;Multi-objective optimization algorithm
- 4
- |
- 451
- |
- 9
发布时间：2022-10-20 - 摘要：On the basis of the study on the circular-arc-tooth-trace cylindrical gear,the milling method of the elliptic-arc-tooth-trace cylindrical gear which can realize whole teeth width meshing is proposed. By analyzing the ideal geometric parameters,the equations of tooth surface and contact ratio are deduced. The forming processes of the machining tools and elliptic-arc-tooth-trace are analyzed by the rack and pinion model,and the milling principle is put forward according to which the milling of the gear is completed. The profiles of the gear machined by the oblique mounting tools are all involute in the radial sections,and the expansion curve of the tooth trace on the reference cylindrical surface is part of the ellipse. The convex and the concave tooth trace have the same geometric parameters. The processing principle can completes the high-efficiency milling of the gear,and also can be used for grinding.关键词：Elliptic-arc-tooth-trace;Geometric parameter;Circumferential modulus;Milling
- 5
- |
- 119
- |
- 1
发布时间：2022-10-20 - 摘要：Taking the double clutch transmission gear system as the research object,the virtual prototype model of the gear transmission system is established by using Romax software. The bearing capacity,contact spot and transmission error of the unmodified first gear are analyzed. Based on the theoretical basis of helical gear axial modification and tooth profile modification,the optimum three-dimensional comprehensive modification parameters of the first gear are designed by applying the optimal Latin sampling principle. Then,the optimal three-dimensional modification parameters are obtained with the help of the neural network and genetic algorithm. The simulating calculation results indicated that the three-dimensional modification of the gear can greatly reduce the gear contact stress,optimize the gear contact spots and reduce the meshing transmission error.The comparison of the results before and after optimization also proved the effectiveness of this method and it can be used as a reference for optimum design of transmission gears.关键词：Transmission;3D modification;Neural network;Genetic algorithm;Transmission error
- 4
- |
- 129
- |
- 3
发布时间：2022-10-20 - 摘要：The gear operating mechanism is one of the core components of the vehicle and the main control carrier for the operation of the vehicle. As the traditional gear operating mechanism has some defects such as single function,complicated operation and limited scope,a new structure design plan is created by related tools of TRIZ after a deeply research of TRIZ in its theory and method system,which makes the new mechanism a great advantage in volume,function,universality,reliability and other aspects. Ultimately,the purpose of accomplishment of the core structure design and optimization of product performance is achieved. Compared with the existing products, the new gear mechanism has characteristics of smaller volume, higher functional integration,higher reliability and better versatility.关键词：Gear operating mechanism;TRIZ theory;TRIZ tool;Structure design
- 4
- |
- 148
- |
- 2
发布时间：2022-10-20 - 摘要：By studying the clutch of parallel hybrid electric vehicle,the state judgment model and working process model based on logic threshold control strategy are established. The operation control principle of clutch in parallel hybrid electric vehicle is analyzed and the control model is set up. The feasibility of the logic threshold control in the clutch control of parallel hybrid electric vehicle is simulated on the Matlab/Simulink platform about clutch state judgment and working process. The result shows that the logic threshold control strategy can effectively judge the working state of the clutch,and then perform the work of shifting,braking and energy switching of the clutch in the parallel hybrid electric vehicle.关键词：Hybrid power;Logic threshold;State judgment;Clutch;Control
- 4
- |
- 136
- |
- 1
发布时间：2022-10-20 - 摘要：Based on the principle of human engineering,the eight-link mechanism with posture transformation of sitting and lying is designed. In order to ensure the stability of the mechanism and obtain better practical performance,the optimization design of the eight-link posture transformation mechanism is carried out.According to the process characteristic requirements,the specific constraint conditions and the optimization target of the eight-link posture transformation mechanism,the mathematical model of eight-link mechanism is constructed,the optimization design model of eight-link mechanism is established by using the ADAMS/View model,the optimization design of eight-link mechanism is carried out. From the results of the optimization design and the angle of the connecting rod,speed and acceleration curve before and after optimization,the optimization design coincides with the corresponding principle of human engineering, meeting the design requirements and purpose of the eight-link posture transformation mechanism.关键词：Posture transformation;Eight-link mechanism;Optimization design;Adams
- 4
- |
- 171
- |
- 1
发布时间：2022-10-20 - 摘要：In order to accurately predict the internal flow field and drag torque characteristics of the hydro-viscous clutch,with the flow field of double circular groove clearance as the research object,based on the principle of hydrodynamics and the Newtonian internal friction law,a two-phase flow CFD mathematical model considering cavitation effect is established,the fluid field is numerically simulated by FLUENT,and the influence of different rotational speed,inlet pressure and film thickness on field distribution,pressure distribution and drag torque characteristics are studied. The results show that the velocity distribution is inhomogeneous,and the fluid with the same direction of rotation has high velocity and has the function of diversion. The cavitation occurs in the intersection of the groove,the higher the speed,the larger the film thickness,the more the cavitation phenomenon. The high pressure region occurs at the entrance,and the pressure decreases with the radial direction,the negative pressure effect is generated at the outer edge. The bearing capacity is approximately linear with the rotation speed. The higher the rotational speed,the more obvious the shear stress increases. When the speed is less than（ 1 400 1 600） r/min,the drag torque is approximately linear with speed and then decreases slowly when reaching a certain peak. With the film thickness decreases,the drag torque is improved,and its peak point corresponds to a higher speed.关键词：Hydro-viscous clutch;Cavitation effect;Flow field distribution;Drag torque
- 2
- |
- 57
- |
- 0
发布时间：2022-10-20 - 摘要：By installing spring-dampers in the active joints,the multi-dimensional damping platform is set up based on the 3-PCR parallel mechanism. The kinematics equation of the 3-PCR parallel mechanism is derived and the workspace is analyzed. The radii of the upper and lower platforms,the bar length and the angle between the bar and the lower platform are chosen as the optimization variables to investigate their influence on the maximum sphere workspace. The above-mentioned parameters are optimized by genetic algorithm so as to obtain the vibration platform which meets the particular demand of the equivalent stiffness which is nearly constant when the vibration amplitude is small. The equivalent stiffness of vibration reduction platform in engineering application can be realized by using this design method. The presented design process of equivalent stiffness provides a novel approach for the vibration reduction platform design based on parallel mechanism.关键词：Parallel mechanism;Multi-dim vibration isolation;Optimization design;Equivalent stiffness;Genetic algorithm
- 3
- |
- 86
- |
- 2
发布时间：2022-10-20 - 摘要：A method for determining the mesh stiffness of internal gears is proposed by using a combination of finite element method and the contact theory. The global deformation of contact point is separated by a full finite element model and a partial one. The local contact deformation is calculated by using the analytical formula for a line contact problem. The mesh stiffness and load distribution can be obtained after solving the nonlinear contact equilibrium equations. Compared with the conventional finite element method,the proposed method has higher computational efficiency and stability. And it also overcomes the disadvantage that the analytical method is difficult to consider helical gears and different gear ring structures. Then the influences of constraints number and thickness of ring gears on the mesh stiffness are analyzed. This method can provide effective guidance for the design of the strength and dynamic characteristics of the internal gears.关键词：Internal gear;Mesh stiffness;Finite element method;Contact theory
- 5
- |
- 442
- |
- 1
发布时间：2022-10-20 - 摘要：To shorten the transmit route of shift force,improve transmission efficiency,a kind of electromagnetic direct-drive transmission（ D-AMT） is proposed,in which the actuator could drive sleeve shift directly for shifting. The finite element analysis model is established in JMAG to optimize the structure of actuator,the math model of shifting,researched the shifting parameters of D-AMT is established,the influence factors of shifting is analyzed and the influence of shift parameters on shifting performance is researched. The results show that the mass of actuator is 1. 313 kg,which decreased 26% compared with conventional AMT. At the typical working condition of pure electric vehicle（ difference of rotary speed is 500 r/min and the moment of inertia is0. 1 kg·m2）,time for shift is 0. 29 s,the shift shocks are 4. 9 m/s3 and 0. 695,which meet the requirement of shifting. The D-AMT provide a new program of the transmission innovation,which will develop pure electric dynamic transmission technology.关键词：Electromagnetic direct-driving transmission;Structural parameter optimization;Electromagnetic analysis;Shifting performance
- 3
- |
- 436
- |
- 2
发布时间：2022-10-20 - 摘要：The magnetic coupler produces eddy current in the conductor by permanent magnet magnetic field to realize the transmission of torque and rotational speed,while the eddy current loss will lead to permanent magnet temperature rising. When the temperature is higher than the temperature of the permanent magnet demagnetization,it will lead to irreversible permanent magnet demagnetization and magnetic coupling loss of working ability. An outer rotor is designed to be the magnetic coupling of the rotor of the inner rotor. The relation among the output speed,the torque and the coupling length is obtained by using ANSYS for electromagnetic simulation analysis. Based on the theoretical analysis and simulation calculation,the number of magnet and air gap length on the influence of the eddy current loss is also verified,and a including heat dissipation fin and heat dissipation structure of centrifugal fan is devised. By analyzing the Flow Simulation,the heat dissipation effect of the heat dissipation structure on the magnetic coupling can be verified,and the permanent magnet can be stabilized and operated in the long term.关键词：Magnetic coupling;Eddy current loss;Operating characteristic;Heat dissipation structure
- 3
- |
- 84
- |
- 2
发布时间：2022-10-20 - 摘要：The light weight design of the reducer is one of the most important research topics in the field of mechanical transmission,the box is a very important part of the reducer. Because of its design method,few scholars have studied the stiffness,structural strength,fatigue reliability and the overall dynamics of gear. An example of the reducer box of a beam pumping unit is taken as an example,the curve of material is fitted,the stress-strain of the gearbox is analyzed,load spectrum of gear and crank in box is calculated,the fatigue life of the decelerated chassis is evaluated by the rain flow method in n Codes software. The problem of the fatigue life analysis method of the box is studied,which lays the foundation for the light weight design of the rear reducer box.关键词：Beam pumping unit;Reducer;Box alternating stress;Fatigue life evaluation;Rain flow method
- 7
- |
- 146
- |
- 5
发布时间：2022-10-20 - 摘要：The optimization design for solving trapped-oil pressure relief of gear pump under higher speed is studied,taking the modulus,tooth number and modification coefficient as optimization variable,by the analysis of the maximum trapped-oil volume and maximum relief area,the two objective functions of are established releasing the trapped-oil pressure. Combining with the current requirements of the flow pulsation rate and the pump volume per unit rated flow and the radial force corresponding of external gear pump,the optimization model is built by using the SUMT technology that full name is sequential unconstrained minimization technique.Aiming at the result before optimization and after,the simulation analysis and verification of trapped oil pressures are respectively carried out. The results indicate that,the larger the modulus is and the smaller the tooth number and the modification coefficient are,the larger the maximum relief area is and the better the relief effect of trapped-oil pressure is. The smaller the tooth number and the modification coefficient are,the larger the maximum trapped-oil flow is and the worse the relief effect of trapped-oil pressure is,so an optimization problem is existed. The simulation result of an example is consistent with the experimental results provided by the literature before the optimization design,and the error between the experimental results and the simulation results is controlled in near 4. 9%,the reliability of the trapped-oil model is validated. After the optimization design,the value of the maximum trapped-oil pressure is reduced by 65. 41%,the relief effect of trapped-oil pressure is obvious.关键词：Gear pump;Trapped-oil performance;Model;Flow;Relief area;Optimization design
- 3
- |
- 133
- |
- 1
发布时间：2022-10-20 - 摘要：Considering the influence of deformation and displacement of supporting device on modification results,the gear modification is carried out by using KISSsoft analysis software,the gears are modified in generally drum shape and spiral with drum shape respectively,according to Weber slice theory,the stiffness matrix of displacement of tooth contact is established,by using the way of permutation and combination of incremental,the Hertz pressure stress,transmission error,peak load distribution coefficient of tooth meshing performance data of gear under different amount of modification are obtained,considering the deformation and displacement of the supporting device of the gear system accords with the actual working environment,comparing the two kinds of modification of gear meshing performance,contact stress,transfer the error of peak,longitudinal load distribution coefficient than the average crown modification to the tooth surface with drum shaped spiral gears,gear modification in improving the full use of the carrying capacity essential.关键词：KISSsoft;Support device;Gear modification
- 7
- |
- 291
- |
- 1
发布时间：2022-10-20 - 摘要：The time-varying meshing stiffness is an important parameter of the planetary gear failure mechanism. In considering the relationship between the base circle and the dedendum circle under the condition of the number of teeth for parameters,an improved model of cantilever beam is established. For each pair of planetary gear meshing time-varying meshing stiffness are discussed,considering the wheel body stiffness,energy method is applied to solve more accurate tooth meshing stiffness. On the basis of this method,the timevarying meshing stiffness of sun wheel,planetary wheel and internal ring gear when crack exists in each pair in meshing is calculated and the effects of crack depth and angle on time-varying meshing stiffness are explored.The research provides theoretical help for the mastery of planetary gear fault mechanism.关键词：Planetary gear;Meshing stiffness;Crack;Fault excitation
- 4
- |
- 211
- |
- 1
发布时间：2022-10-20 - 摘要：The study of the lower limb movement model of the human body is one of the core contents of the exoskeleton robot driving and control system. Aiming at the shortcomings of complicated fitting process,discontinuity after high order derivation of the model and so on in the fitting process of ankle joint motion model by using piecewise function,the Fourier series method is used to establish the model of the horizontal movement of the ankle joint in the sagittal plane,and the motion model of the ankle joint in the sagittal plane is established by using the polynomial fitting process,it has a simple,accurate,non-impact characteristics by the ankle articulation model obtained by the method,and the model is continuity and the conductivity. Finally,the model can be used to demonstrate the characteristics of the ankle movement in healthy people,at the same time,motion simulation is performed by ADAMAS to verify the correctness of the ankle driver used in exoskeleton robots. The study of the lower limb ankle movement model of the human body provides an important theoretical basis for studying the characteristics of the ankle movement in healthy subjects during normal walking,and provides a reference model for the driving and control of the ankle joint of the exoskeleton.关键词：Ankle joint;Impact;Fourier series;Mathematical model;Simulation
- 5
- |
- 210
- |
- 0
发布时间：2022-10-20 - 摘要：In view of the deficiencies of peak factor,pulse factor and kurtosis factor in the monitoring of rolling bearing running condition,a new method to evaluate the variation of vibration performance of rolling bearing is proposed based on the fuzzy-set theory. Firstly,the original data sequence of the rolling bearing vibration is divided into the sample sequences,and then the intrinsic sequence is selected to calculate the standard deviation of each sample sequence and the absolute correlation degree,the gray confidence level and the closeness degree relative to the intrinsic sequence as new sample values. Then a fuzzy similarity matrix made up of these values processed in order of magnitude and by the linear mapping formula is further transformed into a fuzzy equivalence matrix via transitive closure method and the evaluation of the variation of vibration performance of rolling bearing is made by comparing equivalence coefficients in the fuzzy equivalence matrix with the set threshold（ λ = 0. 5）. Finally,the feasibility and correctness of the proposed method are verified by simulation data and experimental data.关键词：Fuzzy-set theory;Matrix;Performance variation;Evaluation
- 3
- |
- 111
- |
- 5
发布时间：2022-10-20 - 摘要：The copper-based powder metallurgy friction pairs are widely used in hydro-viscous drive. In order to research the frictional characteristics of friction pairs,the frictional coefficient under different working conditions is tested by using MM-Ⅲ friction and wear performance tester. The influences of relative rotational speed,contact pressure and temperature on frictional coefficient are analyzed. The results show that the frictional coefficient changing with relative rotational speed is similar to the Stribeck curve,which drops sharply first and then rises slowly. With the increase of the contact pressure,the viscous shear effect of oil film become lower,and the contact frictional coefficient gradually decreases. In addition,temperature has a small effect on contact frictional coefficient. Therefore,using MM-Ⅲ friction and wear performance tester,the variation of frictional coefficient of copper-based powder metallurgy friction pairs with relative rotational speed,contact pressure and temperature can be obtained,which provides a theoretical basis for the study on mixed friction torque model and speed regulation stability of hydro-viscous drive.关键词：Hydro-viscous drive;Friction pair;Copper-based powder metallurgy;Frictional coefficient
- 5
- |
- 66
- |
- 1
发布时间：2022-10-20 - 摘要：To eliminate the gear backlash,a new inclined double-roller enveloping hourglass worm drive is proposed. The meshing performance is analyzed based on the meshing geometry of inclined double-roller enveloping hourglass worm drive. The physical prototype of inclined double-roller enveloping hourglass worm drive is machined. The transmission performance test of this prototype is carried out on the magnetic powder loading mechanical transmission performance test-bed. The research shows that the inclined double-roller enveloping hourglass worm drive has good meshing performance. The transmission efficiency of the test prototype is between 70. 5% 75. 8%,the average oil temperature is below 50 ℃,the noise is between 70 100 d B,the oil is relatively low and the temperature rise is relatively small.关键词：Hourglass worm gear drive;Meshing performance analysis;Machining;Performance testing
- 4
- |
- 52
- |
- 0
发布时间：2022-10-20 - 摘要：Based on the analysis of the kinematic characteristics of the six-link double-crank slider mechanism of the stamping machine,the structural parameters analysis and optimization design of the six-link double-crank slider mechanism are carried out. Firstly,the kinematics of the six-link double-crank slider mechanism is deduced,and the function expression of each structural parameter is obtained. Secondly,based on the proposed optimization design mathematical model and MATLAB software,the optimization design,kinematics simulation analysis and kinematic characteristics of the six-link double crank slider mechanism are carried out. The results show that the optimization design of the six-link double-crank slider mechanism is of great significance to improve the kinematic characteristics of the stamping machine.关键词：Stamping machine;Double-crank slider mechanism;Kinematics;Structural parameter analysis
- 4
- |
- 313
- |
- 2
发布时间：2022-10-20 - 摘要：Large gear ring forming grinding is the key technology to ensure the quality of ring gear processing. Forming grinding will produce grinding force and a lot of heat,causing grinding deformation. With the help of the engineering software Hypermesh,Matlab and ANSYS,based on the grinding contact area model,the grinding force model and the grinding and moving heat source theory,the simulation process of deformation prediction under the action of gear ring grinding is analyzed. Taking the large gear ring as an example,the grinding area,the grinding force and the heat flow rate are calculated,and the finite element model of the forming grinding of the gear ring is established. The numerical simulation of the grinding field and the deformation field of the gear ring are obtained. The prediction of temperature field and deformation of gear ring forming grinding process has certain guiding significance to improve the machining precision of gear ring forming.关键词：Gear ring;Forming grinding simulation;Finite element analysis;Temperature field;Deformation prediction
- 5
- |
- 105
- |
- 0
发布时间：2022-10-20 - 摘要：A domestic hydraulic pump drive shaft fracture occurred during the experimental verification.The analysis of working conditions,strength safety factor,finite element analysis of work stress,macro fracture inspection,micro topography,microstructure,chemical composition,material hardness of the drive shaft show that the reason for the failure is that the fillet design at the stepped shaft is too small and the heat treatment does not meet the requirements. The design and process optimization route are given,the foundation for improving the service of the drive shaft is laied.关键词：Drive shaft;Fatigue fracture;Failure analysis
- 10
- |
- 142
- |
- 0
发布时间：2022-10-20 - 摘要：The lightly loaded or unloaded gears rattle in vehicle transmission systems is an unsolved issue for vehicle manufacturers. Rattle noises affect customer perception of vehicle quality. Rattle is an unwanted byproduct of clearances and is affected by design of the torsional system,including clutch spring,hysteresis and flywheel inertias and so on. By using a generic torsional drivetrain model for loaded gear rattle analysis,then,the nonlinear responses of the rattling gear is examined. The rattle of the 1 st gear set and 5 th gear set are considered while 2 nd gear is meshed and driven. The accelerations of the 5 th gear set are shown to be more severe under the same excitation condition and thus found to be a larger contributor to the rattle noise. The system is simulated by using a frequency sweep with engine excitation derived from measured data and then peak responses is examined.关键词：Rattle;Gear;Backlash;Loaded;Response
- 2
- |
- 42
- |
- 0
发布时间：2022-10-20 - 摘要：Based on shot-peening hardness tests performed on carburized gear steel,the hardness effectiveness of shot-peening on tooth flank and root is studied,it is aimed to find out the factors and parameters which are related to surface roughness in different shot-peening process parameters,so that rational parameter combination of enhanced shot-peening can be available to provide guidance to enhanced shot-peening on other parts.关键词：Gear;Enhanced shot-peening;Surface roughness
- 3
- |
- 261
- |
- 2
发布时间：2022-10-20 - 摘要：Taking the electron beam welding process as an example,the tooth profile analysis of the split type herringbone gear is carried out after the deformation of the diameter direction. Finally,the problem of the machining of the herringbone gear without the retreating slot is solved. Through the relation of tooth involute,base circle,radius of curvature,pressure angle and helix angle,the change law of tooth profile and spiral line in the condition of gear diameter deformation is studied,and the influence of the change of diameter on pressure angle,spiral angle and the second influence of the change of spiral angle on the tooth shape are analyzed. The formula for calculating deformation is derived,and the composite deformation amount and the composite deformation and tooth helical line deformation amount of the tooth profile due to change of diameter are calculated,the basis for the reverse compensation of the grinding teeth before welding is provided. Finally,the above analysis is verified by an example,and the calculation method is not limited to the electron beam welding process.关键词：Herringbone gear;No tool withdrawal groove;Welding deformation;Reverse compensation
- 4
- |
- 53
- |
- 0
发布时间：2022-10-20 - 摘要：Unlike the normal recurrence quantification analysis（ RQA） which pay attention to the distribution of different kinds of lines such as diagonal lines,vertical lines and horizontal lines,a new perspective to study recurrence plot（ RP） is developed and the local detail spectrum（ LDS） will be proposed as one new RQA measure. This method pay more attention to the local details of the recurrence plot. The application of LDS in gear fault signal is studied in detail. The experiment proved the better performance of LDS in the field of gear fault diagnosis.关键词：Recurrence plot;Local detail spectrum;Recurrence quantification analysis;Gear fault recognition
- 4
- |
- 54
- |
- 0
发布时间：2022-10-20 - 摘要：In Variational Mode Decomposition（ VMD）,k belongs to the custom variable,the decomposition result will be different with the change of k,k directly affects the accuracy of the result,which too large or too small will affect the results. Basis on the question above,a method of determining k by kurtosis is proposed. Selecting an integer value of k between 2 and n,every k kurtosis of the maximum correlation coefficient is calculated,and the variation curve of kurtosis is plotted. If the kurtosis of the curve has no peak and monotonically increases,calculating the kurtosis of k is n+1,repeat the steps above. The maximum kurtosis is used as the criterion of optimization,when the kurtosis is maximum,the k is the best. The feasibility of the method is verified by the actual fault signal,a new thinking of the research for VMD is proposed.关键词：Variational mode decomposition;Decomposition layer;Kurtosis;Fault diagnosis
- 3
- |
- 545
- |
- 11
发布时间：2022-10-20 - 摘要：The tire loaders produced by a certain unit are found abnormal noise when they are tested in the factory. Through the contrast,noise analysis and calculation of noise with and without abnormal sound loaders at different speeds,the cause of abnormal noise is detected,and the diagnosis opinions and suggestions are put forward so that the problems can be solved.关键词：Tire loader;Noise;Spectrum analysis;Fault diagnosis
- 4
- |
- 61
- |
- 0
发布时间：2022-10-20 - 摘要：Aiming at the defects of frequency derangement and overlap in dual-tree complex wavelet packet transform,an improved decomposition algorithm of dual-tree complex wavelet packet transform is proposed. The defect of frequency derangement is eliminated by exchanging the order of sub-nodes originated from high frequency band,and the defect of frequency overlap is overcome by designing the filter of Chebyshev which can eliminate respectively the frequencies outside the pass bands of low frequency and high frequency sub-band. A approach for gearbox fault diagnosis based on the improved dual-tree complex wavelet packet transform and spectral kurtosis is presented,vibration signals of gearbox are decomposed into various frequency band signals,the spectral kurtosis is computed to determine the parameters of band pass filter and got the optimal frequency band. The rotation frequency of fault gear is recognized according to the Hilbert envelope demodulation of the optimal frequency band. The experimental results show that the weak fault feature of gearbox submerged in strong interference can be effectively extracted,and the feasibility and effectiveness of this method are verified.关键词：Dual-tree complex wavelet packet transform;Frequency band derangement;Frequency band overlap;Spectral Kurtosis;Fault diagnosis
- 2
- |
- 186
- |
- 5
发布时间：2022-10-20 - 摘要：In view of the multi-component coupling modulation characteristics of complex fault signals and the envelope error phenomenon of the local average decomposition method,an LMD method based on rational sub-interval Hermite interpolation is proposed. Through calculating the optimal parameter interval,the optimal parameter between the cells and the parameter in the optimal parameter interval is selected to adjust the shape of the interpolation spline so that the interpolation spline is infinitely close to the target to be interpolated,thereby improving the fitting precision and accuracy of the envelope curve. The comparison of simulation data is used to verify the approximation ability and high fitting accuracy of the rational Hermite interpolation LMD method. The method is applied to the diagnosis of compound fault signals of gear and rolling bearing,and the high fitting accuracy of the method is proved again. The accurate diagnosis of compound fault signal is realized.关键词：Gear;Rolling bearing;Compound failure;Three times Hermite interpolation method;Rational Hermite interpolation method;LMD
- 3
- |
- 124
- |
- 3
发布时间：2022-10-20 - 摘要：The laser hardening process is carried out on the tooth surface of 40 Cr rack with module of 2. 5 in high precision linear guide by utilizing a 3 k W diode laser. The single beam laser and dual beam laser hardening process are researched separately. The results show that,when using the single beam laser,the reflected energy have little effect on the microhardness of tooth surface,but the hardened surface will be tempered by the heat conducted from the other side. Compared with the single beam laser,the dual beam laser has many advantages such as lower laser power,more efficiency and more uniform distribution of microhardness.
- 5
- |
- 88
- |
- 1
发布时间：2022-10-20 - 摘要：While gearbox in power plant generator set often work in the environment of high speed,high load and poor lubrication,it is of great significance to study the effective monitor and fault diagnosis of working condition. As to nonstationary feature of fault signal in gearbox,the fault diagnosis method based on wavelet packet decomposition（ WPD） and BP neural network is presented. The measured fault signal is decomposed by the wavelet packet to obtain the energy feature information as the input vector,and the BP neural network is used as the classifier to identify and diagnose it. Through analysis of gearbox under four types of normal condition,tooth surface wear,missing teeth and compound fault,show that the fault diagnosis method can distinguish the fault type in gearbox.关键词：Generator unit;Fault diagnosis;Wavelet packet decomposition;BP neural network
- 4
- |
- 206
- |
- 14
发布时间：2022-10-20 - 摘要：In view of the similarity between transient components extraction from mechanical vibration signals and the significant speech information detection from noisy environment,a gear crack fault feature extraction method based on auditory attention mechanism is proposed. The saliency map calculation model is introduced and improved combined with the characteristic of fault information. By frequency band division and processing,multiscale Gauss filtering,saliency calculation and integration,the transient impact components in fault signals are finally represented by auditory saliency maps. The effectiveness of the proposed method is verified by experiments with simulation and measured signals of gear crack fault.关键词：Feature extraction;Fault diagnosis;Gear crack;Auditory attention;Saliency map
- 2
- |
- 58
- |
- 1
发布时间：2022-10-20 - 摘要：The test bench mainly for the dynamic performance of the synchronous clutch engagement in the BPRT system is designed. The test bench use motor speed control,PLC digital control and fuel injection forced lubrication to adjust it. The PLC module is used to speed regulating control for the frequency conversion motor according to the collected speed and position signal,and real-time monitoring the test bench through the human machine interface. The test bench is simple structure,easy to operate and wide range of speed. According to the experimental data and the meshing dynamic principle of the synchronous clutch,the test bench can better meet the performance test of synchronous clutch at different speeds. It is of great engineering significance to the design and manufacture of synchronous clutch.关键词：Synchronous clutch;Test bench;PLC control;Lubrication
- 6
- |
- 82
- |
- 0
发布时间：2022-10-20
- Technical support is provided by Beijing Founder electronics co., LTD 豫ICP备05013835号-5
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0