最新刊期
期 12 ， 2018
- 摘要：Based on the extended finite element method（ XFEM） and linear elastic fracture mechanics theory,two-dimensional crack propagation calculation program is developed independently with Fortran language,and the accuracy of program calculation is verified. On this basis,the simulation study on the effect of centrifugal force,the initial crack,rim thickness coefficient（ backup ratio） on gear tooth root two-dimensional crack propagation is carried out. The result shows that,the initial tooth root crack location has a great influence on the gear tooth root crack propagation,and the closer of the initial crack position to the center of the tooth groove is,the more likely it is that the rim fracture will occur（ crack propagation along radial）. The rim thickness has a great influence on the gear tooth root crack propagation,and the smaller the backup ratio is,the larger range of the initial crack location is that the rim fracture will occur. The centrifugal force has a great influence on the gear tooth root crack propagation,the larger the centrifugal force is,the more likely the rim fracture will occur,and the larger the initial crack location range of the rim fracture will occur at the same time. This study result has a certain theoretical significance and engineering application value to improve the reliability and ultra-safety of gears in high-speed working conditions.关键词：XFEM;High-speed gear;Centrifugal force;Crack propagation
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发布时间：2022-10-20 - 摘要：In order to study the influence of tooth surface microstructure on gear motion stability,the fractal theory is introduced to realize the simulation of the shape of the cylindrical straight gear tooth surface through the characteristic data of the real tooth surface. With the help of W-M function,M-B fractal contact model and Hertz contact formula,the stiffness and damped mathematical model considering the uneven surface of gear surface is established. The influence of different machining methods on the normal contact stiffness and damping of the tooth surface is analyzed,MATLAB and ADAMS are used to study the influence of normal contact stiffness and damping of tooth surface on the vibration characteristics of gear meshing. The results show that the microstructure of tooth surface affects the stability of gear motion. The machining method affects the meshing stiffness and damping of gears. Compared with grinding and milling,the normal contact damping of electrochemical finishing method is more larger,the method is more effective to reduce the vibration of gears and improve the stability of gear.关键词：Microstructure;Fractal theory;Contact damping;Adams;Matlab;Stability of motion
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发布时间：2022-10-20 - 摘要：The dynamic characteristics of the front end accessory drive（ FEAD） system of automobile engine can affect the noise,vibration and harshness,and the safety,comfort of automobile directly. A mathematical model of nonlinear rotational vibration of FEAD system with an overrunning alternator pulley（ OAP） is established. The influence of OAP on FEAD system is analyzed,and the influence of OAP stiffness on the angle fluctuation of tension pulley and B1 and B3 is gotten. The research can provide some essential theoretical basis and practice guidance for the optimization of FEAD system and OAP.关键词：Front end accessory drive;Overrunning alternator pulley;Automobile engine;Dynamics analysis;Nonlinear vibration
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发布时间：2022-10-20 - 摘要：Based on the actual structure and work conditions of wet multi-disc clutch,a finite element analysis model of wet clutch is established by using Abaqus. The Mises stress field of friction pairs in wet clutch is analyzed by the direct thermal structure coupling method,and the influence of the applied load way of piston in wet clutch on the Mises stress field of friction pairs is studied. The results show that the applied load way has an important effect on the maximum stress distribution and axial stress transfer velocity of separator plate. And the bandwidth of high stress area and the velocity of stress transfer along axial direction under uniform load are larger than those in partial load. In addition,the maximum stress and radial stress gradient of separator plate under the partial load way is greater than that under uniform load way.关键词：Wet clutch;Stress field;Applied load way;Thermal structure coupling
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发布时间：2022-10-20 - 摘要：Based on the theory of envelopes for the single parameter family of surfaces,the globoidal indexing cams mechanism are calculated and analyzed. The unifi mathematical expressions of the contour surface geometry for globoidal cams with cylindrical,conical,and hyperbolic meshing turret-rollers are derived by homogeneous coordinate transformation. The correctness of the method and model is verified by an example. A foundation for the derivation of the expression of pressure angle and main curvature is laid,and a reference for computer aided design and manufacture of spatial cams is provided.关键词：Globoidal indexing cam;Theory of envelope;Profile equation;Generalized expression
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发布时间：2022-10-20 - 摘要：According to the forming process principle,the influence of the tooth profile modification,helix modification and tooth profile deviation,helix deviation and eccentricity tolerance of radial run-out of the involute helical gear on tooth profile shape is analyzed. The curve equations of the involute transverse tooth profile are derived step by step. By using the software,the curve equation of deviation is fitted,and the theoretical curve is replaced by the deviation curve. Then,the actual tooth profile model and solid model including modification and deviation of gear are generated.关键词：Involute tooth profile;Modification;Deviation analysis;Forming process
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发布时间：2022-10-20 - 摘要：Based on the additional stiffness caused by the crack,the non-linear Hertz contact of the rolling bearing,and the Varying compliance（ VC） vibration caused by the variation of the bearing stiffness of the rolling bearing,a double-span rotor model with transverse crack under rolling bearing support is established by Lagrange equation. Considering the problems of eccentricity and rubbing,the nonlinear dynamics behaviors of the system caused by singular and coupled faults are numerically simulated by the variable step Runge-Kutta method. The effects of crack propagation,crack angle and rolling bearing radial clearance on the system response are analyzed based on the bifurcation diagram,axial locus diagram,Poincare section diagram and 3 D spectrum. The results show that when a single fault occurs,a large range of chaotic motions occur in the supercritical rotational speed region. When the coupling fault occurs,the response of the system is affected by the combination of unbalanced rotation and VC vibration in the subcritical rotational speed region and enters the quasi-periodic,the frequency division begins after exceeding the critical speed,it shows strong nonlinear characteristic. When the crack is shallow,the influence on the system response is not obvious. When the crack is deeper,the response of the system changes obviously in the high revolving speed area. The crack angle has a great influence on the chaos motion. There is no essential effect on the periodic movement,the system response is sensitive to the change of the rolling bearing clearance. The research results have certain guiding significance for controlling and predicting the failure of rotating machinery.关键词：Rotor-rolling bearing system;Nonlinear response;Runge-Kutta method;Simpson method;Crack;Rub-impact
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发布时间：2022-10-20 - 摘要：A tooth profile design approach for harmonic drive（ HD） with nice meshing qualities is proposed. The criteria for tip interference judge,interference zone determination and sample points generation,which will achieve the tooth profile design well are proposed in this method. When one HD tooth profile is given,tooth profile parameters of the other conjugate tooth are sufficiently determined by this method,which can remove tip interference but guarantee the meshing performance on the conjugate zone without repeated simulation,interference check and revise. Taking the design of a pair of tooth profiles of HD as example,the tooth profile parameter of rigid spline is designed under the given tooth profile of flexspline. Analysis of fitting error and backlash demonstrates that the designed tooth profile of the rigid spline is very close to the theoretical conjugate curve,the backlash distribution is ideal,the contact ratio and maximum engaging depth are guaranteed,which proves that the tooth profile parameter design method is effective and can guarantee the meshing performance.关键词：Harmonic drive;Meshing performance;Tooth profile parameter;Tooth tip interference
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发布时间：2022-10-20 - 摘要：The non-orthogonal bevel gear is the key component of a four-cylinder double-acting Stirling engine variable incline angle swashplate drive device,which can be used to support the torque of the inclined plate inclination in the angle adjustment of the inclined plate. In order to ensure the reliable and effective operation of the engine,the design of bevel gear and the analysis of fine strength are necessary. Based on this,in view of the high power four-cylinder double-acting Stirling swashplate engine,based on the variable angle of inclined plate transmission device layout requirements,the parameter design research of a Stirling engine nonorthogonal bevel gear transmission system is conducted,three-dimensional model of fine bevel gear contact strength analysis is established. Secondly,simulation analysis is carried out by using the finite element analysis software Workbench to verify the performance of the non-orthogonal bevel gear transmission system. On this basis,the influence of geometrical parameters on meshing properties of bevel gears is discussed. The results show that the maximum shape variables and the maximum stress of the gear are decreased with the increase of the tooth number in a certain range. This conclusion will provide certain theoretical basis for design and dynamic analysis for four-cylinder double-acting Stirling engine variable angle of inclined plate drive system optimization and performance improvement.关键词：Finite element analysis;Non-orthogonal;Bevel gear;Stirling engine
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发布时间：2022-10-20 - 摘要：Based on higher order contact meshing theory of conjugate curvature,a three-dimensional model of the new type double helical tooth synchronous belt and the belt drive are established. The nonlinear finite element analysis software is used to analyze the stress and deformation of the new type double helical tooth synchronous belt and the pulley. Through the analysis,the change law of the helix angle,backlash,and pulley structural parameters on the stress and deformation of belt tooth and strength layers is studied,and the structural parameters of the new type double helical tooth synchronous belt with high integrated load carrying capacity are optimized. During laboratory bench fatigue life test,the new type double helical tooth synchronous belt has longer fatigue life than the same tooth profile with straight tooth synchronous belt.关键词：New double helical tooth synchronous belt;Pulley;Helix angle;Backlash;Pulley groove width
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发布时间：2022-10-20 - 摘要：Aiming at the problem that the numerical atlas method can’t be used to synthesize the finitely separated positions design requirements for the planar four-bar mechanism,based on the complex function least square method,a method for realizing the feature extraction of finitely separated positions discrete points is proposed by using the Fourier series approximation fitting finitely separated position. The relationship of feature parameters between the finitely separated positions and their transformations,including translation,rotation,and scaling is found. Combining with numerical atlas method,the finitely separated positions design requirements path generation of the planar four-bar mechanism is realized. Examples are presented to illustrate the applicability and effectiveness of the proposed method.关键词：Feature extraction;Planar four-bar;Fourier series;Normalization
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发布时间：2022-10-20 - 摘要：In order to obtain the best overall performance of cycloid profile,a multi-objective optimal design method of cycloid gear profile modification is presented. The cycloidal gear tooth profile equation and modification theory are introduced. The contact force of the cycloidal gear tooth surface is calculated. A multiobjective optimization model with considering the meshing characteristics of the cycloidal gear and the contact force of the tooth surface is established. The NSGA-Ⅱ algorithm is used to solve the multi-objective optimal problem,and compared with the optimal method of the least contact force of the tooth surface of the cycloidal gear. The results indicate that the fitting degree of this method and the angle modification tooth profile is improved by 3. 99 times,compared with the optimization method with the highest degree of fitting to the angle modification tooth profile,the contact force of the tooth surface of the method is reduced by 4. 98%. The multi-objective synthesis optimum of cycloid is achieved,and the feasibility and superiority of this method is proved.关键词：RV-550E reducer;Profile modification;NSGA-Ⅱ;Multi-objective
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发布时间：2022-10-20 - 摘要：Based on the gear meshing principle and the meshing theoretical mathematical model of torus enveloping circular arc worm pair（ ZC1）,the changing trend of momentary contact line of worm pair is obtained. The influence of its basic parameters on the induced curvature,lubrication angle and instantaneous contact line and the speed of the direction of the angle between the impact are analyzed. Choosing the three parameters of modulus m,displacement coefficient x and lead angle γ,which have a greater impact on the transmission quality as a design variable to establish optimization model. By using the particle swarm optimization,the efficiency of circular torus envelope arc cylindrical worm gear is optimized. By using the KISSsoft and comparing the results before and after optimization,the simulation result shows that the optimized efficiency of torus worm gear pair with torus envelope envelopment is improved to a certain extent,which is of great significance to the parameter design of torus enveloping circular worm pairs.关键词：Torus envelope arc cylindrical worm;Instantaneous contact line;Transmission efficiency;Particle swarm optimization
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发布时间：2022-10-20 - 摘要：In order to design a new spatial truss deployable mechanism with high folding rate and analyze its unfolding motion,2-DOF modularized deployable mechanism unit constituted from two rectangular pyramids arranged symmetrically is proposed. Firstly,modularized principle of truss deployable mechanism is explained.Secondly,according to folding conditions during the motion,the geometric coordination equations are derived.Finally,the deployable mechanism is simplified to a planar mechanism based on its kinematic characteristic,and its freedom of degree is computed and kinematics equations are established based on closed loop vector.关键词：Spatial truss deployable mechanism;Modularized deployable unit;Geometric equation;Kinematic analysis
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发布时间：2022-10-20 - 摘要：Based on the basic profile of the tool,according to the tooth profile normal method to obtain the flexible gear tooth profile,then the conjugated rigid wheel profile is solved by the envelope theory. Using the data processing ability and graphics display function of the Matlab software,the parameters and shape of the flexion wheel tooth profile is displayed by programming,and the new tooth profile meshing performance is judged,the theoretical meshing arc length and the number of pairs of tooth meshing at the same time are calculated. The backlash value of every point in the flexible gear profile to rigid wheel tooth profile is solved,then the minimum backlash value is found out and rule analysis is carried out,the rigid flexible wheel does not engage in meshing interference is verified. The deflection of the gear teeth caused by the flexible wheel deformation is analyzed,and using the method of modifying displacement coefficient to solve the meshing problem caused by the flexible wheel deformation,and the three-dimensional tooth profile of the rigid wheel is designed to avoid meshing interference without changing the parameters of the flexible wheel tooth profile.关键词：Harmonic drive;New tooth profile;Meshing performance;Three-dimensional tooth profile
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发布时间：2022-10-20 - 摘要：A high-speed cam design method is proposed based on the Fourier series and principle of Minimum Gaussian square difference. The design principle for the cam of the Fourier series follower motion law（ referred to as the Fourier series cam） and the construction of its displacement function are analyzed. Taking the flat-bottom centering setting push rod-cam mechanism as an example,the cam profile of the Fourier series cam is designed. A valve train including the cam mechanism is established,the natural vibration modes and motion features of the valve are analyzed to validate the work property of the cam. The results show that the displacement curve of the valve is determined by the profile of the cam within a certain range of rotation speeds.The maximum value of velocity of the valve will increase with the increase of the rotation speed of shaft and the increase of the valve clearance. The acceleration of valve will increase first and then decrease in the rise process and will have a symmetric trend in the return period.关键词：Fourier series;Cam;Natural vibration mode;Performance analysis
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发布时间：2022-10-20 - 摘要：Aiming at the problem that the upper limb rehabilitation robot has secondary damage caused by inertial impact,a new mechanism of a rope traction upper limb rehabilitation robot is designed by using the hybrid mechanism. To ensure the safety and stability of the rehabilitation robot,the static strength analysis and modal analysis of the structure of the upper limb rehabilitative robot is carried out by using ANSYS Workbench.Moreover,the multi-objective genetic algorithm is applied to the lightweight optimization design of the support frame. The result shows that the total mass of support frame after optimization is comparatively 48% less than before. At the same time,the inherent characteristic of the whole frame is obtained,which is prepared for the later control strategy.关键词：Hybrid mechanism;Rope traction;Rehabilitation robot;Finite element analysis
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发布时间：2022-10-20 - 摘要：The stress in bottom of flexspline will increase rapidly with ratio of length to diameter of the harmonic gear. In order to decrease the stress in bottom of very short cup flexspline,the solid finite element models of parametric cup-shaped and hat-shaped flexspline are established,and the maximum stress and its distribution rule under the assembly state and load condition are calculated respectively. The effects of the geometric parameters such as the ratio of length to diameter,width of the diaphragm and fillet radius on the maximum assembly stress and load stress in the bottom of the flexspline are compared and calculated. The study shows that the very short cup-shaped flexspline is capable of small loading transmission,while the hat-shaped flexspline is suitable for large loading transmission. And much lower stress will be produced in hat-shaped flexspline by increasing width of diaphragm.关键词：Harmonic gear;Cup-shaped flexspline;Hat-shaped flexspline;Very short cup;Assembly stress;Finite element
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发布时间：2022-10-20 - 摘要：The start-stop process generally exists in rotating machinery,and the speed change of the process has a great influence on the dynamic performance of rolling bearing,while the study on the dynamic characteristics of rolling bearing in the start-stop process is relatively lack. Taking cylindrical roller bearing NU306 as investigation object,a three-dimensional dynamic FEM for nonlinear contact cylindrical roller bearing is established. Based on explicit dynamics finite element method,the dynamic simulations of cylindrical roller bearing in the start-stop process for different angular acceleration and different radial load conditions are carried out. The influence of angular acceleration and radial load on its dynamic characteristics in the start-stop process are studied,which are the angular velocity of cage,and the centroid displacement of inner ring and the contact force between rollers and cage,and the experimental verification is carried out. The study results show that the increase of the inner ring angular acceleration will increase the slip of rolling bearing in the start-stop process,and the increase of radial force will reduce the slip of rolling bearing in the start-stop process,and in the start-stop process,the greater the angular acceleration and radial force,the greater the centroid displacement of inner ring and contact force between rollers and cage. The simulation results are in good agreement with the experimental results,and the validity of the finite element model is verified.关键词：Cylindrical roller bearing;FEM;Start-stop process;Dynamic characteristic;Explict dynamics
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发布时间：2022-10-20 - 摘要：Taking the Q1-205 type double-rectangular cavity hydrostatic thrust bearing as study object,the method combining theoretical analysis,dynamic simulation and experimental testing is used,aiming at the variation of oil film thickness under six inlet velocity and three working speed conditions,the velocity field,vorticity and pressure field are analyzed. Though the dynamic mesh technique,the relationship curves between the film thickness and the flow rate,vorticity and pressure of the film under different operating conditions are obtained. Which revealed the dynamic change rule of film performance. The results show that the low speed regions and high vorticity regions in the oil cavity are located at the edge seal of the countercurrent side,and the phenomenon increases with the decrease of film thickness. In the wake of the inlet velocity and pressure of oil cavity raise the pressure in the cavity reduces with the increase of working speed due to the serious pressure loss.关键词：Double-rectangular cavity hydrostatic thrust bearing;Velocity field;Dynamic mesh;Vorticity;Pressure field
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发布时间：2022-10-20 - 摘要：Aiming at the design problem of high lifespan and high bearing capacity of flexspline,taking the fillets and generator as the research object,parametric model are performed in ANSYS by response surface method and the central composite design method is used for sampling. The stiffness and stress at three points are selected as observation objects and the influence law of each fillet parameter are obtained. The analysis results show that increasing the size of each fillet can effectively reduce the stress concentration in various places and increase the stiffness. Based on the comprehensive consideration of the stress and stiffness,the optimum structural parameters are selected. In order to increase the stiffness and improve the bearing capacity of the flexspline,the drafting feature is designed at the bottom of the flexspline,and the parameter is analyzed and optimized. The short axis radial deformation of the non-standard elliptical cam generator can be increased to reduce the stress.关键词：Flexspline;FEM;Structure design;Optimization design;Stiffness;Drafting feature;Non-standard elliptical cam
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发布时间：2022-10-20 - 摘要：According to the basic theory of heat transfer,gear meshing and tribology,using thermal-structure coupling theory and finite element whole simulation analysis method,the three-dimensional finite element model for a pair of spiral bevel gear in the use of aeronautic is established. The single structure load analysis and the whole thermal-structure coupling analysis are carried out for a group of spiral bevel gear,and the results are compared and analyzed. Finally,the results are comparatively analyzed and verified by using the KISSsoft mechanical transmission design and analysis software. The results show that the maximum contact stress occurs on the meshing surface near the top of tooth,approximately presenting oval-shaped distribution. The maximum contact stress of thermal-structure coupling analysis of gear teeth relative to static contact stress and KISSsoft contact stress have respectively increased 5. 3% and 7. 45% due to the influence of bulk temperature fields,which illustrates the results of the finite element analysis and the results of the KISSsoft analysis are consistency,and then a theoretical basis for the structure optimization and gear modification of the spiral bevel gear pair can be provided.关键词：Spiral bevel gear;Thermal-structure coupling;Temperature field;Finite element analysis;KISSsoft
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发布时间：2022-10-20 - 摘要：In order to analyze fault-switching of two input differential mechanism under conditions of acceleration and deceleration,the rigid-body dynamics formulae of planet differential mechanism are deduced theoretically when two inputs worked together and only one input worked. The laws of the formulae are summarized.Fault switching procedures and mode analyses are analyzed in conditions of one channel（ master-alternate） and two channels（ master-master）. The analysis got the conclusion as follows. When there is only friction load at the output of the differential mechanism,it is deduced that direction of friction load is always opposite to the direction of velocity. This characteristic that friction load is resisting force but not dynamic force whether or not the switchover path is switched over. The characteristic contributes to deceleration braking of faulty channel. Four fault-switching schemes are analyzed. The first scheme is always single channel module. The accelerating capacity of one way is better than two ways. The switching procedure of the first scheme is simple. The switching time of the first scheme is short. Thus the first scheme is recommended.关键词：Planet differential mechanism;Rigid-body dynamics;Fault switching;Mode analysis
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发布时间：2022-10-20 - 摘要：Due to the large size and weight of large wind turbine gearbox,its statics characteristic and gear contact characteristic are different under different supporting method. Taking the large wind turbine gearbox as research object,based on the performance parameters under the ultimate load,the influence of the different supporting method on wind turbine gearbox is researched by using the finite element method（ FEM）,and the contrastive analysis of calculation results is carried out. The results show that the stress and deformation of the box are much smaller if there is a foot supporting at the bottom of the gear box than that if there is no foot supporting,the gear contact stress of the gearbox changes little,and the meshing misalignment of the first-stage gear transmission varies greatly. The research results provide a data basis for the optimal design of large wind turbine gearbox.关键词：Meshing misalignment;Support method;Wind turbine gearbox;Statics analysis
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发布时间：2022-10-20 - 摘要：In order to study the transmission performance and performance comparison of two kinds of structure squirrel-cage and compound solid type of drum-type adjustable speed permanent magnetic asynchronous couplers,the aim is to improve the transmission efficiency and power of permanent magnetic asynchronous couplers in different applications. Firstly,through finite element calculation,the effects of squirrel cage rotor slot parameters on transmission torque and starting torque of squirrel cage permanent magnetic asynchronous couplers and the effects of copper thickness on transmission torque and efficiency of compound solid type permanent magnetic asynchronous couplers are respectively discussed. Then,contrastive analyses of mechanical characteristics,temperature and adjustable speed characteristics for two magnetic coupling with the same structure parameters are carried out. The results indicate that the squirrel-cage permanent magnetic asynchronous couplers can provide higher output torque at high speed and can operate in higher output speed and transmit higher output power.关键词：Magnetic coupler;Finite element;Adjustable speed performance;Temperature field;Transmission performance
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发布时间：2022-10-20 - 摘要：Aiming at the test detection of the performance and accuracy of RV reducer,a comprehensive performance test bench,which can complete the detection of transmission accuracy,torsional stiffness,backlash,friction torque and no-load start stop torque is developed. The test bench based on optical,mechanical,electrical and other advanced measurement technology,the grating high frequency subdivision,precision assembly and error compensation and other proprietary technology are proposed,the 1″high-precision measurement and multi-performance integrated measurement and the serialization are realized. Through user verification,the bench fully meets the requirements of engineering test.关键词：RV reducer;Test bench;Detection
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发布时间：2022-10-20 - 摘要：In order to achieve integration of shaped-profiles parameterization and size optimization of rotor pair for roots pump. From the common circular arc rotor as a example and the conjugate rotation relationship of two identical rotors,full parameter coordinate equation and its corresponding 3 D model are derived in both cases of circular arc as peak profile or circular arc as valley profile. Then,from pitch circle radius and shape coefficient as two design variables,the minimum wrapping cube space volume of rotor pair as an objective function,the upper limit of the shape coefficient and rounded-value of center distance and the diameter ratio of the rotor and other as constraint functions. The size optimization model is derived,then an instance is operated and its results are analyzed. All results show that the two sets of coordinate equations described for rotor shaped-profiles with circular arc as peak profile or circular arc as valley profile is verified absolutely correct by its corresponding3 D parameter model of single part and assembly rotor parts. Only by the three-order polynomial fitting,the fitting accuracy of the volume utilization coefficient is higher to be met the design requirements. The optimization selecting of rotor size is necessity emphasized by the optimal pitch circular radius of 103 mm and the optimal shape coefficient of 1. 394 4,etc. It is concluded that the full parameter optimization design method can be used for other shape rotor of roots pump.关键词：Roots pump;Circular arc rotor;Shaped-profile parameterization;Volume utilization coefficient;Design optimization
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发布时间：2022-10-20 - 摘要：Taking the front housing of a certain type of planetary gearbox as the research object. At first,by using the LMS modal test system,an impact hammer test on the front housing of gearbox is performed,which is hung with rubber bands to simulate the free boundary conditions. By processing the collected data with LMS Test. Lab software,the first 8 order natural frequencies and damping ratios of the front housing of gearbox are identified. The modal results are verified according to the modal confidence criterion,it turns out that the experimental modal parameters identification results are reliable. Since the specific materials and grades of the cabinet are unknown,the accurate finite element model can’t be established. Combining numerical simulation with experimentation,the experimental parameter set is established by using the multi-factor orthogonal test method,and finally the reliable material property parameters of the gearbox are obtained.关键词：Modal test;Parameter identification;Numerical simulation;Orthogonal test
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发布时间：2022-10-20 - 摘要：The helix line modification of pinion is determined by the analysis of the deformation of the pinion,through the mathematical modeling of gear dynamics,a theoretical basis for transmission error is provided.The gear modification of output gear of a 2 MW wind turbine gearbox is carried out. The tooth profile modification of gear pair is carried out by using the KISSsoft software. The model of a 2 MW wind turbine gearbox is built by MASTA software. The pinion helix line modification is designed according to the deformation of pinion and the related formula. According to the simulation analysis of wind power gearbox,the load distribution and transmission error of the gear before and after modification are compared. According to the testing of a 2 MW wind turbine gearbox,the vibration speed of the output end and the gear meshing situation under each working condition are researched and analyzed,the rationality of modification is determined.关键词：Gear modification;Gearbox;Dynamics;Simulation analysis;Testing research
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发布时间：2022-10-20 - 摘要：In order to solve the difficulty in fault feature extraction of the planetary gearbox vibration signal,a comprehensive fault diagnosis method based on empirical mode decomposition（ EMD）,singularity value decomposition（ SVD） and probabilistic neural networks（ PNN） is proposed. Firstly,with the EMD method,de-noised vibration signals are decomposed into a finite number of intrinsic mode functions （IMF）. Secondly,some IMF components are selected according to the criterion of correlation coefficient and variance contribution ratio,and singular value sequences regarded as eigenvectors are obtained with the method of SVD. Lastly,the eigenvectors serve as import of PNN so that faults of the planetary gearbox are recognized. Experiments are conducted on the planetary gearbox fault diagnosis test-bed and comparison is carried out with eigenvectors made of energy entropy,which fully validates the effectiveness of the proposed methodology.关键词：Planetary gearbox;Empirical mode decomposition;Singularity value decomposition;Probablistic neural networks;Fault diagnosis
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发布时间：2022-10-20 - 摘要：For the problem that the gear fault feature is difficult to extract in actual working condition,a fault feature extraction method based on vibration signal time-frequency image is proposed,which is based on the global texture of the contourlet transform and the local texture of the local binary pattern. Firstly,the vibration signal is transformed into the time-frequency domain by wavelet transform and then the time-frequency gray image is obtained. Then,contourlet transform is performed on the gray image,the low frequency and high frequency subbands are gotten,the low-frequency mean,standard deviation and the high frequency subbands of each layer of the average energy are extracted as part of a feature vector. At the same time,the feature values of the local binary pattern of the time-frequency gray image are extracted and another feature vector is obtained,and the final feature vectors are obtained by the combination of the two feature vectors. Finally,the data of different conditions from a gearbox and rolling bearing are classified and tested by using SVM,the experimental results show the effectiveness of the method,an effective method for the pattern recognition of mechanical equipment is provided.关键词：Contourlet;Local binary pattern;Time-frequency image;SVM;Pattern recognition
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发布时间：2022-10-20 - 摘要：Due to the improper selection of the method,the leakage diagnosis or misdiagnosis usually occurs when the composite fault features in the gearbox are extracted. As a result of noise,there will be the phenomena of mode aliasing after LMD decomposition. In view of this,a hybrid fault diagnosis method of the gearbox based on CPFs-MOMEDA is proposed. First,the original signal is denoised by LMD,and a series of PFs are obtained. And the false component and the residual component are removed by the correlation coefficient method. Then,the definition of multi-point kurtosis is introduced,and the fault feature period is extracted by calculating the multi-point kurtosis spectrum of each layer of PF,and the PF without periodic impact is eliminated. In order to maintain the integrity of the original signal,PFs with the same period are recombined by the combined product function method. Finally,the recombinant signal is denoised by MOMEDA by setting different period intervals to further extract the fault characteristics. And the method is applied to the feature extraction of gearbox composite faults to verify the feasibility.关键词：Composite fault;Local mean deconvolution;Combined product function;Multipoint optimal minimum entropy deconvolution
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发布时间：2022-10-20 -
- 摘要：<正>《机械传动》杂志创刊于1977年（原名齿轮）,由中国机械工业联合会主管,郑州机械研究所有限公司、中国机械工程学会、中国机械通用零部件工业协会齿轮分会共同主办,中国机械工程学会机械传动分会协办。本刊是中文核心期刊,中国科技核心期刊,中国核心学术期刊,中国科学引文数据库和中国学术期刊综合评价数据库统计源期刊,中国期刊网、中国学术期刊（光盘版）、万方数据、维普数据库、超星期刊域出
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发布时间：2022-10-20
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