最新刊期
期 4 ， 2019
- 摘要：According to the principle of differential geometry and the theory of gear meshing， and with CNC milling machine high speed milling machined face gear as the research object， the mathematical model of straight tooth face gear is established. Based on the concept of virtual copying of plunge milling cutter to the gear shaper tool， the cutter position calculation of meshing point in high-speed milling process is carried out. Then through the calculation of straight tooth cylindrical gear milling cutter angle range and spindle feed range， by using the UG post processing， the tool path generation and program is got. With the help of VERICUT software， the high speed milling simulation of face gear is carried out. High speed milling test of face gear and detection of face gear is carried out. And by comparing the experimental results and theoretical tooth surface， it is shown that the maximum error is 0.712 μm. The result indicates that the processing way of high speed milling surface gear is feasible.关键词：High speed milling;Face gear;Plunge milling;Cutter position calculation;Tool path generation
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发布时间：2022-10-03 - 摘要：A novel 3T2R hybrid mechanism that consists of a 3-RRP4RR parallel mechanism and a two degree of freedom rotating mechanism is proposed according to engineering application scene of labelling for the round steel end surfaces of a bundle. A method of combining two Monte Carlo methods is proposed to solve the workspace of the hybrid mechanism. The kinematics model of the hybrid mechanism is established. According to the geometric relationship of the parallel mechanism， the inverse solution equation is obtained，and the constraints of the workspace of the parallel mechanism are determined. The set of points in the workspace of the parallel mechanism is obtained by using Monte Carlo method. The kinematics positive solution of the series mechanism and the kinematics positive solution of the hybrid mechanism are obtained according to the coordinate transformation matrix. The coordinates of the points in the workspace of the parallel mechanism is substituted into the positive solution of the position of the hybrid mechanism， and by using Monte Carlo method， the set of points in the workspace of the hybrid mechanism is obtained.关键词：Hybrid mechanism;Monte Carlo method;Kinematics;Workspace
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发布时间：2022-10-03 - 摘要：In order to solve the problem of wear and scorch caused by the stern bearing in the start-stop phase， a new type of bearing with a combination of spiral cavity and ladder cavity is proposed based on the finite element analysis software Fluent. Firstly， the flow field analysis is used to simulate the pressure of the traditional bearing and composite bearing. Secondly， the water film pressure is integrated to obtain the bearing capacity， and the influence of the rotating speed on the two is analyzed. Finally， the composite bearing based on fluid-solid coupling is analyzed by using ANSYS Workbench. The results show that the composite bearing has a 20%~30% increase in bearing capacity compared with the conventional bearing， and the deformation is mainly concentrated at the end of the liner， which provides effective theoretical guidance for the engineering practice and has a good engineering prospect.关键词：Stern bearing;Spiral cavity;Finite element method;Carrying capacity
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发布时间：2022-10-03 - 摘要：To obtain more accurate dynamics change law for asymmetric involute gear， dynamics model of asymmetric involute gear is established by introducing time-varying stiffness and gear backlash. The time history chart， phase diagram， Poincaré perception map and FFT spectrogram are obtained by Runge-Kutta method， then the dynamics behaviors of gear with time-varying stiffness and changing backlash are analyzed. The research result shows that the average meshing stiffness of asymmetric involute gears is greater than that of symmetrical involute gears， and the asymmetric involute gear has better dynamics performance. And the one-order harmonic component in the varying mesh stiffness has little effect on dynamics performance， but the average mesh stiffness has greater impact. Moreover， the relationship between the average mesh stiffness and dynamics performance are nonlinear. That is， with the increase of the average meshing stiffness， the dynamics characteristics becomes better from worse， but the average meshing stiffness continues to increase and then the dynamic characteristics become inferior， so the optimal value of the average meshing stiffness should be determined according to the actual working conditions. In addition， when the gear backlash adds， the dynamics performance drops， so as to the symmetrical involute gear. The research here provides a great theoretical significance and practical value for expanding the theoretical system of asymmetric involute gear dynamics and improving its transmission performances.关键词：Time-varying stiffness;Gear backlash;Asymmetric involute gear;Dynamics characteristic
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发布时间：2022-10-03 - 摘要：Based on the finite element numerical analysis method， the dynamics equation of herringbone gear transmission system is given and the model of rotor-bearing-gear dynamics system is established. The influence of shear， bending， torsion， axial force， gyroscopic effect and internal damping of rotor shaft are considered in the modeling process， and the influence of time-varying mesh stiffness and transmission error of herringbone gear pair is also considered. The dynamics analysis of high speed gear rotor is also carried out， which is basically consistent with the measured data of the test gearbox.关键词：High speed transmission;Herringbone gear;Dynamic characteristic
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发布时间：2022-10-03 - 摘要：In the noisy environment， the composite fault feature extraction is more difficult. The VMD is widely used in gearbox fault diagnosis， but it is a parametric decomposition method. If K is too large or too small， it will lead to over-decomposition or under-decomposition. The number of layers needs to be determined adaptively， a multi-point kurtosis -VMD （Variational Mode Decomposition） composite fault feature extraction method is proposed. Considering the multi-point kurtosis， the number of impact cycles of multiple faults can be extracted， the number of periodic impacts determines the number K of decomposition layers of the VMD， and after VMD processing， the fault features are further determined by FFT. The proposed adaptive composite fault feature extraction method and Ensemble Empirical Mode Decomposition （EEMD）comparison analysis verify that it can overcome the characteristics of modal aliasing. The effectiveness of this method is further determined by the measured signal processing. The composite fault characteristics such as gear spalling and bearing balls are finally determined.关键词：Multipoint kurtosis;Variational mode decomposition;Composite fault;Feature extraction
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发布时间：2022-10-03 - 摘要：Based on the calculation optimization and spectral characteristics of the transmission error， the gear MDOF vibration model is dexterously simplified to a dual-mass vibration model by utilizing the frequency spectrum characteristics of the system transmission error and the frequency characteristics of the forced vibration under excitation. An analytical solution for gear vibration under the excitation of gear transmission error is obtained. A function between the frequency spectrum of gear quality， stiffness and transmission error and the vibration frequency spectrum of gear is established. The key parameters of vibration evaluation， such as gear vibration amplitude， vibration force of tooth， vibration force on bearing and housing are obtained， and the effects of mass， stiffness and transmission error spectrum on vibration are analyzed， which provides a clear and reliable way to analyze and solve the NVH（Noise， Vibration， Harshness） problem of electric vehicle reducer.关键词：High speed gear;Transmission error;Vibration and noise;Responsive incentive
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发布时间：2022-10-03 - 摘要：As an important component in the automobile drive system，the performance of drive shaft has influence on NVH performance of the whole vehicle. In order to improve the influence of drive shaft on NVH performance，a design scheme to replace the intermediate universal joint of the drive shaft with Birfield CV joint is proposed based on the transmission characteristics analysis of universal joint and Birfield CV joint. The exciting forces at the inter-mediate support of three universal joint for two kinds of the drive shaft are solved and analyzed respectively. Results show that， due to the stable additional bending moment，the Birfield CV joint can reduce the exciting force at the intermediate support as well as the body of the vehicle，thus the NVH performance of the whole vehicle is improved.关键词：Drive shaft;Universal joint;Additional bending moment;Intermediate support;Exciting force
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发布时间：2022-10-03
Theory·Reserach
- 摘要：By an organic combination of the intelligent optimization algorithm and the numerical iteration method， a general algorithm called hybrid artificial bee colony and Newton iteration （HABC-Newton） algorithm for solving the forward positions of parallel mechanism is constructed. The differential evolution （DE） algorithm is incorporated into the artificial bee colony （ABC） algorithm to form a hybrid ABC （HABC） algorithm which can converge quickly to the near optimal solution of the problem. Then the optimal solution is used as initial value and Newton-Шамарский iteration method is employed to find high precision solutions. Taking 4-SPS-CU parallel mechanism kinematics analysis as an example， the forward kinematics analysis method of parallel mechanism based on HABC-Newton algorithm is stated. In order to verify the effectiveness and universality of the algorithm， two numerical examples of forward kinematics such as 4-SPS-CU and 3-RRR coupled parallel mechanisms are given. The results show that the HABC-Newton algorithm can obtain all the high accurate solutions of the parallel mechanism with less computational cost. Furthermore， comparative tests to solve these examples are carried out with HABC-Newton， ABC， DE and particle swarm optimization algorithms， and the numerical experiments indicate that HABC-Newton algorithm has better performance than compared algorithms in terms of the accuracy， robustness and computational efficiency.关键词：Parallel mechanism;Forward position solution;Artificial bee colony algorithm;Differential evolution operator;Newton iteration method
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发布时间：2022-10-03 - 摘要：A new kind of parallel mechanism is proposed， which can realize three mobile one rotation （3T1R）， and it’s a perfectly symmetrical parallel mechanism of the 4-CRU branch， and then its four branched chains are identical in structure. Based on the theory of SOC and the principle for the structure coupling-reducing， structural decoupling design of 4-CRU parallel mechanism is carried out， and a new 2-（CRR）2R type parallel mechanism with lower coupling degree of κ=1 is proposed. And the advantage of it is that the dynamic platform is composed of two chains in parallel， the angle of the mechanism is relatively large. The coupling degree of 2-（CRR）2R parallel mechanism is reduced to 1， which greatly reduced the difficulty of the positive solution of mechanism position and is conducive to the kinematics analysis. Based on the geometry and motion constraints， the one-dimensional search model of the position positive solution is established， then all the high precision position positive solutions are obtained by the golden section method. The inverse solution equation of the mechanism position is derived， and the correctness of the positive and negative solutions is verified by numerical examples. The velocity and acceleration of the moving platform are analyzed by vector method， the velocity and acceleration of the mechanism are obtained， and the numerical calculation is carried out by MATLAB. At the same time， simulation verification is carried out in Adams， the correctness of the degree of freedom analysis is verified. The kinematics analysis curve is consistent with the MATLAB calculation results， indicating that the analytical model and analysis method established in this paper is correct and feasible.关键词：Parallel mechanism;Structure coupling-reducing;Structure analysis;Kinematics analysis;Adams simulation
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发布时间：2022-10-03 - 摘要：Because of driving experience and comfort of electric vehicle， the working performance of its dive system must be well in the diving process. Structural analysis and dynamical system calculating of a two speed transmission are carried out， which based on a certain type of electric vehicle， and the flexible simulation model of the transmission system is designed and established based on Adams/View platform. The dive speed of electromotor in different gears is constructed by using Step function， and in the simulation conditions of 0~50 km/h and 50~80 km/h speed range， the kinematics characteristics and impact load on axle head which under first gear and second gear are calculated， analyzed and compared， on the basis of the results， the driving transfer process and variable speed performance of the transmission are verified. The dynamics optimization of input axis is carried out by modal analysis and zero order optimization algorithm， and then dynamic stability of the transmission system is enhanced effectively. All of above provide some technical reference for dynamic design and performance study of new energy vehicle transmission system.关键词：Electric vehicle;Step function;Flexible modeling;Optimization;Transmission;3D frequency spectrum;Dynamics
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发布时间：2022-10-03 - 摘要：In order to solve the problems of low load， low flexibility and low precision in the pouring operations of serial robots widely used in foundry production， a new type of hybrid heavy-duty pouring robot is proposed. A three-degree-of-freedom parallel working arm based on 2UPR-2RPU mechanism is designed，the topology analysis and degrees of freedom calculation are carried out. By establishing the kinematics model and statics model of the parallel working arm， the variation law of the length of the mechanism branch with the angle of the pouring ladle is analyzed. The relationship between the condition of the branch and the stroke size and the position of the branch on the static platform is analyzed. The structure and parameters of the parallel working arm are optimized. For a ladle of 300 kg， a set of structural parameters with better comprehensive properties is selected out. After prototype trial production and testing， the results show that the design proposal and structural parameters of the parallel working arm are reasonable.关键词：Pouring robot;Heavy duty;Parallel working arm;Force analysis;Optimum design
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发布时间：2022-10-03 - 摘要：A ship welding robot with variable topology structure is designed， which can change the numbers of its components to achieve the change of degree of freedom(DOF)， and to accomplish specific welding tasks such as complex welding， simple partial welding， horizontal welding and vertical welding， etc. Based on the theory of kinematic chain loop and Newton-Raphson method， the kinematics model of the mechanism is established， and the forward position solution is obtained. Then the law of velocity and acceleration is analyzed. Finally， the simulation result shows that the newly designed manipulator can meet the requirements of ship welding effectively.关键词：Ship welding robot;Variable topology structure;Kinematics;Simulation analysis
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发布时间：2022-10-03 - 摘要：Comprehensive consideration of the dynamic performance， driving range and energy consumption requirements of pure electric vehicles， on the basis of a fixed speed ratio pure electric vehicle as the research sample， in order to make the driving motor work point on the high efficiency area， two-speed Automatic Manual Transmission (AMT) drive scheme is put forward. The mathematical model of two gears AMT pure electric vehicle model and power system optimization model are established on Cruise simulation platform. Based on the Isight integration Cruise， the co-simulation process and platform of AMT pure electric vehicles are constructed. With 100 km/h acceleration time and the NEDC working condition per 100 km energy consumption as the optimization objectives， the maximum speed， the maximum climbable gradient and speed ratio constraint are used as constraints， the speed ratio of the powertrain are optimized， after optimization of the design variables， the reference two-parameter shift strategy in speed and load degree are established， in the meanwhile， a simulation research is conducted on the dynamic and economic performance of the vehicle with Cruise. The results show that， the NEDC consumption has reduced by 0.52 kWh/100km， the economic improvement rate is 3.78%， and the 100 km/h acceleration time has shortened by 2.23%.关键词：Pure electric vehicle;Powertrain;Co-simulation;Economic shift rule;Speed ratio optimization
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发布时间：2022-10-03 - 摘要：As an important part of automobile， the lightweight design of the driving axle housing must be carried out to meet the requirements of its stiffness and strength. In order to ensure the performance requirements， the traditional design concept generally adopts redundant design. Based on the integrated technology of CAD/CAE， the joint design between 3D mathematical model and finite element model is adopted， and the lightweight design of the driving axle housing is realized based on the size optimization algorithm of OptiStruct. The drive axle housing model created by CATIA is introduced into HYPERMESH for pre-processing， the calculation conditions and boundary conditions are designed and proposed. The statics， dynamics analysis and fatigue analysis are used to verify that the drive axle housing meets the use standard. Then the optimization analysis is conducted in the OptiStruct solver， and several iterative calculations are used to get the analysis result. The mass of the optimized axle housing is 152.042 kg， which is reduced by 50.075 kg， and the weight loss reaches 24.78%， and then the optimized drive axle housing is analyzed. Finally， the fatigue bench test of the optimized axle housing is carried out. The analysis and experimental results show that the optimized axle housing meets the test standard and a certain reference value for lightweight design of the same type is provided.关键词：Axle housing;Finite element method;Lightweight;Size optimization
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发布时间：2022-10-03 - 摘要：The tooth surface of the spur face gear is a kind of complex space curved surface, in order to realize the batch machining of complex space curved surface products with difficult cutting materials, the main technology of electrolytic machining is mainly used at present. Considering that electrolytic machining has some problems such as low efficiency of cathode design and difficult to guarantee the design accuracy in the machining of complex dissimilar surface products, an intelligent design method of cathode profile based on the characteristics of standard cathode is presented. Firstly, based on complex tooth surface grid planning principle, the coordinate of each sampling tooth surface is calculated by section lofting method. Secondly, by analyzing the curvature radius of each tooth surface sampling point, the design scheme of the corresponding cathode tool profile is constructed based on the theory of electrolytic machining equilibrium gap theory. Finally, using the GUI human-computer interface in Matlab, the intelligent cathode profile design system for spur face gear is constructed. Meanwhile the experimental shows that the machining accuracy of the cathode surface designed by the system is up to IT8.关键词：Spur face gear;Electrolytic machining;Equilibrium gap theory;Cathode profile;GUI human-computer interface
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发布时间：2022-10-03 - 摘要：Through the comparative analysis of the climbing mechanism of stair climbing wheelchair， a double crank type climbing mechanism is proposed. The design and research of the double crank type climbing mechanism is studied， and the kinematics model of the double crank climbing mechanism is established. Based on this， an analysis of the motion trajectory during the climbing process is carried out. The simulation results show that the structure of the climbing mechanism is reasonable， the scheme is feasible and the operation is stable to meet the design requirements.关键词：Stair-climbing wheelchair;Double crank climbing mechanism;Obstacle climbing;Kinematics analysis
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发布时间：2022-10-03 - 摘要：In order to solve some problems of embossing machine on the market today， a new parallel mechanism embossing machine with reasonable structure and simple control is presented. The overall structural scheme and outstanding features of the embossing machine are introduced， and the feasibility and practicality of this robot are discussed. The establishment of the mechanism composition and mechanism model of this parallel mechanism embossing machine is introduced. The kinematics mathematical model of the parallel mechanism embossing machine is established and the analytical form of the kinematics forward and inverse solutions is deduced to obtain its position， velocity and acceleration. Through the Adams software， the motion of the mechanism is analyzed， and the motion rule graph of the input and output components of the mechanism is obtained， and the motion law is analyzed to grasp its motion characteristics. The result of the kinematics study of the parallel mechanism embossing machine can provide reference for further research and optimization of the mechanism.关键词：Parallel mechanism;Embossing machine;Mechanism kinematics;Motion simulation
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发布时间：2022-10-03
Design· Calculation
- 摘要：Based on thin plate theory and thermal conduction equation in view of deformation effect， the thermoelastic coupling model of annular plate and the corresponding motion differential equation of friction plate in the friction clutch is established. The differential equation and the boundary condition are discretized by the differential quadrature method. The relation curves of the first three dimensionless natural frequencies of friction plate in friction clutch with the dimensionless angular velocity and the dimensionless thermolelastic coupling coefficient are obtained in a variable transverse temperature environment. The result shows that the first three dimensionless natural frequencies of friction plate increase with the increase of the dimensionless angular speed and the dimensionless thermolelastic coupling coefficient， and the different boundary conditions have a certain different effect on the increase of natural frequencies of friction plates， which provide the theoretical basis for design and performance analysis of friction clutch.关键词：Friction clutch;Friction plate;Transverse vibration;Thermoelastic coupling;Differential quadrature method
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发布时间：2022-10-03 -
Crankshaft Wear Fault Detection Method for Welding Robot Reducer based on Belief Rule Base Inference
摘要：Aiming at the nonlinear relationship between the welding machine servo motor torque signals and the RV （Rotate Vector） reducer crankshaft wear states， a wear fault detection method based on belief rule base inference （BRB） is designed. Firstly， the inputs of BRB system are considered as the mean values of the motor torques and torque derivatives， the outputs are set as the crankshaft wear fault levels. As a result， a belief rule base describing the mapping relationship between the inputs and the outputs is established. After the input signals are online obtained， the evidential reasoning （ER） algorithm is used to fuse the belief rules activated by inputs to obtain a belief distribution about the fault levels， and the degree of the crankshaft wear is evaluated by the distribution. Finally， using the measured torque data to verify the proposed method， it shows that the designed BRB fault detection method can largely replace the maintenance engineer to realize the automatic detection of the faults.关键词：Industrial robot;RV reducer;Crankshaft wear detection;Belief rule base;Industrial alarm system- 6
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发布时间：2022-10-03 - 摘要：In order to study the thermal elastohydrodynamic lubrication mechanism of bevel gears， based on the theory of elastohydrodynamic lubrication， a finite line contact model is established and the thermal elastohydrodynamic characteristics of straight bevel gears are studied. Firstly， the problem of the thermal elastohydrodynamic lubrication of the straight bevel gear is approximately equivalent to the pseudo-steady state thermal elastohydrodynamic lubrication problem of the two-way tapered roller. The multi-grid method and the sequential sweeping method are used to solve the oil film pressure， the oil film thickness and the temperature of the solid and oil film middle layers on the entire contact line of the bevel gear. The results show that the pressure， film thickness and temperature of the straight-toothed bevel gears are not the same at all points along the direction of tooth width. Among them， the oil film pressure of the small end is slightly larger than the oil film pressure of the big end， the oil film thickness of the small end is smaller than the oil film thickness of the big end， the temperature distribution difference along the tooth width direction is more obvious， and the temperature of the middle layer of the oil film is greater than the temperature of the two solid surfaces. A theoretical basis for the lubrication design of straight bevel gear is provided by this study.关键词：Finite line;Thermal elastohydrodynamic lubrication;Contact line;Oil film pressure;Oil film thickness
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发布时间：2022-10-03 - 摘要：In the process of gear fault feature extraction， empirical mode decomposition （EMD） has the problem of modal aliasing， intrinsic mode function（IMF） screening difficulty， and Wigner-Ville distribution（WVD） has cross-terms interference. So， a gear fault diagnosis method combining ensemble empirical mode decomposition（EEMD） decomposition and Choi-Williams distribution（CWD） is proposed. Firstly， the collected signal is decomposed by EEMD and decomposed into the combination of single component intrinsic mode functions. Then， the false components are removed and IMFs are screened through the correlation coefficient and Shannon entropy. Finally， the selected IMF components are expressed in CWD time frequency graph， and the gear fault features are extracted with the characteristics of frequency and isochronous impact exhibited in the time-frequency domain. Through simulation and experimental analysis， the applicability and effectiveness of this proposed method in gearbox gear fault diagnosis are verified.关键词：Gear;Fault diagnosis;Ensemble empirical mode decomposition（EEMD）;Choi-Williams distribution （CWD）
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发布时间：2022-10-03 - 摘要：The structure and working principle of the escapement type descending device for mining excavators are introduced. The reliability and dynamics performance of the descending device are theoretically analyzed. The three-dimensional structure of the descender is designed by CAD and UG software. The dynamics performance simulation is carried out with Adams software. The angular velocity and collision contact force of the main drive shaft are obtained respectively， and the stress analysis of the escape wheel is carried out. Finally， the performance of the test prototype is tested. The research results show that the mechanical structure of the escapement type descender does not show slipping during the falling process， and the strength and dynamics characteristics meet the requirements of use; the correctness of the simulation results is verified by experiments. The research results have a good guiding effect on the optimal design of the descending device.关键词：Computer aided design;Self-locking descending device;Dynamics simulation;Strength check
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发布时间：2022-10-03 - 摘要：In order to explore the vibration characteristics of a new type of intermittent mechanism—double meshing needle teeth cam indexing mechanism，considering the complex connection relationship between various components， the finite element model of the mechanism is established for modal analysis. The first six modal modes of the finite element model in the indexing and interval periods are extracted. Finally， the experimental modal analysis is performed on the prototype. The comparison shows that the natural frequency of the experimental modal analysis is similar to the finite element calculation. The reliability of the finite element modal analysis method is verified. According to the low order frequency of the intermission period， the structure resonance will not occur due to input. Through the modal analysis of double meshing needle teeth cam indexing mechanism， the experimental support and theoretical basis for vibration the characteristics analysis and the structural optimization design are provided.关键词：Cam indexing mechanism;Test modal;Modal analysis;Finite element method
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发布时间：2022-10-03 - 摘要：The three-dimensional geometric model of the driving and driven bevel gear， differential transmission planetary gear and half axle gear of driving axle main reducer is established by using three-dimensional software UG， and the non-interference assembly model is obtained and the creation of virtual prototype model is completed in the dynamic software Adams by which importing into with the common Parasolid graphics interchange format. Based on the Hertz elasticity contact theory， combining with the actual working status of driving axle for a sightseeing car， the dynamics simulation analysis of the starting， straight driving， turning working conditions are achieved by selecting appropriate contact parameters and applying corresponding constraints and loads. Reliable basis for the further research on kinematics and dynamics characteristics of driving axle main reducer and differential transmission gear is provided and technical support to reduce the vibration of the drive axle main reducer and differential transmission and optimize its performance characteristic is provided.关键词：Drive axle;Virtual prototype;Hertz theory;Typical working condition;Dynamics simulation
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发布时间：2022-10-03 - 摘要：Aiming at the dynamic problem of interrupt in the starting process of hybrid vehicle， a new scheme of starting engine with brake assist is presented. The control strategies of brake clamping torque control and torque coordination are designed， the simulation analysis and test verification are carried out. The test results show that the dynamic performance of engine start process is improved obviously. The result shows that the brake clutch assited scheme is reasonable， the control strategy is practicable.关键词：Series-parallel HEV;Engine start;Brake clutch assisted;Torque coordination control
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发布时间：2022-10-03 - 摘要：In order to solve the problem of high failure rate in the operation of planetary power shift gearbox for engineering vehicles， a dynamics simulation model of planetary gearbox is established based on the dynamics transmission theory， and the rotational speed， torque and transmission efficiency of planetary transmission components are analyzed. The ADAMS and Matlab simulation software are used to establish the virtual prototype joint simulation model of the gearbox， the dynamic performance of the gearbox under the forward working condition of the vehicle is simulated， and the transmission efficiency and power flow direction of the planetary gearbox are analyzed. The test results show that the speed change of the gearbox before and after gear shifting is relatively gentle， which shows that the new dynamic gear shifting strategy can reduce the gear shifting time of the gearbox and improve the dynamic response of the gearbox effectively during the operation of the engineering vehicle. The research results have practical significance for condition monitoring and power shift strategy formulation of planetary gearbox.关键词：Planetary gearbox;Dynamic characteristic;Transfer efficiency;Power flow direction
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发布时间：2022-10-03
Test·Analysis
- 摘要：Aiming at the nonlinear and unsteady characteristics of gearbox fault， a parameter-optimized Variational mode decomposition （VMD） is proposed to extract the characteristic frequency. Firstly， the Artificial bee colony algorithm （ABC） is used to adaptively select the number of layers and the penalty factor for VMD. Then， according to the mutual information method， the optimal finite Intrinsic mode function （IMF） is selected after VMD. Finally， the envelope spectrum analysis of the best IMF is performed to extract the characteristic signal of the gear fault. Comparing with Empirical mode decomposition （EMD） and VMD based on Particle swarm optimization （PSO）， simulation and experimental results show that the ABC-VMD method has strong adaptability， which can effectively avoid problems of mode mixing， signal loss and excessive decomposition. It can accurately perform early fault diagnosis on the gearbox and at the same time avoid the disadvantages of PSO-VMD falling into local optimum.关键词：Variational mode decomposition;Artificial bee colony algorithm;Envelope spectrum analysis;Gearbox fault diagnosis
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发布时间：2022-10-03 - 摘要：Plating CBN hard gear honing processing gear with standard involute， the general vicinity of the workpiece tooth pitch will be a “mid concave” error. The Pro/E software is used to establish three-dimensional parameterization entity model of gear-honing-tools and gears， and build meshing assemble between them accurately. ANSYS software is used to simulate the contact analysis of plating CBN hard honing process. Through the analysis of the contact stress of the tooth surface and the normal deformation of the processed tooth surface， the influence factors on the concave error are found out. Then，under the premise of other parameters are fixed， the tooth numbers of gears is changed respectively， comparing the change of contact stress， and then the influence of the teeth numbers to on “mid concave” error is found out.关键词：Hard gear honing;Parametric modeling;Tooth contact analysis;Tooth profile deviation
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发布时间：2022-10-03 - 摘要：In view of the problems existing in the defects detection for gear， a design scheme of the on-line detection system is proposed based on machine vision， and the functions such as image acquisition and display， image analysis and operation control are realized. The system controls the feeding equipment and the conveyor belt through the MCU control module， and using the photoelectric switch to trigger the high-speed camera to collect the image of the gear in real time. Then， by the industrial control machine preprocesses， the appearance quality information of the gear is obtained. Finally， the outputted signals of NG and OK are transmitted to the single chip computer to realize the sound-light alarm and sorting. Experiments show that the method has high accuracy and efficiency， and can meet the needs of actual production. It provides a new way for on-line measurement of gear.关键词：Gear;Machine vision;Single chip machine;Online system
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发布时间：2022-10-03 - 摘要：By using independent design method， the control module， figure module and thermal module of bionic hand are designed separately， the integration bionic hand is fabricated and can realization separation and assemble quickly. By using the Shape memory alloy（SMA）wire as actuator， the cam structure of displacement amplifier is designed， which can increase the output displacement of SMA in the driving process. Using Matlab， the simulation of kinematics and motion space is conducted， the bionic hand prototype is fabricated through 3D printing， which is 410 g. The response capability of bionic hand in different temperature environment and temperature protection for SMA are improved by temperature feedback， and grasping manipulation test for everyday objects is verified. Results show the novel bionic hand possesses the ability of grasping larger and heavier objects， and convenient disassembly and assembly， simple control， and stable grasping， which realizes the design of high integration.关键词：Integration;Cam device;Temperature feedback;Grasping experiment
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发布时间：2022-10-03 - 摘要：Study on three different induction tempering processes for a certain kind of change gear are carried out， and the results are compared with that of the traditional furnace tempering process. By contrastive analysis of the hardness distribution， microstructure， and also the residual stress distribution after tempering， all the above tempering processes are evaluated. The results show that the heating times of induction tempering has significant effects on hardness distribution， microstructure and residual stress. Compared to the single-pass induction tempering， the hardness distribution at the surface and root of the tooth was more uniform. Besides， multi-pass induction tempering could obviously improve the hardness uniformity， form fine tempered martensite structure and compressive residual stress at the tooth surface， which would help improve the toughness and fatigue strength of the gear. Furthermore， fatigue bending test is carried out to verify the feasibility of the induction tempering process.关键词：Gear;Induction hardening;Induction tempering;Residual stress
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发布时间：2022-10-03 - 摘要：As wind power transmission gear key parts， because of irregular under strong wind and Martin shock loads， so that its work reliability decides the reliability of the wind turbine gearbox. As one of the four requirements of gear transmission， an appropriate gear clearance is a necessary condition for the normal operation of the gear pair， which is the key to reduce the impact， noise， air distance error and improve the service life of the wind turbine gearbox. For the error of the gear pair clearance in planetary gear which is the first planet transmission structure forms of wind power gearbox， through analysis on the planetary gear pair clearance from three aspects of the impact， parts manufacturing， assembly and measuring， the influence of the assembly process of the planetary gear pair clearance is confirmed， through choosing the middle-box and the main bearings， the problem of the planet wheel gear deviation is solved.关键词：Wind turbine gearbox;Planetary gear;Gear clearance
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发布时间：2022-10-03
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