最新刊期
期 3 ， 2017
- 摘要：A compliant bistable mechanism is a device that can maintain two distinct positions without power input. There is a wide range of applications in the field of MEMS and mechanical transmission. Usually,the energy method is used for judging the steady state of compliant mechanism,but the driving characteristic of compliant mechanism can’t be analyzed. A new method for the steady state analysis of four bar mechanism based on dynamics is presented to analyze the driving characteristic of four bar mechanism with only a compliant joint.And according to the drive characteristic curve,the steady state characteristics of the flexible mechanism are judged. Firstly,the pseudo- rigid body model of the compliant four bar mechanism is established by using pseudo- rigid body method,and the dynamic equations are listed by using the Lagrange equation of the second kind. The change curve of driving force is calculated when the active member is rotated 360°. Then the corresponding flexible four bar mechanism model is established in ADAMS,and the simulation results are compared with the results of the dynamics calculation to verify the accuracy of the dynamics model. Finally,a numerical example is given to compare the dynamics analysis method with the traditional energy method. The results show that the dynamics analysis method is effective. At the same time,the critical value of the driving force in the process of steady state and non steady state position conversion are obtained,and a new method for the design of the flexible steady state mechanism is provided. At the same time,based on the dynamics characteristic of bistable state,the bistable switches and sensor can be designed and used.关键词：Compliant mechanism;Dynamics modeling;Driving characteristic;Bistable
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发布时间：2022-10-20 - 摘要：The Gears are applied widely,and are the key parts in many electric and mechanical equipments. A new kind of gears,the micro- segment gears are possible to replace involute gears in a lot of applications based on their superior performances,but they are limited in use since there are not test methods and techniques for the new gear. To be able to test the profile accuracy of the new gears,a test method is established for the gears by utilizing the current measurement method and equipment for the involute gears with considering the characteristics of the new gears,the theory equation of the new gear profile is given,some calculation formulas of systematic errors,such as the error of measuring heads and the clamping error are derived for gear measuring centers. A micro- segment gear is manufactured by hobbing and milling,and its profile error is measured,the results of the test illustrated that the measuring method for the micro- segment gear profile is practical.关键词：Micro-segment gear;Gear profile equation;Gear profile error;Precision measurement;Systematical error
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发布时间：2022-10-20 - 摘要：The model of water- lubricated hybrid journal bearings is established. The elastohydrodynamic lubrication of water- lubricated hybrid journal bearings are investigated with considering the fluctuation of supply pressure which due to the instability of throttling devices. The influence of film pressure and thickness of water- lubricated hybrid journal bearings caused by different forms of fluctuation in supply pressure is compared. The influence of elastohydrodynamic lubrication caused by load and entrainment velocity under fluctuation of supply pressure is analyzed,and the control basis supply pressure under different working conditions is obtained. The results show that the fluctuation trend of the supply pressure is the same as that of the film thickness and is opposite to that of the lubricating film pressure and the pressure fluctuation is not conducive to bearing lubrication. The larger entrainment velocity and the smaller load are helpful to relieve the damage caused by the supply pressure fluctuation to the lubrication. The basis of the fluctuation range of supply pressure under different working conditions is approximate obtained.关键词：Water-lubricated;Hybrid bearing;Supply pressure;Fluctuation
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发布时间：2022-10-20 - 摘要：Aiming at the problems which perform in the traditional driving mode,for example,the complex structure of motor drive system,the large volume of hydraulic drive system,the difficult control of air pressure drive system,a composite driving system actuated by micro- motor and shape memory alloy（ SMA） spring is proposed,then this system is applied to a humanoid multi- finger dexterous hand,the overall structure of the dexterous hand is simplified,and the control strategy gets optimized. The relation of the restoring force and displacement of the SMA spring is researched,then the relationships among knuckles movement and the influence factor on the contact force of grasping object are analyzed,by using the sliding mode PID intelligent control strategy,the movement of the finger is controlled,the control efficiency of dexterous hand is improved. Through the simulation of the dexterous hand model,the rationality and feasibility of the movement is verified,the basis for further study of composite driving system is provided.关键词：Composite drive;Shape memory alloy;Dexterous hand;Simulation
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发布时间：2022-10-20 - 摘要：The magnetic field modulated gear is a new technology,compared with the traditional mechanical gear,it can effectively avoid vibration,noise,lubrication and other issues. But its stiffness is low,which will lead to the transient oscillations undergoing the torque of prime motor is disturbance or the velocity changes.Based on the analysis of the basic principle of magnetic gear,a magnetic field modulated gear is designed,whose transmission ratio is 5. 5,and the performance of the magnetic gear with different structures is analyzed by using the electromagnetic field finite element method. A structure type with the highest efficiency is selected,in the iron core of high speed mover of selected gear by introducing damping winding with closed loop,in the process of transient oscillations,the current will be induced in the damping winding,which will produce damping electromagnetic torque can inhibit the mechanical vibration of transmission shaft and maintain the stability of system. In addition,the influence and variation law of the damping wingding parameters on the transient characteristics of magnetic gear are analyzed.关键词：Magnetic gear;Finite element;Loss;Damping wingding
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发布时间：2022-10-20 - 摘要：The field modulated magnetic gear is a kind of non- contact magnetic drive device,and the Halbach permanent magnet array is a new permanent magnet structure which contains permanent magnets with variable magnetizing directions. In order to recognize the magnetic field property and mechanical property of the field modulated magnetic gear with Halbach permanent magnetic array,the fundamental and harmonic components of the magnetization of the Halbach permanent magnetic array are expressed by Fourier expansion. By using finite element method,two magnetic gears with radial magnetization array and Halbach array are established respectively. The magnetic field and magnetic field harmonic in air gaps of two models are compared,and the torque- angle characteristics and cogging torque characteristics of the inner rotor and outer rotor of each model are studied. By contrast,the magnetic gear with Halbach array has a more smooth torque output than the magnetic gear with radial magnetization.关键词：Magnetic gear;Halbach permanent magnet array;Magnetic field;Torque ripple
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发布时间：2022-10-20 - 摘要：The analysis calculation of meshing stiffness of helical gear is the basis for the study of gear dynamics. According to the gear meshing principle and coordinate transformation theory the finite element model of helical gear meshing with the installation error is established,a finite element calculation method of the meshing stiffness of helical gear considering the installation error is proposed. Put the installation error parameterized,by using the finite element software,the variation of meshing stiffness of helical gears is analyzed. The time- varying meshing stiffness is got by the way of using the quasi- static process simulation dynamic behavior,the variation law of the time- varying meshing stiffness under different installation errors are analyzed. The results show that the installation error decreasing the meshing stiffness,especially the angle deviation is more serious,and the influence of the angle deviation on the meshing stiffness has a certain rule. The effect of different installation error of the meshing stiffness is different,under a light load condition is obviously heavy.关键词：Installation error;Helical gear;Meshing stiffness;Finite element
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发布时间：2022-10-20 - 摘要：The distribution of the gear temperature field has a significant impact on the gear tooth surface gluing failures,which have a significant impact on the reliability and gear service life. Based on frictional heat between gears meshing tooth surface produced by the asymmetric gear pair with a small teeth number,by using the space gear meshing theory,heat transfer and finite element method are used to analysis of the distribution parameters along the meshing line of frictional heat flow and its impact. The temperature thermal equilibrium equation of the temperature field of asymmetric gear with a small teeth number is established,and the finite element model of the gear pair is built. The frictional heat flows sequentially is loaded on the node unit successively by using ANSYS parametric design language APDL,and the accurate results of gear temperature field are obtained. The results know that,two peak positions of the temperature distribution are in the vicinity of the gear near the top of the tooth and the tooth root. The impact of gear geometry and working parameters on the temperature field changes are analyzed. Increase the displacement coefficient,the addendum sliding speed increasing,resulting in a temperature rise of gear,which provide a reliable basis for the design and optimization of gear lubrication improvement.
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发布时间：2022-10-20 - 摘要：Based on the type of DZLY180 gear reducer,aiming at the particularity of the tooth profile of point- line meshing gear,the curve equation of the tooth profile of point- line meshing gear is applied to calculate some coordinates on the tooth profile curve after modification. The cubic spline curves are used to fit the data,and 3D Software Solidworks is used to fit the tooth profile curve of point- line meshing gear. Then the three- dimensional modeling is carried out,the interference- free assembly of the gear is completed. The simulation results show that,the overall interference- free assembly in the meshing process of the point- line meshing gear is realized by the method.
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发布时间：2022-10-20 - 摘要：Aiming at the cycloid transmission in the cycloid planetary gear speed reducer used for robot,the analysis model for return clearance and mesh force calculation of cycloid transmission is set based on gear meshing theory and dynamic multi teeth meshing property. The influence of different tooth modification methods on the number of meshing teeth,force and distortion of each mesh point and the return clearance of cycloid transmission is calculated through iterative method. Furthermore,the influence of the load on the meshing characteristic is analyzed,and the stiffness curve of the cycloid transmission is obtained with the increase of load. It provides basis for the design and torsional vibration analysis of cycloid transmission.关键词：Cycloid transmission;Meshing characteristic;Return clearance;Tooth modification
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发布时间：2022-10-20 - 摘要：In order to solve the vehicle power discontinued transmission which influenced by the shift of the automated mechanical transmission and improve the shift quality,a new powertrain control strategy based on power shift is put forward. The traditional and hybrid powertrain interface based on this new strategy is designed. According to the result of the simulation and actual test,the comfort of driving and the continuity of power are obviously improved based on the power shift control strategy.关键词：Power shift;Powertrain;DCT;Hybrid powertrain control
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发布时间：2022-10-20 - 摘要：The hydro- mechanical continually transmission is compatible with the high efficiency of mechanical transmission and continual speed of hydraulic transmission,its structure depends on the position row layout of planets,and the structure of compound coupled HMCVT is to arrange the two planets in the input and output of the transmission. All 36 kinds of compound coupled HMCVT structure are listed,and one of the structure is selected,what is analyzed by MATLAB form transmission,hydraulic power distributing ratio and efficiency. The result suggests that the selected compound coupled HMCVT has a wide speed range and high transmission efficiency,and it can well meet the demand of all kinds of field operation of the vehicles.关键词：Hydro-mechanical continually transmission（HMCVT）;Compound coupled;Transmission characteristic;Efficiency characteristic
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发布时间：2022-10-20 - 摘要：The Gear rack is widely used in modern machinery,but it is easy to produce noise,wear and tooth surface scoring etc during the transmission process. Through research of the theory of mechanism lubrication to reduce the probability of tooth wear and tooth scoring during the transmission process. On the basis of the existing EHL theory,the EHL numerical solution of gear rack is obtained by utilizing the multi- grid method and the distribution of dimensionless pressure and film thickness under the effect of different mesh point,different modification coefficient,different ratio of line to angel and different modulus of the gear rack transmission mechanism are discussed. The results show that the position of mesh point,modification coefficient,ratio of line to angle and modulus are all have impacts on the oil pressure and film thickness. Eventually come to the conclusion that the meshing point is the dangerous point during the transmission process,the positive shift makes the oil film thicker while the negative shift makes the oil film thinner,the more ratio of line to angle and modulus,the smaller pressure and the thicker the film thickness.关键词：Gear rack;EHL;Pressure;Film thickness
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发布时间：2022-10-20 - 摘要：In order to reduce the edge effect,the tilting and skew effect of the roller. Using the Eyring Non- Newtonian fluid model,the parabolic modification function is applied to a finite line contact thermal EHL model. The pressure is solved with multilevel method and the temperature is calculated with sequential column sweeping technique. A special coordinate transformation technology is used for the solving of cylindrical roller skew. For the tilting rollers,the initial value of a dimensionless load offset distance Ew is given,and then the oil film pressure,the film thickness,and the dimensionless moment M are obtained. Moreover,the relative error of torque Err M is calculated,and a new value of the load is obtained simultaneously. when the roller is at the ideal,the tilting,the skew or the tilting coupled with the skew status,the profile modification for the roller generatrix can reduce the edge effect and the tilting or the skew effect. In addition,an optimum value of the profile modification for the roller generatrix exists at the four kinds of status. The optimum value is 9,11,14 and 16 mm at the four status. The method which a profile modification function is added on the straight roller generatrix is simple and feasible. A new idea for the engineering application of the roller profile modification is provided.关键词：Thermal EHL;Finite line contact;Non-Newtonian fluid;Tilting coupled with skew roller;Roller profile modification
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发布时间：2022-10-20 - 摘要：A flexure hinge positioning stage with giant magnetostrictive actuator（ GMA） as the driving unit is designed,which is composed of multi- group flexure hinges and guided by elastic deformation under force. The theories of the energy equation,equation of deflection curve,axioms of statics and energy conservation equation are applied to establish the mathematic theory model of flexure hinge positioning stage. The driving force and output displacement of the flexure hinge positioning stage are analyzed on the basis of working requirements driven by GMA. The geometric parameters of radius R and minimum thickness t of flexure hinge are optimized to achieve the optimized structure parameters of the flexure hinge positioning stage. Finally,the flexure hinge positioning stage is simulated by finite element analysis and the simulation values and theoretical analysis values are compared,the accuracy of theoretical analysis is verified.关键词：Flexure hinge;Positioning stage;Optimal design;Finite element analysis（FEA）;Giant magnetostrictive actuator（GMA）
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发布时间：2022-10-20 - 摘要：In order to change the status of the traditional manual harvesting artificial shrubbery time- consuming,a track- type brush cutter is designed to replace manual labor. Through analyzing the coordinate relationship between the traveling speed and cutting speed of the traditional small self- propelled shrub brush cutter,when the brush cutter in harvesting operations on the bush,the transmission system is the non- continuous transmission function output. So the best coordinate relationship between the traveling speed and cutting speed can’t be got. In order to meet to the requirements of improving the efficiency of small- size self- propelled brush cutter,the optimization design of transmission system of the brush cutter is carried out based on traditional experience design. By determining the objective function of the transmission system,selecting the independent design variables,determining the constraints,the mathematical model of transmission system is established.The analysis and optimization of the design variables,objective function and the boundary conditions are carried out,the complex method optimization program of MATLAB is written,and by using its powerful ability of optimization design to optimize the transmission system of the brush cutter. The optimization results show that,the work efficiency is improved by 20. 59% than the traditional design of small crawler artificial shrub cutter. The design method and the theoretical basis for improving the cutting operation efficiency of the brush cutter are provided.关键词：Transmission system;Optimization design;Complex method;Matlab
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发布时间：2022-10-20 - 摘要：Taking a high- speed motor train unit transmission gear system as an example,by using gear analysis software KISSsoft,the deformation of gear supporting axial in the transmission process is calculated.Through the method of modification to compensate the influence of the shaft deformation on the gear meshing performance. Then,the difference between before and after the modification of gear meshing contact spot,tooth surface line load distribution and the transmission error,etc are compared to ensure the motor train unit gear transmission system working more stable and reliable. The work of the research has important reference value to the design of the motor train unit gear pair.
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发布时间：2022-10-20 - 摘要：The gearbox is widely used in ships,studying its gear temperature field to avoid gear scuffing failure has larger significance. The rising temperature field by friction on gear tooth surface are simulated through the in- depth analysis of spray lubrication process of shipping helical gear,then the computational fluid dynamics（ CFD） method of spray lubrication process is established. Three types of spray ways including spray lubrication through engaging- in direction,spray lubrication through engaging- out direction,and spray lubrication through both engaging- in and engaging- out directions are calculated,and heat transfer coefficient of oil / air on meshing tooth surface of helical gear are obtained under different spray ways. The influence of different spray ways on meshing surface are compared under the influence on temperature with different heat transfer coefficient. The results show that,for better cooling effect,the oil should be sprayed both in engaging- in and engaging- out directions. The velocity of oil in the two directions depending on the structure,working condition of helical gear,but a better cooling effect has been calculated with 15 m / s in engaging- in and 45 m / s in engaging- out in this model.关键词：Helical gear;Spray oil mode;Computational fluid dynamics;Heat transfer coefficient;Spray oil velocity
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发布时间：2022-10-20 - 摘要：In order to meet the requirements of strength and service life of steel belt in the transmission process,the mechanical property of the transmission steel belt is analyzed,and comes to the conclusion that the main reasons for the changes of the steel belt stress are the initial tension,the thickness of the steel belt,roller diameter,and finds out where the maximum stress may occur. At the same time,based on theory,the kinetic and dynamic characteristics of steel belt are analyzed. Finally,by using the Recur Dyn software,steel belt is stimulated,the relevant dynamics and kinematics curves are got and compared with the theoretical analysis,a reference for the design and calculation of steel belt is provided.关键词：Steel belt;Mechanical property;Maximum stress;Recurdyn;Simulation
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发布时间：2022-10-20 - 摘要：The assembly conditions of 2K- H planetary transmission is analyzed,and the conclusion that the first planetary transmission in RV reducer don’’t need to meet the assembly conditions is put forward. On the basis of considering the manufacture technics and interchangeability,the interchangeability conditions are put forward. The tooth matching method of RV reducer under the interchangeability condition is introduced and used to design the toothed parameters of RV- 80- 120 RV reducer. The results show the correctness and effectiveness of this method.关键词：RV reducer;Assembly condition;Tooth matching method;Interchangeability condition
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发布时间：2022-10-20 - 摘要：The test of face gear transmission under the high- speed and heavy- load requires high performance test equipment. In order to simplify the experiment condition and reduce test cost,the similarity theory of the tooth root bending stress and vibration acceleration is obtained based on the dimensional analysis theorem. The tooth root bending stress and vibration acceleration of face gear under high- speed and heavy- load conditions are measured by the experiment. The bending stress and vibration acceleration of face gear under high- speed and heavy- load conditions are estimated by using the analogical relationship between the face gear prototype and the similarity model establishing with similarity criterion. The prediction of strength and dynamic performance of high- speed and heavy- load face gear under the is realized.关键词：High-speed and heavy-load;Similarity experiment;Dimensional analysis;Tooth root bending stress;Vibration acceleration
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发布时间：2022-10-20 - 摘要：Taking the measured gearbox vibration signals as the analysis object,the fault feature of gear pitting is extracted. The Akaike Information Ceriterion（ AIC） is applied to evaluate the optimum Auto- regressive（ AR） model order,and then this AR model is used to pre- process the vibration signals to eliminate the linearly predictable stationary part. The Maximum Correlated Kurtosis Deconvolution（ MCKD） is applied to enhance the impact component. The fault characteristic could be identified by analyzing the envelope spectrum.And the AR- MCKD method is applied to analyze the changing trend of the vibration signals. The results proved the efficiency of the AR- MCKD method in the gear fault feature extraction and the changing procedure of the envelope spectrum of gear pitting fault.关键词：Gear fault diagnosis;AR model;Maximum correlated kurtosis deconvolution;Envelope spectrum
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发布时间：2022-10-20 - 摘要：The finite element model of the static mechanics simulation result of rolling- sliding bearing is uses as a model for fatigue analysis,and the load cycle variable of the fatigue analysis is the time stress variation law of the dynamic simulation results of rolling- sliding bearing. The fatigue life simulation of cylindrical roller bearing and rolling- sliding bearing is carried out by using the n Code Design Life fatigue analysis software,the cloud picture of life and damage of two kinds of bearing are got,the parts easily damaged of two kinds of bearing are determined from the cloud picture. The fatigue life test of two kinds of bearings is carried out on the experimental machine,and under the premise of meeting the fatigue strength,concluded that the damage of the parts of the rolling- sliding bearing is less and the anti fatigue ability is stronger. Therefore,the rolling- sliding bearing has higher reliability performance.关键词：Cylindrical roller bearing;Rolling-sliding bearing;nCode DesignLife;Fatigue life
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发布时间：2022-10-20 - 摘要：The asymmetric helical gear with a small number of teeth as a new type gear has the advantages of small volume and strong bearing capacity,but the analysis of its dynamic characteristics especially research on the influence of elastic contact impact on the stability of gear transmission system caused by instantaneous normal relative velocity is less. Based on contact- impact dynamics equations,the finite element dynamic contact model of asymmetric helical gear with a small number of teeth is built,the dynamic tooth root bending stress and the dynamic transmission error are investigated under the condition of considering the effects of friction and damping,etc. The dynamic distribution of tooth root in a meshing period of the bending stress is described. The static and dynamic bending stress of tooth root in the whole meshing process of the helical gear pair is compared,and the influence of operating parameters on the bending strength is analyzed. Due to the elastic impact caused by instantaneous normal relative speed difference of gear contact point is analyzed. Taking the instantaneous impact process of the asymmetric helical gear pair with a small number of teeth as the research object,the different impact position（ tooth root,the pitch circle and tooth top） on impact force,impact stress and impact time under different speed are analyzed,and the impact stress of asymmetric helical gear and symmetric helical gear are analyzed and compared.关键词：Small number of teeth;Asymmetric gear;Dynamic characteristic;Transmission error;Impact dynamics;Elastomer
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发布时间：2022-10-20 - 摘要：The dynamic numerical simulation of inner oil bath lubrication flow filed of a type locomotive gearbox is carried out by using dynamic mesh and Profile technology based on CFD software Fluent. A two- dimensional VOF multiphase model of the gearbox is built,the dynamic characteristic of the inner flow filed is calculated as the input velocity of the gearbox varied during the 3 speed（ starting at low speed,medium speed,maximum speed）. The phase,pressure and velocity distribution of internal flow field of the gearbox under different speed condition are obtained. The simulation results would provide a theoretical basis for the design and maintenance of the gearbox.关键词：Gearbox;Oil bath lubrication;Multiphase flow;Numerical simulation
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发布时间：2022-10-20 - 摘要：As an important part of automobile,the vibration characteristics of automobile transmission have important influence on the performance of the automobile. By studying and analyzing the vibration characteristics of an automobile transmission,the response of different position in different directions of the automobile transmission shell can be obtained. Through the analysis,the dynamic response of the automobile transmission is initial determined,the optimal excitation direction,natural frequency and frequency band of the automobile transmission are obtained. Through the experimental analysis,these parameters are obtained,the inherent characteristics of the automobile transmission is known,the foundation for the next step to analyze and optimize the structural optimization of the automobile transmission is provided.关键词：Automobile transmission;Vibration characteristic;Natural frequency;Frequency band
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发布时间：2022-10-20 - 摘要：In order to guarantee the structural safety and reliability as well as sufficient strength and stiffness of heavy load ball screw assembly of tundish car,the contact statics analysis of the ball screw assembly is conducted by the finite element software ANSYS,and the impact of contact angle and load on the stress and deformation of ball screw assembly is explored. The results show that the maximum stress of the ball screw assembly is 1093. 7 MPa,which is smaller than the allowable stress of the structure and therefore satisfies the requirements of stiffness and strength. Moreover,the contact stress and deformation of the ball screw assembly decreases with the increasing of the contact angle and increases with the increasing of the load.关键词：Tundish car;Ball screw assembly;Heavy load;Contact analysis
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发布时间：2022-10-20 - 摘要：In order to improve the accuracy of tooth profile deviation in machine,a method which can get the radial error based on the actual working condition is proposed. According to the principle of polar coordinates measuring and tooth profile deviation calculation,an optimization model with purpose of minimum tooth profile and variable parameter of radial error is established based on the object of standard involute spur gear.After resolving this radial error and compensating the machine with the error,a helical involute gear is measured and the measured result is compared with the testing result of the three coordinate of the testing results of the three coordinate measuring instrument,the rationality of the radial error solving of the measuring head is obtained.关键词：Radial error;Tooth profile deviation;Radial compensation
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发布时间：2022-10-20 - 摘要：The torsional vibration model of the spur gear system with time- variant mesh stiffness,nonlinear clearance and the mass eccentricity caused by tooth breakage is established. The primary resonance and combined resonance of the model with tooth breakage are analyzed by multi- scale method. Then the different mass eccentricity causes the different bifurcation mode of the gear system by the singularity analysis,which comprehensively shows the dynamics mechanism of the tooth breakage fault. The results obtained herein can provide a theoretical basis for broken fault diagnosis of gearbox.关键词：Gear system;Tooth breakage fault;Primary resonance;Combined resonance;Multi-scale method
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发布时间：2022-10-20 - 摘要：The methods of the tooth root bending fatigue test both at home and abroad are introduced,and several questions about single tooth pulsating test are explained and discussed,such as ensure the load distribution along tooth length direction,clamped tooth number and loading point position,the loading frequency and the tooth form factor,stress concentration factor and tooth root surface condition factor for calculation and so on.关键词：Tooth root bending fatigue;Single tooth loading;Loading point
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发布时间：2022-10-20 - 摘要：The cycloid pin gear reducer has the characteristics of small size,large output torque,and widely used in robotic joints. A set of equations is presented to optimize the cycloid pin gear reducer with pillow needle tooth structure instead of the cantilever type tooth structure,which is of compact and high strength. A genetic algorithm is used to optimize the structural parameters of reducer. The smallest volume,minimum mass and maximum efficiency are set as objective functions,the relevant constraints conditions are derived on the basis of Hertz formula,etc. On this basis,the optimization of reducer key structure parameter is carried out,and the simulation analysis is carried out by using the finite element method. The results show that the reducer meets the design requirements,the optimization is valid and valuable on engineering application.关键词：Cycloid pin gear reducer;Genetic algorithm;Structural optimization;Contact analysis
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发布时间：2022-10-20 - 摘要：Aiming at the problem that working condition is complex in fact so that it is difficult to extract the gear fault feature frequency,a method of gear fault diagnosis based on variational mode decomposition（ VMD） and multi- feature fusion is proposed. Firstly,the mechanical vibration signal is decomposed into a series of modes by using VMD method. Then,the permutation entropy（ PE） value and energy of the first four modes of high frequency is calculated. Finally,the high- dimensional feature vectors composed of PE and energy are transformed as input of least squares support vector machine（ LS- SVM） to identify gear fault types.The experimental results indicate that VMD can better separate complex multi- components signal from each other,the PE and energy feature can reveal the gear fault information from different scales,the intelligent fault diagnosis method based on VMD and multi- feature fusion can identify the operating conditions of gear accurately and provide reference for the gear fault warning and severity.关键词：VMD;Multi-feature fusion;LS-SVM;PE;Fault diagnosis
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发布时间：2022-10-20 - 摘要：For the problem that the characterization of the gear fault signal feature is difficult to extract and the structure parameters selection of support vector machine（ SVM） are based on experience leads the poor precision and generalization ability of fault state recognition,a method that IPSO- SVM rolling bearing fault diagnosis based on the Hilbert envelope spectrum singular value is proposed. Firstly,the rolling bearing signal is divided by EMD,it selects IMFs that contains main characteristics of signal for Hilbert demodulation envelope analysis to obtain envelope matrix and the singular value decomposition is carried out. Secondly,the IPSO algorithm is used to optimize the penalty coefficient and the structural parameters of SVM to set up the rolling bearing fault classification model. And by using the bearing data of Case Western Reserve University,the validity of the method is verified. The experimental results show that IPSO- SVM rolling bearing fault diagnosis based on the Hilbert envelope spectrum singular value compared with the fault classification model based on BP,SVM has higher precision and stronger generalization ability.关键词：EMD;Intrinsic mode function;Partical swarm optimization;SVM;Rolling bearing
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发布时间：2022-10-20 - 摘要：In order to improve the effectiveness of bearing fault feature information extraction,the intelligent recognition of bearing fault pattern is realized,and the efficiency of fault diagnosis is improved. The method of rolling bearing fault diagnosis is proposed,which combined with de- noising of singular value decomposition and fuzzy LMD feature quantification and PNN neural network recognition. In this method,firstly,the original signal is reduced by using SVD noise reduction technique,and the LMD decomposition is used to decompose the non- stationary signal into a number of stable product function components（ PF）. Secondly,because the fuzzy entropy can be used to characterize the complexity of time series and the stability of statistical property. The fuzzy entropy of PF component is extracted to form N dimension feature vector. The PNN network model is constructed,the feature vector is input PNN model to realize the fault type identification. Finally,the performance of the PNN algorithm and BP algorithm are compared,and the superiority of the PNN algorithm is shown. The experimental data show that the proposed method has a high accuracy rate of 93. 75% in the case of a small number of data samples.关键词：Singular value decomposition;Local mean decomposition;Fuzzy entropy;Probabilistic neural network;Bearing fault diagnosis
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发布时间：2022-10-20 - 摘要：The inter- axle differentials as a core component of power transfer cases is used to achieve the distribution of chassis power and meet the needs of working conditions of vehicle cornering and climbing,which has played a key role in ensuring the reliability of the vehicle power transmission. By using the two- stage optimization method,the inter- axle differential planetary wheel structure optimized design is carried out,on the one hand to ensure the strength of the structure,on the other hand to reduce the quality of products to meet the requirements of the vehicle light weight and high maneuverability. By the checking of classic strength calculation and finite element method,it shows that the optimization program could meet the requirements of both high torque and high- reliability design of the planetary gear inter- axle differential of multi- axis ultra- heavy-duty chassis large power transfer case.关键词：Transfer case;Inter-axle differential;Planetary gear;Optimization design
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- 173
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发布时间：2022-10-20 - 摘要：According to the actual situation of the construction site and the problems of the oilcan spraying robot,such as spraying inefficiently,can’t adapt to the size of each oilcan,can’t meet the use of sand blasting and spray painting,an oilcan modular smart spraying robot is designed. The overall structure and the key components of the robot are described. The designed robot can realize some functions,like automatic lifting,rotating,the movement of the spraying car,the adjustment of spray gun angle,visual feedback,etc by the detection of machine vision and the intelligent judgment. This robot can adapt to the size of each oilcan by adjusting the number of boom sections and the fixed column sections. It can be used both for sand blasting and spray painting. At last,the modeling and analysis of booms and the fixed column as the key structure of the spraying robot are carried out. The result shows that the key structure will not resonate in the work.关键词：Oilcan spraying;Spraying robot;Mechanical structure;Vibration analysis
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发布时间：2022-10-20 - 摘要：In the actual manufacturing process of globoidal cam,due to the processing surface of globoidal cam is always considered as symmetrical structure,hence the interference between the tool and the workpiece is easy to be formed. Aiming at the processing problem,the design theory of offset type redundant globoidal cam is proposed. Through the double cannelure,the redundant drive surface is designed,the loading capacity of globoidal cam is improved. By using the MATLAB and UGNX software,the precise calculation,modeling of the offset type redundant globoidal cam are carried out.关键词：Offset structure;Surface design;Redundant mechanism;Globoidal cam;3D Modeling
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- 87
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发布时间：2022-10-20 - 摘要：Based on the characteristic that is the weak fault feature extraction of rolling bearing is very hard under strong background noise,a new method of rolling bearing fault diagnosis based on Fourier decomposition method（ FDM） and 1. 5- dimensional Teager energy spectrum is proposed. The first,the fault signal is decomposed into a number of intrinsic band functions（ FIBFs） which instantaneous frequency has physical significance. Then,the fault signal is reconstituted by using the method of correlation coefficient to screening intrinsic band functions. The last,the fault feature frequency is obtained by using 1. 5- dimensional Teager energy spectrum to the reconstituted signal and the result can be seen. Simulation results show that compared with the traditional envelope spectrum,this method has more obvious fault features and the effect is better. Finally this method is successfully applied to the actual rolling bearing fault diagnosis,further verify the effectiveness of the proposed method.
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发布时间：2022-10-20 - 摘要：In order to satisfy the test requirements of transmission efficiency of heavy vehicle drive axle,the test bench of transmission efficiency for heavy vehicle drive axle is designed. The structure,principle and the key parts of the test bench are introduced. Aiming at the problem of the lack of heavy vehicle drive axle transmission efficiency industry test standards in domestic,a test method for heavy vehicle drive axle transmission efficiency is presented referring to the test standard QC / T533- 1999 Vehicle Axle Bench Test Methods and QC / T568. 1- 2011 Vehicle Mechanical Gearbox Assembly Bench Test Methods Part 1: Minicar and combining with heavy vehicle drive axle actual working conditions in domestic. Then the transmission efficiency test for a heavy vehicle drive axle is conducted. The test indicates that the test bench has a superior controlling accuracy and measuring precision and can fully meet the test requirements.关键词：Heavy vehicle;Drive axle;Transmission efficiency;Test bench;Test method
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- 254
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发布时间：2022-10-20 - 摘要：To clarify the significant revision of the new version international accuracy standard of the standard ISO 1328- 1: 2013（ E） based on the principles and frames of the old version of the standard ISO 1328- 1: 1995. The difference between two versions of ISO 1328- 1 is compared,including the definition and evaluation method of accuracy level,applications range,and elemental deviations（ pitch,profile,helix）,and measurement items and the number of teeth. Especially the tolerance value calculated through the formula in the new standard and the allowable values provided in the list table of the old one is compared and analyzed. The changes can be found from the results as follows: the accuracy level range is from 1 to 11 in new standard,pitch circle diameter d increase to 15 000 mm and tooth width b increase to 1 200 mm respectively in applications,the form and slope deviations are the compulsory measurement items,the regulation of the minimum number of teeth measured are added in,the definition and evaluation method of the elemental deviations are revised,the big difference can be found between the tolerance value of elemental deviations in new standard and permissible value given in the list in old one,which is dozens of micron at 5 grade of accuracy level,and hundreds of microns at 11 grade of accuracy. There is no doubt that big difference exist between the two versions of the cylindrical gear accuracy standard,which has changed the basis of the accuracy evaluation of the gear elemental deviations and will contribute to a series of revision of other related standards. More attentions should be paid by someone involved including standard development,gear measurement instrument design and gear quality management.关键词：Gear;Accuracy standard;ISO 1328-1（E）;ISO 1328-1;Elemental deviation
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发布时间：2022-10-20 - 摘要：The research of the representative aero engine accessory gearbox structure design method and the analysis of the structure characteristics of the important components including the casings,gears and bearings are accomplished. The failures and questions occurred in the accessory gearbox components used for a long term are summarized,the applying suggestion of engineering application optimized structures are proposed,which contributes to the reference of high reliability accessory gearbox design.关键词：Aero engine;Accessory gearbox;Structural form;High reliability
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发布时间：2022-10-20
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