最新刊期
期 10 ， 2016
- 摘要：Under condition of zero torque,speed ratio is different even if continuously variable transmissions（ CVT） have the same control pressure. In order to investigate the phenomena,the thrust balance model and its impact factors is researched under no load condition. The theoretical balance thrust ratio is calculated under no load condition. Through test bench experiment,impacts on balance thrust ratio from speed ratio,secondary pressure and primary pulley speed are researched. The theoretical model shows that balance thrust is proportional to the ratio between primary and secondary working wrap angle,and this analysis results is verified through test bench experiment. Other experimental results are as follows. Speed ratio impacts thrust ratio significantly through a monotonically decreasing relationship and this relationship is not affected by secondary pressure. Impacts from primary pulley speed can be ignored. The balance mechanisms of thrust ratio under no load condition is researched and theoretical and experimental basis for further research on transmission principles between CVT and metal belt is provided.关键词：CVT;Cone pulley thrust;Balance model;No load condition
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发布时间：2022-10-20 - 摘要：During the sliding process of multi- disc clutch,the heat partition coefficient between friction components is affected by the disc thickness and material property. For the discs with finite thickness,a coupled heat conduction model is established,based on which the disc temperature fields and the heat partition coefficient are obtained at the same time. The results show that,the heat partition coefficient is a constant at the very beginning and varies to another steady- state constant after a short time rise. Comparing this heat partition coefficient with the constant value obtained by the semi- infinite model,it’s found that the latter can only determine the initial heat partition coefficient. Experimental results show that,the temperature field calculated with variable heat partition coefficient is very close to the measured temperatures. However,the temperature field predicted with the constant heat partition coefficient overestimates the separator disc temperature and underestimates the temperature of the friction disc.关键词：Mechanical engineering;Multi-disc clutch;Heat partition coefficient;Temperature field;Finite element method
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发布时间：2022-10-20 - 摘要：To study the dynamic load sharing characteristics of two- stage planetary gear train,a translation- torsion coupling dynamics model is established by taking the nonlinear factors like time- varying mesh stiffness,position error,eccentric error,gear backlash and coupling stiffness into account,and the dimensionless dynamics differential equations for the system are derived and solved by numerical method. The effects of floating components,planetary gear error and coupling stiffness on the load sharing characteristics are analyzed.The research work has guiding significance for the design of multi- stage planetary gear train,and the reference basis for the research of dynamics analysis and dynamic load sharing characteristic of two- stage planetary gear is provided.关键词：Two-stage planetary gear;Transverse-torsional coupled;Nonlinear;Dynamic load sharing characteristic
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发布时间：2022-10-20 - 摘要：The motion analysis of 3- RRS spherical parallel mechanism is carried out by using the screw theory. The forward kinematics of 3- RRS spherical parallel mechanism is solved by using Newton iterative method. The inverse kinematics model of 3- RRS spherical parallel mechanism is established by using closed loop vector method. The corresponding inverse position solution formula is derived. Eight sets of inverse solutions are obtained. Through the example analysis,the validity of the position solutions of 3- RRS spherical parallel mechanism is verified. The reachable workspaces of 3- RRS spherical parallel mechanism are solved with the help of numerical search method. The reachable workspace diagrams with different structure parameters are drawn by using Matlab software. The variation law of the workapaces is analyzed. The results lay the foundation for the application of 3- RRS spherical parallel mechanism.关键词：3-RRS spherical parallel mechanism;Screw theory;Forward position solution;Inverse position solution;Workspace
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发布时间：2022-10-20 - 摘要：According to the principle of forming principle and modeling method of the cycloidal gear tooth profile,the mathematical model of the form grinding is established and the calculation formulas for axial section coordinate points of the grinding wheel are deduced. The profile equation of the grinding wheel is obtained through studying the theory of grinding wheel widened. The trajectory for the diamond wheel when dressing grinding wheelis solved based on the principle of equal distance curve. The software for form grinding wheel dressing is developed and the simulation and analysis of grind wheel modified is got by the modification method of "isometric + shift".关键词：Forming grinding;Cycloidal gear;Wheel modification;Axial section
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发布时间：2022-10-20 - 摘要：In order to optimize the performance of excavator in the specific region,The mathematical model of optimization design is obtained constrained by operating performance and mechanical property of the working device. The parameter of working device in the anti shovel hydraulic excavator are integrated optimized by using the hybrid algorithm of simulated annealing and penalty function. The efficiency and accuracy of the solution is improved for the advantages of two algorithms are effectively combined and local optimal solution is avoided. The optimization and simulation of the working device are realized by using the Matlab programming,the defects of the original design are corrected and the performance of the whole machine is greatly improved.关键词：Working device;Simulated annealing;Penalty function;Hybrid algorithm;Parameter comprehensive optimization;Excavating performance;Matlab
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发布时间：2022-10-20 - 摘要：Based on the rigid-flexible coupled multi-body dynamics theory,with software of three-dimensional solid design,on the basis of finite element software and multi-body dynamics software,the coupled dynamics simulation model of double cross universal joints is created. The flexible characteristic of intermediate shaft hollow section is taken into consideration in this model. The mode analysis of intermediate shaft is carried out and modal neutral file is obtained. To study the influence of angle size that formed among input shaft with intermediate shaft and output shaft with intermediate shaft on transmission uniformity,the dynamics simulation analysis in three kinds of misalignment angle are carried out. The research results show that the less difference in angle size of input shaft between intermediate shaft and output shaft between intermediate shaft,the smaller inhomogeneity in the rotation,it is consistent with the universal joint transmission theory. The modeling and analysis method provides a reference way to design and optimize the cross universal joints.关键词：Double cross universal joints;Mode analysis;Rigid-flexible coupling;Dynamics simulation
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发布时间：2022-10-20 - 摘要：The periodic change of gear pair meshing stiffness is the main internal motivation of gear system vibration,taking the external meshing model of the straight tooth cylindrical gear pair as study object,considering the influence of tooth contact characteristic on the gear stiffness,the contact analysis of finite element model of the gear pair is established,the gear meshing stiffness is calculated,the change situation of gear meshing stiffness is discussed with gear in the case of the axial load and under different load cases. In view of the stress distribution of contact area,the changing reason of the meshing stiffness is researched. It is found that gear meshing stiffness decreased with the increase of axial load. When the meshing gear is subjected to variant loads,the stiffness increased in a linear pattern with the increase of load,and it tended to remain stable after reaching a certain degree.关键词：Straight tooth cylindrical gear;Meshing stiffness;Axial partial load;Contact area
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发布时间：2022-10-20 - 摘要：To improve the aero- engine fault diagnosis accuracy grade,by using the DET and PNN classification techniques,a bearing fault diagnosis technique based on feature selection and PNN is put forward.Firstly,the bearing fault test data are extracted to form the multi- domain fault diagnosis feature set composed of 14 time- domain features and 13 frequency- domain features. Secondly,to increase classification efficiency and reduce the influence on classification result from coupling characters between features,the feature selection technique based on DET is applied to obtain feature parameters which can be classified easily. On this basis,the PNN technique is applied to carry on research of bearing fault diagnosis. The bearing simulation fault experiment data is applied for verification,the results prove that compared with diagnosis techniques of BP neural network and support vector machines,the PNN is higher in the respect of diagnosis accuracy grade. Meanwhile,the efficiency and accuracy grade of diagnosis are further improved for the reason of employing feature selection technique.关键词：Aero-engine;Bearing;Fault diagnosis;Feature selection;PNN
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发布时间：2022-10-20 - 摘要：The cycle power,which is prone to appear during shifting process for a wet dual clutch transmission,the life of the clutch is severely affected and the shifting quality is decreased. In response to this phenomenon,the up- shift dynamics equations are derived according to the detailed analysis of up- shifts and the study on the cause of cycle power,during up- shift process of a DCT. Furthermore,the relationship between throttle position,changes in oil pressure and cycle power in the up- shift process is analyzed. The solutions to suppress the cycle power is proposed. A PID method is used to adjust the engine speed by controlling the throttle position. On the basis of disengage clutch and engage clutch,using the fuzzy control theory,taking the driver intention,the deviation of engine speed and target speed as inputs and taking the rise rate of oil- filled pressure as outputs,the up- shift control strategy is designed. It is concluded that the strategy can reduce cycle power effectively and shorten slip energy,jerk. The shifting quality is optimized.关键词：Wet dual clutch transmission;Up-shift control strategy;Cycle power;Fuzzy control
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发布时间：2022-10-20 - 摘要：The isomorphism identification of structural type is a vital problem now. For dealing with the isomorphism generated in synthesis of planar configuration based on the synthesis method of Assur- group adjacency matrix,a methodology of Assur- group adjacency matrix isomorphism identification is proposed. First of all,according to the diagonal elements is derived by the amount of Assur- group and active number,the diagonal isomorphism identification is obtained. Then,the condition is classified into three kinds,first is sequence isomorphism when Assur- group is equipped,second is symmetrical configuration isomorphism after adding Assur- group and the last one is discovered in matrix synthesis,which would be recognized and deleted by this method. Finally,the methodology proposed is able to be achieved by computer,easy to control and takes high efficiency in isomorphism identification.关键词：Adjacency matrix;Isomorphism identification;Assur-group;Kinematic link
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发布时间：2022-10-20 - 摘要：The torsional vibration testing and diagnostic technique for a RV reducer used in industrial robots under the condition of load inertia moment is described. Based on signal analysis of torsional vibration from the RV reducer,combining with the dynamics characteristics,the reason of abnormal torsional vibration of RV reducer is identified,and monitor of the dynamic performance of the RV reducer in the assembling process is realized. The research experiment shows that the technology will effectively monitor and diagnose the manufacturing defect of the RV reducer and help us to improve the products quality in the manufacturing process.
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发布时间：2022-10-20 - 摘要：Taking the involute spur gear pair as the research object,the tooth surface convection heat transfer equation is obtained based on the improved friction heat spread by centrifugal ejection model,the tooth surface heat flow equation is obtained based on finite element method and friction heat analysis,on this basis,the gear pair bulk temperature is analyzed considering axis parallelism deviation. Then,thermal- structural coupled model is established,thus gear modification amount is analyzed under axis parallelism deviation and gear pair bulk temperature. After that,the method of calculating appropriate amount of modification is obtained. The result shows that the modification amount can be affected by temperature,and axis parallelism deviation may cause different axial mesh in / mesh out interference,gear pair with axis parallelism deviation is suggested to use profile and axial modification.关键词：Gear bulk temperature;Axis parallelism deviation;Gear modification;Finite element method
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发布时间：2022-10-20 - 摘要：Considering the disadvantages of energy management multi- objectives optimization for hybrid electric vehicle（ HEV） which usually adopts weighted sum method,by using the Pareto optimum algorithm,based on non- dominated sorting method to deal with the fuel economy and emissions（ CO,NOxand HC） evaluation indexes,then a new adaptive differential evolution algorithm is proposed and simulated which can be applied to multi- objective optimization of HEV energy management. The simulation results show that,a Pareto optimal solution set can be obtained by the proposed multi- objectives optimization method. And the maximum fuel economy increases by 5. 30%,the largest CO emissions reduces by 3. 65%,in the biggest NOxfalls by 14.40%,the max HC drops down by 3.26%.关键词：Hybrid power;Multi-objective optimization;Non-dominated sorting;Adaptive differential evolution algorithm;Energy management
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发布时间：2022-10-20 - 摘要：In order to achieve high- speed,low- impact,frictionless and high- precision motion of the cam mechanism,an innovative design of a magnetically levitated cam mechanism is proposed. Based on electro- magnetic theory,a theoretical formula for computing the levitation force is deduced,which facilitates the adaptive motion control of the maglev cam system. In order to figure out the optimum design parameters to maximize the levitation force,the computer simulation is conducted by using ANSYS. The optimization design analysis and structure design of the proposed maglev cam mechanism are carried out,a basis for the future experimental study is provided.关键词：Cam mechanism;Calculation of magnetic force;Finite element electromagnetic field analysis
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发布时间：2022-10-20 - 摘要：An omnidirectional mobile platform based on powered universal wheel which avoids the weakness of Mecanum wheel is designed. The gear transmission is used in the powered universal wheel,and the rolling and steering freedom are controlled by two motors respectively. The six- wheel configuration is used in the mobile platform,two powered universal wheels located in the middle of the platform,while four assisted universal wheel located in four corners of the main body. Every universal wheel connects with the main body through the suspension structure,which made contribution to the stability of the motion. Through the method of FEA,the intensity and stiffness of the main body structure is testified. Finally,through the kinematics analysis of the mobile platform,the relationship of the input rotation speed and mobile platform motion speed is obtained. The function of omnidirectional mobility and the reasonability of wheel configuration is testified. The result of the kinematics analysis can provide a basis for motion control and offline programming of the mobile platform.关键词：Omnidirectional movement;Powered universal wheel;Kinematics analysis;Gear transmission
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发布时间：2022-10-20 - 摘要：During the practical application of EBZ- 260 type roadheader,the stopper plate and pin of sun gear on the cutting reducer of roadheader shall be worn seriously. According to the classical friction theory,the contact surface of limit pair of sun gear must be subject to the load. The load is one of crucial factors that influence the wear loss. In order to solve the wearing problem of stopper plate and pin,the software Solid Works is used to conduct accurate 3D modeling against the first- stage sun gear on cutting reducer of EBZ- 260 type roadheader,and the actual load condition is simulated. The Software Solid Works Simulation is used to conduct finite element statics analysis against the 3D model,so as to obtain the deformation of spline tooth of first- stage sun gear,which shall be brought into the calculation model to calculate the axial force suffered by the sun gear.Finally,other factors influencing the axial force are analyzed and the function expression of general axial force endured on the output end of the first- stage and second- stage sun gear is obtained,which shall be displayed in the MATLAB programming graph. Therefore,the determination of the wear loss causes of stopper plate and pin of sun gear is defined,and it shall provide accurate load data for further study on wearing problem.关键词：Roadheader;Cutting reducer;Axial force of sun gear;Calculation
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发布时间：2022-10-20 - 摘要：The concentric magnetic gear is a transmission gear with a novel structure and a promising prospect,by using the magnetic field modulation principle,the large torque transmission is realized. On the basis of concentric magnetic gear structure,the modulation magnet ring is improved,the silicon steel is added on the inside of the modulation magnet ring to constitute a mechanical bridge. The model of the improved magnetic gear is simulated by using two dimensional（2D） finite element（FE） method,and the magnetic field and electromagnetic torque are calculated. At the same time,the magnetic field and torque are compared with the common gear. The results show that improved magnetic gear magnetic field is higher than normal- type magnetic gear,lower harmonic content,and torque is also improved. It is significant for the research and application of the concentric magnetic gear.关键词：Concentric magnetic gear;Mechanical bridge;Magnetic field;Torque
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发布时间：2022-10-20 - 摘要：The inertia force and the inertia moment of the crank group mechanism are analyzed based on its characteristics. The balancing conditions of the inertia force and the inertia moment of the crank group mechanism are given and a practical balancing method is obtained. The results show that the balancing of inertia moment of the crank group can be achieved by the connecting rod with the centroid coordinates limited,when the balancing of the inertia force is achieved by adjusting the mass- radius product of the balance quality. The conclusions may be helpful for reducing the foundation vibration in the design of the crank group mechanism.关键词：Crank group mechanism;Inertia force balancing;Inertia moment balancing
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发布时间：2022-10-20 - 摘要：With life testing machine developed on our own,according to data terminated life test method without substitution,the accelerated life tests for a certain type of self- lubricating radial spherical plain bearing are carried out. The best linear unbiased estimation method is used to deal with test data,the accelerated life equations and the life distributions regularities are deduced. The results show that under the same work conditions,the highest life occurred under swivel motion,followed by tilt motion,and the shortest life occurred under combined swivel and tilt motion（ combined motion）. When the oscillation frequency is lower,the service lives are closer between swivel motion and tilt motion. When the oscillation frequency is higher,the service lives are closer between combined motion and tilt motion. The large differences exist among theoretical results and experimental results.关键词：Radial spherical plain bearing;Accelerated life test;Service life;Best linear unbiased estimation
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发布时间：2022-10-20 - 摘要：Taking the subway driving gearbox as the research object,the dynamics finite element analysis model of gear system is established including the structure sub-system and the transmission sub- system. Then the vibration response of gearbox is calculated with the help of the Newmark-β method and the structure noise test is also studied on the experimental bench of subway gearbox. On this basis,the influence of gear modification and speed on the vibration characteristic would be also studied. The result shows that the rationality of analysis method is approved by comparing computational results and experimental tests,the gear modification could effectively reduce the structure borne noise of gear transmission system,especially the structure borne noise at the excitation frequencies,the relationship between speed and structure borne noise is not a linear rule. The research result offers some academic reference for dynamic property design of subway gear system.关键词：Subway gearbox;Structural borne noise;Gear modification;Experimental study
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发布时间：2022-10-20 - 摘要：In order to research the influence of the excitation of variable speed and damping on subway gear transmission system,the subway helical gears model of the bend- torsion- axes is built,and the model considered the time- varying meshing stiffness,gear meshing error,backlash nonlinearity and torque of outside parameters during the subway working. After the dimensionless processing and normalized equation of six degree of freedom dynamics model,used the numerical analysis of the gear dynamics model is carried out by using the variable step forth order Runge- Kutta numerical integration method,the gear system dynamic response state diagram is obtained. With the help of time history diagrams,phase plots,Poincare maps and the bifurcation diagram,the system evolutionary process of periodic motions,quasi- periodic motions,bifurcation and chaotic motions with the change of the system excitation frequency and mashing damping ratio are qualitatively analyzed. The results show that subway helical gear system is more stable under the high speed and meshing damping ratio. Finally,its correctness is verified by experiments.关键词：Subway gear transmission system;Variable speed and damping;Dynamics response;Runge-Kutta
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发布时间：2022-10-20 - 摘要：In order to analyze the influence of vibration of transmission system on vehicle dynamics performance,the train drive system is simplified as a series system containing shaft segments and equivalent disc,a whole multi- body dynamics model of a high speed train and a torsional vibration model of transmission system are established,and the calculation and analysis of additional moment produced by torsional vibration is carried out. Regarding the additional moment as the main factor,through the united simulation,the dynamics characteristic of the high speed train under the traction conditions with and without the torsional vibration characteristic of the transmission system are compared and analyzed. The results show that,under traction condition,the torsional vibration of the transmission system has a large influence on the vibration acceleration of the vehicle body in the lateral and vertical direction,and less influence on the carbody longitudinal vibration. The additional torque has large influence on the longitudinal vibration of bogie frame and wheelset. Therefore,in the dynamics analysis of high speed train,taking the torsional vibration characteristics of the transmission system in consideration is more suitable to the real condition of the train operation.关键词：High speed train;Torsional vibration;Dynamics;Drive system;Additional torque
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发布时间：2022-10-20 - 摘要：The asymmetric gear with a small number of teeth has the advantages of small size,large transmission ratio and high load capacity and so on,it is more and more widely used in various fields. Under good lubrication condition,the parameter change has important influence on the performance of thermal elastohydrodynamic lubrication characteristic of asymmetric gear with a small number of teeth,and has an important influence on the transmission efficiency and service life of gear. The model of asymmetric gear with a small number of teeth is built based on the Hertz contact theory and thermal elastohydrodynamic lubrication theory. The differential dispersion of the equation set is carried out through finite difference method,and by using the Newton-Raphson method,the Reynolds equation is solved to get complete numerical solution,the distribution of oil film pressure and film thickness are obtained. For solving EHL equations by overrelaxation iterative method,the thermal elastohydrodynamic lubrication characteristics in asymmetric gear with a small number of teeth meshing line of five special points are got,the change regulation of pressure angle,variable coefficient,between the load and the speed and the oil film thickness,pressure and temperature are analyzed. The results show that the maximum temperature appeared at the meshing point,the temperature of oil film at the nodes close to the steady state of lubricating oil temperature,and the change trend of the oil film temperature and oil film pressure is conformity.关键词：Asymmetric gear;Small number of teeth;Thermal elastohydrodynamic lubrication;Overrelaxation iteration;Change regulation;Model
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发布时间：2022-10-20 - 摘要：Using the mature theory of plane mechanism and SCILAB software,according to the structure and motion parameters of power end of fracturing pump,the dynamics model is established. The numerical analysis method is employed to obtain the force and motion curve in continuous operation. Besides,it provides important calculation basis for the stiffness,strength analysis and optimization design of the main components.关键词：Fracturing pump;Dynamics;Numerical analysis
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发布时间：2022-10-20 - 摘要：The drum dryer is widely applied in various aspects. The drive system of single drum dryer with starching rollers is composed of gear drive and chain drive. The method for the parametric modeling and assembling of the single drum dryer drive system is realized with Creo 3. 0 software. The actual problems of the machine is analyzed by using motion simulation and stress simulation,and the improvement suggestion is proposed,which would have some reference meaning on the designing and optimizing of the whole machine.关键词：Creo 3.0;Drum dryer;Drive system;Motion simulation;Stress simulation
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发布时间：2022-10-20 - 摘要：The belt drive system can transfer power and motion by flexible body smoothly and reduce vibration. The belt drive system of the centrifuge as the core component for variable gravity experiment in space station is analyzed by multibody system dynamics. The virtual prototype is built by the belt discretization. The curves of displacement,velocity,acceleration,tension,contact are obtained by simulation. The research of dynamic characteristics of belt drive system can offer help for design and optimize.关键词：Belt drive;Multibody dynamics;Virtual prototype;Dynamic characteristic
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发布时间：2022-10-20 - 摘要：In order to reduce the motion unevenness of the conveyor chain,a new kind of double- pitch silent chain is proposed and used in conveyor to replace the traditional double- pitch roller chain. The main design parameters of the chain plate is given,the double- pitch silent conveyor chain system and double pitch roller conveyor chain system of the virtual prototype model are created,and the simulation comparison experiment of the motion unevenness of this two systems are carried out. The analysis results show that,under the same condition,compared with double- pitch roller chain,the tension side lateral fluctuate value,unevenness of horizontal velocity and unevenness of driven sprocket angular velocity of double- pitch silent chain are respectively reduced 24. 18%,45. 61% and 23. 13%. Therefore,it can be deduced that the double- pitch silent chain motion unevenness is smaller than double- pitch roller chain distinctly.关键词：Double-pitch silent chain;Motion unevenness;Lateral fluctuate;Horizontal velocity;Angular velocity
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发布时间：2022-10-20 - 摘要：According to the geometric characteristics of the elliptical gear,with different eccentricity ratio of ellipse,the different transmission ratio curve is got,and then the variable speed motion of pumping unit is completed. By using the Solid Works,the 3D modeling and motion simulation of the pumping unit are completed,and by using MATLAB,the digital simulation of the elliptical gear pumping unit is completed. Comparing with the suspension point velocity and acceleration between the ordinary pumping unit and the elliptical gear pumping unit,it is finally verified that the motion performance of the pumping unit is improved by using elliptical gear to the pumping unit,which reduces the vibration impact and the energy consumption.关键词：Pumping unit;Elliptical gear;Simulation;Performance analysis
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发布时间：2022-10-20 - 摘要：According to the principle of form grinding,the VERICUT software is used to simulate the machining of quadruple- arc tooth profile gear. Firstly,according to the NC gear grinding machine,the machine tool model,gear blank model is set up and on the basis of the quadruple- arc tooth profile gear form grinding wheel cross- sectional shape,grinding wheel model is established,with reference to the machine tool structure and form grinding motion,NC simulation program is written. Finally,in VERICUT software,the NC simulative machining of quadruple- arc gear is carried on and the simulation results are analyzed. The analysis results show that the simulation process can meet the design requirements,and the numerical control program is correct.关键词：Quadruple-arc gear;Form grinding;VERICUT;Machining simulation
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发布时间：2022-10-20 - 摘要：The test research of bending fatigue strength of 38 Si Mn Mo through hardened gear is carried out by using the STRONl603 electromagnetic resonance fatigue testing machine and double teeth pulsating loading method. The grouped test method is used in the short life. The elevation and subsidence method is used in the long life,the bending fatigue life of the gear is obtained. The Monte- Carlo simulation is used to calculate ranks. On the basis of test data,the Weibull parameters and complete S- N curve are worked out according to the principle of statistic. The bending fatigue curve with the designated confidence and reliability is obtained.Then basic data for gear design is provided for the gear material.
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发布时间：2022-10-20 - 摘要：The spherical roller bearings are widely applied in industrial gearbox,therefore the research of the running character of spherical roller bearings in gearbox is important for the designer. Comparing to the cylindrical roller bearing and tapered roller bearing with same envelop dimension,spherical roller bearing has higher basic dynamic load carrying capacity and compensation of angular misalignment,but the modified rating lifetime calculated by using Bearinx is smaller,the contact pressure of roller is higher. The simulation of the running characters of spherical roller bearing is carried out by using program Caba 3D,it could be found that there are big difference of rotating speeds between both rows of cages,as well as both rows of rollers,while the load is changed,the cages and rollers would be subjected to additional shock loads because of the change of running character.
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发布时间：2022-10-20 - 摘要：The roller pushing mechanism has the advantages of simple structure,small size,pushing the material accurately,etc. It can be used in moving space is limited,where the robot is not easy to operate. The past and now known or unknown the information of position accuracy of roller pushing mechanism is regarded as a grey system. The regular testing error value of position accuracy of chain head is constituted as an original data series at equal intervals. The mathematical model of gray system is established. Monotonically increasing time data sequence is obtained by accumulating generating calculation. The albino form of differential equations of grey system GM（ 1,1） is established. Then the calculation accuracy is improved by correcting of residual model. The corrected GM（ 1,1） model is used to predict the life of the positional accuracy of the roller pushing mechanism.关键词：Roller pushing mechanism;Positional accuracy;Life;Grey system;Grey prediction;Wear;Calculation accuracy
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发布时间：2022-10-20 - 摘要：The ancient south- pointing carriage is commonly regarded as the Chinese forerunner of automatic machinery in China,it has a more prominent status in the process of mechanical development. Based on the orientation principle of south- pointing carriage,a new differential gear train orientation mechanism is designed by using seven bevel gears. Furthermore,the model of south- pointing carriage is manufactured according to this structure design. The physical mode and relevant test confirmed the orientation function of this mechanism,and it is pointed that the transmission structure of this mechanism is simple and reliable. So the orientation mechanism can provide some technical reference for the selection of orientation system.关键词：Differential gear train;South-pointing carriage;Orientation mechanism;Bevel gear
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发布时间：2022-10-20 - 摘要：Based on the structure of gear- ball screw and piston,a buoyancy adjustment device is designed and driven by miniature dc- motor. Its structure and working principle are analyzed,and the relevant formulas of the mechanics are presented. The driving force is generated by miniature dc- motor and the ball nut linear motion is driven by the gear- ball screw transmission system. Because the ball nut and piston are connected by the piston cover,and then the hydraulic oil can be absorbed and injected by piston from hydraulic cylinder to oil bladder. The device is characterized with compact structure,easy control,precise movement and adjustment and etc. It can be combined with ocean sensors in a specific scope in order to realize the real- time collection of profiling ocean data.关键词：Gear;Ball screw;Buoyancy adjustment;Profile collection
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发布时间：2022-10-20 - 摘要：The redundant manipulator can use redundant degree of freedom to avoid obstacles,but it does not affect the operation of the end effecter. So comparing with general non- redundant manipulator,the redundant manipulator has obvious advantages for dealing with obstacle avoidance. Recently,the space trajectory planning research of redundant manipulator has not yet formed a set of overall framework. It is necessary to analysis and in- depth summary the existing research results of system. The space trajectory planning of redundant manipulator basic theory and practical application are discussed. According to the different modeling principle,it is divided into five categories. The advantages and disadvantages of these methods are Summed up in detail and redundant manipulator trajectory planning conception and the future development trend are prospected.关键词：Manipulator;Redundant;Trajectory planning;Obstacle avoidance
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发布时间：2022-10-20 - 摘要：The Giant magnetostrictive materials（GMM） have some distinct advantages such as large magnetostrictive coefficient,fast dynamic response,and high electromechanical conversion efficiency,which can be used into power conversion among electric,magnetic,mechanics and heat,etc. Based on multi- field coupling theory,a brief description about the characteristics of GMM is given,comparing with the piezoelectric ceramic material,and the relationships between these characteristics and magnetic field intensity,temperature,frequency is stated. Then,various mathematical models with different features are stressed,along with the multi- field coupling effect. Meanwhile,the foreign and domestic researches and applications of GMM are introduced,including the operation principle,structure and basic performance of GMM devices. Finally,the development of GMM in the future is discussed.关键词：Giant magnetostrictive material;Multi-field coupling;Mathematical modeling
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发布时间：2022-10-20
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