最新刊期
期 4 ， 2017
- 摘要：Whether practical tooth profile of real-time zero-clearance steel ball precision transmission is topcut directly affects its transmission performance. Based on the envelope method,the tooth profile topcut issue of real-time zero-clearance steel ball precision transmission is indepth study. The non-topcut conditions of the practical tooth profile on epicycloid groove and hypocycloid groove are obtained by analysis under the conditions that the basic design parameters are given,cutting tool maximum feeding（ i. e. maximum groove depth）that all tooth surfaces do not appear topcut when machining epicycloid groove and hypocycloid groove is obtained. Then,the conclusion is verified by the computer graphic simulation. According to the above analysis results,for ensuring the steel ball and the tooth surface can be properly mesh,the inequality equation that the steel ball radius should be satisfied is derived,the relationship between steel ball radius and parameters is analyzed,the results show that steel ball radius increases with the increase of occurrence circle radius,with decrease of the short amplitude coefficient,and occurrence circle is larger,short amplitude coefficient is smaller,the steel ball size range is more widely. The results of research offer a theoretical gist for designing and manufacturing of real-time zero-clearance steel ball precision transmission.关键词：Envelope method;Precision transmission;Practical tooth profile;Topcut;Meshing steel ball
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发布时间：2022-10-20 - 摘要：Because of the optimal design of ploy-rib belt plays an important role in improving the performance of the car,obtaining and analyzing ploy-rib belt motion information is becoming the hotspot studied by researchers. For the shortage that the poly-rib belt need be simplify existed in the dynamic modeling and simulation,the digital image processing techniques are adopted to obtain the dynamic information of engine ploy-rib belt. Firstly,a camera is applied in tracking and recording the artificial marking signs on the ploy-rib belt. Secondly,the location information of the making signs is acquired by digital image processing techniques. At last,the marking signs that have become several kinds of typically deformable are recognized by using the this algorithm and Hough transform detection method,then comparing the errors between the two methods and analyzing correlation of the dynamic data which is obtained by the experiment and the laser rangefinder. The experiment results show that the dynamic information on engine ploy-rib belt can be obtained precisely by using the proposed method.关键词：Poly-rib belt;Digital image processing;Artificial marking sign
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发布时间：2022-10-20 - 摘要：The Local Characteristic-scale Decomposition（ LCD） and the Local Mean Decomposition（ LMD） are two kinds of effective adaptive time-frequency analysis methods which widely used in the field of rotating machinery fault diagnosis. In order to compare the difference of calculation process and the performance of them,aiming at the acquiring of mean curve and decomposition termination conditions,the comparative research are carried out. The deficiencies of LMD in the mean point definition,interpolation method and pure frequency modulation standards are pointed out. Through the simulation signal and the bearing inner ring fault vibration signal analysis,the superiority of LCD is verified,but the part of the mind of LMD can also provide reference for the LCD.关键词：Local characteristic-scale decomposition;Local mean decomposition;Mean point;Mean carve;Interpolation
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发布时间：2022-10-20 - 摘要：The radius of curvature of the cam profile is an important parameter,which directly reflects the degree and shape characteristics of the cam profile. It plays an important role in the analysis and design of the cam mechanism. A simple and effective method is proposed to solve the value of radius of curvature by taking the idea of "discrete-limit". The advantage of the new method which is more simple and direct,doesn’t need the complicated analytical derivation. The correctness of the new method is checked and proved through an example. The above research results enrich and deepen an understanding and awareness of the disc cam mechanism,which has important reference values and guiding significance to expand the radius of curvature of the solution.关键词：Cam profile;Radius of curvature;Disc cam;Idea of discrete-limit
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发布时间：2022-10-20 - 摘要：A projection image analysis method for the fault diagnosis of rolling bearing based on Intrinsic Mode Function（ IMF） is proposed,the status recognition and the degree of recognition of the rolling bearing fault is realized. The main contents are as follow. Firstly,the Empirical Mode Decomposition method（ EMD）is used to obtain IMF. Secondly,the time-frequency three-dimensional gray-scale projection image of each IMF is established. The texture feature of Gray Level Co-occurrence Matrix（ GLCM） is also introduced to analyze the three-dimensional projection image. Finally,the feature dimension is compressed and combined based on the principal component analysis. The Support Vector Machine（ SVM） is used to realize the fault diagnosis of rolling bearing. Both fault diagnosis and degree identification of rolling bearing is realized through a perspective of image characteristics. A new method based on projection image of characteristics calculation in vibration signal is given in this study.关键词：Fault diagnosis;Gray level co-occurrence matrix;Empirical mode decomposition;Projected image
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发布时间：2022-10-20 - 摘要：The elastic torsional deformation of the transmission parts in the precision transmission system will lead to the mechanical resonance,it has a great impact on the dynamic performance and even lead to the instability and failure of precision transmission components. The precision AC servo drive system with high precision and small teeth difference reducer is built,and the dynamics model of the precision transmission system is established. Due to the problems of multiple parameters and complicated calculations,a multi-parameter sensitivity analysis method is introduced that is based on rotational inertia,stiffness coefficient,transmission ratio and transmission error. A theoretical reference for the design of precision transmission system can be provided by this method.关键词：Precision transmission;Servo drive;Mechanical resonance;Sensitivity
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发布时间：2022-10-20 - 摘要：The helicopter transmission system is taken as the research object,transmission scheme was conducted exhaustively and filtered to generate the transmission system principle solutions automatically. The transmission units are extracted based on existed helicopter transmission data,the corresponding graph models are established and transformed to mathematical language for computer processing. Based on rule-based reasoning,the helicopter transmission system principle solutions are achieved automatically by two steps,generated graph models of the transmission schemes and generated label information of the graph models. Several rules are developed to filter those schemes,the schemes are listed after filtering in the end.关键词：Helicopter transmission system;Graph theory;Auto configuration;Innovative design;Rule
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发布时间：2022-10-20 - 摘要：In order to reduce the gear meshing impact,the method about how to determinate the three factors of gear modification is studied and the optimization of modification curve is discussed. The 3D meshing model of standard involute gear is set up,the finite element contact analysis is carried out. Regarding the integrated elastic deformation of the meshing tooth as the modification value of the gear pair,the contact stress analysis results between long-distance modification and short-distance modification are compared,it is found that the short-distance modification has a better effect. The quadric curve and the sine curve have their virtues and their faults,so combining them into a new curve and the modification effect and feature are discussed. Research shows that,the sudden change of stress with a lower impaction of tooth mesh in and out is eliminated by the new modification method. A new modification curve is provided for involute gear.关键词：Finite element;Involute gear;Tooth profile modification;Combined curve;Value of β
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发布时间：2022-10-20 - 摘要：With a power-split hybrid electric vehicle（ HEV） as the research object,the characteristic parameters of the planetary gear in the coupling mechanism and the main reduction ratio are optimized on the basis of double objective function for performance economic and dynamic. The hybrid vehicle model is established by the vehicle simulation software AVL/Cruise and the control strategy is designed by MATLAB/Simulink,combing with the optimization software Isight,the optimization model is created. The non-dominated sorting genetic algorithm is applied to optimize the characteristic parameters of the planetary gear and main reduction ratio. The maximum vehicle speed is the dynamic objective and the economic objective is the fuel consumption performance. Compared the result of simulation in different parameters indicate that the equivalent fuel consumption per hundred kilometers of HEV decreased by 10% after optimization in the condition of strategy and vehicle dynamic requirement both unchanged.关键词：Power-split HEV;Parameter optimization;Multi objective optimization;NSGA-Ⅱ genetic algorithm
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发布时间：2022-10-20 - 摘要：A new kind of the discrete involute spherical gear transmission mechanism is presented,this gear transmission mechanism can realize the transmission of the pitch motion,partial pendulum movement and rotary motion in the space and avoid the transmission principle error of the existing discrete spherical gear. By using the ANSYS simulation software,the tooth surface contact characteristic analysis of the discrete involute spherical gear with dividing circle diameter is 512 mm under different meshing states is carried out. It is found that,the tooth surface contact area of the discrete involute spherical gear transmission is inversely proportional with the change of meshing angle under the condition of fixed torque. And along with the meshing angle increases,the maximum contact stress action point will move toward the tip,and the maximum contact stress will increase（ up to 2. 059 3 × 106MPa）. Through studying the transmission characteristics of this kind of gear,the basis of application for the study of spatial mechanism and mechanical arm is provided.关键词：Discrete involute spherical gear;Tooth surface contact;Meshing angle;Contact stress
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发布时间：2022-10-20 - 摘要：Based on the data obtained from the three-coordinate measuring and pre-processing,a NURBS method to reconstruct the complex surface of non-circular bevel gear and a two-step matching method to implement the complex surface error evaluation is proposed. The curve and surface reconstruction of the teeth surface is carried out by NURBS interpolation,and the least square approximation is adopted to gain the model of the reconstruction surface. Integrating ICP and BFGS algorithm,an error evaluation model is built,and the measuring data is initially matched and precisely matched to the design model. The model is solved by MATLAB programming,the Euclid transformation matrix is gotten and then the surface profile error of the gear can be achieved. Finally,the obtained error is 0. 053 22 mm,which meets the requirements of gear design. The calculating results show that this method has high accuracy and speed to reconstruct the surface and can solve the error evaluation problem for the complicated surface.关键词：Variable ratio differential;Non-circular bevel gear;NURBS interpolation;Least square approximation;Initial matching;Precise matching
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发布时间：2022-10-20 - 摘要：According to the structure characteristics of heavy locomotive traction gear transmission device,the finite element parameterized model of traction gear is established containing shafting structures considering three locomotive working conditions including starting,sustain,and rapid operation. A new type of three circular arc tooth surface modification scheme with three circular arcs is designed on the basis of the different gear meshing position,load distribution and deformation characteristics of the three different conditions. By the comparison analysis and experimental verification,the tooth contact state and load distribution of the gear by using three arcs profile modification curve is better than the gear with commonly used single arc drum gear tooth modification.关键词：Locomotive traction gear;Tooth modification;Finite element analysis
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发布时间：2022-10-20 - 摘要：The contact stress in different meshing point is not the same of double circular arc gear due to its different teeth numbers,tooth width and tooth bending deformation. A meshing point contact force mathematical model of double circular arc gear is established,the gear tooth bend stiffness is calculated according to mechanics of materials and the theory of elasticity. The numerical example is calculated to obtain the contact force in different meshing point of double circular arc gear of different tooth number,modulus and contact ratio.The basis for the tooth profile modification and improving the gear load capacity of double circular arc gear is provided by the research result.关键词：Double circular arc gear;Bend stiffness;Tooth profile modification;Contact force
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发布时间：2022-10-20 - 摘要：Taking designed labyrinth seal of a high speed EMU gearbox as the research object. The numerical simulation of the internal flow field of labyrinth seal is carried out by using the Fluent software,the pressure,speed,velocity vector and turbulence distribution cloud of the internal flow field of the labyrinth seal are obtained. The sealing mechanism and process of the gearbox labyrinth seal is analyzed. The results show that the fluid flows through the sealing gap when the pressure is reduced,the pressure is reduced very little.When the fluid flows out of the sealing gap into the cavity is the pressure equalizing process. After entering the cavity,the turbulivity of the cavity is the largest and the pressure is the smallest. As the distance from the center of the cavity increases,the speed increases and the pressure increases. The distribution characteristics of the flow field in the labyrinth seal under different pressure ratios are analyzed,which indicated that the leakage increases with the increase of the inlet/outlet pressure ratio,and the pressure ratio is not linearly related to the leakage. The simulation results can be used as reference for the design of gearbox labyrinth seal.关键词：High-speed EMU;Labyrinth seal;Fluent;Numerical simulation
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发布时间：2022-10-20 - 摘要：The flexure hinge is the most basic compliant structure,the compliance is the most important performance parameter. The combined compliance method is proposed fully based upon the structure characteristic of the flexure hinge. The structure characteristics of the right circle,corner filleted and elliptical flexure hinge are fully analyzed,half of the flexure hinge is selected as the research object and the reasonable integral variable is set,the compliance formulas for calculating the half of the flexure hinge are obtained. By combining the different kinds of the half flexure hinge,the combined compliance formulas for calculating the compliance of the 12 kinds flexure hinges are obtained. The compliance of the right circle flexure hinge,right circle elliptical hybrid flexure hinge and right circle corner filled half hybrid flexure hinge are calculated and analyzed with the combined compliance formulas,literatures and the finite element method. By contrasting the calculation results,the correctness and validity of the combined compliance method are verified.关键词：Variable cross section flexure hinge;Structure characteristic;Combined compliance;Verification
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发布时间：2022-10-20 - 摘要：The transient dynamics analysis of the new driving drum is carried out by using ANSYS,its maximum equivalent stress cloud pictures and maximum principal stress time history in different work conditions are obtained. The rain-flow counting,the load extrapolation and superposition of the maximum equivalent stress time history of the dangerous area of the driving drum are carried out by using Rainflow module in n Code Glyph Works. Based on the relative theory of fatigue life prediction,stress life module is used to analyze the fatigue life and fatigue sensitivity of the driving drum. The damage histogram of the driving drum and the minimum fatigue life curves of the driving drum under the different inputted parameters are obtained. The results show that the driving drum has a good mechanical property,the minimum fatigue life of the driving drum is about 783 days to meet use requirements. The overload and residual stress have obvious influence on the fatigue life of the driving drum.关键词：Driving drum;Load spectrum;Fatigue life;Fatigue sensitivity
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发布时间：2022-10-20 - 摘要：Taking the spur gears as example,the transient finite element model of friction heating of gear meshing is established based on the thermal-solid coupling method under the framework of LS-DYNA. By comparing with the theoretical results,the validity of the model is verified,and the friction heating of gear meshing is calculated by concerning the thermal conductivity,and the results shown differences with the theoretical calculation. The research could be used to the heat source calculating in the analysis of gear temperature field.关键词：Gear scuffing;Thermal-solid coupling;Transient simulation
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发布时间：2022-10-20 - 摘要：According to the function and demand of large caliber mortars for automatic loading system,a kind of toothed chain rotary magazine and the front and back limiter are designed,it can store and protect mortar shells. Because of the chain transmission polygon effects have an influence on the stability of the magazine rotary,the virtual prototype model is built by ADAMS. the elastic precision under the extreme conditions is showed,the analysis results are meet the initial design and the standard requirements,it has a certain theoretical significance to the research and analysis of the magazine structure.关键词：Mortar;Toothed chain;Magazine;Dynamics
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发布时间：2022-10-20 - 摘要：Aiming at a single degree of freedom geared linkage traffic cone recovery manipulator,based on the kinematics analysis,the influence of parameters,likes link size and transmission ratio on the end actuator velocity and trajectory of recovery manipulator is researched. Considering reducing occupation space,main arm rotation angle and peak horizontal acceleration as the optimization targets,the mathematical model is established. By using MATLAB,the main arm rotation angle,main arm,deputy arm horizontal angle and gear transmission ratio are optimized. According to the design parameters before and after optimization,the dynamics simulation verification of the recycling manipulator is carried out by ADAMS. The result shows that,the optimization of the size of recovery manipulator is reduced by 10. 3%,main arm rotation angle decreased by 13. 6%,the peak horizontal acceleration is reduced by 19. 8%.关键词：Traffic cone recycling manipulator;Parameter optimization;Motion trail;Simulation analysis
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发布时间：2022-10-20 - 摘要：Aiming at the frequent lubrication accidents of the high-speed train gearbox,the theoretical calculation of required volume of the gearbox lubrication oil is carried out. The effective volume of gearbox lubrication oil on the specific immersion depth is also calculated by the Fluent. The flow field of the gearbox is optimized,and the effective volume of the gearbox lubrication oil is increased,and the factors affecting on the effective volume of the gearbox lubrication oil are determined. The theoretical calculation of the changing situation of stirring oil loss and the thermal equilibrium temperature of gearbox with the speed under different immersion depths is carried out. The analysis shows that the gearbox structure resistance reduced the effective volume of lubrication oil. The effective volume of lubrication oil and the churning losses of the gearbox increases with the immersion depth increases. The thermal balance temperature rises with the immersion depth increases or speed increases.关键词：Fluent;Effective volume of lubrication oil;Immersion depth;Thermal balance temperature
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发布时间：2022-10-20 - 摘要：Taking the single-stage gear rotor system as the research object,a generalized finite element model with total freedom is established. The calculation speed and the accuracy of Newmark method and Fourier series method are compared in solving dynamics equation of gear system. An improved Fourier series method is proposed,which has less calculation time and higher calculation accuracy.关键词：Gear;System dynamics;Error;Fourier series method;Newmark method
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发布时间：2022-10-20 - 摘要：The transition arc radius has an important influence on the root stress and root stress is an important influencing factor on the tooth root fatigue crack propagation,so that it is necessary to study the influence of transition arc radius on the tooth root crack propagation. Three kinds of spur gears with different transition arc radius are established and assume the root initial crack with same length in the same position,researching the tooth root crack propagation based on ABAQUS. The results indicate that,the root cracks with different transition arc radius have the same propagation trend,but larger transition arc radius with more extended to the deep crack direction gear rim in the early stage,larger transition arc radius with more extends to the top of the tooth in the later period. The transition radius has little influence on the critical crack length. Under the same crack length,the larger the transition radius with the smaller the Mises stress at the crack tip and the smaller the crack growth rate,the gear has the longer residual life.关键词：Gear;Transition arc radius;Crack propagation;ABAQUS
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发布时间：2022-10-20 - 摘要：Taking a RV cycloid planetary reducer used in the excavator as study object. The contact stress theory is adapted to analyze the fatigue strength between the flank of cycloids and pins. The analysis result indicates that the fatigue damage is easy to appear in the root of the cycloid gear. The finite element method is used to quantitative strain and stress analysis between cycloids and pins. The result is consistent to theoretical analysis. The maximum stress is 735. 65 MPa,which is less than the material minimum allowable contact stress.The maximum strain appears at the bearing hole of support crankshaft of the cycloid. Consider that the cycloids and pins are made of GCr15. The analysis of contact fatigue S-N curve of the material GCr15 indicates that there is no contact fatigue failure in the meshing process of the cycloid-pin reducer mechanism.关键词：RV planetary reducer;Fatigue life;Contact stress
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发布时间：2022-10-20 - 摘要：Driving drum as the main driving equipment components of pipe belt conveyor,the traditional empirical formula and bigger safety coefficient method is used to design the structure. In the process of actual operation,the driving drum is influenced by the bending moment and torque coupling effect and dynamic load caused by imbalance. Therefore,the driving drum surface and support bearing are easily damaged. Taking existing same thickness cylindrical,drum type,concave type,three different models drive drum structure as examples,the stress analysis of driving drum is studied,the finite element model is established,the stress distribution and deformation law of the three type structures is obtained and the result is that when the maximum amount of concave is 7% of the diameter,the maximum stress decreased 63% and the maximum deformation decreased 76% comparing with common cylinder. Taking the concave type as an example to analyze dynamic characteristic,critical speed and modal vibration mode are studied. When the unbalance appear in the middle,vibration response and bearing load increases exponentially along with the speed change. The results provide guidance for transmission drum structure design and balance control.关键词：Driving drum;Finite element model;Mechanics characteristic;Stress and strain;Unbalance response
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发布时间：2022-10-20 - 摘要：The model of diesel gear transmission system（ crank,crank gear,the intermediate gear,camshaft gear and camshaft） in an inline six-cylinder diesel engine is established to study. The multi-body dynamics simulation software ADAMS is used to simulate the frequency change of camshaft gear in normal and the fault of broken teeth,camshaft axial moving and intermediate gear radial vibration. Then the results are compared with the experimental data of gear broken tooth of diesel engine and comparison result shows that,when camshaft gear break tooth,each order frequency will increase,especially the fundamental frequency,three frequency multiplication,and four frequency multiplication. The phenomenon is identical with the actual failure case. When camshaft axial moving and intermediate gear radial vibration,each order frequency will increase significantly,especially the fundamental frequency,three frequency multiplication,and four frequency multiplication. Therefore,both cases may have resulted gear does not run smoothly,resulting in broken teeth failure.关键词：Diesel engine;Gear transmission;Gear broken;Radial vibration;Dynamics simulation
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发布时间：2022-10-20 - 摘要：The gearbox is a pivotal component in wind turbine,the dynamics performance of gearbox is one of the most critical factors determining the lifetime of gearbox and that of the wind turbine. A multi-body dynamics drivetrain model with rigid-flexible body coupled of a level MW wind turbine is built by using the Simpack software. The reliability and accuracy of this model is confirmed through comparing the nature frequency derived from Simpack drivetrain model and the nature frequency calculated by Bladed software and traditional approach. The modal analysis and torsional resonance analysis of gearbox is completed based on the multi-body dynamics simulation both in frequency domain and time domain,furthermore,the potential resonance is evaluated,the influence of shaft misalignment on the dynamics performance of gearbox is analyzed. The aforementioned analysis approach and evaluation method is confirmed to be correct by experimental.关键词：Drivetrain;Wind turbine gearbox;Resonance analysis;Shaft misalignment
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发布时间：2022-10-20 - 摘要：In order to research the wear-resistant performance of steel planar worm gear,a kind of pin disc sample suitable for instantaneous line contact sliding friction is designed,the antifriction and wear-resistant performance of several typical oil is contrasted and analyzed. The correlation experimental analysis of the microscopic meshing parameter and sliding friction coefficient is carried out,the influence of load and sliding speed on the friction coefficient of transmission is quantitatively researched. The result shows that the tribology system of every point on teeth of planar worm gear pairs can be simulated successfully by line contact sliding friction test. The antifriction and wear-resistant performances of vehicle gear oil GL-5 is better,the friction coefficient decreases with the induced normal curvature radius and lubrication angle increasing. A favorable basis for the parameter selection and optimization design of steel planar worm gear is provided by the test.关键词：Steel worm drive;Pin disc test;Antifriction and wear-resistant performance;Line contact
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发布时间：2022-10-20 - 摘要：Taking a locomotive traction transmission system as research object,the relatively complete transmission system model is built considering shaft deformation,flexible body,motor and wheel rail friction factors. From the static,modal analysis and dynamics analysis of the model,finding the causes of noise and vibration are the transmission error and the partial load in gear meshing process,which lead to large meshing impact. Using the Monte Carlo method for tooth shape optimization to reduce the transmission error,the best plan is obtained,achieving the transmission error reduced by 73% and the partial load phenomenon has improved greatly.关键词：Gear transmission system;Dynamics characteristic;Modal analysis;Romax
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发布时间：2022-10-20 - 摘要：A new type of hydro-mechanical transmission system is designed aiming at promoting the efficiency of traditional torque converter. The traditional torque converter lacks of transmission efficiency,which is pointed out by simply introducing basic structure and theory. To solve this problem,a new kind of compound transmission system is proposed. A mechanical device is added to the traditional one,which can make torque converter always work at high efficiency condition,and hydraulic machine transfer power while the whole system is on the condition of power dividing. Finally,the efficiency variances between prototype experiment and traditional device shows this transmission system is able to promote efficiency,which provides the basis of putting this device into production.关键词：Torque converter;Compound transmission system;Power dividing;Experiment
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发布时间：2022-10-20 - 摘要：In order to research the shiftability of a transmission synchronizer,the synchronizer model,shifting control mechanism model and shifting robot model are built by adopting Simulation X integrated ADAMS,ABAQUS and CATIA based on shifting control and test specification of synchronous durability test bench,two kinds of shifting process conditions of 1-2 upshift and 2-1 downshift are simulated,so the shifting force,shifting displacement and input shaft speed are obtained. The simulation data are compared with test data,the analysis results show that they are basically identical,the difference is that the simulation shifting time is slightly ahead of the bench test time,the feasibility and accuracy of simulation results are verified.关键词：Synchronous durability test bench;Synchronizer model;Shifting control mechanism;Shifting force;Simulation
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发布时间：2022-10-20 - 摘要：The performance of vehicle transmission system has great influence on fuel consumption of the vehicle. In order to reduce the resistance of transmission system and the fuel consumption,a research experimental about resistance for front engine front drive（ FF） transmission system is carried out on the four-drive and five-motor bench. The experimental results show,the resistance of the vehicle is positive correlated with gear level and engine speed. And the largest resistant part of vehicle transmission system is the gearbox. Then,the efficiency experiment is carried out on the lubricating oil that has influence on transmission system efficiency,and the gearbox efficiency under the condition of four different kinds of lubricating oil is compared,it is found that the optimized lubricating oil is 2#. Through the experiment,it is concluded that the comprehensive efficiency of this oil is increased by 0. 43% comparing to original oil.关键词：Front engine front drive;Transmission system;Resistance;Gearbox;Lubricating oil;Optimization
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发布时间：2022-10-20 - 摘要：Against the phenomenon that oil leakage at joint of one longitudinal transmission is fed back from market,firstly,the finite element method is applied to analyze the static gap of joint surface of housing.Secondly,considering the working conditions of first gear and reverse gear,the dynamic gap of the joint surface of housing is analyzed,and a surface pressure test against the housing is carried out,the correctness of theoretical analysis is verified,meanwhile it is found that the oil leakage is caused by the quality of the joint surface of the housing. At last,simulating the reality of transmission producing,the joint surface is coated with sealant before making a surface pressure test which shows that the joint surface has uniform pressure and reliable seal,and the theory design is proved to be free of problems,a reference for the study of the tightness of transmission housing joint surface is provided.关键词：Transmission;Joint surface;FEM;Surface pressure
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发布时间：2022-10-20 - 摘要：The roller is an important component for the belt conveyor. The function of roller is supporting conveyor belt,to ensure the belt conveyor smooth operation. Aiming at overcoming the difficulties from the traditional roller with mechanical bearings frictional wear,which suffers from large rotational resistance,limited belt speed,high energy consumption. A new type of magnetic levitation roller is designed,which is supported by permanent magnetic bearing（ PMB）,but the axial force is restrained by mechanical force. The analysis formulas of PMB’s loading capacity,torque and stiffness are established based on the equivalent magnetic charge method. The parameters of magnet levitation roller are optimized by using MATLAB. By comparing with the finite element numerical method,the rationality of the permanent magnetic bearing designed by using equivalent magnetic charge method is verified. The test results of rotational resistance show that,the friction and running resistance can be effectively reduced by the proposed magnet levitation roller.关键词：Magnetic levitation roller;Belt conveyor;Permanent magnetic bearing;Equivalent magnetic charge method;Rotational resistance
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发布时间：2022-10-20 - 摘要：A structure scheme for a novel 6-DOF hybrid machine tool（ HMT） is proposed. In this scheme,a novel 4-PRP redundantly actuated parallel mechanism is proposed as the position module,which can realize three motion,with assistance of the 3-UPS&PU parallel mechanism,6-DOF machining can be realized. Firstly,the three-dimensional translations and three-dimensional rotations motion of this machine tool are analyzed based on screw theory. Then,the inverse displacement analysis model is provided by using analytical methods and the geometric relation of the mechanism. And the first-order influence coefficient matrix-Jacobian matrix and the second order influence coefficient matrix-Hessian matrix and complete kinematics model are established by using the influence coefficient method. At last,the position inverse solution is obtained by using MATLAB and the results simulation verification is carried out by using ADAMS,which verify that the correctness of the inverse displacement analysis model and the realizability of the mechanism.关键词：Redundantly actuated;Hybrid machine tool;Screw theory;Kinematic influence coefficient;Kinematics model
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发布时间：2022-10-20 - 摘要：A new kind of orthogonal 3-DOF 3-CPR parallel mechanism which can realize three-dimensional translation is proposed. The virtual prototype of 3-CPR mechanism is established,and the kinematics simulation experiment is carried out by using ADAMS software. The experiment shows the mechanism has good kinematics performance. The workspace of the mechanism is solved by using search method. The workspace volume of the mechanism is optimized by using genetic algorithm. The size parameters of the mechanism are obtained when the workspace volume takes the maximum value. The 3-CPR parallel mechanism has the advantages of simple structure,high stiffness,large output force,large workspace,and so on,because of using the prismatic pairs as the driving pairs. The results of the workspace optimization have important reference value for the application of the mechanism.关键词：Parallel mechanism;Workspace;Parameter optimization;Genetic algorithm
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发布时间：2022-10-20 - 摘要：In the process of road test of the large tonnage drive axle,an abnormal wear failure occurred between the yoke of steering driving axle and the universal drive shaft assembly. The lacking stiffness of axle housing assembly causes the failure after finite element analysis（ FEA）. So the axle housing assembly needs to be improved. The stiffness of improved axle housing assembly meets the design requirements based on FEA.But when loading to maximum,the safety coefficient of axle housing assembly is small. After comparing the FEA results with the test bench results of improved axle housing assembly,the FEA results are near to the test bench results by removing the influence of human and system deviation.关键词：Steering drive axle;Axle housing assembly;FEA;Bench test
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发布时间：2022-10-20 - 摘要：A gearbox which is developed independently and used for 200 km/h passenger locomotive is introduced. The analysis of gear and box is carried out respectively by the CAD and finite element analysis,and the high reliability of the gearbox is confirmed. The gear blanks are forged from 18 CrNiMo7-6 alloy steel which is electroslag remelted. In order to ensure the reliability and smoothness during the gear meshing,the carburizing,quenching,shot peening and profile correction are added in the process of gear forming. The material of the gearbox is adopted aluminum alloy instead of the ductile iron,not only meet the requirements of lightweight design,but also contribute to the cooling of the gearbox. During the type test,the gear box running smoothly,the temperature rise of the bearings is also meeting the requirement.关键词：Gearbox for locomotive aluminum alloy;Lightweight design;Type test
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- 156
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发布时间：2022-10-20 - 摘要：Considering the difficulty of extracting fault features of rolling element bearings,a fault diagnosis method for rolling element bearings under variable speed conditions based on angular domain empirical wavelet transform（ EWT） is proposed. Firstly,original rolling element bearing vibration signal is re-sampled with even-angular sampling so that the non-stationary signal in time-domain could be transformed into a stationary one in angular-domain. Then,the stationary signal is decomposed adaptively into some empirical mode components by using the empirical wavelet transform（ EWT）. Finally,the envelope spectrum analysis is carried on the empirical mode component that kurtosis value is maximum to extract the order ratio fault features. In order to promote the decomposition efficiency of EWT,the spectrum segmentation of EWT is improved. The rolling element bearing experimental signal analysis results show that the proposed method can effectively inhibit the influence of noise,other interference factors and extract the order ratio fault features accurately,it provides an effective method for rollering bearing fault diagnosis under variable speed.关键词：Variable speed;Rolling element bearing;Fault diagnosis;Angular domain empirical wavelet transform
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发布时间：2022-10-20 - 摘要：Taking the automatic rotating table in automatic welding process as research background,the virtual prototype of the key transmission parts geneva mechanism in workbench is established by using the three-dimensional modeling software platform,aiming at the weaknesses of traditional mechanism and combining with the motion simulation data,the design method of new geneva mechanism is put forward,and flexible body virtual prototype the new geneva mechanism is re-established. By the finite element analysis,the rationality of the design is verified. A theoretical basis for the design manufacturing and engineering application high precision automatic rotating workbench is provided.关键词：Virtual prototype;Rotating workbench;Geneva mechanism;Motion simulation;Finite element analysis
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- 93
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发布时间：2022-10-20 - 摘要：Taking the QT400-18 L low temperature ductile iron gear box used for locomotive as example,through the control of the element content of the material,the graphite spheroidization is more fully. At the same time,the samples are heat treated to ensure the stability of mechanical property. In the casting process,the casting process is improved to reduce the casting defects and to ensure the surface quality of the products.关键词：Locomotive gearbox;Low temperature ductile iron;Foundry technology
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发布时间：2022-10-20 - 摘要：In order to enhance the movement stability of pharmaceutical cartoning machine and reduce noise,the motion law of cam is improved. The B-spline function motion law is used to replace the original sine acceleration motion law. At the same time,a pharmaceutical cartoning machine cam parameterized software is also developed based on the B-spline function motion law. The problem of the existing in cam parameterized software that can not add more constrained motion control condition is solved and the pharmaceutical cartoning machine cam parameterized software is more practical valuable and universal applicability. Through the experimental verification,after improving the motion law of cam,the noise is decreased obviously in the actual operation. And the products packing quality of cartoning machine is improved obviously. It provides reference to improve this kind of similar cylindrical cam mechanism device.关键词：Cam;Pharmaceutical cartoning machine;B-spline curve;Parameterized design
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发布时间：2022-10-20
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