最新刊期
期 5 ， 2016
- 摘要：The power three- branching transmission system is constituted by the power double- branching transmission system and planetary gear train. In order to reveal the load distribution mechanism of power three- branching transmission system,the each gear torsion angle deformation coordination conditions,moment balance condition and elastic support condition under the power flow closed- loop characteristics are established,the load sharing coefficient is obtained. The influence of the installation error,floating and torsional rigidity on the load sharing characteristic is analyzed. The results show that the installation error is the main factor affecting the load characteristics,and the larger the error,the lower the load performance. The load sharing coefficient fluctuates between 1. 04 and 0. 96 when the sun wheel and the inner ring are floating. The load distribution is within 5%,which can improve the performance of the load.关键词：Installation error;Power three-branching;transmission Deformation;compatibility Floating;Load sharing
- 5
- |
- 104
- |
- 1
发布时间：2022-10-20 - 摘要：The structure and working principle of the plunger pump of the gear- linked cylinders hydraulic engine is put forward creatively for the issues that loose structure,more throttling lose,low efficiency and affected highly by working frequency that appearing in traditional plunger pump. And the structure and working principle of the gear- linked cylinders hydraulic engine are expounded. The plunger pump of the gear- linked cylinders hydraulic engine is a kind of liner reciprocating plunger pump that direct convert the indicated work into fluid pressure,it has advantages of compact structure and high volumetric efficiency. The kinematics research of the plunger pump of the gear- linked cylinders hydraulic engine provides reference for the later dynamics analysis,flow stress analysis,cam slot line optimization and prototype trial.关键词：Plunger pump;Cylindrical cam;Kinematics
- 5
- |
- 69
- |
- 2
发布时间：2022-10-20 - 摘要：The rolling bearing fault vibration signals are nonlinear and non- stationary and have strong noise background,in order to extract the fault feature effectively,a feature extraction technology which combines wavelet denoising and resonance- based sparse signal decomposition（ RSSD） is proposed. The resonance sparse decomposition is a new method for frequency division based on the tunable quality factor wavelet transform and morphological component analysis,it is different from conventional signal decomposition method based on frequency band partition,it is based on different oscillation forms of the signal components. Firstly,the signal is processed by wavelet threshold denoising,then,the signal is decomposed into two parts with different resonance characteristics by the resonance- based sparse signal decomposition method,The one is high- resonance component which has sustained oscillation characteristics,and the other is low- resonance component which has instantaneous impact characteristics. Finally,the impact fault feature is extracted from the low- resonance component by Hilbert envelope demodulation method. This method is applied to simulation signal and failure examples of impact on bearing test bench,the effectiveness of the proposed method is verified.关键词：Rolling bearing;Fault diagnosis;Quality factor;RSSD
- 4
- |
- 208
- |
- 1
发布时间：2022-10-20 - 摘要：Considering the influence of different nut installation modes,the finite element model of calculating the load distribution under the different working temperatures of the planetary roller screw mechanism（ PRSM） is established. The model is verified by comparing with the theoretical model under the working load.The effects of installation modes,load conditions and working temperature on the load distribution are analyzed systematically. Under different working temperatures,the numerical results show that the influence of installation modes on the screw side is bigger than the nut side. The temperature is one of the main reasons affecting the load distribution of PRSM and has a greater effect on the load distribution of screw side rather than the nut side. When the screw is in the state of tension or compression,the load distribution is becoming worse or better. In consideration of the reaction of the temperature with the load distribution,the screw and nut are all in compression is the best one in all installation modes.关键词：Planetary roller screw mechanism;Load distribution;Thermal-mechanical coupling;Installation mode;Finite element analysis
- 3
- |
- 142
- |
- 2
发布时间：2022-10-20 - 摘要：For the problem of kineto- static analysis for planetary gear train,the corresponding vector bond graph procedure is proposed. Based on the kinematic constraint condition of planar compound revolute joint,the procedure for modeling planar compound revolute joint by more concise vector bond graph is described. From the kinematic constraint relations of components of planetary gear train,the corresponding vector bond graph model of such system is built by assembling the vector bond graph model of tie rod,planetary gear,compound revolute joint and gear pair. By the effective augment method,the differential causality in the vector bond graph of such system is eliminated. By the corresponding algorithm,the computer aided modeling and dynamic analysis of planetary gear train system with double planetary gear is realized,the validity of the procedure proposed is illustrated.关键词：Vector bond graph;Planetary gear train;Kineto-static analysis;Compound revolute joint;Causality
- 4
- |
- 132
- |
- 3
发布时间：2022-10-20 - 摘要：The calculation of characteristic frequency of rolling bearing fault is the important theory basis for rolling bearing fault diagnosis and condition monitoring all the time. Through the experiments,discovering that the experimental results are fail to agree with the theoretical calculation value,the experimental data is not repeatable,the characteristic frequencies aren’t diploid related to each other,that is exist with the interharmonic frequency doubling error,and so on. Then,the root cause of errors of experiment results change characteristic frequency and interharmonic frequency doubling are analyzed and the methods of improving errors theoretically are discussed under the above basic study,a theoretical basis for rolling bearing fault diagnosis and improving method is provided.关键词：Fault characteristic frequency;Error mechanism;Interharmonic;Frequency refining
- 2
- |
- 167
- |
- 3
发布时间：2022-10-20 - 摘要：The remaining life prediction problem of gear is studied and a new set of gear life prediction program is put forward based on double exponential smoothing（ DES） and improved incremental support vector machine for regression（ SVR）. The new program utilizes principal component analysis（ PCA） to filtrate fusion index set,and then using DES to process fusion index set as the input of improved incremental SVR. Meanwhile,the improved incremental SVR prediction model is constructed based on incremental Latin hyper- cube sampling（ LHD） and Direct search algorithm. Compared with the standard SVR prediction model based on original characteristic values,the interference of signal randomness and mutation of the new model sre overcome,furthermore,the latest evolution trend information of the gear status is obtained,the optimization effect and prediction performance is obviously improved. The validation analysis of the new model is carried out by using the full life- cycle test data,the results show that the improved incremental SVR prediction model obtained a more reliable,more stable predictions,it has certain practical value in engineering.关键词：Double exponential smoothing;Fusion index set;Improved incremental SVR;Remaining useful life prediction
- 4
- |
- 131
- |
- 1
发布时间：2022-10-20 - 摘要：With the development of gear application technology,the higher requirements on gear precision are put forward,in order to achieve goals of high speed,high power,low noise and high transmission accuracy in gear transmission. In the gear hobbing process,if the tool geometry errors is ignored,the hob installation errors have become a major factor affecting the gear smooth precision. It starts from hob installation errors,the influence of hob installation errors on gear precision is analyzed. According to the principle of gear generating machining,the gear coordinate system and tool coordinate system are established,then by using the method of coordinate transformation,the gear tooth profile equation is deduced,which provides the design basis for 3D parametric gear precise modeling.关键词：Gear;Hob installation error;Tooth profile equation;Gear modeling
- 5
- |
- 101
- |
- 2
发布时间：2022-10-20 - 摘要：Taking the Lockup clutch in the hydraulic torque converter as the study object,the strategy of start- off slip friction control for the hydraulic torque converter lockup clutch is studied. At first,the dynamics model of lockup clutch and the clutch piston chamber pressure control model are analyzed. Secondly,a new start- off slip friction control strategy is proposed on this basis of the current lockup clutch slip control methods.Next,the clutch hydraulic circuit Simulation X model is established under the strategy of start- off slip friction clutch control. At last,the simulation analysis of the vehicle is carried out. The test results show that the start- off slip friction control strategy of lockup clutch can achieve well in start- off clutch locking processing,the friction time is greatly reduced and the efficiency of the torque converter is improved.关键词：Lockup clutch;Start-off slip friction control;Hydraulic control;Transmission efficiency
- 4
- |
- 190
- |
- 2
发布时间：2022-10-20 - 摘要：In terms of improving the processing accuracy and efficiency of globoidal indexing cams,the study on non- equivalent machining is carried out. The non- equivalent processing actual contour surface equation is established by rotating coordinate transformation to deduce and calculate the compensation amount and the compensation direction during the producing progress. Besides,the error is analyzed to through which one processing method would be put into practice to both improve processing efficiency meanwhile reduce processing costs and meet the processing accuracy requirement of globoidal indexing cam.关键词：Non-equivalent machining;Error analysis;Globoidal indexing cam
- 4
- |
- 87
- |
- 3
发布时间：2022-10-20 - 摘要：The wheeled robot has a complex nonlinear,strong coupling and time- varying dynamics characteristics,so taking the using of the traditional robot trajectory tracking control is easy to produce larger velocity mutation,and it bring about the chattering phenomenon of the robot in the process of control,and a kind of wheeled robot trajectory tracking control method based on parameter adaptive neural dynamic mechanics is put forward. By kinematical analysis,the posture error model of wheeled robot is established,the robot trajectory tracking controller is designed by using the neural dynamics. Through analyzing and comparing of the relationship between the different parameter selection and control,and a parameter adaptive method to further improve the performance of trajectory tracking controller is designed. Finally,the simulation experiment is carried on for the design of the control method. The experimental results show that the designed control method can ensure the robot have smaller velocity mutation,and convergence at a faster pace in case of error with high precision in trajectory tracking.关键词：Wheeled robot;Neural dynamics;Parameter adaptive;Trajectory tracking;Simulation
- 5
- |
- 82
- |
- 3
发布时间：2022-10-20 - 摘要：The mechanical system movement scheme design and selection is the key step in the design of mechanical system. The method for innovative design of mechanical system is proposed based on TRIZ（ Theory of inventive problem solving） and FAHP（ Fuzzy analytic hierarchy process）. According to the mechanical system performance index,the correlation matrix of the performance index and the engineering parameters of TRIZ are constructed. The solving procedure of conflict matrix of mechanical system is proposed. Aiming at the fuzziness and uncertainty of the mechanical system movement scheme evaluation,through constructing the fuzzy membership functions to select and evaluate,The validity of the method is verified by an example.关键词：Movement scheme;TRIZ theory;Fuzzy analytic hierarchy process;Innovative design
- 4
- |
- 173
- |
- 5
发布时间：2022-10-20 - 摘要：The parametric model of the cycloidal gear is established by using the equation of the trochoidal profiles on the platform of UG,and the 3D model of the RV reducer is established,then the virtual prototype model of RV reducer is obtained by importing the 3D model into ADAMS software. The rotational speed of the output shaft,the crank shaft and the cycloidal gear is obtained by simulation and the meshing frequency of the cycloidal gear and the pin tooth is investigated,the simulation results are in agreement with the theoretical results of the 9. 73 Hz,and the rationality and accuracy of the virtual prototype model is verified. The 8 groups virtual prototype models with consideration of the error are given,the simulation results show that the error of the pin radius,the modification of the cycloidal gear tooth profile and the error of the center circle of the pin have a great influence on the transmission accuracy. The research conclusions provide a theoretical basis for the design of RV reducer.关键词：Cycloidal gear;RV reducer;Virtual prototype;Transmission accuracy
- 4
- |
- 488
- |
- 5
发布时间：2022-10-20 - 摘要：Several issues of the calculation of the 18 Cr Ni Mo7- 6 carburized harden gear tooth root bending stress are discussed. The effects of the measuring direction of surface roughness Rzin the calculation of relative coefficient of tooth root surface condition YRrel Ton the accuracy of the results are analyzed. The effects of the deviation between the actual tensile strength and the reference tensile strength on the results of calculation are researched. Also,the static stress analysis is carried out on the tooth root bending stress by using the SolidWorks Simulation module,and the analytical results are close to the theoretical calculation results,which verifying the accuracy of the theoretical calculation results.关键词：Tooth root bending stress;Nominal tangential force;Relative coefficient of tooth root surface condition;Tensile strength;Finite element analysis
- 3
- |
- 186
- |
- 1
发布时间：2022-10-20 - 摘要：The existing energy management strategy which is based on driving pattern recognition failed to fully consider the battery state of charge（ SOC） falling fast in some driving cycle into consideration in the progress of driving. The 23 typical driving cycles are chosen from ADVISOR software and five categories are divided by using clustering analysis method,the key parameters of each category are optimized by using particle swarm algorithm,with the goal of reducing fuel consumption,relevant optimized results are saved in database,an energy management strategy optimization method of HEV based on driving pattern recognition is proposed.Finally,the simulation analysis for the energy management is carried out under a comprehensive test cycle,simulation results show that vehicle fuel consumption is cut down 12. 77%,and the deviation of the battery SOC have greatly decrease compare with other energy management strategy which based on driving pattern recognition.关键词：HEV;Driving pattern recognition;State of charge;Energy management strategy
- 3
- |
- 597
- |
- 1
发布时间：2022-10-20 - 摘要：The flexible transmission structure have more and more applications in minimally invasive surgical instrument. Due to the complexity of the structure,it is often difficult to calculate the mechanical property by the theoretical analysis of the structure. A double helix flexible transmission structure is proposed and the finite element model of the double helix structure is established in software ABAQUS and the influence of geometrical parameters on torsion stiffness of the double helix structure is analyzed,such as diameter,pitch,wall thickness and bottom radius. The results indicated that with the increase of nuclear diameter,pitch,thickness and bottom radius,the torsional stiffness increases,and with other parameters unchanged,the torsional stiffness and thickness are linear relationship,which has importance guiding significance for the design of the double helix structure.关键词：Double helix structure;Finite element analysis;Torsional stiffness
- 6
- |
- 113
- |
- 0
发布时间：2022-10-20 - 摘要：The synchronizer is an essential part of the manual transmission. The reference for synchronizer design is provided by studying optimization design of synchronizer. A mathematical model of lock ring synchronizer contact wear and optimization mathematical model with synchronizer life as the objective function are established based on principles of tribology and Majundar- Bhushan fractal theory. The optimization mathematical model is solved by APSO（ Adaptive particle swarm optimization） and the synchronizer life has greater increase than before optimization.关键词：Synchronizer;Fractal theory;Optimization design;Synchronizer life;APSO
- 3
- |
- 193
- |
- 1
发布时间：2022-10-20 - 摘要：The traditional methods of designing cam profile always leads to complicated calculation,low computational accuracy and efficiency. But by using Matlab programming language,the computational accuracy can be increased and the design period can be shortened in the process of solving and drawing cam profile.Firstly,the data points on the curve that are drawn in the Matlab can be derived. Secondly,a rough draft of cam profile is generated in Solid Works. Finally,the three- dimensional model of cam profile is created during the stretching process. This method is easy to operate and can greatly improve the design efficiency by quickly modifying the shape of cam profile according to the actual working conditions.关键词：Cam;Contour curve;Matlab;Solid Works
- 4
- |
- 358
- |
- 5
发布时间：2022-10-20 - 摘要：The gear backlash is in the process of gear and rack transmission,the gear backlash needed to be eliminated to ensure the bidirectional transmission precision of the transmission mechanism. In the designed mechanical mechanism,two racks meshing gears is driven through the axial relative displacement of the mechanism of sliding lead screw nut,and an axial relative displacement between the two racks（ gear rack staggered teeth） appeared,and the equivalent tooth thickness increased,and one mechanism is designed to eliminate gears backlash automatically. The mechanism is used in rotary table of NC machine driving by gear- rack successfully,it can obtain simple structure and high transmission precision.关键词：Gear;Rack;Backlash;Mechanism
- 4
- |
- 260
- |
- 5
发布时间：2022-10-20 - 摘要：To solve pitch curves of N- Lobed non- circular bevel gear being discontinuous,a novel pitch curve design method for non- circular bevel gear（ NCBG） is presented to simplify design of NCBG. The intersection curve equations between pitch cone surface of non- circular gear and spherical surface are derived,and the intersection curve is taken as pitch curve of NCBGs. The bevel gear with spherical involute is considered as generating cutter of NCBGs tooth profile,and mathematical models between pitch surface of bevel gear cutter and that of NCBGs are established. Based on this model,a machining simulation algorithm is developed. In addition,according to the characteristic of big end curve function of pitch cone surface of NCBGs,the causes of discontinuity and modifying methods of pitch curve of NCBGs are analyzed. The study results show that,the design defects such as undercutting and addendum overcutting of NCBGs can be identified quickly by applying the machining simulation algorithm,and it is exactly and effectively.关键词：Bevel gear;Design defect;Pitch curve;Undercutting
- 3
- |
- 29
- |
- 1
发布时间：2022-10-20 -
Design and Simulation of Shoulder Joint Rehabilitation Robot based on the Method of Nerve Repairment
摘要：The rehabilitation of the upper limbs of human body is determined by the recovery of shoulder joint movement function. Based on the analysis of the shoulder joint physical characteristics and movement characteristics of the shoulder joint,according to shoulder rehabilitation exercise training requirements,a novel shoulder joint rehabilitation robot is designed based on 3- DOF series- parallel mechanism. The shoulder joint has three rotation degrees of freedom and can complete three- dimensional composite sports. The series- parallel mechanism is adopted to ensure the neutral and stability of mechanism,and the mechanism movement space is increased. By using the Creo software,the three- dimensional modeling of the shoulder joint rehabilitation robot is carried out. According to the methods of nerve repairment,aiming at the rehabilitation of shoulder joint in soft paralysis,the shoulder joint rehabilitation robot is simulated. The results of the analysis show that the shoulder joint rehabilitation robot can meet the needs of patients with soft paralysis,and the design of the shoulder joint rehabilitation robot is reasonable. It laid a theoretical foundation for the design and research of shoulder rehabilitation robot.关键词：Shoulder joint;Rehabilitation robot;Serial-parallel;Movement simulation- 4
- |
- 191
- |
- 2
发布时间：2022-10-20 -
Research of the Rigid-flexible Coupling Dynamics Simulation Analysis of Auxiliary Standing Mechanism
摘要：Aiming at the problem of large deviation between the simulation results and the actual situation when regarding the pure rigid body as the smaller stiffness part with large force. Firstly,the working theory of auxiliary standing mechanism is sketched,then the rigid- flexible coupling dynamic simulation model is set up by utilizing the ADAMS and ANSYS. Based on the simulation model,the dynamic stress of upper and lower pipe in one movement cycle of the auxiliary standing mechanism is obtained,and the corresponding moment of the largest stress in the whole time course is further determined,then it is compared with the dynamic stress calculation results of the corresponding time in Workbench. The research results show that under the condition of the permitted error,the two results are basically consistent. The accuracy of theoretical calculation dynamic stress method based on the rigid- flexible coupling dynamics simulation model is verified,as the same time,compared with the finite element method,the analysis result of rigid- flexible coupling model can reflect the real dynamics behaviors of mechanism.关键词：Auxiliary standing mechanism;Flexible body;Rigid-flexible coupling;Dynamic stress- 1
- |
- 206
- |
- 0
发布时间：2022-10-20 - 摘要：Aiming at overcoming the deficiency of dynamic balance of crank- group mechanism,combining the mass moment substitution method and the momentum moment substitution method,the complete balance conditions of swing force and swing torque of crank- group driving mechanism are derived. The expressions of the additional mass moment and additional momentum moment of connecting rod truss that is equivalent in adjacent cranks and the dynamic balance conditions of two pair rod tree system can be obtained by solving a linear equation set. It is also proved that such institutions can achieve the balance of force and moment by adding the counterweight without inertia weight mechanism,the application of this dynamic balance method of crank- group mechanism has a theoretical significance for designing the physical prototype experiment and choosing the parameters of counterweight.关键词：Crank-group driving mechanism;Two pair rod tree system;Mass moment substitution method;Swing force balance;Momentum moment substitution method;Swing moment balance
- 2
- |
- 62
- |
- 3
发布时间：2022-10-20 - 摘要：In order to solve the problem of hydraulic excavator mechanical arm stress dynamic calculation,combining the virtual prototyping technology,finite element analysis techniques and dynamics theory,the modal reduction technique is used to establish flexible model of excavator boom and bucket rod. Furthermore,the rigid- flexible coupling system model of excavator is established and dynamics simulation is carried out. Finally,the stress of mechanical arm and hydraulic cylinder load are analyzed. The results show that the effect of structure static analysis is limited,the dynamics analysis which took motion and load characteristic into comprehensive consideration is more accurate in stress calculation. The maximum stress of boom and bucket rod is 107. 7 MPa and 40 MPa respectively. A theory basis for the structure optimization,accurate vibration control and life assessment for such structures is provided.关键词：Hydraulic excavator;Mechanical arm;Rigid-flexible coupling;Dynamics;Stress
- 5
- |
- 262
- |
- 3
发布时间：2022-10-20 - 摘要：Considering the inertial force in Reynolds equation,the thermal elastohydrodynamic lubrication analysis of the water- lubricated tenmat journal bearing is varied out. The effects of load,speed and surface roughness on the pressure and film thickness are discussed,and then compared with those without considering inertial force. The result show that as the fluid inertial force is considered,the pressure in inlet region,the central film thickness and the minimum film thickness are increased,but the pressure peak is decreased. The pressure peak is increased with the increase of load,but the film thickness is decreased. The pressure peak is decreased with the increase of speed,but the film thickness is increased. Considering the bearing surface roughness make pressure and film thickness oscillating,the pressure peak increased,the minimum film thickness decreased.关键词：Liquid inertial force;Water lubrication;Tenmat bearing;Thermal elastohydrodynamic
- 3
- |
- 140
- |
- 1
发布时间：2022-10-20 - 摘要：The rolling bearing performance degradation assessment method is proposed by the joint use of wavelet packet Tsallis entropy（ WPTE） and fuzzy C- means（ FCM）. Firstly,the WPTEs of normal data and final failure data are extracted followed by the evaluation model of performance degradation being built by using FCM. Then,the degree of tested data belonging to the final failure state is employed as an index to evaluate the level of bearing performance degradation in a quantitative way. Meanwhile,a threshold is set to alert incipient faults. Experimental analysis shows that the proposed index of bearing performance degradation is able to detect bearing fault in its early stage and has stronger robustness to the noise in comparison with the assessment method based on wavelet packet entropy and FCM. In addition,the proposed index has a value located in [0,1]and a reasonable interpretation to the evaluated bearing health condition.关键词：Rolling bearing;Performance degradation assessment;Fuzzy C-mean;Wavelet packet Tsallis entropy;Incipient faults
- 4
- |
- 211
- |
- 7
发布时间：2022-10-20 - 摘要：Firstly,the contact characteristic in the roller screw is introduced. Based on the Hertzian contact theory and the load distribution regulation of the roller screw,the model of friction moment is analyzed. The friction moment model shows that its influencing factors included in the half lengths of the major（ minor） of the contact ellipse and the sliding friction coefficient,on which the load of the roller screw has impact. The regularity between the load and the half lengths of the major（ minor） of the contact ellipse and the sliding friction coefficient values are discussed respectively. Finally,the relationship between the friction moment and the load of roller screw is obtained,which is compared to the results with the situation that regarding the sliding friction coefficient as constant. The result shows that,as the load increases 10% of rated load,the friction moment of roller screw increases correspondingly 16%. Furthermore,the consequence presents when the load larger than70% of rated load,the effects of the sliding friction coefficient changing with various load on the friction moment could not be neglected.关键词：Roller screw;Friction moment;Load;Sliding friction coefficient
- 3
- |
- 147
- |
- 3
发布时间：2022-10-20 - 摘要：The finite element simulation model of transient temperature field of drilling rig hydraulic brake discs is built up. The thermal- mechanical coupling simulation and calculation of model is carried out by using ABAQUS. The influence of parameters changing on distribution of temperature field and stress field is studied specially. The distribution of temperature field,stress field,as well as related conclusions are consistent when the parameters of convective heat transfer coefficient,braking time,thermal expansion coefficient,thermal conductivity,friction coefficient are changed only but braking conditions. For the brake discs,reduction in its holistic temperature and stress could be achieved by increasing the convective heat transfer coefficient and the thermal conductivity,reducing the thermal expansion coefficient and the friction coefficient. A theoretical guidance for optimization design of brake disc is provided by the conclusion of simulation analysis.关键词：Brake disc;Temperature field;Finite element method;Stress field
- 3
- |
- 146
- |
- 2
发布时间：2022-10-20 - 摘要：In the dynamic analysis of the assembly structure,there are three methods to simplify the connection between different components: node coupling,rigid / flexible connections and MPC algorithm. Through comparing the accuracy of the three methods in solid model connections and comes to the conclusion that the simplify accuracy of node coupling and MPC algorithm is higher than the rigid / flexible connection,while MPC algorithm is more convenient and practical. The MPC algorithm is applied to the modal analysis of a gearbox assembly,and a good result is got.关键词：Assembly;Node coupling;Rigid/flexible connection;MPC algorithm
- 2
- |
- 115
- |
- 3
发布时间：2022-10-20 - 摘要：As a new self- adaptive time- frequency analysis method,the local characteristic- scale decomposition（ LCD） is proposed lately and applied to mechanical fault diagnosis. The influence of noise to LCD is studied and a new fault diagnosis based on singular value decomposition（ SVD） de- noising and local characteristic- scale decomposition is proposed. Firstly,the phase space reconstruction of original vibration signal is carried out,and then,the noise is effectively eliminated by using singular value decomposition. The LCD of the de- noising signal is carried out and some intrinsic scale components（ ISC） are acquired,then the envelope spectrum analysis on the ISCs is carried out and the fault feature is extracted. Through the analysis of the simulation data and the bearing fault data,the effectiveness of this method is verified.关键词：Local characteristic-scale decomposition;Singular value decomposition;Phase space reconstruction;Bearing fault diagnosis
- 5
- |
- 188
- |
- 3
发布时间：2022-10-20 - 摘要：The contact characteristics of deep groove ball bearing（ DGBB） is one of the important factors that influence the DGBB property,for analyzing the influence of curvature radius on the contact characteristics of DGBB,taking the SKF618 /8 single row DGBB used in the planetary transmission mechanism as example.The stress,strain,velocity,contact force are simulated and analyzed based on the finite element software,and the influence of different curvature radius of inner ring,outer ring and the diameter of the roller on its contact characteristics are analyzed. The results show that the velocity,stress and strain of roller are variations in the form of peaks and troughs,and the stress,strain are mainly concentrated in the contact area between the roller and the inner or outer circle. The roller stress is increased with the curvature radius of inner ring,outer ring and rolling element diameter,moreover,the speed of the rolling element is greater with the longer of the distance to the center of rotation. Furthermore,the volatility and contact force of DGBB between the rolling element and inner or outer ring have the similar size,which basically the same with the radial load value,but the force between rolling element and maintains is small.关键词：Curvature radius;Deep groove ball bearing;Contact characteristic
- 5
- |
- 124
- |
- 2
发布时间：2022-10-20 - 摘要：An evaluation magnetic saturation rate is proposed due to magnetic saturation degree not clear in the magnetorheological device. The magnetic field finite element analysis of disc- type magnetorheological brake is carried out,and the simulation results are analyzed by magnetic saturation evaluation function. The results indicate that,the brake just happens to be magnetic saturation during the input current is 2 A. The structure of brake is optimized by magnetic saturation analysis and brake in before and after the optimization is analyzed by magnetic saturation evaluation function and magnetic saturation evaluation rate,the results indicate that,brake torque increased by 57%,the evaluation of magnetic saturation rate decreased by 0. 95%. Furthermore,the magnetic fields in the three types of magnetorheological brake are analyzed by using finite element in the case of equal of magneto motive force,the results indicate that,the side- wall- type brake and the excitation coil is the opposite winding of the resistance magnetic saturation capacity is the strongest,the outer- type brake of resistance magnetic saturation capacity is the weakest. The outer- type brake of working gap magnetic induction intensity distribution is more uniform,while the side- wall- type brake of working gap magnetic induction intensity distribution is uneven extremely. The working gap magnetic induction intensity distribution of the same- direction- winding is relatively even than the opposite- direction- winding in the side- wall- type brake.关键词：Magnetorheological brake;Finite element analysis;Magnetic saturation
- 3
- |
- 157
- |
- 1
发布时间：2022-10-20 - 摘要：The thin- spoke structure gear model is established by using 3D modeling software,and the finite element software is used for the pre- processing. The load history on single tooth is obtained according to the dynamics equation and load distribution,which is applied on the basis of meshing time. By this means,the force condition of gear under operation condition is simulated. The inherent characteristic of gear with thin-spoke is calculated,the graph of travelling waves is plotted. The steady responses and dynamic stress under operation condition and resonance speed is calculated through the method of modal superposition and the curve of dynamic stress is drawn. This method applies to analyze steady responses under different speed conditions of any kinds of gear. It provides reference for stress check and optimum structure.关键词：Aviation gear;Thin-spoke structure;Inherent characteristic;Steady response;Dynamic stress
- 2
- |
- 149
- |
- 5
发布时间：2022-10-20 - 摘要：For the application of the flexible hinge in the wind tunnel strain balance calibration system,the circular arc flexure hinges are used as the research object to calculate the maximum stress. The stress of a typical hinge is analyzed and the method which the circular arc flexure hinge is equal to straight round flexure hinge is presented. Based on the stress concentration theory,the stress concentration coefficient formulas of hinge are fitted when the hinge is applied axial force and bending moment respectively. The three dimensional models of different parameters are established,and the finite element simulation analysis is carried out by using ANSYS Wrokbench. The simulation data and theoretical calculation data are compared to verify the feasibility of the equivalent method and the fitting formulas.关键词：Flexure hinge;Stress concentration;Curve fitting;Finite element method
- 3
- |
- 230
- |
- 2
发布时间：2022-10-20 - 摘要：The working principle and characteristic of the braking energy recovery system are introduced.The working principle of automotive electromagnetic braking is introduced. The necessity and feasibility of electromagnetic braking applied in the braking energy recovery system are analyzed. By comparing the existing structure of electromagnetic braking applied in the braking energy recovery system,the key technology and development direction of system integration are put forward. The key research direction of integrated system are the optimization design of integrated system,braking mode switch control research and the expansion of the integrated system function.关键词：Electromagnetic brake;Braking energy recovery;System integration
- 3
- |
- 336
- |
- 3
发布时间：2022-10-20 - 摘要：By using the Hertz theory and the finite element analysis software named ANSYS Workbench,a static analysis is conducted for the overrunning clutch used in a new type of motor valve of the intelligent gas meter,and drum modification of the roller generatrix is conducted according to the analysis results. The improvement results show that the drum amount at 0. 010 mm,the maximum equivalent stress of roller decreased by 24% from 10. 3 MPa to 7. 8 MPa,so that the service life of overrunning clutch is improved. The improving design results could have a certain guiding significance on the working reliability and stability for the overrunning clutch.关键词：Overruning clutch;Static analysis;Drum roller;Improved design
- 3
- |
- 60
- |
- 0
发布时间：2022-10-20 - 摘要：Considering the efficiency and environmental issue in balloon inflating and sealing up work,an innovate design scheme cooperated by a variety of transmission structure which is ingenuity and meets the green design concept is put forward. Taking the core component cylindrical cam as an example and the parametric design analysis in its process is expounded and the mechanism is controlled to achieve precise movement by using function expression. On this basis,the optimization design based on the parameter- driven is further studied,by using the genetic algorithm in Matlab optimization toolbox and taking the resistance moment of inverse cam mechanism as objective,the model is modified and the parameter is reset by using the optimization result. The verification is carried out through the functional prototype testing and motion simulation analysis in Recur Dyn solver in UG software,and the optimized design in all the parameter driving is perfected.关键词：Parametric design;Green design;Genetic algorithm;Optimization design;Inverse cam mechanism;Slipknot machinery
- 3
- |
- 60
- |
- 0
发布时间：2022-10-20 - 摘要：Taking JMY175 industrial diesel locomotive for example,the structure composition of the axle gearbox is introduced. According to the reliability theory and the modern mechanical design optimization method,taking the volume,reliability,coincidence degree of the gear transmission as the target function,taking the gear parameter as design variables,reliability optimization design of the axle gearbox is carried out. The reliability of gear fatigue strength is combined within the constraint conditions,the optimal solution of the parameters is obtained,the results show that the volume is reduced by 35. 71%,and the reliability is improved by 2. 7074%,and the coincidence degree is increased by 12. 68%. The goals of reducing production cost,improving the stability of gear transmission and prolonging the service life of the gearbox are realized.关键词：Axle gearbox;Reliability;Optimization design
- 3
- |
- 111
- |
- 1
发布时间：2022-10-20 - 摘要：The CNC milling machine has the advantages of simple movement and high efficiency in manufacturing large modulus cylindrical gear. In order to improve the processing efficiency of rough milling,a method based on the double disk milling cutter is proposed for large modulus cylindrical gear. For one thing,the change law between the tooth profile allowance and the gear modulus with double,single disc milling type is obtained by establishing the mathematic model of tooth groove allowance of double disk milling. For another thing,in contrast with the traditional single disk milling,the time cost model,cutting- tool wear cost model and follow- up hobbing cutting wear cost model are established to investigate the relationship between the cutting cost and workpiece modulus for double disk milling. Finally,the feasibility of double disk milling is verified by an example of machining large modulus as well as the torque and force experiment. The experimental results show that the double disk milling method is a good solution for rough milling of large modulus gear.关键词：Numerical control machining;Double disk cutter;Large modulus cylindrical gear;Form milling
- 4
- |
- 55
- |
- 0
发布时间：2022-10-20 - 摘要：In order to improve the meshing performance of zero spiral bevel gears,a modified roll method of processing parameter design method based on local synthesis method for pinion is proposed. The tooth contact analysis model including assemble errors is established. The contact path and transmission error curve are obtained by solving the nonlinear equations system. Then,the major axis of instantaneous contact ellipse is calculated based on differential geometry. The numerical example results show that,a middle- convex parabolic transmission error with the amplitude under a smaller range is achieved by using the modified roll method. The shaft angle misalignment has greatest effect on the meshing performance,which need to ensure the installation accuracy.关键词：Local synthesis method;Tooth contact analysis;Modified roll method;Transmission error
- 3
- |
- 82
- |
- 1
发布时间：2022-10-20 - 摘要：The pile of tufted carpet can be loop pile,cutting pile and loop cut pile. The cut pile mechanism is an important part of the carpet tufting machine,it must make sure that the actions in cut pile tufting can be happened on time. The working principle and cooperation requirement of typical cut pile mechanismare analyzed,and a new type of cut pile mechanism is designed with reference to the structure characteristics of typical cut pile mechanism and the performance advantages of involute. And then,the kinematics models of two kinds of cut pile mechanism are set up by using MATLAB- Simulink. The results show that the mechanism design of the new cut pile mechanism is reasonable. it can satisfy the technological requirements of cutting pile and is much more simple and reliable than the typical cut pile mechanism.关键词：Involute;Carpet tufting machine;Cut pile mechanism;Cam groove;Kinematics analysis
- 3
- |
- 72
- |
- 0
发布时间：2022-10-20 - 摘要：<正>四月的北京,树绿草翠,气候宜人,第十二届全国机械无级变速器（CVT）及在汽车变速技术中应用学术信息年会于2016年4月26日-27日在北京举行。会议由中国机械工程学会机械传动分会机械无级变速器专业委员会与中国机械通用零部件工业协会齿轮分会联合主办,中国矿业大学（北京）协办。近30位来自国内高等院校、研究院所、生产企业从事机械无级变速器（CVT）研究、开发及生产的专家、学者、企
- 4
- |
- 89
- |
- 0
发布时间：2022-10-20
- Technical support is provided by Beijing Founder electronics co., LTD 豫ICP备05013835号-5
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0