最新刊期
期 10 ， 2019
- 摘要：Compared with ISO 6336:1996 edition，there are great changes in the latest edition of ISO/FDIS 6336-1 to 3：2019, in particular, the calculation of the helix angle factor for helical gear has a subversive change. In order to facilitate the reader to understand the changes of the new ISO 6336, the main changes in the content of different editions of ISO 6336 are introduced, the influences of the helix angle factors and single pair tooth contact factor on safety factor before and after modification are analyzed, and the influence of helix angle on the calculation results of contact strength and bending strength are discussed here with examples.关键词：Gear strength
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发布时间：2022-10-25 - 摘要：In order to study the gear bifurcation characteristic under the influence of tooth surface friction, based on the lumped parameter theory, considering the non-linear factors such as tooth surface friction, time-varying meshing stiffness, gear backlash and bearing clearance, a six-degree-of-freedom bending-torsion coupled vibration model of gear pairs is established. The Runge-Kutta numerical method is used to solve the model, and the influence of tooth surface friction on the bifurcation characteristics of the system is analyzed with various parameters. The results show that with the increase of rotational speed, the chaotic characteristics of the toothless surface friction are obvious, and with the increase of friction coefficient, the bifurcation outside the chaotic region will lead to the bifurcation inside the chaotic region. With the increase of tooth clearance, the amplitude of the system increases continuously without the tooth surface friction, and the chaotic state is inhibited with the increase of the tooth surface friction. With the increase of tooth surface friction, the blocking trend and suppression effect of the chaotic region are more significant with the increase of the damping coefficient.关键词：Tooth surface friction
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发布时间：2022-10-25 - 摘要：After the gear fault occurs， the vibration signal collected includes fault impact， deterministic meshing signal and noise signal， and these signals are also affected by the transmission path， which makes the gear fault feature extraction difficult. Cepstrum analysis is a common method for gear fault diagnosis. It can display the periodic components in the sideband as a single line， which is helpful for fault diagnosis. However， when the fault characteristic signal is weak， the fault characteristics in the cepstrum are not obvious. For this， feature-enhanced cepstrum analysis method is proposed. Three feature enhancement methods minimum entropy deconvolution， autoregressive linear prediction and wavelet de-noising are used to enhance the fault impact characteristics of gear vibration signals， and then the cepstrum is used to extract the fault features. The effectiveness of the proposed method is verified by experiment.关键词：Gear
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发布时间：2022-10-25 - 摘要：The quaternion is used to represent the finite rotation of rigid body, and the finite rotation equation of rigid body is obtained. Based on the spherical 3-RRR parallel robot, an angular displacement sensor bracket is added to detect the attitude angle of the moving platform, and the positioning deviation is transformed into a quaternion form. Thus, the robot is applied to the actuator of the spatial positioning problem. Aiming at the large-scale asymptotically stable dynamic quality of the system, the conditions that the angular velocity of the moving platform should satisfy are obtained, and the quaternion differential equation of motion of the moving platform in the positioning process is established. The solution trajectory of the deviation quaternion and the change course of the attitude of the moving platform during the positioning process of the robot are given by an example. The control law applied to the active component is obtained. The simulation results show that the control effect is better.关键词：Spherical parallel robot
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发布时间：2022-10-25 - 摘要：The parallel module of Exechon machine tool is developed based on the 3 degree-of-freedom (DOF) 2UPR-SPR mechanism, which is a parallel spindle head with two rotational (orientational) DOFs and one translational DOF. The output axis of moving platform designed as the deviation type can enhance the orientational capability of mechanism. The tilt-and-torsion angle with zero-torsion is used to descript the orientation of moving platform, and the mathematical model is constructed to solve the inverse displacement of the mechanism. On the basis, this study employs local transmission indices (LTI) as the criterion to evaluate the motion/force transmissibility, and analyses the good transmission orientational workspace (GTOW) and good transmission orientational capability (GTOC) of manipulator. This work gives an example of orientational capability analysis and plots the distribution atlases of LTI and GTOW, and the surface of good transmission workspace. Furthermore, the comparison and analysis results indicate that the manipulator with deviation output axis has better performance than one with orthogonal output axis in terms of GTOC, and the GTOC corresponded with the optimal deviation angle can achieve 46°.关键词：Parallel manipulator
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发布时间：2022-10-25 - 摘要：On the basis of kinematics analysis, the rigid-flexible coupling dynamics simulation model of the tripod sliding universal coupling is established by using RecerDyn software. The variation of contact stress of the sliding rod of the transmission element with the parameters such as the angle between the input shaft and the output shaft, rotation frequency and load is analyzed in depth. On this basis, the fatigue life of tripod slip universal coupling is predicted based on the stress time history life calculation criterion. The research results lay a foundation for further analysis of the dynamics characteristics and lubrication characteristics of the tripod sliding universal coupling, and provide a basis for its structural design and application.关键词：Tripod sliding universal coupling
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发布时间：2022-10-25 - 摘要：In order to study the nonlinear deformation behavior of bolt-flange-joined laminated coupling under three different load forms of tension, bending and torsion load, a local finite element model of the coupling is established. The effects of bolt preload and interfacial friction coefficient on the deformation of the laminated coupling and the stiffness of the bolt flange connection are analyzed. The relationship between the radial or circumferential slip and the nonlinear deformation of the coupling is discussed. The results show that reducing the preload and friction coefficient can effectively reduce the lateral and torsional stiffness of the laminated coupling, but the influence on the bending stiffness is limited. The friction coefficient and the bolt preload have a similar influence mechanism on the torsional stiffness. Research results can provide a useful reference for the design of laminated coupling.关键词：Laminated coupling
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发布时间：2022-10-25 - 摘要：For the need to increase effect of volume utilization rate and volume efficiency for roots pump，a new profile geometry of circular arc rotors with seal convex head and eccentric circular arc is proposed. Firstly，based on the profile geometry of common circular arc rotors，the eccentric arc rotor profile is formed by eccentric design to improve the shape coefficient and volume utilization ratio. Secondly，the shape coefficient and volume utilization rate are further improved by the design of convex top arc for sealing. Thirdly，The shape coefficient and volume utilization ratio of the two blades of the three circular rotors are calculated as examples. All results indicated that the percentage increase of shape coefficient and volume utilization rate with eccentric circular are 1.42% and 2.24% higher than common arc rotors. And the half angle of convex head is from 1° to 8°，the percentage increase of shape coefficient and volume utilization rate of two blades arc rotors with convex head is from 1.95% to 7.26% and from 3.58% to 11.84% higher than common arc rotors，increase effect was obvious. And the convex head structure is simple and easy to process. It is concluded that a new enhancement design is provided for other profile geometry in roots pump.关键词：Roots pump
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发布时间：2022-10-25 - 摘要：Based on Adams software, a multi-rigid-body dynamics model of the spindle transmission system of the peeling machine is established. The key components of the spindle transmission system of the peeler are flexibly processed by ANSYS, and the rigid-flexible coupling model of the spindle transmission system is constructed. The gear engagement process of the spindle transmission system is simulated by simulating the rotating speed of the gears at all levels of the spindle transmission system and setting the contact force parameters of the gears. The transmission ratio of the gears is verified. It is determined that the acceleration fluctuation mainly depends on the excitation frequency. At the same time, the tangential direction of the driving gear-transmission gear and the transmission gear-spindle gear is determined. The simulation values of force and radial force are 3 649.21 N, 1 580.15 N, 3 598.64 N and 1 415.13 N, respectively, which are in good agreement with the theoretical values, and the reliability of the simulation is verified by gear meshing frequency. Finally, 10 nodes with the maximum equivalent stress of three flexible parts in the simulation process are extracted, and the results are lower than the allowable stress of gear material, which can provide theoretical reference for the design and manufacture of the spindle drive system of high-performance peeler in practical application.关键词：Peeling machine
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发布时间：2022-10-25 - 摘要：Based on the exact conjugate method of harmonic gear drive， the tooth profile design method of the tri-arc harmonic gear drive is proposed and the influence of flex spline profile parameters on the conjugate interval are studied. The research results show that the tri-arc harmonic gear drive has a wider conjugate zone and a smaller interval between conjugate zones than the double circular arc harmonic drive. Reducing the radius of the convex tooth profile is helpful to increase the conjugate zone, but not conducive to reduce the interval between conjugate zones. Reducing the radius of the intermediate arc, the angles and are help to increase the conjugate zone, and also to reduce the interval between conjugate zones. The radius of the concave profile has little effect on the actual conjugate zone. Appropriate profile parameters of flex spline can bring a wider conjugate zone and shrink the interval between conjugate zones, which may facilitate the conjugate contact between the teeth as well as the improvement of transmission accuracy and torsional stiffness of harmonic drive.关键词：Harmonic drive
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发布时间：2022-10-25 - 摘要：To better improve the performance of master manipulator, reduce the fatigue caused by the gravity of the mechanism during operation, and improve the positioning accuracy, a master manipulator with seven degrees of freedom is designed. The boom mechanism is a parallelogram mechanism that provides front & rear and left & right degrees of freedom (DOFs). The arm mechanism provides up & down degree of freedom (DOF). The wrist mechanism provides pitch and yaw DOFs. The end operator mechanism provides roll, and opening & closing DOFs. On the basis of the structure design of the master manipulator, the kinematics model and error model of the master manipulator are established by using screw theory to improve the positioning accuracy. The kinematics parameters are identified by using the least squares method. The kinematics calibration experiment is carried out. The results show that the maximum position error of the master manipulator is improved by 67.43% after kinematics parameters calibration.关键词：Master manipulator
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发布时间：2022-10-25 - 摘要：A micro-displacement transmission mechanism with giant magnetostrictive actuator (GMA) as the driving unit is designed, which uses lever-type flexure hinge for displacement commutation and amplification. Based on the theory of elasticity, the amplification ratio and natural frequency formulas of the flexible commutation amplification mechanism are derived by considering the deviation of the rotation center of the flexure hinge. The geometric parameters of the flexure hinge, such as radius R and minimum thickness t, are optimized and analyzed by using the software of Matlab, by which the optimized geometric parameters of the flexible hinge are obtained and the optimized results are analyzed by finite element analysis. Finally, the simulation results are compared with the theoretical analysis results. The results show that， the correctness of the theoretical model is verified by theoretical analysis and finite element analysis， and the design objective in high amplification ratio, displacement commutation and linear output is achieved.关键词：Flexible commutation amplification mechanism
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发布时间：2022-10-25 - 摘要：Aiming at the problem that the output angle of the elliptical gear planetary gear train reversing mechanism with small beam pumping unit is small and can not meet the long stroke demand, the influencing factors of the output swing angle of the mechanism are analyzed, and the results are expressed in the transmission ratio curve of a pair of non-circular gear pairs with the graphical area. According to the analysis results, the non-circular gear pair transmission ratio curve that meets the application requirements is constructed, the section curve equation of the non-circular gear is solved, the three-dimensional model of the mechanism is established and the motion simulation is performed, and the output swing angle and the output angular velocity amplitude curve are obtained. Analysis results show that， compared with the original elliptical gear planetary gear train reversing mechanism, the swing angle of the output is increased, so that the stroke of the pumping unit can be increased.关键词：Pumping unit
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发布时间：2022-10-25 - 摘要：In order to improve the parametric design and manufacture of general cylindrical worm, a parametric design and manufacture software of general cylindrical worm is developed based on the mathematical model of general cylindrical worm, the meshing principle of gear, the structure of worm grinder and the processing technology of worm. Taking the general straight cylindrical worm (ZN-type worm) as an example, the geometric mathematical model of the general straight cylindrical worm is established, according to the spatial position and posture relationship between the worm and the grinding wheel and the gear meshing principle, the mathematical model of the profile of the formed grinding wheel for grinding worm is deduced. Based on Visual C++ 6.0, the software of worm design and manufacture is developed, which includes product management module, worm parameter input module, worm linear transition module, worm linear adjustment module, grinding wheel profile calculation module and processing code generation module. In order to verify the correctness of the developed software, SK6505 NC worm grinder is used to grind the general straight cylindrical worm. The results of measurement after grinding verify the correctness of the software.关键词：Cylindrical worm
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发布时间：2022-10-25 - 摘要：Cycloidal pinwheel planetary transmission is a kind of transmission method commonly used in industry. It is difficult to accurately process the position and the radius of pins as theoretical values when cycloidal wheels and pin wheels are machined and assembled. They are random variables that fluctuate in the range of machining errors. This will affect the meshing of the cycloidal pinwheel. The meshing force affects the accuracy and stability of cycloidal pinwheel planetary transmission，and then affects transmission error. A method for calculating the meshing force of cycloidal pinwheel based on Hertz formula is presented. It is proposed that there exists a combined random error of position and radius of pins during the meshing of cycloidal gear and pins. The formula for calculating the relative rotation angle considering this random error is deduced. The meshing force with considering the random error is further studied with an example. And the influence of meshing force on transmission error is analyzed. The computational model can be used for reference in the transmission accuracy design of robot high precision reducer.关键词：Cycloidal pinwheel
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发布时间：2022-10-25 - 摘要：The wear of ring sprocket is the main factor affecting the service life of ring chain. In order to analyze the key parameters affecting the wear of ring sprocket, by using the SolidWorks， the model of driving sprocket and ring chain of scraper conveyor is built, and the multi-factor and multi-level orthogonal experiments are designed. The stress state when the sprocket with different parameters contaccts with the ring china is analyzed by ANSYS Workbench module. According to the experimental results, the influence of sprocket parameters on the contact stress of driving sprocket and ring link is analyzed, and the optimum combination of parameters in several tests is determined. The analysis and verification results prove the validity of the research conclusions.关键词：Scraper conveyor
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发布时间：2022-10-25 - 摘要：Based on the principle of tooth surface contact analysis considering system meshing misalignment quantity, taking the design of spiral bevel gears of an aeronautical reducer as an example, the calculation model of meshing misalignment quantity is analyzed and established. The meshing misalignment quantity of the system is calculated under the influence factors of manufacturing error, assembly error and loading deformation, and the design of tooth surface considering the meshing misalignment quantity is carried out. The tooth surface contact mark (TCA), loading mark (LTCA), transmission error, relative sliding speed of tooth surface, temperature rise of tooth surface and assembly mark and running-in mark in engineering application are obtained, and the processing parameters of gear pair are generated. The accuracy of the above design method is verified by the fatigue test of the actual gears, which provides a reference for the design, production and application of spiral bevel gears.关键词：Spiral bevel gear
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发布时间：2022-10-25 - 摘要：Series Elastic Actuator （SEA） can effectively improve the flexibility of the joint. However, SEA has the disadvantage of strong nonlinearity of force and deformation. In order to improve the linearity of SEA, a curved beam model with double-ring connection is established, and the stress formulas of different points of the beam model are got by using the normal stress formula of the origin of the axis section, so as to design and verify the series elastic actuator which conforms to the flexible joint. Secondly, the model of the series elastic actuator is simulated and analyzed, and seven points are selected to compare the model with the actual stress. Finally, ANSYS is used to simulate and analyze the strength and deformation of each joint，which effectively guarantees the linear characteristics of SEA and improves the mechanical properties of flexible joint.关键词：Manipulator
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发布时间：2022-10-25 - 摘要：There are elastic deformation and rigid-flexible coupling effects in the motion of parallel mechanism, which have great influence on the motion and stability of the mechanism. Aiming at the above problems, taking the 3-DOF rigid-flexible coupled parallel robot as research object， based on linear MSTMM， the multi-body system model and topological structure model of rigid-flexible coupled robot are established, and the spatial transformation equation and dynamics equation of the whole system are derived. Then the simulation model of robot SimMechanics is established by Matlab software, and the trajectory tracking of the robot is simulated based on PID control strategy. The simulation results show that the actual trajectory of the robot is in good agreement with the expected trajectory, and the system motion is stable. Thus the correctness and effectiveness of the modeling method are verified， a theoretical basis for further research on the parallel mechanism is provided.关键词：Parallel robot
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发布时间：2022-10-25 - 摘要：In order to analyze the relationship between the nonlinear characteristics and the performance continuity reliability of rolling bearing vibration, based on chaos theory, a new concept is proposed for continuity relation dimension to characterize the nonlinear characteristics of rolling bearing vibration. Simultaneously， based on the maximum entropy principle and Poisson counting principle, the vibration performance continuity reliability model of the rolling bearing is established, and then the matching sequence of nonlinear characteristics and the vibration performance continuity reliability of the rolling bearing vibration are established. The experimental results show that the evolution of nonlinear characteristics and the vibration performance continuity reliability of rolling bearing vibration are closely related to each other, and the trend of change is consistent and reliability changes can be inferred based on the changing trend of the relation dimension. The proposed method provides a novel idea for the reliability prediction of rolling bearings.关键词：Chaos theory
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发布时间：2022-10-25 - 摘要：Based on bond graph, a modern modeling method for multi-energy domain coupling system, a mathematical model of multi-nonlinear coupling system of PMSM-2R mechanism is established and solved by Runge-Kutta method. In the coupled system, the effects of the coupling between multi-nonlinear systems on the dynamic characteristics of the system are analyzed by the two-parameter chaotic edge method, bifurcation diagram and the maximum Lyapunov exponent. When each subsystem is in the state of chaotic motion, he active control method is used to control the chaotic motion by adjusting the coupling strength. It is found that when the coupled subsystems are in chaotic motion state, the dynamic characteristics of the system change with the change of coupling strength, and the chaotic attractor disappears with the increase of coupling strength, gradually changing from chaotic motion state to periodic motion state.关键词：PMSM-2R mechanism
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发布时间：2022-10-25 - 摘要：A 16-DOF heavy-load RV reducer dynamics model is established by the lumped parameter method. Taking the RV-550E heavy-load reducer as the research object, the natural frequency of the reducer is obtained by solving the dynamics equation, and the influence of the pin-tooth shell stiffness on the natural frequency of the system is analyzed, which provides the basis for the design of the pin-toothed shell. In order to reveal the law of the influence of system parameters on the inherent characteristics of the whole machine, the sensitivity of the natural frequency of the whole machine to the moment of inertia and stiffness of the system is further analyzed. The analysis results show that the low-order natural frequency is more sensitive to the crankshaft arm bearing stiffness, the planet carrier support bearing stiffness and the crankshaft inertia. The research results provide a theoretical basis for the structural optimization design of this type of heavy-load reducer.关键词：Heavy-Load RV reducer
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发布时间：2022-10-25 - 摘要：The dynamics model of friction clutch of a mine locomotive is established, and the angular speed and heat flux of the master-slave friction disc in engagement process are solved by Euler method. The radial heat conduction equation of engagement process of friction disc in wet clutch is established, and the differential quadrature method is used to discretize the heat conduction equation and boundary conditions. The Runge-Kutta method is used to calculate the temperature rise of friction disc changing with time and radius under nominal and full-load conditions of mining locomotive. The results show that the radial varying temperature of the friction disc increases with the increase of time and radius during the engagement process. The greater the load, the longer engagement time and higher corresponding temperature. This conclusion provides a theoretical basis for the design and performance analysis of friction clutch.关键词：Wet clutch
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发布时间：2022-10-25 - 摘要：Aiming at the problem that hedge manipulators can’t work in complex and unstructured environments, a redundant line-driven hedge trimming manipulator with stronger environmental adaptability, higher degree of freedom and larger workspace is proposed. The kinematics model of single joint is established by coordinate analysis method, and the mapping relationship between rope length and joint rotation angle is solved. The forward kinematics mathematical model of 10-DOF manipulator is analyzed based on D-H parameter method. The inverse kinematics of redundant manipulator is studied by genetic algorithm, and the inverse kinematics of redundant manipulator is solved. The simulation results show that the genetic algorithm has high accuracy and fast solution. The coupling between the joints and ropes of the manipulator is analyzed and the decoupling formula is deduced. The correctness of forward and inverse kinematics model and decoupling model of the manipulator are verified by simulation, which lays a foundation for the control and trajectory planning of the rope-driven redundant manipulator.关键词：Line drive
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发布时间：2022-10-25 - 摘要：The nonlinear dynamics model for a spur gear pair system is established where the mild wear and crack faults are considered. The nonlinear dynamics equations with faults are solved by employing 4~5 order variable step size Runge-Kutta method. The bifurcation diagrams， phase portraits and Poincaré maps of the single-stage gear system under the condition of no fault, mild wear fault and crack fault are obtained to research the nonlinear dynamics characteristic of system. The dynamics behaviors of gear system in fault-free and fault are studied. The conclusions provide theoretical reference for fault diagnosis, dynamic design and safe operation of gear system.关键词：Spur gear pair
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发布时间：2022-10-25 - 摘要：A dual planetary row and dual motor coupling mechanism is proposed to solve the problems of low power per unit mass， low power at low speed and low utilization rate of high speed and low torque in single motor electric vehicles. Firstly， the dynamics analysis of the new coupling mechanism is carried out. The parameters of a dual-motor electric vehicle are matched to analyze the coupling characteristics of the two motors. Secondly， the control strategy is designed based on the required torque， speed， acceleration and motor efficiency. Finally， the corresponding driving module and control strategy module are built in Matlab/Simulink according to the mathematical model of each part of the vehicle， and the mathematical simulation is carried out. The results show that， in terms of power performance， the new dual planetary platoon power coupling structure and control strategy can meet the driving requirements of low-speed， high-speed and high-power vehicles， and also play a positive role in improving the economic performance of electric vehicles.关键词：Double planetary row
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发布时间：2022-10-25 - 摘要：To measure pitch deviation of mega spur gears, a new method for measuring the pitch of mega spur gears based on laser tracker is proposed. The measuring ability of laser tracker in large space is used to measure gear groove, and two adjacent pitch error curves of measured mega spur gear are obtained respectively. Because of the diameter of measured gear exceeds 6 meters, the single pitch error can be approximately calculated according to the formula of point-to-line distance. Firstly, the pitch measurement model of the gear workpiece coordinate system based on laser tracker is analyzed, and according to the characteristics of the mega spur gear, the pitch error measurement model of the mega spur gear without coordinate system based on laser tracker is proposed. The measurement model avoids the establishment of workpiece coordinate system of mega gear and directly measures tooth space with two-sided contact condition. By evaluating the errors of two measuring straight lines of the tooth space, the max single pitch error and the average single pitch deviation can be obtained. By transferring station measurement of laser tracker, total cumulative pitch deviation can be obtained. Finally, the uncertainties of system measurement of different measurement model are simulated and analyzed by the Monte Carlo method. The experimental results show that the method for measuring the pitch of mega spur gears based on laser tracker meets the single pitch deviation measurement requirements of 8-grade mega spur gears with diameter of more than 6 meters, and meets the total cumulative pitch deviation measurement requirements of 10-grade mega gears with diameter of more than 6 meters.关键词：Mega Spur gear measurement
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发布时间：2022-10-25 - 摘要：Fast kurtosis specturm has fast detection ability for transient impulse signal and is widely used in fault feature extraction of rotating machinery. A process of extracting mechanical fault feature based on fast computation of kurtogram is proposed and which is applied to the fault feature extraction of composite planetary gears of a tank gearbox. Firstly, the signals of gear normal and spalling fault under specific conditions are analyzed, and compared with the traditional envelope analysis results, it shows that the fault feature extraction method based on fast kurtosis specturm can significantly enhance the amplitude of fault feature frequency. In order to further verify the adaptability of test points and the effectiveness of feature extraction method, 32 test conditions are designed considering gear, rotating speed and load. The test data of each condition are analyzed, and the influence of operating parameters such as rotating speed and load on fault feature extraction is studied. The results show that the fault feature frequencies can be effectively extracted from the data collected by the selected measuring points under various working conditions, and the increase of rotational speed and load is helpful to the fault feature extraction.关键词：Fast kurtosis specturm
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发布时间：2022-10-25 - 摘要：Aiming at the characteristics of non-linear, non-stationary, multi-noise and multi-fault signals of the compound fault signal in gearboxes, a compound fault diagnosis method for gearboxes based on variational mode decomposition and correlated kurtosis is proposed. According to the characteristic that the signal can be effectively decomposed into several compact intrinsic mode functions by variational mode decomposition, the compound fault signal are decomposed into several intrinsic mode functions which contains different faults. Then，according to the characteristics that correlated kurtosis can identify the impact signals with different periods, the intrinsic mode functions containing different faults are extracted by using the maximum correlated kurtosis principle. Finally, the envelop analysis of these intrinsic mode function is carried out to achieve the purpose of compound fault diagnosis. The validity of the proposed method is proved by the analysis of the experimental signal. In addition, the influence of the number of intrinsic mode functions on the result of the proposed method is analyzed, which provides an empirical conclusion for the follow-up study.关键词：Gearbox
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发布时间：2022-10-25 -
Fault Recognition Method of Transmission Gear based on Morphological Wavelet and Permutation Entropy
摘要：Based on the in-depth study on morphological wavelet with permutation entropy，a new method for gear of transmission fault recognition is proposed. Firstly，the definition of morphological wavelet is introduced，and the morphological Haar wavelet is used to pre-process the measured gear of transmission vibration signal. Then，the permutation entropy is used as the eigenvalue of gear fault to extract the vibration signal, which included four working conditions: normal，slight-worn, medium-worn and broken teeth. Finally，according to different faults corresponding to different permutation entropy distributions，the various fault states are classified，and the permutation entropy distributions of non-denoised signals are compared. The example of gear fault recognition proved that the combination of morphological wavelet and permutation entropy could effectively improve the ability of gear of transmission fault classification.关键词：Transmission- 4
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发布时间：2022-10-25 - 摘要：The method of machining negative pressure angle spiral clutches with disc milling cutter and gear milling machine is studied. The mathematical model is established according to the characteristics of spiral clutches firstly, and the coordinate transformation relationship from the cutting tool system to workpiece system, the tooth surface points and mismatch quantity are calculated after selecting the appropriate initial value of the surface coordinates. Based on the above analysis, the 3D model of the clutch and mismatch analysis are completed after an example is introduced. To verify the tooth surface calculation theory, the machining simulation is carried out. The correctness of calculation and the feasibility of method are verified.关键词：Negative pressure angle
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发布时间：2022-10-25 - 摘要：The necessity of integrated energy-saving reform of boiler feed water pump is explained， the improved scheme of planetary hydraulic speed regulating device is put forward， and its working principle and energy saving characteristic is expounded. Taking a power plant in Xinjiang as an example， the renovation project of feed water pump unit replacing hydraulic coupling with the original size of planetary hydraulic speed regulating device from mechanical system， lubricating oil system and electrical system is carried out. A detailed comparative analysis of the feasibility， economy and effect of the comprehensive energy saving reform of the feed water pump is carried out. It is concluded that the advantages of planetary hydraulic speed regulating device can reduce the power consumption rate of power plant by 0.41%， and at the same time have the characteristics of safety， stability， high efficiency and energy saving.关键词：Feed water pump
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发布时间：2022-10-25
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