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Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A study on the load characteristics of the modified gear planetary gear systems is conducted to address the issue of uneven loads between planetary gears due to manufacturing and installation errors, which result in deviations between the radial and circumferential installation positions of planetary gears and non-offset values. Based on the theory of rotor dynamics, the time-varying stiffness and the radial and circumferential offsets of the planetary gears are considered, and the five-degree-of-freedom dynamic model of the planetary gear transmission system with addendum modification is established. The response and frequency spectrum of the system are solved by the Runge-Kutta method. The load distribution characteristics of the planet gears under different radial offsets, circumferential offsets, and comprehensive offsets are analyzed. The influence of the radial and circumferential offset of the planetary gear on the load distribution of the planetary gear transmission system is discussed, and the variation law of the load vibration amplitude of the planetary gear transmission system with addendum modification under the time and frequency is obtained. The simulation results show that the load characteristics of the planetary gear train considering the error are quite different from those in theory. Its vibration amplitude of the planetary gear transmission system is greatly affected by the radial offset, and the large radial offset has the greatest impact on the load of the planetary gear. Small deflections of the planetary gear during installation can lead to large changes in the load characteristics. The planetary gear transmission system load test platform is built, the frequency-doubling vibration response signal of the planetary reducer housing is tested, and the relation between the planetary gear transmission system load force and vibration response is obtained. The amplitude variation trend in the experimental results is similar to that in the simulation analysis, and the correctness of the established model and solution method is verified.

Copyright of Journal of Henan University of Science & Technology, Natural Science is the property of Editorial Office of Journal of Henan University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Heilongjiang University of Science & Technology is the property of Journal of Heilongjiang University of Science & Technology Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to investigate the load-sharing performance of the 2K-H planetary gear transmission system， a translation-torsion coupling dynamics model is established with considering the nonlinear factors of time-varying meshing stiffness and the overall meshing error and so on， the dimensionless differential equations with 18 degrees of freedom of the system are deduced in this model. By solving the differential equations， the influences of the support stiffness of the center component and the clearance floating on the load-sharing performance of the planetary gear train are analyzed. It is shown that the floating amount of the component increases with the reduction of the support stiffness of the center component and the increase of the clearance of the shaft hole within a certain range， the load-sharing factor of the system decreases when the floating amount of the component increases.

Planes are the execution tools of coal plough,the work load directly affecting the planing capacity and production efficiency of the plow. In order to study the load characteristics,developing the coal plow load calculation program based on Matlab and VC,which can calculate the random load of planer at different positions according to the different simulating coal seam occurrence conditions; Planes at different positions were simulated and the strength verified based on ADAMS software. By analyzing the results indicate that : in the same cutting depth,the loads of planes at the different positions are random,in which load short broadsword’s means and standard deviations of the three load are minimum and the cutter force is relatively stable and uniform compared with other positions,followed by long broadsword,knife top and bottom knife; With increasing of planing depth,three forces of planes suffered have varying degrees increased,When the cutting depth exceeds a certain value,cutting resistance will be significantly increased; when the cutter spacing exceeds a certain transversal distance,cutting force increases sharply; In the working process,long and short waist by the maximum stresses are located in knife body thickness position transition connection and the knife body and the lamellar alloy head is embedded,main failure mode for the wear and fracture;the top and bottom knife knife connected with the knife base part chamfer can relax the stress concentration. Analysis results of load planer reliability and structure optimization design provides a theoretical basis for the study of dynamic.

The load（ working condition） coefficient is one of the important original inputs in the design of chain transmission system,it is directly related to design variables of the chain bearing capacity,especially for the timing silent chain system,the chain plate thickness or number are all related to it. Through a engine timing chain system design,ignoring the torsional vibration and engine cylinder to work,the load characteristics of the timing silent chain system are analyzed qualitatively. By using the cylinder head anti drag system test bench,through static and dynamic load torque test,the load coefficient and the method of determining under different speed conditions of the timing silent chain system are proposed,which is of great reference value to the design of the multi axis and high speed silent chain system.

Based on the coal rock cutting theory,simulated the load characteristic of the roller in the process of during coal rock; with the flexible-body dynamics as the theoretical basis to establish rigid-flexible coupling model of cutting unit,simulate the process of height adjustment by ADAMS and get the load response of link point; used Workbench to get the stress distribution of ranging arm when the link point force is maximum during the process of height adjustment; with linear cumulative damage rule as the theoretical basis,used Workbench to estimate the fatigue life of the ranging arm to verify the results of the reliability analysis and load response analysis.This paper provides a new method to research on dynamic characteristic and reliability of shearer cutting unit.

The conventional pneumatic tires have disadvantages in terms of puncture, blowout at high speed, pressure maintenance, and so on. Due to these structural inevitable weaknesses, non-pneumatic tires have been developed and are being investigated. A new non-pneumatic elastic wheel was proposed and studied to solve these problems. As an important bearing member of the non-pneumatic elastic wheel, the force of hinge group is very complex and it has a significant effect on the performance of the wheel. However, in the complex off-road driving, the hinge group has to withstand complex random load and impact load, and inevitably there will be damage failure. In order to explore the performance change of the wheel after the failure of the important bearing parts, it is necessary to study the influence of the hinge group with local damage on the performance of the non-inflated elastic wheel. In this paper, an experimental study on basic characteristics of non-pneumatic elastic wheel with local hinge group fracture damage was conducted in order to enhance the reliability. Based on tire characteristic test-bed, the tests on basic characteristics of static radical stiffness and contact behavior as well as the modal test were conducted. The wheel with local damage, one hinge group of which was disassembled, was used to simulate hinge group fracture condition in this paper. The results show that the effect of the hinge group fracture damage on the wheel load characteristics is the decrease of the radial stiffness, and it is also related to the damage position on the non-pneumatic elastic wheel. The radial stiffness of non-damaged non-pneumatic elastic wheel is 593.06 N/mm, and the corresponding values of the non-pneumatic elastic wheel with fractured hinge group on horizontal position and vertical position are 443.2 and 385.4 N/mm, respectively. Compared with non-damaged non-pneumatic elastic wheel, the numerical value of radial stiffness is reduced by 25% and 35% respectively on horizontal position and vertical position when the fractured hinge group is installed. That is to say the consistency of radial stiffness and deformation uniformity get worse for the wheel with local damage, so the poor performance of riding comfort of non-pneumatic elastic wheel appears. The influence of the hinge group fracture damage on the grounding pressure distribution is the change of grounded imprinting length and grounded area. Under the same vertical load, these 2 indicators of the non-pneumatic elastic wheel with fractured hinge group increase compared with non-damaged non-pneumatic elastic wheel. When the vertical load is 7 262 N, the imprinting length of the non-pneumatic elastic wheel with fractured hinge group on horizontal position is 138 mm, and the numerical value of non-damaged non-pneumatic elastic wheel is 120 mm. The ground imprinting length of the damaged wheel is increased by 15% compared with that of the non-damaged non-pneumatic elastic wheel. The grounded imprinting width does not change, and the value remains at 285 mm. As a result, the total grounded area of the damaged wheel also increases. The area of the non-damaged non-pneumatic elastic wheel is 34 200 mm2, and the area of damaged wheel increases to 39 330 mm2. The contact length and area of the wheel with local damage are greater than corresponding values of the non-damaged non-pneumatic elastic wheel under the same load. The influence of the hinge group fracture damage on the wheel modal test is the change of the natural frequency, the damping coefficient and the modal shape. In addition to a few orders, the natural frequency of non-damaged non-pneumatic elastic wheel is greater than that of non-pneumatic elastic wheel with local damage hinge group, and the damping coefficient of the most of non-damaged non-pneumatic elastic wheel is less than that of non-pneumatic elastic wheel with local damage hinge group. The value of the amplitude of modes gets smaller for the non-pneumatic elastic wheel with local damage hinge group. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper introduced the modeling method of exciter's excitation system，taking exciter's excitation system of 200 MW unit of a certain power plant in Heilongjiang as a research object，verified the feasibility of model establishment method through comparative analysis of the small disturbance test results and the simulation results，which provided the accurate calculation data for the stable operation and analysis of the power grid. [ABSTRACT FROM AUTHOR]

A dynamics model of herringbone planet train with double teeth coupling is established based on the vibration theory of the concentrated parameter. The mesh stiffness formula of the helical gear is introduced to calculate the time-varying mesh stiffness of the herringbone teeth in the way of stiffness parallel of two helical gears. The relationship curves between the mesh stiffness of the internal and external meshes and the dynamic load coefficients of the internal and external meshes are obtained by solving the dynamic equation, and the impact of the mesh stiffness of the internal and external meshes on the dynamics load characteristics of the train is analyzed. The research results show that the dynamic load coefficients of the internal and external meshes increase with the average components of the mesh stiffness of internal and external meshes without regard to the resonance, respectively. The impact of the alternate component of the mesh stiffness of the internal and external meshes on the dynamic load coefficients is much less. Because of smooth operation and small vibration of the herringbone tooth, it is feasible that the average component of the mesh stiffness represents the mesh stiffness for the calculation of dynamic load coefficient of herringbone planetary train, when the required accuracy is not too high. [ABSTRACT FROM AUTHOR]

According to the actual load suffered by a servo mechanism in a large launch vehicle, a comprehensive load simulation system was presented, which could simulate the inertia, elastic, friction and constant loads. The inertia load, elastic load and flexible assembling base of servo mechanism were simulated by the mechanical structures, and the friction load and constant load were simulated using a hydraulic system. A complete mathematical model was constructed by modeling the servo mechanism, its flexible structure and the loading hydraulic system. It is shown that this system can reproduce the load characteristics of the servo mechanism in actual situation, and the redundant force of the loading system is suppressed effectively. A load simulation system was developed for simulation of the loads and resonant characteristics, which provides the necessary fundamental facilities for ground test and further research of servo mechanisms. [ABSTRACT FROM AUTHOR]