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Effects of automatic variable preload device on performance of spindle 被引量:1
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作者 KIM Dong-Hyeon LEE Choon-Man 《Journal of Central South University》 SCIE EI CAS 2012年第1期150-154,共5页
To increase the machine accuracy by improving the stiffness of bearings,a preload was applied to bearings.A variable preload technology was necessary to perform machining processes in both low and high speed regions.A... To increase the machine accuracy by improving the stiffness of bearings,a preload was applied to bearings.A variable preload technology was necessary to perform machining processes in both low and high speed regions.An automatic variable preload device was fabricated using an eccentric mass.By installing the fabricated device on a spindle,the effect of the automatic variable preload device on the performance of the spindle was analyzed.In the results of the vibration measurement of the spindle,the vibration is increased by 20%-37% according to measurement points at the maximum rotation speed of 5 000 r/min.And,in the results of the noise measurement of the spindle,the spindle rotation speed is increased by about 1.9% and 1.5% at the front and side of the spindle,respectively.Based on the results of this analysis,an improved method that reduces such effects on the performance of the spindle is proposed. 展开更多
关键词 machine tool spindle automatic variable preload device VIBRATION noise
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THE HOMOGENEOUS DIRICHLET PROBLEM FOR QUASILINEAR ANISOTROPIC DEGENERATE PARABOLIC-HYPERBOLIC EQUATION WITH L^p INITIAL VALUE 被引量:1
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作者 王志刚 李亚纯 《Acta Mathematica Scientia》 SCIE CSCD 2012年第5期1727-1742,共16页
The aim of this paper is to prove the well-posedness(existence and uniqueness) of the L p entropy solution to the homogeneous Dirichlet problems for the anisotropic degenerate parabolic-hyperbolic equations with L p... The aim of this paper is to prove the well-posedness(existence and uniqueness) of the L p entropy solution to the homogeneous Dirichlet problems for the anisotropic degenerate parabolic-hyperbolic equations with L p initial value.We use the device of doubling variables and some technical analysis to prove the uniqueness result.Moreover we can prove that the L p entropy solution can be obtained as the limit of solutions of the corresponding regularized equations of nondegenerate parabolic type. 展开更多
关键词 degenerate parabolic-hyperbolic equation L p entropy solution device of doubling variables vanishing viscosity method
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Analysis and performance test on dynamic seed corn threshing and conveying process with variable diameter and spacing
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作者 Fei Dai Yiming Zhao +4 位作者 Yuanxiang Liu Ruijie Shi Shanglong Xin Qiufeng Fu Wuyun Zhao 《International Journal of Agricultural and Biological Engineering》 SCIE 2023年第2期259-266,共8页
In order to further reduce the damage rate in threshing seed corn,a seed corn threshing testbed with variable diameter and spacing that can realize dynamic adjustment of parameters,such as feed quantity,rotating speed... In order to further reduce the damage rate in threshing seed corn,a seed corn threshing testbed with variable diameter and spacing that can realize dynamic adjustment of parameters,such as feed quantity,rotating speed of the threshing device,threshing spacing of the threshing units,was designed in this research.The software of finite element analysis ANSYS Workbench was applied to do modal analysis on the threshing axis designed for variable diameter and spacing of seed corn.The first 8 orders of natural frequencies were distributed in 201.12-1640.20 Hz,with corresponding vibration amplitude in 5.86-27.04 mm,showing reasonable structural design of the threshing axis,which could realize effective seed corn threshing and conveying.Discrete element method was applied to do simulation analysis on the seed corn threshing and conveying process with variable diameter and spacing.Under the condition of different feed quantity,different rotating speed of the thresher,the moving speed of corn clusters and contact force among clusters were measured through simulation,and the working characteristics of the threshing testbed for low-damage and dynamic threshing and conveying of seed corn with variable diameter and spacing were revealed.Working performance test results of the testbed of seed corn with variable diameter and spacing showed that,when the rotating speed of the threshing axis was 190-290 r/min,feed quantity was 1.80-3.80 kg/s,the damage rate of seed corn was 0.32%-0.63%,threshing rate was 99.20%-99.82%,and content impurity rate was 4.23%-5.86%,the mass of threshed corn grains first increased and then decreased along the axial direction.The test verification process was in line with the simulation results;thus,the test results could satisfy the requirements in design and actual operation. 展开更多
关键词 seed corn threshing device with variable diameter and spacing threshing and conveying process performance test
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