Papers by Keyword: Ceramic Ball

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Authors: Jing Ling Zhou, Guo Qing Wu, Xiao Yang Chen, Wei Nan Zhu
Abstract: By using a new type pure rolling fatigue test rig with three contact points for silicon nitride bearing ball specimen, the contact deflection angle of specimen with three contact points is calculated. The effects of the center height and test ball radius on the specimen contact deflection angle are analyzed. The analysis indicates that the span of contact deflection angle is 0-0.181° while the center height is 1.2mm and the design radius is 6.35mm and the specimen radiuses change from 4mm to 8mm. The more contact deflection angle is, the more variation rang of test ball radius is. The contact deflection angle can be less than 0.2° while the center height is optimized. The contact deflection angle has a direct influence on the stress error of the specimen. It is less than 1% while the contact deflection angle is less than 0.2°. The research provides a theoretical basis for optimization of test rig structure size and increase of specimen’s extension and improvement of test precision.
Authors: Jing Ling Zhou, Wei Ming Zuo, Xiao Yang Chen, Guo Qing Wu
Abstract: A newly developed pure rolling fatigue test rig with three contact points for bearing balls was used to perform rolling contact fatigue (RCF) tests and the fatigue properties of two kinds of zirconia ceramic balls produced with different materials composition and identical technologies were compared. Ball surfaces were examined after failure with optical microscopy and scanning electron microscopy. It was identified by tests that the failure mode of zirconia ceramic balls was surface spall. Life tests data, summarized in accordance with the Weibull theory, showed that the life of two kinds of zirconia balls was close, and no remarkable difference in the divergence between the tested two kinds of balls was found
Authors: Jing Ling Zhou, Xiao Yang Chen, Guo Qing Wu, Jian Chun Chen
Abstract: Silicon nitride ceramic ball surface is examined after failure with scanning electron microscopy. The profile of the fatigue spalling takes the shape of an ellipse. The failure cause, fatigue phenomenon and mechanics are analyzed. The research shows that subsurface cracks play a dominant role in the formation of spalling failure. These cracks originated from volume defects of the material, and propagate, to form fatigue spalls under the action of principal tensile stresses. The contours of equal tensile stress of Oxy plane underneath surface are elliptical. Subsurface cracks are shape of ellipses and spall is also of the elliptic shape. The principal tensile stress increases with increasing contact load, causing spall formation and reduction of rolling contact life.
Authors: Jian Jun Zhou, J.X. Hu, Min Huang
Abstract: Geometric design procedures for the cycloidal drive with ceramic ball meshing elements were introduced. Using the theory of conjugate surfaces, the equations of meshing of the cycloid drive and the cycloid raceway profiles were derived. Design examples were presented to demonstrate the design procedure and feasibility. The ceramic balls were used as the meshing elements. Prototype of this research was made and tested with satisfying results. The results of this work are suitable for computeraided design and manufacture of industrial applications.
Authors: Bing Hai Lv, Ju Long Yuan, F. Cheng, Fan Yang
Abstract: Ceramic balls have become an important component in advanced bearings, and the sphericity of balls is a key qualification focused in lapping process. An investigation on the effect of dynamic behavior of ball support system on the performance of ball lapping in rotated dual-plates lapping method is carried out. Sinusoidal waveform in terms of Fourier analysis is employed to express the shape error of the ball surface, and a dynamic model for support is setup. It is found with numerical calculation that the variation of lapping load lags behind the variation of the shape error for the damping of support. A lower natural frequency of the support system, higher spin speed of balls and a larger value of spin angle in RDP lapping are better to rectify the shape error of balls and reduce the lagged effect. It is concluded that dynamics of lapping system must be taken into consideration in order to understand comprehensively the spherical surface generation mechanism.
Authors: Yu Hou Wu, Song Hua Li, Ke Zhang
Abstract: In resent years, ceramic balls have been applied into precision bearings and other parts far and wide because of its advantages in light weight, high hardness, abrasive resistance, high-temperature resistance, corrosion resistance, little heat expansion coefficient and so on. The high-precision ceramic balls are machined by lapping usually, and the method of lapping has an important influence on the machining precision and efficiency of ceramic balls. In order to improve the precision and efficiency of ceramic ball machining, in the paper, a new cone lapping method is researched by the lapping experiment. The research result shows that the cone method is the optimal lapping method with high precision, high efficiency and the very simple machine. Furthermore, the mechanics characteristic of the cone lapping method have been analyzed and summarized, which will provide the basic principle and theoretical basis for the choice of primary geometry and mechanics parameter in the process of ceramic balls lapping.
Authors: Ke Zhang, Yu Hou Wu, Shi Hong Li
Authors: Yu Hou Wu, Ke Zhang, H. Sun
Authors: Wen Xu Zhang, Cheng Zu Ren, F. Zheng, Xin Min Jin
Authors: Bing Hai Lv, Ju Long Yuan, Ying Xue Yao, Zhi Wei Wang
Abstract: To improve low lapping efficiency of silicon nitride balls in conventional lapping process, fixed abrasive lapping technology for ceramic balls is investigated in this paper. Diamond abrasives and photosensitive resin are used to fabricate the fixed abrasive plate. The lapped ball surface is observed with microscopy to identify the dominant wear mechanism. The results show that the material removal rate of the fixed abrasive lapping is about 20 times of that of conventional free abrasive lapping process, and the roughness is close to the conventional one. The experimental results indicate that the fixed abrasive lapping technology is a promising process to instead of conventional free abrasive lapping process for ceramic balls in rough and semi-finishing process.
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