ISSN   1004-0595

CN  62-1224/O4

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夏勇杰, 郭红, 李瑞珍, 石明辉, 陈岩. 多孔质可倾瓦推力轴承柔性枢轴结构设计和性能分析[J]. 摩擦学学报(中英文), 2024, 44(12): 1−10. doi: 10.16078/j.tribology.2023269
引用本文: 夏勇杰, 郭红, 李瑞珍, 石明辉, 陈岩. 多孔质可倾瓦推力轴承柔性枢轴结构设计和性能分析[J]. 摩擦学学报(中英文), 2024, 44(12): 1−10. doi: 10.16078/j.tribology.2023269
XIA Yongjie, GUO Hong, LI Ruizhen, SHI Minghui, CHEN Yan. Structural Design and Performance Analysis of Flexible Pivot for Porous Tilting Pad Thrust Bearings[J]. Tribology, 2024, 44(12): 1−10. doi: 10.16078/j.tribology.2023269
Citation: XIA Yongjie, GUO Hong, LI Ruizhen, SHI Minghui, CHEN Yan. Structural Design and Performance Analysis of Flexible Pivot for Porous Tilting Pad Thrust Bearings[J]. Tribology, 2024, 44(12): 1−10. doi: 10.16078/j.tribology.2023269

多孔质可倾瓦推力轴承柔性枢轴结构设计和性能分析

Structural Design and Performance Analysis of Flexible Pivot for Porous Tilting Pad Thrust Bearings

  • 摘要: 为进一步优化多孔质可倾瓦推力轴承结构,提升性能,提出并设计直梁形、弓形及混合形3种柔性枢轴形式的轴承并对其性能进行测试分析. 基于Darcy定律、N-S方程、流量平衡方程和瓦块运动方程等建立了多孔质可倾瓦气体推力轴承的静特性分析模型,并对不同柔性枢轴结构进行有限元分析,最后搭建了轴承静特性测试试验台. 研究了不同柔性枢轴结构及偏置对于轴承静特性的影响. 结果表明,弓形枢轴转动刚度最低、灵敏度最高,相同条件下瓦块的变形量最大,更适用于灵敏度要求高的场合;直梁形枢轴适用于承载力大的场合;混合形枢轴兼备了这2种结构的特点,适用于较高载荷以及较高灵敏度的场合;合理的枢轴偏置程度在一定程度上也能够提升轴承的性能. 理论与试验结果具有很好的一致性,从一定程度上验证了理论模型的合理性.

     

    Abstract: Due to the existing porous gas thrust bearings whose optimal working gas film clearance is usually in the micron order of magnitude, the machining and assembly error requirements for the bearings are extremely high in order to ensure the normal operation of the machine. The flexible pivot porous tilting pad gas thrust bearings use the adaptive ability of the flexible structure can reduce the machining and assembly accuracy requirements in some degree, as well as to compensate for the porous gas bearings of poor high-speed stability problems. However, its structure is single, and unable to meet more complex working conditions and a higher level of requirements. 【Objective】 In order to solve the above problems. The structure of porous tilting pad gas thrust bearing is optimized to improve its performance further. Three flexible pivot structures of bearings, which are the straight beam pivot, bow pivot and hybrid pivot, are proposed and designed for different applications. The bearing is made of integral aluminum alloy base and porous graphite material, adhered by epoxy resin. In order to ensure uniform air supply, a pressure equalizing groove structure is opened on the tilting pad. Choosing the right type of structure for different working conditions realizes a more stable operation of the rotor. 【Method】 Based on Darcy's law, N-S equation, flow balance equation, tile equation of motion and so on, the static characteristic analysis model of porous tilting pad gas thrust bearings was established. The equations of motion of the tilting pads considered the rotational stiffness calculation equations for different flexible pivot structures, as well as the model for calculating the tilt angle of the tilting pad. Finite element analysis was used to further examine the stresses as well as deformations of the bearings under different flexible pivot structures. The finite difference method and Newton's iterative method were used to solve the air film pressure, bearing capacity, and so on. Finally, comparing the theoretical calculation results of the model with the experimental results, the theoretical and experimental results were in good agreement, which verified the rationality of the theoretical model to a certain extent. 【Results】In the theoretical calculation of the rotational stiffness of three flexible pivot structures, the bow pivot structure had the smallest rotational stiffness of 7.08×104 Nmm/rad and the straight beam pivot structure had the largest of 1.13×106 Nmm/rad. And the finite element analysis results showed that the bow pivot structure had the maximum deformation and the maximum stress occurs at the minimum thickness of the pivot. When the external conditions were changed, the static characteristic parameters of the bearings under the bow pivot structure changed most significantly, followed by the hybrid pivot structure, and the straight beam pivot structure was the smallest. Theoretical and experimental results showed that the theoretical and experimental errors were within 10% of the levitation heights of the levitated materials under different structures when the external loads were 4.8 N and 9.8 N, respectively, and the air supply pressure was high. 【Conclusion】 The results showed that the bow pivot had the lowest rotational stiffness, the highest sensitivity and the largest deformation of pad under the same conditions, which was suitable for the occasions of lower load carrying capacity and higher sensitivity; the straight beam pivot was suitable for the occasions with large load capacity; the hybrid pivot combined the characteristics of these two structures, which was suitable for the occasions with high load and high sensitivity; the reasonable degree of pivot offset to a certain extent could also improve the performance of the bearings. Three different flexible pivot structures of bearings theoretical and experimental comparison results had proved the accuracy of the theoretical calculations.

     

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