Structural Stiffness and Damping Coefficients of a Multileaf Foil Bearing With Bump Foils Underneath

Tian, Ye; Sun, Yanjing; Yu, Lie

doi:10.1115/1.4026054

Cited by 10 publications

(7 citation statements)

References 23 publications

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“…Figure 1(a) shows the relative position of the foils of a four pads radial bearing before pre-tightening assembly. 17 The diameter of the top foil is bigger than the bearing sleeve. However, after assembly, the top foils are overlapped evenly along the inner surface of the bearing sleeve.…”

Section: Multi-leaf Foil Bearingmentioning

confidence: 99%

The shape error evaluation methods of the foils for a multi-leaf foil bearing

Ren

Sun

2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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The geometric parameters of the elastic foil bearing are important basis for designing the foil bearing. Whether the main shape indices of the pressed foils meet the design requirements is the key to evaluate a manufacturing method. The inconsistent curvature radii of the top foils, the inconsistent bump heights of the bumps on the bump foil, the roundness error of the top foil, and the curve profile error of the bump foil may cause the pre-tightening assembly difference and different bearing capacity of each bearing shell. Aiming at the shape error evaluations of the foils for a multi-leaf foil bearing, first, the algorithm of geometric area optimization for circle roundness error is introduced and an evaluation method of arc roundness error is put forward according to the minimum zone principle in this paper. This method can be used to calculate the roundness error of the top foil for a multi-leaf foil bearing. The results show that the corresponding roundness error of the top foil decreases with the increasing of the pressing pressure. The relative roundness error is small (less than 7%), which changes a little with different pressing pressures. For the measurement of a bottom bump foil, the method of matching feature points is used in pre-location and then fine-positioning for the measured curve is implemented based on the least square method in order to eliminate the position error between the measured curve and the design curve. Thus, the curve profile error evaluation of the bottom bump foil for a multi-leaf foil bearing is implemented and the profile error of each bump can be obtained. According to the shape error evaluation values of the top foil and the bump foil, the quality control strategy and the error compensation by improving the mold structure can be further researched.

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Section: Multi-leaf Foil Bearingmentioning

confidence: 99%

The shape error evaluation methods of the foils for a multi-leaf foil bearing

Ren

Sun

2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Liu et al (30,31) extended this structure to the oil-lubricated multileaf foil bearing and built up a test rig to verify the theoretical investigation. Tian et al (32) conducted the static and dynamic load tests under conditions of non-spinning shaft with different excitation frequency. The measurements can serve for the calibration of analytical tools.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Area Contact on the Static Performance of Multileaf Foil Bearings

Zhu

et al. 2015

Tribology Transactions

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For multileaf foil bearings，the interactions between adjacent foils, foils and gas film are key to predict the bearing performance. However, most of the analytical models were based on line contact rather than area contact between adjacent foils and the latter may occur and play an important role in load capacity. In this study, the curved beam model is adopted to build up the elastohydrodynamic model considering the area contact between adjacent foils, which is solved iteratively coupling the Reynolds equation by the finite element method. An algorithm is developed to judge and determine the contact condition of adjacent foils. The simulation results show that the area contact between adjacent foils does occur and the contact area expands with the increasing of eccentricity ratios and rotational speeds, which make the film thickness distribution smooth and are beneficial to the increase of load capacity. The area contact occurs near the trailing end of the foils first, and then gradually expands. The later formed contact area bears greater load capacity instead of the early formed contact area, and the load capacity is mainly provided by the gas film on the foils with more area contact.

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“…Generally, there are two ways to increase the damping of GFBs: by increasing Coulomb friction damping and by increasing material internal damping. For the former, a multilayer 9 or multileaf 10,11 foil structure can be used; for the latter, a metal mesh 12 or a vibration damper component 13 can be introduced. Moreover, threepad GFBs 6,14,15 and three-pad bidirectional GFBs 16 have been developed to further increase the stability of bearing-rotor systems.…”

Section: Introductionmentioning

confidence: 99%

Rotor dynamic experimental investigation of an ultra-high-speed permanent magnet synchronous motor supported on a three-pad bidirectional gas foil bearing

Cheng

Deng

Xiao

et al. 2019

Advances in Mechanical Engineering

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With a 10-kW, 120,000-r/min, ultra-high-speed permanent magnet synchronous motor taken as a prototype, experimental research is conducted on the rotor dynamic behaviours of a three-pad bidirectional gas foil bearing high-speed motor rotor system. Load-carrying properties of the three-pad bidirectional gas foil bearing are analysed, and natural frequencies of conical and parallel whirling modes of the elastically supported rotor are calculated based on an appropriate simplification to the stiffness and damping coefficients of the gas foil bearings. The prototype passes through a 90,000-r/min coast-down experiment. Experiments show that there are violent subsynchronous whirling motions that are evoked by the gas foil bearing–rotor system itself. The cause of shaft orbit drift is analysed, and the corresponding solution is put forward. The theoretical analysis and experimental results can offer a useful reference to the bearing–rotor system design of ultra-high-speed permanent magnet motors and its subsequent dynamic analysis.

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Structural Stiffness and Damping Coefficients of a Multileaf Foil Bearing With Bump Foils Underneath

Cited by 10 publications

References 23 publications

The shape error evaluation methods of the foils for a multi-leaf foil bearing

The shape error evaluation methods of the foils for a multi-leaf foil bearing

The Effect of Area Contact on the Static Performance of Multileaf Foil Bearings

Rotor dynamic experimental investigation of an ultra-high-speed permanent magnet synchronous motor supported on a three-pad bidirectional gas foil bearing

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