Theoretical and Experimental Investigation of an Externally Pressurized Porous Annular Thrust Gas Bearing and Its Optimal Design

Cui, Changzhi; Ono, Kyosuke

doi:10.1115/1.2833524

Cited by 12 publications

(4 citation statements)

References 13 publications

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“…The exceptional advantages of aerostatic bearings are the high rotation speed and extremely low friction [1][2][3][4][5]. The bearings are lubricated with compressed gas from the source into the flow path, which usually uses passive elements to limit the gas flow to create a certain pressure which is necessary to maintain the current load and to control the displacement of the moving part of the structure, thereby ensuring its stiffness [4][5][6][7][8][9][10][11][12][13][14][15][16]. And although the development of technology has contributed to the improvement of bearings, they still have a drawback-low stiffness [8,10,17,18].…”

Section: Introductionmentioning

confidence: 99%

Mathematical Modeling on Statics and Dynamics of Aerostatic Thrust Bearing with External Combined Throttling and Elastic Orifice Fluid Flow Regulation

et al. 2020

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As aerostatic bearings are used in high-speed metal-cutting machines to increase machining accuracy, there is the need to improve their characteristics, including compliance, which is usually high. In practical applications, a significant reduction of bearing compliance is often necessary, sometimes down to zero and even negative values, to ensure automatic compensation of the elastic deformation in the machine technological system. A decrease in compliance leads to deterioration in the dynamic performance of the bearing, so it is necessary to develop new designs that meet the above requirements. This article considers an aerostatic bearing, in which decrease in compliance is ensured by the use of air throttling with elastic orifices. To ensure its stability, the principle of combined external throttling was applied, which can substantially improve the dynamics of conventional aerostatic bearings. A mathematical model of the elastic orifice deformation was developed, together with the flow rate performance calculation method. The method ensured full qualitative and satisfactory quantitative agreement with the experimental data. The model was used in the mathematical modeling of the aerostatic bearing movement. The article also proposes a method to calculate the static load capacity and compliance of a bearing, as well as a numerical method for fast computation of its dynamic performance, which allows for real-time multi-parameter optimization by the bearing dynamic performance criteria. The study showed that there is an optimal set of design parameters for which low, zero, and negative static compliance of the bearing is ensured, with the necessary stability margin, high speed, and the non-oscillatory nature of the transient processes.

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Section: Introductionmentioning

confidence: 99%

Mathematical Modeling on Statics and Dynamics of Aerostatic Thrust Bearing with External Combined Throttling and Elastic Orifice Fluid Flow Regulation

et al. 2020

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“…Some properties of aerostatic bearings are low friction, precise rotation, and ultra-precision. In order to fulfil the needs for enhanced performance in associated sectors such as semiconductors, defence, microelectronic, textile, aerospace, and measuring instruments, extensive research has been undertaken on the performance of aerostatic thrust bearing [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Design and Development of Different Applications of PATB (Porous Aerostatic Thrust Bearing): A Review

CHAKRABORTY,

CHAKRABORTI

2023

Finnish J. Trib.

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In several applications demanding precise and ultra-precision movements, porous aerostatic thrust bearings had been employed as a crucial precision engineering component and enabling technology. By acting as a lubricant between the moving part and the stationary part in aerostatic bearings, pressurized air almost completely eliminates friction. Since air acts as the lubricant, oil-based lubricants leave no debris behind. The air prolongs the life of the substances by preventing them from slipping and wearing. The aerostatic type uses graphite as a porous film to disrupt the air uniformly over the surface, or a tiny hole is drilled through the centre of the bearing to let the air circulate and produce a thin layer between the components. With an increased reliance on computational and mathematical methodologies for design and bearing performance optimization, this review paper aims to present the state-of-the-art in aerostatic bearings advancement and research. It also conducts a critical analysis of their future research directions and development trends in the next ten years and beyond. Air bearings are utilized in the production of tools like lathes, CMM, and grinders because they are highly precise in their operation and decrease mistakes and production time. Air bearings are available in a variety of forms and sizes. The assessment of future trends and obstacles in aerostatic bearings investigation, as well as their prospective applications in the precision engineering sectors, concludes the study.

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“…They showed the load-carrying capacity with respect to the eccentricity ratio by using the perturbation method, and also showed the pressure distribution in a porous material for the concentric condition. Cue and Ono [10] treated the static and dynamic characteristics of aerostatic porous annular thrust bearings with a restricted layer. They also applied Darcy's law to a restricted layer and presented the optimum design method for this type of bearing.…”

Section: Introductionmentioning

confidence: 99%

“…Yoshimoto and Kohno [11] studied the static and dynamic characteristics of aerostatic circular thrust bearings with a restricted layer and clari®ed the effect of air supply area on these characteristics. Experimental results presented in references [10] and [11] were obtained by using graphite as the porous material, which has generally a lower permeability than porous metal.…”

Section: Introductionmentioning

confidence: 99%

Static characteristics of aerostatic porous journal bearings with a surface-restricted layer

Yoshimoto

Tozuka

Dambara

2003

Proceedings of the Institution of Mechanical Engineers, Part J:

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Graphite porous materials have been successfully used in an aerostatic bearing. This is because graphite porous materials have a lower permeability than porous metal, which makes it possible to achieve a higher stiffness in aerostatic bearings. However, aerostatic porous bearings have a disadvantage in that they are prone to cause pneumatic hammer instability. Therefore, a restricted layer which has a permeability lower than the bulk of the porous material is usually formed on the bearing surface to avoid this instability. In this paper, the static characteristics of aerostatic porous journal bearings with a surface-restricted layer are investigated theoretically and experimentally. In addition, the effects of a surface-restricted layer on the static characteristics are discussed for two types of loads, symmetrical and coupled. NOTATIONe c shaft displacement at the bearing end for coupled loads (m) e s shaft displacement for symmetrical loads (m) dr s thickness of a surface-restricted layer (m) ds thickness of end seal (m) D diameter of the shaft (m) h local bearing clearance (m) h 0 average bearing clearance (m) k permeability of the bulk of porous material (m 2 ) k 0 permeability of a restricted layer (m 2 ) L bearing length (m) L 1 width of circumferential air supply groove (m) m tilt moment (N m) M dimensionless tilt moment h 0 m= …p s ¡ p a †DL 2 £ ¤ p a ambient pressure (Pa) p s supply pressure (Pa) p 1 , p 2 pressures in porous material and bearing clearance (Pa) P dimensionless pressureˆ…p ¡ p a †=p a q mass¯owrate (kg/s) q r , q z , q y mass¯owrates in the r, z, y directions (kg/s) q v volume¯owrate (m 3 /s) Q mass¯ow reduction ratio r, z, y coordinates in the r, z, y directions r s radial thickness of porous material (m) r 0 radius of the bearing (m) r 1 outer radius of porous material (m) < gas constant T temperature (K) w load-carrying capacity (N) W dimensionless load-carrying capacitŷ w= …p s ¡ p a †DL ‰ Š Z dimensionless coordinate in the z directionˆz=L a parameter pertaining to a surface restrictorˆ…k 0 /k †/…dr s /r s † e c eccentricity ratio at the bearing end for coupled loadsˆe c L/…2h 0 † e s eccentricity ratio for symmetrical loadsˆe s /h 0 r 1 , r 2 densities of air in porous material and bearing clearance (kg/m 3 )

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Theoretical and Experimental Investigation of an Externally Pressurized Porous Annular Thrust Gas Bearing and Its Optimal Design

Cited by 12 publications

References 13 publications

Mathematical Modeling on Statics and Dynamics of Aerostatic Thrust Bearing with External Combined Throttling and Elastic Orifice Fluid Flow Regulation

Mathematical Modeling on Statics and Dynamics of Aerostatic Thrust Bearing with External Combined Throttling and Elastic Orifice Fluid Flow Regulation

Design and Development of Different Applications of PATB (Porous Aerostatic Thrust Bearing): A Review

Static characteristics of aerostatic porous journal bearings with a surface-restricted layer

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