Theoretical analysis of compliance and dynamics quality of a lightly loaded aerostatic journal bearing with elastic orifices

Kodnyanko, Vladimir А.; Shatokhin, S. N.; Kurzakov, Andrey; Pikalov, Yuri

doi:10.1016/j.precisioneng.2020.11.012

Cited by 14 publications

(10 citation statements)

References 8 publications

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“…We also assume that the number of annular diaphragms in each row is large enough, which makes it possible to calculate the characteristics of the bearing by the method of continuous pressurization lines, which allows replacement discrete pressurization holes in each row with an equivalent continuous feeder with equal pressure at its outlet, while maintaining the nature of the flow of lubricant from the diaphragms [28]. Studies show that such a model is justified if the number of feeders in each row n k ≥ 12 [19]. In these cases, the error in calculating the performance of bearings with discrete feeders does not exceed 1%.…”

Section: Mathematical Modeling Of the Bearing Static State At Small Deviations Of The Moving Elements From The Central Equilibrium Positimentioning

confidence: 99%

“…To improve the static characteristics of radial bearings, two-row feeding systems and longitudinal microgrooves made in the inter-row zone are used, which practically exclude circumferential air leakage, and contributes to a significant increase in the load capacity [15][16][17]. To reduce compliance, aerostatic bearings with active air flow compensation are used, where inlet flow compensators; membrane regulators of the nozzle-damper type with throttles in the form of diaphragms with sharp edges and in the form of flat slots [18][19][20][21][22] or Laub elastic orifices, are used [23][24][25]. The use of inlet membrane or elastic regulators makes it possible to reduce the static compliance to zero and even negative values (in the latter case, the increments of the load and the bearing gap have the same signs).…”

Section: Introductionmentioning

confidence: 99%

“…This problem found a solution in the form of using an system of external combined throttling (SECT) containing the main throttling resistance, additional damping resistance and a flow-through air resonator chamber located between them, the optimal volume of which contributes to a drastic improvement in dynamic characteristics [26,27]. Diaphragms or elastic regulators act as the main resistance, and for damping resistance, annular diaphragms proved to be the best, the optimal resistance of which should be 5-15% of the total resistance of the SECT [19,28,29]. Such ratios of SECT resistances, in combination with the optimal volume of the throttle chamber, provide the best dynamics quality during the operation of bearings at almost any compliance, including zero and negative.…”

Section: Introductionmentioning

confidence: 99%

“…A more effective solution to reduce compliance is the use of compensators for displacement of the movable element (shaft) [18][19][20]. Such bearings also allow for a decrease in compliance to zero and negative values, which, like designs with membrane and elastic regulators, allows them to be used not only as supports, but also as active deformation compensators of the technological system of machine tools in order to reduce time and increase the accuracy of metalworking.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical Efficiency Study of Output Lubricant Flow Rate Regulating Principle on the Example of a Two-Row Aerostatic Journal Bearing with Longitudinal Microgrooves and a System of External Combined Throttling

et al. 2021

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Due to their vanishingly low air friction, high wear resistance, and environmental friendliness, aerostatic bearings are used in machines, machine tools, and devices that require high accuracy of micro-movement and positioning. The characteristic disadvantages of aerostatic bearings are low load capacity, high compliance and an increased tendency for instability. In radial bearings, it is possible to use longitudinal microgrooves, which practically exclude circumferential air leakage, and contributes to a significant increase in load-bearing capacity. To reduce compliance to zero and negative values, inlet diaphragm and elastic airflow regulators are used. Active flow compensation is inextricably linked to the problem of ensuring the stability of bearings due to the presence of relatively large volumes of gas in the regulator, which have a destabilizing effect. This problem was solved by using an external combined throttling system. Bearings with input flow regulators have a number of disadvantages-they are very energy-intensive and have an insufficiently stable load capacity. A more promising way to reduce compliance is the use of displacement compensators for the movable element. Such bearings also allow for a decrease in compliance to zero and negative values, which makes it possible to use them not only as supports, but also as active deformation compensators of the technological system of machine tools in order to reduce the time and increase the accuracy of metalworking. The new idea of using active flow compensators is to regulate the flow rate not at the inlet, but at the outlet of the air flow. This design has the energy efficiency that is inherent to a conventional bearing, but the regulation of the lubricant output flow allows the compliance to be reduced to zero and negative values. This article discusses the results of a theoretical study of the static and dynamic characteristics of a two-row radial aerostatic bearing with longitudinal microgrooves and an output flow regulator. Mathematical modeling and theoretical study of stationary modes have been carried out. Formulas for determining static compliance and load capacity are obtained. Iterative finite-difference methods for determining the dynamic characteristics of a structure are proposed. The calculation of dynamic quality criteria was carried out on the basis of the method of rational interpolation of the bearing transfer function, as a system with distributed parameters, developed by the authors. It was found that the volumes of the microgrooves do not have a noticeable effect on the bearing dynamics. It is shown that, in this design, the external combined throttling system is an effective means of maintaining stability and high dynamic quality of the design operating in the modes of low, zero and negative compliance.

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Section: Mathematical Modeling Of the Bearing Static State At Small Deviations Of The Moving Elements From The Central Equilibrium Positimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Theoretical Efficiency Study of Output Lubricant Flow Rate Regulating Principle on the Example of a Two-Row Aerostatic Journal Bearing with Longitudinal Microgrooves and a System of External Combined Throttling

et al. 2021

Self Cite

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“…It can be seen that at H d0 > 0.1 near the extremum points, there is a rapid increase in the values of the criterion ξ, which indicates a decrease in the oscillation of the system and, consequently, an increase in its damping. Already at H d0 > 0.2 for V k > V k,opt , where V k,opt is the volume corresponding to the maximum value of the stability degree η, the criterion ξ > 90%, which characterizes the bearing as a well-damped dynamic system [14,20,21].…”

Section: Dynamic Characteristics Of the Bearingmentioning

confidence: 99%

Dynamic Quality of an Aerostatic Thrust Bearing with a Microgroove and Support Center on Elastic Suspension

et al. 2021

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The disadvantage of aerostatic bearings is their low dynamic quality. The negative impact on the dynamic characteristics of the bearing is exerted by the volume of air contained in the bearing gap, pockets, and microgrooves located at the outlet of the feeding diaphragms. Reducing the volume of air in the flow path is a resource for increasing the dynamic quality of the aerostatic bearing. This article presents an improved design of an axial aerostatic bearing with simple diaphragms, an annular microgroove, and an elastic suspension of the movable center of the supporting disk. A mathematical model is presented and a methodology for calculating the static characteristics of a bearing and dynamic quality indicators is described. The calculations were carried out using dimensionless quantities, which made it possible to reduce the number of variable parameters. A new method for solving linearized and Laplace-transformed boundary value problems for transformants of air pressure dynamic functions in the bearing layer was applied, which made it possible to obtain a numerical solution of problems sufficient for practice accuracy. The optimization of the criteria for the dynamic quality of the bearing was carried out. It is shown that the use of an elastic suspension of the support center improves its dynamic characteristics by reducing the volume of compressed air in the bearing layer and choosing the optimal volume of the microgroove.

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Diagnostics of the Rotor-Stator Contact by Spectral Analysis of the Vibration State for Rotor Machines

Pavlenko

Savchenko

Piteľ

et al. 2021

Lecture Notes in Mechanical Engineering

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Theoretical analysis of compliance and dynamics quality of a lightly loaded aerostatic journal bearing with elastic orifices

Cited by 14 publications

References 8 publications

Theoretical Efficiency Study of Output Lubricant Flow Rate Regulating Principle on the Example of a Two-Row Aerostatic Journal Bearing with Longitudinal Microgrooves and a System of External Combined Throttling

Theoretical Efficiency Study of Output Lubricant Flow Rate Regulating Principle on the Example of a Two-Row Aerostatic Journal Bearing with Longitudinal Microgrooves and a System of External Combined Throttling

Dynamic Quality of an Aerostatic Thrust Bearing with a Microgroove and Support Center on Elastic Suspension

Diagnostics of the Rotor-Stator Contact by Spectral Analysis of the Vibration State for Rotor Machines

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