The Dynamic Stiffness of Controlled Hydrostatic Bearings

Mohsin, M. Ezzat; Morsi, S. A.

doi:10.1115/1.3555006

Cited by 23 publications

(10 citation statements)

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“…Furthermore, the use of active bearings, e.g. magnetic bearing [1], active air and oil bearings [2,3], is increasing in order to improve the performance of rotating machinery. Since the performance of these systems is therefore directly affected by the quality of the sensor signal, accurate measurement of the spindle error motion is critical.…”

Section: Introductionmentioning

confidence: 99%

Optimal multi-segment cylindrical capacitive sensor

Ahn

Han

2003

Meas. Sci. Technol.

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This paper discusses a multi-segment cylindrical capacitive sensor (CCS) optimized to minimize the effects of geometric errors. Spindle error motion is a key index of performance in rotating machines. The CCS was developed as an alternative of probe-type sensors and applied to several rotating machine applications since the spindle error motion can be measured accurately without a significant effect of geometric errors. However, research on the CCS has so far focused on the case of two pairs of sensor units. Therefore, it is necessary to investigate the general case or multi-segment CCS for a better rejection of geometric errors. This work presents generalization of the previous CCS system down to a multi-segment CCS. We first introduce a multi-segment CCS that consists of equally spaced pairs of sensor units of the same angular size on the circumference, and derive a mathematical model of the measuring process with the multi-segment CCS. Theoretical analysis using the mathematical model shows that a multi-segment CCS with n pairs of sensor units can remove all harmonic errors except the (2nk − 1)th and (2nk + 1)th (k = 1, 2, 3, . . .) harmonic errors. In addition, the angular size of the multi-segment CCS is optimized to minimize the effects of geometric errors through a minimum norm approach. The optimal multi-segment CCS with n pairs of sensor units has the largest sensor unit size among those which remove the (2n − 1)th harmonic error, which is the lowest harmonic error that cannot be removed with n sensor unit pairs.

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Section: Introductionmentioning

confidence: 99%

Optimal multi-segment cylindrical capacitive sensor

Ahn

Han

2003

Meas. Sci. Technol.

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“…Cusano 17 analytically studied the four recesses circular journal bearing using variable flow membrane restrictor and observed improvement in bearing load carrying capacity. Mohsin and Morsi 21 studied analytically and experimentally hydrostatic circular bearing system using variable flow-type restrictor and observed enhancement in values of fluid-film coefficients. Kang et al 22 and Gohara et al 23 studied the hydrostatic circular thrust bearing using membrane restrictor as compensating device.…”

Section: Introductionmentioning

confidence: 99%

Finite element analysis of multirecess hybrid spherical journal bearing system

Tomar

Sharma

2019

Proceedings of the Institution of Mechanical Engineers, Part J:

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The present work deals with finite element method analysis of a multirecess hybrid spherical journal bearing system. The governing equations have been discretized using Galerkin’s technique and are solved simultaneously using a suitable iterative technique. The effect of span angle on the static and dynamic behavior of a hybrid spherical journal bearing compensated with membrane restrictor is investigated in the present work. Numerical results indicate that larger values of span angle provide enhanced value of minimum fluid-film thickness [Formula: see text], reduced lubricant flow requirement [Formula: see text], and higher value of frictional torque [Formula: see text]. Further, the results have been compared with a correspondingly similar capillary-compensated bearing. The comparison of numerically results demonstrates that the value of direct fluid-film stiffness coefficient [Formula: see text] could be 45.90% higher than that of correspondingly similar capillary-compensated bearing. The numerical results presented in this work may be useful as design guidelines for a recessed hybrid spherical journal bearing.

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“…Though in the past, cheap and standardized rolling bearings that have superior replaceability were used as a method for the precision of the spindle and maintaining its rigidity in high speed rotation, it is said that rolling bearing is vulnerable to friction between metal pieces, thermal deformation caused by heat, and vibration. Accordingly, hydrostatic bearings are essentially used for the spindle of a machine tool as an alternative, which has an advantage that it can maintain high precision and stiffness with no abrasion since only viscous friction of fluid left as solid friction is eliminated by the hydraulic pressure that is formed between the journal bearing and the spindle [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

A Study on the Thermal Characteristics of the Grinding Machine Applied Hydrostatic Bearing

Kim¹,

Bae²,

Kim³

et al. 2015

Transactions of the Canadian Society for Mechanical Engineering

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In order to activate the high precision and multi-functional machine tool, adequate technical level of the high-precision products is required. The hydrostatic bearings is used as a method for producing the high-precision products. The hydrostatic bearing has a relatively small run-out compared to its shape error by fluid film effect in hydrostatic state similar to pneumatic bearing and has high stiffness, load capacity and damping characteristics. In this study, we conducted a study on the thermal deformation of the grinding machine that has a great influence on the machining accuracy of the product. The temperature of the front bearing is 10°C or higher than the temperature of the rear bearing. Thermal deformation of the spindle was found to be dependent on the temperature of the hydrostatic bearing and could identify the overall thermal characteristics of the grinding machine.

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The Dynamic Stiffness of Controlled Hydrostatic Bearings

Cited by 23 publications

References 0 publications

Optimal multi-segment cylindrical capacitive sensor

Optimal multi-segment cylindrical capacitive sensor

Finite element analysis of multirecess hybrid spherical journal bearing system

A Study on the Thermal Characteristics of the Grinding Machine Applied Hydrostatic Bearing

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