• Tribology and Lubricants
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• v.20 no.2
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• pp.68-76
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• 2004

Applying a general Galerkin FE lubrication analysis method to spiral groove dry gas seals, this study intends to analyze in detail the effects of groove design parameters, such as a spiral angle, groove width ratio, groove radius ratio, groove depth ratio, and groove taper ratio, on the lubrication performances of an opening force, leakage, axial stiffness and damping, and angular stiffness and damping at low and high rotating speeds: 3,600 and 15,000 nm. Results show that, for the primary design consideration performances such as the opening force and axial and angular stiffnesses, a spiral angle of $25^{\circ}$, a groove width ratio of 0.46, a groove radius ratio of 1.1, a groove depth ratio of 1.0, and a groove taper ratio of 0.0 are preferred. Where the recommended relatively low values of groove depth and taper ratios are to keep the axial and angular dampings positive or higher than 0 particularly at the high rotating speed.

• Tribology and Lubricants
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• v.28 no.6
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• pp.303-314
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• 2012

In this research, spool valves with spiral grooves are suggested and their lubrication characteristics are investigated by numerical analysis. The three-dimensional flow field is obtained by solving the Navier-Stokes equations in dimensionless form, so that the performance variables such as lateral force, friction force and volume flow rate are determined. Also, the lubrication characteristics of spool valves with spiral grooves are compared with those with typical grooves under variable working conditions. It is shown that spool valves with spiral grooves can get better performance in aspect of mitigation of uneven pressure distribution surrounding spool. Moreover, it is found that the minimum distance between spool edges and grooves, the type of spiral groove, and the groove angle have noticeable effect on the lubrication characteristics.

• Tribology and Lubricants
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• v.20 no.2
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• pp.58-67
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• 2004

In this study a general Galerkin FE lubrication analysis method for the compressible Reynolds equation in cylindrical coordinates is presented. Then, the method is applied for analyzing lubrication performances of spiral groove dry gas seals. The effects of toning and number of groove on performance indices are evaluated at low and high rotating speeds: 3,600 and 15,000 rpm. Results show that, for the primary design consideration performances such as the opening force and axial and angular stiffnesses, a negative or small coning and a large number of groove are preferred.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.235-242
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• 2000

In this paper, the dynamic characteristics of coupled herringbone groove journal bearings and spiral groove thrust bearings with conical motion were numerically analyzed, The bearing performance characteristics were calculated by the perturbation method and are solved by FDM. Stability of bearing was obtained from the threshold of instability.

• Tribology and Lubricants
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• v.18 no.3
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• pp.181-186
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• 2002

A numerical analysis is undertaken to show the influence of bearing design parameters on the load capacity of air lubricated spiral grooved thrust bearing. The governing equation derived from the mass balance is solved by the finite difference method. Optimal values for various design parameters are obtained to maximize the load capacity. The design parameters are the groove angle, the groove width ratio, the groove height ratio, and the seal ratio.

• Tribology and Lubricants
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• v.2 no.1
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• pp.30-38
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• 1986

In the paper, static characteristics of spiral grooved seal is theoretically obtained by Using Navier-Stokes equation. In the analysis, inertia term of fluid is considered and the flow and pressure in the steady state are obtained for the groove direction and vertical to the groove direction. As the journal rotating frequency increases, the leakage flow decreases. Therefore, zero net leakage flow is possible at the region of some rotating frequency.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1990.11a
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• pp.46-57
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• 1990

It is known that the effects of oil supply conditions on the characteristics of plain journal bearings are significant and especially the dynamic characteristics are affected by cavity region. For various shapes (axial groove, spiral groove, X-shape groove) and positions of oil grooves, the pressure distribution and the static performance of plain journal bearings are obtained with numerical methods. Elrods algorithm which implements JFO oil rupture/reformation boundary condition is used in order to take into account the effect of cavity region. It is shown that in the cases of axial groove or X-shape groove the load capacity and the attitude angle are affected by the groove position but the effect of spiral groove position is less significant.

• Tribology and Lubricants
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• v.6 no.2
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• pp.76-87
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• 1990

It is known that the effects of oil supply conditions on the characteristics of plain journal bearings are significant and especially the dynamic characteristics are affected by cavity region. For various shapes (axial groove, spiral groove, X-shape groove) and positions of oil grooves, the pressure distribution and the static performance of plain journal bearings are obtained with numerical methods. Elrods algorithm which implements JFO oil rupture/reformation boundary condition is used in order to take into account the effect of cavity region. It is shown that in the cases of axial groove or X-shape groove the load capacity and the attitude angle are affected by the groove position but the effect of spiral groove position is less significant.

• KSTLE International Journal
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• v.2 no.2
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• pp.93-102
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• 2001

Ball bearings have been widely used for the spindle motor bearing in various kinds of information storage devices. Recently many researchers have been trying to replace ball bearings with fluid film bearings because of their superior NRRO(non-repeatable runout) characteristics. In this study, a numerical analysis has been conducted for the complicate bearing system composed of herringbone groove journal bearing and spiral groove thrust bearing for the spindle motor of the information storage device. At first, spindle motor bearing is modeled as journal bearing part and thrust bearing part separately, and then observed various influences of geometric parameters. Previous studies had considered only the translational motion of the journal bearing. However, this study takes the additional 2-degree of freedom rotation into consideration to attempt to describe the real motion of the spindle bearing. As a result, rotational stiffness coefficients and rotational damping coefficients are obtained. In addition, a spindle bearing system made up of four bearings is modeled and interpreted at once and coefficients of dynamic characteristics of each bearing are obtained. Finally, an eigen analysis of bearing system is made with these results. Through this analysis, it is possible to estimate an unstable condition of the system for given geometric parameters and to propose a method which is able to avoid the unstable condition by a proper adjustment of geometric parameters.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.257-262
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• 2001

A numerical analysis is undertaken to show tile influence of bearing design parameters on tile load capacity of air lubricated spiral grooved thrust bearing. The governing equation derived from the mass balance is solved by the finite difference method. Optimal values for various design parameters are obtained to maximize the load capacity. The design parameters are the groove angle, the groove width ratio, the groove height ratio, arid the seal ratio.