Axial Load Capacity of Water-Lubricated Hydrostatic Conical Bearings With Spiral Grooves (On the Case of Rigid Surface Bearings)
01 Oct 1996-Journal of Tribology-transactions of The Asme (American Society of Mechanical Engineers)-Vol. 118, Iss: 4, pp 893-899
TL;DR: In this paper, the static characteristics of water-lubricated hydrostatic conical bearings with spiral grooves were described and compared with experimental results. But the results were limited to high speed spindles.
Abstract: This paper describes the static characteristics of water-lubricated hydrostatic conical bearings with spiral grooves. Hydrostatic conical bearings treated here have been designed for high speed spindles and are intended to apply to spindles for drilling small holes of printed circuit-boards. Pressurized water is first fed to the inside of the rotating shaft and supplied to spiral grooves on the shaft surface through feeding holes. Therefore, water pressure is greatly increased at outlets of feeding holes due to the centrifugal force by shaft rotation. Furthermore, water pressure is also increased by the viscous pump effect of spiral grooves. Water pressures in the bearings under concentric condition are numerically obtained by using the finite element method and calculated results are compared with experimental ones. It is consequently found that this water-lubricated hydrostatic conical bearings with spiral grooves are very suitable for precision high speed spindles.
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01 Feb 2004
TL;DR: In this paper, the steady state and dynamic characteristics including whirl instability of water-lubricated journal bearings having three axial grooves are obtained theoretically. And the dynamic behaviour in terms of stiffness and damping coefficients of film and stability are found using a first-order perturbation method.
Abstract: The steady state and dynamic characteristics including whirl instability of water-lubricated journal bearings having three axial grooves are obtained theoretically. The Reynolds equation is solved numerically by the finite difference method satisfying the appropriate boundary conditions. The dynamic behaviour in terms of stiffness and damping coefficients of film and stability are found using a first-order perturbation method. It has been shown that both load capacity and stability improve when smaller groove angles are used.
53 citations
TL;DR: In this article, the static characteristics of a water-lubricated hydrostatic thrust bearing using a membrane restrictor were studied numerically and experimentally for a nonrotating shaft.
49 citations
TL;DR: In this article, the stability of water-lubricated, hydrostatic, conical bearing with spiral grooves for high-speed spindles is investigated theoretically and experimentally, and it was found that the proposed bearing is very stable at high speeds and theoretical predictions show good agreement with experimental data.
Abstract: In this paper, the stability of water-lubricated, hydrostatic, conical bearings with spiral grooves for high-speed spindles is investigated theoretically and experimentally. In these bearing types, pressurized water is first fed to the inside of the rotating shaft and then introduced into spiral grooves through feeding holes located at one end of each spiral groove. Therefore, water pressure is increased due to the effect of the centrifugal force at the outlets of the feeding holes, which results from shaft rotation. In addition, water pressure is also increased by the viscous pumping effect of the spiral grooves. The stability of the proposed bearing is theoretically predicted using the perturbation method, and calculated results are compared with experimental results. It was consequently found that the proposed bearing is very stable at high speeds and theoretical predictions show good agreement with experimental data.
44 citations
TL;DR: In this paper, the steady state and dynamic characteristics including whirl instability of oil journal bearings with single axial groove located at the top of the bearing and then at some angular interval from the top from which oil is supplied at constant pressure are obtained theoretically.
37 citations
TL;DR: In this paper, the load-carrying capacity, power losses and stiffness of disk-type hydrostatic thrust bearings including the case of eccentric loading are discussed theoretically based on a two-dimensional elastohydrostatic problem with an elastic deformation model, which is extended to adapt it for a non-axisymmetric load acting on the thrust bearing.
35 citations
References
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TL;DR: In this paper, a theoretical study of the characteristics of a multipad plane hydrostatic thrust bearing was made taking into account the effect of rotational lubricant inertia, and design data for the load capacity, flow and stiffness and damping characteristics were obtained for practically useful radius and resistance ratios for capillary and orifice compensation.
28 citations
18 citations
14 citations
TL;DR: In this article, the porous constant gap externally pressurized conical bearing was analyzed when the slider was rotating with uniform angular velocity and the lubricant was assumed to be incompressible, and its viscosity varies exponentially with temperature.
Abstract: The present paper analyzes the porous constant gap externally pressurized conical bearings when the slider is rotating with uniform angular velocity. The lubricant is assumed to be incompressible, and its viscosity varies exponentially with temperature. The lubricant inertia due to rotation of the slider is considered but the convective inertia is neglected. The energy equation is used to determine the temperature generated in the lubricant film. The governing system of coupled momentum and energy equation is solved numerically, using finite difference method, to determine various bearing characteristics. It is observed that for the surfaces which are highly porous the inlet pressure decreases remarkably, resulting in reduced load capacity of the bearing, and the torque remains unaffected with respect to variation in the permeability.
12 citations
TL;DR: Theoretical and experimental investigations of thermal and inertia effects on the performance of externally pressurized conical bearings are presented in this paper, where it is shown that the increase in oil temperature due to pad rotation has a detrimental effect on the load-carrying capacity but produces an increased flow rate.
12 citations