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.

Analysis of water-lubricated journal bearings with multiple axial grooves:

Static characteristics of a water-lubricated hydrostatic thrust bearing using a membrane restrictor

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.

Stability of water-lubricated, hydrostatic, conical bearings with spiral grooves for high-speed spindles

Steady state and dynamic characteristics of axial grooved journal bearings

Characteristics of hydrostatic bearing/seal parts for water hydraulic pumps and motors. Part 2: On eccentric loading and power losses

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.

Y. Kakiuchi

Papers

Axial Load Capacity of Water-Lubricated Hydrostatic Conical Bearings With Spiral Grooves (On the Case of Rigid Surface Bearings)