Spherical Spiral Groove Bearings Research Articles

Stability Characteristics of Spherical Spiral Groove Bearings : 2nd Report, Experimental Study

We drive an expression of the lubricant film forces of spherical spiral groove bearings, taking the end effects into account. And we examine the effects of the finiteness of the number of grooves on the stability theoretically. theoretical solutions for load capacity and stability threshold are compared with experimental results. Experimental results are in good agreement with the theoretical ones. We obtain the conclusions as follows. The threshold of stability decreases as the number of grooves lessens. It is necessary to use the theoretical results in this paper in order to predict the threshold on such a bearing, the number of grooves of which is small (e.g. smaller than 5) and the spiral groove angle α of which is large (e.g. α> 30°). However, it is not necessary to consider the finiteness of the number of grooves on such bearings the number of grooves of which is more than 20.

Characteristics of Outwardly Pumping Spherical Spiral Groove Bearings : Part 1, Load Capacity

The static characteristics of outwardly pumping spherical spiral groove bearings are investigated. Solving the differential equation for a bearing which has an infinite number of grooves, we obtain the axial load capacity and the total liquid flow under radially concentric operating conditions. The effects of the bearing parameters on the load capacity and the liquid flow are examined. The experimental results are in good agreement with the theoretical ones. Although the axial load capacity of an outwardly pumping spherical spiral groove bearing is a fraction of that of an inwardly pumping one, and outwardly pumping spherical spiral groove bearing has enough load capacity.

Stability Characteristics of Spherical Spiral Groove Bearings : 2nd Report, Experiments

Stability Characteristics of Spherical Spiral Groove Bearings : 2nd Report, Experiments

Stability Characteristics of Spherical Spiral Groove Bearings : 1st Report, Theoretical Analysis

Stability Characteristics of Spherical Spiral Groove Bearings : 1st Report, Theoretical Analysis

Spherical and Conical Spiral Groove Bearings—Part I: Theory

The performance of spherical and conical spiral groove bearings lubricated with a Newtonian, incompressible liquid is investigated. This work covers both complete and incomplete filling of the bearing gap with a liquid. In an incompletely filled bearing gap a gas-to-liquid interface occurs. Under radially eccentric operating conditions the location of the interface is related to the pressure distribution in the lubricating film. Part I treats a theory based on the smooth pressure concept. A perturbation method serves to determine the pressure distribution and, in the case of an incompletely filled bearing gap, also the location of the gas-to-liquid interface. From the pressure distributions, different for the two cases, formulas have been derived for the radial and axial load capacity. Comparison of the results obtained with this perturbation method with the results obtained with a numerical method lead to the conclusion that the former results can be used in practice as long as practically no cavitation occurs in the bearing. Previously reported experiments with spiral groove journal bearings confirm this. In spiral groove bearings the groove dimensions which lead to a satisfactory operation of the bearing are generally such that even with fairly marked eccentricities there is practically no occurrence of cavitation. Part II will treat the results obtained with the theory of Part I.