Spiral Bearing Research Articles

Analyzing the impact of elastomer spiral bearings as seismic isolators in a reinforced concrete structure in Algeria

Over the past few years, Algeria has experienced numerous seismic events, particularly in the northern region of the country, due to its geographical position between the African and Eurasian tectonic plates. These earthquakes pose significant risks, leading to severe damage to both human life and property, including buildings and infrastructure. In response, civil engineers have increasingly advocated for the adoption of advanced seismic isolation techniques aimed at mitigating the transmission of seismic acceleration from the foundation to the superstructure. As a result, Algeria has seen the implementation of a few key projects incorporating seismic isolators, such as the Grand Mosque of Algiers. This article focuses on the design and analysis of the impact of typical aseismic elastomer spiral bearings in a reinforced concrete building located in the city of Oran, Algeria. The study utilizes ETABS software to evaluate the effectiveness of these bearings in enhancing the seismic resilience of the structure.

Calculation Method and Experimental Study on Circumferential Total Clearance of Cageless Bearings

This paper addresses the issue of the frequent collision and grinding of rolling elements in cageless bearings during operation by proposing a method to calculate the total circumferential clearance. The calculation is based on the maximum orbital speed difference in the bearing rolling elements to determine the minimum clearance needed to prevent collision. The study analyzes the impact of the rolling element diameter, bearing pitch diameter, contact angle, and number of rolling elements on the total circumferential clearance. The discussion then focuses on optimizing the number of rolling elements in cageless bearings. The optimization results demonstrate that the proposed calculation reduces collisions between rolling elements and bearing stress. Additionally, a total circumferential clearance test was conducted on a logarithmic spiral bearing, showing significant improvements in wear, average temperature, and temperature rise when designed according to the method presented in this article. These findings offer valuable insights into the design of cageless bearings.

Characteristics of Modified Spiral Thrust Bearing through Geometries and Dimension Modifications

This research focuses on the optimum design of fluid dynamic bearing (FDB) named modified spiral design. The objective is to improve the pressure and velocity distribution inside the FDB. In this paper, the current spiral design has 12 number of grooves while the modified spiral design has 24 number of grooves. Both design can be classified into two, bearing with seal and without seal. Air was chosen to replace the oil as the lubricant. Results show that the modified spiral bearing design has comparable characteristics compared to conventional spiral design in terms of pressure and velocity distribution. Modified spiral geometries also shows a tendency to replace the function of seals in FDB. This makes it possible to simplify bearing design without using any seal just by modifying its geometries based on novel modified spiral geometries. Experimental verifications also proved that the modified spiral bearing design has better air leakage control compared to the conventional ones. This phenomenon occurs in both design parameters, where when the designs are compared with respect to increase of rotational speed and air film thickness.

Spiral Bearing Lubrication with Viscosity Variation And Thermal Effect of Two Layer Fluid

In this paper a fluid film equation for two layer fluids and generalized Reynolds equation for convergent and divergent spiral bearing is derived with thermal effect. It is applied to see the effect of pre-load factor, viscosity variation, eccentricity, peripheral layer thickness. Expressions for load, pressure and coefficient of friction are derived and are analyzed numerically. The effect of pre-load factor analyzed for convergent and divergent spiral bearings. When pre-load factor is zero then both convergent and divergent spiral bearings are becomes journal bearing. It is observed the dimensionless load capacity values form the tables. The spiral bearing bears more load capacity than journal bearing. The effects of viscosity variation and thermal effect on these parameters are also analyzed.

Grease-lubricated spiral groove bearings

Small journal bearings, particularly those used in consumer goods, cannot usually be operated in the full-film lubrication regime. The new type of bearing described here has a combination of properties which may well make it possible to realize full-film lubrication with an oil-like medium in consumer articles, without the need for an oil reservoir and pump. For small bearing diameters it seems that grease lubricated spiral bearings have an important contribution to make to improvements in the life, reliability and performance of consumer goods, at an acceptable price.

Theory of a gas bearing with spiral grooves, taking account of the effects of slip and of local compressibility

The theory of a spiral bearing with a quasi-incompressible lubricant, proposed by Whipple [1], and expanded in [2–4], deviates from experimental investigations, particularly with large values of the compressibility parameter and intermediate values of the Knudsen numbers. Investigations carried out in simplified models of a spiral bearing [6, 7] have shown that the compressibility of a gas layer lowers its bearing capacity. This effect manifests itself even more strongly with intermediate values of the Knudsen number. Therefore, attempts to take account of the effect of slip within the framework of the theory of a quasi-incompressible layer [8] do not achieve their purpose. The proposed theory of a spiral bearing takes account of the combined influence of both effects, and is in agreement with experiment.