Thrust bearing

A gas lubricated thrust bearing is described which employs relatively rigid inwardly cantilevered spokes carrying a relatively resilient annular member or annulus. This annulus acts as a beam on which are mounted bearing pads. The resilience of the beam mount causes the pads to accept the load and, with proper design, responds to a rotating thrust-transmitting collar by creating a gas film between the pads and the thrust collar. The bearing may be arranged for load equalization thereby avoiding the necessity of gimbal mounts or the like for the bearing. It may also be arranged to respond to rotation in one or both directions

Solenoid valve design has one moving part

Solenoid valve structure has only one moving part, a ball and spring assembly. This eliminates wear caused by sliding motion contact between stationary and moving parts or between moving parts

High speed hybrid bearing comprising a fluid bearing and a rolling bearing convected in series

A description is given of an antifriction bearing and a process by which its fatigue life may be extended. The method involves a rotating shaft supported by a fluid bearing and a rolling element bearing coupled in series. Each bearing turns at a fraction of the rotational speed of the shaft. The fluid bearing is preferably conical, thereby providing thrust and radial load support in a single bearing structure

Analysis of an all-metallic resilient-pad gas-lubricated thrust bearing

A resilient-pad gas thrust bearing that does not contain any elastomers in the bearing assembly is described and analyzed. The bearing consists of sector-shaped pads mounted asymmetrically on resilient foil beams. The effects of bearing design parameters on performance are shown. Performance of a resilient-pad bearing is compared with that of a pivoted-pad bearing

Analysis of the dynamics of a nutating body

The equations for the displacement, velocity, and acceleration of a point in a nutating body are developed. These are used to derive equations for the inertial moment developed by a nutating body of arbitrary shape. Calculations made for a previously designed nutating plate transmission indicate that that device is severely speed limited because of the very high magnitude inertial moment

Bearings: Technology and needs

A brief status report on bearing technology and present and near-term future problems that warrant research support is presented. For rolling element bearings a material with improved fracture toughness, life data in the low Lambda region, a comprehensive failure theory verified by life data and incorporated into dynamic analyses, and an improved corrosion resistant alloy are perceived as important needs. For hydrodynamic bearings better definition of cavitation boundaries and pressure distributions for squeeze film dampers, and geometry optimization for minimum power loss in turbulent film bearings are needed. For gas film bearings, foil bearing geometries that form more nearly optimum film shapes for maximum load capacity, and more effective surface protective coatings for high temperature operation are needed

The practical impact of elastohydrodynamic lubrication

The use of elastohydrodynamics in the analysis of rolling element bearings is discussed. Relationships for minimum film thickness and tractive force were incorporated into computer codes and used for bearing performance prediction. The lambda parameter (ratio of film thickness to composite surface roughness) was shown to be important in predicting bearing life and failure mode. Results indicate that at values of lambda below 3 failure modes other than the classic subsurface initiated fatigue can occur

The specific heat jump at the superconducting transition and the quantum critical nature of the normal state of Pnictide superconductors

Recently it was discovered that the jump in the specific heat at the superconducting transition in pnictide superconductors is proportional to the superconducting transition temperature to the third power, with the superconducting transition temperature varying from 2 to 25 Kelvin including underdoped and overdoped cases. Relying on standard scaling notions for the thermodynamics of strongly interacting quantum critical states, it is pointed out that this behavior is consistent with a normal state that is a quantum critical metal undergoing a pairing instability.Comment: 4 pages 1 figur

The origin of phase in the interference of Bose-Einstein condensates

We consider the interference of two overlapping ideal Bose-Einstein condensates. The usual description of this phenomenon involves the introduction of a so-called condensate wave functions having a definite phase. We investigate the origin of this phase and the theoretical basis of treating interference. It is possible to construct a phase state, for which the particle number is uncertain, but phase is known. However, how one would prepare such a state before an experiment is not obvious. We show that a phase can also arise from experiments using condensates in Fock states, that is, having known particle numbers. Analysis of measurements in such states also gives us a prescription for preparing phase states. The connection of this procedure to questions of ``spontaneously broken gauge symmetry'' and to ``hidden variables'' is mentioned.Comment: 22 pages 4 figure

Rim inertial measuring system

The invention includes an angular momentum control device (AMCD) having a rim and several magnetic bearing stations. The AMCD is in a strapped down position on a spacecraft. Each magnetic bearing station comprises means, including an axial position sensor, for controlling the position of the rim in the axial direction; and means, including a radial position sensor, for controlling the position of the rim in the radial direction. A first computer receives the signals from all the axial position sensors and computes the angular rates about first and second mutually perpendicular axes in the plane of the rim and computes the linear acceleration along a third axis perpendicular to the first and second axes. A second computer receives the signals from all the radial position sensors and computes the linear accelerations along the first and second axes