Showing papers on "Fluid bearing published in 1977"

Gas Lubricated Foil Bearing Development for Advanced Turbomachines

Abstract: : This document presents and discusses the design and development of gas lubricated foil journal and thrust bearings for the specific application in a 1000 to 3000 pound thrust propulsion engine. The design activity included the development of analytical tools for the thrust and journal bearings and their use during the bearing test phase, for the purpose of increasing bearing load capacity. A significant effort was spent toward materials and coating development for capabilities to 1200 F.

Fluid bearing including both hydrodynamic and hydrostatic bearings

Abstract: A fluid bearing for rotatably supporting a rotary shaft comprising a hydrodynamic bearing formed on a loaded side. A hydrostatic bearing is formed in axially juxtaposed relationship with the hydrodynamic bearing. An annular partition groove is formed between the hydrodynamic and hydrostatic bearings for supplying pressurized fluid from the hydrostatic bearing to the hydrodynamic bearing.

Fluid bearings with conforming shells

Abstract: A fluid bearing assembly includes a shaft mounted for rotation in a housing on a fluid film in a gap formed between the shaft surface and confronting surfaces on a plurality of shells mounted in the housing. The shells are relatively thick so that they bend in the manner of a stiff beam, and resilient supports are disposed between the shells and the housing which transmit fluid pressure forces on the shells to the housing and at the same time provide reaction loads on the shells which operate in pre-determined manner in opposition to changes in the fluid pressure forces to bend the shells to increase the load carrying capacity of the bearing.

High Efficiency Fluid Film Thrust Bearings For Turbomachinery

Abstract: Fluid film thrust bearings in use on high speed high capac­ ity turbomachinery absorb a great amount of energy in perform­ ing their task of positioning rotors. A review of thrust bearing fundamentals along with the latest design concepts briefly out­ line how thrust bearing performance can be substantially im­ proved. The major improvements come from selection of mate­ rials and methods of lubrication.

Experimental evaluation of foil-supported resilient-pad gas-lubricated thrust bearing

Abstract: A new type of resilient-pad gas thrust bearing was tested to determine the feasibility of the design The bearing consists of carbon graphite pads mounted asymmetrically on foil beams Two bearing configurations were tested at thrust loads from 27 to 80 newtons at speeds to 9000 rpm The outside diameter of the bearing was 89 centimeters

Optimization methods applied to hydrodynamic bearing design

Abstract: Optimization techniques are applied to the design of both hydrodynamic journal and tilting pad thrust bearings. Fletcher's adaptation of Davidon's gradient search method is further modified to deal with non-linear constraints in journal bearing design. A form of the Sequential Simplex is used for tilting pad thrust bearings. Penalty functions and variable transformations are used in both cases. Composite objective functions are included and the effect of weighting on each component of the composite function is investigated.

Performance of large-bore tapered-roller bearings under combined radial and thrust load at shaft speeds to 15,000 rpm

Abstract: The performance of 120.65-mm bore tapered roller bearings was investigated at shaft speeds up to 15,000 rpm. Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied by either jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.

Fluid bearing apparatus

Abstract: PURPOSE:The stabilization of the whole area of the desired rotation range for the thickness of the oil film between the bearing surfaces.

Ball to separator contact forces in angular contact ball bearings under thrust and radial loads

Abstract: Experimental data are reported on ball to cage contact forces in a 110 mm bore ball bearing operating at speeds to 12,000 rpm under radial and thrust loads. Information is also reported on cage to inner race land contact force, cage to inner race land clearance, and cage to shaft speed ratios.

Viscous shear fluid couplings

Abstract: The disclosure illustrates a viscous shear fluid fan drive comprising a driving disc received within an annular chamber of an output member. The disc and the chamber include closely spaced radially extending surfaces which transmit torque through a viscous fluid maintained between them. Pumping grooves are provided in the disc to insure rapid build up of hydrodynamic lubrication upon startup of the coupling. Cavities may be provided in the walls of the chamber to receive additional viscous fluid and extend service life of the coupling.

Static pressure fluid bearing

Abstract: PURPOSE:To obtain a static press. fluid bearing that prevents the loading of foreign matters to a throttle and does not cause the seizure of a shaft due to the loading.

Performance tests with a 4.75 inch bore tapered-roller bearings at high speeds

Abstract: The tapered-roller bearings were tested at speeds to 15,000 rpm which results in a cone-rib tangential velocity of 130 m/sec. (25,500 ft/min). Lubrication was applied either by jets or directly to the cone-rib, augmented with jets. Additional test parameters included thrust loads to 53,400 N (12,000 lbs), radial loads to 26,700 N (6,000 lbs), lubricant flow rates from 1.9 x 0.000 to 15.1 x 0.001 cubic meter/min. (0.5 to 4.0 gpm), and lubricant inlet temperatures of 350 K and 364 K (170 F and 195 F). Temperature distribution, separator speed, and drive-motor power demand were determined as functions of these test parameters.

The dual action gas thrust bearing - A new high load bearing concept

Abstract: The principle of utilizing hydrodynamic effects in diverging films for improving load capacity in gas thrust bearings is discussed. A new concept of dual action bearing based on that principle is described and analyzed. The potential of the new bearing is demonstrated both analytically for an infinitely long slider and by numerical solution for a flat sector shaped thrust bearing. It is shown that the dual action bearing can extend substantially the range of load carrying capacity in gas lubricated thrust bearings and improve their efficiency.

Efficiency of antiwear additives in greases for journal boxes of railroad cars

Abstract: Operating experience with railroad cars equipped with journal boxes with cylindrical roller bearings has shown that one of the most dangerous types of damage, leading to breakdowns and accidents, is wedging and spalling of the rollers and the rims of the races. The reported experiments were devoted to the study of antiwear properties of various additives in lubricating greases used in railroad cylindrical roller bearings. These studies were performed in a MT-TsNII laboratory friction tester which is shown schematically. In the first series of experiments, the critical load was determined, i.e., the highest load at which the coefficient of friction remained at the level of 0.3-0.5 during the entire course of the test run at this particular load step. Results are presented which show that, in obtaining reliable and breakdown-free operation of cylindrical roller bearings installed in rail-car journal boxes, the governing factor is found in those changes in friction-surface microgeometry occurring under the influence of the lubricating media in the process of sliding. There is every reason to believe that this index of lubricant properties must also be very important for other frictional assemblies in which the operating conditions permit short-term changeovers of hydrodynamic lubrication into boundary lubrication.