Showing papers on "Bearing (mechanical) published in 1969"

Stochastic Models for Hydrodynamic Lubrication of Rough Surfaces

Abstract: This paper deals with hydrodynamic aspects of rough bearing surfaces. On the basis of stochastic theory two different forms of Reynolds-type equation corresponding to two different types of surface roughnesses are developed.It is shown that the mathematical form of these equations is similar but not identical to the form of the Reynolds equation governing the behaviour of smooth, deterministic bearing surfaces.To illustrate the functional effects of surface roughness the influence on the operating characteristics of a plane pad, no side leakage slider bearing is analysed.It is shown that surface roughness may considerably influence the operating characteristics of bearings and that the direction of the influence depends upon the type of roughness assumed. The effects are not, however, critically dependent upon the detailed form of the distribution function of the roughness heights.

Effects of Hydraulic Forces in Annular Pressure Seals on the Vibrations of Centrifugal Pump Rotors

Abstract: In centrifugal pumps, the annular clearance spaces of the leakage path, i.e. impeller seals and balance piston seals, act as powerful hydrostatic bearings with turbulent flow. In the present discussion, the dynamic forces due to these bearings acting on the rotor are analysed, including the effect of squeeze action, i.e. the effect of velocities of separation or approach of the bearing and journal surfaces.Synchronous forced whirling is analysed in a simple idealization comprising a single mass rotor, including the estimation of amplitudes as well as critical speeds. Large damping forces due to squeeze action are found, in qualitative agreement with experimental work by Marcinkowskij and Karincev (3)†. A simplified treatment of the effects of fluid rotation is included in the analysis of rotor vibrations, leading to an analysis of high speed whip instability onset.

Self-pressurizing bearings with resilient elements

Abstract: A hydrodynamic fluid bearing is disclosed having a deflectable resilient bearing element within the spacing formed between the movable and stationary portions of the bearing. Additionally, resilient bearing stiffeners are positioned immediately adjacent the bearing element for changing in a predetermined way the deflection response of the bearing element. In order to initiate bearing element deformation a groove is formed in the bearing element. Deformation of the bearing element is controlled by support elements positioned between the resilient bearing element and the stationary portion of the bearing.

Bottom bracket for bicycle

Abstract: A bottom bracket for bicycle having a pair of ball bearings for supporting a crankshaft, at least one of the bearings having an inner race slidable with respect to the crankshaft, and a coil spring urging the inner race of said one bearing against the steel balls to avoid chattering of the elements due to localized or irregular wear which would otherwise be produced on these members thereby to facilitate smooth rotation of the crankshaft

Resilient bearing mounting

Abstract: An elastomeric pad positioned between the bearing assembly and the load bearing portion of a railway truck side frame. The pad is deformed when the truck negotiates a curve to accommodate a nonparallel condition of the axles and thereby avoid slippage between the wheels with respect to the rails. The elastomeric element is stressed during such displacement of a truck axle and this energy serves to restore the axle to a position at right angles to the track when the truck proceeds onto a track section which is tangent to the curve.

Containers for liquefied gases

Abstract: A large-scale self-supporting insulated metal tank for cryogenic fluids such as liquid natural gas, in which the insulation lining the bottom of the tank has spaced sections of expensive loadbearing material capable of bearing the load of the filled tank under working conditions, with relatively inexpensive non-loadbearing insulation filling the bottom spaces between the sections of load-bearing insulation

Discussion of theoretical bearing capacity of very shallow footings

Abstract: THE REASON WAS INVESTIGATED FOR THE DISCREPANCY IN THE BEARING CAPACITY RESULTS OBTAINED BY THE AUTHOR AND IN OTHER STUDIES THE AUTHOR TAKES THE SHEAR STRENGTH OF THE SOIL ABOVE FOUNDATION LEVEL INTO ACCOUNT, BUT ACCORDING TO A PRESENTED FIGURE, THE RANKINE ZONE IS SIMPLY EXTENDED ABOVE THIS LEVEL, AND IT IS ALSO IMPLIED THAT A PASSIVE EARTH PRESSURE CORRESPONDING TO A PERFECTLY SMOOTH WALL IS ACTING ON EACH OF THE TWO VERTICAL FACES AB OF THE FOOTING THIS PROBLEM IS UNDER STUDY AT THE DANISH GEOTECHNICAL INSTITUTE THE THEORETICAL CALCULATION OF BEARING CAPACITIES FOR CIRCULAR FOOTINGS ARE OPEN TO DOUBT ON TWO POINTS WHICH ARE DISCUSSED THE HAAR AND VON KARMAN HYPOTHESIS IS INCOMPATIBLE WITH THE PROPORTIONALITY BETWEEN THE PLASTIC STRAIN AND THE DEVIATOR STRESS TENSORS POSTULATED BY REUSS, AND THE USE OF THE HAAR AND VON KARMAN HYPOTHESIS IMPLIES THAT THE FRICTION ANGLES FOR WHICH THE AVERAGE BEARING PRESSURES ARE CALCULATED ARE THOSE CORRESPONDING TO A TRIAXIAL STATE OF STRAIN MR KARAFIATH COMMENDS THE NUMERICAL METHOD USED BY THE AUTHOR TO INVESTIGATE THE THEORETICAL BEARING CAPACITY OF SHALLOW FOOTINGS IT IS RECOMMENDED THAT THE COMPUTER PROGRAM BE ADAPTED TO VARIOUS BOUNDARY CONDITIONS, AS THE AUTHOR ADAPTED THE METHOD TO INCLUDE THE SOIL ABOVE THE BASE OF THE FOOTING IN THE SLIP LINE FIELD RATHER THAN CONSIDERING IT AS A SURCHARGE THE WRITER AGREES WITH THE AUTHOR THAT OTHER FACTORS, SUCH AS ROUGHNESS OF THE FOOTING, ALSO HAVE SIGNIFICANT INFLUENCES ON BEARING CAPACITY THIS EFFECT MAY BE EASILY INVESTIGATED BY THE NUMERICAL METHOD REFERENCES: THEORETICAL BEARING CAPACITY OF VERY SHALLOW FOOTINGS, LAWRENCE A LARKIN, ASCE PROCEEDINGS PAPER 6258, NOVEMBER, 1968

Hertzian stress-reducing means for gears

Abstract: Reduction in Hertzian and bending stresses in gears and in bearing assemblies is achieved by new configurations of gears and bearing assemblies employing combinations of materials in selected areas of the gears or bearing assemblies or cutting narrow slots into selected areas of the gear teeth or bearing assemblies. The increase in life of the gear or bearing assembly is expressed as L1 cH/H1n. For gears n 6.5 for bearings n 9. The Hertzian stress reduction provides in addition to increased operating life, higher reliability, higher load-carrying capacity and gears or bearings of quieter running characteristics at higher rotational rates than gears and bearings in the prior art.

Experimental Stability Studies of the Herringbone-Grooved Gas-Lubricated Journal Bearing

Abstract: Herringbone grooved gas lubricated journal bearing stability, testing effects of geometries and clearances on onset speed for half frequency whirl

Ultrasonic fatigue testing

Abstract: A method of duplicating the stress cycling experienced by a bearing race in which a probe is loaded radially into the raceway and ultrasonically vibrated in a tangential direction is disclosed.

Bearing having low-friction fibrous surface and method for making same

Abstract: This invention comprehends a bearing having a low friction surface formed of fibers of a low-friction resin, preferably polytetrafluorethylene, in a hard resin matrix, the longitudinal axes of substantially all of the fibers extending substantially parallel to the surface of the bearing.

Spring loaded bearing

Abstract: A plastic bearing constructed to support a shaft. The bearing has an irregular inner surface with spaced bearing points engaging the shaft. A spring is embedded in the plastic body of the bearing which exerts a force keeping the bearing surface in engagement with the shaft as the bearing wears.

Bearing foil anchoring arrangements

Abstract: A FOIL ANCHORING ARRANGEMENT FOR A FLUID FOIL BEARING IS DESCRIBED ESPECIALLY AS RELATED TO JOURNAL TYPE AND THRUST TYPE BEARINGS. THE ARRANGEMENT INCLUDES A PIN HAVING A RECTANGULAR CROSS SECTION AND A FOIL WHICH IS SPOT WELDED TO ONE SURFACE. A CHANNEL IN A STATIONARY ELEMENT OF THE BEARING IS PROVIDED TO RECEIVE THE PIN PARTIALLY WRAPPED BY THE FOIL AND MAINTAIN IT FROM ROTATING UNDER THE FORCES ENCOUNTERED BY THE FOIL DURING BEARING OPERATION.

Lubricating washers for reducing friction between moving parts in a cam follower

Abstract: An annular nylon washer is inserted between mutual surfaces formed by the integral end flange of the stud of a cam followertype bearing and the face of a counter bore in the axial end of the outer racering in which it is fitted. A similar washer is inserted between the mutual surfaces formed by the annular end plate and the face of the counterbore in which it is mounted. The ring is self-lubricating and acts to reduce the sliding friction between these surfaces to prolong the life of the bearing.

Method for detecting roller bit bearing failure

Abstract: A method for detecting failure of bearings in roller drill bits used in rotary drilling. Two drilling parameters-rotary torque and drilling rate-are measured and plotted with a third parameter ( psi ) equals ratio of the parameter of rotary torque divided by the parameter of drilling rate. A sharp increase in the third parameter psi indicates bearing failure.

Self-aligning clutch bearings with vibration damper

Abstract: The present invention is concerned with improved ball bearings for clutch mechanism, wherein the bearing races engaged by the balls are impressed in annular members consisting of rolled steel sheet to which a suitable contour is given, members being provided for incorporating the bearings in the clutch mechanism and possibly imparting a self-centering characteristic thereto, means being also provided for making said bearing selflubricating and noiseless in actual service.

Bearing sections for the covering with marble plates, panels and the like of walls both uninterrupted and interrupted by doors, windows and the like

Abstract: Bearing sections consisting of vertical sections, horizontal sections used when the building walls are not interrupted by frames, horizontal sections used when the building walls are interrupted by frames, and connecting sections. The bearing sections are of particular shapes and have teeth or appendices which allows the sections to be connected together as well as the building walls to be covered by, for example, marble plates in a dry manner.

Bearing vent construction and process of manufacturing the same

Abstract: A RAILWAY CAR BEARING VENT FORMED FROM A MOLDABLE ELASTOMERIC MATERIAL AND HAVING A MEMBRANE THROUGH WHICH A HOT KNIFE IS PASSED TO FORM SLITS THEREIN. THE HOT KNIFE OVERCURES THE MATERIAL IN CONTACT WITH IT SO THAT THE EDGES OF THE SLITS WILL NOT REBOND DURING OPERATION. THUS, PRESSURE CHANGES IN THE BEARING DURING AND AFTER OPERATION ARE RELIEVED WITHOUT ALLOWING THE ENTRY OF FOREIGN MATTER INTO THE BEARING OR WITHOUT INTERFERING WITH PROPER LUBRICATION OF THE BEARING ASSEMBLY.

Rolling cutter and seals therefor

Abstract: In cutters having a rolling cutter and a journal around which the cutter rolls there are bearing members In cutting rock and earth formations it is necessary to keep out the rock, earth, and extraneous material from the bearings This invention is directed to seals for sealing the bearings in their working cavity in the cutter so that dirt, rock, and extraneous material cannot reach the bearing and harm and damage the bearing surfaces

Self-aligning bearing

Abstract: A self-aligning bearing is constructed on the principle of a four-bar linkage. The bearing comprises a foundation, a bearing element, and a series of connecting struts which are flexibly joined to the foundation and bearing element.

Gas- or liguid-lubricated hydrostatic double-action thrust

Abstract: A gas- or liquid-lubricated hydrostatic double-action thrust bearing intended for taking axial loads in machines, for example, in centrifugal pumps. The bearing has a disc-shaped thrust plate with collars located at both sides thereof, the collars being mounted in the stationary body of the machine, which is also provided with passages for supplying power fluid into the face space, which, together with a collar, forms an annular chamber. The annular chamber through annular gaps communicates with a reduced pressure space and with a chamber located at the opposite face of the thrust plate, which, in turn, communicates with the reduced pressure chamber through a gap which is closer to the longitudinal axis of the thrust bearing than the said annular gaps.

Paper 9: Dynamic Hybrid Bearing Characteristics of Annular Controlled Leakage Seals

Abstract: The dynamic bearing characteristics of plain seals having appreciable length-to-diameter ratio are analysed by a perturbation method giving linear results. Non-linear effects have been treated in a more precise analysis, and a summary of the method and comparison of results with the simpler linear results is given. Some experimental results are given and compared with theoretical predictions. It is shown that length-to-diameter ratio has a considerable effect on seals of appreciable length, e.g. balance pistons, and that dynamic components of bearing action due to shaft rotation are comparable with the purely hydrostatic centring forces. Experimental results are shown to be reasonably in agreement with theory. It is concluded that the linearized bearing coefficients of seals given in this paper form a sufficiently sound basis for use in the vibrations analysis of pump rotors.

Pump for beverage dispenser

Abstract: A pump assembly for beverage dispensers having a pump chamber within which an impeller is disposed free of any shaft and bushing connections. A magnet embedded in the impeller cooperates with the driving magnet outside the chamber to align the impeller and support it on its bearing for rotation.

A General Analysis of Multi-Recess Hydrostatic Journal Bearings

Abstract: A number of assumptions enable the effects of both pressure and velocity induced flow between adjacent recesses to be included in an analysis of multi-recess hydrostatic journal bearings. Consideration of the rate of energy dissipation within a bearing enables an optimum speed variable to be defined which relates the speed of shaft rotation to the other describing parameters involved. The behaviour of a particular orifice compensated bearing of high aspect ratio was investigated at large values of eccentricity ratio and it was revealed that considerable interaction occurred between the recesses. The performance of the bearing was found to be determined jointly by its pressure ratio, speed variable and, significantly, the direction of loading. Considerable variations inload capacity occurred with changes in these parameters and it is shown that the range of operation of multi-recess bearings may be limited as some recess pressures may drop to the ambient pressure. The application of these results to practi...

Journal Bearings in Turbomachinery

Abstract: I - Theory and Practice.- 1 Bearing Development and Bearing Theory.- 2 Current Practice in Journal Bearings.- II - Performance in Steady Running.- 3 Functioning of Journal Bearings.- 4 Conventional Hydrodynamic Theory of Laminar Flow.- 5 Similarity Rules, Flow Regimes, and Characteristic Relations.- 6 Observed Bearing Performance.- 7 Approximate Assessment of Performance.- III - Dynamic Characteristics.- 8 Journal Bearings in Vibration.- 9 Conventional Theory of Linearized Dynamic Characteristics with Laminar Flow.- 10 Effects of Inertia of Oil on Dynamic Characteristics.- 11 Experimental Investigation of Dynamic Characteristics.- 12 Influence of Bearings in Turbomachinery Vibration.- IV - Operational Experience and Prospective Development.- 13 Operation of Journal Bearings in Turbomachinery.- 14 Prospects in Development of Journal Bearings.- Appendices.- i Analytical Solution for Very Narrow Bearing.- ii Analytical Solution for Infinitely Wide Bearing.- iii Transformation of Axes.- iv Limiting Value of Characteristics at High Eccentricity Ratio.- v Definitions and Units of Viscosity.- vi Properties of Turbine Lubricating Oils.- vii The Apparent Out-of-balance Coefficients.- References.

Experiment and Analysis of a Flat Disk Squeeze-Film Bearing Including Effects of Supported Mass Motion

Abstract: An experiment is described in which the motion of the supported mass was the main contributor to the generation of the squeeze film. An analysis was performed and a computer program written to predict the motion of the supported mass. Good agreement is shown between the analysis and the computer program and the experiment, except that two of the observed operation points cannot be verified.

Optimumly tuned and efficient viscous dampers

Abstract: A VIRBRATION DAMPER HAS MEANS FOR ATTACHING IT TO A STRUCTURE SUBJECT TO VIBRATIONS, I.E., A CRANKSHAFT, AND COMPRISING RELATIVELY MOVABLE MEMBERS ONE OF WHICH IS AN INERTIA MASS AND ONE OF WHICH DEFINES A HOUSING RELATIVE TO THE OTHER MEMBER TO RETAIN A VISCOUS DAMPING FLUID IN A SHEAR FILM COUPLING BETWEEN THE MEMBERS, ELASTOMERIC TUNING SPRING BEARING MEANS UNDER PRECOMPRESSION BETWEEN AND FRICTIONALLY ENGAGING WITH THE MEMBERS FUNCTIONING TO EFFECT TUNING AND DAMPING BY RESILIENT FLEXING SPRING ACTION FO THE BEARING MEANS IN ADDITION TO VISCOUS SHEAR DAMPING BY SAID VISCOUS FLUID AND TO ENABLE GUIDED STRESS RELIEF SAFETY RELATIVE SLIDING DISPLACEMENT OF THE MEMBERS ON THE BEARING MEANS, WHILE CONSTANTLY MAINTAINING THE SHEAR FILM SPACED RELATION BETWEEN THE MEMBER. EFFICIENT TUNING AND SHEAR DAMPING BY A VISCOELASTIC MATERIAL IS ENABLED.