Showing papers on "Bearing (mechanical) published in 1984"

Flow of a viscoelastic fluid over a stretching sheet

Abstract: This paper presents a study of the flow of an incompressible second-order fluid past a stretching sheet. The problem has a bearing on some polymer processing application such as the continuous extrusion of a polymer sheet from a die.

Advanced Dynamics of Rolling Elements

Abstract: 1 Introduction- 11 Rolling Bearing Elements and Basic Interactions- 12 Types of Analytical Models- 121 Quasi-Static Model- 122 Dynamic Model- 13 Nomenclature- 131 Coordinate Frames- 132 Vector Transformations- 133 List of Symbols- 14 Summary- 2 Equations of Motion and Coordinate Transformations- 21 Coordinate Frames and Transformations- 22 Equations of Motion- 221 Mass Center Motion- 222 Rotational Motion- 23 Moving Coordinate Frames- 24 General Motion Simulation- 25 Summary- 3 Geometric Interactions in Rolling Bearings- 31 Rolling Element/Race Interactions- 311 Ball/Race Interactions- 312 Roller/Race Interactions- 313 Roller/Race-Flange Interactions- 32 Rolling Element/Cage Interactions- 321 Geometric and Kinematic Considerations- 322 Hydrodynamic Models- 323 Dry Contact Models- 33 Race/Cage Interactions- 331 Geometric and Kinematic Considerations- 332 Hydrodynamic Models- 333 Dry Contact Models- 34 Interactions Between Rolling Elements- 341 Ball Bearings- 342 Roller Bearings- 35 External System Interactions and Constraints- 35l Equilibrium Constraint for Ball Bearings- 352 Equilibrium Constraint for Roller Bearings- 36 Summary- 4 Elastohydrodynamic Lubrication- 41 General Consideration in Lubricant Traction Modeling- 411 Rolling Element/Race Contact Zone- 412 Lubricant Rheology- 413 Typical Traction-Slip Behavior- 42 An E1astohydrodynamic Traction Model- 421 Film Thickness Computation- 422 Computation of Traction- 423 Estimation of Lubricant Constitutive Equation- 43 Traction Behavior of Some Lubricants- 431 US Specification MIL-L-23699- 432 US Specification MIL-L-7808- 433 Traction Fluid Santotrac 30- 434 Polyphenyl Ether- 435 SAE-30-Type Oil- 44 Summary- 5 Churning and Drag Losses- 5l Estimation of Drag Forces- 52 Estimation of Churning Moments- 521 Loss on the Cylindrical Surface- 522 Loss on the End Surface- 53 Effective Lubricant Viscosity and Density- 54 Summary- 6 Numerical Integration of the Equations of Motion- 61 Dimensional Organization- 62 Explicit Algorithms- 621 Step-Changing Criterion- 63 Implicit Algorithms- 631 Predictor Formula- 632 Corrector Formula- 633 Step-Changing Criterion- 634 Change of Order- 635 Computational Considerations- 64 Selection of a Method- 65 External Constraints- 651 Equilibrium Constraints- 652 Fictitious Damping- 66 Summary- 7 The Computer Program ADORE- 71 Program Overview- 72 Structure of ADORE- 73 ADORE Capabilities- 731 Bearing Types- 732 Types of Cages- 733 Operating Conditions- 734 External Constraints- 735 Radial Preloads- 736 Material Properties- 737 Lubricant Traction- 738 Churning and Drag- 739 Roller Skew- 7310 Rolling Element Skid- 7311 Cage Instability- 7312 Bearing Power Loss- 7313 Wear- 7314 Geometric Imperfections- 7315 Bearing Noise- 7316 Bearing Life for Arbitrary Load and Speed Cycles- 7317 Flexibility in Units- 7318 Graphic Output- 7319 Integrating Algorithms- 7320 Restart Capabilities- 74 Input/Output Data- 741 Input Data- 742 Print Output- 743 Plot Output- 744 User-Programmable Subroutines- 745 Data Management in ADORE- 75 Computer Resource Requirement- 76 Summary- 8 Some Dynamic Performance Simulations- 81 Numerical Considerations- 82 Vibrational Characteristics- 821 Cylindrical Roller Bearings- 822 Ball Bearings- 83 General Ball Motion and Skid- 84 Cage Stability- 85 Roller and Cage Motion in Cylindrical Roller Bearings- 851 Roller Misalignment and Skew- 852 Time-Varying Loads and Speeds- 86 Summary- 9 Experimental Validation of ADORE- 91 Ball Motion and Skid- 92 Cage Motion- 921 Cage Mass Center Orbit- 922 Whirl Velocities- 923 Coning Motion of Cage- 93 Summary- 10 Guidelines for Rolling Bearing Design- 101 System Overview- 102 Rotor-Bearing System Interaction- 103 ADORE: A Design and Performance Diagnosis Tool- 104 Summary- Appendix I: Hertz Point-Contact Solutions- Appendix II: Shrink Fit and Thermal Expansion of Races- Appendix III: Fatigue Life Computation- Appendix IV: Source Listing of ADORE- Appendix V: Typical Example- References- Author Index

The condition monitoring of rolling element bearings using vibration analysis

Abstract: A brief review on techniques of machine condition monitoring is presented followed by a description and results of a study involving the monitoring of vibration signatures of several rolling element bearings with a view to detecting incipient failure. The vibration data were analyzed and several parameters were assessed with regard to their effectiveness in the detection of bearing condition. It was found that all the parameters were of some value depending on the type of bearing failure encountered. Generally, frequency domain parameters were more consistent in the detection of damage than time domain parameters. However, sufficient evidence is produced to show that it would be unreliable to depend exclusively on any one technique to detect bearing damage.

Spherical kinematic joint

Abstract: An improved spherical kinematic joint which allows ease and convenience of assembly and disassembly, particularly assembly, by providing a plurality of substantially physically distinct bearing inserts in a sub-assembly such that the bearing inserts are effectively a unitary structure for the purpose of assembly and disassembly but which bearing segments expand easily with low manual force during assembly and disassembly of the various bearing insert embodiments from the head and/or cavity or spherical seat in another joint element or member, such as for example in the prosthetic joint embodiments, an acetabular cup. Further, such ease of assembly and disassembly can be accomplished while retaining great dislocation and separation resistance and can be accomplished in a manner which does not introduce significant axial play.

Roller-contact bearing with information sensor

Abstract: Roller-contact bearing with information sensor which comprises a fixed ring 1 and a rotating ring 2 having rolling paths for the rolling bodies 3 arranged in a cage 4 for retaining and angularly positioning the said rolling bodies 3, and in which the fixed ring 1 has a bearing surface 5 for mounting an information sensor device 10. The invention is characterised in that the information sensor device consists of a support plate 61 for a connection and contact assembly 12 which extends between the sensor 13 and its power supply 14.

Dynamic pressure type fluid bearing

Abstract: A dynamic pressure type fluid bearing comprises a housing provided with a cylindrical hole having a cylindrically shaped inner bearing surface for radial load and a bottom bearing surface for thrust load, and a shaft disposed in the cylindrical hole and having a cylindrically shaped outer bearing surface for radial load opposed to and cooperative with the inner bearing surface and an end bearing surface for thrust load opposed to and cooperative with the bottom bearing surface. At least one of the inner bearing surface and the outer bearing surface is provided with grooves for generating a dynamic pressure. A communication hole is provided in the bottom bearing surface and opens to the outside of the housing. The bottom bearing surface has around the communication hole an annular contact bearing surface which contacts the end bearing surface when the bearing is stationary.

Elastomeric supported hydrodynamic bearing

Abstract: A fluid bearing is disclosed which consists essentially of a number of bearing pads, each having a face member and a support member that are separated and bonded together by an elastomeric material. The face member will have a load engaging surface, and its back surface will have at least one arcuate portion to provide a point of inflection which opposes an identical arcuate surface providing another point of inflection located on the support member. In operation the pad which operates in a fluid that serves as a lubricant will develop friction and pressure forces, which move the pad in such a way as to provide a wedge for hydrodynamic lubrication.

Bearing system for reciprocating floor conveyor

Abstract: A floor member (10) of channel form is pushed downwardly to install it onto bearings (16, 90, 144) which have been previously installed onto guide tubes (12, 12', 12") which extend in the same direction as the floor members (10). The bearings (16, 90, 144) have sidewall portions which slope downwardly and outwardly to a lower edge (76, 108, 154, 156). These sidewalls (66, 68, 100, 102, 150, 152) are connected at their upper portions to the bearings (16, 90, 144) in such a way that they will flex inwardly, into spaces provided for them, in response to the downward "snap on" movement of the floor member (10). Brace wings (52, 54, 110, 112, 174, 176) may be provided to function together with the lower edges (76, 108, 154, 156) to hold the floor members (10) onto the bearings (16, 90, 144). Bearings (90, 144) are provided which themselves snap onto the guide beams (12', 12"). These bearings (90, 144) include lock flanges in the form of cantilever springs, resulting in a good tight fit despite size differences which may exist due to low manufacturing tolerances.

An Approximate Analysis of the Temperature Conditions in a Journal Bearing. Part I: Theory

Abstract: An analysis is presented for solving the energy equation for a journal bearing film, coupled with the heat conduction equation for the bearing sleeve. The analysis approximates the temperature profile across the film thickness by a fourth order polynomial while the circumferential temperature variation is expressed in terms of a Fourier series expansion. The solution gives the temperatures of the journal, the bearing sleeve, and the lubricant film from which the viscosity distribution can be obtained for use in solving Reynold’s equation. Because the method is quite economic in computer time it should prove useful in practical calculations of journal bearing performance.

Drive motor bearing apparatus

Abstract: A disk drive motor has a mounting plate with a circuit board on one face and a cylindrical hub extending therethrough. A stator is secured to the plate and exterior of the hub. A cup-shaped rotor overlies the stator and has a rotor shaft journaled in the hub by spaced sealed precision bearings. The bearing opening includes an integral ledge which forms bearing chambers having smooth, uninterrupted walls within which a bearing is secured. Each bearing has an outer race secured within the chamber and an aligned inner race secured to the shaft, with end sealing members to seal the bearings. Spring means are located between each ledge are the inner races of the corresponding bearings to load the bearings. In assembly, the one bearing is assemblied on the shaft and inserted into the hub with the outer race adhesively bonded in place. The opposite bearing is close fitted into the opposite bearing and the shaft is pressed into the bearing during the assembly. Each of said bearings is preloaded with about 20 to 30 percent of maximum and both lubricates the bearing and reduces operational bearing noise.

Sealing and bearing means by use of ferrofluid

Abstract: Sealing and bearing means by use of ferrofluid, in which a magnet is utilized effectively in cooperation with grooves engraved on one surface thereof, the grooves having the function for generating the dynamic pressure of the ferrofluid. The ferrofluid is retained in a gap between a rotary shaft and a magnet of cylindrical or disc type enclosing the rotary shaft concentrically. The magnet performs excellent two functions of bearing and sealing respectively.

Method of assembling a clutch release bearing and corresponding clutch release bearing, in particular for automotive vehicles

Abstract: In a clutch release bearing an axially acting annular spring bears on a maneuvering member and on a radial rim on a drive member, so as to urge the latter towards a flange on the maneuvering member. The annular spring is adapted to turn inside out during assembly of the clutch release bearing and due only to the drive member acting on it, changing from a first configuration in which it is generally concave to a second configuration in which it is generally convex.

High-Speed Floating-Ring Bearing Test and Analysis

Abstract: Testing of small high-speed floating-ring bearings, typical of those used in automotive turbochargers, revealed a discrepancy between ring speed measurements and ring speed prediction using isothermal bearing analysis. As bearing stability, energy loss, and load capacity are dependent on ring speed, an experimental program was undertaken to determine the effects of various bearing parameters on ring speed. The program results show that none of the 16 bearing parameters investigated increased the bearing ring speeds to those values predicted by the isothermal bearing analysis. In parallel with the experimental program, a thermal analysis was developed in which the effects of lubricant and bearing temperature on the ring speed of a floating-ring bearing way investigated. The ring speed predictions from this thermal floating-ring bearing model agree with the measured values except at the lowest and highest speeds tested. Therefore, for the type of floating-ring bearing design described in this paper, it is c...

Damping Seals for Turbomachinery

Abstract: Seals with rough surfaces proposed for stabilizing shaft motion and preventing leakage along shaft in machines such as turbopumps. Applicable to turbomachinery with speed limits raised and bearing life extended, avoiding costly shutdowns.

Precise bearing support ditherer with piezoelectric drive means

Abstract: A relatively solid mounting surface, which may be part of a leveling gimb supports a piezoelectric bearing mount which has the properties of an acoustic transducer. The transducer has electrodes thereon which are powered from multi-phase electrical sources causing the bearing mount, and a bearing jewel which is rigid therewith, to move so as to dither the jewel in a rotary or other preselected fashion, thereby reducing bearing friction. Bandwidth, level and phasing sequence of the power sources are adjustable permitting optimized average dynamic motion and corresponding increased readout accuracy.

Compliant hydrodynamic fluid journal bearing

Abstract: A novel air bearing structure prevents destructive bending moments within the top foil. Welds are eliminated by mounting the top bearing foil in the bearing cartridge sleeve without using a spacer block. Tabs or pins at the end of the top bearing foil are restrained by slots or stops formed in the cartridge sleeve. These structural members are free to move in a direction normal to the shaft while being restrained from movement in the direction of shaft rotation.

Method and apparatus to provide thermal isolation of process gas bearings

Abstract: Apparatus for cooling pliant film bearings of turbomachinery or the like and for protecting such bearings against heat transfer from the turbine side of the machinery. The turbomachine incorporates a hollow shaft for better cooling. Embodiments of the invention circulate cooling air through the interior of the hollow shaft and provide various structural configurations to thermally isolate the bearing shaft from the turbine wheel.

High-strain tests on lead-rubber bearings for earthquake loadings

Abstract: Dynamic tests on two lead-rubber bearings, 280 x 230 x 113 mm, are described in which a dynamic actuator was used to apply shear displacements of ±10 to ±140 mm at frequencies of 0.1 to 3 Hz, giving shear strains in the rubber of up to ±200%. The weight of the structure on the bearing was applied by a vertical jacking system and ranged from 35 to 455 kN. Sequences of cycles were performed to simulate earthquake conditions and force-displacement hysteresis loops were obtained. It was concluded that at strains approaching 200% in the rubber, the force-displacement hysteresis loop could be represented by the linear elastic slope of the rubber component plus a rectangle appropriate to the plastic shear of the lead, with some rounding of the corners of the hysteresis loop. There was a decrease in the area of the hysteresis loop of 20% after six cycles at 1 Hz with a maximum shear strain of 125% in the rubber; but recovery followed within minutes. In one bearing an attempt was made to locally confine the lead by screwing external plates to the first internal plate within the bearing at the top and the bottom, but no difference in performance between the two bearings was noted. The scope of the tests indicated that, with peak strains in excess of 100% in the rubber, the bearings would continue to perform satisfactorily for a sequence of very large earthquakes.

Supercharger rotor, shaft, and gear arrangement

Abstract: An improved supercharger (10) of the Roots-type. The supercharger includes a three-piece housing assembly (14, 16, 18) defining generally cylindrical chambers containing two rotors (20, 22) having meshed lobes (20c, 22c) of modified involute profile which pump air from an unshown inlet to an outlet (56). The rotors are fixed to stepped diameter shafts (24, 26) pressed into centrally located through bores in the rotors. Straight splines (24e, 26e) on the shafts form mating splines in the rotor bores to prevent rotation of the shafts in the bores. Bearing assembly (28, 30) disposed at adjacent ends (20a, 22a) of the rotors support one end of the rotors in the housing and fix the axial position of that end of rotors relative to the housing. Bearing assemblies (32, 34) at the outer adjacent ends (20b, 22b) of the rotors support the other end of the rotors in the housing. The bearing assemblies (32, 34) include inner races pressed on shaft bosses (24b, 26b) and outer races slidably disposed in wear-resistant sleeves pressed into bores in housing end section 18. The outer races of bearing assemblies (32, 34) are biased away from bearing assemblies (29, 30) to remove radial and axial bearing play in all of the bearing assemblies.

Pipe joint assembly with snap ring and associated method

Abstract: A pipe joint is restrained against axial separation by the use of a bearing ring. Various embodiments of bearing rings having wedging surfaces cause an increase in the resistance to pipe separation as the joint separating thrust increases. That is, as the force tending to cause pipe separation increases, the wedging surface on the bearing ring cooperates with a corresponding wedging surface on a spigot ring to increase the resistance of the pipe joint to separation. The spigot rings are connected to the spigots by welding, set screws, heat-shrinking, etc. A specially shaped snap ring or bearing ring and associated method of making the bearing ring is used to avoid possible problems resulting from manufacturing tolerances. Specifically, the bearing ring is constructed with a major diameter greater than diameters at other locations on the ring.

Seismic analysis of a rotor‐bearing system

Abstract: The seismic analysis of a rotor-bearing system is presented in the time domain. The governing equations of motion for the rotor are derived including the effects of rotatory inertia, shear deformation, gyroscopic effects, axial force, axial torque, stiffness and damping provided by the lubricants in the bearings, base translation and base rotation. A simple and efficient finite rotor element based on a Galerkin formulation is proposed to model the rotor. The effects of disks and flywheels mounted on the rotor are also included in the analysis. An example problem for a rotor-bearing system is solved using El Centro earthquake data. Four cases are investigated that will permit one to study the influence of spin, base rotation, comparison between rigid body model and beam model and the influence of axial force and axial torque. The results of the above study show that the gyroscopic effects amplify the response of the rotor-bearing system. The base rotations of the rotor-bearing system under seismic excitation contribute significantly to the response.

Wheel bearing unit with positively engaging connection of two annular parts which can be fitted one into the other

Abstract: So that no forces which have a negative effect on the bearing can be exerted during the manufacture of the axial fixing device as a result of plastic deformation, a circumferential restriction (7) is provided on the projection (6) which is to be deformed, the centre of which constriction (7) lies approximately in the region of the edge (5') of the bearing ring (5).

Correction method for vehicle-mounted geomagnetic field sensors

Abstract: A correction method for a geomagnetic field sensor (11) of a bearing indication system (10) mounted on a vehicle including a signal processor (13) for processing an output signal (Vx, Vy) of the sensor. The signal processor includes a storing function (15), comprising steps of storing the output signal of the sensor as data (6) of the bearing of the vehicle, while the vehicle is traveling, and computing a bearing correction vector (Xoff, Yoff) for correcting the output signal of the sensor on the basis of the stored bearing data. When the vehicle is judged to be subjected to a strong magnetic field, the bearing data stored may be all cleared. The bearing correction vector may be updated each time when a predetermined period of time is elapsed or the vehicle has traveled a predetermined distance.

Rotary anode X-ray tube having a sliding bearing

Abstract: The invention relates to a rotary anode X-ray tube having a sliding bearing and a further bearing system. The further bearing system, preferably a magnetic bearing, is constructed so that it can absorb substantially entirely the axial and radial bearing forces, while the sliding bearing, which is preferably constructed as a spiral groove bearing with liquid metal lubrication, is shaped so that it absorbs the bearing forces only for a small fraction. It therefore has only a low friction, but it permits the supply of the anode current and especially an effective cooling of the anode disk.