Showing papers on "Thrust bearing published in 2001"

Applied Tribology: Bearing Design and Lubrication

Abstract: Series Preface. Preface. Part I: General Considerations. 1 Tribology - Friction, Wear, and Lubrication. 2 Lubricants and Lubrication. 3 Surface Texture and Interactions. 4 Bearing Materials. Part II: Fluid-Film Bearings. 5 Fundamentals of Viscous Flow. 6 Reynolds Equation and Applications. 7 Thrust Bearings. 8 Journal Bearings. 9 Squeeze-Film Bearings. 10 Hydrostatic Bearings. 11 Gas Bearings. 12 Dry and Starved Bearings. Part III: Rolling Element Bearings. 13 Selecting Bearing Type and Size. 14 Principles and Operating Limits. 15 Friction, Wear and Lubrication. Part IV: Seals and Monitoring. 16 Seal Fundamentals. 17 Condition Monitoring and Failure Analysis. Appendix A Unit Conversion Factors. Appendix B Viscosity Conversions. Index.

Fluid bearing device

Abstract: A fluid bearing device achieves superior in wear resistance in starting and stopping and in manufacturing ability The fluid bearing device includes a shaft having a flange portion, a sleeve opposing to the shaft across a fluid bearing clearance of a radial fluid bearing, a counterpart member opposing to at least one of plane of the flange portion across a fluid bearing clearance of a thrust bearing The flange portion and the sleeve portion being formed of copper alloy of mutually difference composition

Groove Effects on Thrust Washer Lubrication

Abstract: A numerical model was developed to investigate the effects of groove geometry on the hydrodynamic lubrication mechanism of thrust washers. In order to achieve the objectives the isothermal, time-dependent, polar-coordinate Reynolds equation, including the cavitation and centrifugal effects, was solved numerically to determine the pressure distribution for various groove geometries and operating conditions. The polar coordinate Reynolds equation was discretized using the control volume finite difference approach. The results indicate that thrust washers are capable of supporting a significant amount of load with proper groove geometries. Design curves were generated for load support and other operating parameters as a function of each of the groove geometrical parameters (i.e., depth, width, number of grooves, and shape) as well as the operating conditions so that thrust washers performance can be predicted and optimized.

Load responsive hydrodynamic bearing

Abstract: A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies (6) each define at least one dynamic surface (22) and a plurality of support regions (B0). A plurality of flexing regions (37) are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions (B0). Each of the flexing regions (37) has a first beam-like element (38) being connected by an integral flexible hinge (44) with one of the support regions and a second beam-like element (39) having an integral flexible hinge connection with and adjacent support region (B0). At least one local weakening geometry of the flexing region (44) is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements (38, 39) and the local weakening geometry (44) become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

Magnetic thrust bearing with permanent bias flux

Abstract: A magnetic thrust bearing having a high speed rotation capability and low cost construction. The magnetic thrust bearing has permanent magnets to provide bias flux. The magnetic circuits of the control flux and bias fluxes are substantially non-coincident, which allows for a low reluctance and efficient path for the control flux. The flux paths of the permanent magnets are completely defined with minimized airgaps for achieving higher forces and efficiency and very low control currents produce extremely large forces. No radially magnetized permanent magnets are required and no permanent magnets are attached to the rotor.

Static and Dynamic Characteristics of Aerostatic Circular Porous Thrust Bearings (Effect of the Shape of the Air Supply Area)

Abstract: Recently, graphite porous material has been used successfully in an aerostatic bearing. In actual bearing design, it is often necessary to reduce the thickness of porous material to make the bearing smaller. However, a reduction in thickness results in a reduction in the strength of the porous material. In particular, when the diameter of porous material is large, it is difficult to supply the air through the full pad area of porous material because it deforms. Therefore, in this paper, two types of air supply method (the annular groove supply and the hole supply) in a circular aerostatic porous thrust bearing are proposed to avoid the deflection of the bearing surface. The static and dynamic characteristics of aerostatic porous bearing with these air supply methods are investigated theoretically and experimentally. In addition, the effects of a surface restricted layer on the characteristics are clarified.

Disk-drive motor rotating on a magnetically counterbalanced single hydrodynamic thrust bearing

Abstract: Reduced axial height, compact disk-drive motor rotating on a hydrodynamic radial bearing and a magnetically counterbalanced single hydrodynamic thrust bearing. The single hydrodynamic thrust bearing is configured between the underside of the rotor hub and the adjacent end face of a support cylinder in which the motor shaft rotates. To make the motor rotationally operable, instead of another hydrodynamic thrust bearing, the reduced axial-height configuration employs magnetic counterbalancing means associated with the cylindrical wall of the rotor hub. The magnetic counterbalancing means counterbalances thrust hydrodynamic lifting pressure generated in the single thrust-hydrodynamic pressure bearing and acting on the rotor hub when it spins.

A pin fin microheat sink for cooling macroscale conformal surfaces under the influence of thrust and frictional forces

Abstract: Conventional microheat sink design primarily focuses on the use of continuous fin arrays to optimally dissipate thermal energy from electronic components. By contrast, this paper experimentally measures the thermal and structural performance of two micro pin fin heat sinks designed for use in load bearing applications such as mechanical seals and thrust bearings. One pin fin array is of low porosity, which is more optimal for load bearing capacity, and the other is of high porosity, which is more optimal for heat dissipation. By using these two extreme cases, the thermal-structural tradeoff found in load bearing microheat sinks is demonstrated. The heat sinks are constructed of nickel, electrodeposited onto a stainless steel thrust ring using a modified LIGA technique. Under forced air cooling, the thermal performance of each is compared to a simple model based on a combination of macroscale pin fin heat sink results and classical correlations for fins in cross flow. The low porosity design is also tested under the application of a 44.5 N thrust load at 2500 rpm and found to be structurally sound. Experimental temperature profiles demonstrate a substantial benefit of the microheat sink in cooling the load bearing surface.

High thrust turbocharger rotor with ball bearings

Abstract: An improved turbocharger for railway locomotive sized engines includes, in a preferred embodiment, first and second axially spaced ball bearings supporting a rotor with the first bearing being a hybrid ceramic ball bearing mounted to accept both radial and axial loads acting on the shaft at the compressor end. The first bearing is mounted on a reduced diameter portion of the shaft, providing reduced bearing diameter to acceptably limit centrifugal loading of ceramic balls in the bearing against a surrounding bearing race. The first bearing has dual rows of ceramic ball bearings mounted to share all axial thrust loads on the shaft. The second bearing is also a ball bearing. Lubrication of the bearings is preferably by direct impingement on the inner race to minimize oil churning causing heating and power loss. Additional features and advantages are disclosed.

Anti-friction cam-operated friction disk clutch

Abstract: A vehicle steering column can be frictionally locked in selected positions of adjustment by a cam-operated friction disk clamping mechanism. The cam operator includes a rotary shaft having an anti-friction thrust bearing on one end and an anti-friction cam mechanism on the other end. Anti-friction elements in the bearing and cam mechanism enable the shaft to be easily operated, while permitting the friction disks to have a strong clamping action.

Bearing surface with improved wear resistance and method for making same

Abstract: A radial bearing and method for making the same are disclosed. Radial bearings are typically used in downhole motors to control the direction of drilling in directional drilling operations. The cuttings from the bit are carried away by the drilling fluid and flow across the surfaces of the bearings before being removed from the well. The cuttings will contain sand and other hard and/or corrosive substances that will erode the surfaces of the bearings and shorten their useful life. The bearing of this invention is provided with a wear resistant surface to inhibit such erosion. The bearing of this invention is made from a bearing blank to which is applied a first overlay of mild steel with dispersed cemented metal carbide pellets. The composition of the cemented metal carbide pellets is disclosed. The first overlay may be applied by any conventional technique. A second overlay of mild steel is applied to the first overlay utilizing a MIG welding process. As the second overlay is applied, a portion of the hard metal particles in the first overlay is dispersed in the weld puddle forming the second overlay. The result is a steel hybrid matrix that can be machined down to desired dimensions and which will provide improvements in wear resistance that enable the bearing to have an extended useful life even when used in highly erosive environments. This hardbanding process may be applied to any other metal part that is subjected to erosive environments such as thrust bearings, rotors, drive shafts and the like which would benefit from an improved wear resistant surface.

Self-aligning/centering rotating foil thrust bearing (air film type) utilized in a rotating compressor

Abstract: A rotating impeller disc of a rotating compressor is utilized as a thrust bearing (air film type) by clamping a compliant foil member on each side of the rotating impeller disc to cause the foil members to rotate with the impeller disc and relative to fixed bearing surfaces on each side of the rotating impeller disc. The fixed bearing surfaces and compressor housing sections enclose the impeller/foil assembly within a compression chamber. The rotating impeller/foil assembly drags along a layer of fluid on each side of the impeller/foil assembly and is caused to be centered within the compression chamber due to the equalized fluid film pressure build up on either side of the impeller/foil assembly with no external axially alignment device required. The impeller/foil assembly is integrated as a component of the motor shaft of the motor driving the compressor. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Combination magnetic radial and thrust bearing

Abstract: A magnetic bearing wherein axially spaced combinations of permanent magnets on a rotor and stator are polarized to levitate the rotor and positioned with the rotor magnets offset axially outwardly (or inwardly) of the stator magnets to allow a force balance to be achievable to bear axial thrust. An electrically energizable coil modulates magnetic flux between the respective stator and rotor magnets for each combination. A first electrical circuit regulates electrical energy to the coils for maintaining a reference position of the rotor. A second electrical circuit compares feed-back of electrical energy to at least one of the coils with a reference electrical energy of about zero amps or volts and integrates the differences until the difference is about zero to provide a signal to modify the reference position, whereby to attain a zero force balance position wherein the current which must be supplied to the coils may be reduced to near zero.

Hydrodynamic compliant foil thrust bearing

Abstract: One embodiment includes a plurality of equally spaced top foils (314) and corrugated springs (316) with one or more shims (318) underneath the trailing edge of each corrugated spring. The corrugated spring (316) forms an underspring for the top foil (314). Another embodiment incorporates at the trailing edge of the corrugated spring. The shim (318) under the trailing edge of the corrugated spring results in increased load capacity and stability and a decrease in lift- off speed of the rotating thrust disk (305). The shims (318) located at the outer radii of the corrugated springs result in increased bearing stiffness at the outer region of the compliant foil thrust bearing where the highest pressure occurs.

Steady State Performance Characteristics of a Tilting Pad Thrust Bearing

Abstract: The paper reports results of the experimental investigation into the steady state performance characteristics of a tilting pad thrust bearing typical of design in general use. Simultaneous measurements are taken of the pad and collar temperatures, the pressure distributions, oil film thickness, and power loss as a function of shaft speed, bearing load, and supplied oil temperature. The effect of operating conditions on bearing performance is discussed. A small radial temperature variation is observed in the collar. A reduction in minimum oil film thickness with load is approximately proportional to p -0.6 , where p is an average bearing pressure. It has also been found that the oil film pressure profiles change not only due to the average bearing load but also with an increase in shaft speed and temperature of the supplied oil.

Thrust dynamic pressure bearing

Abstract: It is an object of the invention to provide a thrust dynamic pressure bearing in which an unsymmetrical contact during rotation is prevented from occurring, and a dynamic pressure space is prevented from being clogged with abrasion powder generated by a contact at starting and stopping. In the thrust dynamic pressure bearing of the invention, a flange disposed on a shaft is tapered as moving form toward the outer circumference thereof, so that a dynamic pressure space between a thrust bearing face of a housing and a thrust receiving face of the shaft during rotation becomes wider toward the outer circumference thereof. Even if the shaft is tilted with respect the housing during rotation, therefore, it is possible to prevent an unsymmetrical contact of the thrust receiving face of the shaft in the vicinity of the circumference against the thrust bearing face of the housing, from occurring. In addition, the dynamic pressure space becomes wider as moving toward the outer circumference, so that the abrasion powder generated by the contact at starting and stopping can be easily discharged from a radially inward portion toward a radially outward portion of the dynamic pressure space.

Hydrodynamic oil-impregnated sintered bearing unit

Abstract: A hydrodynamic oil-impregnated sintered bearing unit 1 are comprised a hydrodynamic oil-impregnated sintered bearing 1 a, a housing 1 b, and a thrust bearing portion for thrust-supporting a shaft. A sealing washer 20 made of metal or resin material is arranged on an opening-portion side of the housing 1 b, and that, of a surface of the shaft 2, at least on a region including a portion opposite to the sealing washer 20 a thin layer 21 of a fluorine-containing polymer is formed.

Transmission devices, for ground vehicles and more particularly for motors-cars

Abstract: The epicyclic train is able to operate as a speed reducing gear when sun-wheel (5) is stuck by a one-way clutch (8), and in direct drive when clutch (10) is engaged. The whole coupling and control structure for the ratio change is essentially grouped on the sun-wheel element (5) which is slidingly movable and integral with an inverter control means (111) which engages brake (9) when disengaging clutch (10), and conversely. The brake (9) is mounted mechanically in parallel with a one way clutch (8), and allows speed reducing operation when the torque applied to the input shaft (31) is a retarding torque. The one-way clutch is mounted in parallel with an axially unslidable bearing (54) between a stator shaft (21) and a support (51) coupled for common rotation with and mutual slidability with respect to the sun-wheel element (5). For actuation of the control member (111) there is provide an hydraulic actuator (116), spring (114), and involvement of the helical teeth axial thrust (F1, F2). Useful for simplifying the control, keeping a possibility of other selective couplings, allowing other operating conditions, with the other rotary elements (6, 7) of the train, and avoiding the thrust bearings.

Study of the Tribological Behavior of a Thrust Washer Bearing

Abstract: This study addresses the mechanisms that distress a flat-faced thrust washer bearing system. This washer bearing system separates a helical gear and its carrier within a gearset. It was found that the bearing can experience distress by the combination of rotational speed, axial load, and the sequence and rate of their application. Distress is defined as a sudden rise in the real-time frictional torque and temperature. The various tests suggest the presence of hydrodynamic effects at certain rotational speeds and axial load combinations marked by decreases in the calculated effective coefficient of friction with decreases in velocity. In the tested cases, a distinct increase in the coefficient of friction occurs at the instant of distress. Presented at the 56th Annual Meeting Orlando, Florida May 20–24, 2001

Method of measuring preload in a multirow bearing assembly

Abstract: The preload in a double row production bearing assembly (A) is ascertained by comparing the deflection (Dp) produced in that bearing assembly by oppositely directed thrust forces (Fm(+),Fm(-)) with the deflection produced in a master bearing assembly (B) by equivalent thrust forces likewise applied in opposite directions. The master bearing assembly is similar in configuration and substantially equal in stiffness to the production bearing assembly, but exists in a state of end play. Each thrust force (F) is transferred through the rolling elements of one row and should be sufficient in magnitude to unseat the rolling elements of the other row. The preload in the production bearing assembly (S) equals the end play in the master bearing assembly (Em) plus the deflection in the production assembly (Dp) less the deflection in the master assembly (Dm). The endplay in the master bearing assembly is ascertained by extrapolating the deflection to zero thrust force.

Spring-Supported Thrust Bearings Used in Hydroelectric Generators: Comparison of Experimental Data with Numerical Predictions

Abstract: Laboratory experiments that simulate the conditions acting on large spring-supported thrust bearings in hydroelectric generators were performed and film thicknesses, temperatures and pressures were measured. A software package provided theoretical predictions of the experimental results. This software used a control volume, numerical formulation to model the three dimensional flow of mass, momentum and energy in the thrust bearing and included thermoelastic deflection of the pad and flow of oil in the groove between the pads. A detailed comparison of the experimental data with the numerical predictions showed quite good overall agreement, particularly with the deformed shape and temperatures of the pad. The agreement provided evidence of the fidelity of the software package and supported its continued use in analysis and design. Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in Toronto, Ontario, Canada, October 26–28, 1998

Disk drive unit with hydrodynamic fluid bearing unit and disk device with said drive unit

Abstract: A disk drive unit includes a rotary member, which has a spindle, and has an information-recording disk fixedly mounted thereon, and a bearing unit rotatably supporting the spindle. The bearing unit includes a radial bearing device, provided in opposed relation to an outer peripheral surface of the spindle, and a thrust bearing device provided in opposed relation to a distal end surface of the spindle. The radial bearing device has a concentric arc-shaped bearing surface, which is concentric with the circular outer periphery of the spindle, and a non-concentric arc-shaped bearing surface which is non-concentric with the circular outer periphery of the spindle. The disk drive unit further includes a motor for imparting a rotational force to the spindle, and a lubricating fluid filled in the bearing unit.

Compliant foil thrust bearing

Abstract: A compliant foil fluid thrust bearing has a single sided or two sided thrust disk (24) rotor, an integrally formed compliant foil member (40), and an underspring member (42). The non-rotating but compliant foils are located adjacent to the thrust face of faces or the rotatable disk and are formed as arcuate segments on washer-shaped disk members. The underspring member consists of three washer-shaped disk elements that together provide variable spring stiffness in both the circumferential and radial directions.

Turbocharger bearing system

Abstract: An enhanced bearing system for turbochargers incorporates a thrust collar centrally mounted on the rotating shaft interconnecting the turbine and compressor and a thrust bearing centrally located within the center housing to constrain the thrust collar. Central placement of the thrust collar allows journal bearings and journal seals to be placed immediately adjacent the turbine and compressor wheel attachment points on the shaft enhancing the shaft motion characteristics and sealing capability.

Thrust hydrodynamic bearing, spindle motor provided therewith, and disk drive utilizing the motor

Abstract: In a thrust dynamic-pressure bearing that through pump-in type spiral grooves generates dynamic pressure, a simple configuration to eliminate at the bearing exterior air bubbles liable to build up nearby the central portion of the bearing, yielding stabilized axial bearing force. The configuration lends superior endurance and reliability to the thrust bearing, and to a spindle motor furnished with the bearing. The configuration makes the circularly symmetrical dynamic pressure distribution, created by spiral grooves formed circularly symmetrical with respect to the bearing axial center, asymmetrical by the addition of an asymmetrical auxiliary groove(s). Air bubbles building up near the center of the spiral grooves are thus shifted to the area where the spiral grooves are formed. In the area where the spiral grooves are formed, the more inward the oil the higher the dynamic pressure. Therefore, because air bubbles will tend to shift from a region of high to a region of low oil pressure, the air bubbles get pushed out to the outer circumferential margin of the spiral grooves.

Adjustable preload shim for tapered bearings

Abstract: An assembly by which to effect incremental adjustments to the end play, or preloading, to a bearing set. Relatively rotatable first and second thrust rings have contiguously juxtaposed and interacting ramp surfaces. Interposed between the first and second thrust rings is an indexing spring that provides incremental adjustment of the first thrust ring with respect to the second thrust ring. A plurality of indexing pawls formed on the indexing spring interacts with a plurality of indexing teeth formed on one of the thrust rings. The second thrust ring is selectively rotatable with respect to the first thrust ring to effect axial translation of the first thrust ring by virtue of the interaction between said opposed, contiguously juxtaposed ramp surfaces. The indexing pawls preclude reverse relative rotation of the thrust plates.

High load capacity bi-directional tapered roller bearing

Abstract: The present invention is a bi-directional tapered roller bearing having a first cone rib ring thrust face “C” adjacent and facing the small diameter end faces of the roller elements, a second cone rib ring thrust face “B” adjacent and facing the large diameter end faces of the roller elements, and a cup rib ring thrust face “A” adjacent and facing the large diameter end faces of the roller elements. The bearing components are arranged such that, during primary thrust load operation, there is a gap between thrust face C and the small diameter end faces of the roller elements, a gap between thrust face A and the large diameter end faces of the roller elements, and contact between thrust face B and the large diameter end faces of the roller elements. With this arrangement, bearing roller element centrifugal loads act to reduce the contact forces between the roller elements and the bearing races.

Bearing for an adjustable rotor blade on a wind energy plant

Abstract: The invention relates to the bearing for an adjustable rotor blade on the rotor hub of a wind energy plant, with a roller bearing as the pivot bearing for the positioning drive, which can transfer high axial forces and large twisting moments with low relative movements between the bearing halves. One bearing half comprises a bearing ring with two positive-fit rows of roller bodies, radially offset from each other and the other bearing half comprises a bearing ring engaging with the above with a U-shaped section. The bearing ring for the rotor blade, forming the other bearing half, comprises two rings (10, 12) of varying diameter, which are independently fixed to the rotor blade (3). The circular root of the hollow rotor blade is split into two sub-shells (3a, 3b) and each sub-shell is fixed to one of the both rings (10, 12), of the one bearing ring.

Torsional shock absorber for a drill string

Abstract: A torsional shock absorber dampens rotary shock loading on a well drill string. An outer housing has drive splines on an inner surface. A mandrel is located within the outer housing and has drive splines on an outer surface that fit between the drive splines on the inner surface of the housing. Dampening bars are positioned longitudinally between the splines of the outer housing and the splines of the mandrel to absorb shock from non-uniform torsional loading at the drive interface between the outer housing and the mandrel. A balancing piston is located within the tool to compensate for pressure difference between drilling fluid pressure and lubricant contained within the shock absorber. A thrust bearing assembly is provided to accept axial thrust loads from the outer housing and transfers the load to the splined mandrel. A retainer transfers tensile loads from the housing to the mandrel through the thrust bearing.