Showing papers on "Bearing (mechanical) published in 1986"

Polycrystalline diamond bearing system for a roller cone rock bit

Abstract: A roller cone rock bit is disclosed with an improved bearing system. The improvement comprises a main journal bearing which is substantially frustoconically shaped and a main roller cone bearing which is reverse shaped to mate with the journal bearing. The journal and roller cone bearings comprise polycrystalline diamond. The invention also includes a means for retaining the roller cone on the journal.

Theoretical Modeling of the Vapor Cavitation in Dynamically Loaded Journal Bearings

Abstract: A theoretical investigation is made of the evolution of a vapor-bubble for a submerged journal bearing under dynamically loaded conditions using the Elrod algorithm. This method conserves mass throughout the computational domain. A comparison study is performed to determine some of the consequences of applying a nonconservative theory (pseudo-Gumbel BC) to a dynamic problem. A complete dynamic cycle of a journal whirling in a circular path is chosen for the basis of comparison. Significant differences are observed in the load components near the end of the cycle. Further, good agreement with experiment is found for stationary and nonstationary cavitation.

Roll for use in calenders and the like

Abstract: A rotary pressure applying roll which defines with a parallel complementary roll a nip for a running web of paper, textile or other flexible sheet material in a calender or the like has a cylindrical shell surrounding a stationary carrier in the form of a rigid shaft A bearing element is installed between the shell and the carrier and several hydraulic pressure generating devices are mounted between the carrier and the bearing element to urge the latter against the internal surface of the shell The pressure generating devices are spaced apart from each other, as considered in the circumferential direction of the shell, and the cylinder chamber of each such device can receive pressurized hydraulic fluid at a different pressure The axis of a main pressure generating device is normally located in the common plane of the axes of the shell and of the complementary roll The other device or devices are installed at the one and/or the other side of such plane and can be operated to counteract forces acting substantially tangentially of the shell The carrier and the bearing element have cooperating spherical, flat and/or cylindrical guide faces which enable the bearing element to pivot about an axis that is parallel to the axis of the shell

Radial rolling bearing

Abstract: A roller bearing comprising an inner and outer raceway and a row of rollers arranged between and contacting the raceways, the axes of the rollers being substantially parallel to the axes of the raceways when the latter are coinciding, the rollers and the raceways having curved longitudinal section profiles in which the curve radii are substantially greater than the greatest distance between the central axis of the bearing and the surfaces of the raceways and wherein the rollers are axially movable between the raceways without being obstructed by axial limitations at the raceways or by limited axial cage play for permitting relative inclination and axial displaceability being limited only by the rollers being squeezed radially between the raceways.

Mixing Inlet Temperatures in Hydrodynamic Bearings

Abstract: Cold and hot lubricant mixing at the inlet to a hydrodynamic bearing has been an unresolved and critical problem in determining bearing performance. The paper offers a conceptual and experimental investigation of the mechanism of mixing in the groove, in terms of the relevant flows and temperatures. The carryover from pad to pad of the discharging hot fluid film, the flow dynamics in the groove and the effects of cavitation are all determined in detail in the light of available experiments. Results of an extensive series of tests aimed at measuring the mixing inlet temperatures as a function of a range of operating conditions and bearing sizes are correlated in terms of an appropriate mixing function. Empirical equations based on the above correlation for the determination of the inlet temperatures are then given for both thrust and journal bearings.

Performance Characteristics of Worn Journal Bearings in Both Laminar and Turbulent Regimes. Part I: Steady-State Characteristics

Abstract: The effects of geometric change due to wear on the dynamic characteristics of journal bearings are determined theoretically in both laminar and turbulent regimes. The dynamic characteristics such as spring and damping coefficients and whirl onset speed of a rigid rotor supported by two identical symmetrically aligned bearings are analyzed by a semianalytical finite element method, and the numerical results for various wear depth parameters are indicated in graphical form. The geometric change due to wear has significant effects on the principal spring coefficients and on the cross-coupled damping coefficients. The whirl onset speed for a worn journal bearing whose wear depth parameter is larger than 0.3 becomes higher than the speed for a nonworn bearing.

Calculation of the Dynamic Coefficients of a Journal Bearing, Using a Variational Approach

Abstract: The dynamic bearing coefficients are obtained from a solution to the variational equivalent of Reynolds equation. A perturbation method is applied to find the individual dynamic coefficients. The Finite Element Method is used in the numerical evaluation of the equations. The flow is assumed to be laminar, the lubricant is Newtonian. Allowance is made for viscosity-temperature dependency in circumferential and axial directions.

Bearing or roller bearing with data sensor

Abstract: Bearing or roller bearing with data sensor of the type having a stationary element carrying a magnetic field sensor device and a rotating element carrying at least one multipole magnetized ring placed coaxially with the rotating element and separated from the sensor device by a gap.

Acetabular cup assembly with selective bearing face orientation

Abstract: An acetabular cup assembly includes a metal shell component and a plastic bearing insert capable of assembly interoperatively, the metal shell component first being secured in position within an acetabulum and then the plastic bearing insert being receivable within the shell component, first at a preliminary axial position for ascertainment of the circumferential position of the bearing insert and the orientation of the bearing face of the bearing insert relative to the shell component and then at a fully-seated axial position wherein the bearing insert is permanently captured in the shell component, the bearing insert being readily withdrawn from the preliminary axial position for circumferential repositioning to attain appropriate orientation of the bearing face prior to capturing the bearing insert within the shell component.

Large diameter turbogenerator for generating electrical energy at high power

Abstract: A large diameter turbogenerator for generating electrical energy at high power, using a ring generator which is integrated on the circumference of the turbine wheel, is equipped (as an internal pole or external pole rotor) with highly energetic permanent magnets in the rotor and is incorporated in a load-bearing part. The stator and rotor of the ring generator are arranged in the load-bearing part and in the turbine wheel respectively and, according to the invention, each in addition has a plurality of bearing magnets. The bearing magnets which are arranged in the stator and the bearing magnets which are arranged in the rotor are designed in such a manner and are repelled from one another in such a manner that the propulsion forces are greater than the radial attraction forces between the stator and rotor, and in such a manner that a magnetic gap of constant width is maintained between the stator and rotor during operation.

Socket bearing assembly for a constrained ball and socket joint

Abstract: A socket bearing assembly for a constrained ball and socket joint is provided which comprises: (a) a plastic socket bearing having a wall and a spherically-shaped cavity which has an opening defined by a rim for receiving the ball, the opening being smaller than the ball, and the wall having at least two cuts therethrough which extend from the rim towards the equator of the spherically-shaped cavity and which divide the portion of the wall in the vicinity of the opening into at least two flexible segments which can move apart to allow the ball to enter the cavity; (b) a reinforcing band; and (c) means associated with the bearing for attaching the band to the bearing at a location where the band can prevent the flexible segments from moving apart, thereby constraining the ball in the bearing. The bearing assembly is easily assembled in the operating room making it simpler for surgeons to use constrained ball and socket joints in both original and replacement implantations.

Reflected signal bias in biotelemetry triangulation systems

Abstract: Accuracy of 4 3-tower triangulation systems was quantified using surveyed reference points. All reference points within line-of-sight (LOS) of towers produced accurate and precise bearings, but 52% of points non-line-of-sight (NLOS) to towers produced inaccurate and/or imprecise bearings due to reflected radio signals. These data were used to test performance of the Andrews, Huber, and Maximum Likelihood (ML) estimators of Lenth (1981). The Andrews estimator was more likely to fail to generate a location estimate than the Huber and ML estimators, but these latter estimators frequently generated incorrect estimates. Of those estimates generated, the Andrews estimator proved superior to the Huber and ML estimators by generating a larger proportion of confidence ellipses that included the actual radio location and by having a smaller mean distance between the estimated and true radio location. However, all 3 estimators performed poorly with confidence ellipse areas >0.6 ha. J. WILDL. MANAGE. 50(4):747-752 Accuracy of location estimates with biotelemetry triangulation is a function of the number and accuracy of receiving stations, and an animal's location relative to receiving stations (White 1985). The 1st and last factors are generally controllable by the investigator. Bearing accuracy, however, is not as easily controlled due to variables such as topography, vegetation, weather, and signal quality (Slade et al. 1965, Cederlund et al. 1979, Springer 1979, Hupp and Ratti 1983, Lee et al. 1985). A problem with telemetry system accuracy common to many studies is bearing error resulting from signal reflection (bounce) (Tester 1971, Hupp and Ratti 1983, Lee et al. 1985). Reflected signals cause inaccurate location estimates that should be identified and eliminated before data analysis. Although reflected signals may be easily detected when testing a receiving system, they are often impossible to identify when the transmitter location, and hence the true bearing, is unknown. Lee et al. (1985) suggested ways to identify reflected signals when 2 bearings are used for triangulation, but these methods are subjective and only identify bearings with large errors. Using only 2 bearings and the error polygon approach for triangulation in areas where signal reflection is a problem will result in inaccurate location estimates that cannot be identified and eliminated. Problems with signal reflection can be reduced by using -3 bearings for triangulation and by generating a location estimate with a technique that is robust to outliers caused by signal reflection. Lenth (1981) provided 3 techniques to estimate the source of a signal with multiple bearings: (1) Andrews, (2) Huber, and (3) ML estimators. The 1st 2 estimators were developed to be robust to outliers by weighting each bearing, thus providing an advantage over the error polygon approach when signal reflection is a problem. In addition, the estimators provide a rigorous estimation scheme for >3 bearings. Objectives of this study were to use techniques described by Lee et al. (1985) to quantify bearing accuracy of 4 3-tower triangulation systems and to use these data to test performance of the 3 location estimators presented by Lenth (1981) when a significant proportion of signals are reflected by topography. Financial support was provided by U.S. Dep. Energy Grants W-7405-ENG-36 to Los Alamos Natl. Lab. and DE-FGO02-85ER60297 to Colo. State Univ., Exxon Co., USA, and Colo. Fed. Aid in Wildl. Restor. Proj. 45-01-502-15050. We thank J. D. Depperschmidt, J. K. Garner, and J. C. Graham for field assistance, and appreciate the cooperation of D. M. Barker and other personnel of the Colony Shale Oil Proj. C. J. Amlaner, Jr., and J. T. Ratti critically reviewed the manuscript.

Noise reduction system

Abstract: A noise reduction system and method for reducing noise occurring during pauses in information bearing audio signals has an audio input connected to one input of a differential output circuit. A variable gain circuit has an input connected to the audio input and an output connected to the other input of the differential circuit. A dc control signal is derived from the incoming signals and controls the variable gain circuit to cause cancellation of a noise only signal during periods of no information bearing audio signals.

Optical deflector with a pneumatic and a magnetic bearing

Abstract: An optical deflector for deflecting a laser beam from a laser by rotating a polygon mirror uses a dynamic pressure pneumatic bearing as a radial bearing and a magnetic bearing as a thrust bearing. The deflector includes a hollow rotor rotatable integrally with the mirror, a stationary shaft received in said hollow rotor, a casing member accommodating the rotor and stationary shaft, and an annular rotor magnet assembly mounted on the outer periphery of the rotor. A first rotary magnet is mounted in an upper end portion of a rotary shaft and a first stationary magnet in an upper end portion of the stationary shaft in such a manner as to face each other with the same polarity, a repulsive force acting between the two magnets serving as a thrust magnetic bearing. A second stationary magnet is arranged to face the first rotary magnet with the same polarity. Further, a second rotary magnet is mounted in a lower end portion of the rotary shaft and a third stationary magnet in a lower end portion of the stationary shaft in such a manner as to face each other with the same polarity.

Belt tensioner with frustoconical pivot bearing

Abstract: A belt tensioner in which the bearing for mounting the pulley carrying pivoted structure on the fixed structure comprises a frustoconical sleeve bearing having a frustoconical exterior surface and a frustoconical interior surface engaged between annular portions of the two structures. The frustoconical surface of one of the annular portions is (1) formed on the exterior periphery thereof and (2) disposed in engagement with the interior bearing frustoconical surface. The one annular portion has a load center point disposed on the pivotal axis of the pivoted structure. The other annular portion has a load center point disposed on a line disposed within a plane passing through the pivotal axis of the pivoted structure and the rotational axis of the pulley corresponding to the one line of the two lines of intersection of the bearing frustoconical surface with the plane through which the radially inward force component transmitted by the pivoted structure is applied to the sleeve bearing. The load center points are positioned such that the radially inward force component transmitted by the pivoted structure and resisted by the fixed structure is transmitted generally from one load center point to the other along a line extending between the points which line is perpendicular to and bisects the one line so that the radially inward force component transmitted by the pivoted structure to the sleeve bearing is distributed evenly throughout the axial extent of the sleeve bearing.

Variable preload shaft bearing for turbocharger

Abstract: A rotating shaft of a turbocharger is supported by two rolling bearings enclosed in a bearing housing. Two collar members are interposed between the housing and bearings for supporting the bearings in the housing. A U-shaped preloading member is interposed between the two collar members in such a manner that the U-shaped member forms an oil chamber therein. The U-shaped member receives a pressure of a lubricating oil supplied to the oil chamber from an engine, and expands to puch the rolling bearings through the collar members with a greater force when the engine speed is high, and therefore, the oil pressure is high.

Cooling networks for pcd bearing surfaces

Abstract: Polycrystalline diamond wear surfaces (17) in bearing structures (11) are maintained at temperatures that prevent thermal degradation in spite of exceptionally high loads. This temperature control is accomplished by segmenting the diamond wear surface to provide interrupt channels (13, 15) through which the energy build-up at the diamond wear surface is maintained below the thermal degradation level. Cooling fluid may be caused to flow through the interrupt channels, the higher the velocity of fluid flow around the diamond bearing surface, the greater the cooling effect.

Alignment compensator for linear bearings

Abstract: An alignment compensator (19) for use with a linear bearing (13a) which is mounted on a first support member (3a) which is aligned substantially parallel with a second support member (3b). The support members (3a, 3b) support a movable carriage (11). The compensator includes a body member (19) formed of an elastically deformable material and includes angular deflection means (33) for compensating for misalignment between the support members (3a, 3b) via angular elastic deformation of the body member (19).

Ferrofluid bearing and seal apparatus

Abstract: A composite ferrofluid bearing and seal apparatus which comprises a ferrofluid seal apparatus which contains disposed therein a bearing element, to form a ferrofluid-film bearing with the surface of a shaft, the ferrofluid seal apparatus retaining the bearing ferrofluid film within the bearing cavity, by forming a ferrofluid O-ring seal, held by magnetic flux, at each end of the bearing element, the composite ferrofluid bearing and seal apparatus acting to contain the bearing ferrofluid film within the fluid-film bearing cavity and to exclude gases from being entrained in the ferrofluid.

Bearing structure and a floating vessel comprising such structure

Abstract: A bearing structure which may, for example, be used for rotatable mounting of a turret or a rig (11) on the hull (14) of a vessel comprises a first annular bearing surface which is supported by the vessel hull (14), and which may be substantially plane or cylindrical. A second annular bearing surface which is in engagement with and supported by the first bearing surface is formed on the turret or rig (11). The hull (14) of the vessel is exposed to heavy forces caused by wind and waves, and such forces may cause deformations of the hull and consequently of said first bearing surface. In order to compensate for such deformations, the first bearing surface is divided into sections, and position control means, such as mechanical, pneumatic, or hydraulic spring means, are provided for maintaining all of the bearing surface sections in abutting engagement with said second bearing surface formed on the turret or rig (11). The said hydraulic spring means may be in the form of hydraulic cylinders or jacks to which hydraulic fluid is supplied at a pressure which is increased when the distance between the respective bearing surface section and the supporting part of the hull is decreased due to deformation of the hull, and vice versa.

Shaft alignment method and apparatus

Abstract: A cylindrical alignment housing is fixed to a housing of one of two axially aligned items of equipment. A cylindrical bearing housing is concentrically positioned around the cylindrical alignment housing, such that the cylindrical bearing housing is rotatably supported at a given position on the cylindrical alignment housing, which is fixed to the housing of the aforesaid one item of equipment. A mechanical coupling is provided between the bearing housing and the shaft of the other of the two equipment items that the bearing housing and the shaft will rotate in concert. A laser is positioned on the rotatable bearing housing and a prism is positioned on the other of the two items of equipment. The cylindrical bearing housing and the shaft of the aforesaid other equipment item are rotated together in concert, and measurements are taken using the laser and prism to determine whether the shafts are properly aligned with each other.

Compression Behavior of Concrete Masonry Prisms

Abstract: An analytical investigation using a three‐dimensional finite element model was conducted to study the complex behavior of hollow block prisms under axial compression. Detailed stress distributions in different directions were determined which help in understanding the composite behavior and failure mechanism of both face shell and fully‐bedded mortared prisms. The effects of type of mortar bedding, mortar deformational characteristics, block size, heightto‐thickness ratio, number of mortar joints, and stiffness of bearing plates on the behavior of axially loaded prisms were studied. The results show that the most significant parameters are the type of mortar bedding, the prism geometry, and the stiffness of bearing plates. Recommendations for the determination of masonry compressive strength and evaluations of code provisions for the testing of concrete masonry prisms are presented.

Composites for Aerospace Dry Bearing Applications

Abstract: Most bearings associated with flight-control applications in fixed wing aircraft and helicopters comprise polymer-based composites in the form of thin layers, ~0.3 mm thick, adhesively bonded to a metal substrate. The various types of composite used for this purpose are described and information given on how their friction and wear properties depend on the conditions of sliding; stress, temperature, counterface metal, contamination by fluids, type of loading, and various kinematic factors associated with the bearing design. A long-standing objective has been to relate friction and wear performance to composite structures and compositions and some results are given from recent research describing progress towards this end. Finally, brief mention is made of future trends and requirements for composites in dry-bearings, with particular reference to high temperature applications.

Hydraulically damping bearing

Abstract: A hydraulically damping bearing which includes an inner bushing arranged in an outer bushing and an elastic element inserted therebetween. Chambers are provided within the elastic element which are filled with a damping medium and are connected with each other hydraulically by way of throttling channels extending in the area of the outer bushing. The throttling channels terminate in the chambers which, like the throttling channels, are sealed off against the outside. The bearing consists of two bearing halves adapted to be axially inserted into one another which include elastic bellows halves connected with the outer and inner bushing. The bellows halves include mutually opposite annular beads projecting into the interior of the chamber, between which is arranged an enclosed overflow channel.