Showing papers on "Bearing (mechanical) published in 1974"

Application of High-Frequency Resonance Techniques for Bearing Diagnostics in Helicopter Gearboxes

Abstract: : The feasibility of the High-Frequency Resonance Technique (HFRT) for defect analysis of rolling-element bearings found in a UH-1 helicopter main transmission was demonstrated. A study was conducted to determine optimum conditions under which to test each bearing. These included accelerometer location, speed, load, housing design and detection frequency. The results provided general testing criteria for each bearing. An analytical and experimental bearing race resonance study was conducted on each bearing. The bearings were then mounted in a test rig and run at various speeds, loads and housing designs. Good bearings and bearings with artificially-induced discrete defects were run.

Individual case for phonograph records

Abstract: A case for enclosing phonograph records and the like is disclosed which provides for rigid support of the record and protection from scratching, dust and moisture without allowing the surface of the case to contact the record's grooved surfaces thereby damaging those surfaces. The molded case is formed of a lid and a body hingedly joined at one edge of each. The lid and body are molded to form flush joints and a centering pin together with annular bearing zones. Together these insure the record stays in position within the case, is protected from crushing force external to the case and is further protected from moisture and scratching.

Virtually zero power linear magnetic bearing

Abstract: A linear magnetic bearing provides magnetic support by means of permanent magnets and control by means of electromagnets and an electronic control system such that virtually zero power is required to maintain the bearing in suspension. Persisting net force producing electric energization of the electromagnets resulting from displacement of the bearing causes the energization to be augmented to reposition the bearing to an oppositely displaced position of substantial equilibrium with minimized net force producing electric energization of the electromagnets. The linear magnetic bearing is effectively utilized in one application to significantly reduce the power requirements for magnetic levitation vehicles.

Analysis of Narrow Porous Journal Bearing Using Beavers-Joseph Criterion of Velocity Slip

Abstract: Analytical solution for performance characteristics of a narrow journal bearing is obtained. The analysis takes account of the velocity slip at the surface of a porous medium by using Beavers-Joseph criterion [1]. Results are presented for various bearing characteristics and compared with earlier results obtained by using no-slip condition. A comparison is also made with an earlier approximate analysis [8] which considers the slip effects but assumes the bearing wall thickness to be infinitesimally small.

A psychoanalytic reinterpretation of the effectiveness of systematic desenitization: experimental data bearing on the role of merging fantasies.

Abstract: Ten women with insect phobias were subjected to a variant of systematic desensitization in which a procedure aimed at stimulating a fantasy of "merging with mother" was substituted for muscle relaxation. The procedure, which had been used effectively in earlier experiments, consisted of the tachistoscopic subliminal exposure of the verbal stimulus MOMMY AND i ARE ONE during the visualization part of desensitization, whenever the subject's anxiety rose above a specified level. A control group of 10 other women with insect phobias underwent the same procedure except for them the subliminally exposed message was the neutral stimulus PEOPLE WALKING. On measures of both phobic behavior and anxiety, the experimental group manifested significantly more improvement than the controls. This was seen as lending support to the proposition that (part of) the effectiveness of systematic desensitization resides in its activating unconscious merging fantasies.

A Three-Dimensional Thermohydrodynamic Analysis of Sector Thrust Bearings

Abstract: Equations governing the steady-state thermohydrodynamic behavior of sector-shaped thrust bearings are solved numerically for an incompressible laminar flow of a Newtonian lubricant. The lubricant viscosity is taken as a function of the three-dimensional temperature distribution in the fluid film. Also, a general film thickness profile is allowed. Three dimensional heat transfer between the lubricant and both the moving and stationary solids is included in the analysis. The full thermohydrodynamic solutions are compared with other simpler solutions. It is shown that a type of adiabatic solution allowing for temperature gradients across the film can be used in most cases to predict accurately bearing load, friction, and lubricant flow. The results, expressed in nondimensional terms, can be applied to a wide range of operating conditions.

Reversible belt tensioning system

Abstract: A reversible belt tensioning system for releasably securing an endless belt to a roller mechanism. A pair of toggle actuation mechanisms longitudinally displace a pair of bearing block mechanisms. The bearing block mechanisms are connected to a roller which frictionally engages the endless belt during normal operation. Actuation of the toggle mechanisms which are fixedly mounted to a stationary frame member, longitudinally displace the bearing block mechanisms and roller mechanism to a forward position where the roller frictionally engages the endless belt. Release of the toggle mechanisms drives the roller to a rearward position in response to an associated movement of the bearing block mechanisms to release the belt from contact with the roller.

Concrete Bearing Strength—Support, Mix, Size Effect

Abstract: Although the problem of large forces acting over limited contact areas of concrete is often encountered in engineering design, a theoretical rendering of the behavior and ultimate bearing strength of concrete is extremely difficult because of the overall complexity of the problem. Experimental studies are, therefore, imperative. The bearing strength of concrete is affected by several diverse factors. In this paper, the nature of bed (rigid or yielding) supporting the specimen, supported area of specimen, concrete properties, and size of specimen are considered as the principal variables, and their effect on the bearing strength ratio, i.e., the ration of ultimate local bearing stress to the concrete cube strength is presented on the basis of comprehensive tests.

Scraper-chain conveyors

Abstract: A frame assembly for a scraper-chain conveyor which is usable as a drive or reversing station. The assembly has bearing units, which are supported by spaced-apart side walls. A shaft carrying a chain wheel for engagement with the scraper-chain assembly of the conveyor is mounted for rotation between the bearing units. The chain wheel is constructed from separate parts and can be readily attached to or detached from the shaft without removing the latter. The bearing units have hollow projecting parts which accommodate bearings for the shaft which are protected by seals. These projecting parts smoothly merge with the exterior of the chain wheel. The shaft has hollow end portions provided with splines which can be coupled to a journal introduced into the associated end portion from the exterior of the associated bearing unit which also provides access to the bearings and seals. This journal can then be coupled to a drive means to effect rotation of the shaft.

Lubricated radial bearing assembly

Abstract: Apparatus for supporting a rotor assembly of a gas turbine engine is disclosed. A lubricated ball type thrust bearing which supports one end of the rotor shaft is disposed within a bearing compartment formed between the rotor assembly and the engine stationary structure. One or more carbon seals, in operative relation to a seal plate on the rotor assembly, prevent the flow of excess ambient engine air into the compartment. Lubricating and cooling oil is supplied to the compartment where it is positively apportioned between the bearing and the seal plate.

Rotor blade retention system

Abstract: A rotor blade retention system connects an elongated rotor blade to a rotor hub that is rotatable about its central axis The connected rotor blade normally extends generally radially from the hub and is rotatable with the hub The retention system includes at least three laminated elastomeric bearings connected together in serial compression load transmitting relationship Each laminated bearing includes a plurality of alternating and bonded together layers of elastomeric material and substantially inextensible material The layers of each of the serially interconnected bearings are at least partially inclined relative to the longitudinal axis of the rotor blade In section taken radially of the longitudinal axis of the blade, at least a portion of each layer of each bearing projects longitudinally toward an end of the rotor blade Preferably, only one of the serially interconnected bearings is rigidly connected to the rotor blade The rotor blade is spaced radially, relative to its longitudinal axis, from at least all portions of the retention system other than the bearing to which the blade is rigidly connected

Separable bearing axle assembly and supported hub of a bicycle wheel or the like

Abstract: A hub of a bicycle wheel or the like rotatably mounted on an axle and bearing assembly. The assembly consists of an axle and bearings for supporting the specially formed hub which are separable but are ordinarily kept in assembled condition in the hub by a quick-release cam lock or clamp.

Vacuum pump having a rotor supported in the interior of its casing

Abstract: The present invention relates to magnetic support of the rotor structure in vacuum pumps, particularly turbomolecular pumps. This magnetic support eliminates the requirements for bearing lubricants, and the consequent degradation of the vacuum to be produced by lubricant vapors.

Axial thrust bearing

Abstract: The thrust bearing comprises an annular support within which at least one annular plate is retained. The plate defines either a planar slideway if the bearing is a smooth bearing or a planar raceway if the bearing is a rolling bearing. At least one axially deformable annular elastically yieldable member is retained in the support and applied against the plate.

Extraction method and apparatus

Abstract: A method and apparatus are provided for recovering oil from an oil bearing soil by means of an electrohydraulic shock wave generated in a liquid by capacitor electrical discharge means.

Pedestal wear plate

Abstract: In a railway truck, a wear plate is provided on the side frame between the downwardly facing surface of the pedestal opening and the bearing adaptor on the bearing and axle assembly. The wear plate is resiliently clipped onto the side frame, and stop means are provided to minimize movement of the wear plate relative to the side frame surface.

Lubricated bearing structure

Abstract: A bearing structure is provided for use in machinery wherein certain components thereof operate at high rotational speeds. The structure includes a shaft mounted for rotation within a stationary housing member. A pair of bearings, arranged in longitudinally spaced relation, is disposed between the shaft and the adjacent surface of the housing member. The housing member is provided with a passage for high pressure oil terminating at each bearing. Each bearing is of sleeve-like configuration and is provided with a plurality of radial holes which are in communication with the oil passage of the housing member. A plurality of longitudinal openings are formed in each bearing and interconnect the end faces of a bearing. The openings communicate with the holes of the bearing thereby permitting oil to flow to the end faces.

Method and means for balancing a gas turbine engine

Abstract: A method and means is provided for initially balancing a gas turbine engine and any replacement turbine therefor so that if the original turbine becomes damaged or inoperative, it may be readily removed and replaced without performing an additional balancing operation. The turbine is connected in overhung relation to the aft end of the engine rotor shaft so that it can be removed and replaced without disturbing a bearing or seal. Slight variations in the dimensions of different replacement turbines and rotor shafts which could potentially unbalance a rebuilt engine are accounted for during the initial balancing of the engine so as to make the turbine readily replaceable without subsequently rebalancing the engine.

Method for mounting a bearing in a universal joint

Abstract: Method for mounting a cylindrical bearing having a closed end wall around a trunnion of a cross member of a universal joint by fitting the bearing in a bore of the corresponding yoke under such conditions that the end wall of the bearing affords an elastically yieldable support, optionally through intermediate means, for the end face of the trunnion. The method comprises giving to the end face of the trunnion and to the parts conjugate therewith, namely the end wall of the bearing and/or the intermediate means, such an arrangement that, in a first stage of said fitting, when the parts conjugate with the end face merely come in contact with the latter and possibly in mutual contact, a first axial distance between the open end of the bearing and the end face is distinctly less than a second axial distance which must be finally obtained between the open end of the bearing and the end face. Thereafter, the end wall of the bearing and/or the intermediate means are plastically deformed, in a final stage of said fitting, so as to eliminate the differencebetween said two axial distances and thereby achieve said elastically yieldable support by elastic return consecutive to the plastic deformation.

Resilient truck axle bearing mounting

Abstract: A unitary resilient elastomeric pad is positioned between the bearing adapter and side frame of a railway truck. The truck side frame includes downwardly depending pedestal jaws spaced fore and aft of a bearing carried by the axle and defines longitudinally a semi-cylindrical load carrying surface between the jaws. Transversely, the load carrying surface is chevron shaped. A bearing adapter is carried by the bearing and defines a load receiving surface in opposed relation to the load carrying surface for matingly receiving same. The elastomeric pad is disposed in compression load carrying relation between the load carrying and load receiving surfaces and conforms to and bears against these surfaces.

Fatigue life of high-speed ball bearings with silicon nitride balls

Abstract: Hot-pressed silicon nitride was evaluated as a rolling-element bearing material. The five-ball fatigue tester was used to test 12.7-mm- diameter silicon nitride balls at maximum Hertz stresses ranging from 4.27 x 10 to the 9th power n/sq m to 6.21 x 10 to the 9th power n/sq m at a race temperature of 328K. The fatigue life of NC-132 hot-pressed silicon nitride was found to be equal to typical bearing steels and much greater than other ceramic or cermet materials at the same stress levels. A digital computer program was used to predict the fatigue life of 120-mm- bore angular-contact ball bearings containing either steel or silicon nitride balls. The analysis indicates that there is no improvement in the lives of bearings of the same geometry operating at DN values from 2 to 4 million where silicon nitride balls are used in place of steel balls.

Transient Response of Rotor-Bearing Systems

Abstract: The equations of motion necessary to calculate the transient response of a multimass flexible rotor supported by nonlinear, damped bearings are derived from energy principles. Rotor excitation may be the result of imbalance, internal friction, rotor acceleration, nonlinear forces due to any number of bearing or seal stations, and gyroscopic couples developed from skewed disk effects. The method of solution for transient response simulation is discussed in detail and is based on extensive evaluation of numerical methods available for transient analysis. Examples of the application of transient response for the analysis of rotor bearing systems are presented and compared to actual machine performance. Recommendations for the use and extension of the present system simulation model are discussed.

Rock bit bearing seal

Abstract: A bearing seal for a rock bit, including a non-elastic annular core member and inner and outer flexible sealing rings each securely bonded to the core member throughout substantially its entire circumference, the core member providing dimensional stability for the sealing rings and hence extending the useful life of the bearing seal despite the elevated temperature and pressure levels to which it is subjected.

Rack and pinion steering assembly

Abstract: A rack and pinion steering assembly for automobiles and the like dirigible wheel equipped vehicles having a longitudinally driven rack bar connected to wheel turning tie rod linkage by ball and socket joints with thin wall, tubular metal housings or casings which are easily and inexpensively attached to the ends of the rack bar by deformation and which preload the bearings of the joints to maintain a predetermined torque on the ball studs and eliminate end play between the tie rods and the rack bar. The bearings of the joints include a bearing cup between the ball end of the stud and the rack bar composed of a resilient plastic material and a bearing ring between the ball of the stud and the free end of the housing composed of a stiff nonyielding plastics material with the cup and the ring cooperating to envelope the ball end of the stud and the tubular housing compressing the cup radially and axially so that it will expand as wear develops, preventing looseness in the joint, while the stiff bearing ring provides a stable high-tensile, nonyielding load support for the ball stud.

Water lubricated bearing device

Abstract: Water lubricated bearing devices best adapted to be used in water or sea water are disclosed wherein a composite bearing member comprising an elastic bearing member lined with a thermoplastic resin compound is anchored to the inner wall of a bush fitted into a support member.

Gas-lubricated self-pressurizing radial bearing

Abstract: The bearing segments of the bearing are made with asymmetrical bearing surfaces of concave and convex shape. In addition, one or more flow ducts communicate the concave bearing surface with the convex bearing surface in each bearing segment so that during operation a part of the lubricating film between the shaft and bearing segment flows to a gap between the housing and bearing segment to float the bearing segment.