Showing papers on "Bearing (mechanical) published in 1990"

Method and apparatus for analyzing rotating machines

Abstract: A vibration transducer (22) is mounted to a rotating machine (20) for sensing vibration thereof. An output electrical signal from the vibration transducer is analyzed to generate a level display (18) of vibrational displacement per unit time, a speed display (22) indicative of rotational speed, and a bearing condition display (20) indicative of bearing condition, all displays derived directly from the vibration transducer signal. The electrical signal is transformed (36) into a frequency spectrum that has an amplitude for each of a plurality of narrow frequency ranges or bins. Each frequency bin has a characteristic center frequency and a predefined width or band of frequencies. A speed analysis program (38) identifies a set of at least first, second and third order related frequency bins, i.e. frequency bins whose center frequencies are an even multiple of each other, that have a significantly high amplitude and provides the lowest bin center frequency as a control signal to the speed display. A bearing condition analysis program (40) eliminates the bins that are integer multiples of the running speed and lower frequency, e.g. less than third order, identifies sets of bins with relatively large amplitudes that are integer multiples of each other, and selects the set of bins with the largest amplitude as being controlling of bearing condition. After elimination of frequencies not indicative of bearing condition, the bearing defect frequency remains. The amplitude of this frequency is displayed on bearing condition readout (22). The amplitude indicating the severity of the bearing defect.

A planar air levitated electrostatic actuator system

Abstract: The design and testing of a micromotor capable of moving multiple objects in three dimensions is discussed. The fixed surface of the motor, fabricated on a silicon wafer, contains air nozzles that levitate rigid platforms and conductive plates that generate an electric field to apply forces to platforms. Initial testing shows that the air nozzles form a stable very low friction bearing, and the motor is capable of several hundred microns of motion in two dimensions with fields generated by a 2 volt potential. Applications of this motor include a microrobotic work cell. Testing was limited to verification of the fundamental principles of operation, but experimental results indicate that a two-dimensional linear electrostatic stepper motor should be realizable with this process. In addition, it should be possible to control the vertical motion of the platforms by varying either the supply voltage or bearing pressure. >

An Efficient, Robust, and Time Accurate Numerical Scheme Applied to a Cavitation Algorithm

Abstract: In this paper, an implicit numerical scheme, based on an approximate factorization technique, is applied to a cavitation algorithm. The algorithm is a modified version of the Elrod cavitation algorithm, which automatically predicts film rupture and reformation in bearings. At each time step, Newton iterations are performed to achieve time accurate solutions for unsteady problems. This numerical scheme is applied in both orthogonal and nonorthogonal grid arrangements. An aligned finite grooved bearing and a flared, misaligned line grooved bearing are analyzed using this new approach. The predictions are compared with the results obtained with procedures currently being used. The new scheme is robust, quickly convergent, and provides time accurate solutions with a minimum expenditure of CPU time.

Copier with retractable charging unit to prevent damage to drum when removing process cartridge

Abstract: An image forming apparatus includes a cartridge detachably mountable to the image forming apparatus, the cartridge including a movable image bearing member; a charging member having a contact member for contacting to the image bearing member in the cartridge to charge the image bearing member, the contact member is mounted in the image bearing member; a supporting member for supporting the contact member for movement between a first position where the contact member is contacted to the image bearing member and a second position where the contact member is away from the image bearing member; a member actable on the supporting member in accordance with mounting or dismounting of the cartridge relative to the image forming apparatus; wherein upon dismounting of the cartridge, the contact member is moved from the first position to the second position.

On the bearing strength of bolted graphite/epoxy laminates

Abstract: One of the basic failure modes of bolted composite laminates is bearing fail ure. This mode of failure occurs in the material immediately adjacent to the contact points of bolt and laminate, and is caused primarily by compressive stresses acting on the hole boundary. The results of an experimental program which measured the bearing strengths of two different types of graphite/epoxy specimens are presented. The influence on the bearing strength of several important parameters including lateral constraint and ply orien tation are shown. Strains were measured in the vicinity of the loaded hole to quantify the extent of bearing failure. A new approach to predicting bearing failure is outlined. The Delamination Buckling Model (DBM) assumes that ply buckling following delaminations is a major feature of bearing failure. Quantitatively good agreement was found between ex periment and model results.

Notary drill bits

Abstract: A rotary drill bit comprises a bit body having a shank for connection to a drill string and a passage for supplying drilling fluid to the face of the bit, which carries a plurality of polycrystalline diamond preform cutting elements. The cutting elements on one side of a diameter of the bit have positive side rake and the cutting elements on the other side of the diameter have negative side rake so that the vectorial sum of the reaction forces between the formation being drilled and the cutting elements provides a resultant lateral imbalance force acting on the bit body as it rotates in use. The gauge of the bit body includes low friction bearing pads so located as to transmit the resultant lateral force to the sides of the borehole. Since the bearing pads are of low friction, they slide around the surface of the formation and any tendency for bit whirl to be initiated is reduced. The lateral imbalance force may also be provided by varying the back rake of the cutting elements on different parts of the bit, or by including an asymmetrical mass of material in the bit body.

Turbocharger bearing retention and lubrication system

Abstract: A turbocharger includes a rotating shaft which is supported within the turbocharger center housing (14) by rotational bearing elements. The bearing cartridge is located axially within the housing (14) by a pin (72) which extends through orifices drilled in the center housing (14) and in the bearing outer ring (52). The pin is relatively smooth, so that excursions of the bearing cartridge assembly (24) with the shaft (26) is permitted when the shaft is accelerated through critical rotational speeds. These excursions are damped by lubricating fluid communicated into grooves circumscribing the bearing outer ring (52) through lubrication passages (82, 84) extending through the pin. The lubricating fluid in the grooves communicates into the intersticial space defined between the outer ring (52) of the bearing cartridge assembly and the center housing (14) to thereby dampen the excursions of the bearing cartridge assembly (24).

Process cartridge detachably mountable to image forming apparatus

Abstract: A process cartridge detachably mountable to an image forming apparatus includes an image bearing member; a developing device having a developer carrying member; a supporting device for supporting the image bearing member and the developer carrying member; a first device actable on the image bearing member; a second device actable on the developer carrying member; wherein the image bearing member and the developer carrying member are urged toward each other by the first and second devices.

Compound shape rotating bearing

Abstract: A prosthetic joint includes a first bearing element which is attached to a first bone and has a substantially flat bearing surface. A second element having a bearing surface is attached to a second bone. A bearing is disposed between the first and second elements. The bearing has a central axis and is defined by a first surface and a second surface. The first surface is substantially flat and is at least partially in contact with the first flat surface of the first element. At least a portion of the second surface is in contact with the surface of the second element. The area of the planform of the first surface of the bearing is smaller than, and dissimilar in shape from, the area of the planform defined by the second surface of the bearing.

Natural gamma-ray spectrometry in hydrocarbon-bearing sandstones from the Norwegian Continental Shelf

Abstract: Abstract Concentrations of thorium (Th), uranium (U) and potassium (K) are measured using natural gamma-ray spectrometry (NGS) logs. The precision of NGS measurements in sandstones varies: K measurement is in general moderately good; Th measurement varies with the service company involved; U measurement is unreliable. Concentrations of Th, U and K in standard tables of minerals used commonly in log evaluation are not representative of the actual elemental concentrations found in sandstone minerals. Th/K cross-plots are shown to be unsuitable for the identification of clay minerals in sandstones. Illite cement cannot under normal geological circumstances be identified from the K content of the rock. Authigenic kaolinite has no particular affinity for concentration of Th. Th in sandstones is concentrated predominantly in detrital heavy minerals with up to 200f the total Th present in silt-sized and finer authigenic REE-phosphates and Th salts. Variation in the K content of micas from some Jurassic sandstones demonstrates the need for using formation-specific chemical data for the minerals of interest (micas, feldspars, clay minerals) as input parameters in normative calculations. Appropriate statistical control of the validity of Th, U and K contents for specific minerals is required.

Process cartridge detachably mountable to image forming apparatus featuring a peripherally supported image bearing drum

Abstract: A process cartridge detachably mountable to an image forming apparatus includes an image bearing drum; process device actable on the image bearing drum; a housing for accommodating the image bearing drum and the process device; and supporting means for rotatably supporting the image bearing drum at an outer periphery of the image bearing drum.

Dynamic pressure bearing device

Abstract: A dynamic pressure bearing device includes a sleeve and a shaft member which is rotatably fitted into the sleeve. The sleeve is made of an aluminum alloy containing a carbon fiber and has a radial bearing surface formed in an inner peripheral surface and a thrust bearing surface formed in a lower end surface. The shaft member includes a base portion having a thrust receiving surface formed on an upper surface, and a shaft portion extending upright from the base portion and having a radial receiving surface formed on an outer peripheral surface. A first dynamic pressure generating groove is formed in at least one of the radial bearing surface and the radial receiving surface, and a second dynamic pressure generating groove is formed in at least one of the thrust bearing surface and the thrust receiving surface. The shaft member including the shaft portion and the base portion is molded from a synthetic resin as a unitary body. The thrust bearing surface is tapered so that a thrust bearing gap formed between the thrust bearing surface and the thrust receiving surface increases gradually, radially and outwardly.

Oil-impregnated sintered bearing

Abstract: PROBLEM TO BE SOLVED: To sufficiently store lubricating oil with a simple and compact configuration, and to excellently feed the stored lubricating oil to a bearing part side SOLUTION: Lubricating oil storage parts 13d and 13e are demarcated on both sides across a fixed part 13a by making use of an outer circumferential side of a bearing member 13 having a large circumferential length to store lubricating oil of sufficient quantity, and the lubricating oil stored in the lubricating oil storage parts 13d and 13e on the outer circumferential side of the bearing member 13 is sucked by an inner side of the bearing member 13 having the capillary force larger than that of the lubricating oil storage parts 13d and 13e, and fed to the bearing part side

Light weight flexible coaxial vapor recovery hose

Abstract: A coaxial vapor recovery hose assembly comprising an inner hose, an outer hose, and structure for holding said hoses in concentric relationship; wherein the inner hose is substantially reinforced to be relatively incompressible as well as being capable of bearing tensile stress applied to the assembly and having an outside diameter; wherein the outer hose is corrugated and has an inside diameter larger than the outside diameter to define a vapor passageway therebetween.

Bearing cooling arrangement for air cycle machine

Abstract: In air cycle machines with hydrodynamic bearings, the mass flow rate of coolant (36) passing through a series of bearings (32, 28, 30) is metered before the coolant passes through the final bearing (30). The final bearing operates at an internal pressure equivalent to that present in the region (72) into which coolant exhausts after exiting the final bearing. Since coolant in the final bearing is at the same pressure as air immediately downstream from the bearing, no rotating seal is required at the outlet of the bearing cooling flowpath.

Rolling bearing with a sensor unit

Abstract: A rolling bearing has a sensor unit disposed on one of the opposite circumferential surfaces of a fixed ring of the bearing. The sensor unit includes two strain gauges disposed on the circumferential surface of the fixed ring, one strain gauge extending in the circumferential direction fo the fixed ring and the other strain gauge extending in the axial direction of the fixed ring. Preferably the strain gauges are arranged to overlap with each other and to cross at right angles or obliquely to each other. A plurality of performance characteristics of the bearing are detected on the basis of output signals from the two strain gauges. The detection of the performance characteristics enables the rolling bearing to be monitored during operation with respect to applied load, the rotational speed and acceleration of a rolling ring thereof, a rise in temperature thereof and an abnormal vibration thereof.

Analysis of a Finite Grooved Misaligned Journal Bearing Considering Cavitation and Starvation Effects

Abstract: The effect of journal misalignment on the predicted performance of a finite grooved journal bearing is analyzed in this paper. The numerical procedure used incorporates a cavitation algorithm, which automatically predicts film rupture and reformation in the bearings. The misalignment considered varies in magnitude and direction with reference to the boundaries of the bearing. In addition to the misalignment, the effect of lubricant starvation at the groove is also considered and compared with flooded inlet conditions. The effects of various degrees of starvation, or higher lubricant supply pressure, bearing length to diameter ratio and groove size are also investigated

Encapsulated motor with precision bearing registration

Abstract: The rotor of an electrical motor, such as a hybrid permanent magnet stepping motor or a variable reluctance motor is assembled on a rotor shaft, and includes at least one lamination stack and a pair of supporting bearings, with the outer diameter of the bearings being slightly larger than that of the lamination stack. A stator is assembled from a stator lamination stack including a pole configuration and a pair of unmachined end caps registered and secured to the lamination stack such as by thru bolts. The registered stator assembly is potted to unitize the assembly, fixing the relationship between the end caps and the lamination stack, and providing a smooth continuous bore through the center of the stator assembly. The thus potted assembly is machined as by diamond lapping to form a continuous bore accurately machined through the center of the stator, concurrently forming bearing surfaces in the end caps and an intermediate machined section in the lamination stack. The rotor assembly is inserted into the stator assembly, with the machined bore providing bearing mounting surfaces in the end caps and an air gap for rotation of the rotor in the lamination stack.

Demodulating High Frequency Resonance Signals for Bearing Fault Detection

Abstract: The high frequency resonance technique is an established means both of detecting early failure and of monitoring damage growth to roll element bearings. Applying the technique normally involves selecting a narrow band signal (often centred on a structural resonance) and recovering its demodulated envelope (to identify frequencies characteristic of damage to particular elements). This was formerly performed by analogue circuitry, whose parameters are not readily changed. If digital demodulation attempted to replicate the analogue process stage by stage, the computational effort would be so great as to render it impracticable. The theoretical basis of these procedures is outlined and examples of application to vibration data from bearing test rigs are given. Characteristic repetition frequencies can be identified in spectra of the demodulated envelopes and faulty elements identified.

Analysis of Crankshaft Bearings Using a Mass Conserving Algorithm

Abstract: A mass conserving algorithm (Elrod algorithm) which uses the Jakobsson, Floberg, and Olsson cavitation boundary conditions has been implemented to analyze crankshaft bearings. The main and connecting rod bearings of a typical automotive engine are considered. Some sample steady-state results are presented. The inverse problem (given the load, find the journal orbit) is solved for real engine loads. Comparisons are made with a non-conservative algorithm based on the Reynolds boundary condition. Significant differences in the cavitation zones and oil flows are observed between the two algorithms. In all cases, the oil flow into the bearing is found to match the oil flow out of the bearing for the Elrod algorithm. Presented at the 44th Annual Meeting in Atlanta, Georgia May 1–4, 1989

Angle adjusting device for a display device

Abstract: An angle adjusting device, of which assembling work is performed in narrow space, wherein a rotatable axis previously provided with frictional components thereon is inserted paralelly into a bearing hole provided on a bearing by passing an annular groove provided on the rotatable axis through a vertical slit provided on an edge portion of the bearing, and is inserted horizontally into another bearing hole provided on another edge portion of the bearing

Integral motor propulsor unit for water vehicles

Abstract: The submersible propulsor unit of the invention comprises a cylindrical shroud having a water inlet and a water outlet, a propeller having a hub rotatably mounted within the shroud on a shaft, and an electric motor for driving the propeller that includes a rotor mounted around the periphery of the propeller, and a stator circumscribing the shroud, and a bearing assembly that includes means for circulating ambient water around the bearing surfaces to both lubricate and cool them. A stationary cover is detachably secured over the bearing assembly on the water inlet end of the shaft to provide easy access to the bearings in the bearing assembly. The vane members that concentrically mount the shaft within the interior of the shroud are all connected on the downstream side of the propeller to reduce the cavitation and resulting noise when the propeller rotates. The magnetization of the rotor is provided by a plurality of permanent magnets for both improved efficiency, and lower noise. A squirrel cage structure formed from damper bars and conductive wedges is integrated over the magnets of the rotor to assist in the starting of the motor, as well as to insulate the magnets from harmonic currents that could act to de-magnetize them.

Belt tensioner and method of making the same

Abstract: A belt tensioner and method of making the same are provided, the tensioner comprising a support for being fixed relative to a belt, a belt engaging arm carried by the support and being movable relative thereto, a spring operatively associated with the support and the belt engaging arm for urging the belt engaging arm relative to the support and against the belt with a force to tension the belt, the support comprising a shaft having a longitudinal axis, the belt engaging arm being rotatably mounted on the shaft, the arm having a bearing surface angled relative to the axis and the support having a bearing surface angled relative to the axis and facing the bearing surface of the arm, and a bushing disposed between the bearing surfaces and in engagement therewith to facilitate movement therebetween and to tend to prevent cocking of the arm on the shaft when the belt engaging arm is tensioning the belt.

Magnetic bearings for pumps, compressors and other rotating machinery

Abstract: A rotating machine having a rotor comprising a flexible shaft with a plurality of masses distributed along the shaft. Included within these masses are magnetic disks. Magnetic bearings are attached to the housing and coact to support the rotor in only a radial direction or in both radial and axial directions. Bearing sensors are used to measure the shaft position local to each bearing relative to a face of each bearing. Variable magnetic bearing parameters are controlled so as to change values of stiffness and damping of the magnetic bearings in response to the measurements from the bearing sensors. These controls can be direct analog circuitry, or digital components, or a combination of digital and analog components.

The Effects of Bearing Misalignment on the Non-Linear Vibration of Aero-Engine Rotor–Damper Assemblies

Abstract: The occurrence of non-linear vibration phenomena in aero-engine rotor-damper assemblies can seriously degrade performance. A range of assemblies incorporating one and two squeeze-Jilm dampers (SFDs) with ~arious static misalignments is investigated. Waterfall diagrams are constructed which demonstrate the effects of such misalignments and of damper support flexibility on the nature and severity of subsynchronous resonance and jump phenomena. Vibration signatures uf similar rotor-damper assemblies are shown to contrast strongly due to diferent accumulations of tolerances during manufacture,$tting and operation.

Radial rolling bearing

Abstract: A radial rolling bearing has cylindrical rolling bodies (2) which roll between an inner ring (11) and an outer ring (10). Individual spacers (1) are inserted between every two adjacent rolling bodies (2). The spacers (1) have contact surfaces (4) on both sides of their longitudinal center plane (3) and when the radial rolling bearing rotates, they are guided by means of one of their end sections (4a) on a running track of the inner ring (11) or outer ring (10). The spacer (1) is characterised in that a section (5) of the contact surfaces (4) has a convex, concave or flat profile on both sides of a sector (12) of the radial rolling bearing. When said section (5) is concave, its radius of curvature is substantially larger than the radius of curvature (8) of the rolling body (2). Because of the missing osculation between the spacer (1) and rolling body (2), an improved lubrification is achieved, and because of a defined point of application of force of the rolling body (2) on the spacer (1), the braking effect of the spacer (1) is compensated. Because of the reduced frictional heat, rolling bearings with such spacers can be driven at a very hig maximum speed of rotation.