Showing papers on "Bearing (mechanical) published in 1991"

Fundamentals of fluid film lubrication

Abstract: 1: Introduction 2: Bearing Classification and Selection 3: Surface Topography 4: Lubricant Properties 5: Bearing Materials 6: Viscous Flow 7: Reynolds Equation 8: Hydrodynamic Thrust Bearings - Analytical Solutions 9: Hydrodynamic Thrust Bearings - Numerical Solutions 10: Hydrodynamic Journal Bearings - Analytical Solutions 11: Dynamically Loaded Journal Bearings 12: Hydrodynamic Journal Bearings - Numerical Solutions 13: Hydrodynamic Squeeze Film Bearings 14: Hydrostatic Lubrication 15: Hydrodynamic Bearings - Considering Fluid Inertia 16: Gas-Lubricated Thrust Bearings 17: Gas-Lubricated Journal Bearings 18: Hydrodynamic Lubrication of Nonconformal Surfaces 19: Simplified Solutions for Stresses and Deformations 20: General Solution for Stresses and Deformations in Dry Contacts 21: Elastohydrodynamic Lubrication of Rectangular Conjunctions 22: Elastohydrodynamic Lubrication of Ellipitcal Conjunctions 23: Film Thicknesses for Different Regimes of Fluid Film Lubrication 24: Rolling-Element Bearings 25: Additional Elastohydrodynamic Lubrication Applications 26: Non-Newtonian Fluid Effects in Elastohydrodynamic Lubrication 27: Thermo Elastohydrodynamic Lubrication.

Diamond thrust bearing and method for manufacturing same

Abstract: A diamond thrust bearing and method for manufacturing the diamond thrust bearing wherein diamond bearing pads are interference fitted at ambient temperatures into a plurality of equidistantly spaced bearing pad recesses located in a circle in a receiving surface of a bearing pad retainer. The bearing faces of the diamond bearing pads are located coplanar with a predetermined common bearing plane by pressing the bearing faces into the bearing pad retainer with a ram and inflexible pressing plate until the pressing face of the pressing plate is stopped by a press stop block. The diamond thrust bearing manufactured using the method will be free from heat induced stresses that cause bearing face misalignment.

Air bearing slider

Abstract: PURPOSE: To obtain the best characteristics for reading and writing by separating a air bearing region into two regions by a central non-air bearing region. CONSTITUTION: An air bearing part 30 of a slider is separated into a first region 31 and a second region 32 by a central region 33. Bart or the whole of the region 31 and the region 32 are formed of one or more pads including air bearing surfaces 35, 36. The region 33 includes substantially a notched non-air bearing surface 34 between bearing surfaces 35 and 36. A surface 34 is notched by sufficient depth for making it substantially a non-air bearing separated from the bearing surfaces 35, 36. Also, a piezoelectric element 40 is provided in the region 33, and when the element is excited by an electric input signal, it can cause deformation in the region 33. When the region 33 is deformed, relative opposite angles of the bearing surfaces 35, 36 are varied, height of the bearing surface 36 is varied. When a convex projection part is formed by deforming the region 33, height of the region 32 is decreased. The region 33 has convex projection when the region 33 is curved to a magnetic surface side.

Experimental Study of Friction‐Pendulum Isolation System

Abstract: A shake‐table study of the friction‐pendulum isolation system, installed in a six‐story, quarter‐scale, 52‐kip model structure, is presented. Two bearing materials are studied, one with a peak friction coefficient of 0.075 and another of 0.095. In both cases, the isolation system has a rigid‐body mode period of 1 sec. The isolated structure is found to be capable of withstanding strong earthquake forces of different frequency content. In tests with the El Centra motion, the isolated structure sustains, without any damage, a peak ground acceleration six times greater than what it could under fixed‐based conditions. It is found that the bearing displacements are low and that the permanent bearing displacements at the end of free vibration are very small, in general, not exceeding 6% of the bearing design displacement. The system is shown to have quantifiable properties, and analytical techniques are presented that provide accurate prediction of the response.

Rotary anode type X-ray tube

Abstract: In a rotary-anode type X-ray tube, a rotary-anode is fixed to a cylindrical rotary structure, and a columnar stationary shaft is fitted in the rotary structure. A gap is formed between the rotary structure and the stationary shaft. The gap is filled with a liquid metal lubricant. Spiral grooves are formed in part of the outer surface of the stationary shaft to form a radial sliding bearing between the stationary shaft and the rotary structure. Spiral grooves are formed in the end faces of the stationary shaft to form a thrust sliding bearing between the stationary shaft and the rotary structure. A recess is formed in the stationary shaft to communicate with gaps in the radial sliding bearing. A lubricant storage chamber for storing the liquid metal lubricant is formed in the stationary shaft along the center axis. The storage chamber communicates with communicating holes which radially extend to be open to an outer surface region, of the stationary shaft, in which no spiral grooves are formed. With this structure, a sufficient amount of liquid metal lubricant required for a long-term operation of the sliding bearings can be stored in the X-ray tube, thereby maintaining a stable dynamic pressure type sliding bearing operation for a long period of time.

Through hole mounting of integrated circuit adapter leads

Abstract: An adapter that is to be conneced to contacts on a mother circuit surface The adapter has a circuit bearing element, such as a printed circuit board, with connection sites that are connected to metalized holes opening onto its top side Leads are anchored (eg, by soldering) in the holes and bent down around the edge of the top side of the circuit bearing element to below it, and may be connected to the contacts on the mother circuit surface The leads may be provided to the circuit bearing element, using lead frame elements provided in a lead frame, by bending the lead frame elements, soldering them in holes in the circuit bearing element, bending the soldered leads down around the edge of the top surface of the circuit bearing element and below it, and removing a side frame portion from the bent lead frame Bending and cutting of the leads may be performed in a single operation with a single tool

Design Considerations for Cushion Form Bearings in Artificial Hip Joints

Abstract: Lubrication mechanisms and contact mechanics have been analysed in a new generation of ‘cushion form’ bearings for artificial hip joints, which comprise low elastic modulus layers on the articulating surfaces. Comparisons have been made with ‘ hard’ bearings used in existing prostheses and also with the natural hip joint. Lubricating film thicknesses are enhanced by larger contact areas and lower contact pressures. For a fixed contact area, simultaneous changes in layer thickness and radial clearance have been shown to have a small effect on elastohydrodynamic film thickness. Hard bearings designed with the same contact area as the cushion bearings produced a similar film thickness, but lubricant film thickness is not optimized in current designs. The main advantage of using a cushion bearing with low elastic modulus layers was found to be associated with microelastohydrodynamic lubrication. Careful selection of the elastic modulus is important in order to ensure that this lubrication regime was effective...

Tribology: Principles and Design Applications

Abstract: Surface properties and surface contact friction wear tribological properties of solid materials fluid lubricated thrust bearings fluid lubricated journal bearings the lubrication of highly loaded contacts bearing selection lubricating systems.

Journal bearing arrangement

Abstract: A planetary gear system includes a plurality of planet gears, each having a journal bearing and a pin, end supported in a planet carrier Each pin has a small diameter central portion axially extending for end support A larger diameter outer portion is integral with the central portion at an inboard merged zone, and has cantilever sections extending outboard from the merged zone Each pin is sized such that bending of the merged zone in one direction is countered by bending of the cantilever sections in the other direction to achieve a substantially linear bearing surface under load

Variable compression ratio device for internal combustion engine

Abstract: PURPOSE:To improve reliability and durability of locking actuation by rotatably providing an eccentric sleeve at one of support parts of connecting rods, and providing an eccentric sleeve lock means formed of a stopper pin and a lock pin which moves in the axial direction of the eccentric sleeve. CONSTITUTION:At a support part of a connecting rod, there are provided an eccentric sleeve 5 which mutually makes eccentric a bearing hole of the connecting rod and a support shaft which penetrates the bearing hole. A lock pin 32 and a stopper pin 31 are provided as a lock means 30 of the eccentric sleeve 5. Rotation of the eccentric sleeve 5 is stopped when it abuts against the stopper pin 31. After the lock pin 32 is moved in the axial direction of the eccentric sleeve 5, the pin 32 is engaged with engaging parts 5a-5c formed at the sleeve 5 and fixed.

Ball and roller bearings and bearing components

Abstract: Improved structures in bearings operable to receive and support shafts or members which are supported for rotation on shafts or pins are disclosed. In one form, just the inner cylindrical surface of a solid bearing made of metal or hard ceramic material is coated with a synthetic diamond material deposited in situ therein as carbon atoms by means of high energy radiation, which also serves to form synthetic diamond structures of layers of such carbon atoms so deposited. In another form, the entire race of a multiple part bearing is coated with synthetic diamond material. In a third form, a rolling member type bearing, such as a ball or roller bearing, is provided containing an inner race, an outer race, and a plurality of balls, rollers, or other rolling members supported between the inner and outer race. In certain instances, the rolling members are retained by means of a cage supported therebetween. The rolling members, inner and outer races, and, when employed, the cage, are all coated with hard synthetic diamond material deposited in situ thereon as described. Alternatively, select portions of the components of the bearing may be coated to the exclusion of other portions thereof. In all forms, the synthetic diamond material coating may be overcoated with thin layers of chromium, chromium alloys, or similar materials.

Hydrodynamic bearings having beam mounted bearing pads and sealed bearing assemblies including the same.

Abstract: A hydrodynamic thrust, journal or combined radial and thrust bearing which may be mounted within a sealed housing assembly (1) which can, for example, be used to replace rolling element bearings. The bearing can be designed for mounting to either the shaft or housing. If mounted for rotation with the shaft, the bearing pads (12) move relative to a smooth support surface. The bearing includes a bearing pad structure (1, 14, 126) that may change shape and move in any direction (six degrees of freedom) to optimize formation of a converging wedge for hydrodynamic operation, equalization of load on the bearing pads (12) in thrust bearings and to adjust for any shaft misalignment.

Aluminide coated bearing elements for roller cutter drill bits

Abstract: A roller cutter drill bit (10) has separate bearing elements (82, 84, 86) positioned between a journal (20) and a roller cutter (60) mounted for rotation on the journal (20). The bearing elements (82, 84, 86) are formed of a superalloy material and the bearing surfaces of the bearing elements (82, 84, 86) have an aluminide coating applied thereon to form a bearing surface stable at operating temperatures over 500 F. and as high as 1000 F.

Lightweight engine turbine bearing support assembly for withstanding radial and axial loads

Abstract: A gas turbine engine incorporates a bearing support assembly which mounts an inner annular bearing arrangement in radially spaced relation inwardly from a stationary outer casing. The bearing arrangement, in turn, mounts a turbine rotor within the outer casing for rotation about a central axis relative to the outer casing. A row of stationary stator vanes are fixedly attached to an extend radially inwardly from the outer casing toward the central axis. The bearing support assembly includes an inner ring structure extending about and mounting the inner bearing arrangement, elongated tie rods each having opposite outer and inner end portions and being disposed in circumferential spaced relation to one another and extending through the stationary vanes in radial relation to the central axis and between the outer casing and inner ring structure, and fastening elements fixedly clamping the outer casing and inner ring structure respectively to the outer and inner end portion of the tie rods such that the tie rods, outer casing and inner ring structure act together as a unit to uniformly distribute bearing-induced radial loads and to withstand bearing-induced radial loads in both tension and compression. An annular shell structure is disposed between and fixedly interconnects the inner ring structure and stationary vanes such that the annular structure, inner ring structure and stationary vanes act together as a unit to withstand axial loads induced by differences in air pressure existing axially through the outer casing.

Process for making a bearing collar and bearing assembly equipped with such a collar

Abstract: Bearing assembly carrying a radial collar (10) for retaining an interior ring element (4) of a bearing having two rows of rolling bodies (2) and which has at least one fastening flange (5), in which the inner face of collar (10) extends axially under ring element (4) by an axial support edge.

Dual-guided exercise apparatus

Abstract: An exercise apparatus for safely assisting a person to lift weights which incorporates concurrently functioning vertical and horizontal guidance mechanisms. The exercise apparatus is comprised of a frame including two rectangularly shaped parallel aligned structures having four horizontally extending support members, a lifting bar, a horizontal guidance mechanism, and a vertical guidance mechanism. The horizontal support members function also as the horizontal guidance bars. Each horizontal guidance bar has a bearing block slidably attached thereto via a linear bearing. Pairs of bearing blocks are connected to the ends of two vertically extending guidance bars which move horizontally via their attachment to the bearing blocks. Similarly, the vertical bars have bearing blocks with linear bearings attached thereto which are also connected to the ends of the lifting bar. The lifting bar moves vertically along the vertical bars and moves horizontally via the vertical bars' connections to the horizontally moving bearing blocks. The vertical bars are pivotally attached to the horizontal bearing blocks at their bottom end to compensate for any minor bearing misalignment. The apparatus can be used for a variety of exercises where the weight is pushed or pulled in the vertical direction. The horizontal guidance feature allows the apparatus to adjust to the human body's natural propensity to pull towards or push away while pushing up or pulling down, the attached weight.

Integral motor propulsor unit for water vehicles with plural electric motors driving a single propeller

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, in one embodiment, 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 both 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. In one embodiment, the propulsor unit has a single propeller driven by two identical side-by-side motor assemblies. This arrangement provides added reliability while retaining mechanical simplicity and low cost and weight as compared with a multipropeller propulsor unit.

Turbo molecular pump

Abstract: A turbo molecular pump includes a magnetic bearing system which includes a rotor having an impeller connected to a shaft and a motor. A stator is positioned between the shaft and the impeller. Radial magnetic bearings, an active axial magnetic bearing and emergency bearings are each provided between the rotor and the stator. The radial magnetic bearings include passive magnetic bearings provided on the rotor and the stator respectively. The axial magnet bearing is disposed in the vicinity where the impeller is connected to the shaft. The emergency bearings are disposed on a low vacuum side with one emergency bearing being positioned near the axial magnetic bearing. A diameter of the shaft is made smaller than an inside diameter of the emergency bearing near the axial magnetic bearing. By this arrangement, only one control axis is necessary for controlling the position of the rotor. Disassembling of the shaft and impeller is easy and contamination of the high vacuum side can be prevented.

Antifriction bearing assembly speed sensor

Abstract: An antifriction bearing assembly comprises a stationary outer race and a rotatable inner race with two annular rows of rolling elements between the races. A sensor assembly is mounted in the outer race so as to position a sensor between the races and the two rows of rolling elements, and an encoder is mounted on the inner race between the rows of rolling elements. Several sensor assembly and encoder configurations are included.

Stacked magnet superconducting bearing

Abstract: In a superconducting bearing, flux density and flux density gradient are increased between a magnetic source and a member of superconducting material. A plurality of magnets are magnetized end-to-end and stacked side-by-side in alternating polarity. Non-magnetic shims are disposed between the magnets. Flux lines flow between the ends of adjacent magnets and communicate with the member. Resulting is higher bearing load capacity and stiffness. When the member is made from a Type II superconducting material, the bearing provides support in both the radial and axial directions.

Squeeze film damper seal

Abstract: Shaft damper bearing utilizing spaced apart piston ring seals to seal off an annular squeeze film space between the rings, includes diagonal surface cross-section ring grooves in the bearing housing with diagonal cross-section rings in the housing grooves adapted to engage a bearing support undergoing radial motion in the housing.

Study of sliding bearing and helical-steel-spring isolation system

Abstract: A sliding isolation system consisting of Teflon disc bearings and helical steel springs is described. The springs carry no vertical load and provide bilinear restoring force without hysteresis when deformed in shear. The Teflon disc bearings carry the entire weight of the structure. The isolation system is designed so that the mobilized peak frictional force is larger, by at least a factor of two, than the peak restoring force. Under these conditions the system has a low sensitivity to the frequency content of the input. The system has been evaluated in shake‐table tests of a six‐story, quarter‐scale, 52‐kip (230‐kN) model structure, and is capable of withstanding strong earthquake forces of significant differences in frequency content. Furthermore, the springs are effective in controlling bearing displacements. Also, tests have been carried out without restoring force. In this case excessive permanent displacements are recorded as a result of a small accidental inclination of the sliding bearings. Finall...

Rotating magnetron incorporating a removable cathode

Abstract: A rotatable magnetron having a cathode (64) and a bearing assembly (10) wherein the cathode (64) may be removed from a coating chamber (42) while the bearing assembly (10) remains in place.

Thrust bearing arrangement for a power tool transmission

Abstract: In the compact transmission of a hand-held reciprocating power saw, conversion of rotary to reciprocating motion is through a speed reducing bevel gear set (crown wheel and pinion) closely coupled by an eccentric drive pin in the crown wheel to a reciprocating saw blade carrier bar. A guide or bearing plate extending between the crown wheel and the saw blade carrier bar does double duty, guiding and supporting the saw blade carrier bar on one side and, on its opposite side, providing a thrust surface for the crown wheel. The crown wheel engages the guide plate through a thrust ring about equal in diameter to the diameter of the crown wheel. In this way, the shallow crown wheel may be positioned, supported and stabilized entirely by two simple bearings--a large diameter plain thrust bearing of essentially no radial capacity and a short radial bearing subject to virtually no bending or thrust loads. In an alternative embodiment the guide plate is eliminated and the reciprocating carrier bar receives the thrust load of the crown wheel.

Analysis of rolling element bearings

Abstract: Part 1 Types of rolling bearings: ball bearings, roller bearings. Part 2 Geometric relation in rolling bearings: ball bearings roller bearings. Part 3 Contact pressure and deformation: Hertzian theory of the elastic contact contact pressure and deformation in rolling bearings stress distribution below contact surface influential factors on contact stress. Part 4 Load distribution in rolling bearings: load-deflection relation load distribution in radial bearings bearings under axial load bearings under combined radial and axial loads bearings under combined radial, axial and moment loads. Part 5 Kinematics of rolling bearings: simple kinematic relations general kinematic relations in ball bearings. Part 6 Elastohydrodynamic lubrication in rolling bearings: the theory of elastohydrodynamic lubrication calculation of film thickness in roller bearings calculation of film thickness in ball bearings estimation of film thickness in rolling bearings. Part 7 Contact fatigue: the maximum dynamic shear stress theory of contact fatigue engineering model of contact fatigue failure statistical fracture theory of contact fatigue influential factors on contact fatigue. Part 8 Dynamic load rating and equivalent dynamic load: dynamic load rating equivalent dynamic load modification of life calculation. Part 9 Statistical treatments of life experiments: parameter estimations of Weibull distribution treatment methods of accelerated tests. Part 10 Static load rating of rolling bearings: permanent deformation in rolling bearings static load rating of rolling bearings equivalent static load of rolling bearings. Part 11 Life calculation of rolling bearings and their development: life calculation of rolling bearings development of life calculation methods life calculation of linear motion ball bearings life calculation of rolling screws calculation of wear life of bearings. Part 12 Grease life in rolling bearings: calculating methods for grease life influential factors on grease life. Part 13 operating performance of rolling bearings - stiffness: deflection and stiffness of rolling bearings preloading for rolling bearings limiting axial load of ball bearings. Part 14 Operating performance of rolling bearings - friction moment: formation mechanisms of friction moments in rolling bearings calculation of friction moment in rolling bearings. Part 15 Optimization of design for rolling bearings: basic concepts of mathematical optimization of design objective functions of design optimization for rolling bearings applications of optimization methods in bearing design. Part 16 Computer aided design of high speed ball bearings: raceway control theory design of elastohydrodynamic lubrication applications of computing models. Part 17 Computer aided design of high speed roller bearings: design theory of elastohydrodynamic lubrication influence of misalignment on cylindrical roller bearings.