Showing papers on "Bearing (mechanical) published in 1973"

Materials for Plain Bearings

Abstract: A bearing is interposed between two surfaces in relative motion to minimize the wear by one surface of the other and/or to reduce the friction between them. A plain bearing is made of, or is lined with, a material that achieves this object under conditions of sliding contact between it and one or other (or both) of the surfaces. This review is concerned with the materials of such sliding contact bearings only and does not cover the steel of rolling element bearings, which have their own peculiar property requirements.

Compound camshaft assembly for combustion engine - consists of shaft carrying separate bearings cams gearwheels etc fixed in correct positions

Abstract: The shaft may be a solid or hollow, profiled or round shaft. The various components such as bearing bosses, cams, eccentrics, gear wheels etc. are fixed appropriately, according to the application of the cam shaft. The shaft, bearings and cams may be in the same material. Alternatively some of all of the bearings and/or cams may be in a material which is different from that of the shaft. The bearings and/or cams may be in sintered material, forged sinter material, or cast or forged components or components made in any other way. The components may be fixed by adhesives, welding, hard-soldering, shrinking etc.

Bearing assembly systems

Abstract: A mid-span bearing support for the power take-off shaft of a fan type gas turbine engine is described. The power take-off shaft extends radially through frame struts in the core engine inlet and fan ducts of the engine. These struts are separated by a gap in which a bearing assembly is mounted to journal the power take-off shaft. This assembly includes a spring bellows which permits the height of the assembly to be reduced by a rotatable sleeve to permit retraction of interdigitating locating means in the installation and removal of the assembly. The spring bellows also provides sealing pressure of the assembly against opposed surfaces of the gap so that oil may flow through the struts and assembly for return to the engine's oil pump.

Thrust bearing lubricant measurement and balance

Abstract: A method of determining the axial thrust on a thrust bearing assembly having a fixed and a rotating component in which a lubricant is being forced between the mated faces of the respective components and where zones of pressure are built up during operation, comprising monitoring the pressure of the lubricant between the mated faces. The invention also provides for determining the axial thrust by measuring the pressure differential of the lubricant between the mated faces or as it enters therebetween and as it emerges from between said faces. To measure the axial thrust on a pair of opposing thrust bearing assemblies, the pressure differential of the lubricant between the respective mated faces of the two assemblies is obtained. The axial thrust measurement can be utilized in a method of adjusting the axial thrust on the bearing assemblies by changing manually or automatically a balancing apparatus separate from the thrust bearings and their lubricant and used to adjust the net thrust on the bearings in response to the respective pressure measurement. The invention also encompasses the combination of suitable pressure measuring devices with thrust bearing assemblies with balancing apparatus to carry out the above measurement and control methods.

Operating Torque of Tapered Roller Bearings

Abstract: A theoretical derivation has yielded a general expression for the operating torque of a tapered roller bearing under pure thrust load. Experimental data have been obtained to enable determination of the constant and exponents to make this expression usable. Further theoretical analysis has extended the use of the thrust load equation to pure radial and combined radial and thrust loads. Comparison of calculated and measured operating torques under radial load has verified the theoretical derivation. The bearing geometry variables from the basic torque equation have been combined into a G factor which represents the heat generation potential of a bearing. A typical bearing application illustrates use of the equations. Presented or on American Society of Lubrication Engineers paper at the ASME/ASLE International Lubrication Conference held in New York City, October 9–12, 1972

Arrangement for preloading bearings

Abstract: An arrangement for preloading a pair of axially spaced thrust sustaining antifriction bearings which are interposed in tandem between a pair of members in which one race of each bearing is abutted on one side by abutment means stationary on one of the members, while moveable abutment means on the other member are arranged in opposed relation to the other sides of the other races of the bearings. Load elements are interposed between the other races of the bearings and the moveable abutments and adjusted to compress the load elements axially and thereby exert a predetermined preload on the bearings. A feature of the present invention resides in the specific load elements and each of which is arranged so that axial compression thereof will cause the load element to undergo a first period of resilient deformation at increasing compressive force followed by a second period of plastic deformation at substantially constant compression force. In applying the preload to the bearings, the load elements are first compressed within the range of plastic deformation thereof and are then clamped in place between the bearings and the abutments therefor in a condition of resilient deformation. Precise and accurate preloading of the bearings can thus be accomplished without the necessity of resorting to expensive, highly accurate machining of the members in respect of the bearing engaging surfaces thereof.

Electromagnetic bearing means

Abstract: A contact-free bearing system for radially supporting a rotor, rotatable at high speed, with respect to a stationary member comprises a magnetic system including electromagnetic bearings. The electromagnetic bearings includes an endless ferromagnetic core carrying a spiral or toroidal winding which includes or acts as at least three separate coils. Electrical signals, dependent upon the radial deviation in the position of the rotor from a predetermined position are applied to said winding such that the coils produce magnetic fields which are applied to the rotor and are of different magnitude or direction.

Bearing Capacity of Footings in Plane Strain

Abstract: The experimental program to study plane strain bearing capacities of 3-in. and 6-in. model footings on dense sand is described. It is found essential that plane strain conditions are maintained in the test box, as deflections of the walls can cause a significant reduction in the ultimate bearing capacity and lodging of sand grains between the footing and the walls. Results also show that the ultimate bearing capacities for tough footings are only 10% higher than those for smooth footings and thus Meyerhof’s recommendation that 1/2 (Nγ) be used for smooth footings is not substantiated. Sokolovski’s method of solving the plasticity problem, as illustrated through the scaling procedure developed by Ko and Scott, produces the most accurate estimate of the smooth footing bearing values and appears to give a slightly conservative estimate of rough footing bearing values.

Bearing and bearing seal

Abstract: A bearing is disclosed comprising two relatively movable parts with one of them having an arcuate outer surface. A seal of special construction is used to entrap lubricant and keep out water and dirt. The seal has three sealing edges. Each of the three sealing edges contacts the movable member having the arcuate outer surface, providing two voids to entrap lubricant which acts to lubricate the sealing edges and provides additional sealing.

Journal and pilot bearings with alternating surface areas of wear resistant and anti-galling materials

Abstract: The journal and/or pilot bearings of a rotary cone earth boring bit are constructed to include alternating areas of wear resistant materials and anti-galling materials. The bearing matrix is formed by compressing a powdered alloy in the shape of the desired bearing element. The bearing matrix is sintered, thereby forming a porous bearing element. An anti-galling material is infiltrated into the porous matrix of the bearing element and the bearing element is hardened. The resulting bearing element includes areas of wear resistant materials and areas of anti-galling materials.

Bearing device for vertical-shaft rotary machines

Abstract: A bearing device comprising a bearing that supports the overall weight of the rotating parts of a vertical-shaft rotary machine and another associated rotary machine or machines and also bears downward thrust during operation, a bearing that controls radial displacement of the rotating parts, and a bearing that bears upthrust, or a thrust acting in the direction opposite to the direction for the first bearing. Of these bearings, those for controlling the radial displacement and for bearing the up-thrust are disposed close to each other to permit a reduction in the overall shaft length of the rotary machines and make the machines as a whole small in size and compact in construction.

Internal cylindrical bearing surfaces

Abstract: A method of producing a hard wearing bearing surface on a component such as a cylinder or cylinder liner, by pressing an accurately screened hard powder in liquid medium into engagement with the surface and on a helical path, the pressure and powder size being such that oil retaining micro-grooves are formed and also that a great number of powder particles, which particles virtually constitute the bearing surface, are embedded.

Rock bit with one piece body and depending arms

Abstract: A rotary rock bit is formed from a multiplicity of individual segments. At least one depending arm body is positioned in abutting relationship to a one piece bit body and welded thereto. A rotatable cutter is mounted upon the arm body and bearings are provided between the arm body and the cutter. A lubricant reservoir in the one piece body contains lubricant that is applied to the bearings between the cutter and the bearing pin. Passages extend from the lubricant reservoir through the arm body to the bearing area. A drilling fluid passage extends through the one piece body to allow a drilling fluid to be circulated through the bit during the drilling operation.

Conveyer belt roller

Abstract: A cylindrical roller rotatably supported on a stationary shaft and used as an idler in a conveyer belt arrangement, the roller including an end bearing supported relatively thick cylinder of a ceramic material with a very hard and smooth outer surface for contacting the conveyer belt, the roller being in the form of either a single elongated ceramic cylinder supported at its ends by end bearings, or a single elongated ceramic cylinder mounted on an end bearing supported steel sleeve, or a plurality of spaced relatively shorter elongated ceramic segments mounted on an end bearing supported steel sleeve or tube.

Composite expansion joint assembly

Abstract: A composite expansion joint assembly of alternating elastic sealing elements and rigid structural members mounted on support members slidably supported on bearing plates defining the bottom of the expansion groove and affixed to permanent slab supporting substructures therebeneath Hold-down members limit vertical displacement of the support members relative to the bearing plates

Pad construction for tilting pad thrust bearing

Abstract: A tilting pad for a thrust bearing is formed of steel and faced with a layer of graphite-fiber composite material. This provides good bearing properties, a low coefficient of thermal expansion parallel to its surface, and a low coefficient of thermal conductivity transverse to its surface. The facing material insulates the bearing pad from oil-sheer heat and thus increases the load capacity of the pad by reducing the tendency to bend which is customarily caused by a temperature differential across a pad. The facing material is made of criss-crossed layers of graphite fibers embedded in a resin, the fibers being oriented in directions substantially parallel with the surface of the steel pad.

Analysis of an Arched Outer-Race Ball Bearing Considering Centrifugal Forces

Abstract: A Newton-Raphson method of iteration was used in evaluating the radial and axial projection of the distance between the ball center and the outer raceway groove curvature center (V and W). Fatigue life evaluations were made. The similar analysis of a conventional bearing can be directly obtained from the arched bearing analysis by simply letting the amount of arching be zero (g = 0) and not considering equations related to the unloaded half of the outer race. The analysis was applied to a 150-mm angular contact ball bearing. Results for life, contact loads, and angles are shown for a conventional bearing (g = 0) and two arched bearings (g = 0.127 mm (0.005 in.), and 0.254 mm (0.010 in.)). The results indicate that an arched bearing is highly desirable for high speed applications. In particular, for a DN value of 3 million (20,000 rpm) and an applied axial load of 4448 N (1000 lb), an arched bearing shows an improvement in life of 306 percent over that of a conventional bearing. At 4.2 million DN (28,000 rpm), the corresponding improvement is 340 percent. It was also found for low speeds, the arched bearing does not offer the advantages that it does for high speed applications.

Drill bit bearings

Abstract: A roller drill bit of the type in which a rotatable cutter is supported against radial and thrust loading on a shaft in which thrust and other frictionally engaging bearing surfaces between the cutter and the shaft are established by uncarburized surface portions in either the cutter of the shaft which are otherwise formed of carburized or case hardened steel thereby avoiding heat cracks and spalling of the steel between the bearing surfaces.

Full complement bearing having preloaded hollow rollers

Abstract: This disclosure relates to a full complement bearing and the method of forming the same wherein the rollers of the bearing are hollow and are installed between the bearing races in a preloaded condition. Further, the rollers have the end portions thereof relieved so that only the central portion of each roller is cylindrical. Such a roller bearing produces highly desirable and unexpected results. First, the runout of the bearing is at a minimum. In fact, utilizing lower grade components, a full complement hollow roller bearing formed in accordance with this disclosure will have the superior minimum runout of a much higher grade bearing utilizing solid rollers. In addition, the life expectancy of the full complement bearing is much greater than that of like full complement bearings having solid rollers.

Bearing for high speed rotary shafts

Abstract: System for journalling a high speed rotary shaft in which a spherical fluid dynamic cap bearing is adapted to receive an end of the shaft. A magnet arrayed in the vicinity of the cap exerting a force axially on the shaft. The shaft is provided with magnetic material cooperation with the magnet, so that that the shaft is drawn and/or pushed into the bearing.

Roller for a pressure treatment of webs

Abstract: In order to avoid friction in the transmission of the flexure compensating forces via the piston and bearing shoe units, a chamber is formed between the bearing shoe and piston to receive a pressure medium for partially relieving the joint between the bearing shoe and piston of load. An annular seal is also provided between the bearing shoe and piston in the plane of the pivot point of the joint to seal the relief pressure chamber.

Rack and pinion assemblies

Abstract: Rack and pinion assemblies employ a bearing assembly which is provided for rotatably mounting the pinion member in a housing member, the bearing assembly comprising three generally annular bearing elements which substantially encircle the pinion member. A first of the bearing elements is carried by one of the pinion or housing members and the second and third of the bearing elements are carried in an axially disposed relationship by the other of these members. The first element has a first bearing surface which engages axially between and slidably abuts substantially complementary second and third bearing surfaces of the second and third elements, respectively. The area of abutment between the respective surfaces extends both radially and axially so that the abutment restrains both radial and axial displacement of the first bearing element relative to the other two. The bearing assembly may be mounted in the rack and pinion assembly on a piecemeal basis, or may advantageously be provided as a pre-formed, pre-loaded unit whereby loading adjustments do not depend upon the skill of an operator during assembly of the rack and pinion.

Roller bearing of superior run-out characteristics

Abstract: This disclosure relates to a roller bearing assembly which, when used to support a shaft for rotation, unexpectedly greatly reduces the run-out of the shaft even as compared to previous super precisions roller bearings. It has been discovered that if hollow rollers are substituted in a roller bearing for solid rollers and the hollow rollers are positioned between an outer race and a shaft or inner race in a preloaded condition with the allowable flexure of the rollers being at least slightly greater than the variations in radial spacing between the races, the run-out of a shaft axis so supported is greatly reduced. Further, the life of such a bearing is greatly extended. In addition, less precisions rollers may be utilized.