摘要:

The dynamic equations of motion of a ball-bearing separator are solved with a six degree-of-freedom model and vector matrix algebra. The dynamic model includes the effects of inelastic collisions of the separator with the balls and/or races, and also slip of the balls on the races. The digital computer model predicts separator motions, impact forces, frequencies, and all dynamic variables such as accelerations, velocities, and energy losses. The model of the ball bearing is simplified, in ways that do not significantly affect the separator dynamics, for the sake of making the analytical model and the resulting digital computer program cost effective. The analysis is adaptable to optimization of separator designs and improving performance of bearings with separator dynamic instability problem.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981622

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The dynamic equations of motion of ball-bearing separators were solved using certain simplifications to make computer analysis feasible from a cost point of view. A typical turbine engine bearing, employing solid lubrication, was used for a trade-off and optimization study of ball-separator design. The effects of varying geometric parameters of the separator were studied, along with different friction and traction coefficients and operating speeds of the bearing. The computer analysis indicated that the ball-pocket collision forces are significantly affected by the geometry of the ball separator (particularly the working clearances), and are also sensitive to the traction and friction coefficients of the materials and lubricant system.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981623

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper discusses the various wear mechanisms involved with single-crystal ceramic materials in indentation and in sliding contacts. Experiments simulating interfacial events have been conducted with hemispherical, conical, and pyramidal indenters (riders).

ISSN:0569-8197    

DOI:10.1080/05698198508981624

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A temperature analysis of dry sliding fully plastic contact is extended to calculate the asperity temperatures between a sliding lubricated rigid smooth plane and a stationary elastic rough surface. First, surface roughness is generated numerically to have a Gaussian height distribution and a bilinear autocorrelation function. Lai and Cheng's elastic rough contact computer program is then used to determine the asperity contact loads and geometries of real contact areas. Assuming different frictional coefficients for shearing the lubricant film at the noncontact areas, shearing the surface film at the asperity contacts and shearing the oxide film as the asperity temperature exceeds a critical temperature, asperity temperature distributions can be calculated. Eight cases in Durkee and Cheng's scuffing tests of lubricated simple sliding rough contacts are simulated by using 20 computer-generated rough surfaces. The results show that scuffing is correlated to high-temperature asperities which are above the material-softening temperature.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981625

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Air-release values of mineral base oils are adversely affected by certain minor constituents which are preferentially adsorbed over the dispersed air bubbles. Such components of a few selected base oils having high air-release values were isolated by adsorbent treatment and solvent-extraction steps. Among the various adsorbents and solvents tried, silica gel and isopropanol were found to be the most effective in improving air-release values of the base oils studied. The components of base oils so separated were further fractionated and analyzed. The results indicated that the fraction of the base oils responsible for poor air release is rich in aromatics, naphthenes, nitrogen, and sulfur.

ISSN:0569-8197    

DOI:10.1080/05698198508981626

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

An experimental technique to measure creep properties in compression ofthinpolymeric film is developed. An analysis is derived to calculate creep compliance and elastic and creep strains in compression of the thin films. Measurements were made on five typical magnetic inks and the poly (ethylene terephthalate) substrate used in magnetic tapes. Modulus of inks as measured by the developed technique is an order of magnitude lower than the bulk modulus measured by other techniques. This indicates that the ink-film surface is mechanically different from that of the bulk of the film. No significant changes in mechanical properties between film surface and bulk were seen in the case of PET films. Calendered magnetic inks showed slightly lower creep compliance than uncalendered films. Recovery experiments showed that the ink surface goes through some permanent deformation which would affect tape friction.

ISSN:0569-8197    

DOI:10.1080/05698198508981627

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The effects of variations in lubricant supply pressure on the characteristics of two-lobe non-preloaded bearings are examined. The bearing solutions are obtained by an approximate method developed earlier that includes viscosity variation due to thermal effects. Theoretical results are presented in nondimensional form and dimensional examples are given, including a comparison with published experimental data. The magnitude of the supply pressure is seen to have significant effects on the operating eccentricity, lubricant flowrate, temperature rise, stiffness and damping coefficients, and rigid rotor stability threshold over a wide range of speed conditions.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981628

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The abrasion rate of an alloy has generally been found to be a function of the abrasive particle size, decreasing rapidly for particle sizes below about 100 microns, and the same general behavior is found for erosion by solid particle impact. Most previous investigations of this effect have been confined to single-phase alloys or steels having second-phase particles which are small relative to the size of the surface grooves. In the present study, a dual-phase powder-metallurgy alloy (Stellite 19) was abraded with both quartz and alumina abrasives using a low-stress abrasion test, and 1020 steel specimens were also included as a comparative standard. The quartz abrasive particles have a hardness intermediate between that of the Stellite 19 matrix and the large, hard Cr-rich carbides which are contained in the microstructure, whereas the alumina particles have a hardness comparable to that of the carbides.

ISSN:0569-8197    

DOI:10.1080/05698198508981629

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The Composition of the surface coatings obtained by running commercially available crankcase oils in the four-ball wear tester was determined using a scanning Auger microprobe. The films were 300–500 nm thick, highly heterogeneous, and composed primarily of iron, oxygen, and calcium, plus smaller amounts of zinc, phosphorus, sulfur, and carbon. There were two types of regions within the wear scars, one rich in sulfur and either iron or zinc, the other in calcium, phosphorus, and oxygen. Due to low carbon levels and evidence from other investigations, the sulfur-rich regions were thought to contain a combination of iron and zinc sulfides. The composition of the phosphorus compounds could not be determined, but the data suggest that phosphorus was combined with oxygen as phosphate or phosphate-like species.

ISSN:0569-8197    

DOI:10.1080/05698198508981630

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper presents an experimental study of the characterstics of a ferromagnetic linear vacuum seal with rotation. This seal was developed with respect to the results obtained from observing the behavior of ferromagnetic fluid with a two-dimensional linear seal model apparatus.

ISSN:0569-8197    

DOI:10.1080/05698198508981631

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor