摘要:

An experimental and mathematical study of elastohydrodynamic film formation is described for a rolling four-ball configuration utilizing steel bearing balls. Wear rates are determined in the microgram range, using a radiotracer tagged ball. Existence and interruptions of elastohydrodynamic films are observed by measurement of electrical conductivity through the Hertzian contact. Surface microgeometry of the rolling tracks on the balls is statistically analyzed by processing electrical analogs of surface profiles through on-line computing equipment. Defining electrical contacts as asperity approaches through a separating film, the average duration and frequency of such approaches is computed from surface microgeometry statistics. A comparison of computed and observed values of contact conductivity parameters shows good order of magnitude agreement and yields estimates of average film thickness as a function of speed and load which agree, satisfactorily with the order of film thickness predicted by elastohydrodynamic theory. Significant wear is shown to occur only in regimes where the film is interrupted and to become progressively more rapid as the severity of asperity contacts increases with decreasing speed.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Rochester, New York, October 15–17, 1963.

ISSN:0569-8197    

DOI:10.1080/05698196408972041

出版商:Taylor & Francis Group    

年代:1964

数据来源: Taylor

摘要:

The design of back-up roll bearings in cluster-type rolling mills has, historically, been dictated by past engineering trial and error experience. Thus, to cause the bearings to act, as nearly as practicable, similarly to conventionally supported bearings, the outer ring section is usually made very heavy precluding large ring deflections.

ISSN:0569-8197    

DOI:10.1080/05698196408972042

出版商:Taylor & Francis Group    

年代:1964

数据来源: Taylor

摘要:

A study was made of the surface temperatures generated by friction in a sliding system—a fixed constantan ball riding on a rotating steel cylinder. Using the principle of the Herbert-Gottwein dynamic thermocouple, time-average as well as instantaneous surface temperatures were determined. Some measurements were also made with imbedded thermocouples, and advantages and limitations of both methods are discussed.

ISSN:0569-8197    

DOI:10.1080/05698196408972043

出版商:Taylor & Francis Group    

年代:1964

数据来源: Taylor

摘要:

Oils containing polymers have been shown to give better bearing performance—lower friction and lower wear—than straight mineral oils of the same low-shear viscosity, in spite of their non-Newtonian character. This unexpected behavior has been investigated further in studies on solutions of different polymer types, using a range of molecular weights and concentrations for each type and blending all solutions to the same low shear viscosity. The viscosity and elasticity of these solutions were measured at different rates of shear in an ultrasonic crystal viscometer. The governing parameter controlling bearing performance appears to be the recoverable shear, which is related to the elastic modulus of the system. Polymer type, also appears to be important in determining the critical value of recoverable shear required for good bearing performance.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Rochester, New York, October 15–17, 1963.

ISSN:0569-8197    

DOI:10.1080/05698196408972044

出版商:Taylor & Francis Group    

年代:1964

数据来源: Taylor

摘要:

This paper contains the description of a solution of the problem of self-acting, gas-lubricated, partial-arc, finite length journal bearings for steady-state conditions.

ISSN:0569-8197    

DOI:10.1080/05698196408972045

出版商:Taylor & Francis Group    

年代:1964

数据来源: Taylor

摘要:

The results of an exploratory experimental investigation of externally pressurized, condensing vapor lubricated, thrust bearing behavior are described. The results indicate that bearing load carrying capacity using vapor lubricant is somewhat lower than would be expected from a comparable single-phase compressible lubricant. Bearing performance is strongly dependent on the rate at which heat is removed from the lubricant film by the bearing surfaces because of progressive condensation of the lubricant flowing over the cooled surfaces. Interaction of thermodynamic and fluid flow processes results in a well-defined load capacity for the vapor lubricated bearing and leads to an abrupt collapse of the bearing if the load limit is exceeded.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Rochester, New York, October 15–17, 1963.

ISSN:0569-8197    

DOI:10.1080/05698196408972046

出版商:Taylor & Francis Group    

年代:1964

数据来源: Taylor

摘要:

The performance of hydraulic systems at high temperatures is particularly sensitive to the properties of the hydraulic fluids. The effects of stability, viscosity, compressibility, volatility, gas solubility, and lubrication on hydraulic component and system performance are discussed. These properties singly and in combination affect many aspects of hydraulic system operation. The reaction of fluids to high temperatures causes significant changes in hydraulic performance.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Rochester, New York, October 15–17, 1963.

ISSN:0569-8197    

DOI:10.1080/05698196408972047

出版商:Taylor & Francis Group    

年代:1964

数据来源: Taylor

摘要:

This paper is a reasonably complete presentation of the formulation, the physical and chemical properties, and the pump loop behavior of a deep-dewaxed mineral oil, MLO 60–294. Properties given include: (a) viscosity and bulk modulus as functions of both temperature and pressure, (b) specific heat, density, thermal expansion, vapor pressure, and thermal conductivity as functions of temperature, and (c) pour, cloud, flash, and fire points. The behavior of this fluid in one pump loop to 700 F, and in a second loop to 600 F, is discussed. Excellent fluid performance was obtained in these pump loops at 400, 500, 550, and 600 F; however, the fluid degraded rapidly at 700 F.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Rochester, New York, October 15–17, 1963.

ISSN:0569-8197    

DOI:10.1080/05698196408972048

出版商:Taylor & Francis Group    

年代:1964

数据来源: Taylor

摘要:

A laboratory apparatus has been designed for the evaluation of materials and lubricants in sliding friction and for the prediction of performance of a particular type of hydraulic pump.

ISSN:0569-8197    

DOI:10.1080/05698196408972049

出版商:Taylor & Francis Group    

年代:1964

数据来源: Taylor

摘要:

High-temperature fluid lubrication is influenced by many factors. Among these factors are the products of degradation of the fluid. Operating at bulk temperatures well below the initial decomposition point, equipment hot spots produce temperatures that result in small but significant amounts of fluid degradation. The material thus formed affects the lubricating characteristics of the fluid. Results obtained with a polyphenyl ether illustrate somewhat of an extreme of such an effect. Likewise, fluid decomposition products appear to influence lubrication with both mineral oils and silicones. Intensive study of this phenomenon is suggested as a means of achieving a sounder understanding of the mechanism of lubrication.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Rochester, New York, October 15–17, 1963.

ISSN:0569-8197    

DOI:10.1080/05698196408972050

出版商:Taylor & Francis Group    

年代:1964

数据来源: Taylor