摘要:

An asymptotic analysis of the three-dimensional motion of a piston ring in its groove is presented, with appropriate nondimensional scaling. It is shown that the calculations in the literature use both a regular expansion and a multiple time scale expansion. The analysis is used to develop three ideas. First, the nondimensional parameters on which friction,F, and oil flow under the ring,Q, are identified. The variations ofFandQwith the nondimensional parameters are calculated. Second, it is shown that for normal wear on the second ring of a 2.6-L engine, there is a fivefold azimuthal variation inQ, suggesting that the azimuthal symmetry assumption must be relaxed, and that wear patterns must be taken into account in oil consumption calculations. Finally, a novel, gas-lubricated ring is described, and the variations inFandQwith nondimensional parameters calculated. Overall, it is found that the approach substantially simplifies the friction and oil consumption problem in reciprocating engines: for oil-lubricated rings,FandQvary with only four nondimensional parameters. For gas-lubricated rings,FandQvary with only three nondimensional parameters.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981606

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A pressure parameter method has been developed for the finite-element solution of Reynolds' equation. Finite-element solutions for bearings typically take a large amount of computer time to run. The pressure-parameter formation utilizing a new variable, which is equal to the pressure times a function of the film thickness raised to arbitrary power, can be applied to improve accuracy significantly. This is particularly true for large eccentricity ratios in journal bearings.

ISSN:0569-8197    

DOI:10.1080/05698198508981607

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A numerical solution to the problem of thermal elastotydrodynamic lubrication of line contacts was obtained by using a finite-difference formulation. The solution procedure consists of simultaneous solution of the thermal Reynolds equation, the elasticity equation, and the energy equation subject to appropriate boundary conditions. Pressure distribution, film shape, and temperature distribution were obtained for fully flooded conjunctions, a paraffinic lubricant, and various dimensionless speed parameters while the dimensionless load and materials parameters were held constant. Reduction in the minimum film thickness due to thermal effects (as a ratio of thermal to isothermal minimum film thickness) is given by a simple formula as a function of the thermal loading parameter, Q:Plots of pressure distribution, films shape, temperature distribution, and flow are shown for some representative cases.Presented at the 39th Annual Meeting in Chicago, Illinois May 7–10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981608

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A computer program is developed to analyze the contact of a rigid smooth plane and computer-simulated elastic rough surfaces. The simulated surfaces have isotropic Gaussian height distribution and bilinear autocorrelation function. Results of two cases are presented: (1) dry contact between a square elastic rough punch and a rigid smooth plane; (2) dry contact between an elastic rough half-space and a rigid smooth plane. Force-compliance relationship is compared with hat derived by Bush, Gibson, and Thomas. Real contact area ratio Aris found to be approximately proportional to nominal contact pressure in the range 0.025 < Ar< 0.3.Presented at the 39th Annual Meeting in Chicago, Illinois May 7—10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981609

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Electrical-contact-resistance and two-beam optical-interference techniques were employed to measure the real area of contact of magnetic tapes. The former technique does not work well due to significant contributions from tunnel effect and multimolecular insulating films; the latter provides shape and size distribution of asperity-contact areas.

ISSN:0569-8197    

DOI:10.1080/05698198508981610

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

An experimental program was conducted to evaluate the performance of a five-shoe tilting-pad journal bearing at low speeds and at different load conditions. Tests, including prolonged runs, were conducted in a speed range of 5–20 rpm, unit bearing load of 124 × 103N/m2(18 psi) to 206 × 104N/m2(300 psi).Presented at the 39th Annual Meeting in Chicago, Illinois, May 7—10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981611

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Experience has shown that the lubrication behavior of steel bearings can be significantly improved by a pretreatment called oil aging. Neat tricresyl phosphate (TCP) is normally used for this process (1)—(4). In this study, however, two hydrocarbon-type oils, each containing one percent TCP, were used for oil aging 52100 steel specimens under a variety of experimental conditions. Each coating formed as a result of the oil-aging process was analyzed by electron spectroscopy for chemical analysis (ESCA). The results indicate that microscale oxidation of the base oil and preferential adsorption phenomena within the oil system components are necessary for the formation of a desirable coating, including a phosphate type of material. The absence of aromatics and polar contaminants in the lubricant is also a determinant factor for the formation of a phosphate coating. The nature of this phosphate and the mechanism of its formation are explained.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981612

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Tricresyl phosphate (TCP) is an important extended-pressure additive in lubricating oils. Its depletion from reservoir oil could constitute a failure mechanism for bearing system. The interaction of TCP with bearing retainer and reservoir materials was investigated using an apparatus that mimicked centrifugal oil feed. TCP was not selectively absorbed by cotton-phenolic retainer or wool felt reservoir materials, but was absorbed by nitrile-acrylic and sintered nylon reservoir materials, which exhibited significant TCP retention. The results are discussed in terms of the degree of bulk oil absorption, the availability of polar sites on the sorbents, and the interaction between such sites and the TCP molecules.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981613

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper describes an experimental apparatus and procedure for measuring steady-state eccentricities in journal bearings. Eccentricity measurements for two five-pad tilting-pad bearings with load-on-pad and preloads of 0.0 and 0.2 are presented. Good agreement is shown between measured and theoretical eccentricities for a range of Sommerfeld numbers between 0.2 and 3.0. Relatively small deviations of the journal center from the load axis indicate negligible cross-coupling effects were present in the bearings.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981614

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The wear of ground-engaging tools in agriculture is affected by various soil properties, including the angularity of the abrasive particles in the soil. In an effort to quantitatively characterize the size and shape of these particles, a new technique has been used. The method is based on a Fourier analysis of the particle profiles. It yields a set of orientation invariant descriptors which quantify the size and shape of these profiles. This technique has been applied to various types of silica sand and crushed quartzite, as well as a few soil samples. The results obtained have shown that this analysis procedure can readily distinguish particles of differing angularities.

ISSN:0569-8197    

DOI:10.1080/05698198508981615

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor