摘要:

Specimens of materials used in dental couplings were tested in a simplified wear test machine which duplicated as closely as possible the actual wear conditions existing in operating couplings. The wear patterns that were obtained by tests of short duration on this machine duplicated those found in service. The results of tests covering the variables load, speed, duration, amplitude of reciprocating motion, surface finish and hardness are presented, together with brief discussions of the effects of these variables.Contributed by the ASLE Gear Symposium held in Chicago, January, 1959.

ISSN:0569-8197    

DOI:10.1080/05698195908972367

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

An experimental and analytical study has been undertaken to determine the lubrication environment of automotive hypoid gears under severe dynamic operating conditions. Results of an experimental investigation of gear loading and an analytical study of gear sliding under laboratory and field operating conditions in both automobiles and trucks are presented. The sliding relationships of four representative gears are discussed and the effects of changes in pinion offset and gear ratio on sliding velocity are studied. Increases in pinion offset and gear ratio both tend to increase the sliding velocity of hypoid gears. The present trends in automobile hypoid gear design are toward greater pinion offset and lower gear ratios. These two average trends are of opposite effect on gear sliding and tend to cancel each other. The sliding velocity of any particular gear set would have changed considerably in recent years if the design changes were primarily in one factor.Contributed by the ASLE Gear Symposium held in Chicago, January, 1959.

ISSN:0569-8197    

DOI:10.1080/05698195908972368

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

This paper discusses the effect of some lubricant variables and other relevant factors on gear tooth scuffing. Scuffing is defined as any form of scoring or abrasion of the tooth surface due to metal-to-metal contact. The scuff-limited load is defined as the tooth load at which an arbitrary amount of the working tooth area is scuffed. The factors considered include lubricant bulk viscosity, lubricant type and deterioration, test gear and test machine variables, gear speed, the location and rate of lubricant supply, lubricant supply temperature, and the presence of inert gas atmospheres. The results are compared with, and examined in the light of, other published data.Contributed by the ASLE Technical Committee on Gears and Gear Lubrication and presented at the ASLE Gear Symposium held in Chicago, January, 1959.Presented at the ASLE Gear Lubrication Symposium, Chicago, Illinois, January 26 and 27, 1959.

ISSN:0569-8197    

DOI:10.1080/05698195908972369

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

The mechanism of boundary friction is assumed here to be due to the molecular forces between hydrocarbon molecules adsorbed on the surfaces rather than to welding and tearing of the opposing surface roughness. On this assumption the frictional force, which arises when two orientated layers are moved over each other, can be calculated. The formulae for the Van der Waals and the repulsion forces are those successfully used by Müller for paraffins. The different values of the kinetic and static frictions can be explained by the forces being due to the tails of the chains in kinetic and the sides of the chains in static lubrication.

ISSN:0569-8197    

DOI:10.1080/05698195908972370

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

A radioactive tracer, sulfur-35, synthesized into zinc dialkyl dithiophosphate molecules, was used to study the EP film formed on cast iron cams and tappets run in motor oils containing this additive. The sulfur content of static films increased with immersion time and temperature, and the presence of phosphate-coated metal surfaces. The bound sulfur of films formed during dynamic tests increased with running time, load, and with the use of phosphate-coated surfaces. These conditions also influenced the ratio of Zn:P:S contained in both static and dynamic films. Zinc, and particularly phosphorus, in the films increased more rapidly than the sulfur with increased temperature and/or pressure. The dynamic films are not easily worn off by running in nonadditive oil. The mechanism of action of zinc dithiophosphates appears to be related to chemical reactions of additive decomposition products with the metal surfaces to form tightly-bound solid films which reduce damage under extreme pressure conditions. Radioactive counting and X-ray spectroscopy were used to obtain the amount of sulfur and zinc on tappets. Densitometer traces of the autoradiographs were utilized to determine the distribution of the sulfur on cam and tappet surfaces.Contributed by the ASLE Technical Committee on Lubrication Fundamentals and presented at the Annual Meeting of the American Society of Lubrication Engineers held in Buffalo, New York, April, 1959.

ISSN:0569-8197    

DOI:10.1080/05698195908972371

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

The viscosity of motor oils at low temperatures strongly affects the cranking speed of the motor. In a previous paper the author has shown that the viscosity characteristics of motor oils at low temperatures may be unusual, especially when they contain Viscosity Index Improvers.

ISSN:0569-8197    

DOI:10.1080/05698195908972372

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

The friction and wear behavior of selected solid lubricants and wear specimens has been studied in a modified four-ball wear machine. Data were obtained at1000 Ffor sliding speeds of120and700 ftperminunder initial Hertzian contact stresses of about250,000 psi. Conventional solid lubricant material ssuch as lead oxide (litharge), molybdenum disulfide, and graphite were evaluated. A new dry solid lubricant, metal-free phthalocyanine, was studied and was usually found to have superior lubricating ability. Wear specimens of AISI Type M-1 tool steel and titanium carbide-nickel-molybdenum cermet showed the most promise for high-temperature sliding systems. Initial coefficients of friction less than0.1were obtained with combinations of these materials.Contributed by the ASLE Technical Committee on Lubrication Fundamentals and presented at the Annual Meeting of the American Society of Lubrication Engineers held in Buffalo, New York, April, 1959.

ISSN:0569-8197    

DOI:10.1080/05698195908972373

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

A study has been made of the various solid and liquid lubricants which could be considered for use to temperatures above540 C. This study consisted of a literature survey to isolate temperature-stable, low shear strength compounds, and some experimental work to evaluate the most promising materials. Many of these compounds were effective at high temperatures and the results can explain the compatibility of certain metals at high temperatures. These compounds were not effective at lower temperatures. A more detailed study was made of the sliding characteristics of metals when lubricated with silver and molten boric oxide. The results show that, for silver, a number of factors such as choice of bearing materials, strength, and impurities affect the frictional behavior. Boric oxide, under conditions of boundary lubrication, showed a large increase in friction when the viscosity increased above2400poise. Variations in the friction could be explained by independent variations of viscosity and shear area.

ISSN:0569-8197    

DOI:10.1080/05698195908972374

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

Heat transfer data from recent studies of rotating cylinders are utilized in the the heat balance method of predicting oil film temperatures for shaft and plain bearing combinations. Good agreement is obtained between calculated temperatures and experimental values. It is shown that the heat which is dissipated from a rotating shaft may be much greater than that from a stationary shaft and from the bearing housings, and it may be the major path for heat dissipation in certain cases.Contributed by the ASLE Technical Committee on Lubrication Fundamentals and presented at the Annual Meeting of the American Society of Lubrication Engineers held in Cleveland, Ohio, April, 1958.

ISSN:0569-8197    

DOI:10.1080/05698195908972375

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

An exact solution is found for the finite fitted journal bearing. Numerical calculations are carried out for an arc of 60° and an arc of 120° for various positions of the bearing. A comparison is made of the load, pressure distribution, and friction force for the finite bearing and the infinite bearing (no side flow). It is concluded that in general the neglect of side flow yields a solution that may be in great error.Contributed by the ASLE Technical Committee on Bearings and Bearings Lubrication and presented at the Annual Meeting of the American Society of Lubrication Engineers held in Buffalo, N.Y., April, 1959.This work was supported in part by the Office of Ordnance Research, U.S. Army.

ISSN:0569-8197    

DOI:10.1080/05698195908972376

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor