摘要:

Hydrodynamic journal bearing stability tests were conducted with 3.8 centimeter (1.5 in) diameter tilted-lobe bearings. The bearings had 3, 5, and 7 lobes and L/D ratios from 0.2 to 1.0. They were tested in water and MIL-L-7808G oil at 294 K (70 F) at speeds to 5, 400 rpm with zero load. Stability was not appreciably affected by the number of lobes and decreased with a decrease in L/D ratio. However, a three-tilted-lobe bearing with an offset factor of 0. 76 and an L/D of 0.5 was more stable than a three-centrally-lobed bearing with an offset factor of 0.50 and an L/D of 1.0. All data can be presented in terms of the parameter[Mbar](Γ*)1.4= 9, where[Mbar]is the dimensionless mass parameter and Γ* is the optimized stability parameter.Presented at the 31st Annual Meeting in Philadelphia, Pennsylvania, May 10–13, 1976

ISSN:0569-8197    

DOI:10.1080/05698197708982843

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The relative oxidative attack at the various carbon-hydrogen bonds of the model ester lubricant neopentyl hexanoate at temperatures 150–200 C was determined by GLC analysis of appropriate derivatives. Relative rates for single carbon-hydrogen bonds were: primary I,“normal” secondary 15, alpha-acyl secondary 2, and alpha-alcohol secondary 4. These results may furnish valuable insight in the development of more oxidatively stable esters for use in high-temperature jet engine lubricants.Presented at the 31st Annual Meeting in Philadelphia, Pennsylvania, May 10–13, 1976

ISSN:0569-8197    

DOI:10.1080/05698197708982844

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A new impeller-to-sump seal was developed for a line of hermetically sealed centrifugal compressor units. Tests, using an actual compressor unit, were made to simulate steady operating conditions. Both new seal configurations and the original seal were tested. A new seal configuration resulted in a 25:1 reduction in refrigerant leakage. The seal met all other technical and economic requirements dictated by the application.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Boston, Massachusetts, October 5–7, 1976

ISSN:0569-8197    

DOI:10.1080/05698197708982845

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Presented at the 31st Annual Meeting in Philadelphia, Pennsylvania, May 10–13, 1976

ISSN:0569-8197    

DOI:10.1080/05698197708982846

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Timken OK load tests along with friction and wear measurements for a series of gear oils containing sulfurized olefin (SO) and oleyl amine salt of acid 2-ethylhexylphosphate (AP) have been carried out. Electron probe microanalyses have been made on the worn surfaces of Timken test blocks lubricated with the gear-oils. The main results are as follows:

ISSN:0569-8197    

DOI:10.1080/05698197708982847

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Results of experimental work in which plain bearings of various materials were operated under oscillatory motion and heavy loads are described. Bearing stress (based on projected area) covered the range 69 MN/m2to 620 MN/m2. The effect of different grease lubricants, temperature, bearing stress, and oscillatory mode on wear and friction characteristics was studied. Maximum load capacity of a number of bronze and steel bearing materials has been determined. Recommendations for selection of materials and design of bearings for oscillatory motion and heavy loads are given along with design charts and tables.Presented at the 31st Annual Meeting in Philadelphia, Pennsylvania, May 10–13, 1976

ISSN:0569-8197    

DOI:10.1080/05698197708982848

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

An apparatus has been constructed for studying exoelectron emission from steel bearing balls which have been run in a Barwell four-ball surface fatigue wear tester. The test ball is periodically removed from the tester, cleaned to remove its oil film, transferred to a vacuum chamber, and illuminated by ultraviolet light. The emitted exoelectrons originating at new surface area generated on the ball during fatigue testing are detected by an electron multiplier. By rotating the ball and measuring the exoelectron emission as a function of position, the source or sources of the emission can be localized. The resolution of the research apparatus is presently limited to 0.27 mm, the width of the scanning spot. Exoelectron emission decay results indicate a relatively slow drop in emission with time. Preliminary results indicate that the fatigue failure occurs at one of several sites which have given enhanced electron emission.Presented at the 31st Annual Meeting in Philadelphia, Pennsylvania, May 10–13, 1976

ISSN:0569-8197    

DOI:10.1080/05698197708982849

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

An experimental study, supplemented by a thermal analysis, has been made to determine the frictional behavior, wear rates, and temperature rise of grease-lubricated sand-cast CDA 932 bronze bearings running against mild steel shafts under boundary lubricated conditions. The results showed that when the bearings were operating effectively, the wear factors,“K”, were essentially constant over a wide range of loads and speeds. Good correlation was obtained between the experimental bearing temperature measurements and the analytical predictions of the bearing temperature rise as a result of frictional heating. If the bearing temperatures exceeded 150 C (300 F), extremely high wear rates were obtained. At low speeds and high loads, there was often a transition region above which the wear rates and frictional characteristics of the bearing decreased to very low values. This transition appeared to be the result of the formation of some type of protective film.Presented at the 31st Annual Meeting in Philadelphia, Pennsylvania, May 10–13, 1976

ISSN:0569-8197    

DOI:10.1080/05698197708982850

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Exoelectron emission has been observed from a clean, annealed Mg (0001) surface during oxygen and chlorine adsorption at pressures of 6.5×10−5N/m2and lower. The studies were performed in an ultrahigh vacuum system. The crystals were cleaned by argon ion bombardment and annealed, at 300 C. Auger electron spectroscopy was used to verify cleanliness, and low energy electron diffraction was used to verify that the surface was annealed. The emission was found to be oxygen arrival rate dependent. Two peaks were observed in the electron emission with exposure. Evidence is presented that the formation of the second peak corresponds to oxidation of the Mg surface. No emission was observed from clean aluminum during adsorption. The results verify that electron emission occurs from a strain free surface simply upon adsorption of oxygen. A qualitative explanation for the mechanisms of emission in terms of chemical effects is presented.Presented at the 31st Annual Meeting in Philadelphia, Pennsylvania, May 10–13, 1976

ISSN:0569-8197    

DOI:10.1080/05698197708982851

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Specially built hemispherical grinding wheel segments have been used to evaluate four grinding lubricants in a modified pin-on-disk wear test. These results are compared to external cylindrical grinding tests of the same lubricants. The scanning electron microscope and electron microprobe are used to show the similarity in wear morphologies for the two different tests. It is suggested that the hemisphere pin-on-disk test may provide a useful tool for grinding lubricant development.Presented at the 31st Annual Meeting in Philadelphia, Pennsylvania, May 10–13, 1976

ISSN:0569-8197    

DOI:10.1080/05698197708982852

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor