摘要:

A combination if electron photo micrographs and sensitive friction measurements indicate that the dry friction if glass may be due to surface melting under frictional heat. Stick slip phenomena are examined and the characteristic “tear drop” scratch is seen to be composed if a widening track if fused cracks ending in a “circular spot” if fused glass. Low temperatures or lubrication prevent this. For short durations at low loads, temperatures, and sliding speeds, most lubricants gave the same friction and wear results. When conditions become more severe or time more extended, various classes if lubricant excellence can be found. Wear measurements following “run in” indicate that with proper lubricants and operating conditions glass bearing surfaces can be operated at high loads and high temperatures.Presented at the 24th ASLE Annual Meeting in Philadelphia, May 5–9, 1969.

ISSN:0569-8197    

DOI:10.1080/05698196908972266

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

This work determined what effect stiffness in the direction normal to the plane of contact between surfaces in sliding contact had on the phenomenon of stick-slip.

ISSN:0569-8197    

DOI:10.1080/05698196908972267

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Wear and friction properties of three representative neopentyl polyol esters, together with the common diester lubricant base, bis(2-ethylhexyl) sebacate, were studied with the four-ball wear machine at 266 F and 5–50 kg load in the presence and in the absence if tricresyl phosphate. The rubbing surfaces were 52100 steel, 440 C stainless steel and M-50 steel. With 52100 low-chromium steel balls, wear rates were largely independent of ester type. Percolated tricresyl phosphate reduced wear moderately at low loads only. Stainless steel 440 C and M-50 steel gave results significantly different from those with 52100 steel at all loads. In the case of the stainless steel wear was greatly increased at a load of 50 kg and tricresyl phosphate (1%) was ineffective at all loads. M-50 steel gave the lowest wear rates. It showed no response to tricresyl phosphate. Average friction coefficients of all the steels showed little change with the variables examined except for a small increase with load and for slightly lower values with M-50 steel.Presented at the 24th ASLE Annual Meeting in Philadelphia, May 5–9, 1969.

ISSN:0569-8197    

DOI:10.1080/05698196908972268

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

ISSN:0569-8197    

DOI:10.1080/05698196908972269

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A simple apparatus has been developed to measure frictional forces of small magnitude. It provides a continuous recording of tangential forces ranging from below 0.01 dyne to about 50 dynes. Details of the stick-slip characteristics are thereby recorded. The small normal forces required are applied and controlled by passing a current through a meter movement. The basic element for sensing frictional forces is a d'Arsonval galvanometer system. The frictional force applied to a lever arm produces a torque about the axis of the galvanometer system. A dual photodiode-servo amplifier system provides a correcting current to the galvanometer so that the mechanically imposed torque is automatically balanced. The correcting current is directly proportional to the tangential force. This apparatus has been extensively used in friction studies of individual textile fibers and for fine wire samples. It has also been used for measurements of stylus friction on flat surfaces under small loads. This paper includes a detailed description of the apparatus and illustrations of its application.Presented at the 24th ASLE Annual Meeting in Philadelphia, May 5–9, 19691Supported in part by U. S. Dept. of Agriculture SURDD Grant No. 12-14-100-7661(72).

ISSN:0569-8197    

DOI:10.1080/05698196908972270

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A technique is described which has been found useful for understanding the role played by molecular structure in the viscosity of liquid polyisobutylene polymers. A linear logarithmic relation, between the viscosity and the average molecular weight of low molecular weight polyisobutylenes, is demonstrated. This relationship is used to indicate an apparent difference in the molecular structures of some polyisobutylenes.

ISSN:0569-8197    

DOI:10.1080/05698196908972271

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Because of the increasing use of the neopentyl polyol esters as lubricants, an analytical method capable of giving detailed information concerning the composition of these complex ester mixtures is desirable. Methods of gas-liquid chromatography and thin-layer chromatography have been applied in the successful development if such an analytical method. By direct programmed temperature gas chromatography of the lubricants, the components are separated according to volatility; in most cases resolution is adequate for semi-quantitative analysis. Gas-liquid chromatographic analysis of the free acids produced by hydrolysis of the sample reveals the acyl composition. The parent polyols are determined by programmed temperature gas chromatography of their valerate esters. A semi-preparative thin-layer chromatographic method permits the isolation of the three main ester types, trimethylol propane, pentaerythritol, and dipentaerythritol, for further analysis. A combination of these analytical methods permits a detailed study of the changes in composition which occur in these lubricants during service.Presented at the 24th ASLE Annual Meeting in Philadelphia, May 5–9, 1969.

ISSN:0569-8197    

DOI:10.1080/05698196908972272

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Neopentyl polyol esters, typical of turbine engine lubricant base stocks, are thermally stable at 500 F, unless, as reported by others, ferrous metals are present; in the latter case oil degradation and metal corrosion are severe. Tricresyl phosphate (TCP) stabilizes the metal-ester system by generating a passive oxide film on the active metal surface.

ISSN:0569-8197    

DOI:10.1080/05698196908972273

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The load capacity and power loss of spiral groove bearings, lubricated with a Newtonian, incompressible liquid with a viscosity depending on temperature only, are determined by solving the continuity and momentum equations analytically and the energy equation for the grooves and ridges numerically. It is assumed that the total flow perpendicular to the relative velocity of the bearing parts is zero. This implies that the generated heat is discharged by conduction to the bearing parts only. The effect of the “thermal entrance region” is investigated.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Houston, Texas, October 14–16, 1969

ISSN:0569-8197    

DOI:10.1080/05698196908972274

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor