摘要:

AbstractOne of the most interesting problems in traction drives is the analysis of their power transmission efficiency. Using an experimental two‐disk machine and two planetary traction drives, together with fourteen test oils, it is shown that the power transmission efficiency can increase up to 97% in the case of an experimental planetary traction drive. The synthetic traction oils bring about a lower efficiency than mineral oils when the output torque is small. This is ascribed to their higher traction coefficients which cause larger friction in the rolling bearings which support the rolling element

ISSN:0265-6582    

DOI:10.1002/jsl.3000090102

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThree experiments were conducted to evaluate the long‐term running performance in vacuo of ball bearings lubricated by a synthetic oil and grease. The first experiment was carried out using ball bearings of a shielded deep‐groove type (no. 6204) filled with a grease containing perfluoropolyalkylether (PFPAE) as a base oil and TFE as a thickener. Tests were done at room temperature in a vacuum of 10−4∼10−5Pa mainly at a rotational speed of 2,000 r/min under an axial load of 50N. The bearings were successfully run for a period of 24,400 h, which corresponds to 3 × 109revolutions. About 10% in weight of the grease was lost during the test. An inspection of the running accuracy of the bearings tested showed negligible change. The degradation of the grease inspected by FTIR was found to be negligible. A change in the molecular weight distribution of the grease was not observed during the test. The second experiment was conducted with angular‐contact‐type ball bearings (no. 7204), with retainers impregnated with PFPAE oils. Exploratory work was done using full‐component‐type ball bearings (no. 7204), lubricated by a heat‐cured PFPAE oils, both in vacuo and in an air environment. The bearings were run for 280 h (5.0 × 106revolutions) in air at a speed of 300 r/min under an axial load of 50 N, but failed to operate afer 25 h (4.5 × 105re

ISSN:0265-6582    

DOI:10.1002/jsl.3000090103

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAn approximate formula is presented for the maximum traction coefficient in EHD conditions, by making some reasonable simplifications of an Eyring fluid model. Experiments are conducted for some mineral and synthetic hydrocarbon oils over a wide range of temperatures. Among the rheological parameters related to maximum traction, the representative stress τ0, is determined from the experimental traction curve while the effective viscosity‐pressure coefficient α is obtained in a high pressure viscometer. When the temperature is raised, α falls and τ0rises. The behaviour of τ0for some paraffinic oils follows the Eyring theory while the effect of the dissociation of molecular clusters appears with the naphthenic oils. The increase in temperature causes a reduction in the maximum traction coefficient, which can be predicted with sufficient accuracy by the formula using the rheological parameters expressed as a function of tempe

ISSN:0265-6582    

DOI:10.1002/jsl.3000090104

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAn interesting characteristic of abrasion is the dependence of the wear rate on the particle size of the abrasive grits used to lubricate the abrasive papers. Three types of polymers, PTFE, PA, PI, several of their composites, and three metals were selected for studying the effect of particle size on wear rate. The pins were abraded against Sic abrasive papers of various mesh sizes under constant loading in multi‐pass conditions. For some of the polymers and their composites (PA and PEI) the size effect on wear rate was similar to that for the metals. Beyond a critical particle size, no increase in wear was found with increasing particle size. On the other hand, PTFE, PI, and their composites showed the opposite effect. SEM and EDAX were used to investigate the related mechanism

ISSN:0265-6582    

DOI:10.1002/jsl.3000090105

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000090106

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000090107

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000090108

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000090101

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY