Viscoelastic machine elements elastomers and lubricants in machine systems

1995 ◽  
Vol 33 (2-3) ◽  
pp. 223
Author(s):  
Venelin Stoyanov Jivkov
Author(s):  
Kazuhiro Nakashima ◽  
Carlos Morillo ◽  
Yoshie Kurono ◽  
Yoshinori Sawae ◽  
Joichi Sugimura

PTFE is used as sealing material of machine elements in hydrogen utilizing machine systems, such as fuel cell vehicles and related infrastructures. It is necessary to know the tribological property of sealing materials in hydrogen gas to realize safety and reliability of machine elements operated in hydrogen environment. In this study, humidity in gases was focused on and its effects on the friction and wear of rubbing pair of PTFE pin and AISI 316L disk was investigated in pin-on-disk wear apparatus. The result indicated that the humidity in hydrogen gas had little effect on the friction coefficient between PTFE and AISI 316L. However, the specific wear rate of unfilled PTFE was clearly affected by the humidity. The amount of PTFE transfer film formed on the stainless surface gradually decreased with decreasing the humidity in hydrogen gas. The similar results could be obtained in inert argon gas as well. Water molecules remained in gaseous environments would be included in the formation process of PTFE transfer film affect on formation of PTFE transfer film. The humidity in hydrogen gas should be regulated to ensure the tribological behavior of the PTFE/stainless sliding pair being used in the hydrogen environment.


1979 ◽  
Vol 101 (2) ◽  
pp. 258-267 ◽  
Author(s):  
R. R. Allen

The kinematics of a gear power transmission may be characterized by a power-conserving kinematic transformation between independent and dependent angular velocities. The conjugate of this transform provides a relation between input and output torques. A bond graph multiport representing these kinematic relations provides a power-conserving core to which dissipative, inertial, and compliance effects may be added. This dynamic model of a power transmission may be connected with other machine elements (such as other kinematic mechanisms, motors, driveshafts, and loads) to form large-scale, computable dynamic models. Bond graph techniques are shown to facilitate the process of developing and assembling computable dynamic models for the study of gear trains as elements of machine systems. A numerical example is presented.


Author(s):  
Edward M. Connelly ◽  
Patricia A. Knoop ◽  
Francis J. Bourne ◽  
Diane G. Loental

2019 ◽  
Vol 7 (SI-TeMIC18) ◽  
Author(s):  
Norhanifah Abdul Rahman ◽  
Matzaini Katon Katon ◽  
Nurina Alya Zulkifli Zulkifli

Automatic Transmission (AT) system is efficient in the aspects of vehicle safety, comfort, reliability and driving performance. The objectives of this paper are to collect the oil samples from AT systems of engine bus according to manufacturer's recommendations and analyse collected oil samples using oil analysis technique. The sample transmission fluid which was taken from the AT gearbox has been experimentally analyzed. The oil samples were taken with an interval of 5,000km, 30,000km, 50,000km, 80,000km, 180,000km and 300,000km for AT bus operation. These samples then have been analyzed by comparing between new and used transmission fluid using Fourier Transform Infrared (FTIR) spectroscopy. Oil analysis by FTIR is a form of Predictive Maintenance (PdM) to avoid major failure in machine elements. Most machine elements are not easily accessible in the transmission system. Having a reliable technique would avoid the needs to open the components unnecessarily, hence, help to prevent catastrophic failure which are very costly, and ease of regular monitoring. In order to identify the major failures of automatic gearbox, forecasts can be made regarding the lube transmission fluid analysis test. By using this test, the minor problems can be determined before they become major failures. At the end of this research, the wear particles profile for interval mileage of AT system was obtained. Keywords: Wear, Automatic Transmission (AT), Transmission fluid, Fourier Transform Infrared (FTIR), Oil analysis.


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