JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS
Online ISSN : 2189-9967
Print ISSN : 0915-1168
ISSN-L : 0915-1168
Volume 60 , Issue 5
Special Issue on Lubrication Life of Greases for Rolling Bearings
Showing 1-14 articles out of 14 articles from the selected issue
Announcement
Contents
Serial Messages to Tribologists
Special Issue on Lubrication Life of Greases for Rolling Bearings
Explanation
Explanation
Original Contribution
  • ―Experimental Study―
    Yuichiro TOKUNAGA, Joichi SUGIMURA, Yuji YAMAMOTO
    2015 Volume 60 Issue 5 Pages 332-341
    Published: May 15, 2015
    Released: April 15, 2017
    JOURNALS FREE ACCESS

    A series of experiments were carried out to verify the sealing and lubricating performance of the surface structure for mechanical seals with the functions of the low-friction, the low-leakage, and also the pumping effect. The thrust bearing structures were formed in the higher pressure side as a lubricating mechanism, and the reversed thrust bearing structures were formed in the lower pressure side as a sealing mechanism in the mechanical seals’ surfaces. The fluid film thickness and the friction coefficient were measured and compared with the numerical calculation results of our previous report. Cavitation regions formed in the sliding surface were observed with the direct observation system of mechanical seals. Furthermore, the magnitude of the cavitation pressure was also discussed. The experimental results indicated that the theoretical results discussed in our previous report were proved to be valid. Thus we conclude that the novel sealing and lubricating mechanisms for mechanical seals with the functions of the low-friction, the low-leakage and the pumping effect can be technically feasible.

    Download PDF (1981K)
Short Paper
  • Kazuo TAGAWA, Masayoshi MURAKI
    2015 Volume 60 Issue 5 Pages 342-348
    Published: May 15, 2015
    Released: April 15, 2017
    JOURNALS FREE ACCESS

    Friction properties of the oils containing polyalkylmethacrylate with different alkyl group were studied in relation to adsorption and desorption ability of polymers. First, the coefficient of friction with a pendulum type tester were roughly correlated with a magnitude of frequency shift ΔF obtained using a quartz crystal microbalance with dissipation tester, in which ΔF was related to adsorption ability of polymers onto a metal surface. This suggests that the friction under the mild contact conditions is governed by surface coverage capacity of polymers. On the other hand, tribological properties under the severer conditions with a steel ball-on-steel disk type tester were evaluated under a temperature of 100°C, a mean Hertzian pressure of 0.73 GPa and a mean rolling speed of 0.05 m/s and a slide/roll ratio of 50%. Among the polymers, a mixed alkyl group containing methyl group was superior to the other polymers in terms of stability in friction with time, friction reducing effect and antiwear properties. It is inferred that the friction under the severe conditions was influenced by surface coverage capacity of polymers as well as adsorption preservation capability, which was evaluated as a separation degree during the tribotest.

    Download PDF (1023K)
Report of the Society
feedback
Top