The Study of High Speed Rolling Friction : 2nd Report, On the General Characteristics

Succeeding to the 1st report of us, the effects of several factors on the rolling friction which are rolling speed, load, surface roughness, material of rolling element, amount and viscosity of lubricating oil and dust in oil have been investigated experimentally in order to research fundamentally the characteristics of the rolling friction at high speed. It has been clarified that the rolling friction at high speed differs considerably from that at low speed which is well known by previous studies. The important results for high speed rolling friction obtained by this experiments are as follows : The rolling friction of the dry surface increases according to the increase of rolling speed and load in which the effect of speed is superior. In this case, the coefficient of rolling friction on the dry surface may be estimated as 2∼5×10-4. Under the condition of the surface lubricated with oil the coefficient of rolling friction becomes the order of 10-8 that is larger than that of dry surface. Then, the main part of the rolling friction may be considered to be due to the fluid friction of lubricating oil.