2005 年 2005 巻 6 号 p. 120-125
Recently an oil-hydraulic system has been compact and high-pressurized and that causes the steep rise of the system temperature because of the small heat volume. When the system temperature has risen so much, characteristics of the working oil deteriorate and the system will be dangerous fmally.
It is very important to study a simple and precise way to predict the temperature rise of the system. The lost power rises the system temperature. Bondgraph method is convenient to predict power loss because the method is based on the concept of power transmission. Consequently, the Bondgraph method is very available to predict the system temperature rise of oil-hydraulic systems.
The oil-flow dynamics with the heat generation mechanism was modeled one-dimensionally using ordinary differential equations by Bondgraph method, which is very convenient for modeling and simulation of heat generation. On the other hand, the heat transfer in the housing was analyzed three-dimensionally using the partial differential equation of heat conduction. The prediction of the temperature distributions were calculated effectively by coupling these two kinds of equation systems. In the present paper, this prediction method is applied to a real oil-hydraulic system. The simulation result was compared with the experimental results and they agreed very well.