Abstract
Some hydraulic actuators operate periodically. The periodic motion led to pulsating pressure in a hose. Pulsating pressure in the hoses led to problems with reliability of hoses and fittings. When there is high pressure oscillation in the hose, the whole hose arrangement vibrates and strains structure of the hose. If the moving hose touches somewhere the friction of abrasion warms the hose. On the other hand the hose bloats periodically all the time because of the pressure oscillation. When the hose bloats deformation of the rubber and the hose structure rises temperature. There are longitudinal and radial motions between hose linings and hose reinforcements so the friction rises temperature of the hose. The static pressure loss and the oscillation of the hose increase the temperature of the hose.
This paper concentrates to study how pressure oscillation and the hose bloating rise temperature of the hoses. The examinee hoses were measured by three different measurement ways. By means of a servo valve the pressure oscillation was produced to the examinee hoses. The all hoses (steel pipe, thermoplastic hose, heavy-duty with 2 reinforcement and extra heavy-duty with 3 reinforcement) were measured in the same time. The warming effect of abrasion was studied by help of a thermograph camera. The main result was that the warming was caused by the abrasion of the moving hoses.
