Theoretical and experimental investigation of the characteristics of two phase transmission clutches

ABSTRACT PhD: Thesis THEORETICAL AND EXPERIMENTAL INVESTIGATION OF THE CHARACTERISTICS OF TWO PHASE TRANSMISSION CLUTCHES Ismail TÜRKBAY Fırat University Institute of Science and Technology Mechanical Education Department 2001,Page:101 Centrifugal clutches run with two principle: either centrifugal forces or frictional forces. Friction force and torque increase in proportion to the rotation speed. In another word centrifugal clutches allow motor to run without subjecting to initial loading and large torques. Centrifugal clutches, addditonally, make the counter torque or load smoother and works as a safety clutches in excessive loading conditions. A centrifugal clutches runs depending on rotation speed. During torque transmission the frictioning parts work. The frictioning parts are in the form of ring, ball, particule or roll. The magnitude of the torque can be adjusted by changing the mass of the frictioning parts. One of the common disadvantages of the centrifugal clutches is the friction wear between the friction elements and the drum in case of starting made or break down, due to continuous running. This cause a decrease in the life of friction elements, or the whole centrifugal clutche. In this study, an electric motor, a V belt-pulley mechanism, a ball-centrifugal clutches and a dynamometer were used to perform the experiments. Ball-centrifugal clutches was loaded by breaking the dynamometer, with a slide rheostat and helezonic resistance. The measurement were done with tachogenerator, plotter and tachometer etc.VI In the study a new type ball-centrifugal clutche was designed and produced in Technical Education Faculty of Firat University. The balls in diffrent diameters (4,6 and 8 mm) were used as ruction element. In the experiment, the effect of ball-centrifugal clutches emptiness factor, porosity and rotation speed on the torque transfer were determined. For this aim the torque transmitted by the ball-centrifugal clutche was measured by changing emptiness factor and ball diameter for different rotation speeds. The torque transmitted increased with the emptiness factor, the speed and the decrease in ball diameter for the same speed. With constant emptiness factors, porosity was determined to decrease with the smaller ball-diameter. The torque transmitted by the inner and side surfaces of the drum were calculated theoretically and compared with the experimental ones. It was seen that there were not big differences in the results. As a last experiment gear oil was added to the ball-centrifugal clutches as a second phase load transmitter. Consequently it was determined that frictional wear and temperature decreased considerably and starting period longed. But the torque- transmission capacity decreased slightly.