Abstract
The structure that oil is supplied from the center of a shaft to gear face through a hole machined at gear bottomland is widely used in forced lubrication type gearbox. The hole is sometimes used for supplying oil from the gear face to a needle roller bearing located at the center of the gear in bath lubrication. In this case, the oil flow is opposite to centrifugal force and thus, it becomes complex. This phenomenon is important because it affects to the lubrication of the bearing. The purpose of the study is to clarify the oil flow qualitatively and quantitatively. In this paper, the flow pattern is visualized using acrylic gear as a first step of the study. The flow pattern is changed by hole diameter and gear rotation speed.
