Study On Through-flow Characteristics Inside A Rotary Oil Gallery Of Lubrication System In Planetary Transmission

The lubrication system is an important component of planetary transmission, it is very important for assuring the reliability and service life of the planetary transmission mechanism. Especially for the demand of working at high power and overloading conditions, the lubrication of planetary transmission mechanism turns to be more crucial. The lubrication system mainly consists of rotary oil gallery. The oil is rotating at a high speed with the rotary oil gallery, both shear force and centrifugal force are functioned on it. Thus, for a fixed oil supply pressure, the oil flow rate would be different for various rotational speeds. In order to achieve the precise lubrication of parts within the planetary transmission, it is necessary to understand the through-flow characteristics of the oil flows inside a rotary oil gallery of lubrication system in planetary transmission and the influence of various parameters on the flow field. In this paper, the oil flow characteristics and the influence of various parameters on the flow field were researched aim to the request of accurate lubrication of key components in planetary transmission.Firstly, the three-dimensional flow field model of rotary oil gallery was established, and introduced sliding mesh to describe rotation basin, and achieved the oil flow characteristics. Lubricants in the hole will be formed the frontal are and the back area. The flow velocity of oil in the frontal area is small, and in the back area is large. The oil is mainly concentrated in the back area in the first half, and the oil is mainly found in the frontal area in the second half. a special rotating oil flow characteristics testing device of the rotary oil gallery is built, and the correctness of numerical calculation is verified by test. Then, the numerical model is extended to establish the numerical model of the rotary oil gallery with import and export.On the basis of the numerical flow model of the rotary oil gallery in the lubrication system of planetary transmission, the flow state in the oil distribution mechanism of the rotary oil gallery is analyzed, and the theoretical model is established. The root causes of the flow decreases is analyzed. Then, the theoretical model is extended to establish the theoretical model of the rotary oil gallery with import and export. Based on MATLAB/GUI software, the software named "lubricating oil distribution forecast at high speed " is designed and developed.On the basis of three-dimensional flow field model, the paper analyzed the influence of various parameters on the through-flow characteristics inside the oil distribution mechanism of the rotary oil gallery, especially the effects of speed, supply pressure, oil viscosity, aperture, hole number and angles on the through-flow characteristics inside the oil distribution mechanism. Speed increases, oil flow velocity decreases, holes in the frontal area expanded, the back area is narrow, turbulent kinetic energy decreases on average, turbulent Eddy-dissipation rate weakened, and the oil flow decreases. Oil supply pressure and temperature increases will lead to increased flow. Number of holes, hole diameters, and angles increase can also cause increased flow. While, the outer diameter increases will lower the flow rate. The research of the influence of parameters on through-flow characteristics inside the oil distribution mechanism of the rotary oil gallery provides a reference to the accurate lubrication of planetary transmission at high speed.