Determination of Hydrodynamic Power Losses in a Gearing

Abstract

Despite the relatively numerous experimental studies, there are few published works on the topic of development of mathematical models that describe the hydrodynamic processes in gears. There is no generic analytical model that integrates all types of losses. The purpose of this work is to develop a modern generalised methodology for calculating the hydrodynamic power losses of high-speed gears. For each gear, partially or fully immersed into an oil bath, the power spent to overcome the hydromechanical resistance can be represented as the sum of the following: the Coriolis force moment arising from the radial movement of the oil in the tooth spaces of the rotating gear, the viscous friction forces moment on the periphery of the gear addendums in the oil bath and the viscous friction forces moment at the face of the gear in the oil bath. The hydrodynamic power losses due to the Coriolis force action, viscosity friction losses at the periphery of the gear and the viscosity friction at the face of the gear (both turbulent and laminar modes) were observed separately. From the mathematical simulation of the rotation processes when the gear is immersed into the oil bath, an analytical dependence was obtained. It allows predicting the influence of the geometrical parameters of the gearing on the hydrodynamic power losses. Analysis of the calculation results of the power losses due to the action of hydraulic resistance forces and results from experimental studies is provided for several gears with different hydromechanical parameters. The proposed method of calculating power loss due to hydromechanical resistance of the oil bath to the rotation of the gear gave results that were close to the experimental data. Acceptable coincidence of theoretical and experimental results allows recommending the received analytical dependencies for practical calculations of high-speed gears.

Determination of Power Losses Due to Periodic Compression-Expansion of the Oil-Air Mixture Between the Teeth of Gears. Part 1. Mathematical Model

“…Також, [10,11] були проведені вичерпні дослідження різних видів розподілу втрат потужності. Крім того автори [12] дослідили узагальнену методику розрахунку гідродинамічних втрат потужності у високошвидкісних зубчастих передачах та проаналізували втрати потужності внаслідок тертя ковзання і кочення в зубчастому зачепленні [13]. За допомогою CFD (обчислювальної гідродинаміки) та експериментальних вимірювань автори [14,15] дослідили втрати на перемішування в планетарних редукторах.…”