The Thermal Analysis Of Epicyclic Gear Reducer Based On Thermal Network Method

With moving axes, inner and outer meshing, several epicyclic gears to support load, the epicyclic gear reducer has been widely used as an accelerator or reducer device compared to the fixed axis gear reducer, for it has abundant advantages in transmission. However, the transmission reliability and efficiency of epicyclic gear reducer is considerably influenced by its limited space and small radiating areas. As a result, analyzing the temperature distribution and variation for the transmission designing of epicyclic gear reducer during its work is increasingly important.This thesis has mainly focused on the following fields. Detailedly analyses the relative movement and stress of gears and bearings in the epicyclic gear reducer, lists the computational formulas of load and kinematic velocity for meshing points on the gears, illustrates the contact force and relative kinematic velocity between rolling elements and ferrules, in order to make it as the foundation of heat origin research in the epicyclic gear reducer. By researching the friction pair in epicyclic gear reducer, establishes the models of heat current power for friction pair according to the loss of frictional power, judges the relative merits and choices the applications. At the same time, sets up the models for windage loss, churning loss and heat generation of shaft joint in high speed rotational accessories. Establishes the computational models for heat transfer coefficient in the surface of accessory based on the theory of heat transfer, including the one between surface of gears and fuel-air mixture,plus inner and outer circles or rolling elements with oil or fuel-air mixture. On this basis, analyses the heating relationship among accessories in the epicyclic gear reducer, and establishes the thermal network model for heat transfer in the reducer, uses MATLAB language to write interactive interface and computational program for thermal network, gives the rules of distribution and variety for stable and transient state of epicyclic gear reducer. Builds a platform for the transmission of reducer, gets temperature of some key nodes by collecting the datas of epicyclic gear reducer in practical work, compares the two results of theory and experiment, and finds coherence, through which, proves the validity of theoretical analysis and computation model.