Study And Computer Programming Of Steel Worm Gear Design

In common with worm transmission under high speed and high load,worm gear is always made of tin bronze and functions with alloy made worm.Although this meshing pair shows a good nicer antifriction erosion characteristic,some disadvantages are also obvious:the use of precious nonferrous metal leads to higher cost;lower service life;The contact and bending fatigue of bronze alloy are far lower than alloy steel,making worm gear a weakness in the transmission. Steel has many good mechanic properties as well as a low price.If we successfully apply steel to worm gear,we may save huge amounts of cost and decrease the size of transmission structure.What key problem we need to solve with steel worm gear is scuffing.Over the past years,Many experts have carried on the study of feasibility of steel worm gear.Numerous experiments have been made only to find that the use of extreme pressure additive helps to solve this problem. However,progress archieved of steel worm gear study is only limited to feasibility test and not even a design method has been put forward.This paper tries to give a such method.Research of this paper are mainly based on the data archieved by the FZG gear anti-scuffing test. We decide the proper positions and calculate the flash temperatures of both the FZG test gear and worm gear using the flash temperature method,as is one of the famous scuffing check model.Also we introduce a friction coefficient experience formula according to the lubricating oil and lubricating state of the worm gear.Then the allowable contact stress of the steel worm is deduced. A new design method is put out to tackle those too many unknown parameters in the deduced formulas.We also develop a VB-based steel worm gear design program,in which we use Access database technology together with Matlab interfaces to efficiently handle the problem of pictures and tables. All checking modules of this program are created with Matlab.The program has a succinct and clear interface and functions well.In this paper,we reduce the steel worm gear module to nearly3/4times that of the traditional worm gear,therefore the center distance of the steel worm gear transmission is reduced by1/5size of traditional one.Our design has archieved a good result.