This paper presents the mult-goal optimal design of the two-grade helical cylindrical gear retarder.

Numerical simulation of helical gear warm closed-die forging;

In order to meet the operating requirement, the precision design and machining for the helical gear are made.

Numerical simulation of cylindrical bevel gear cold forging with shape similarity method;

The paper introduces a kind of way to survey single-adapted cylindrical bevel gear.

The choose and design of the traditional cylindrical bevel gear need to check the book date in great quantities.

Simple method of precise measurement for single-adapted helical cylindrical gear;

When hobbing helical cylindrical gear which has a smaller or bigger spiral angle,a relatively small or big gear ratio is gotten by using common differential calculating formula of hobbing helical cylindrical gear.

The simple method of the precise measurement to single-adapted helical cylindrical gear was presented.

Coincidence coefficient of helical gear transimission;

A method of precision forging process for helical gear is developed according to the structure of movable die,in which the upper punch and the die with teeth move down at the same time.