toothedgearing概要.ppt

第三章 Toothed gearing 齿轮传动 §3-1 General considerations 概述 §3-2 Materials, types of failure and design criteria 齿轮材料、失效形式和计算准则 §3-3 Loads in cylindrical gearing 圆柱齿轮传动载荷计算 §3-4 Strength of spur cylindrical gearing 直齿圆柱齿轮传动强度计算 §3-5 Strength of helical cylindrical gearing 斜齿圆柱齿轮传动强度计算 Toothed gearing design example 齿轮传动设计实例 §3-6 Straight bevel gearing 直齿圆锥齿轮传动 Problems 思考题 §3-1 General considerations 概述 Characteristics and applications 特点和应用 Types of the toothed gearing 齿轮分类 一、Characteristics and applications 特点和应用 1、 Advantages 优点 ① Long service life and high reliability 工作可靠，寿命长 ②Constant speed ratio 传动比恒定 ③ High efficiency 工作效率高 ④Small overall size 结构紧凑 3、Applications 应用 二、 Types of toothed gearing齿轮分类 1、 According to the difference between the relative positions of the shafts： 按轴布置方式分 ① Toothed gearing between parallel shafts 平行轴齿轮传动 （ Cylindrical gearing圆柱齿轮传动 ） §3-2 Materials, types of failures and design criteria of gears 齿轮材料、失效形式和计算准则 ? Materials of gears 齿轮材料 ?Types of failures 失效形式 ? Design criteria 计算准则 ⑵ Critical gears 重要应用： Processing procedure 工艺过程： Cutting teeth 切齿 Hardening 淬火 Grinding 磨削 2、 Cast steel铸钢 （For gears of large diameters 尺寸较大、不容易锻造时选用 da≥400mm） 三、Design criteria 计算准则 1、 Close gearing闭式齿轮传动： The principal types of failure are pitting, tooth breakage and seizing of the teeth. And seizing of the teeth occurs under heavy load and calculation in checking for the possibility of tooth seizure is not effective. Hence, only calculations of the contacting fatigue strength and bending fatigue strength are carried out.以点蚀、轮齿折断和胶合失效形式为主，其中胶合发生于重载，而且计算方法不成熟，所以一般只进行齿面接触疲劳强度和齿根弯曲疲劳强度计算。 §3-3 Loads in cylindrical gearing圆柱齿轮传动载荷计算 一、 Forces in spur cylindrical gearing直齿圆柱齿轮传动受力分析 Exer