第八章 链传动幻灯片.pptVIP

第八章 Chain drives 链传动 §8－1 General considerations 概述 §8－2 Motion features of chain drives 链传动的运动特性 §8－3 Design of roller chain drive 套筒滚子链设计计算 §8－4 Forces in chain drive 链传动受力分析 §8－5 Replacement and tension of chain drive 链传动的布置与张紧 §8-1 General considerations 概述 Characteristics and applications 特点和应用 Types of chain drives 链传动分类 一、 Characteristics and applications特点和应用 3、 Applications 应用 （ For low speed and severe operation condition 适用于低速，胜任恶劣工况） 三、 Roller chains 套筒滚子链 §8－2 Motion features of chain drives 链传动的运动特性 Variation in speed ratio 运动不均匀性 Dynamic load 动载荷 ③ 2、 Instantaneous speed ratio 瞬时传动比 ① ② 二、 Dynamic load 动载荷 2、Periodic change V′周期性变化→Cross vibration 横向振动 →Dynamic load 动载荷 §8－3 Roller chain drive design  套筒滚子链设计计算 一、Principal parameters 参数选择 3、P（ pitch节距） It is best practice to elect a chain with the minimum allowable pitch for the given load 节距P 尽量小，但排数≤3～4（均匀） ⑵Lp（链条长度用链节数表示）L＝LpP 二、 Types of failure 失效形式 三、Limit power curve and allowable power curve 极限功率曲线和许用功率曲线 6－Wear breakage limit under poor lubrication and severe operating condition 润滑不良、工作环境恶劣的磨损极限 四、 Design 设计计算 1、The power which can be transmitted by a chain drive under actual working conditions is determined by multiplying the tabular value by the correction factors 实际工作中与上述试验条件不同时， 对工作功率P和许用功率P0进行修正： §8-4 Forces in the chain drives 链传动受力分析 §8－5 Tension and arrangement of  the chain drive  链传动的布置与张紧 二、 Tension 张紧 1、Useful load 工作拉力 F1＝1000P/V 2、Centrifugal tension 离心拉力 F2＝qV2 3、Weight tension 垂度拉力F3＝ Kfqga For a horizontal drive 水平传动 ：Kf＝6 For an angle of inclination of the drive to the horizontal up to 400 倾角40°：Kf ＝4 For over 400 倾角40°：Kf ＝2 For a