key, spline and pin joints

1、12 键、花键和销联接Key, spline and pin joints12-1 键联接 Key joints12-2 花键联接 Spline joints12-3 销联接 Pin joints12-4 其它联接 Other joints 12-1 键联接 Key joints 分类 Types of the key joints平键联接的尺寸选择和强度计算Option of sizes and strength calculations for straight key joints* Selection of sizes and strength & Calculations f

2、or straight key joints一、分类 Types of the key jointsKey jointsLoose jointsTight jointsStraight key jointsWoodruff key jointsOrdinary straight key jointsGuiding and sliding straight key jointsTaper keyTaper key jointsTangent double-taper key joints1. 普通平键联接Ordinary straight key joints平键的两侧面是工作面，靠键和键槽之间

3、的互压传递转矩。The load is carried by the sides of straight keys. The both side surfaces of key and keyway press each other, through which the torque is transmitted.Rounded end Square endOne rounded and one square end2. 导向平键和滑键Guiding and sliding straight key3. 半圆键 Woodruff key4. 楔键联接 Taper key joint楔键联接上下

4、面为工作面，靠键、轴和毂之间的摩擦力以及键受到的偏压传递扭矩。Torque is transmitted by friction of above and below surfaces on the key, shaft and hub.5. 切向键联接 Tangent double-taper key joint 切向键的工作面是两个楔键组成矩形的窄面，工作面上的挤压力沿轴的切线方向，靠挤压传递扭矩。Tangent double-taper key joint comprises two taper keys. The tow taper keys compose a rectangle a

5、nd the small face of the rectangle is its operating surface. Torque is transmitted by the pressure between the operating surfaces of the key , shaft and hub. 失效形式Types of failure主要失效形式 The main types of failure：工作面压溃Crushing（静联接 Fixed joints）工作面磨损 Wear（动联接 Sliding joints）二、平键联接的尺寸选择和强度计算Selection of

6、 sizes and strength calculations for straight key jointsv有时：键剪断shear failure of the key（一般不作计算，重要时验算 No such strength calculations are required in designing.） 工作面的压溃或磨损发生在键、轴和毂三者中较弱的零件上，一般为毂。Crushing or wear of the operating surfaces usually take place on the elements of which the strength is weakes

7、t among the key, shaft and hub. And it usually occurs on the hub.2. 计算公式 Calculations假设压力在键的接触长度范围内分布均匀，则根据挤压强度或耐磨性的条件性计算It is assumed that the pressure is uniformly distributed over the surfaces of contact between the sides of the key and the hub and the shaft. Then the strength conditions to resis

8、t crushing and wear respectively are：Allowable pressing stressAllowable pressureContact length of keyHeight of keyContact height of key and hub3. 平键联接的计算步骤 Design procedure for straight key joints 花键联接的特点 Features of spline joints 花键联接的分类 Types of spline joints 12-2 花键联接 Spline joints依靠轴和毂上齿的互压传递转矩，

9、可用于动联接和静联接。The teeth of shaft and hub press each other, through which the torque is transmitted. The spline joints can be used for both fixed and sliding joints. 一、花键联接的特点 Features of spline jointsWith respect to straight key joints:Uniform force distributionLess stress concentrationMore accurately

10、centeredTeeth are difficult to be manufactured二、花键联接的分类 Types of spline joints（矩形花键 Rectangle spline、渐开线花键Involute spline 、三角形花键Triangle spline ）三、花键的定心方式Centering methods of spline 矩形花键定心方式Major diameter fit Minor diameter fit Fit on sides of spline渐开线花键定心方式Major diameter fit Side fit12-3 销联接 Pin j

11、oints 销联接的功用 Functions of pin joints 销的分类 Types of pin joints（1）定位 Locating （2）安全装置 Safety device （3）传递不大的载荷 Transmit relatively small loads一、销联接的功用 Functions of pin joints二、销的分类 Types of pin（1）普通圆柱销 Plain cylindrical pins （多次装拆，定位精度下降 Locating precision is lowered after disassembled many times） （2）

12、普通圆锥销 Plain taper pins （锥度1：50 、自锁、可以多次装拆 With a taper of 1:50,selflocking, may be disassembled for many times ）v（3）特殊形式销 Special types of pin v 孔未开通或拆卸困难时： 螺尾锥销 With thread for disassemblyv 冲击、振动或变载荷时： 开尾锥销、槽销或弹性圆柱销（防松） With open slot for fastening 12-4 其它联接 Other joints 成形联接 Shaped joints 过盈联接Interference fit joints 焊接 Welded joints一、成形联接 Shaped join