Key, spline and pin joints §3 键、花键和销联接 Key, spline and pin joints §3-1 键联接 Key joints §3-2 花键联接 Spline joints §3-3 销联接 Pin 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

一、分类 Types of the key joints Ordinary straight key joints Straight key joints Guiding and sliding straight key joints Loose joints Woodruff key joints Key joints Taper key joints Tight joints Taper key Tangent double-taper key joints

普通平键联接 Ordinary straight key joints Rounded end Square end One rounded and one square end

导向平键和滑键 Guiding and sliding straight key

3. 半圆键 Woodruff key

4. 楔键联接 Taper key joint

5. 切向键联接 Tangent double-taper key joint

二、平键联接的尺寸选择和强度计算 Selection of sizes and strength calculations for straight key joints 1、失效形式Types of failure ⑴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）

⑵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 weakest among the key, shaft and hub. And it usually occurs on the hub.

2. 计算公式 Calculations

3. 平键联接的计算步骤 Design procedure for straight key joints BACK

§3-2 花键联接 Spline joints 依靠轴和毂上齿的互压传递转矩，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. 花键联接的特点 Features of spline joints 花键联接的分类 Types of spline joints

Features of spline joints 一、花键联接的特点 Features of spline joints With respect to straight key joints: Uniform force distribution Less stress concentration More accurately centered Teeth 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 Major diameter fit Minor diameter fit Fit on sides of spline 矩形花键定心方式

Major diameter fit Side fit 渐开线花键定心方式 BACK

§3-3 销联接 Pin joints 销联接的功用 Functions of pin joints 销的分类 Types of pin joints

一、销联接的功用 Functions 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

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）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 ）

（3）特殊形式销 Special types of pin ① 孔未开通或拆卸困难时： 螺尾锥销 With thread for disassembly ②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

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