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1、参考机械原理（第八版） 孙恒 陈作模 高等教育出版社个人资料，仅限交流使用，侵权必究IntroductionThis book mainly talk about some Basic theory of machinery. On the whole (总体上)about how to analyze a mechanism in construction 结构学，kinematics 运动学，Dynamics 动力学. And then talk about the basic knowledge of some common mechanism and the analysis, lik
2、e linkage mechanism, gear mechanismMachinery 机械=machine 机器 + mechanism 机构（注意名次区分，不用讲）Link 构件 motion element（单元体）in mechanismPart 零件manufacture element in machineStructure Analysis of mechanismKinematic pair 运动副1. Definition：A kinematic pair is a connection between two bodies that imposes constraints
3、 施加约束 on their relative movement 相对运动.2. Classification:Lower pairs(contact with surfaces) Revolute pairs (转动副);Prismatic pairs (移动副)Higher pairs(contact with points and lines)Planar kinematic pair 平面运动副； spatial kinematic pair 空间运动副3. DOF(the degree of freedom 自由度) ：the number of independent moveme
4、nts it has.(按下面例子用坐标系画图解释)DOF of a rigid body in a plane = 3 (2 translating motion & 1 rotating motion).DOF of a rigid body in space = 6 (3 translating motion & 3 rotating motion)Mechanism1. Including：fixed link 机架,driving link 原动件，drived link 从动件.2. How can a mechanism get the Determined motion 确定的
5、运动？F(the DOF) = the number of driving linkMotion Analysis of Mechanism1. known conditions:Machine dimensions（尺寸） ，pattern of motion of driving linkpattern of motion of drived link(Displacement 位移, velocity, acceleration)2. Instantaneous(瞬时的 ) center of velocity 速度瞬心（见机械原理 P39）：Definition：Coincidence
6、 point 重合点; Instantaneous speed 瞬时速度 is equal；Two mechanism that have relative movement Classification：Absolute Instantaneous center of velocity 绝对瞬心（absolute velocity is zero）Relative Instantaneous center of velocity 相对顺心Force Analysis of Mechanism1. The force on the machinery:1) Driving force 驱动力2
7、) Resistance 阻抗力:effective resistance(like: the gravity 重力 of Weight in a lift)；detrimental resistance（like: Friction）2. Inertial force 惯性力：substitution method of masses 质量代换法，substitutional point 代换点（具体方法见机械原理课本 P57）3. the friction in kinematic pair：1) Prismatic pairs: equivalent coefficient of fri
8、ction 当量摩擦因数 fv ; total reaction总反力 FR；angle of friction 摩擦角（重点看课本 P59P60 例题）2) Revolute pairs ：circle of friction 摩擦圆（看课本 p61）Mechanical efficiency and balance 平衡Mechanical efficiency 效率Formula：课本 p75p76 公式Series 串联 and Parallel 并联(课本 p77p78 画顺序图解释)Self locking 自锁Definition：because of friction，cant
9、 move no matter how much force.Condition:(课本 p79 公式，画受力图讲解)Balance of rotor（转子）(联系课程“机械系统动力学 mechanical system dynamics”)Type：（用公式和画图表示，课本 p86p88）static Balance of rotor 转子静平衡 Inertial force 惯性力（和为零）dynamic Balance of rotor 转子动平衡 Inertial force ,Inertial moment 惯性力矩（和均为零）purpose：The unbalance will c
10、ause the vibration 振动, reduce the mechanical efficiency and the service life? 7-4Linkage mechanism（以 planar four-bar linkage（平面四杆机构）为主）1. Structure（用曲柄摇杆机构画图解释）1) Fixed link 机架the link is fixed and cant move2) Coupler 连杆the link that dont connect to the fixed link3) Side link 连架杆the two link that co
11、nnect to the fixed link, including crank(曲柄 can rotate a turn) and rocker(摇杆 can just swing in a certain range)4) Revolute pairRevolute pair of revolving motion 周转副 and Revolute pair of swing motion 摆转副2. Type(画图举例解释，见课本 P125128)1) Crank-rocker mechanism 曲柄摇杆机构 2) Double-crank mechanism 双曲柄机构 the wh
12、eel of train3) Double-rocker mechanism 双摇杆机构 the structure of crane 起重机the three basic types can evolve 演化 to many other structure：4) Slider-crank mechanism 曲柄滑块机构 widely used in machine tool 机床3. Some basic knowledge：1) How can A be revolute pair of revolving motion？(画图解释，图 8-21 见课本p131)杆 a + d = c
13、 + d; a order d is min(进一步推演出 3 种基本杆 成立的条件)2) Extreme Position 极位( 图见课本 p132)Premise 前提： is Crank-rocker mechanism；the crank is the driving link.The position of mechanism when the CD is in C1D and C2D3) Dead point 死点(图见课本 p135,与极位对比看)：Premise 前提： is Crank-rocker mechanism；the rocker is the driving l
14、ink.The position of mechanism when the CD is in C1D and C2D，and the link AB cant move in this position，Application：Folding table 折叠桌（p135 图）Solution: use inertia 惯性Cam mechanism1. Definition: A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion i
15、nto linear motion or linear motion into rotary motion.2. Structure: cam(driving link) ,follower(推杆 drived link),camshaft 凸轮轴(Inverse cam mechanism 反凸轮机构 the cam is drived link)3. Advantage: Get the expected movement law, Simple structure4. Disadvantage: the contact in higher pairs，Easy to wear；the M
16、anufacture is difficult5. Type：(画图解释，图见 P168)*plate cam 盘形凸轮the most commonly used cam，Planar mechanism，the cam rotate around the camshaft 凸轮轴，the follower does a linear Reciprocation(直线往复运动)cylindrical cam 圆柱凸轮 spatial mechanism,the cam is a cylinder with an irregular shape, the follower does a linear Reciprocation.6. other tips1) base circle 基圆the smallest circle with the minimum radius of cam profile凸轮轮廓2) (根据凸轮速度瞬心，联系一下上
