上海交通大学：《Design and Manufacturing》课程教学资源（讲义）Lecture 9 CAM

国上我大峰 RDFD Cam Sophomore Design Simple Harmonic Motion Sin function has h continuous derivatives P= d_hx2πd a= de j= da -hn πd o0 ⑧Acceleration is discontinuous,jerk is infinite (Bad Cam Design) cam angle 0 ME371 Design Manufacturing ll 圆上泽夫大坐 RDFD Cam,Cycloidal Need to start with acceleration and integrate a=Csin π0 、B V- B2π0 since v=0 at 0=B, CB 2π -m] 2 0 B ME3 cam angle 0 16

16 ME371 Design & Manufacturing II RDFD Cam Sophomore Design Simple Harmonic Motion Sin function has continuous derivatives ∞ ∞ Acceleration is discontinuous, jerk is infinite (Bad Cam Design) h 2 2 3 3 1 cos 2 sin 2 cos 2 sin 2 h s - ds h v dθ dv h a d da h j d                                                       ME371 Design & Manufacturing II RDFD Cam, Cycloidal Need to start with acceleration and integrate 1 2 sin 2 cos 2 a C C v k                      1 2 2 2 2 1 cos 2 2 sin 2 2 C k C v C s C k                                          h since v=0 at 

国上清大峰 RDFD Cam,Cycloidal h S二 sin 2π /20+k B Since s=0 at 0=0,k2=0 Since s=h at 0=B CB B2 5=%0-5nm2aA) =-f9a) a-2%2% a%mA） 0 B ME3 cam angleθ 圈上活大峰 RDFD Cam,Cycloidal s=%-3rsm2a） Equation for a cycloid Cam has a cycloidal displacement or sinusoidal acceleration Valid cam design(follows fundamental law of cam design) a Acceleration and velocity are higher than other functions General procedure for design is to start with a continuous curve for acceleration and integrate. ME3 0 B cam angle A 17

17 ME371 Design & Manufacturing II RDFD Cam, Cycloidal • Since s=0 at =0, k2=0 • Since s=h at , 2 2 2 C h h C                                                                   2 cos 2 2 sin 2 2 1 cos 2 sin 2 3 2 2 h j h a h v h h s 2 2 2 sin 2 2 C sC k                     h ME371 Design & Manufacturing II RDFD Cam, Cycloidal Valid cam design (follows fundamental law of cam design) Acceleration and velocity are higher than other functions General procedure for design is to start with a continuous curve for acceleration and integrate.   2 sin 2 h h s        Equation for a cycloid. Cam has a cycloidal displacement or sinusoidal acceleration h