机械原理第六章动平衡.pptx

第六章 机械的平衡;1. Purposes;The balance of component rotating about a fixed axis Rotor(转子): Parts constrained to rotate about a fixed axis. ;rigid rotor;1. Phenomena of static imbalance ;2. Geometric condition ;3. Theory of static balancing;;;resolution： A. Graphical method;B. Analytical method　 mx1 rx1 + mx2 rx2 + mx3 rx3 + mxP rxP = 0 my1 ry1 + my2 ry2 + my3 ry3 + myP ryP = 0 ;EXAMPLE;Solution: Resolve the position vectors into xy components : R1=1.135m θ1=113.4°; R1x=-0.451,R1y=-1.042 R2=0.822m θ2=48.8 °; R2x=+0.541,R2y=0.618 Solve equations mbRbx=-m1R1x-m2R2x=-(1.2)(-0.451)-(1.8)(0.541)=-0.433 mbRby=-m1R1y-m2R2y=-(1.21.042)-(1.8)(0.618-2.363 Solve equations ;Solution: The mass-radius product can be obtained with a variety of shapes. When Rb=0.806m at required angle of 259.6 °,the mass for this counterweight design is then: mb=2.042kg.m/0.806m=2.980kg at the chosen radius of Rb=0.806m ;§6-3 Calculation for the dynamic balancing of a rigid rotor刚性回转体的动平衡;;;;平衡原理： 将集中质量点所产生的离心力F向两个平衡基面上分解，得到两个分力F1和F2 ； 合力F 对系统的影响可以完全有两分力F1 、 F2对系统的影响所代替；;;;;;1. Static Balancing Experiment 静平衡实验;静平衡试验台;2.Dynamic Balancing Experiment动平衡实验;;§ 6-5 Balancing of planar mechanisms ;1.Entire balancing of mechanism ;2.Partial balancing of mechanism ;本章结束;9、春去春又回，新桃换旧符。在那桃花盛开的地方，在这醉人芬芳的季节，愿你生活像春天一样阳光，心情像桃花一样美丽，日子像桃子一样甜蜜。11月-2011月-20Sunday, November 22, 2020 10、人的志向通常和他们的能力成正比例。20:15:2120:15:2120:1511/22/2020 8:15:21 PM 11、夫学须志也，才须学也，非学无以广才，非志无以成学。11月-2020:15:2120:15Nov-2022-Nov-20 12、越是无能的人，越喜欢挑剔别人的错儿。20:15:2120:15:2120:15Sunday, November 22, 2020 13、志不立，天下无可成之事。11月-2011月-2020:15:2120:15:21November 22, 2020 14、Thank you very much for taking me with you on that splendid outing to London. It was the first time that I had seen the Tower or any of the other famous sights. If Id gone alone, I couldnt have seen nearly as much, because I wouldnt have known my way about. 。22 十一月 20208:15:21 下午20:15:21