上海交通大学：《Design and Manufacturing》课程教学资源（讲义）Lecture11 gear train

上济充道大峰 A BNO TONG LN时 Types of Gear trains N2 out NIN NAN5 Om Simple Gear Trains N3 Na Ns N6 N2Om N4 N6 ® Maximum gear ratio of 1:10 based on size constraints Gear ratios cancel each other out ® Useful for changing direction 6 N6 Could change direction with belt 上海充通大粤 Types of Gear trains Compound Gear Trains ©More than1 gear on a shaft ©Allows for larger N Output shaft gear train ratios .YZiW“g▣ * N.V77777W777777N, -Q shaft N

6 Simple Gear Trains Maximum gear ratio of 1:10 based on size constraints Gear ratios cancel each other out Useful for changing direction Could change direction with belt in out in ω N N ω N N N N N N N N ω 6 2 6 5 5 4 4 3 3 2   Types of Gear trains Compound Gear Trains More than 1 gear on a shaft Allows for larger gear train ratios 2 4 3 5 out in N N ω ω N N             Types of Gear trains

上海充通大学 Types of Gear trains Compound Train Design 2 是) @ou N If N2=N,and N3=Ns 3 Reduction ratio out →品) 5 Will be used to determine the no.of stages given a reduction ratio 2 stages 上海充通大粤 Types of Gear trains Compound Train Design Design train with gear ratio of 180:1 ·Two stages have ratio√8o-l3.4164 too large Three stages has ratio 180=5.646 →贷)=56 ·At14 teeth Pinion Teeth ratio Gear teeth actual ratio is 9 12 5.646 67.7546 =179.6789 13 5.646 73.4008 OK for power 14 5.646 79.0470 transmission; not for phasing 15 5.646 84.6932 16 5.646 90.3395

7 Compound Train Design ωin ωout 2 3 4 5 2 4 3 5 in out N N ω ω N N           If N2=N4 and N3=N5 2 2 3 in out N ω ω N        2 3 2 in out ω N ω N        Reduction ratio 2 stages Will be used to determine the no. of stages given a reduction ratio Types of Gear trains • Design train with gear ratio of 180:1 • Two stages have ratio too large • Three stages has ratio • At 14 teeth actual ratio is • OK for power transmission; not for phasing 180 13.4164 180 5.646 3  Pinion Teeth * ratio Gear teeth 12 5.646 67.7546 13 5.646 73.4008 14 5.646 79.0470 15 5.646 84.6932 16 5.646 90.3395 179.6789 14 79 3        3 3 2 180 5.646 N N         Compound Train Design Types of Gear trains

上海充通大学 Types of Gear trains Compound Train Design:Exact GR Factor desired ratio: 180=22x32x5 XXZZZZZZZZ7Z Want to keep each ratio ii的 品 NXXXXXXXZZZ77ZZ about the same (i.e. 6x6x5) ©14x6=84 114t h14t8 ©14x5=70 ©Total ratio, We could have used: 70 84 =180 180=2x90=2x2x45=2x2x5x9=4x5x9 14 or 4.5x6x(20/3)etc. 上海充通大粤 Types of Gear trains Reverted Compound Train Input and output shafts are aligned For reverted gear trains: R2+R3=R4+R5 Commercial three stage reverted compound train D2+D3=D4+D5 N2+N3=N4+N5 ©Gear ratio is N2N4 @Din N3 Ns

8 Compound Train Design: Exact GR Factor desired ratio: 180=22x32x5 Want to keep each ratio about the same (i.e. 6x6x5) 14x6=84 14x5=70 Total ratio 180 14 84 14 70 2              We could have used: 180=2x90=2x2x45=2x2x5x9=4x5x9 or 4.5x6x(20/3) etc. Types of Gear trains Reverted Compound Train Input and output shafts are aligned For reverted gear trains: R2+R3=R4+R5 D2+D3=D4+D5 N2+N3=N4+N5 Gear ratio is Commercial three stage reverted compound train 5 4 3 2 N N N N ω ω in out  Types of Gear trains