机械设计基础第8传动

第八章带传动§8-1§8-4V1§8-1

23§8-1

4QQNj QNjF=fN

F=2fN= =

Q=f jf= j

j2)56表表8-1V带截面尺寸和单位长度质量（摘自GB11544-YDE7简图绳芯，楔角为40，角为40，相对高度8简图抗拉体为绳芯，楔角为60的9F1 FF2

Fe=

=F1P=

(kW)fiFe

n

(NF1-F0=F0-F=1(F+F

F=F+

Fe=

-

=

- dN=Fsindq+(F+dF)sin 切向:fdNFcosdq(FdFcosdq

2a 12dN=FdqfdN=dF12

dF=fdqF1

=

lnF1=fa

aFaF F+

F=Fef F=Fef

efa-

=2(FF-F=

minefa ec

=20

min1+1ef(1)初拉力F0↑→Fec↑

F+ QQNj①QNj =fN=

=2fN=

Q=f ffvsinj

j>

j ( F= (三)s»E

s1=F1/s2=F2/dbddsc=

smax =s1+sb1+scl=FEA

l1=EA

A2F2A2F2F1v2<v<v1e=v1-v2v2=-

e=~v=

v=

i=n1

»

Fec=F1(1

e

efva

smaxs1+sb1+sc£[s s1£[s-sb1-scF(1-1

sA(1-1

-s)(1-1)P=Fecv=

=

表8-4a单根普通V带的基本额定功率PoZABC-补充表1单根窄V带的基本额定功率Po—————特定条件:包角a1=180 实际条件:单根V带所能传递功率?r=(0+DP0)Kai„1

ZABC.27

补充表2单根窄V带额定功率的增量DP0表8-5包角修正系数1YZABCDYZABCDE 表8-7工作情况系数软起动根据Pca、2.YZABCDE③dd2=i

v=

Y20,20.4,25,28,31.5,35.5,40,45,50,56,63,71,80,90,100,112,Z50,56,63,71,75,80,90,100,112,125,132,140,150,160,180,224,250,280,315,355,400,500,A75,80,85,90,95,100,106,112,118,125,132,140,150,160,180,224,250,280,315,355,400,450,500,560,630,710,B125,132,140,150,160,170,180,200,224,250,280,315,355,400,500,560,600,630,710,750,800,900,1000,C200,212,224,236,250,265,280,300,315,335,355,400,450,500,600,630,710,750,800,900,1000,1120,1250,1400,1600,D355,375,400,425,450,475,500,560,600,630,710,750,800,900,1060,1120,1250,1400,1500,1600,1800,E500,530,560,600,630,710,750,800,900,1000,1120,1250,1400,1600,1800,2000,2240,2.0.7(dd1+dd2)<a0<

BBDaDaL=2AB++AθC »AθC »d0+p2+-0=2acosq+2q)d2+(p-2q) ) a»a»0+Ld-Ld2

d d 2q»sinq=dd2-YZABCDYZABCDEAB2.AB1a1

-dd2-a

·57.3z=Pca= (P0+DP)KaKL 0

a=p-1-1+qv1

a =2zFsin Pca=KAP=1.1·4=4.4v=

=p·90·1440=6.78˛(5~25)(m/s)

dd2=idd1=3.4·90= 2．选取普通V带带型3．确定带轮基准直根据0.7(dd1＋dd2＜a0＜2dd1＋dd2，初步确定中心距a0=500mm。2 =2a+p2

+ +dd2

d

=2·500+2

315

59024·500

=1661a=

+Ld-

=

=4702 ．确定带轮基准直径a=180-dd2-dd1·57.3=180-315-90·57.3=152> 由n1=1440r/min、dd1=90mm、i=3.4，查表8-4a和表8-4b得z 0Ka

=4

=

F

=50