đồ án máy trộn bê tông "hộp giảm tốc 1 cấp"

7/30/2019 n my trn b tng "hp gim tc 1 cp"

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n thit kmy GVHD: V Nh Thnh

SVTH: Nguyn Ngc nh trang 1

n c sai


2/46



Li ni u

Mn hc thit k my ng vai tr quan trng trong

chng trnh o to k s v cn b k thut v cu to

,nguyn l lm vic v phng php tnh ton thit k cc chi

tit, cc thit b phc v cho cc my mc ngnh cng nghip,

nng nghip, giao thng vn ti. ..

n mn hc thit k my c s kt hp cht ch

gia l thuyt vi thc nghim. L thuyt tnh ton cc chi

tit my c xy dng trn c s nhng kin thc v ton

hc, vt l, c hc l thuyt, nguyn l my, sc bn vt

liu ; c xc minh v hon thin qua th nghim v thc

tin sn xut.

n mn hc thit k my l mt trong cc n c

tm quan trng nht i vi mt sinh vin khoa c kh. n

gip cho sinh vin hiu nhng kin thc c bn v cu to,

nguyn l lm vic v phng php tnh ton thit k cc chi

tit c cng dng chung ,nhm bi dng cho sinh vin kh

nng gii quyt nhng vn tnh ton v thit k cc chi

tit my ,lm c s vn dng vo vic thit k my.

c s gip v hng dn tn tnh ca thy V Nh

Thnh m n nay n mn hc ca em hon thnh. Tuy nhin

vic thit k n khng trnh khi sai st em rt mong c

s ch bo ca cc thy v s ch bo ca cc bn.

Em xin chn thnh cm n thy V Nh Thnh gip em

hon thnh cng vic c giao.


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ChngI : Gii thiu chung v my trn b tng v my trn b tng t do hnh nnct di ng

1.1Cng dng v phn loi:

Cng dng:

My trn btng dng trn u cc thnh phn vt liu: ct, , ximng, cht ph giav nc to nn hn hp btng. Trn b tng bng my m bo c cht lng b

tng, cho nng sut cao v tit kim xi mng.

Phn loi:

Da vo phng php trn, my trn btng c chia lm 2 loi: my trn t do v my

trn cng bc.

Da vo phng php d liu ( btng ra khi thng trn), my trn btng c cc loi:

- My trn d liu bng cch lt p thng.

- My trn d liu bng mng.

- My trn d liu bng cch nghing thng.

- My trn d liu bng cch quay ngc thng so vi chiu quay khi trn.

- My trn d liu bng cch m y thng. Phng php ny ch c t hit k cho my

trn cng bc.

Da vo tnh lin tc, chia 2 loi: my trn chu k v my trn lin tc. Da vo tnh c

ng, chia 2 loi: my trn c nh v my trn c lp. My trn c nh c lp trong

cc dy chuyn sn xut btng v ti cc xng c cc cu kin btng. My trn c lp

thng c s dng ti cc cng trng xy dng.


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1.2 GII THIU MY TRN BTNG T DO HNH QU TO DI NG

Trong phm vi n ny, em xin chn my trn b tng, vi thng trn dng qu to,

khng c gu tip liu, kt cu thng trn n gin, c cu truyn ng n gin, gn nh

, d s dng trong cng vic nho trn b tng v thao tc lt b tng phc v trong xy

dng nh dn dng, d ch to

.

Hnh 1.1 : My trn b tng hnh nn ct dng qu to khng c gu tip liu.

1- Khung my; 2- Thng trn; 3- V lng quay gi lt thng; 4- Hp gim tc; 5- B truynai; 6- ng c in; 7- a ng v thng trn; 8- Bn p ko thanh di a nh v thngtrn; 9- Bnh rng nn; 10- Vnh rng quanh thng trn; 11- Gi lt thng trn; 12 Trcv quay.

+Nguyn l hot ng: trn vt liu th thng trn nghing mt gc 45oso vi phng nm ngang.

ng c in (6) quay, truyn chuyn ng qua b truyn ai v hp gim tc lm bnhrng nn (9) quay, ko theo vnh rng gn vo thng trn (10) quay, lm cho vt liu trong thng trn c nho trn.

Khi x hn hp b tng rakhi thng trn th trc ht p bn p (8) ko thanh gi rakhi a nh v, ri quay v lng (3), nh chuyn ng ca cp bnh rng n khp trong,gi lt (11) quay, lm thng trn p xung vt liu trn ra ngoi. Khi th thngtrn quay mt gc 135oso vi phng thng ng.

+ u im :

Loi ny c cu to n gin, tiu hao nng lng t, c dng nhiu nhng cht lng btng cha tht tt thng dng trn b tng nng, b tng ct liu ln, di chuyn ddng, khng i hi ngi s dng c trnh cao, ch to gn nh, vt liu ch to khngcao, s dng rng ri.

+ Nhc im :


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i hi ngi cng nhn phi vt liu trc tip vo thng trn, vi kt cu ming thngtrn cao nn ngi cng nhn phi mt nhiu cng sc v thigian ht vt liu vothng trn, cung cp vt liu b tng xy dng nh cao tng nng sut thp, i hi phi lintc, tui bn s dng khng cao, nn ch dng cho cc loi my trn dung tch nh.

Chng 2: TNH TON U VO

Theo ta c Vhh=Vthng =1000 l m Vhh =(22,5)Vsx, Chn Vsx= 500

2.1TNH KCH THC THNG TRN

Vi thng trn hnh nn ct ta c t s: L/D = 18.0

Vi : L:l chiu di thng trn

D: ng knh thng trn .

cho qu trnh tnh ton c d

dng ta chia thng trn thnh 2 phn(hv):

- Phn hnh tr c th tch 1V

- Phn hnh nn ct c th l V2

thit k :

+ V2= 0.8 1V

Hnh 2.1 S thng trn


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+ Chiu cao ca phn hnh tr bng ng sinh ca nn

ct

Gi: + chiu cao ca nn ct l h2

+ bn knh nh ca nn ct l r

+ bn knh ln ca nn ct l R ,suy ra R-r =

a.

Gi s: a=0.6 h2 L= 0.9D= 1.8R.

Ta c:

V1+V2= Vthung (1)

h1+ h2=L=1.8R (2)

V2= 0.8V1 (3)

a2 + h22 = h1

2 (4)

a=0.6h2 (5)

V1= 3.14R2.h1 (6)

V2= h2.3.14.(R2+r2+R.r)/3 (7)

Gii h 7 phng trnh trn ta thu c:

r=5.2838dm

R=5,673 dm

h1=5,4975 dm

h2=4,714 dm

Nh vy ta s thit k thng trn c kch thc nh sau

- Chiu di thng trn : L = 10,2114 dm


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- ng knh thng trn : D = 11,346 dm

- ng knh ming thng : d = 2r=10,5676 dm

2.2. TNH TON NG LC HC V NNG SUTCHO THIT B :

2.2.1. TNH TON NNG SUT :

Nng sut s dng ca my trn b tng

tgbsd KmVN .. [m3/h].

Trong :

Vb - dung tch khi b tong trn c ca m trn, m3

Vb = Vsx .f

Vsx : dung tch sn xut ca thng trn, m3

Vsx = 0.5 m3

f : h s xut liu

f =0.66

Vb = 0.33 m3

ms m trn trong 1 gi.

Ktgh s s dng thi gian : Ktg = 0,8-0,9

Chn . Ktg = 0.8

+ S m trn trong 1 gi tnh bng cng thc :

Tm

3600 .

Trong :

T = t1 + t2 + t3, Vi : t1thi gian vt liu vo thng. (s)

t2thi gian trn (s).

t3thi gian b tng ra (s).

Tra bng 14.1 ( my xy dng )

Vi my trn c Vsx = 500l .


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t1=17 s

t2=90 s

t3=25 s

T= 132 s

27132

3600m .

Nsd = 7.2 m3/h

Nng sut mi ca ca my trn : Nca = Nsd.tca

vi tca = 8 h

+ Nng sut mi ca ca my trn 500 l.

Nca = 7.2 8 = 57.6 m3/ca.

2.2.2. TNH TON C BN CHO MY TRN B TNG T DO :

Cng sut ng c dn ng quay cho thng trn.

Phn ln nng lng truyn ng cho my trn t do b tn hao cho vic nng hn hp

trong thng trn khi quay thng.

z


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Hnh 3.2: S tnh ton cho my trn b tng t do.

dng tng qut cng tiu hao cho mt chu k di chuyn khp kn ca hn hp.

A = GCM.H [J] .

Trong :

GCM: Trng lng hn hp [N].H : Chiu caonng hn hp trong thng trn [m].

Trng lng hn hp trong thng trn :

GCM = V.f.g [N].

V : Dung tch ca hn hp b tng trong thng trn [m3].

V = 0,5 m3.

f : Khi lng ring ca hn hp b tng.

f = 1800 [kg/m3]

g : Gia tc ri t do [m/s2].

g = 9,8 [m/s2]

GCM = 0,5.1800.9,8 = 8820 [N].

Qu o chuyn ng ca hn hp trong thng trn rt phc tp. Mt phn hn hp

c nng ln bng cc cnh trn, phn cn li c nng ln do tc dng ca lc ma st.

Cng sut cn tiu hao nng hn hp:

Nkt =1000

)..()..(222111

ZhGZhG np (Kw).

Trong :

G1: Trng lng hn hp c nng ln do tc dng ca lc ma st.

G1 = 0,85. GCM = 0.85.8820 = 7497 [N].

G2 : Trng lng hn hp c nng ln bng cc cnh trn.

G1 = 0,15. GCM = 0.15.8820 = 1323 [N].

h1np: Chiu cao nng ca hn hp do tc dng ca lc ma st [m].

h2 : Chiu cao nng hn hp bng cnh trn.

Z1, Z2: S lng chu k khp kn ca hn hp sau mt vng quay ca thng

trn c thc hin tng ng do lc ma st v bng cc cnh trn.

n : S vng quay ca thng trn.


10/46



n = 0,3[v/s].

Ta c : h2= R + Rsin = R( 1+ sin)

R : Bn knh trong ca thng trn.

R = 0,57 [m].

Gc c th ly bng gc ma st. = 45

Khi : h2= 0,57.(1+1/) = 0,9731, [m].Chuyn ng ca hn hp di tc dng ca lc ma st phc tp hn so vi trng hp

xt trn. Xt chuyn ng ca phn t hn hp nm trn thnh tang trn, khi thng trn

quay th phn t ny s c nng ln, c xc nh bng gc ma st 1 nhng do chu nh

hng ca cc cnh trn v c t ln cc phn t khc, do gc nng thc 2s ln hn

( khong 90 ) sau phn t ny s b trt xung theo b mt ca hn hp.

Tip nhn gc chuyn dch ca hn hp t im A ti im B 1(2= 90) th chiucao

nng ca hn hp do tc dng ca lc ma st s l:

H1np = R = 0,57 [m].

- S chu k chuyn ng khp kn ca hn hp di tc dng ca lc ma st sau mt

vng quay ca tang trn (coi thi gian m hn hp trt xung v v tr ban u bng thi

gian nng ln ti cao h1np.

Z1 = 22

360

2

0

f

- Thi gian nng cnh trn bng hn hp.

t1 =

0

0

360

901

n

t1 =

0

00

360

4590

3,0

1 = 25,1 [s].

- Thi gian ri t do hn hp t cao h2.

t2 =g

h2

2= 4454,0

81,9

9731.0.2 [s].

S lng chu trnh chuyn ng khp kn ca hn hp do cc cnh trn thc hin c

sau mt vng quay ca tang trn.


11/46



Z2 =21 tt

tv

Trong :

tv =

n

1Thi gian thc hin vng quay ca thng trn [s].

n : Tn s vng quay ca thng trn [v/s].

R : Bn knh thng trn [m].

Vy :

Z2 = 4454,025,13,0

1

=1,9961 2

S lng chu trnh khp kn ca hn hp do cc cnh trn thc hin c sau mt vng

quay ca tang trn l Z2 = 2. iu cho thy rng: s lng chu trnh khp kn ca hnhp cho c hai trng hp xt trn c th coi bng nhau. C ngha l Z1 = Z2 = Z = 2.

Do vy cng sut tiu hao nng hn hp: N1 =1000

....2211 nZhGhG np

Thay cc gi tr vo cng thc trn ta c:

N1=() 3,34 [Kw].

Bn knh ca thng trn vi chnh xc cn thit c th ly bng bn knh phn hnh

trca ni trn, bi l phn hn hp tp trung giai on ny.

Ngoi cng nng hn hp ng c cn phi tiu hao nng lng khc phc lc

ma st cc gi thng trn. Thnh phn cng sut tiu hao n c th c xc nh theo

cng thc sau:

i vimy trn c cm dn ng thng trn trung tm:

N2 =

1000

... oTCM GG

GT: Trng lng thng trn. GT = 9800 N.

: Vn tc gc thng trn. =2n =2.3,14.0.3 = 1,884 [rad/s].

: H s ma st trong trc ca thng trn lp ghp thng trn vi u

trc ra ca hp gim tc. = 0,06.

o : Bn knh ngng trc.

o= 0,06 [m].


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N2 =() 0,07 [Kw].

Cng sut ng c truyn chuyn ng quay cho thng trn.

Nc =

21NN

.

: Hiu sut b truyn. = n. b. br .l

l hiu sut ln l = 0,97

b hiu sut 2 cp bi b = 0,992

n hiu sut cp bnh rng nnh n =0,93

br hiu sut mt cp bnh rng tr knbr =0,98

=0,992.0.98.0,93 .097 0,87

Nc = 3,92 [Kw] 5.2568 (hp)

2.2.3 CHN NG C

Ta c cng sut ca ng c in my trn phn trc l 3,92 kw.

Vy ta chn loi ng c in loi c cc thng s sau y :

K hiu : AO2-42- 4

Cng sut : 5,5 (KW)

S vng quay : 1440 (vng/ pht)

Hiu sut : 88 %

H s cng sut : 0.9

Khi lng : 88 (Kg)

Ni sn xut : Vit Nam

2.3 CHN PHNG N THIT K HP GIM T TC V B TRUYN:


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Da vo kho st mt s my trn btng t do kiu lt ph bin, ta chn kt cu

ca hp gim tc nh sau:

Ta thy i vi my trn btng kiu t do, s vng quay ca thng trn cn phi la

chn sao cho khi quay di tc dng ca lc qun tnh ly tm, hn hp khng b vng ln

dnh vo thnh trong ca thng trn. Trong thc t gia tc ly tm cho php bng 1/5 giatc trng trng v do s vng quay ca thng trn c tr s tng i nh v ph

thuc vo ng knh ca thng trn, thng l 15 40 vng /pht

V vy, m bo s vng quay ca thng trn , sau ng c phi c hp gim tc

vi t s truyn v cng sut ph hp

2.3.2.1 Chn phng n thit trun :

y , s vng quay ca thng trn l nlv =18 vng/pht

Vy t s truyn ton b b truyn l

i = =

=80Gi ivr l t s truyn ca b truyn bnh rng vnh rng v igt l t s truyn ca

hp gim tc. Ta c:

ivr =

=

Chn igt= 10 => ivr = 8

Do vnh rng ph thuc vo ng knh ca thng trn nn t s truyn ivr ca b

truyn bnh rng- vnh rng cng b gii hn bi ng knh thng trn.

2.3.2.2 CHN PHNG N THIT K HP GIM TC:

Tham kho mt s hp gim tc trong my trn btng t do c nh, ta chn hp

gim tc sao cho tha mn t s truyn : igt = 6

Trong thc t, hp gim tc mt cp bnh rng tr rng thng c th c dng viphm vi t s truyn i = 1,25 10. T s truyn i c th ly 6 nu l rng thng v c

th ly ti 10 nu l rng nghing hoc rng ch V

Vy ta chn thit k hp gim tc 1 cp bnh rng tr rng nghing c t s truyn l

igt = 10 v cng sut phi truyn c P= (3,92 5.5 ) KW


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CHNG 3:TNH TON THIT K CHI TIT

3.1 Thit trun nh rng nn rng thng vnh rng nn c t s trun i1 = 8

Chn vt iu ch to :Bnh nh: thp 50 thng ha c:

HB = 230 , b1= 620 N/ mm2, ch1= 320 N/ mm

2Bnh ln(vnh rng) : thp 45 thng ha c :

HB = 160 , b2= 550 N/ mm2, ch2= 270 N/ mm

2* c nh c tc ng :Sau khi qua hp gim tc, s vng quay trn trc bnh rng nn l :

n1 =

=

(vng / pht)

Cng sut sau khi qua hp gim tc:N1= N.gt. olol : hiu sut ca ln = 0,97gt : hiu sut ca hp gim tc = 0,99

2.0,98.N1 = 5,5 . 0,97. 0,98.0,99

2 = 5,1243 (kw)

* nh ng sut tip c v ng sut un cho php : a) ng sut tip xc cho php :Chn :Thi gian s dng = 15000 gi

Thi gian cp liu = 17s = 0,1288 chu kThi gian trn = 90s = 0,6818 chu kThi gian tho liu = 25s =0,1894 chu kTc quay vnh rng = 18 vng/ phtTc bnh rng nn = 144 vng/pht


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S phn b ti trng trong 1 chu k S chu k lm vic ca vnh rng nn :

N =60.18.15000.( 0,52 . 0,1288 + 0,52 . 0,1894 + 12.0,6818 ) =1,2334.107 >107

( Cng thc (3-3) [2])S chu k lm vic ca bnh rng nn :

Nbr =60.144.15000.( 0,52 . 0,1288 + 0,52 . 0,1894 + 12 . 0,6818 ) >107

Do i vi c 2 bnh rng kN = 1ng sut tip xc cho php ( Ti liu [2] - Bng (3-9) )Bnh nh: []tx1 = 2,6 .230 = 598 (N/mm

2)Bnh ln :[]tx2 = 2,6.200 = 520 N/mm

2)

Ly tr s nh []tx2 = 520(N/mm

2

) tnh tonb) ng sut un cho php :S chu k lm vic ca ai nn :

N =60.18.15000.( 0,56 . 0,1288 + 0,56 . 0,1894 + 16 . 0,7274 ) >107

S chu k lm vic ca bnh rng :N =60. 144.15000.( 0,5

6 . 0,1288 + 0,56 . 0,1894 + 16 . 0,7274 )>107

Do i vi c 2 bnh rng kN = 1


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Ly h s an ton ca bnh nh (thp rn ) n= 1,5 v ca bnh ln (thp c) n=1,8 ;H s tp trung ng sut K= 1,8Gii hn mi ca thp 50:

-1 = 0,43 .620 = 266 N/ mm2

Gii hn mi ca thp 45:

-1 = 0,43.550 = 236 N/mm2

ng sut un cho php ca bnh nh:

[]u1 = = 98 N/mm2

ng sut un cho php ca bnh ln :

[]u1 = = 73 N/mm2

L s h s ti trng K=Ktt.K = 1,5 Chn h s chiu rng nh rng:

L = b/L = 0,2

* Tnh chiu i nn : [ cng thc (3-11)/ sch thit k chi tit my]

L ()]] L ()] 469,5629(mm)Chn L= 385,88 (mm) 470

Tnh vn tc vng v cp chnh c ch to nh rng :Vn tc vng (Ti liu [2] - cng thc (3-18) )

v =()

v =() 0,79 (m/s)

Vi vn tc ny c th chn cp chnh xc 9 (Ti liu [2] -bng 3-11) nh chnh c h s ti trng K v chiu i nn LVi v0,79 (m/s) theo(Ti liu [2] - bng[3-13] tm c h s ti trng ngK= 1,1; Ktt bng=1,1Vy h s ti trng : K= K.Ktt = 1,1.1,1= 1,21 khc vi d on trn l 1,5

Tnh li L vi k mi

L ()] 437,1111(mm)L =440 mmV= 0,6474K vn nh cVy chiu di nn:

L = 440 mm c nh mun v s rng:


17/46



Mun ms = 0,02. L = 0,02. 440= 8,8 (mm) [Ti liu [2] -cng thc 3-23]Chn ms = 9 (mm) ( Gi tr chun trong bng 3-1)

Z1 =

= = 15,5929. Chn Z1= 16

Z2 = ivr .Z1 = 8 . 16 = 112 . Chn Z2 = 128

Tnh chnh xc chiu di nn (Ti liu [1] - bng 3-5)L =0,5.ms. =0,5.7 580,4826 (mm)

Chn li sau tnh L ms =12Z1=12Z2=96

Chiu di rng:b= L.L= 0,2 . 580= 116 (mm)

Mun trung bnh:

mtb= mtb = ms( ) = 12.() = 10,80(mm)Kim nghim sc n un crng :Gc mt nn ln bnh nh tnh theo cng thc trong bng 3 -5:

tg1= = = 0,1251 = 707S rng tng ng ca bnh nh (Ti liu [2] - cng thc (3-38) )

Zt1= 12

Gc mt nn ln bnh ln :

tg2 = ivr = 82 = 82053S rng tng ng ca bnh ln:

Zt2 = 774 ( rng)Theo (bng 3-18 )v s rng tng ng tm c h s dng rng :

Bnh nh : y1 = 0,338Bnh ln : y2 = 0,517

ng sut un ti chn bnh nh [Ti liu [2] - cng thc (3-35)]

u1 = =

() = 17,6307 (N/mm2 )< []u1 = 98( N/mm2)ng sut un ti chn rng bnh ln : [Ti liu [2] - cng thc (3-40)]

u2= u1 . = 17,6307.

= 11,5265(N/ mm2 ) < []u2 =73 (N/ mm2) Kim nghim sc n c rng hi chu qu ti trong thi gin ngnng sut tip xc cho php [Ti liu [2] - cng thc (3-43)]


18/46



Bnh nh :[]txqt1= 2,5. []tx1 =2,5 . 598 = 1495 (N/mm

2)Bnh ln :

[]txqt2= 2,5. []tx2 = 2,5. 520 = 1300 (N/mm2 )

ng sut un cho php [Ti liu [2] - cng thc (3-46)]]

Bnh ln:[]uqt1= 0,8. ch1 = 0,8 . 320 = 256 (N/mm

2)Bnh nh:

[]uqt2 = 0,8. ch2 = 0,8 . 270 = 216 ( N/ mm2)

Ch cn kim nghim sc bn tip xc i vi bnh ln, c [ ] txqt nh hn [Ti liu[2] -cng thc (3-15) v (3-41)]:

txqt= tx .vi:

tx = () () = () () = 340,2116 (N/mm2 ) txqt = . 340,2116= 356,8169 ( N/mm2 ) < []txqt2 = 1300 (N/mm2 )

Kim nghim sc bn un [Ti liu [2] -cng thc (3-39) v (3-42) ]Bnh nh : uqt1= u1 .2 = 17,6307. 2 =35,2614 (N /mm

2) < [ uqt1] = 256(N/mm2)

Bnh ln : uqt2= u2 .2 = 11,5265 .2 = 23,0530 (N /mm2) < [ uqt2] = 216 (N/mm

2) Cc thng s hnh hc ch u c trun :

Mun mt mt ln : ms= 12 (mm)S rng : Z1 =12 ; Z2 =96Chiu di rng : b= 116 (mm)Chiu di nn : L = 580(mm)Gc n khp : = 200Gc mt nn chia (cng l gc mt nn ln ):1 = 70 7 ; 2 = 82053ng knh vng chia ( vng ln):

d1 = ms .Z1 = 12.12 =144 (mm)d2 = ms.Z2 = 12.96 = 1152 (mm)

ng knh vng nh :De1 = ms. (Z1+2 cos 1) = 12.(12 + 2.cos(707)) 167,8151(mm)Ly De1 = 168 (mm)De2 = ms. (Z2+2 cos 2) = 12. (112 + 2.cos( 82053)) 1175,8151(mm)Ly De2 = 1176 (mm)

ng knh vng chia trung bnh ;

dtb1= d1(10,5 ) = 144.(1- 0,5

) = 129,6 (mm)


19/46



dtb2 = d2(10,5 ) = 1152.(1- 0,5

) = 1036,8(mm)Gc chn rng : = 1= 2 = acrtg ( )= acrtg ( ) =10 29Gc nh rng : = 1= 2 = acrtg( ) = acrtg ( ) = 10 11Gc mt nn chn rng :

i1 = 1 - = 70 7- 10 29 = 5 0 38i2 = 2 - = 82053 - 10 29 = 810 24Gc mt nn nh rng :e1 = 1 + = 70 7 +10 11 = 8 0 18e2 = 2 + = 82053+10 11 = 840 04* Tnh lc tc dng :i vi bnh rng nn :Mmen xon trn trc bnh rng nn :

= 9,55.106

. = 9,55.106

. = 339840,7792 (N.mm)Lc vng :P1 =

= = = 5244,4557 (N)

Lc hng tm:Pr1 = P1tg.cos 1 = 5244,4557. 0,364.0,992 = 1893,71 (N)

Lc dc trc:Pa1 = P1. tg.sin1 = 5244,4557. 0,364.0,124 = 236,7138 (N)

i vi bnh rng ln:

Lc vng:P2 = P1 = 5244,4557 (N) = 534,603 (kg)

Lc hng tm :Pr2 = Pa1 = 236,7138 (N) = 24,1298 (kg)

Lc dc trc :Pa2 = P r1 = 1893,71 (N) =193,0387 (kg)

* Kt qu tnh ton cc thng s hnh hc ch yu dng trong bn v ca b truynnh rng nn vnh rng nn c t s truyn ivr = 8


20/46

n thit k my GVHD: V Nh Thnh

SVTH : Nguyn ngc nh Page 20

L = (mm)ms = 7 (mm)Z1 = 12 (rng)

Z2 = 96 (rng)d1 = 144 (mm)d2 = 1152 (mm)dtb1 = 129,6 (mm)dtb2 = 1035,8 (mm)De1 = 168 (mm)De2 = 1176 (mm)1 = 70 72 = 82

0

53i1 = 5 0 38i2 = 810 24e1 = 8 0 18e2 = 840 043.2 HP GIM TC (TI LIU THAM KHO CH YU L [1])

Cc thng s ly theo (g li thnh GOST ) 2185-55

Vn tc trc chm hp gim tc khi dng t s truyn igt =10

nt = nb/ igt =1440/10=144(vng /pht)

nt : vn tc vo hp gim tc

nt=ndc= 1440(vng/pht)

nb : vn tc ra hp gim tc

3.2.1CHN VT LIU CA CC BNH RNG V C NH NG SUTCHO PHP

1. Theo bng 9 ,chng v [1] . i vi bnh rng nh dng thp 40XH c c tnh (bng 11[1] ) : b= 90 kg/mm

2, T = 70 kg/mm2, HB= 265 -295, nhit luyn: lm tt (

ng knh ca phi bnh rng nh ly trong gii hn n 120 mm )

Bnh rng ln dng thp 40x vi c tnh b= 75 kg/mm2, T = 50 kg/mm

2, HB= 215 -243, nhit luyn: lm tt ( ng knh ca phi bnh rng nh ly trong gii hn n250 mm )


21/46



2. Xc nh ng sut tip xc ct cho php ca vt liu bnh rng ln.

Tnh gii hn mi -1 0,35.b + (712) = 0,35.75 + (712) = 33,2538,25 kg/mm2

Ly -1 = 35 kg/mm2

[]ck 0,48. -1 =0,48.35 =16,8 kg/mm2

3. Xc nh ng sut un cho php khi ti trng tc ng mt chiu bng cng thc

[0]u =

Gii hn mi ca bnh rng nh trong chu ki xng xc nh bng cng thc :

-1 0,35.b + (712) = 0,35.90 + (712) = 38,543,5 kg/mm2

Ly -1 = 40 kg/mm2 .

Theo trang 91; 92 [1]

n =1,4 (h s an ton bn )

k = 1,6 (h s tp trung ng sut)

[0]u == 25 kg/mm2

Vi bnh rng ln c cng k v n :

[0]u == 21,875 kg/mm2

3.2.2 C NH KHONG CCH TM V KCH THC CHNH CABNH RNG THEO SC BN TIP XC

Cng thc tnh

A=863.(igt+1) ] 3.2.2.1 Ly h s chiu rng bnh rng A = 0,4


22/46



3.2.2.2Xc nh m men trn trc ra ca hp gim tc .

H s ti trng : ktt = kl kttr

Xem trang 8386 [1]Kttr = 1 ( h s tp trung ti trng )Kl = 1,1 ( h sng lc )Coi m men truyn qua hp gim tc l cnh : k = 1.1mmen tnh trn tc quay chm = 5,2568.1,1 / 144 = 0,0402 N : cng sut cn ca ng c

3.2.2.3 Xc nh khong cch tm

A=863.(10+1) =144,9615 mmTheo GOST 218555( xem bng 8 ph lc [1] )

Chn A= 150 mm

3.2.2.4 Xc nh m un n khp :mn=(0,01

0.02).A

theo GOST 218555( xem bng 9 ph lc [1] ) chn mn = 1.5

3.2.2.5Xc nh tng srng v chn gc nghing ca rng

A =

Zc= =

= 200 cos Chn = 8 6 34,61 , cos = 0.99 , vy zc = 198

3.2.2.6 Xc nh srng

Srng bnh nh ZIII =()= 198/11=18

Srng bnh ln Zk = zc-zIII = 198-18= 180

Theo srng th i= = =10 tc l trng vi t s truyn ng yu cu3.2.2.7 Xc nh ng knh


23/46



Bnh rng nh DIII = (mn.zIII)/cos = 1,5.18/0,99 =27,3 mmBnh rng ln Dk = (mn.zk)/cos = 1,5.180/0,99 =272,7 mmNghim li

3.2.2.8 Xc nh chiu rng bnh rng

b = A .A =0,4. 150 =60 mm3.2.2.9 NGHIMTI T S CHIU RNG V NG KNH BNHRNG NH

= 60/27,3 = 2,1798 >1,5

Theo iu kin trang 77[1] , th A c tnh nh trn l khng ph hpTrong cng thc tnh A, ch A l c ththay i cChn cosnh trn , vi mn =0,01.A, ta vn c srng khng iTheo iu kin trang 77[1]A = = 0,1772chn A = 0,2theo cch tnh nh trn , sau khi tnh li vi

A = 0,2

A= 182,64Theo GOST 218555( xem bng 8 ph lc [1] )Chn A= 200 mm mn = 2

ng knh haibnh rng sau khi tnh li vi mn = 2Bnh rng nh DIII = (mn.zIII)/cos = 2.18/0,99 =36,4 mmBnh rng ln Dk = (mn.zk)/cos =2.180/0,99 =363,6 mmb = A .A =0,2. 200 =40 mm

= 40/36,4 = 1,0989 < 1,5 (t yu cu)

3.2.2.10 Nghim li ng sut tip xc thc theo kch thc n khp ca bnhrng

Cng thc tnh

= ()


24/46



vn tc vng ca bnh rng

v =

=

= 2,7431 m/s

vi vn tc ny, cn ch to bnh rng vi hng chnh xc 9 (trang 84[1])

Nghim li t s: b = A.A (thonh tnh trn)Vn tc vng thp hn 3m/s v b = A.A nn h s k c sa lithnh k= 1 , sau khi tnh li vi cc thng sA,k sa th A = 176,8554mm , vn chn A=200 mm

Tuy nhin

0,0365

= () =13,9411 kg/mm2< [ ]ck

3.2.3 Nghim rng cc nh rng theo ng sut un

u = [0]u

1. Xc nh h s dng rng cho cc bnh rng. Srng thay thzIII = =18/(0,99^3) 19zk =

=180/(0,99^3) 186h s dng rng (ly theo gi tr trung bnh t bng 5 chng v [1]) , ivi bnh rng nh y1 = 0, 386 , i vi bnh rng ln y2 = 0,528

2. nh gi bn tng i gia rng bnh nhv rng bnh ln theo uni vibnh rng nh :y1.[0]u = 0,386.25= 9,65 kg/mm

2

i vi bnh rng ln :y2.[0]u = 0,528.21,875= 11,55 kg/mm

2Vy bn bnh rng nh nhhn nn sau ny, ta tnh ton theo bnh nhng lc vng :P = 75.N/v = 75.5,2568/2,7431 = 143,7279 kgy v= 2,7431 m/s (nh tnh)

3. Xc nh ng sut un tit din nguy him ca rng bnh nh. Ly cos =cos 20=0,94; k=1,55, k=1

u=

= 2,1297 < []u


25/46



3.2.4 Tnh trc v chn trc

3.2.4.1Xc nh ng knh u ra ca trc quay nhanh theo xon (tnh ton s

b)

d= ] Mk = Mb = 71620.

=71620. 5,2568/1440 = 261,4528 kg.cmLy [ ]k =250 kg/cm

2(bi 26 [ 1 ]) . m bo cng cao cho trc (cbit quan trng khi chiu rng bnh rng tng i ln), phi chn tr s nh nht cang sut cho php

db = = 1,7359 cmtr s cui cng ca ng knh trc sc xc nh sau khi chn trc

3.2.4.2V phc cu to trc quay nhanh hp gim tc

Mc ch ca vic v phc cu to l xc nh vtr tng i ca nhng bnh rngv trc , v do xc nh ti trng trn trc v thit lp biu m men un cn

thit khi tnh gn ng trc.

Trong bn v, bt u vng tm trc v ng trung bnh ca bnh rng nh,t 2 bn ng nhng on b/2 v vch ng chu vi bnh rng nh.

Chiu di u ra ca trc quay nhanh ly bng 62 mm da theo chiu di khp nitrc vng n hi ng vi ng knh trc ng c dc =28 mm

Khong cch tvai u ra ca trc n bi ly bng 40 mm sau ny c ch lpnp trc v cc b phn lt kn trn np, ng thi c mt khong t do trongkhoang trc, t mt trong ca np n trc )

Cho ng knh ca phn trc nm trong trc l 20-25 mm, dng bi , ctrungbnh ly chiu rng ca bng 25 mm

T mt u ca trc n thnh v l 8mm ( y dng vng chn du hay vng gtdu tu theo h thng bi trn ) v tbnh rng n thnh v l 12mm. Bi v ng


26/46



knh bnh rng khng ln hn ng knh trc my , nn lm lin vi trc (trn bngv phc khng v)

Bng v phc cu to v lc tnh trc l cn c vo bn v phc nyXc nh ng lc tc ng chn khp. ng lc vng (nh trn)

3.2.4.3xc nh ng lc tc ng chn khp

ng lc vng (nh trn): P = 143,7279 kg

ng lc xuyn tm :

T =

= 143,7279.

=52,8411 kg

ng lc chiu trc :

A = P. tan = 143,7279. Tan =20,4801 kg3.2.4.4Xc nh cc phn lc gi ta (ti trng ln trc )

RAX = RBX = =143,7279 / 2 =71,864 kg

= 0RAy =

= = 29,9704 kg

RBy = TRAy = 52,841129,9704 =22,8707 kg

Trong l : khong cch gia 2 tm trc l= 25 +(8+12).2 + 40 =105 mm

3.2.4.5 Chn trc - v lc chiu trc chn khp khng nh nn ta chn bi A ti trng ln hn, do tnh ton theo ny * ti trng hng tm tng cng :

=

= 77,8631 kg


27/46



Ti trng thu gn

QA =(RA . kk +m.A).k.kT ; m= 1,5 (bng 48 [1]) ;k = 1,3 (bng 49 [1]); kk = 1,0 ;

kT = 1,0 (bi 34 [1]) ch thchQA= (77,8631.1,0 + 1,5.20,4801 ).1,3.1,0 = 141,1582 kg

Chn trc cn c vo tui bn h= 5000 gi. H s khnng lm vic cn thit ca trc

C = QA.(n.h)0,3 = 137,8539. () = 16102,9654

Theo katalo (bng 14 ph lc [1]) ly trc N 304 vi C =19000 tuy nhin sphi tnh li chu trnh trn vi b rng bi B= 15 mm tc l mi :

l = 20.2 +40 + 2.15/2 =95 mm

Sau khi tnh li vi l mi ta c

RAy = 30,1641 kg

RA = 77,9378 kg

RBy = 22,317 kg

QA = 141,2553 kg

C = 16114,0424

Vn tho mn C ca chn

3.2.4.6 Tnh gn ng trc khi chu tc dng ng thi un xon

S btnh chnh xc ng knh ca trc . ch lp trc , dn = 20 mm

( trc c ng knh nhhn th h s khnng lm vic 0 ), ng knh u raca trc tng ln t nhiu so vi ng knh tnh s b( trnh s khc nhau qu lngia ng knh ch lp trc v u ra ) ly db =35

GOST 6270. ng knh ca trc gia ly bng ng knh vng chn rng bnhrng nh

d = DiIII =DIII2,4.mn = 36,4 - 2,4.2= 31,6 (mm)

thit lp biu m men ( hnh v ). M men xon


28/46



MK = Mb = 261,4528 kg.cm

M men un do lc P tit din gia

My = MP = = (143,7279.9,5) /4 =341,3538 kg.cmM men un do lc T v A (ln nht) tit din rt gn gia trc (bn tri)

Mx = RAy . = 30,1641.4,75 = 143,2795 kg.cm

M men thu gn(tng ng) tit din gia (theo thuyt thnng bin dng trongsc bn )

Mkb = = = 433,9581 kg.cm

ng sut thu gn vi tit din gia

kb = = = 137,5266 kg/cm2 < [-1]u

[-1]u = 600 kg/cm2

3.2.4.7 Xc nh ng knh u ra ca trc quay chm theo xon

dT = ] Mk = Mt = 71620.

=71620. 5,2568/144= 2614,5279 kg.cm

dT =

= 3,7395 cm

theo GOST 6636-53( 6270)

ly dT =40 mm

3.2.4.8 Tnh ton gn ng trc quay chm chu tc dng ng thi ca un v xon

Vic phc ho cu to ca trc tin hnh tng tnh i vi trc quay nhanh. Ccng knh ca trc xc nh theo cu to cn cvo ng knh u ra ca trc . trc, ta ly dn =50mm v ch lp bnh rng ly d = 55 mm


29/46



Bn v trc , cc lc tnh ton v biu m men trnh by trn hnh 236

RCX = RDX =

=143,7279 / 2 =71,864 kg

= 0RDy =

= = 65,613 kg

RCy = TRDy = 52,841165,613 = 12,7719 kg

RCy c chiu ngc vi RDy

3.2.4.9 Chn trc quay chm - v lc chiu trc chn khp khng nh nn tachn bi D ti trng ln hn, do tnh ton theo ny * ti trng hng

tm tng cng : = = 97,3114 kgTi trng thu gn

QD =(RD . kk +m.A).k.kT ; m= 1,5 (bng 48 [1]) ;k = 1,3 (bng 49 [1]); kk = 1,0 ;kT = 1,0 (bi 34 [1]) ch thch

QD= (97,3114.1,0 + 1,5.20,4801 ).1,3.1,0 = 166,441 kg


C = QD.(n.h)0,3 = 166,441. () = 9516,1234

Chn trc N210 vi C = 42000 cao hn nhiu so vi tr s cn thit

3.2.4.10 Tnh gn ng trc quay chm khi chu tc dng ng thi un xon



30/46



MK = MT = 2614,5279 kg.cm


My = MP = = (143,7279.9,5) /4 =341,3538 kg.cmM men un do lc T v A (ln nht) tit din rt gn gia trc (bn tri)

Mx = RDy . = 65,613.4,75 = 311,6618 kg.cm


Mkb = = = 2310,9463 kg.cm

ng sut thu gn vi tit din gia

kb = = = 138,8999 kg/cm2 < [-1]u

[-1]u = 600 kg/cm2

( cng c th)

3.2.5 Chn v nghim then

3.2.5.1 chn then cho trc quay nhanhtheo GOST 8788-58 (bng 28[1]) th ngknh l 20mm ly b x h = 6 mm x 6 mm chiu di ca then da theo chiu di may na khp ni trc ly chng l= 62 mm, vi cc kch thc chn ,ng sut dp cathen l

dp = () = () = 155,6267 kg/cm2 < []dp3.2.5.2 chn then lp bnh rng trc quay chm

Ly b x h = 16 mm x 10 mm v l= 55 mm (km chiu di may bnh rng l 5 mm)

dp =() =

() = 487,5577 kg/cm2 < []dp[]dp =1000-1200 kg/cm

2 i vi moay- thp


31/46



3.2.6bi trn phn n khp v trc

bnh rng bi trn bng cch ngm du, cn trc th dng cch t du

theo vn tc vng ca bnh rng v= 2,7431 m/s nh c d nht cn thit ca du

50 = 118 ccm (bng 68 [1]) loi du xi lanh nh (bng 70 [1]) thch hp vi nhtny

3.2.7 Tnh ton cu to hp gim tc

Cc kch thc c trong [1]

Chiu dy thn hp = 0,025.A +5 = 0,025.200 + 5 = 10 (mm)

Chiu dy np hp 1 = 0.02.A +5 = 0,025.200 + 5 = 9 (mm)Chiu dy vnh thn hp b = 1,5 =1,5.10 = 15 (mm)Chiu dy vnh np hp b1=1,5.1 = 1,5.9 = 13,5 (mm)Chiu dy mt 0 c phn li ln p =2,35. = 23,5 v khi c phn li ln p=1,5 =15 v p2 = (2,252,75) =22,5 27.5( mm)Chiu dy ca np thn hp m = 0,85. = 8,5 mmChiu dy ca np np hp m1= 0,85. 1 = 0,85.9 = 7,65 mmng knh bu long nn d =0,036.A +12 = 0,036.200 +12 = 19,2 mmChn ren M20ng knh bu long ch lp trc d1 =0,75.d =0,75.19,2 = 14,4 mmChn ren M16ng knh bu long lp ghp np v thn hp d2 = (0,50,6) d =9,611,52mm .Chn ren M10ng knh bu long ca np y trc d3=(0,40,5)d = 7,689,6 mmChn ren M8ng knh bu long np l kim sot d4=(0,30,4)d = 5,767,68 mmChn ren M8

Khong cch c1 t mt ngoi ca thnh vn ng trung bnh ca bu lngtutheo ng knh ca bu long d,d1,d2 chn theo bng 65 [1] tu theong knh ca bu lng hay theo cng thc c1 1,2.d+(58) mmng vi d, c1min= 30 ; c2min= 26 (mm)ng vi d1, c1min=26 ; c2min= 21 (mm)ng vi d2. c1min= 18; c2min= 14 (mm)Chiu rng ca thn hp (0 c phn li ln ) v vnh thn hp k : k = c1+c2theo bng 65 [1] vy k = 56 mm ng vi d ; k2= 32 mm ng vi d 2


32/46



Phi b tr cht bu long d1phn li ra ca cht trc . Nn b tr cht bu lng ht sc gn ng tm tc gim bin dng ca thn v np,khong cch t gii hn doa ca trc n trc ca bu long d1 ly bng e

(11,2)d1=16 + 19,2 . Dng hnh v nghim li trnh hin tngbulong d1 v bulong np trc xuyn vo nhauCc ng knh D D1 D2 chn tutheo ng knh ca trc theo cu toc chn ca np trc tu theo c ng lt hay 0

Slng bu long nn n=y L v B l chiu rng v chiu di ca

thn v hpL=2.A +Khong hnh nht gia mt ngoi ca bnh rng vi mt trong ca thnh vhp a =1,2.

Khong hgia mt u bnh rng vi mt trong ca thnh v hp a1 =

Thn v np c nh vtng i bng 2 cht hnh nn lp vo trc khi giacng lt trc. Quy chun cht tra trong bng 60 [1]

Thn v np hp ghp bng 1 slng ln bu long m bo tnh cht knca hp. trnh tnh trng du b r r qua mt ghp ca np v thn hp rangoi, bi trn hay 1 cht nha dnh ln ch ghp. Gia 2 mt ghp ca np vthn hp khng dng m trnh tnh trng lp ghp ca l trc vi trc

khng chnh xc. nhng hp gim tc c mt lp ghp nm ngang, trnh tnhtrng du r r qua mt ghp ra ngoi, i khi ngi ta phay mt rnh mt ghp cha du . Du ng li rnh s theo l thnh chy vy hp

kim sot v du, trn np hp gim tc c l kim tra, l ny c np ykn

Kch thc ca np v bu lng ghp xem hnh 178 [1]

Trong cc hp gim tc pht nhit nhiu trnh tnh trng p lc ca khng kh

bn trong hp ln cao khin cho khng kh v c du rqua m ca np trc(hay qua np l kim tra), ngi ta lp nt c lthng hi . Cu to v kch thclthng hi tra bng 61 [1]

Trn vnh ca np hp gim tc thng c lp thm 2 bu long vi mc ch khi tho hp gim tc vn 2 bu lng th np hp s bnh ln d tho (hnh177 [1])

Cc trc ca hp c np y bng gang c C 12-28 v C 15-32


33/46



nng np hp hay nng c hp gim tc loi nhe ngi ta dng cc bu longvng. ng knh bu long vng chn theo trng lng hp gim tc trong bng63[1] bng 64[1[ cho s b trng lng mt s loi hp gim tc

V cu to ca v hp c phi m bo nhng yu cu v nghing c ,bn knh gc ln v vkch thc chuyn tip (bng 66 67 [1]) . gc ln canhng chi tit my c xc nh nh sau : i vi thnh dy 25 mm th ly 1/3 vti thnh dy hn th ly bng 1/5 trung bnh cng chiu dy ca cc thnh ni tipnhau

Cc quy chun cho cc rnh (gost 2716-44) nh sau : 1, 2,3,5,,8,10,15,20,25,30,40 mm

Hp gim tc v ng c in thng lp trn 1 tm bng gang c hay 1 tmbng thp hn ghp cht bng bu long vi hp gim tc . Slng bu lng v ng knh ca n chn theo nhng cng thc kinh nghm nh trn . Sau khiquy nh v tr ca bu long ri th nghm li sc bn

Lc , nu thy ti trng ca bu long cha cng khng nn gim ng knhhay slng bu long.. Nhng tri li, nu ng sut trong bu long ln hn ngsut cho php

Cc kch thc b sungChiu dy (khng c phn li ) s`1=1.3 d =26 mm

Tnh ton bnh rng

Bnh rng ln

Bnh rng c ng knh ln hn 200 mm v nhhn 500 mm nn l loi

bnh rng rn c khot lm v c 4 l

M un mn =2

ng knh vng chia dc2 = 363.6 mm

Chiu cao rng h = 2,25mn =4,5 mm

Chiu cao u rng h = mn=2 mm

hhng tm c =0,25mn =0,5 mm


34/46



ng knh vng chn rng Di2 = dc2- 2mn -2c =358,6 mm

ng knh vng nh rng De2 = dc2+ 2mn = 367,6 mm

ng knh moay dm2 =1,6.db vi db2=55 mm l ng knh trc ti bnhrng => dm2 = 88 mm

ng knh trong vnh a Do2 =De2-10.mn= 347,6 mm

ng knh vng ttn tm cc l trn a D=0,6.(Do2+dm2) = 273,4

ng knh ltrn a d02=0,25.(D0-dm)= 65 mm

Chiu dy a K= 0,5b =20 mm

Chiu di moay lm =[1.0;1,5]db chn lm=60 mm

Bnh rng nh

Bnh rng c ng knh nh vi ng knh vng y t chnh lch so ving knh trc nn c ch to lin trc

M un mn =2

ng knh vng chia dc1 = 36.4 mmChiu cao rng h = 2,25mn =4,5 mm

Chiu cao u rng h = mn=2 mm

hhng tm c =0,25mn =0,5 mm

ng knh vng chn rng Di1 = dc22,4mn =31,6 mm

ng knh vng nh rng De1= dc2+ 2mn = 40,4 mm

Cn c vo bn v phc hp gim tc v cc tnh ton thc hin , xc nh cu tohp gim tc dng chng ca hp gim tc . dng chung ca hp gim tc c trnhby trn hnh vi 2 hnh chiu


35/46



3.2.7 tnh chnh xc trc

Cn c vo bn v hp gim tc v cc kch thc sau cng cho trn bn v m tnh

chnh xc trcMc ch ca vic tnh chnh xc trc l xc nh h s an ton thc nhng tit dinnguy him ca trc

3.2.7.1Xc nh h s an ton trc quay nhanh . i vi tit din trng tit din giabnh rng nh khng cn xc nh h s an ton v ng sut gi trong tit din nyrt nh. H s an ton rt cao

Xc nh h san ton i vi tit din u ra ca trc c kn s tp trung ng

sut rnh then. i vi thp 40XH -1 = 35 kg/mm2

; -1= 0,58 ; -1 = 0,58.35 =20,3kg/mm2

H s an ton

n = n =

bin v ng sut trung bnh ca chu k tip (ng sut thay i theo chu kmnhng ).

V = m = =

M men cn c cc theo tit din rng

Wp rng = () = () = 1,4279 cm3

y t = 3,5 mm, b= 6 mm(bng 28[1])

V = m = = =91,5515 kg/cm2* =0,83 (bng 23[1]); k1,77 (bng26[1]); = 0,1 (bi 16[1])

n=n= = 9,9319

3.2.7.2xc nh h s an ton cho tit din ca trc quay chm ch gia bnhrng


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Ly vt liu l thp 45 vi c tnh

B = 60 kg/mm2 , T = 30 kg/mm

2

-1 0,43.B = 0,43.60 = 25,8 kg/mm2

-1 0,58.-1 = 0,58.25,8 = 14,964 kg/mm2

Nu ng sut php thay i theo chu ki xng th h s an ton theo ng sutphp l

n =

Bin ca ng sut php

v = max =

M= = = 462,2288Wrng= () = () = () = 14,5156 cm3v = = 31,8436 kg/cm2H s an ton theo ng sut php

0,8 ; k =1,67

n = =38,8125

H s an ton ng sut tip thay i theo chu k mch ng

n =


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v= m =

wp rng = () = () = () = 30,8495 cm3v= m =

= 42,3755 kg/cm2 =0,69 ; k= 1,52 ; =0,1

n = = 15,3341

H s an ton tng qut tnh theo cng thc (115)[1]

= +

n = = = 14,2614ng nh ta mong i, kt qu tnh gn ng h s an ton rt ln

H san ton i vi u ra ca trc quay chm c xc nh cng nh trc quaynhanh , nhng ch tnh theo ng sut tip (y khng tin hnh tnh ton, nhng theokt qu ca vic nh h s an ton tit din gia v nu ch rng tr sng sutcho php ly rt thp khi tnh gn ng , c th tin rng h s an ton tit din nyrt cao)

3.2.8 tnh nghim bu lng nn

Lc tc dng ln bu lng chu ti trng ln nht, tnh theo cng thc (149)[1]:

P1x =()

(Monpx = M lt quanh trc x)


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Khng kn m men gy ra bi trng lng hp gim tc c :

Monpx = Mb + Mr = 261,4528+2614,5279 = 2875,9807 kg.cm

Theo hnh v(hnh ) l1x = ;l2x =

P1x =()

Chn bu lng nn c ren M 20. ng sut tnh trong bu lng chu ti trng ln nht l

=

=

= kg/cm2< []p

[]p = (bi 40 [1])

kt lun phn ny , cn ch mt sc im cu to ca hp gim tc cthit k (hnh 237)

1. nhng vng trong ca dc lp cht vi trc nh di ( ch to ch lp ghptheo ghp cng hng chnh xc 2 trong h thng l )

2. nhng trc lp trn nhng ng lt c bit, cc ng lt ny cng ng thi l np

3. khong hnhit gia vnh ngoi ca v np c bo m nhbm kim loiiu chnh, cc ming m c t trn nhng ci ggia np v thn

4. nhng np trc thng, c nhng b phn lm kn ch to lin trn np

5. hn ch du vng vo , trn trc quay nhanh t vng chn du 6

6. bnh rng cnh trn trc nhmt bn l vai trc, bn kia l mt ng lt

7. kim sot mc du, dng thc ch mc du cn c vo nguyn tc bnh thngy

8. nt tho du(chi tit 10), cho du chy ra c thun tin, cn t v tr thpnht ca hp gim tc

9. mun du v thnh thong xem xt hp gim tc, dng mt ci ca trn np14ca ny c mt nt thng hi 15

3.2.7 Bng cc iu p, tr s si ch gii hn v ung si p ghp :


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Kiu lp ghp: Ta chn kiu lp ghp chung l H7/k6 (dng chomi ghp khng yu

cu tho lp thng xuyn, tho khng thun tin hoc c th gy h hi cc chi tit

c ghp; kh nng nh tm ca mi ghp cao hn khi m bo chiu di may l (1,2..1,5)d (d - ng knh trc), chng hn lp bnh rng, vng trong ln, a xch

ln trc, lp cc lt, tang quay; cc chi tit cn phng quay v di trt), mt s kiu

lp khc phi dng kiu lp lng D8/k6 (v d bc lt vi trc)

Bng k cc kiu lp ghp tra theo bng5[3]

30cho H7,

5[3]

31cho D8,

4[3]

27cho

d11,

4

[3]23 cho k6 :

Kiu lp gia

Trc 1 Trc 2 Trc 3

Kiu

lp

Dung

sai

Kiu

lp

Dung

sai

Kiu lp Dung

sai

(m) (m) (m)

Ni trc n hi

trc65

6

7

k

H

+30

0

+21

+2

ln trc 35k6 +18

+2

45k6 +18

+2

70k6 +21

+2

V hp ln 72H7 +30

0

85H7 +35

0

110H7 +35

0

Bnh rng trc30

6

7

k

H

+21

052

6

7

k

H

+30

075

6

7

k

H

+30

0

+15

+2

+21

+2

+21

+2

+98

+65

+119

+80

+146

+100


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Vng chn m trc30

8

6

D

k

+15

+245

8

6

D

k

+18

+270

8

6

D

k

+21

+2

Np v hp72

7

11

H

d

+300

857

11

H

d

+350

1107

11

H

d

+350

-100

-290

-120

-340

-120

-340

Cc lt V hp92

7

6

H

k

+35

0

+25

+3

Bc lt Trc65

8

6

D

k

+146

+100

+21

+2

3.2.8 Chn v tnh ton ni trc.

* Chn khp ni: Chn khp ni ta cn da vo iu kin lm vic c cu v iukin kinh t m chn loi khp ni thit k.Yu cu y l khp ni cn m boiu kin sau:

+ Moment xon ln.+ C cu nh gn.+ Lm vic an ton.+ D gia cng ,d ch to.+ Gim va p, chn ng.

Da vo nhng yu cu trn ta chn phng n ni trc vng n hi.V loi ny m

bo cho h thng lm vic an ton trnh lm vic trong iu kin qu ti cho php cthgy h hng.Gi thnh khng cao v d gia cng ch to lp rp.* Tnh ton ni trc vng n hi gia trc ng c v trc u vo hp gimtc:

Thng s : N = 5,5 Kw ; n = 1440 v/ph ; d = 20 (mm )Mmen xon truyn qua ni trc:

Mx= 9,55.106. (N/n) = 9,55.106 . (5,5/ 1440)= 36,475 (N.m)

Mmen tnh:Mt = K.Mx =1,5. 36,475 = 54,71 (N.m)


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Theo tr smmen tnh v ng knh trc chn kch thc ni trc [Ti liu [2]-bng 9-11) - [1] )cc k hiu xem [Ti liu [2]- hnh (9-13) ]

d= 28(mm) ; D=120 (mm) d0= 28 (mm)l= 62 (mm) c=4 (mm) D0 =78 (mm)

Kch thc cht:

dc = 14 (mm) lc = 32(mm) Ren M10

s cht : Z= 4

Kch thc vng n hi :

ng knh ngoi 27 mm

Chiu di ton b cc vng lv = 28(mm)

Chn vt liu: Ni trc lm bng gang C 21-40, cht bng thp 45 thng ha, vng

n hi bng cao su

ng sut cho php ca vng su l []d = 2 N/mm2

ng sut un cho php ca cht []u = 60N/mm2

Ti liu tham kho

[1]: thit k mn hc chi tit myK.N. BKV, GH.M. ITSKVITCH,V.A. KIXLIEV, S.A. TCHECNAVSKI-Nh xut bn gio dc 1963

[2]: Thit k chi tit my-Nguyn Trng Hip, Nguyn Vn Lm - Nh xutbn gio dc 1999(ti bn ln th 14 )

[3]: My xy dng( phn bi tp)Phm Quang Dng, Nguyn Vn Hng,

Lu B Thun - nh xut bn khoa hc k thut[4]: Hng dn thit k n mn hc chi tit my-tm tt 2009


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Chnh sa trc 2Trucj 2

Ca mnh

3.2.4.7 Xc nh ng knh u ra ca trc quay chm theo xon

dT = ] Mk = Mt = 71620. =71620. 5,2568/144= 2614,5279 kg.cm

dT = = 3,7395 cmtheo GOST 6636-53( 6270)

ly dT =40 mm

3.2.4.8 Tnh ton gn ng trc quay chm chu tc dng ng thi ca un v xonVic phc ho cu to ca trc tin hnh tng tnh i vi trc quay nhanh. Ccng knh ca trc xc nh theo cu to cn cvo ng knh u ra ca trc . trc, ta ly dn =50mm v ch lp bnh rng ly d = 55 mm

Bn v trc , cc lc tnh ton v biu m men trnh by trn hnh

RCX = RDX = =143,7279 / 2 =71,864 kg

= 0RDy =

= = 65,613 kg


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RCy = TRDy = 52,841165,613 = 12,7719 kg

RCy c chiu ngc vi RDy

3.2.4.9 Chn trc quay chm - v lc chiu trc chn khp khng nh nn tachn bi D ti trng ln hn, do tnh ton theo ny* ti trng hng tm

tng cng : = = 97,3114 kgTi trng thu gn

QD

=(RD

. kk

+m.A).k.k

T; m= 1,5 (bng 48 [1]) ;k

= 1,3 (bng 49 [1]); k

k= 1,0 ;

kT = 1,0 (bi 34 [1]) ch thch

QD= (97,3114.1,0 + 1,5.20,4801 ).1,3.1,0 = 166,441 kg


C = QD.(n.h)0,3 = 166,441. () = 9516,1234

Chn trc N210 vi C = 42000 cao hn nhiu so vi tr s cn thit

3.2.4.10 Tnh gn ng trc quay chm khi chu tc dng ng thi un xon


MK = MT = 2614,5279 kg.cm


My = MP =

= (143,7279.9,5) /4 =341,3538 kg.cm

M men un do lc T v A (ln nht) tit din rt gn gia trc (bn tri)

Mx = RDy . = 65,613.4,75 = 311,6618 kg.cm


Mkb =


44/46



= = 2310,9463 kg.cmng sut thu gn vi tit din gia

kb = = = 138,8999 kg/cm2 < [-1]u[-1]u = 600 kg/cm

2

( cng c th)

Ca b nam

P2Trc II :

RCx

RCy RDx

a b l

C: P2 =1324 (N) ; Pr2 = 482 (N) ;

b = a = 40 mm ; (a+b) = 80 (mm) ; l=76 (mm)

d2l ng knh vng chia bnh rng b dn trn trc II, d 2 = 363,6 (mm)

Lc vng ca bnh rng nn : Pn1 = 4277 (N)

Lc hng tm ca bnh rng nn: Pn r1 =1545 (N)

Lc dc trc ca bnh rng nn : Pna1=193 (N)

Pna

1

Pnr1

Pn1


45/46



ng knh vng chia trung bnh ca bnh rng nn : dtb1 = 88,2 (mm)

Tnh phn lc cc gi :

mCy = Pr2.a+ RDy.(a+b) - Pnr1.(a+b+l) + Pna1. = 0RDy =

() = ()

= 2235 (N)

RCy = Pnr1 - RDy- Pr2 = -1545 + 2235 + 482 = 1172 (N)

mCx = P2.a - RDx.(a+b)+ Pn1. (a+b+l) = 0

RDx =() = ( ) = 7717 (N)

RCx = -Pn1-P2 + RDx = -(4277+1324)+7717= 2216 (N)

Tnh moment ti tit din nguy him :

Ti tit din b-b : Mue-e = Muy = RCy.a =1172.58,5 =68562 (N.mm)Mux = RCx.a= 2216.58.5 = 129636(N.mm)

Mub-b = 146650 (Nmm)

Mtd = = =149882(N.mm)

Chn ]= 50 N/mm2* ng knh trc ti tit din b-b :

db-b ] = = 31,06 (mm)chn db-b= 40 (mm) d thm phn rnh then v chn trc d gia cng .

* Ti tit din c-c :

Muy = -Rnr1.c+ 0.5 dtb.Pna= -76. 1545+ 0,5.88,2.193= 108908(Nmm)Mux = Pn1 .c= 4277. 76= 325052 (Nmm)


46/46


Mui-i = 342811(Nmm)

[] = 70 N/mm2bng 7-3(TKCTM)

Mx = Mnx - Mgtx = - (Nmm)Mtd = = 379245 (Nmm)ng knh trc ti tit din c-c :

dc-c ] = = 39,83 (mm) ,chn dc-c = 40 (mm)Vy trong trng hp ny nn ta chn li ng knh trc ti tit din b b l 45

(mm) v ti c-c l 40 (mm)

đồ án máy trộn bê tông "hộp giảm tốc 1 cấp"

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