64 Thuyet Minh DAMH CTM

I HC QUC GIA TP H CH MINH - TRNG I HC BCH KHOA KHOA C KH B MN THIT K MY

ooOoo

N MN HC CHI TIT MY

THIT K H THNG DN NG THNG TRN

Sv THC HIN: HUNH HNG LUN MSSV: 205012345 LP; CK05KSTN

Gv HNG DN: NGUYN HU LC

NM 2008

n TKHT truyn ng c kh GVHD: PGS.TS. Nguyn Hu Lc

Sinh vin thc hin: Hunh Hng Lun 1

MC LC

Li ni u2 I. TM HIU H THNG TRUYN NG..3 II. CHN NG C V PHN PHI T S TRUYN.5 III. TNH TON THIT K CC CHI TIT MY...6

1. Tnh ton b truyn xch..6 2. Tnh ton cc b truyn trong hp gim tc8 3. Chn ni trc..12 4. Tnh ton thit k trc v then13 5. Chn ln......21 6. Thit k v hp v cc chi tit ph26 7. Chn du bi trn..28 8. Bng dung sai lp ghp..29

Ti liu tham kho...30



LI NI U

Trong cuc sng hng ngy, chng ta c th bt gp h thng truyn ng

khp ni, c th ni n ng vai tr nht nh trong i sng cng nh trong sn xut. V n thit k h thng truyn ng c kh gip sinh vin chng ta bc u lm quen vi nhng h thng truyn ng ny.

n thit k h thng truyn ng c kh l mt mn hc khng th thiu trong chng trnh o to k s c kh, nhm cung cp cho sinh vin cc kin thc c s v kt cu my. ng thi, mn hc ny cn gip sinh vin h thng ha kin thc cc mn hc nh Nguyn l my, Chi tit my, Sc bn vt liu, V c kh t cho ta mt ci nhn tng quan hn v thit k c kh. Thm vo , trong qu trnh thc hin s gip sinh vin b sung v hon thin cc k nng v AutoCad, iu ny rt cn thit i vi mt k s c kh.

Em xin chn thnh cm n thy Nguyn Hu Lc tn tnh hng dn, cm n cc thy c v bn b trong khoa C kh gip em rt nhiu trong qu trnh thc hin.

Sinh vin thc hin: Hunh Hng Lun



I. TM HIU H THNG TRUYN NG: S h thng dn ng thng trn:

1

2

3

4

5

H thng dn ng thng trn gm:

1- ng c in 3 pha khng ng b 2- Ni trc n hi 3- Hp gim tc bnh rng tr rng nghing hai cp ng trc 4- B truyn xch ng con ln 5- Thng trn

S ti trng:



T

T

t

1

2T

t1 t2 Cc s liu thit k: _ Cng sut trn trc thng trn: P = 8 kW _ S vng quay trn trc thng trn: n = 55 vng/pht _ Quay mt chiu, lm vic 1 ca, ti va p nh _ Thi gian phc v: L = 6 nm (1 nm lm vic 300 ngy, 1 ca lm vic 8 gi) _ Ch ti: T1 = T ; T2 =0,9T t1 =49s ; t2 = 36s c im ca hp gim tc hai cp ng trc: + u im: kch thc theo chiu di nh nn gim trng lng, do c kch thc nh gn hn so vi cc loi hp gim tc hai cp khc. + Nhc im: _ Kh nng ti cp nhanh cha dng ht, v ti trng tc dng vo cp chm ln hn kh nhiu so vi cp nhanh trong khi khong cch trc ca hai cp li bng nhau. _ Hn ch kh nng chn phng n b tr do ch c mt trc u vo v mt trc u ra. _ Kt cu phc tp do c bn trong v hp. _Trc trung gian ln do khong cch gia cc ln. _ Kch thc chiu rng ln.



II. CHN NG C V PHN PHI T S TRUYN: Cng sut tng ng trn trc thng trn:

2i

2i

tdi

T t49 0,9 .36TP P 8 7,67 kW

t 49 36

+ = = =+

Hiu sut chung ca h thng truyn ng: 4

ch br1 br2 x ol = Theo bng 3.3 [1] ta chn:

br1 br2 x ol0,97; 0,93; 0,99 = = = = 4ch 0,97.0,97.0,93.0,99 0,84 = =

Cng sut cn thit ca ng c: td

dcch

P 7,67P 9,13 kW0,84= = =

T s truyn chung: dc

ch 1 2 xct

nu u u un

= =

Da vo ph lc P1.3 [2] ta chn ng c c cng sut Pdc = 11kW vi s vng quay v phn b t s truyn h thng truyn ng nh sau: ng c S vng

quay ng c, (vg/ph)

T s truyn chung, uch

T s truyn hp gim tc, uh

B truyn bnh rng, u1

B truyn bnh rng, u2

B truyn xnh, ux

4A132M2Y3 2907 52,85 16 4 4 3,3 4A132M4Y3 1458 26,51 9,92 3,15 3,15 2,67 4A160S6Y3 970 17,63 6,25 2,5 2,5 2,82 4A160M8Y3 730 13,27 6,25 2,5 2,5 2,12



Ta chn ng c 4A132M4Y3 vi bng c tnh k thut nh sau: Trc Thng s

ng c I II III Cng tc

Cng sut (kW) 9,13 9,03 8,67 8,33 7,67 T s truyn 1 3,15 3,15 2,67 Mmen xon (Nmm) 59802 59147 178830 541167 1331791

S vng quay (vg/ph) 1458 1458 463 147 55 III. TNH TON THIT K CC CHI TIT MY: 1. Tnh ton b truyn xch:

Cc thng s u vo: P1 = 8,33kW; n1 = 147vg/ph; u = 2,67; T = 541167Nmm.

Chn loi xch ng con ln. S rng ca a xch dn:

1z 29 2u 29 2.2,67 23,66= = = chn z1 = 24 rng 2 1z uz 2,67.24 64,08= = = z2 = 64 rng

Cc h s iu kin s dng: K = KrKaKoKdcKbKlv = 1.1.1.1.1.1 = 1 vi Kr = 1: dn ng bng ng c in v ti trng ngoi tc dng ln b truyn tng i m

Ka = 1: khi a = (3050)pc Ko = 1: khi ng ni tm 2 a xch hp vi ng nm ngang mt gc

nh hn 60 Kdc = 1: trc iu chnh c Kb = 1: bi trn nh git Klv = 1: lm vic mt ca

01n

1

n 200K 1,36n 147

= = = n1

z1

z 25K 1,04z 24

= =

Kx = 1: chn xch mt dy



Cng sut tnh ton: n z 1

tx

KK K P 1.1,36.1,04.8,33P 11,78 kWK 1

= = =

Theo bng 5.4 [1], ta chn bc xch pc = 31,75mm. Theo bng 5.2 [1], s vng quay ti hn nth = 600vg/ph nn iu kin n < nth

c tha. Vn tc trung bnh ca xch:

cnzp 147.24.31,75v 1,87 m/s60000 60000

= = = Lc vng c ch:

t1000P 1000.8,33F 4454,54 N

v 1,87= = = Kim nghim bc xch:

1 33c1 1 0 x

P K 8,33.1p 600 600 26z n [p ]K 24.147.29.1

= =

Do bc xch pc = 31,75mm nn iu kin c tha. Chn khong cch trc s b: ca 40p 40.31,75 1270 mm= = = S mt xch:

2 2

1 2 2 1 c

c

2a z z z z p 2.1270 24 64 64 24 31,75X . . 125p 2 2 a 31,75 2 2 1270

+ + = + + = + + =

Chn X = 126 mt xch. Chiu di xch: cL p X 31,75.126 4000,5 mm= = = Tnh chnh xc khong cch trc:

2 21 2 1 2 2 1

cz z z z z za 0,25p X X 8 1285,86 mm

2 2 2 + + = + =

Chn a = 1282mm ( gim khong cch trc (0,0020,004)a ). Theo bng 5.6 [1] vi bc xch pc = 31,75mm ta chn [i] = 16. S ln va p trong 1 giy:

1 1z n 24.147i 1,87 [i] 1615X 15.126

= = = < = Ti trng ph hy: Q = 88,5kN



Lc trn nhnh cng: F1 Ft =4454,54N Lc cng do lc ly tm gy nn: 2 2v mF q v 3,8.1,87 13,29 N= = = Lc cng ban u ca xch: 0 f mF K aq g 6.1,282.3,8.9,81 286,74 N= = =

H s an ton: 3

1 v 0

Q 88,5.10s 18,61 [s] (7,8 9,4)F F F 4454,54 13,29 286,74

= = = > = + + + +

Lc tc dng ln trc: r m tF K F 1,15.4454,54 5122,72 N= = = ng knh a xch:

c 11

p z 31,75.24d 242,55 mm = = = c 2

2p z 31,75.64d 646,81 mm = = =

a1 1 cd d 0,7p 264,78 mm= + = a2 2 cd d 0,7p 669,03 mm= + =

2. Tnh ton cc b truyn trong hp gim tc: a/ Chn vt liu v xc nh ng sut cho php:

Do khng c yu cu g c bit v theo quan im thng nht ha trong thit k, ta chn vt liu 2 cp bnh rng nh nhau.

Chn vt liu la thp 45 c ti ci thin. rn trung bnh bnh dn HB1 = 250 rn trung bnh bnh b dn HB2 = 235

Gii hn mi tip xc v un ca cc bnh rng: OH lim1 12HB 70 2.250 70 570 MPa = + = + = OH lim2 22HB 70 2.235 70 540 MPa = + = + = OFlim1 11,8HB 1,8.250 450 MPa = = = OFlim2 21,8HB 1,8.235 423 MPa = = =

S chu k lm vic c s: 2,4 2,4 7

HO1 1N 30HB 30.250 1,71.10= = = chu k 2,4 2,4 7

HO2 2N 30HB 30.235 1,47.10= = = chu k NFO1 = NFO2 =5.106

S chu k lm vic tng ng:



33 9i

HE1 i imax

T 49 36N 60c n t 60.1.1458.14400 .0,9 1,1.10T 85 85

= = + = chu k 8HE1

HE2NN 3,5.10

u= = chu k

66 9i

FE1 i imax

T 49 36N 60c n t 60.1.1458.14400 .0,9 10T 85 85

= = + = chu k 8FE1

FE2NN 3,17.10

u= = chu k

V NHE > NHO; NFE > NFO nn KHL = KFL =1 ng sut tip cho php:

HLH OH lim

H

0,9K[ ]s

=

H1 570.0,9[ ] 466,36 MPa1,1 = =

H2540.0,9[ ] 441,82 MPa

1,1 = =

( )H H1 H2 H2[ ] 0,45 [ ] [ ] 408,68 MPa [ ] 441,82 MPa = + = < = H[ ] 441,82 MPa =

ng sut un cho php: FL

F OFlimF

K[ ]s

=

F1 450[ ] 257,14 MPa1,75 = =

F2423[ ] 241,71 MPa1,75

= = b/ Tnh ton cp bnh rng cp chm: Cc thng s cho trc: T2 = 178830Nmm; n2 = 463vg/ph; u2 = 3,15

Chn ba2 0,4 = . Khi bd2 ba2 2(u 1) 0,83 = + = . Theo bng 6.4 [1], ta chn H FK 1,03; K 1,05 = = Khong cch trc:

2 H33w 2 2 2 2

ba2 H 2

T K 178830.1,03a 43(u 1) 43(3,15 1) 162,05 mm[ ] u 0,4.441,82 .3,15

= + = + =

Theo tiu chun, ta chn: aw2 = 160mm.



M un rng: mn = (0,010,02)aw2 = 1,63,2 mm Theo tiu chun, ta chn: mn = 3mm.

T iu kin: 8 20 suy ra w 2 w 23

n 2 n 2

2a cos20 2a cos8zm (u 1) m (u 1)

+ + 324,1 z 25,4 Chn z3 = 25 z4 = 25.3,15 = 78,75 chn z4 = 79

Gc nghing rng: 3.25(3,15 1)arccos 13,432.160

+= = T s truyn: 42

3

z 79u 3,16z 25

= = =

Cc thng s hnh hc ch yu ca b truyn bnh rng: ng knh vng chia: 3 n3

z m 25.3d 77,11 mmcos cos13,43= = = ; d4 =243,66mm

ng knh vng nh: na3 3

2md d 83,28 mmcos= + = ; da4 = 249,83mm

ng knh vng chn: nf3 3

2,5md d 69,40 mmcos= = ; df4 = 235,95mm

Khong cch trc: n 3 2w 2 m z (u 1)a 160 mm2cos+= =

Chiu rng vnh rng: b4 = ba2aw2 = 0,4.160 = 64 mm

b3 = b4 + 5 = 64 +5 = 69 mm Vn tc vng bnh rng:

3 2d n .77,11.463v 1,8760000 60000 = = = m/s

Theo bng 6.3 [1], ta chn cp chnh xc 9 vi vgh = 6m/s. Chn h s ti trng ng KHV = 1,03; KFV = 1,1

ZM = 275MPa1/2



tw ttg tg20arctg 20,516

cos cos13,43

= = = = b tarctg(cos .tg ) arctg(cos20,516 .tg13,43 ) 12,606 = = =

bH

tw

2cos 2cos12,606Z 1,724sin2 sin(2.20,516 )

= = =w

bn

b sin 64sin13,43 1,577 1m .3

= = = >

1 1Z 0,7751,665 = = =

vi 3 4

1 11,88 3,2 cos 1,665z z

= + =

w 2w3

2

2a 2.160d 76,92 mmu 1 3,16 1

= = =+ +

Kim nghim bn tip xc:

2 H HV 2M HH

w3 w 2

2T K K (u 1)Z Z Z 422 MPad b u

+= = H H V R xH[ ] [ ]Z Z Z 441,82.1.0,95.1,02 428,12 MPa = = =

H H[ ] < nn iu kin bn tip xc c tha. Kim nghim bn un:

H s dng rng:

F33

13,2Y 3,47 3,998z

= + =

F44

13,2Y 3,47 3,64z

= + =

c tnh so snh bn cc bnh rng: F3

F3

[ ] 257,14 64,32Y 3,998 = =

F4

F4

[ ] 241,71 66,4Y 3,64 = =

Ta kim tra bn un theo bnh dn c bn thp hn. F3 2 F FV

F3 F3w3 w n

2Y T K K111,83 MPa [ ] 257,14 MPa

d b m = = < =



Do bn un c tha. Lc tc dng ln b truyn:

2t3 t4

n 3

2T cos 2.178830.cos13,43F F 4638 Nm z 3.25

= = = = t3 nw

r3 r4F tg 4638.tg20F F 1736 N

cos cos13,43

= = = =

a3 a4 t3F F F tg 4638.tg13,43 1107 N= = = = c/ Tnh ton cp bnh rng cp nhanh:

V y l hp gim tc ng trc nn ta chn cc thng s hnh hc ca cp bnh rng cp nhanh ging nh cp cp chm, ch tr chiu rng vnh rng. Chn ba1 0,25 = . Khi , chiu rng vnh rng ca cp nhanh:

b2 = ba1aw1 = 0,25.160 = 40 mm b1 = b2 + 5 = 40 +5 = 45 mm

Lc tc dng ln b truyn: 1

t1 t2n 1

2T cosF F 1534 Nm z

= = = t1 nw

r1 r2F tgF F 574 N

cos= = =

a1 a2 t1F F F tg 366 N= = = 3. Chn ni trc:

Mmen truyn qua ni trc T = 59802Nmm. Theo ph lc 11.5 [3], ta chn ni trc n hi c:

d = 20mm dc = 10mm D0 = 68mm lc = 19mm dm = 40mm ai c M8 l1 = 15mm z = 6 l2 = 22mm d0 =19mm c = 2mm l0 = 15mm

Chn vt liu l thp 45 vi ng sut un cho php [F] = 70Mpa, ng sut dp gia cht v ng [d] = 3Mpa.

Kim tra bn un: c

F F3 3c 0

KTl 1,45.59802.19 40,38 MPa [ ]0,1d D z 0,1.10 .68.6

= = = <



Kim tra bn dp:

d d0 c 0

2KT 2.1,45.59802 2,83 MPa [ ]zD d l 6.68.10.15

= = = < Do iu kin un v bn dp ca ni trc c tha. 4. Tnh ton thit k trc v then:

Chn vt liu ch to cc trc l thp 45 c b = 600Mpa, ng sut xon cho php [] = 20Mpa.

Theo bng 10.1 [1], chn ng sut un cho php [] = 70Mpa. Xc nh s b ng knh trc theo cng thc:

k3kTd

0,2[ ]= Vi T1 = 59147Nmm; T2 = 178830Nmm; T3 = 541167Nmm ta tnh v chn

s b dng knh cc trc nh sau: d1 = 25mm; d2 = 35mm; d3 = 50mm. Xc nh khong cch gia cc gi v im t lc:

S dng cc bng 10.2, 10.3, 10.4 [2] v cc cng thc 10.10, 10.13 [2] ta xc nh s b cc khong cch nh sau: l12 = -69mm l13 = 45mm l11 = 90mm l22 = 48mm l23 = 190mm l21 = 251mm l32 = 65,5mm l31 = 131mm l33 = 217mm S phn tch lc:



Fnt

F t1

Fa1

F r1

F t2

F r2

Fa2

Fa3

F r3F t3

F t4F r4

F a4

F x

( I )

( II )

( III )

1nt

0

2T 2.59147F 0,2 0,2 348 ND 68

= = = ; Fx = 5123N

Ft1 = Ft2 = 1534N Ft3 = Ft4 = 4638N Fr1 = Fr2 = 574N Fr3 = Fr4 = 1736N Fa1 = Fa2 = 366N Fa3 = Fa4 = 1107N S dng phng trnh mmen v phng trnh hnh chiu ca cc lc trong mt phng zOy v zOx, ta tnh c phn lc ti cc nh sau: Rx10 = 152N Ry10 = 130N Rx11 = 1034N Ry11 = 444N Rx20 = 113N Ry20 = 894N Rx21 = 3217N Ry21 = 1416N Rx30 = 2319N Ry30 = 1309N Rx31 = 2319N Ry31 = 8168N



l12 l11

l13

F nt Rx10 Rx11

Ry10

F r1

F a1F t1 Ry11

19980

46530

24030

59147

12 1013

11

MxNmm

NmmMy

TNmm

20 25 2528



42846863765545

196237

178830

l22

l23

l 21

Rx20

Ry20 Ry21

Rx21

F t2

F r2

F a2

F a3

F r3F t3

20 2223

21

NmmMy

TNmm

MxNmm

35 40 40 35



l32

l31

l33

F a4

F t4F r4

F x

Rx30

Ry30

Ry31Rx31

220639

420086151895

541167

3032

3133

NmmMx

MyNmm

NmmT

50 55 50 45



Xc nh mmen tng ng v ng knh ti cc tit din bng cc cng thc:

2 2x yM M M= +

2 2tdM M 0,75T= +

td3Md

0,1[ ]= Sau t yu cu v bn, lp ghp v cng ngh ta chn ng knh cc

on trc nh bng sau:

Tit din M Mtd d (tnh) d (chn) 12 0 51223 19,4 20 10 24030 56579 20,1 25 13 50638 72028 21,8 28 11 0 0 0 25 20 0 0 0 35 22 43203 160784 28,4 40 23 214406 264490 33,6 40 21 0 0 0 35 30 0 0 0 50 32 267869 539815 42,6 55 31 420086 629379 44,8 50 33 0 468664 40,6 45

Theo yu cu v cng ngh v lp rp, da vo bng 9.10 [2] ta chn then ti cc tit din nh sau:



Tit din d bh t1 t2 12 20 66 3,5 2,8 13 28 66 3,5 2,8 22 40 128 5 3,3 23 40 128 5 3,3 32 55 149 5,5 3,8 33 45 149 5,5 3,8

Kim nghim bn trc:

ng sut un thay i theo chu k i xng , do : m aM0;W

= =

vi 3 2

1 1d bt (d t )W32 2d =

V trc quay mt chiu nn ng sut xon thay i theo chu k mch ng,

do : m a0

T2W

= =

vi 3 2

1 10

d bt (d t )W16 2d =

1 b(0,4 0,5) 270 MPa = = 1 b(0,22 0,25) 150 MPa = = Theo bng 10.8 [1], ta chn K = 1,75; K =1,5 Theo hnh 2.9 [1], tra c cc h s: = 0,05; = 0,02 Theo bng 10.3 [1], ta tra cc h s v H s an ton c tnh theo cng thc:

2 2

s sss s

= +

vi 1a

m

s K

=+

; 1a

m

s K

=+

Trc tha iu kin bn mi khi: s [s] = 2,5



Tit din

d, mm

W, mm3

W0, mm3

a, MPa

m=a, MPa

s s S

12 20 642 1428 0 20,71 0,91 0,89 - 4,25 4,25 10 25 1534 3068 13,15 9,64 0,91 0,89 10,68 9,12 6,94 13 28 1930 4085 26,24 7,24 0,91 0,89 5,35 12,15 4,90 23 40 5364 11648 39,97 7,68 0,88 0,81 3,40 10,43 3,23 32 55 14619 30952 18,32 8,74 0,81 0,76 6,82 8,61 5,35 31 50 12272 24544 34,23 11,02 0,84 0,78 3,79 7,00 3,39 33 45 7611 16557 0 16,34 0,84 0,78 - 4,70 4,70

Kt qu trn cho thy cc tit din nguy him trn 3 trc u m bo an ton

v mi. Kim nghim bn then: Vi ti trng va p nh th: [d] = 130Mpa; [c] = 90Mpa iu kin bn dp v bn ct ca then:

d dt 1

2T [ ]dl (h t )

=

c ct

2T [ ]dl b

= Tit din d, mm bh t1, mm lt, mm T, Nmm d, MPa c, MPa

12 20 66 3,5 25 59147 94,64 39,43 13 28 66 3,5 36 59147 46,94 15,56 22 40 128 5 40 178830 74,51 37,26 23 40 128 5 63 178830 47,31 11,83 32 55 149 5,5 56 541167 100,40 25,10 33 45 149 5,5 63 541167 109,08 27,27

Kt qu trn cho thy tt c cc mi ghp then u m bo bn dp v

bn ct.



5. Chn ln: a/ Trc I:

S b tr cc nh hnh v:

Fr0 F r1

S0 S1

Fa Ti trng hng tm tc dng ln cc :

2 2 2 2r0 x10 y10F R R 152 130 200 N= + = + =

2 2 2 2r1 x11 y11F R R 1034 444 1125 N= + = + =

Lc dc trc: Fa = 366 N Theo ph lc 9.4 [3], ta chn a cn c nh vi k hiu 7205 c C =

24000N, C0 =17500N v gc tip xc = 13,5. Kim nghim kh nng ti ng ca :

Theo bng 11.3 [1], h s ti trng dc trc: e 1,5tg 1,5tg13,5 0,36= = =

Lc dc trc do lc hng tm sinh ra: 0 r0S 0,83eF 0,83.0,36.200 60 N= = = 1 r1S 0,83eF 0,83.0,36.1125 336 N= = =

V S0 < S1 v Fa > S1- S0 do theo bng 11.5 [1], ta xc nh c ti trng dc trc tnh ton: Fa0 = S0 = 60 N Fa1 = S0 + Fa = 60 + 366 = 426 N

H s: K = 1,3 ( bng 11.2 [1] ) Kt = 1 V = 1 ( vng trong quay ) V:



a0

r0

F 60 0,3 e 0,36VF 200

= = = X 1; Y 0 = =

0 r0 a0 tQ (XVF YF )K K 260 N = + = a1

r1

F 426 0,38 e 0,36VF 1125

= = > = X 0,4; Y 0,4cot g 1,666 = = =

1 r1 a1 tQ (XVF YF )K K 1508 N = + = Do , ta chn theo 1 v ti trng tc dng ln hn.

Ti trng tng ng: 0,3m

i i 10/3mE

i

(Q L ) 49 36Q 1508 0,9 . 1449 NL 85 85

= = + =

vi a cn m = 10/3 Kh nng ti ng ca :

0,3 0,3tt EC Q L 1449.(1259,712) 12335 N C 24000 N= = = < =

vi 6 6hL 60nL .10 60.1458.14400.10 1259,712 = = = triu vng

Nh vy, chn m bo kh nng ti ng. Kim nghim kh nng ti tnh:

Theo bng 11.6 [1] vi a cn: X0 = 0,5; Y0 = 0,22cotg = 0,22cotg13,5 = 0,916

t 0 r1 0 a1 r1Q X F Y F 0,5.1125 0,916.426 953 N F= + = + = < Qt = Fr1 = 1125 N C0 = 17500 N

Do , chn m bo kh nng ti tnh. b/ Trc II:

S b tr cc nh hnh v:

Fa3

S1S0

F r1F r0

F a2



Ti trng hng tm tc dng ln cc : 2 2 2 2

r0 x20 y20F R R 113 894 901 N= + = + = 2 2 2 2

r1 x21 y21F R R 3217 1416 3515 N= + = + = Lc dc trc: Fa = 1107 - 366 = 741 N Theo ph lc 9.4 [3], ta chn a cn c nh vi k hiu 7207 c

C = 38000N, C0 = 26000N v gc tip xc = 14. Kim nghim kh nng ti ng ca :

Theo bng 11.3 [1], h s ti trng dc trc: e 1,5tg 1,5tg14 0,37= = =

Lc dc trc do lc hng tm sinh ra: 0 r0S 0,83eF 0,83.0,37.901 277 N= = = 1 r1S 0,83eF 0,83.0,37.3515 1079 N= = =

V S0 < S1 v Fa < S1- S0 do theo bng 11.5 [1], ta xc nh c ti trng dc trc tnh ton: Fa0 = S1 Fa = 1079 741 = 338 N Fa1 = S1 = 1079 N H s: K = 1,3 ( bng 11.2 [1] ) Kt = 1 V = 1 ( vng trong quay )

V: a0

r0

F 338 0,375 e 0,36VF 901

= = > = X 0,4; Y 0,4cot g 1,604 = = =

0 r0 a0 tQ (XVF YF )K K 1173 N = + = a1

r1

F 1079 0,307 e 0,36VF 3515

= = = X 1; Y 0 = =

1 r1 a1 tQ (XVF YF )K K 4570 N = + = Do , ta chn theo 1 v ti trng tc dng ln hn.

Ti trng tng ng:



0,3mi i 10/3

mEi

(Q L ) 49 36Q 4570 0,9 . 4390 NL 85 85

= = + =

vi a cn m = 10/3 Kh nng ti ng ca :

0,3 0,3tt EC Q L 4390.(400,032) 26491 N C 38000 N= = = < =

vi 6 6hL 60nL .10 60.463.14400.10 400,032 = = = triu vng


Theo bng 11.6 [1] vi a cn: X0 = 0,5; Y0 = 0,22cotg = 0,22cotg14 = 0,882

t 0 r1 0 a1 r1Q X F Y F 0,5.3515 0,882.1079 2709 N F= + = + = < Qt = Fr1 = 3515 N C0 = 26000 N

Do , chn m bo kh nng ti tnh. c/ Trc III:

S b tr cc nh hnh v:

Fa

S1S0

F r1F r0

Ti trng hng tm tc dng ln cc :

2 2 2 2r0 x30 y30F R R 2319 1309 2663 N= + = + =

2 2 2 2r1 x31 y31F R R 2319 8168 8491 N= + = + =

Lc dc trc: Fa = 1107 N Theo ph lc 9.4 [3], ta chn bi chn vi k hiu 36210 c C = 43200N,

C0 = 27000N v gc tip xc = 26. Kim nghim kh nng ti ng ca :

Theo bng 11.3 [1], h s ti trng dc trc: e = 0,68 Lc dc trc do lc hng tm sinh ra:



0 r0S eF 0,68.2663 1811 N= = = 1 r1S eF 0,68.8491 5774 N= = =

V S0 < S1 v Fa < 0 do theo bng 11.5 [1], ta xc nh c ti trng dc trc tnh ton: Fa0 = S1 + Fa = 5774 + 1107 = 6881 N Fa1 = S1 = 5774 N H s: K = 1,3 ( bng 11.2 [1] ) Kt = 1 V = 1 ( vng trong quay )

V: a0

r0

F 6881 2,584 e 0,68VF 2663

= = > = X 0,41; Y 0,87 = =

0 r0 a0 tQ (XVF YF )K K 9202 N = + = a1

r1

F 5774 0,674 e 0,68VF 8491

= = > = X 0,41; Y 0,87 = =

1 r1 a1 tQ (XVF YF )K K 11056 N = + = Do , ta chn theo 1 v ti trng tc dng ln hn. Ti trng tng ng:

1/3mi i 3

mEi

(Q L ) 49 36Q 11056 0,9 . 10616 NL 85 85

= = + =

vi bi m = 3 Kh nng ti ng ca :

3 3tt EC Q L 10616. 63,504 42354 N C 43200 N= = = < =

vi 6 6hL 60nL .10 60.147.7200.10 63,504 = = = triu vng


Theo bng 11.6 [1] vi bi chn: X0 = 0,5; Y0 = 0,37

t 0 r1 0 a1 r1Q X F Y F 0,5.8491 0,37.5774 6382 N F= + = + = <



Qt = Fr1 = 8491 N C0 = 27000 N Do , chn m bo kh nng ti tnh.

6. Thit k v hp v cc chi tit ph: a/ V hp: _ Chiu dy thn hp: = 8 mm _ Chiu dy np hp: 1 = 7 mm _ Chiu dy gn tng cng: e = 8 mm _ Bu lng nn: M16 _ Bu lng cnh : M12 _ Bu lng ghp bch np v thn: M10 _ Vt ghp np : M8 _ Vt ghp np ca thm: M6 _ Chiu dy bch thn hp: S3 = 14 mm _ Chiu dy bch np hp: S4 = 13 mm _ B rng bch np v thn: K3 =38 mm _ Chiu dy hp: S1 = 22 mm _ Chiu rng hp: K1 =48 mm _ Khe h gia bnh rng vi thnh trong hp: 10 mm = _ Khe h gia nh bnh rng ln vi y hp: 1 30 mm = _ S lng bu lng nn: z = 4 b/ Vng pht: ngn khng cho bi bm t bn ngoi vo bn trong v ngn du, m chy ra ngoi. c/ Vng chn du: c tc dng khng cho du bi trn bn vo bi, ngn cch v c nh cc bi vi bnh rng. d/ Cht nh v: dng m bo v tr tng i ca np v thn trc v sau khi gia cng cng nh khi lp ghp. e/ Nt thng hi: lm gim p sut v iu ha khng kh bn trong v bn ngoi hp gim tc.



A B C D E G H I K L M N O P Q R S M27 15 30 15 45 36 32 6 4 10 8 22 6 32 18 36 32

f/ Np ca thm: kim tra, quan st cc chi tit my trong hp khi lp ghp v du vo bi trn vo hp.

A B A1 B1 C K R Vt S lng vt 110 60 150 100 130 80 15 M6 4

g/ Que thm du: kim tra mc du trong hp gim tc.



h/ Nt tho du: dng x du c ra ngoi. M16 x 1,5

7. Chn du bi trn:

Theo cng thc 13.6a [1], ta c: 5 2

HV Hbr

10 Hv

= vi rn b mt 250HB 260HV H = 441,82 Mpa v = 1,87 m/s

5

br10 .260.441,82 271,41

1,87

= =

Theo th 13.9 [1], ta chn du bi trn c nht ng hc = 64.10-6 m2/s khi nhit t = 50C.

Theo bng 13.1 [1], ta chn du bi trn ISO VG 68.



8. Bng dung sai lp ghp: _ Bnh rng c lp trn trc theo kiu lp trung gian: H7/k6. _ Vng trong ln lp ln trc theo h thng l, vng ngoi ln lp ln v hp theo h thng trc. _Thng thng, vng trong quay cn vng ngoi ng yn, do vng trong chu ti tun hon cn vng ngoi chu ti cc b. Vng trong c lp c di vi trc, vi min dung sai ca trc: k6. Vng ngoi lp c khe h hoc lp trung gian vi v hp, vi min dung sai ca l trn v hp: H7.

Chi tit Mi lp ES, m EI, m es, m ei, m Bnh rng trc I H7/k6 +21 0 +15 +2 Bnh rng trc II H7/k6 +25 0 +18 +2 Bnh rng trc III H7/k6 +30 0 +21 +2 a cn I trc I k6 +15 +2 a cn I v hp H7 +30 0 a cn II trc II k6 +18 +2 a cn II v hp H7 +30 0 bi chn trc III k6 +18 +2 bi chn v hp H7 +30 0 Ni trc trc I H7/k6 +21 0 +15 +2 a xch trc III H7/k6 +25 0 +18 +2



Ti liu tham kho: [1]. Nguyn Hu Lc, C s thit k my, NXB i hc Quc gia TP. H Ch Minh, 2004. [2]. Trnh Cht, Tnh ton thit k h thng dn ng c kh, Tp 1 v 2, NXB Gio dc, 2002. [3]. Nguyn Hu Lc, Bi tp chi tit my, NXB i hc Quc gia TP. H Ch Minh, 2003. [4]. Ninh c Tn, Dung sai v lp ghp, NXB Gio dc, 2000. [5]. Trn Hu Qu, V k thut c kh, Tp 1 v 2, NXB Gio dc, 2000. [6]. Nguyn Hu Lc, Thit k c kh vi AutoCad Mechanical, NXB TP. H Ch Minh, 2003. [7]. Nguyn Hu Lc, M hnh ha sn phm c kh vi Autodesk Inventor, NXB Khoa hc v k thut, 2007.

64 Thuyet Minh DAMH CTM

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