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1 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh

Mc Lc LI NI U ...........................................................................................................................4

CHNG 1 : .............................................................................................................................6

TNG QUAN V DY CHUYN SN XUT SM LP HIN NAY ..................................6

1.1. S lc v lch s pht trin: ........................................................................................6

1.2. Thc trng v thch thc i vi nghnh sm lp Vit Nam ......................................8

1.3. S lc v quy trnh sn xut lp xe: .......................................................................... 10

1.4. Mc ch ca ti: ................................................................................................... 14

CHNG 2 : ........................................................................................................................... 15

NGUYN LIU V PH GIA................................................................................................ 15

2.1. Nguyn liu: .................................................................................................................. 15

2.1.1.Cao su thin nhin ................................................................................................... 15

2.1.2.Cao su tng hp ....................................................................................................... 15

2.2. Ha cht dng trong cng ngh cao su ........................................................................... 17

2.2.1. Cht n ................................................................................................................. 17

2.2.2. Cht lu ha. .......................................................................................................... 17

2.2.3. Cht xc tin: .......................................................................................................... 18

2.2.4. Cht tr xc tin: .................................................................................................... 18

2.2.5. Cht phng lo: ....................................................................................................... 18

2.2.6. Cht ho do: .......................................................................................................... 18

CHNG 3 ......................................................................................................................... 20

QUY TRNH CNG NGH ................................................................................................ 20

3.1. Cn luyn ...................................................................................................................... 21

3.1.1. Nhit lc: ................................................................................................................ 22

3.1.2. Lc: ........................................................................................................................ 23

3.2. p sut: ......................................................................................................................... 23

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3.2.1. Quy trnh sn xut sm xe my: .............................................................................. 24

3.2.2. Quy trnh p sut sm xe p .................................................................................. 25

3.2.3. Thit b p sut ....................................................................................................... 26

3.3. Thnh hnh .................................................................................................................... 26

3.3.1. Quy trnh thnh hnh sm xe my ............................................................................ 26

3.3.2. Quy trnh hnh thnh sm xe p ............................................................................. 27

3.3.3. Thit bi ................................................................................................................... 28

3.4. Lu ha ......................................................................................................................... 28

3.4.1. Quy trnh lu ha sm xe my v sm xe p c gn van ........................................ 28

3.4.2. Quy trnh lu ha sm xe p gn van ri ............................................................... 29

3.4.3. Thit b ................................................................................................................... 30

3.5. KCS- ng gi-Lu kho ............................................................................................... 31

3.5.1. Quy trnh cng ngh ............................................................................................... 31

CHNG 4 ............................................................................................................................. 32

LA CHON PHNG AN THIT K ................................................................................... 32

4.1. La chn phng n cho cng on ct dn ...................................................................... 32

4.1.1. Phng n 1: Thc hin th cng ( ct dn bng tay) .................................................. 32

4.1.2. Phng n 2: Thc hin bng my. ............................................................................. 33

(La chn phng n truyn ng cho rnh mang c) .......................................................... 33

4.1.2.1. Phng n 1: Truyn ng vt me ai c: ............................................................. 33

4.1.2.2. Phng n 2: Truyn ng bnh rng thanh rng: ................................................ 34

4.1.2.3. Phng n 3: Truyn ng bng kh nn: ............................................................. 36

4.1.3. La chn phng n cho cng on ct dn: ............................................................... 37

4.2. La chn phng n truyn ng cho b Khun my lu ha: ...................................... 38

4.2.1. Truyn ng vt me ai c : ..................................................................................... 38

4.2.2. Dn ng bng trc v tay quay con trt: .................................................................. 41

4.2.3. Dn ng bng xy lanh thy lc: ................................................................................ 42

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4.2.3. Phn tch chn phng n: .......................................................................................... 43

CHNG 5 ............................................................................................................................. 44

THIT K K THUT MY CT-DAN SM ..................................................................... 44

5.1. Thng s u vo: ......................................................................................................... 44

5.1.1 Kch thc sm (rut xe): ........................................................................................ 44

5.1.2. Nhit ct dn sm ............................................................................................ 46

5.1.3.Trng lng cc cm c cu .................................................................................... 47

5.2. M t nguyn l hot ng ca my: ............................................................................. 49

5.3. Thit k mch kh nn: .................................................................................................. 50

5.4. Tnh ton thng s k thut ca cc chi tit ca mch kh nn:....................................... 52

5.4.1. Tnh ton v la chn xi lanh kh nn: ........................................................................ 52

5.4.1.1. Xi lanh nng h cm dao ct: ............................................................................... 52

5.4.1.2. Xi lanh nng h bn ct sm: ................................................................................ 59

5.4.1.3. Xi lanh nng h cm m kp sm trn: ................................................................. 66

5.4.1.4. Xi lanh y cm ngm kp sm trn & di v xi lanh dn sm: .......................... 74

5.4.2.La chn van kh nn: ................................................................................................. 78

5.4.3.La chn van gim p:................................................................................................. 80

5.4.4.La chn my nn kh: ................................................................................................ 81

Chng 6: ................................................................................................................................ 84

THIT K K THUT MAY LU HA .............................................................................. 84

6.1 Yu cu k thut v thng s u vo my lu ha: ........................................................ 84

6.2 Thit k mch thy lc: .................................................................................................. 85

6.2.1 Nguyn l hot ng: ............................................................................................... 85

6.2.2 Tnh ton cc thng s k thut ca tng chi tit. ..................................................... 86

6.3 Tnh chn l hi gia nhit: ............................................................................................ 110

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LI NI U

Nc ta ang trong thi k cng nghip ho hin i ho t nc, cc ngnh cng

nghip ang c nh nc quan tm c bit. Ngnh cng nghip c kh t

c nhng thnh tu quan trng gp phn pht trin cho dt nc. Ngy nay, t

ng ho sn xut v ang pht trin mnh trong cc nh my sn xut va v

ln, v ngy cng c cc xng sn xut nh p dng vo trong dy chuyn sn

xut ca mnh nhm nng cao cht lng cng nh sn lng sn phm.

Cng vi s pht trin ca khoa hc k thut, nhu cu v i sng ca con

ngi ngy cng cao, trong nhu cu sn phm t cao su l rt ln .V vy ngnh

cng ngh cao su gi vai tr rt quan trng trong i sng x hi. V mt trong

nhng lnh vc cng ngh quan trng m chng ta cng quan tm l cng ngh

sn xut sm xe, lp xe bi v chng l nhng sn phm thit yu phc v nhu

cu i li, sn xut ca con ngi. Chng ta cn pht trin ngnh cng ngh ny,

ci tin cng ngh a dng ha sn phm tng bc p ng nhu cu th trng

v cnh tranh trong nc cng nh th gii.

Cc my mc phc v trong dy chuyn sn xut sm lp xe u c nhp

khu t nc ngoi vi chi ph rt cao. m rng nhu cu t ng ho sn xut

trong cc xng sn xut nh l cng nh tit kim chi ph cho cc nh my sn

xut sm lp th vic t nghin cu, ch to cng nh ni a ho dy chuyn sn

xut l rt quan trng.

L sinh vin ngnh C kh Ch to my, chng em c giao nhim v

Nghin cu dy chuyn sn xut sm (rut) xe my v ch to my ct dn v my

lu ho sm xe. Mc ch ca vic nghin cu ti l thit k c my c cht

lng, nng sut cao nhng gi thnh thp phc v nhu cu trong nc.

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Tuy nhin do yu cu v thi gian hn hp, kin thc cn nhiu hn ch, vic

tm ti liu nghin cu ti chc chn cn nhiu thiu st. V vy rt mong c

s ng gp kin ca thy, c ti c hon thin hn.

Chng em xin chn thnh cm n Thy ThS.Trng Quc Thanh cng cc thy,

c gip trong thi gian va qua em hon thnh tt ti ca mnh.

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CHNG 1 :

TNG QUAN V DY CHUYN SN XUT SM

LP HIN NAY

1.1. S lc v lch s pht trin:

Trong lch s pht trin loi ngi, sm lp xe c xem nh l mt pht minh

quan trng, v n c s dng rng ri trong cc lnh vc ca i sng nh

phng tin vn ti, thit b xy dng, cu to cc b phn bn trong ca my mc

Ging nh cc pht minh khc, s xut hin cc bnh xe nh nhng con ln c

pht hin sm t thi k ng cch y 5000 nm, c dng d i chuyn cc

vt nng. Cc bnh xe dng trong cc thit b vn ti c ghi nhn Sumeria

nm 3500 trc cng nguyn, Assyria 3000 nm trc cng nguyn. Loi xe

nga 4 bnh c khp gn vo trc bnh trc iu khin c ghi nhn

khong 1500 trc cng nguyn.

- Loi xe c nga ko c iu chnh dn cho ph hp t tc cao v c

bit l ng dng trong qun s. Cng vi s ra i ca loi bnh xe trn th s

hnh thnh lp xe, ban u l da v ng hay st c gn vo bo v khung

bnh xe lm bng g khi b ph hng.

- S kin quan trng tip theo chc chn l nm 1846 khi Thompson tnh c pht

hin ra mu cao su cha khng kh mang tnh n hi, c gn vo bnh xe t

lm gim lc ko ca chic xe, lm s di chuyn tr nn d dng hn, v gim

ting n. Khi nim ny c nh ngha mt cch hon chnh hn vo nm 1880

loi v xe c bm y kh nn c pht trin v s dng cho loi xe p 3

bnh.

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- Vic khm ph ra s lu ho cao su Charles Goodyear vo nm 1839 cng vi

s pht trin cng nghip Chu u v Bc M lc by gi, v xe pht trin t

vic ban u ch trng cao su ln vi v bao ph cc sm xe bn trong tin ti

loi v composite phc tp hn bao gm si vi, dy thp v cao su.

- S lin kt gia lp v bnh xe ngy cng c hon thin, ban u ch l nh

cc bng vi tm cao su, (1890-1892) ci tin vi vng dy kim loi t hai mp

lp, 1891 ln u tin sm xe c s dng. Trong giai on ny cc b phn cu

to nn lp v sm u hon thin v thit k ph hp vi nhau.

Trong khun kh ca lun vn, chng em ch xin trnh by k hn v Rut xe

v quy trnh sn xut Rut xe.

Rut xe:

- L mt ng cao su dng vng c mt ct hnh xuyn cha kh nn, rut xe c lp

van bm hay x kh. c th o c p sut bn trng, ngi ta lp vo thn

vi p k monometter.

- Rut cha kh nn lm cho v c th n hi tt, gim xc cho xe ng thi gip

v bm cht vo ning xe.

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1.2. Thc trng v thch thc i vi nghnh sm lp Vit Nam

Cc yu t u vo ca ngnh sm lp

Nh ta bit cao su thin nhin l u vo ti quan trng i vi ngnh sn xut

sm lp. Nng sut cao su ca Vit Nam hin xp th 2 th gii, th 5 v sn

lng v th 4 v lng cao su xut khu do vy cc doanh nghip Vit Nam c

li th ln trong vic sn xut cc mt hng ny.

Tuy vy, cao su thin nhin ch l 1 trong nhng yu t u vo ca ngnh. Cn

cc nguyn liu khc nh than en, cao su tng hp, my mc v dy chuyn sn

xut,... Cc doanh nghip nc ta vn phi nhp khu t nc ngoi. C mt

nghch l trong ngnh cao su Vit Nam l: D l nc xut khu cao su ln

trn th gii nhng hng nm, nc ta vn phi nhp khu cao su t 100,000 n

130,000 tn nhm phc v cho ngnh sn xut sm lp trong nc.

Gi cao su v s nh hng n kt qu kinh doanh ca cc DN sn xut sm

lp

Mc d l nc trong top 5 v sn lng xut khu nhng so vi 2 nc ng u

l Thi Lan v Indonesia th sn lng ca Vit Nam c khong cch qu xa nn

ngnh cao su Vit Nam khng ch ng v gi m phi ph thuc vo bin ng

gi th gii.

Hin nay ti Vit Nam c 3 cng ty sn xut sm lp nim yt trn sn l: Cng ty

c phn cao su Min Nam (M: CSM), Cng ty c phn cao su Nng (M:

DRC) v Cng ty c phn cao su Sao Vng (M: SRC)

Gi cao su thin nhin c xu hng tng, khng h tr nhiu cho doanh nghip

sn xut sm lp. Chi ph nguyn vt liu (ch yu l cao su thin nhin v cao su

tng hp) chim khong 70% c cu gi thnh ca cc doanh nghip ngnh sm

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lp. V vy, vic cao su tng gi mnh trong thi gian qua s nh hng mnh n

li nhun ca cc doanh nghip trong ngnh.

Trong 3 thng u nm 2012, gi cao su tng 24%. Gi cao su phn no c h

tr do ngun cung tht cht, khi Thi Lan, Indonesia v Malaysia ang trong ma

kh, ma cy cao su hn ch cho m.

Trin vng ngnh trong thi gian ti

Gi m cao su nguyn liu trn th trng trong nc tng kh mnh trong 20

ngy u thng 5. C th, gi thu mua m cao su t nhin loi 1 ti Bnh Phc

tng t 15.000 /kg trong tun u thng 5 ln ti 18.900 /kg trong tun th 2 ca

thng 5, v sang n ngy 21/5 gim tr li mc 16.500 /kg.

Ngoi ra, t Qu II/2012, sn lng cao su trong nc v th gii s tng dn cho

n cui nm do vo ma khai thc. Vi ngun cung di do, gi cao su c th s

gim nhng kh gim su do mi y Thi Lan chnh thc can thip vo th

trng quc t y tng gi cao su. Thi Lan cho bit cc nh xut khu s mua

cho n khi gi cao su trong nc ln c mc 120 baht/kg, tc 3.800

USD/tn. Hin gi cao su ang quanh mc 3.400 USD/tn. Hn na, Thi Lan

s nng mc tiu gi cao su ln mc 150 bath/kg v s a ra nhiu bin php h

tr hn na nhm y gi ln 180 bath/kg vo nm ti.

Nguyn liu u vo tng gi s lm tng gi cc sn phm sm lp trong thi

gian ti y

Trong ngn hn, nn kinh t trong nc ang gp kh khn nh hng khng

nh n ngnh sn xut sm lp. Ngnh t ang m mc d s dng nhiu

chiu thc khuyn mi nhng thi im hin ti vn cha kch cu c ngi

tiu dng, nhiu th trng xe my trong nc ng bng. Nn kinh t tr tr i

km vi lm pht thp nn ngi tiu dng hin ti s ginh u tin cho cc mt

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hng thit yu thay v mua cc mt hng nh xe my, t. Do trong ngn hn,

ngnh sm lp tam thi c th s chng li.

Tuy nhin trong di hn, khi nn kinh t phc hi, c s h tng nc ta ngy

cng hon thin, mc thu nhp ca ngi dn tng ln tt yu nhu cu v s dng

cc loi phng tin giao thng nh xe my, t s ngy cng gia tng mnh m.

Do vy nhu cu s dng sm lp cho cc phng tin s ngy cng cao, to iu

kin cho ngnh pht trin v tiu th c nhiu sn phm.

1.3. S lc v quy trnh sn xut lp xe:

Hin nay, rut xe lm t nhng hn hp vt liu polyme khc nhau, c gi cao

su thin nhin hoc tng hp.

Cc polyme ny c trn u vi nhau v vi cc cht n, cc cht tr gia cng,

cc cht lu ha theo nhng cng thc b mt ca mi nh sn xut.

Sau khi c hn hp cao su bn thnh phm vi cc t l thnh phn mong

mun, ngi ta cn phi lc sch cc tp cht trnh gy nh hng ti cht

lng v kn kh ca sn phm sau ny.

Cao su sau khi lc sch, c a vo my p trc vt to ra mt ng cao su

di. My p ny lm cao su "nng chy" ri b y qua u my c cu to c

bit to thnh ng, bn trong c phun bt cch ly nhm chng dnh lng ng.

ng cao su nng ny c i tip vo mt h thng lm ngui bng nc trnh

b lu ha do lc ny n c nhit kh cao. Vic lm mt cn gip n nh cu

trc cc phn t polyme trong bn thnh phm.

Cui h thng lm mt, ng cao su c sy kh ri c ct thnh tng on vi

chiu di ty theo quy cch sn phm. Mi on ng s c t l v gn van,

sau c a n my ni tr thnh mt chic rut trn kn.

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Cng on lu ha s cho ra nhng chic rut xe thnh phm, chng c kim

tra kn trc khi ng gi, nhp kho ri a ra th trng.

Hnh .1: t l v gn van

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Hnh .2.1: my ni

Hnh .2.2: cng on ni thnh rut xe trn kn

13


Hnh .3.1: trc khi lu ha

Hnh .3.2: Cng on lu ha c thc hin trn my lu ha

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Hnh .3.3: sau khi ra khi my lu ha

1.4. Mc ch ca ti:

Vi ti nghing cu dy chuyn sn xut sm lp, thit k my ct dn

v my lu ha trong dy chuyn phc v cho nh my C kh KimLongCO.

Hin nay, nh my ang s dng my ct dn v my lu ha trong dy chuyn

sn xut sm lp lu i nn cc loi my trn u xung cp, v vy hot

ng sn xut rt nguy him n tnh mng ca cng nhn. Bn cnh vn ti

chnh, khng gian sn xut khng em li cho cng ty mt s chn la ty

trong vic mua cc loi my trn ang cho bn trn th trng. V vy mc ch

ca ti ny l thit k my ct dn v my lu ha trong dy chuyn sn xut

lp xe quy cch 2.25/2.5-17, 2.75/3-17, 2.25/2.5-16, 2.75/3-14, 3.5/4-10 nng sut

30.000 chic/ thng ph hp vi tnh hnh hin nay ca cng ty KimLongCO.

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CHNG 2 :

NGUYN LIU V PH GIA

2.1. Nguyn liu:

Hin nay x nghip s dng hai loi nguyn liu chnh: cao su thin nhin

v cao su tng hp.Ngun nguyn liu ny qua hn luyn thnh caosu bn

thnh phm c cht n , cht phng lo , cht ha do nhng cha c cht xc

tin v cht lu ha.

2.1.1.Cao su thin nhin

Cao su thin nhin l cao su khng phn cc nn d ha tan trong cc dung

mi h bo , h thm , khng tan trong dung mi phn cc nh Ceton.Tnh chu

nhit km, phn hy nhit 192 C.Khi lng ring ca cao su thin kh

l:0.914kg/cm

2.1.2.Cao su tng hp

Cao su butyl:

Cao su butyl c tung ra th trng nm 1942 ,hin nay c s dng

trong nhiu lnh vc vi nhng yu cu c bit.

Cc nhm cao su Butyl trn th trng l cht ng trng hp gm mt

lng nh isoprene (khong 1-3%) vi isobutylen c xc tc bng AlCl3

ha tan trong clorua metyl.

Cu trc ha hc ca cao su butyl:

-Tnh nng :cao su butyl c tnh bo ha nn y l loi cao su s dng

nhiu trong nhng mc ch ch c bit vi cc tnh cht nh:

* CH2 C

CH3

CH3

H2C C

CH3

CH

H2C *

x

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+Tnh thm kh rt nh. kn kh ca cao su butyl 8 ln tt hn kn

kh ca cao su t nhin.

+so snh kn kh sm xe lm bng cao su butyl v cao su thin

Sm xe p sut nguyn

thu(Psi) p sut b mt (Psi)

1 tun 2 tun 3 tun

Cao su thin nhin 28 04 08 16.5

Cao su butyl 28 0.5 01 2.0

Khi lu ha dung thm nha PF bin tnh lu ha s to sn phm chu

c nhit cao v kn kh .

Tnh khng lo ha do nhit: sao su butyl lu ha vi h thng lu hunh v

xc tin thng c khuynh hng bin mm nu thng xuyn mi trng

c nhit t 300-700oC F.

Cao su Chorobutyl:

Nm 1960 M sn xut ra loi cao su Butyl mi c bin tnh bi 1-2%

Cholor nhm ci thin tnh cht vi mt s cao su c bo ha cao .Cao

su Chorobutyl c ch to bng cch cho mt lung kh chloro sc vo

dung dch butyl lin tc trong dung mi hexan .C mi phn t chorol s

thot ra mt phn t HCL v mt nguyn t chorol s xut hin trn mch

cao su .

V tr cc nguyn t trn mch chloro nh sau :

Lu ha :

Do c s xut hin ca olefin khng bo ha v cc nguyn t chlore rt

hot ng trong mch cao su, c mhiu k thut lu ha loi cao su ny:

-Lu ha bng ZnO hoc ZnCl2.

- Lu ha bng bialkyl.

H2C C

Cl

CH3

H2C

H2C

H2C C

CH3

CH3

H2C C

H2C

CH3

H2C

nCl

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-- Lu ha bng resin.

Tmh nng sn phm:

-Tnh thm kh v thm m thp.

-Tnh bin dng tr cao.

-Khng oxi , khng ozon tt.

-Chng un mi tt.

-Khng ha cht tt.

2.2. Ha cht dng trong cng ngh cao su

2.2.1. Cht n

-Ci thin l tnh sn phm : cng , lc ko c, khng mi mn, khng

nhit, gim co rt

-Ci thin qui trnh cng ngh :d c khun, cn trng, p n

-H gi thnh sn phm .

-Trong x nghip ngi ta thng dng cht n ch yu l than en.

2.2.2. Cht lu ha.

Lu hunh:

Lu hunh l cht mu vng . d= 2.07 , khng mi , khng v , khng tan

trong nc ,t tan trong cn, eter, glycerin ,tan tt trong Cabon di sulfua, khi

ch st pht sinh ra in tch m. dn in v dn nhit km. T0nc = 1190

C.

Tc dng ca lu hunh :

Lu hunh s dng lm cht lu ha cho cao su thin nhin v cao su tng

hp.

Lu hunh c th tc dng vo cc lin kt i to thnh mng li khng

gian ba chiu thng qua cu ni Sulfua . Lu hunh c hai dng khc nhau

ph thuc vo s sp xp nguyn t: Lu hunh ha tan v lu hunh

khng ha tan . s dng lu hunh ha tan , sau khi lu ha lu hunh t do

c th phun ra b mt gy ra hin tng phun sng. Lu hunh khng ho

tan l loi lu hunh ch phn tn m khng ho tan vo hn hp cao su.

Nn c th hn ch c hin tng phun sng. iu cn ch l khi s

dng lu hunh khng tan th nhit khi cn phi di 100oC, v nhit

ny tr ln lu hunh khng tan s chuyn sang dng lu hunh ho tan.

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Lng dng:

Cao su lu ho mm: dng 0,5-3% so vi trng lng cao su v c s

dng cht xc tin. C th s dng ln ti 10% sn phm cng ln.

Cao su lu ho bn cng: t 10-25% so vi trng lng cao su, c

cht xc tin t s dng lu hunh ny bi sn phm cht lng km.

Cao su cng ebonic: t 25-60%, thn trng d gy lu ho sm.

2.2.3. Cht xc tin:

Cht xc tin c thm vo hn hp cao su hot ho cht lu ho

lm tng tc phn ng, t rt ngn thi gian lu ho, tng tnh nng

c l v h gi thnh sn phm.

Cc cht xc tin s dng lc u l cc hp cht v c nh PbCO3,

Ca(OH)2, PbO v ZnO dng kim. Tuy nhin hiu qu ca chng thp v

chng c thay th bng cc cht xc tin hu c.

2.2.4. Cht tr xc tin:

Cc cht tr xc tin v cc cht xc tin to phc cht c nhim v

lu ho lu hunh v lm tng tc lu ho, ci thin c tnh nng sn

phm, trong ZnO l cht tr xc tin quan trng nht v c s dng

nhiu nht.

2.2.5. Cht phng lo:

Trong thi gian tn tr hay ch bin, mt s loi cao su b hu hoi

hay b bin cht, mt phn l do nh sng, nhit , v mt s kim loi c

hi, nhng quan trng nht l khi lu ho. S lo ho ca cao su biu hin

di nhiu hnh thc khc nhau: bin mu, xut hin cc vt nt, bin cng,

chy nho nn tnh nng c l cng s gim.

Do , qu trnh to sn phm, ta cn phng lo lng s dng 1- 2

% so vi cao su v tu thuc vo mc ch s dng m ta dng cht khng

lo ho ring bit i tc vi nhng tc nhn lo ho.

2.2.6. Cht ho do:

Khi cao su c s luyn bng my mc, cc phn t c ct mch

bng Oxy v tp ra gc t do trn dy phn t. Cht ho do xc tc gn

Oxy thi thc s ct c mch lm thi gian s luyn c rt ngn do

gim tiu

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ha nng lng. Trnh nhit ni sinh qa nhiu lm cao su t lu ho.

Ngoi ra cht ho do khng lm nh hng n tnh nng c l ca sn

phm.

Cht ho do c s dng nhm mc ch lm trng n hn hp,

gim lc ht gia cc phn t lm hn hp mm mi, to iu kin cho cc

cht ph gia phn tn u trong hn hp.

20


CHNG 3

QUY TRNH CNG NGH

S TNG QUT QUI TRNH CNG NGH SN XUT SM

XE

-

Khng t

Khng t

Khng t

p lc

Cao su BTP

Cn luyn

p sut

Thnh hnh

Lu ho

Kim tra

Kim tra

Kim tra

t

t

t

Hi liu

KCS-BB

Lu kho

Khng t Ph phm

21


3.1. Cn luyn

L qu trnh gia nhit cho cao su t do cn thit, ng thi

lm cho ho cht phn tn u trong cao su.

Cn luyn cao su l cng on ht sc quan trng, n c nh hng

trc tip n cc cng on k tip nh p sut, ct ni, thnh hnh, lu ho Gy

nh hng ln n cht lng sn phm. n pha ch tt, nhng qu trnh cn

luyn khng tt, khng ph hp th cao su cng nh cc ho cht s khng kt hp

tt, do khng pht huy ht hiu qu ca n cng ngh.

Cc yu t nh hng n qu trnh cn luyn:

Tnh cht ca cao su bn thnh phm.

Nhit : y l yu t rt quan trng, nu nhit qu cao s lm

cho cao su t lu ho trn my, ngc li nu nhit qu thp th

qu trnh luyn s chm v kh t do mong mun.

Thi gian: nu luyn qu lu c th lm cho cao su qu mm do dn

n vic lm gim mt s tnh cht c l, nu luyn khng thi

gian s khng t c do mong mun.

Thit b: lin quan n tc trc cn, lng ca trc, h thng

nc gii nhit.

Con ngi: qu trnh ct o dao v tay ngh ca ngi cng nhn.

QUY TRNH

CAO SU BTP

NHIT LOC

NHIT THM

HO CHT

CAN RA BNG

LOC

22


3.1.1. Nhit lc:

3.1.1.1. Quy trnh:

Cao su bn thnh phm c cho vo my nhit luyn, di tc dng

nhit c hc cao su bt u chuyn t trng thi ngui cng sang trng thi nng

v t do mong mun. Khi khi cao su do bt u m trc, cng nhn s

dng dao ct o khi cao su c cn u hn. Khi cao su ln mt u th

ngi cng nhn s ly cao su ra thnh tng cun v chuyn sang cng on sau.

23


Qu trnh luyn c tin hnh 10 12 pht, my hot ng khng

qu 75oC. Trong qu trnh cn luyn c h thng nc gii nhit cho vo lin tc

trong trc cn n nh nhit .

3.1.1.2. Thit b:

3.1.2. Lc:

Cao su khi nhit luyn c xut ra dng cun v c chuyn sang cng

on lc. Cun cao su s c cho vo phu nhp liu, i qua trc cn v qua h

thng li lc loi b tp cht. Sn phm thu c l nhng si cao su c ct

thnh b v cn. Qu trnh lc nhm loi b cc tp cht cn st li trong cao su.

y l qu trnh luyn h, ngoi ra cn c qu trnh luyn kn. u im ca qu

trnh luyn kn l c th to ra sn phm theo n ca khch hng, tuy nhin n b

khng ch bi nhit v qu trnh luyn kn xy nhit cao ( khong 165oC)

s lm cho cao su b lu ho.

3.2. p sut:

y l phng php hnh thnh BTP thng c dng nhiu nht, p sut

c p dng trong cng ngh cao su v nhiu nguyn nhn sau:

Nhiu tit din phc tp ca sn phm khng cho php dng khun p

to hnh v gi thnh ca cc khun ph hp rt cao.

p sut l phng php duy nht c nhng chi tit di so vi tit din.

24


3.2.1. Quy trnh sn xut sm xe my:

Quy trnh:

Cao su dng bng c cho vo ming phu. ty vo yu cu sn phm m

ta chn loi u to hnh. Phi sm sau khi p ra khoi ming theo bng ti qua h

thng ch k mc k ch cho sm. My p sut c phu cha bt TALC c

phun vo trong n chng dnh t bng trong. Phi c n nh bng bng ti

ti cc vi phun nc trn. Mt di phi s i qua dung dch bt TALC, mt

trn c thi sch nc bng cc ng thi kh chun b cho qu trnh ng

mc v ghi m phi. Tip theo, phi sm c ct v a vo cng on c l,

dn van. Lc ny, mt trn phi s c ph bt TALC dng dung dch. Ngi

cng nhn s tin hnh kim tra cc thng s k thut theo tiu chun nu phi t

yu cu s c chuyn ln xe a n b phn ct ni.

BTP DNG

BNG

PHU

CT

BNG TI N NH

C L, DN VAN

KIM TRA

PHUN BT TALC

NG MC

HON TT

25


3.2.2. Quy trnh p sut sm xe p

Cao su dng bng s c a vo ming phu ca my p sut. Cao su s

c n bng trc vt n qua u to hnh. ng thi bt TALC v kh s

c thi vo phi thng qua n to phng cho phi. Sau khi ra khi my p

sut cao su to thnh phi dng ng. Phi ny c lm ngui bng h thng

mng nc gii nhit. Sau khi lm ngui phi s c ct bng dao c lp trnh

theo thng s thch hp.

CAO SU BNG

MY P SUT

PHI

LM NGUI

KIM TRA

HON THNH

26


3.2.3. Thit b p sut

Hnh v

3.3. Thnh hnh

Cn phi khng nh y l qu trnh gia cng ch khng phi l qu trnh

thc hin s lin kt ha hc gia cc mch phn t cao su. Qu trnh ny nhm

ni hai u phi sm li vi nhau.

3.3.1. Quy trnh thnh hnh sm xe my

Quy trnh cng ngh

Phi sm c a vo t khu vc p sut sang, cng nhn s t ln

bn v ct theo kch tht quy nh, sau chuyn sang my ni u sm. Phi

sm sau khi ct s c a vo ngm kp dng hai tay nhn hai nt khi ng

cho my hot ng. Dao ct s i t trn xung ct phn b i ri s di chuyn ln

trn ht thng kp thc hin qu trnh ni. Khi sm ni xong ngm kp tch

PHI

I CT

CT NI

27


ra, cng nhn ly sm ra khi my, dng tay bm hai mp vai ca sm cho cht

trnh hin tng mi ni b h, sau xp ln bn chuyn sang giai on lu

ha.

3.3.2. Quy trnh hnh thnh sm xe p

Quy trnh cng ngh:

Phi sm t khu vc p sut c a ln bn ct theo kch thc quy

nh. Sau c l ri a sang khu ni u sm. Sau khi ni phi c lu

trong mt khong thi gian. K tip, ngi cng nhn qut xng v ch xung

quanh l c c, qut keo ln ch kh ri gin ym. Sau dng tay c nh

van vo phi sm ri dng trc c con ln ch ln ym van van bm cht vo

phi sm. Cui cng chuyn ln bng ti qua cng on lu ha.

PHI

O, C

CT NI

DN YM

28


3.3.3. Thit bi

Hnh v

3.4. Lu ha

Lu ha l giai on cui cng ca cng ngh gia cng cao su. Lu ha

nhm to cu ni lu hunh gia cc mch cao su lm tng tnh nng c l p

ng yu cu ca sn phm. Trong qu trnh lu ha th tnh nng mm do, chy

nht ca cao su gim, tnh n hi ca cao su tng ln.

3.4.1. Quy trnh lu ha sm xe my v sm xe p c gn van

NH HNH NG SM

LU HA

LY SN PHM RA

29


Quy trnh

u tin cng nhn nhn phi sm t khu kt ni, kim tra ngoi quan sn phm,

mi ni, van Sau phi c bm nh hnh, dng sp bp kn li u van, ri

sau gn phi vo khun, qu trnh lu ha s din ra t ng, sau thi gian lu

ha l 2,5 pht th khun s t ng m ra v cng nhn ly sn phm ra.

3.4.2. Quy trnh lu ha sm xe p gn van ri

Quy trnh

u tin cng nhn nhn phi t khu ct ni, kim tra ngoi quan, mi ni

ri gn van gi vo, sau gn phi vo khun sao cho van gi khp vi . Kh

nn s bm nh hnh cho phi, tip theo khun s ng li v qu trnh lu ha s

din ra t ng. Sau thi gian 2,15 giy th khun m ra, cng nhn ly sn phm

ra thu hi van gi ri a sm qua bng ti chuyn qua giai on k tip.

GN VAN GI

GN VO KHUN

BM NH HNH

LU HA

LY SN PHM

30


3.4.3. Thit b

Hnh v

31


3.5. KCS- ng gi-Lu kho

3.5.1. Quy trnh cng ngh

Quy trnh

Sau khi lu ha xong, sm theo bng ti i qua h thng ti Silicol t ng

(i vi xe p th khng c cng on ny). Tip theo sm s c xit c, ht

chn khng, gn ty van, kim tra ngoi quan sn phm nu t th ng du chnh

phm v ng gi theo quy nh ca tng loi sm. Hon tt tt c cng on ny

sm s c lu kho ch phn phi. i vi sm xe p kim tra trc ri mi

xit c, ht chn khng, gn ty van. i vi sm xe my xit c, ht chn khng,

gn ty van ri mi kim tra.

SN PHM SAU KHI

LU HA

TI SILICOL

GN TY VAN, XIT C

HT CHN KHNG

NG GI

KIM TRA

NGOI QUAN

LU KHO

32


CHNG 4

LA CHON PHNG AN THIT K

4.1. La chn phng n cho cng on ct dn

Cng on ct dn l 1 cng on rt quan trng trong dy chuyn sn xut sm

(rut) xe. N nh hng ln n cht lng cng nh nng sut ca sn phm.

4.1.1. Phng n 1: Thc hin th cng ( ct dn bng tay)

T khi t ng ho sn xut cn cha pht trin mnh, cc xng sn xut

nh vn thc hin cng on ct v dn sm bng tay. Cc on sm c ct

thnh tng on vi chiu di xc nh trc, sau 2 mp ngoi cng ca on

sm c ct li cho phng bng dao v bn k. Sau khi c ct, 2 mp sm c

gia nhit n nhit cn thit v c t vo khun dn li vi nhau.

u im:

+ Khng tn nhiu tin u t my mc thit b ban u.

Nhc im:

+ Cht lng sn phm ko cao, ko ng u.

+ Nng sut thp.

+ Tn nhiu nhn cng nu mun nng cao sn lng.

33


4.1.2. Phng n 2: Thc hin bng my.

(La chn phng n truyn ng cho rnh mang c)

4.1.2.1. Phng n 1: Truyn ng vt me ai c:

a. S nguyn l

b. Nguyn l hot ng

C cu truyn ng vt me ai c lm vic theo nguyn l n khp ca cp ren (

gia ren trong ai c vi ren ngoi trn vt me) bin chuyn ng quay ca

ng c thnh chuyn ng tnh tin ca bn my hay bng trt di ng .

B truyn c t s truyn cao v c th t hm, do b truyn s dng truyn

ti trng trong my nng, my p vt, trong c c cu iu khin: bn dao, bn

my, trong cc c cu iu khin chuyn ng cho ngi my, my iu khin s,

trong cac c cu hiu chnh ca dng c o.

34


c. u Nhc im:

u im:

+ Kt cu n gin, nh gn, d ch to

+ Chuyn ng chm vi chnh xc cao

+ Kh nng ti ln, tin cy cao

+ Lm vic m, khng n

Nhc im:

+ Tc khng cao.

+ Ma st ln nn ren mn nhanh

+ Hiu sut thp

4.1.2.2. Phng n 2: Truyn ng bnh rng thanh rng:

a. S nguyn l:

Thanh rang

Bnh rang

Rnh truot mang c

35


b. Nguyn l hot ng

S dng c cu truyn ng bnh rng thanh rng bin chuyn ng quay ca

ng c thnh chuyn ng tnh tin ca bn my hay bng trt di ng . y l

phng php truyn ng n gin. Bn my hay bng trt di ng c gn

cng vi thanh rng, s di chuyn tnh tin theo rnh mang c khi ng c quay.

c. u Nhc im:

u im:

+ Kch thc tng i nh gn, kh nng ti ln

+ Hiu sut truyn ng cao, t s truyn n nh.

+ Truyn ng tt trong phm vi cng sut.

Nhc im:

+ Ch to tng i phc tp

+ i hi ch to v lp rp vi chnh xc cao.

+ C nhiu ting n khi vn tc ln

36


4.1.2.3. Phng n 3: Truyn ng bng kh nn:

a. S nguyn l

Rnh truot mang cPiston

37


b. Nguyn l hot ng

S dng h thng kh nn thng qua cc van v pittng kh nn truyn chuyn

ng cho cc c cu. y l phng php c s dng kh rng ri trong cc

my mc trong dy chuyn sn xut v c th cho lc tc dng ln m kch thc

vn nh gn v kh nng lp t d dng.

c. u Nhc im:

u im:

+ Kh nng truyn ng vi cng sut ln, p sut cao.

+ Tc truyn ng cao

+C cu n gin, kch thc nh gn

+ Lp t d dng

+ Phng nga qu ti bng van an ton

Nhc im:

+ Do i hi an ton cao nn gi thnh thit b kh cao

+ Dng kh nn thot ra ng dn kh gy ra ting n

4.1.3. La chn phng n cho cng on ct dn:

p ng cho nhu cu t ng ho sn xut trong cc xng sn xut nh

nhm tng nng sut, tng cht lng, h gi thnh sn phm, chng em chn

phng n thc hin cng on ct dn bng my.

La chn phng n thc hin cng on ct dn bng my nn ta la chn

phng n truyn ng cho my:

Da vo u nhc im ca 3 phng n truyn ng trn, v da vo yu

cu ca my, chng em la chn phng n truyn ng bng kh nn do my ko

yu cu v chnh xc cao v tr khi bn my di chuyn, cn kch thc nh gn

cho lc tc dng ln, thi gian p ng nhanh, d dng lp t, ko i hi ch to

cc chi tit phc tp.

38


4.2. La chn phng n truyn ng cho b Khun my lu ha:

4.2.1. Truyn ng vt me ai c :

a. S nguyn l:

b. Nguyn l hot ng:

ng qua cc b truyn trung gian (ai hoc xch, ni trc,) dn ng cho cp

bnh rng tr nh trn hnh, lng trong bnh b ng v trc c cu di chuyn

ca tht trn c ch to theo kiu vt me- ai c. Khi ng c quay c cu vt

me ai c ny s khin tht trn di chuyn ln xung trong qu trnh lu ha.

y c thm ai c an ton s tng thm tnh t hm cho phng php ny.

39


C cu vt me-ai c lm vic theo nguyn l n khp ca cp ren (gia ren trong

trn ai c vi ren ngoi trn vt me) bin i chuyn ng quay thnh tnh

tin.

c. Cc u im chnh:

- Kt cu n gin, nh gn v d ch to; kh nng ti ln; tin cy cao; lm

vic m v khng n; li nhiu v lc; c th chuyn ng chm vi chnh xc

cao.

d. Tuy nhin c cc Nhc im: do ma st ln nn ren mn nhanh; hiu sut

thp.

e. Phm vi s dng: B truyn c t s truyn cao v c th t hm, do b

truyn s dng truyn ti trng: trong con i tay (), my nng vi h thng c

in (), my p vt, trong cc c cu iu khin, bn dao, bn my, trong cc c

cu truyn ng cho ngi my, my iu khin s hoc s dng truyn

chuyn ng trong cc c cu hiu chnh ca dng c o.

40


41


4.2.2. Dn ng bng trc v tay quay con trt:

a.S nguyn l:

b. Nguyn l hot ng:

Trc quay c dn ng bng ng c v cc c cu trung gian s bin chuyn

ng quay ca tay quay thnh chuyn ng tnh tin ca con trt m lc ny l

b ca khun di v lm cho khun ny tnh tin ln xung, ghp vi cc

khun khc trong qu trnh lu ha.

c.u im:

- Kh nng truyn lc ln.

- Cu to n gin, cng ngh ch to c cu loi ny tng i hon ho =>

d m bo chnh xc yu cu.

- Khng cn bin php bo ton khp

- C th d dng thay i kch thc ng gia cc khu.

d.Nhc im:

- Sai s tch ly trong qu trnh ch to ln

- D lp rp sai quy lut chuyn ng dn n t hm.

42


4.2.3. Dn ng bng xy lanh thy lc:

a.S nguyn l:

b.Nguyn l hot ng:

Qua mt thng thy lc n gin nh bm du, h thng cc van th s to cho

piston truyn ng cc chuyn ng ca n v truyn chuyn ng thnh

chuyn ng tnh tin ln xung ca b ko theo khun di di ng ln

xung, tch ghp vi cc khun cn li trong qu trnh lu ha

c.u im:

- C th b tr cc linh kin thy lc mt cch hp l lm cho h thng nh

gn v thm m.

- C kh nng to lc ln

- An ton

d.Nhc im:

- i hi cc linh kin phi ch to chnh xc cao

- nhy thp, d nhim bn do r r du.

43


.

4.2.3. Phn tch chn phng n:

Nh vy vi yu cu i vi my cn ch to, qua thc tin v nghin cu 3

phng n ta thy c 3 u t yu cu.

Phng n truyn ng bng xy lanh thy lc kt cu n gin, d t ng

ha hon ton, c thm u im ch n, thch hp vi h thng gia nhit bng hi

trong qu trnh lu ha, cc linh kin nh van, ng, d dng tm mua c, an

ton.

V vy trong khun kh lun vn ny ta s chn v tm hiu thit k phng

n truyn ng cho my lu ha bng thy.

44


CHNG 5

THIT K K THUT MAY CT-DAN SM

5.1. Thng s u vo:

5.1.1 Kch thc sm (rut xe):

Hin nay trn th trng c rt nhiu loi xe my ca cc hng khc

nhau, nhng tin cho qu trnh thay th, sa cha khi gp s c, lp xe

(v xe) v sm xe (rut xe) c tiu chun ho theo mt s kch thc

nht nh.

ngha kch thc lp v sm xe:

+ Lp xe:

x y

b

Hnh chiu v mt ct ngang lp xe

Cc loi lp xe trn th trng u c kch thc theo dng: b/c x

Trong : b l b rng lp tip xc vi mt ng n v mm

y l cao ca lp, y = b * c% n v mm

x l ng knh mp trong ca lp n v inch

45


V d: trn lp xe ghi 70/90 17 th:

B rng lp tip xc vi mt ng l 70mm

Chiu cao lp l 70mm * 90% = 63mm

ng knh mp trong lp l 17 inch

+ Sm xe:

Cc thng s ghi trn sm xe:

46


x a

vi sm xe th thng s c ghi theo dng a/b x

V d: trn sm xe ghi 2.25/2.5 - 17 th:

Sm s dng cho lp 2.25 hoc 2.5 inch v c ng knh 17

inch

Mt s loi sm xe thng dng trn th trng m dy chuyn c th sn sut

c:

2.25/2.5 17

2.75/3.00 17

2.25/ 2.5 16

2.75/3.00 14

3.50/4.00 10

5.1.2. Nhit ct dn sm

t c nng sut cao trong qu trnh sn sut, 2 u on ng

cao su c nung mm n nhit khong 320-330 oF ri c ghp

ni li vi nhau .

47


5.1.3.Trng lng cc cm c cu

Trong qu trnh my lm vic, cc cm c cu trt trn cc rnh

mang c nh lc y ca piston kh nn.

a. Cm dao ct sm:

Tng khi lng cn piston phi chu trong qu trnh nng h cm

dao ct l khong 11,4 kg (phn mu trn hnh)

b. Cm ngm kp sm trn:

Tng khi lng cn piston phi chu trong qu trnh nng h cm

ngm kp

c. Cm ngm kp sm trn & di :

48


Tng khi lng mi bn ca cm ngm kp sm di khong 52,65

Kg

Tng khi lng ca cm bn ct sm khong 15,67 Kg

49


5.2. M t nguyn l hot ng ca my:

Cui chu trnh lm vic c, sau khi cm ngm kp sm bn phi

c ko ra, bn ct sm c nng ln v 2 m ca cm ngm kp sm

di c xi lanh y t st vo bn ct sm. Bt u 1 chu trnh lm

vic mi, 2 u sm c t vo 2 ngm kp sm di sao cho mp

ngoi sm cch mp ngoi m kp sm di khong 5mm ( ct b

phn li lm 2 u sm trc khi dn ni li). Sau khi nt Start c

bm, 2 m kp sm trn i xung gi 2 u sm, sau dao ct i xung

v c gi ti v tr cui trong vng 3 giy truyn nhit cho 2 u

sm (dao ct c gia nhit nh b in tr). Sau khi 2 u sm c ct

phng v gia nhit, 2 cm kp sm c xi lanh ko ra; lc , 1 lung

hi c thi nhanh (khong 1/4s) vo mp trong ca 2 li dao y 2

phn u sm tha ra ngoi. Sau khi dao ct c nng ln v bn ct

c h xung cng lc, cm kp sm bn phi c xi lanh y vo, 2

u sm p st vo nhau v c gi trong vng 3 giy. Sau khi dn

xong, ngm kp sm trn c xi lanh ko ln, cm kp sm bn phi

c ko ra. Bn ct sm c y ln v 2 m ca cm ngm kp sm

di c xi lanh y t st vo bn ct sm chun b cho 1 chu trnh

lm vic mi.

50


5.3. Thit k mch kh nn:

T nguyn l hot ng ca my, s dng b tun t tch hp

vi s GRAFCET

Th t tn cc xi-lanh:

A : xi lanh nng h 2 m kp sm trn

B : xi lanh nng h dao ct

C : xi lanh y 2 bn trt

D : xi lanh nng h bn ct sm

E : xi lanh dn sm

1 A+

2

3

4

5

6

7

8

9

B+

C-

B-

E+

A-

E-

D-

C+

D+

a1

t1/ 2/ 3s

c0

b0 . d1

t3/ 5/ 3s

a0

e0

d0

c1 . s

1 2 3 4 5 6 7 8 9

A+ B+ C- B- D+ E+ A- E- D- C+

A

P

R

B

T1 T3&a1

t1

c0

b0 d1

t3

a0 e0 d0 c1

T1 =3s T3 =3s

&

s

K+

K-

t2/ 4/ 14s

10

K+ K-

T2

t2

T2 =1/ 4s

10

A

B

T ta thit k c mch kh nn tng qut ca my, s dng xi

lanh kh nn v 2 loi van solenoid chnh l 2/2 v 5/2.

51


R

P

S

A

B

B-

B+

R

P

S

A

B

A-

A+

R

P

S

A

B

D-

D+

R

P

S

A

B

E-

E+

R

P

S

A

B

C-

C+

P A

K-

K+

B

A A

C CE

D

52


5.4. Tnh ton thng s k thut ca cc chi tit ca mch kh nn:

Chn p sut u vo ca h thng l 8bar, do c tn tht trong

mch kh nn khong 20% nn p sut tc dng ln xi lanh cn khong

5,6 bar

5.4.1. Tnh ton v la chn xi lanh kh nn:

Cc xi lanh c tnh ton cc thng s cn thit v c chn

mua trong catalog ca hng JELPC

(http://www.jelpc.com/sc---su-series-standard-cylinder.html)

5.4.1.1. Xi lanh nng h cm dao ct:

53


Trong qu trnh thc hin cng on ct sm, dao c gia nhit

ln n nhit 165oC, nn lc ct cn thit ch khong 2kgf/cm2 ~ khong

1,962 bar. Theo mch kh nn, p sut trong xi lanh ct lc lm vic l

5,6bar

Xi lanh piston lm t thp c c [] = 80100 MPa.

Tng t nh xi lanh - piston nng h cm m kp, cm dao ct,

piston lin kt cng vi cm dao, nn piston s chu ti bi tc dng ca

mmen do trng tm cm dao ct khng trng vi ng tm ca trc

piston. iu ny c th dn n s mi mn nhanh ng dn hng v lm

hng m kn.

Cc xi lanh thng c ch to t thp Cacbon 45 hoc 60, b mt

ca chng c ti v nh bng cn thn ( nhm b mt khng qu 0.63

v chnh xc tng ng cp 2 khi lp vo ng dn hng). Cn piston

thng c ch to t thp hp kim crm mlipden, cng b mt

cng tc ca piston bng 4860HRC.

Cm dao ct trt ln-xung dc theo rnh mang c thng ng. Do

cn piston chu lc momen do trng tm cm m kp ko trng ng

tm cn piston nn lc ma st trong trng hp ny tng i nh, tin

cho qu trnh tnh ton c th b qua

T p sut lm vic ta suy ra cc thng s s b ca xi lanh piston

theo mi quan h:

Cm dao ct c trng lng P = 11,4 * 9.81 =111,83 N

3 25111,83

0,2.105,6 10

PA m

p

34 4 0,2.10

0,016 lim3,14

cx

AD m

ng knh xi lanh cn thit : D =16mm

54


Hnh trnh cn thit ca xi lanh: trong qu trnh my hot ng, dao

ct di chuyn ln xung 1 on 145mm.

55


Theo kt qu tnh ton s b kch thc xi lanh v theo catalog ca

nh sn sut, ta chn xi lanh c m sn phm SC32x150 c:

ng knh piston : 32mm

56


Hnh trnh piston : 150mm

ng knh cn piston : 12mm

p sut lm vic t 1-9kgf/cm2 (0,981 8,829 bar)

V piston lin kt cng vi cm dao ct, nn piston s chu ti bi tc

dng ca mmen do trng tm cm dao ct khng trng vi ng tm ca

trc piston. Do ta cn kim tra li bn ca cn piston.

S dng phn mm Autodesk Inventor 2011 tm trng tm ca

cm dao ct. V tr t lc v trng tm ca cm dao ct :

G : trng tm ca cm dao ct

A : v tr t piston

A

G

62.1

18

Hnh chiu bng ca cm dao ct ( phn i ng)

57


A

G

62.11812

0.51

8F

P

Hnh chiu cnh ca cm dao ct ( phn i ng)

Khong cch on AG:

2 262,118 120,518 135,58AGL mm

120,518tan 1,94

62,118

62,73o

Momen un tc dng ln u cn piston :

. 111,83.cos .135,58 6946,95AGM P L Nmm

Phn tch lc tc dng ln trc piston v biu momen un:

58


M

A BC

A B C

RA RB

20 162

6946,95Nmm

Kim tra li ng knh trc theo cng thc:

3

0,1[ ]

tdMd

Vi tdM = M

3 36946,95

8,850,1[ ] 0,1[100]

tdMd mm

Vy piston chn tho mn yu cu

59


5.4.1.2. Xi lanh nng h bn ct sm:

F

P

Trong qu trnh lm vic ca my, bn ct sm trn c tc dng k

sm v lm im t cho dao trong qu trnh ct. Khi bn ct sm i ln, p

sut trong xi lanh khong 5,6 bar

Xi lanh lm t thp c c [] = 80100 MPa.

V piston lin kt cng vi cm nng h bn ct, nn piston s chu

ti bi tc dng ca mmen do trng tm cm nng h bn ct khng trng

vi ng tm ca trc piston. iu ny c th dn n s mi mn nhanh

ng dn hng v lm hng m kn.






Cm nng h bn ct sm, trt ln-xung dc theo rnh mang c

thng ng. Do cn piston chu lc momen do trng tm cm nng h

60


bn ct sm ko trng ng tm cn piston nn lc ma st trong trng hp

ny tng i nh, tin cho qu trnh tnh ton c th b qua


theo mi quan h:

Cm bn ct sm c trng lng P = 15,67 * 9.81 =153,72 N

3 25153,72

0,274.105,6 10

PA m

p

34 4 0,274.10

0,0193,14

c

AD m

ng knh xi lanh cn thit :

19cD mm

Hnh trnh cn thit ca xi lanh: trong qu trnh my hot ng, bn

ct sm di chuyn ln xung 1 on 40mm.

61


62




63






V piston lin kt cng vi cm bn ct sm nn piston s chu ti bi

tc dng ca mmen do trng tm cm bn ct sm khng trng vi ng

tm ca trc piston. Do ta cn kim tra li bn ca cn piston.


cm m kp. V tr t lc v trng tm ca cm m kp:

G : trng tm ca cm m kp

A : v tr t piston

G

A

40.8

11

Hnh chiu bng ca cm m kp sm trn ( phn i ng)

64


A

G14

6.4

83

40.811

PF

Hnh chiu cnh ca cm m kp sm trn ( phn i ng)

Khong cch on AG:

2 2146,483 40,811 152,06AGL mm

Gc hp bi on AG v mt phng nm ngang

146,483tan 3,59

40,811

74,4o


.cos . 153,72.cos74,4.152,06 6285,91AGM P L Nmm


65


M

A BC

A B C

RA B

6258,91Nmm


3

0,1[ ]

tdMd

Vi tdM = M

3 36258,91

8,550,1[ ] 0,1[100]

tdMd mm

trnh xi lanh b un dc trong qu trnh lm vic, ta kim tra theo

cng thc Euler:

2

2

. .E JK

L

Trong :

Mmen qun tnh J (cm4)

4

64

dJ

M un n hi E (kg/cm2), vi thp chn E=2,1.104kN/cm2

Chiu di tng ng L = m.l theo ph lc 2 m= 1/2)

Lc ti hn K = F.s

H s an ton s (s= 3,5)

22 4

2

22

.1,2.2,1.10 .

. . 64 669,7. 1

.5 .3,52

K E JF kN

s L s


66


5.4.1.3. Xi lanh nng h cm m kp sm trn:

Fms

P

Trong qu trnh lm vic ca my, m kp sm trn c tc

dng gi sm ng v tr ct v dn.

Tnh lc kp cn thit:

Ta c: . .

d

L E AF

L

Trong : L l chiu di on cao su b p trong qu trnh dn

dF l lc cn thit p 2 u sm li vi nhau

L l chiu di vng nh hng nhit

A l din tch mt ct ngang ca sm

E l m un n hi ca cao su

67


Trong qu trnh ct sm, mi bn m kp cch dao 1 on khong

1mm theo phng ngang cha cho cng on dn. Trong qu trnh dn,

2 m kp p st vo nhau, nn di on sm c cha ra l L = 1mm

Khi dao ct i xung ct sm v ngng li 3 giy gia nhit cho 2

u sm, vng nh hng nhit rt kh tnh ton theo cng thc, nhng theo

thc nhim trong qu trnh sn sut (iu chnh lng nhit t c kt

qu dn sm tt nht) th vng nh hng nhit mi u sm l L=2mm

Khi u sm c gia nhit ln n 165oC ( nhit dn) th cao su

trong vng nh hng nhit s chy mm ra, khi m un n hi ca cao

su 165oC ch cn khong 5-10% so vi cao su nhit bnh thng.

Cao su nhit bnh thng c E =6.106N/m2 ( theo bng 3.1 trang 46

gio trnh sc bn vt liu)

M un n hi ca cao su 165oC: E=6.105N/m2

3 5 3 3

3

. . 1.10 .8.10 .(6.10 .68.10 )163,2

2.10d

L E AF N

L

H s ma st gia cao su v thp l 0.7

Lc kp cn thit ca m kp:

163,2

233,10,7

dk

FF N

p sut cn thit trong xi lanh kp

2

3 3

233,197941,2 /

68.10 .35.10

0,98

kFp N mA

p bar

S dng van gii hn p sut lm vic ca 2 xi lanh ny l 3bar(

tng ng 1,5 bar mi xi lanh)

68



V piston lin kt cng vi cm m kp sm trn, nn piston s chu

ti bi tc dng ca mmen do trng tm cm m kp sm trn khng trng

vi ng tm ca trc piston. iu ny c th dn n s mi mn nhanh

ng dn hng v lm hng m kn.






Cm m kp sm trn, trt ln-xung dc theo rnh mang c thng

ng. Do cn piston chu lc momen do trng tm cm m kp ko trng

ng tm cn piston nn lc ma st trong trng hp ny tng i nh,

tin cho qu trnh tnh ton c th b qua


theo mi quan h:

Cm m kp sm trn c trng lng P = 14,94 * 9.81 =146,56 N

3 25146,56

0,977.101,5 10

PA m

p

34 4 0,977.10

0,03523,14

c

AD m

ng knh xi lanh cn thit: D=35,2mm

Hnh trnh cn thit ca xi lanh: trong qu trnh my hot ng, m

kp sm trn di chuyn ln xung 1 on 55mm.

69


70








V piston lin kt cng vi cm m kp sm trn, nn piston s chu

ti bi tc dng ca mmen do trng tm cm m kp sm trn khng trng

71


vi ng tm ca trc piston. Do ta cn kim tra li bn ca cn

piston.


cm m kp. V tr t lc v trng tm ca cm m kp:

G : trng tm ca cm m kp

A : v tr t piston

G

A

50

93.501

78.3

85

80

Hnh chiu bng ca cm m kp sm trn ( phn i ng)

A

G

39.7

93

12.5

Hnh chiu cnh ca cm m kp sm trn ( phn i ng)

Khong cch on AG:

72


2 2 2(78,385 50) (93,501 80) (39,793 12,5) 61,01AGL mm

Gc hp bi on AG v mt phng nm ngang

2 2

39,793 12,5tan 1,66

(78,385 50) (93,501 80)

59o

5959

P

G

F


.cos . 146,56.cos59.60,01 4529,8AGM P L Nmm


73


M

A BC

A B C

RA RB

20 76

4529,8Nmm


3

0,1[ ]

tdMd

Vi tdM = M

3 34529,8

7,680,1[ ] 0,1[100]

tdMd mm


74


5.4.1.4. Xi lanh y cm ngm kp sm trn & di v xi lanh

dn sm:

Trong qu trnh lm vic ca my, cm ngm kp sm trn &

di c tc dng gi sm ng v tr ct v thc hin qu trnh dn

dn. S dng van gii hn p sut lm vic ca xi lanh dn l 5 bar, cn

xi lanh p m kp c p sut 5,6 bar (p sut h thng)


F

Fmsn

F

Fmsn

Cm ngm kp sm trn & di c xi lanh piston y

trt trn rnh mang c. Nh c ch to vi chnh xc cao v

c bi trn thng xuyn trong lc lm vic nn h s ma st trt

gia 2 b mt ca rnh mang c nh (khong 0,12). Ban u 2 cm

ngm kp ng yn nn lc cn thit ca mi xi lanh l:

msn dF F F

Vi msnF l h s ma st ngh - khong 0,16 ( tra theo bng h

s ma st ngh ca mt s loi vt liu Ph lc 1)

75


Vi dF l lc cn thit p 2 u sm li vi nhau, tnh

trn

163,2dF N

. 0,16.52,65.9,81 163,2 245,84dF P F N


theo mi quan h:

3 2

5

245,840,491.10

5 10

FA m

p

34 4 0,491.10

0,0253,14

c

AD m

ng knh xi lanh cn thit :

25cD mm

Hnh trnh cn thit ca xi lanh:

i vi xi lanh 2 xi lanh p 2 m kp sm trn di vo

bn ct sm thc hin qu trnh ct - trong qu trnh ny

mi piston ch di chuyn 1 on khong 5mm

i vi xi lanh thc hin cng don dn sm s y cm

m kp sm trn di bn phi( nh trn hnh v) p st vo

cm bn tri ( cm ny ng yn trong qu trnh dn) -

trong qu trnh ny piston di chuyn 1 on khong 55mm

Do xi lanh p v xi lanh dn sm tc ng vo cng 1 v tr

trn cm kp sm, nn ta chn loi xi lanh kp ( multi position)

76


(http://www.jelpc.com/sct-series-muti-position-cylinder.html)


nh sn sut, ta chn xi lanh :

Cm bn phi (xi lanh kp v xi lanh dn) : ta chn loi

77


SCT32x75-25 c thng s:


Hnh trnh 1 : 75mm

Hnh trnh 2 : 25mm



Kim tra bn cn xi lanh:

trnh xi lanh b un dc trong qu trnh lm vic, ta kim

tra theo cng thc Euler:

2

2

. .E JK

L

Trong :

Mmen qun tnh J (cm4)

4

64

dJ

M un n hi E (kg/cm2), vi thp chn

E=2,1.104kN/cm2

Chiu di tng ng L = m.l theo ph lc 2 m= 1/2)

( l l chiu di lm vic thc, m l h s ph thuc lin kt)

Lc ti hn K = F.s

H s an ton s (s= 3,5)

22 4

2

22

.1,2.2,1.10 .

. . 64 428,63. 1

.7,5 .3,52

K E JF kN

s L s


78


5.4.2.La chn van kh nn:

Van kh nn c chn theo catalog ca hng JELPC

http://www.jelpc.com/4v300-series-valve.html

http://www.jelpc.com/2-2-way-direct-operated-valve.html

Theo catalog ca nh sn sut, van5/2 ta chn loi c m s 4V310-10

c:

Ap sut lm vic t 0,15-0.8Mpa

Tc ng bng l x v nam chm in

79


Theo catalog ca nh sn sut, van 2/2 ta chn loi c m s 2V025-8

c:

Ap sut lm vic t 0,15-0.7Mpa

Tc ng bng l x v nam chm in

80


5.4.3.La chn van gim p:

http://www.jelpc.com/ar,-br-series-regulator.html

Chn loi AR2000

Ap sut iu chnh trong khong: 0,05-0,85 Mpa ~ 0,5-

8,5Bar

Ap sut ti a c th iu chnh: 0,95 Mpa ~ 9,5Bar

Ap sut chu c ti a :1,5 Mpa ~ 15Bar

81


5.4.4.La chn my nn kh:

Tnh ton lu lng kh cn thit:

Din tch piston:

2 2 2

1 2

( );

4 4

D D dA A

Th tch kh cn cho mi piston trong 1 hnh trnh (ra- vo) l:

1 2( ).V A A S

A l din tch piston

S l hnh trnh lm vic ca piston

ng knh v hnh trnh chuyn ng thc ca cc piston:

Xi lanh nng h cm dao ct:




Xi lanh nng h bn ct sm:




Xi lanh nng h cm m kp sm trn:


82




Xi lanh y cm ngm kp sm trn di v xi lanh dn

sm:


Hnh trnh 1 : 55mm

Hnh trnh 2 : 5mm


T cng thc tnh th tch trn, ta tnh c th tch kh cn

thit ca tt c cc piston (1 hnh trnh vo ra ) cho 1 ln ct dn

sm:

3523,19 0,523V cm lit

Thi gian ct dn xong 1 sm xe l 15 giy

Lu lng cn thit khong 2,092 lt/pht

83


Chn my nn kh piston 1 cp ca hng HERTZ

http://www.hertz-kompressoren.com/Products/Reciprocating-

Compressors/Single-Stage-Compressors#bas

Chn loi HPC S1 c:

p sut 8bar

Lu lng 205lt/pht

Dung tch bnh cha 80 lt

84


Chng 6:

THIT K K THUT MAY LU HA

6.1 Yu cu k thut v thng s u vo my lu ha:

Tt c my mc khi thit k ch to u c yu cu k thut qu trnh hot

ng t hiu qu cao. Di y l yu cu k thut ca my lu ha tha

mn iu kin sn xut nh my:

Tnh ton thng s k thut:

Ta c: thi gian lm vic nh my l 7 gi/ ngy

V do nng sut cn t c l 42000 chic/ thng, nn nng sut trung bnh

cn t c l: 200

chic/ gi

Theo cc thit k tham kho ta chn thit k cc my lu ha 2 tng c chu

trnh lu ha cn thit trong khong 5-6 pht l tha yu cu nng sut v:

S sm lu ha trong 1 gi i vi 1 my lu ha 2 tng loi 5-6 pht l: 24

chic/ gi

Nh vy ta c s my cn thit l 9 my l tha yu cu nng sut v ph hp

vi tnh hnh ti chnh nh my

85


6.2 Thit k mch thy lc:

y ta s dng h thng thy lc k hiu A.N.S.I

T phng n thit k ta chn a ra s mch thy lc nh sau:(hnh 6.1)

Hnh 6.1 - S mch thy lc

6.2.1 Nguyn l hot ng:

Chia ra thnh 2 giai on:

+ Giai on 1: u piston i ln p cc khun li vi nhau. giai on ny

di tc dng ca p sut thy lc do bm cung cp ln pha trn a piston,

thanh truyn c gn u p s dch chuyn ra ngoi c th y l thanh

truyn dch chuyn ln pha trn. Khong cch dch chuyn ca thanh

truyn ph thuc vo ngun p lc ca dng thy lc do bm cung cp,

chiu di ca thanh truyn v tc ng ng m ca c cu iu khin

chnh.

86


Van iu khin Solenoid giai on ny, trc chnh di tc dng ca

t trng s dch chuyn sang tri, lc ny cng P ni thng vi cng B

a cht lng vo cylinder, ng thi cng A s thng vi cng T a cht

lng v thng cha thng qua b lc tinh.

+ Giai on 2: y l giai on u p c a tr v v tr ban u. Tng

t nh giai on 1 di tc dng ca p sut do bm cung cp ln pha

mt di ca a piston th lm thanh truyn chuyn ng xung pha di

mang theo u p.

Van Solenoid giai on ny, trc chnh di tc ng ca t trng s

dch chuyn sang pha phi, lc ny cng P s c ni thng vi cng A

a cht lng vo trong cylinder, ng thi cng T s c ni thng vi

cng B a cht lng v thng cha qua b lc.

6.2.2 Tnh ton cc thng s k thut ca tng chi tit.

6.2.2.1 B phn tc ng: Cylinder Piston.

Trong phn ny, chng ta s i tm hiu v b phn tc ng chuyn

ng tnh tin, l: cylinder piston, ng c tnh tin, ng c tuyn

tnh

6.2.2.1.1 Nhim v ca cylinder piston:

Bin i nng lng p sut ca cht lng thnh c nng. C 3 dng b

phn tc ng:

B phn tc ng chuyn ng tnh tin cylinder thy lc.

B phn tc ng chuyn ng quay - ng c thy lc.

B phn tc ng bn quay (gii hn gc quay).

87


6.2.2.1.2 Cc thnh phn c bn ca cylinder-piston: ( hnh 6.2)

Cylinder c hnh tr trn, l b phn c nh, bn trong cylinder c b

phn chuyn ng ti lui theo chu k gi l piston. Piston thng c ni

vi thanh truyn. Trong h thng thy lc, thanh truyn c ni vi piston

truyn ng nng t piston ln ti, cng c trng hp khng dng thanh

truyn piston tc ng trc tip ln ti, lc ny piston thng c gi tn l

Hnh6.2 Cc thnh phn c bn ca cylinder - piston.

thanh y hay tr y. Pha cylinder c thanh truyn nh ra gi l u

thanh v pha khng c thanh truyn gi l u np.

* Cu trc thanh truyn piston:

Hot ng vi c 2 phn trong v ngoi bung cylinder. Phn mt ngoi ca

thanh truyn cn phi phng, cng v vng ai phi kn. Tnh chng mn cn

phi c ch n. Ngi ta thng ph 1 lp crm ln cc b mt ca

88


thanh truyn, tuy nhin lp crm ny c th b r dng t ong, n s to iu

kin cho vic hp th hi nc vo ni y v cui cng dn n nguyn nhn

oxy ha. Trong mi trng nc khc nghit, ngi ta thng s dng thp

c ph 2 lp crm v niken. Thng thng dy ca lp ph t

40150m, thnh thong cng s dng thp chng g thay th. khc

phc nhng khim khuyt ca vt liu kim loi ngi ta ph ln n 1 lp

ceramic.

6.2.2.1.3 Phn loi cylinder-piston:

Cylinder-Piston tc ng n: hnh 6.3

Loi ny c ca np va l ca x chung trong cylinder v piston ch sinh

theo mt chiu chuyn ng. Khi du thy lc c bm vo cylinder, piston

(hay tr y) s chuyn ng v sinh cng. Piston s tr v v tr ban u do

trng lng ca ti hay do lc y ca l xo v du b p tr v bnh cha.

Hnh 6.3 Cylinder - Piston tc ng n

89


Cylinder-Piston tc ng kp:

Trong cylinder-piston tc ng kp,

piston s sinh cng theo c 2 chiu

tnh tin. Du thy lc s vo / ra

trong cylinder c 2 bn piston v

vy trn c 2 u cylinder u c ca

np v ca x. (hnh 6.4)

S lu ng ca ca du thy lc

c iu khin bi van 1 chiu

hoc

bm thy lc o chiu.

Hnh 6.4 Cylinder - Piston tc ng

kp

Cylinder-Piston kiu bc: hnh 6.5

Chiu di ca cylinder-piston l tng chiu di ca thanh n, b dy ca

piston, y, nh v chiu di ca thanh truyn. Kiu cylinder-piston ny

c s dng trong trng hp hn ch v chiu di ca my. Hu ht

cylinder-piston kiu bc u tc ng n.

90


Hnh 6.5 Cylinder - Piston kiu bc Hnh 6.6 Cylinder

Piston kiu pluger

Cylinder-Piston kiu pluger: hnh 6.6

Loi cylinder-piston ny khng c piston hoc piston khng kn vi

cylinder. Cylinder ch dng nh cylinder y, iu ny s dn n piston c

mi quan h v b dy vi thanh truyn.

6.2.2.1.4 Tnh chn cylinder-piston:

Cc piston ca cylinder cng tc c lm c hoc rng. Piston truyn

lc ti u p v chu nn. Kiu lin kt gia piston vi u p c th l kiu

lin kt cng (ui piston ngm cht u vo u p).

Cc cylinder thng c ch to theo kiu rn t thp Cacbon 45 hoc

60, b mt ca chng c ti v nh bng cn thn ( nhm b mt khng

qu 0.63 v chnh xc tng ng cp 2 khi lp vo ng dn hng). Cc

piston c lin kt cng vi u p, thng c ch to t thp hp kim

crm mlipden, cng b mt cng tc ca piston bng 4860HRC.

91


* Tnh ton cc thng s k thut ca cm cylinder piston:

Gi Dc - l ng knh trong ca cylinder, mm.

Dr - l ng knh ca trc piston, mm.

A - l din tch mt trong cylinder, din tch a piston, mm2.

p - l p sut ca h thng thy lc, N/m2.

F - l ti trng lm vic, N.

Theo nh yu cu thit k lp xe quy cch 2.25/2.5-17, 2.75/3-17,

2.25/2.5- 16, 2.75/3-14, 3.5/4-10 nng sut 30.000 chic/ thng

Ta v c cc khun, ph hp vi cc kch thc lp quy cch trn sau

dng phn mm solidworks tnh ton khi lng.

92


Hnh 6.7 M hnh thit k 3D my lu ha 2 tng

Theo nh m hnh cho thy th c cu cylinder- piston chu trng lng ca: b

khun di, khun di, khun gia, 3 lng khun cha sm xe, vt liu

ch to tt c u lm bng thp c.

Dng phn mm solidworks sau khi thit k ta c trng lng cn thit nh

sau:

*B khun di: 64492.92 grams

Hnh 6.8 trng lng b khun di

93


*Khun di: 61788.18 grams

Hnh 6.9 trng lng khun di

*Khun gia: 67447.94 grams

94


Hnh 6.10 trng lng khun gia

*3 Lng khun cha sm xe: n c tnh cho khun cha sm quy cch 2.25-17

Ta c khi lng l :

Hnh 6.11 trng lng lng khun cha sm

95


Nh vy: F =(65+62+70+104) x 9.81 = 2953 (N).

y ta chn p sut ca h thng p=85 (bar). Cylinder lm t thp c c

[] = 80100 MPa.

Kim tra li theo cng thc (3.4.2f), ta c p sut ti u ca h thng:

32

OTp =

32

10.100 6

28900000 (N/m2) = 289 (bar).

Nh vy pOT > p. Nn ta chp nhn p sut ca h thng p = 85 bar.

T p sut h thng ta suy ra cc thng s ca cylinder piston theo mi

quan h k thut:

245 10310852593

mp

FA

mA

Dc 02.014.3

10344 4

Nh vy theo bng 4.1(trg140-Ti liu I), ta chn Dc=56(mm).

V ng knh thanh truyn Dr=50(mm).

* Chiu di thanh truyn piston L, mm.

m bo sc bn ca thanh truyn piston khi lm vic, chiu di Lp ca

trc piston phi tha mn cng thc sc bn vt liu sau:

2

2

L

EJK

Vi K ti trng ti hn, kg;

E mun n hi, E=2.1x106 kg/cm2 (i vi thp);

. J mmen qun tnh i vi tm thanh truyn.

96


64

4dJ

(cm4)

Nh vy ta thay cc s liu vo, ta c L:

64195

2101.214.3 4632

K

EJL

288.71 (mm).

m bo bn trc piston ta chn Lp= 695(mm).

6.2.2.2 H thng van:

6.2.2.2.1 Nhim v ca van thy lc :

Van thy lc c nhim v iu khin dng thy lc, tn hiu iu khin v

b phn tc ng thy lc. Van thy lc thng c s dng iu khin tc

dng, iu khin hng v iu khin p sut thy lc. Tuy nhin mt s

van c a chc nng, c th thc hin nhiu nhim v iu khin.

Tn hiu iu khin van c th l tn hiu c kh, tn hiu bng tay, thy

lc, kh nn hoc in. Tc ng ca van iu khin c th l tn hiu s

(digital) hay tn hiu tng t (analogue).

Thng thng van c nhng chc nng sau:

Van trn c s dng gi p sut ca mch thy lc.

Van trc ng 4 cng c th s dng thay i trc tip chiu quay ca m

t thy lc.

Van iu khin lu lng s dng thay i tc ca b tc ng.

Trong thc t th 2, 3 hoc nhiu van c ni vi nhau thnh 1 van ghp c

nhiu chc nng.

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6.2.2.2.2 Phn loi van thy lc :

Cc van c nh gi bng kch thc, kh nng chu p lc v mc

gim p. C rt nhiu kiu thit k van thy nhng nhn chung li th c mt

s van chnh sau y.

Van trn p: loi ny s dng trn mt s ni trong my thy lc, trn

ng v ca mch duy tr p sut trong thng thy lc, trn ng ng

dn. Trn cylinder thy lc khi qu ti, ng ng thy lc khng b

nt v. Trong cc thng cha duy tr mt p sut ngn khng cho nc

ng li v nhim.

Van gim p: loi van ny s dng gii hn p sut khng vt qu mc

yu cu ca mch. y l loi van thng m, p sut vo s cn bng vi

lc l xo, khi p sut tng ln th thng lc l x v dng lu cht s chy qua

van v thng cha nn p sut gim.

Van tun t: van ny c s dng truyn dng thy lc n h thng

th cp, ch sau khi c hot ng xy ra trong h thng s cp. y l loi

van thng ng, v ch m dng thy lc ra n h thng th cp, khi h

thng s cp t n ngng p sut thit t trc. p sut ca h thng s

cp s c duy tr li sau khi van thc hin hot ng th t.

Van 1 chiu: loi van n gin nht, y l loi van hot ng ch c 1 chiu

i khng c chiu ngc li, n cho php tch tr np hoc duy tr p lc

khi my khng hot ng.

Van 1 chiu c ng iu khin: y l van 1 chiu thng ng nhng c

th iu khin bng tn hiu t bn ngoi. V d nh ti trng khng th gi

c bi p sut ca van 1 chiu. Thng thng, p sut bn ngoi vo

ng ng khc c kt ni vi m t hay cylinder.

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Van treo ti: thc cht van treo ti l 1 dng c bit ca van 1 chiu c

ng iu khin. Nhng ngc li vi van 1 chiu l c th m hoc ng,

van treo ti ch 1 phn nh ca van iu khin lu lng c ng iu

khin.

Van ngt: loi van ny c thit k nh mt thit b t ng bt kn cc

ng dn thy lc nu nh p sut thy lc qu cao hoc qu thp hn p

sut nh.

Cc loi van ph tr: cc h thng thy lc phc tp thng hay s dng

nhng khi van ph tr thc hin nhng chc nng phc tp khng th

thy c nh b tch tr thy lc, qut lm mt. Cc van ny thng c

thit k ph hp cho nhng my ring bit.

6.2.2.2.3 Chn van thy lc :

Theo s mch thy lc phn trn, ta chn 3 loi van:

Van trn p.

Van 1 chiu.

Van Solenoid.

Sau y l phn tnh ton 3 loi van c nu trn.

6.2.2.2.3.a. Van 1 chiu: (hnh 6.12a)

Van 1 chiu bao gm 1 thn van c cng vo v cng ra, 1 l xo, v 1 vin bi.

99


Hnh 6.12a S kt cu van mt chiu.

6.2.2.2.3.b. Van trn: (hnh 6.12b)

Van trn c 1 l xo, 1 vt iu chnh, 2 cng P v T. Cng T l ni cht

lng s v thng du khi van m. y l van thng ng, van m khi p lc

cht lng trn ng ng thng c lc l xo, y thanh chn qua tri lm

cht lng s thng vi cng T m v thng cha, p lc trong mch s gim

n khi no cn bng vi lc l xo.

Hnh 6.12b S kt cu van trn.

6.2.2.2.3.c Van solenoid: (hnh 6.12c)

Van solenoid c 4 cng. Cng P ni vi thng cha, cng T a cht

lng v, cng A v B l 2 cng ni vi ng ng chnh.

Van solenoid hot ng da trn hin tng cm ng t. Khi cun dy c in

s bin li st thnh nam chm v ng thi ht ng cun v pha li st lm

cho ng cun chuyn ng. Qu trnh ny s lm ng m cc cng van v van

solenoid hot ng. Khi mt in th di tc dng ca lc l xo th ng cun

s tr v v tr cn bng ban u.

100


Hnh 6.12c S kt cu van Solenoid.

6.2.2.3 Bm thy lc:

6.2.2.3.1 Nhim v ca bm thy lc:

y du thy lc vo h thng v to nn dng lu ng. C th ni

bm chuyn c nng thnh nng lng p sut trong lu cht, sau nng

lng p sut li chuyn thnh c nng trn b phn tc ng.

Cc thnh phn c bn ca bm thy lc gm: (hnh 6.13)

101


Hnh 6.13 Cc thnh phn c bn ca mt my bm

Mt ca np a du t bnh cha hoc t ngun cha vo bm.

Mt ca thot du ni vi ng ng p lc.

Bung bm ti du t ca np n ca thot.

Cc c cu khc m bo hot ng ca bm.

Cc dng bm thy lc s dng ph bin

+ Bm bnh rng: n gin, r tin, bn, hiu sut cao, thch hp cho h

thng c p sut di 300 bar (3x107N/mm2).

+ Bm cnh qut: n gin, r tin, tin cy cao. Loi ny dng tt vi h

thng c lu lng

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