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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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2 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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3 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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4 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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5 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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6 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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7 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
- 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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8 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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9 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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10 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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11 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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12 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
Hnh .2.1: my ni
Hnh .2.2: cng on ni thnh rut xe trn kn
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13 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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14 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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15 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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16 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
+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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17 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
-- 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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18 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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19 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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20 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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21 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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22 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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23 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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24 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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25 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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26 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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27 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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28 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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29 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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30 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
3.4.3. Thit b
Hnh v
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31 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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32 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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33 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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34 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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35 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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36 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
4.1.2.3. Phng n 3: Truyn ng bng kh nn:
a. S nguyn l
Rnh truot mang cPiston
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37 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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38 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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39 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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40 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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41 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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42 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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43
43 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
.
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.
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44 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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45 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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:
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46 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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 .
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47 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
48 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
49 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
50 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
51 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
52 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
53 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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54
54 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
Hnh trnh cn thit ca xi lanh: trong qu trnh my hot ng, dao
ct di chuyn ln xung 1 on 145mm.
-
55
55 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
56 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
57 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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:
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58
58 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
59 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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 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
60 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
T p sut lm vic ta suy ra cc thng s s b ca xi lanh piston
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.
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61
61 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
-
62
62 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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 SC32x50 c:
-
63
63 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
ng knh piston : 32mm
Hnh trnh piston : 50mm
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 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.
S dng phn mm Autodesk Inventor 2011 tm trng tm ca
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
64 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
Momen un tc dng ln u cn piston :
.cos . 153,72.cos74,4.152,06 6285,91AGM P L Nmm
Phn tch lc tc dng ln trc piston v biu momen un:
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65
65 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
M
A BC
A B C
RA B
6258,91Nmm
Kim tra li ng knh trc theo cng thc:
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
Vy piston chn tho mn yu cu
-
66
66 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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67
67 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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)
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68
68 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
Xi lanh lm t thp c c [] = 80100 MPa.
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.
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 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
T p sut lm vic ta suy ra cc thng s s b ca xi lanh piston
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.
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69
69 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
-
70
70 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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 SC40x75 c:
ng knh piston : 40mm
Hnh trnh piston : 75mm
ng knh cn piston : 16mm
p sut lm vic t 1-9kgf/cm2 (0,981 8,829 bar)
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
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71
71 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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 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
72 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
Momen un tc dng ln u cn piston :
.cos . 146,56.cos59.60,01 4529,8AGM P L Nmm
Phn tch lc tc dng ln trc piston v biu momen un:
-
73
73 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
M
A BC
A B C
RA RB
20 76
4529,8Nmm
Kim tra li ng knh trc theo cng thc:
3
0,1[ ]
tdMd
Vi tdM = M
3 34529,8
7,680,1[ ] 0,1[100]
tdMd mm
Vy piston chn tho mn yu cu
-
74
74 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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)
Xi lanh lm t thp c c [] = 80100 MPa.
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)
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75
75 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
T p sut lm vic ta suy ra cc thng s s b ca xi lanh piston
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)
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76
76 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
(http://www.jelpc.com/sct-series-muti-position-cylinder.html)
Theo kt qu tnh ton s b kch thc xi lanh v theo catalog ca
nh sn sut, ta chn xi lanh :
Cm bn phi (xi lanh kp v xi lanh dn) : ta chn loi
-
77
77 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
SCT32x75-25 c thng s:
ng knh piston : 32mm
Hnh trnh 1 : 75mm
Hnh trnh 2 : 25mm
ng knh cn piston : 12mm
p sut lm vic t 1-9kgf/cm2 (0,981 8,829 bar)
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
Vy piston chn tho mn yu cu
-
78
78 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
79 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
80 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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81
81 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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:
ng knh piston : 32mm
Hnh trnh piston : 150mm
ng knh cn piston : 12mm
Xi lanh nng h bn ct sm:
ng knh piston : 32mm
Hnh trnh piston : 50mm
ng knh cn piston : 12mm
Xi lanh nng h cm m kp sm trn:
ng knh piston : 40mm
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82 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
Hnh trnh piston : 55mm
ng knh cn piston : 16mm
Xi lanh y cm ngm kp sm trn di v xi lanh dn
sm:
ng knh piston : 32mm
Hnh trnh 1 : 55mm
Hnh trnh 2 : 5mm
ng knh cn piston : 12mm
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
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83
83 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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84 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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85 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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86 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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).
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87 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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88 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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89 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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90 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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91 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
* 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.
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92 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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93 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
*Khun di: 61788.18 grams
Hnh 6.9 trng lng khun di
*Khun gia: 67447.94 grams
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94 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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
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95 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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96 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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97 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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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98 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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99 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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.
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100 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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)
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101 Trng i Hc Bch Khoa TP.HCM Lun vn tt nghip Khoa C Kh
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