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Lp: C in t - K53 GVHD: TS.NGUYN HU CH
1
B GIO DC V O TO CNG HA X HI CH NGHAVITNAM
TRNG I HC GTVT CS2 c Lp T Do Hnh Phc
THIT K MN HC
TRUYN NG CNG SUT NHM 3
Tn v tm tt yu cu, ni dung bi tp ln: chc nng nguyn l lm vic ca cc phn t iu khin trong cc hp s t ng Ni dung ca bng thuyt minh, cc yu cu chnh:
1. Tng quan hp s t ng 2. Cu to v cc cm chi tit chnh trong h thng iu khin ca hp s 3. Nguyn l hot ng ca h thng iu khin ca hp s 4. Kt lun v nh gi
Phn 1: Nguyn Thanh Huy Phn 2,3,4: L Vn Kh, ng Ngc Khnh, L Danh Lam
GVHD: TS. NGUYN HU CH SVTH: NGUYN THANH HUY
L VN KH NG NGC KHNH
L DANH LAM
Nhm: 3
Lp: C in t-K53
Lp: C in t - K53 GVHD: TS.NGUYN HU CH
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MC LC
I. Tng quan v hp s t ng .............................................................................. 4
1.1. Gii Thiu Chung: .............................................................................................. 4
1.1.1..Khi qut: ....................................................................................................... 4
1.1.2. Lch s pht trin. .......................................................................................... 5
1.1.3. Phn loi ......................................................................................................... 7
1. Phn loi theo t s truyn :................................................................................ 7
2. Phn loi theo cch iu khin:.......................................................................... 9
3. Phn loi theo cp s truyn ............................................................................12
4. Phn loi theo cch b tr trn xe. ....................................................................12
1.1.4. Chc nng ca hp s t ng: ....................................................................14
1.1.5 iu kin lm vic ca hp s t ng .........................................................14
1.1.6 u, nhc im ca hp s t ng .............................................................14
II.Cu to v nguyn l lm vic ca cc phn t iu khin HSHT ...............16
2.1 Cc loi Phanh di..............................................................................................17
2.2 Cc loi ly hp kha lm vic trong du ...........................................................22
2.3 Cc khp mt chiu ...........................................................................................25
2.4 C cu kha trc b ng ...................................................................................28
2.5 H thng van ......................................................................................................31
2.5.1 Van iu p s cp: .....................................................................................32
2.5.2 Van iu Khin ..........................................................................................33
2.5.3 Van Chuyn S ...........................................................................................34
2.5.4 Van in T ................................................................................................35
2.5.5Van Bm Ga ..............................................................................................36
2.5.6 Van iu p th cp ....................................................................................37
2.5.7 Cc Van Khc .............................................................................................39
2.6 Cm bin ............................................................................................................40
2.6.1 Cm bin v tr bm ga : ...........................................................................40
2.6.2 Cm bin nhit nc lm mt: ...............................................................43
2.6.3 Cm bin tc : .........................................................................................44
III. Kt lun v nh gi .......................................................................................46
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Nhn xt ca GVHD:
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I. Tng quan v hp s t ng
1.1. Gii Thiu Chung:
1.1.1..Khi qut:
Trn xe s dng hp s thng, th li xe phi thng xuyn nhn bit ti v tc ng c chuyn s mt cch ph hp.
Khi s dng hp s t ng, nhng s nhn bit nh vy ca li xe l khng cn thit. Vic chuyn n v tr s thch hp nht c thc hin mt cch t ng theo ti ng c v tc xe.
Vi cc xe c hp s t ng th ngi li xe khng cn phi suy tnh khi no cn ln s hoc xung s. Cc bnh rng t ng chuyn s tu thuc vo tc xe v mc p bn p ga.
Mt hp s m trong vic chuyn s bnh rng c iu khin bng mt ECU (B iu khin in t) c gi l ECT-Hp s iu khin in t, v mt hp s khng s dng ECU c gi l hp s t ng thun thu lc. Hin nay hu ht cc xe u s dng ECT. i vi mt s kiu xe th phng thc chuyn s c th c chn tu theo mun ca li xe v iu kin ng x. Cch ny gip cho vic tit kim nhin liu, tnh nng v vn hnh xe c tt hn.
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Hnh 1.1: S dng hp s t ng
1.1.2. Lch s pht trin. Ngay t nhng nm 1900, tng v mt loi hp s t ng chuyn s c cc k s hng hi c nghin cu ch to. n nm 1938, hp s t ng u tin ra i khi hng GM gii thiu chic Oldsmobile c trang b hp s t ng. Vic iu khin t c n gin ha bi khng cn bn p ly hp. Tuy nhin do ch to phc tp v kh bo dng sa cha nn n t c s dng. n nhng nm 70 Hp s t ng thc s hi sinh khi hng lot hng t cho ra cc loi xe mi vi hp s t ng i km. T n nay hp s t ng pht trin khng ngng v dn thay th cho hp s thng. Khi mi ra i, hp s t ng l loi c cp v c iu khin hon ton bng thy lc. chnh xc ha thi im chuyn s v tng tnh an ton khi s dng, hp s t ng c cp iu khin bng in t (ECT) ra i.
Vn cha hi lng vi cc cp t s truyn ca ECT, cc nh sn xut t nghin cu, ch to thnh cng mt loi hp s t ng vi v s cp t s truyn (hp s t ng v cp) vo nhng nm cui ca th k XXc th nh sau:
Hp s t ng (HSTD), theo cng b ca ti liu cng nghip t CHLB c, ra i vo 1934 ti hng Chysler. Ban u HSTD s dng Ly hp thy lc v Hp s hnh tinh, iu khin hon ton bng van con trt thy lc, sau chuyn sang dng Bin mmen thy lc n ngy nay, tn gi ngy nay dng l AT.
Tip sau l hng ZIL (Lin x c 1949) v cc hng Ty u khc (c, Php, Thy s). Phn ln cc HSTD trong thi k ny dng hp s hnh
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tinh 3, 4 cp trn c s ca b truyn hnh tinh 2 bc t do kiu Willson, kt cu AT.
Sau nhng nm 1960 HSTD dng trn t ti v t but vi Bin mmen thy lc v hp s c kh c cc cp bnh rng n khp ngoi, kt cu AT.
Sau nm 1978 chuyn sang loi HSTD kiu EAT (iu khin chuyn s bng thy lc in t), loi ny ngy nay ang s dng.
Mt loi HSTD khc l hp s v cp s dng b truyn ai kim loi (CVT) vi cc h thng iu khin chuyn s bng thy lc in t, (cng l mt dng HSTD).
Ngy nay bt u ch to cc loi truyn ng thng minh, cho php chuyn s theo thi quen li xe (thay i tc ca ng c bng chn ga) v tnh hung mt ng, HSTD c 8 s truyn . H thng truyn lc s dng HSTD c gi l h thng truyn lc c kh thy lc in t, l khu vc c nhiu ng dng ca k thut cao, s pht trin rt nhanh chng, chng hn, gn y xut hin loi hp s c kh nng lm vic theo hai phng php chuyn s: bng tay, hay t ng ty thuc vo thch ca ngi s dng.
Hin nay p ng nhu cu ca khch hng v tng tnh an ton khi s dng, cc nh ch to cho ra i loi hp s iu khin bng in t c thm chc nng sang s bng cn nh hp s thng.
Hnh1.2:Hp s t ng ngy nay
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Ngy nay hp s t ng c s dng kh rng ri trn cc xe du lch, thm ch trn xe 4WD v xe ti nh. nc ta, hp s t ng xut hin t nhng nm 1990 trn cc xe nhp v t M v chu u. Tuy nhin do kh nng cng ngh cn hn ch, vic bo dng, sa cha rt kh khn nn vn cn t s dng. Hin nay, cng vi nhng tin b ca khoa hc k thut, cng ngh ch to hp s t ng cng c hon chnh, hp s t ng khng nh c tnh u vit ca n v dn thay th cho hp s thng.
1.1.3. Phn loi
C nhiu cch phn loi hp s t ng. 1. Phn loi theo t s truyn :
Hp s t ng v cp: L loi hp s c kh nng thay i t ng, lin tc t s truyn nh s thay i bn knh quay ca cc puly. Hp s v cp trn t ch yu l kiu truyn ng bng thy lc.
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Hnh: 1.3 Hp s t ng v cp
u im: kt cu n gin, hiu sut truyn ng cao, kch thc nh gn. ng c khng b chuyn trng thi t ngt, gip ti u ha qu trnh hot ng v gin tip gim mc n xng. Nhc im: C t s truyn gii hn, c tay s gii hn v khi ra vo s phi thay i ch lm vic ca ng c. Ch to phc tp dn ti gi thnh cao. Phm vi s dng: hin nay c s dng nhiu trn cc loi xe du lch, xe yu cu kch c nh gn. Kt cu gn gng, chc chn, d iu khin bo dng v sa cha, gi thnh h.
Hp s t ng c cp: Khc vi hp s v cp, hp s t ng c cp cho php thay i t s truyn theo cc cp s nh cc b truyn bnh rng. Kiu hp s c cp gm mt s cp hu hn ( thng t 3 n 20 cp), ng vi mi cp gi tr m men v do tc truyn qua hp s l khng i. u im: kt cu n gin, hiu sut truyn ng cao, kch thc nh gn. Nhc im: c t s truyn gii hn, c tay s gii hn v khi ra vo s phi thay i ch lm vic ca ng c. Phm vi s dng: c s dng rng di trn hu ht cc dng xe hin nay.
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Hnh 1.4: Hp s t ng c cp
2. Phn loi theo cch iu khin: Theo cch iu khin c th chia hp s t ng thnh hai loi, chng khc nhau
v h thng s dng iu khin chuyn s v thi im kha bin m. Mt loi l iu khin hon ton bng thy lc, loi kia l iu khin in t (ECT), n s dng ECU iu khin v c thm chc nng chn on v d phng.
Hp s iu khin hon ton bng thy lc hot ng bi s bin i mt cch c kh tc xe thnh p sut ly tm v m bm ga thnh p sut bm ga ri dng cc p sut thy lc ny iu khin hot ng ca cc ly hp v phanh trong trong cm bnh rng hnh tinh, do iu khin thi im ln xung s. N c gi l phng php iu khin thy lc.
Mt khc, i vi hp s iu khin in t ECT, cc cm bin pht hin tc xe v m bm ga bin chng thnh tn hiu in v gi chng v b iu khin ECU. Da trn tn hiu ny ECU iu khin hot ng cc ly hp, phanh thng qua cc van v h thng thy lc.
- Hp s t ng iu khin hon ton bng thy lc: iu khin chuyn s c hc bng cch pht hin tc xe bng thu lc thng qua van iu tc v pht hin m bn p ga t bm ga thng qua dch chuyn ca cp bm ga.
Loi iu khin in t kt hp thy lc Loi ny s dng ECU- ECT iu khin hp s thng qua cc tn hiu iu khin in t.
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S tn hiu iu khin: Tn hiu in ca cc cm bin ( cm bin tc , cm bin v tr chn ga.) v tn hiu thy lc t bn p ga ( qua cp chn ga bm gacm bin v tr bm ga) ECU ng c ECT- ECU Van in t cc can sang s b bnh rng hnh tinh v b bin m
Hnh 1.5: Hp s t ng toytota
Loi iu khin in t hon ton thy lc: Loi ny s dng cp bm ga v cc tn hiu in t iu khin iu khin hp s t ng. S tn hiu iu khin: Bn p ga cp dy ga cp bm ga van bm ga, van ly tm van sang s b truyn bnh rng hnh tinh v b bin m.
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Hnh1.6: Hp s t ng iu khin hon ton thy lc
Hp s t ng iu khin bng in t: Hp s ny s dng p sut
thu lc t ng chuyn s theo cc tn hiu iu khin ca ECU. ECU
iu khin cc van in t theo tnh trng ca ng c v ca xe do cc b
cm bin xc nh, t iu khin p sut du thu lc.
S tn hiu iu khin:
Tn hiu in t cc cm bin (cm bin chn ga, cm bin du hp s, cm bin tc ng c, cm bin tc xe, cm bin m vng quay, cm bin tc tuabin .. vv )v tn hiu in t b iu khin thy lc ECT ngc v ECT tn hiu in n cc van in t b bin m v bnh rng hnh tinh.
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3. Phn loi theo cp s truyn
C nhiu loi hp s t ng, hin nay thng dng nht l loi 4, 5, 6 cp s, c mt s loi xe cn c trang b hp s t ng 8 cp.
4. Phn loi theo cch b tr trn xe.
- Loi FF: Hp s t ng s dng cho xe c ng c t trc, cu trc ch ng. Loi
ny c thit k gn do chng c b tr khoang ng c.
Hnh1.7: S nguyn l hp s t ng iu khin bng in t
Hnh 1.5: Hp s t ng iu khin in t.
Hnh1.8: Hp s t ng 8 cp ca trung quc loi FF
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Hnh 1.9: Hp s t ng loi FF - Loi FR: Hp s t ng s dng cho xe c ng c t trc, cu sau ch
ng. Loi ny c b truyn bnh rng cui cng (vi sai) lp bn ngoi nn n di hn.
Hnh 1.10: Hp s t ng loi FR
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1.1.4. Chc nng ca hp s t ng:
V c bn hp s t ng c chc nng nh hp s thng, tuy nhin hp s t ng cho php n gin ha vic iu khin hp s, qu trnh chuyn s m du, khng cn ngt ng truyn cng sut t ng c xung khi sang s. Hp s t ng t chn t s truyn ph hp vi iu kin chuyn ng ca t, do to iu kin s dng gn nh ti u cng sut ng c.
V vy, hp s t ng c nhng chc nng c bn sau: - To ra cc cp t s truyn ph hp nhm thay i moment xon t ng c n
cc bnh xe ch ng ph hp vi moment cn lun thay i v nhm tn dng ti a cng sut ng c.
- Gip cho xe thay i chiu chuyn ng. - m bo cho xe dng ti ch m khng cn tt my hoc tch ly hp. Ngoi ra ECT cn c kh nng t chn on.
1.1.5 iu kin lm vic ca hp s t ng
Hp s t ng lm vic trong iu kin t s truyn lun thay i v vy trong
qu trnh lm vic cc chi tit nhanh b mi mn.
Hp s t ng nm di gm xe nn d b bi bn v c kh nng b va p
gy hng hc.
1.1.6 u, nhc im ca hp s t ng
a) u im:
- N gim mt mi cho li xe bng cch loi b cc thao tc ct ly hp v
thng xuyn phi chuyn s.
- N chuyn s mt cch t ng v m du ti cc tc thch hp vi ch
li xe do vy gim bt cho li xe s cn thit phi thnh tho cc k thut
li xe kh khn v phc tp nh vn hnh ly hp.
- N trnh cho ng c v dng dn ng c tnh trng qu ti do n ni
chung bng thy lc qua bin m tt hn so vi ni bng c kh.
- Hp s t ng dng ly hp thy lc hoc bin m thy lc vic tch ni
cng sut t ng c n hp s nh s chuyn ng ca dng thy lc t
cnh bm sang tua bin m khng qua mt c cu c kh no nn khng c s
ngt qung dng cng sut v vy t hiu sut cao (98 %).
- Thi gian sang s v hnh trnh tng tc nhanh.
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- Khng b va p khi sang s, khng cn b ng tc.
b) Nhc im
- Kt cu phc tp hn hp s c kh.
- Tn nhiu nhin liu hn hp s c kh.
- Bin m ni ng c vi h thng truyn ng bng cch tc ng dng cht
lng t mt ny sang mt khc trong hp bin m, khi vn hnh c th gy ra hin
tng trt hiu sut s dng nng lng b gim, c bit l tc thp.
Tm li ta c th tm tt mt cch y v cc loi hp s nh sau:
Hp s t ng
Hp s v cp Hp s t ng c cp
Hp S V cp iu khin bng dy ai
Hp S V cp iu khin bng con ln
Hp S C Cp loi thng
Hp S C Cp loi in t
S t ng loi chuyn s bng Cn iu khin Thy lc
S t ng loi thng chuyn s bng Cn v
Phanh.iu khin thy lc
S t ng chuyn s bng cn iu khin Thy lc v in T(ECT,ECU)
S t ng chuyn s bng iu Cn v
Phanh
khin Thy lc v in T(ECT,ECU).
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c im: Loi hp s CVT vn hnh trn
mt h thng pu-li, dy ai thng minh,
h thng ny cho php mt kh nng bin thin v hn gia s thp nht v s cao nht m khng
khng c s ngt qung gia cc s.
c im: Loi hp s CVT vn hnh trn
mt h thng a con ln thng minh,
h thng ny cho
php mt kh nng bin thin v hn gia s thp nht v s cao nht m khng
khng c s ngt qung gia cc s.
c im: S dng bin m v cn vo s mt cch t ng.iu khin chuyn s bng thun thy lc ty
c im: S dng bin m v cn,
phanh chuyn s mt cch t ng.iu khin chuyn s bng Thy lc thun ty
c im: S dng bin m v cn vo s mt cch t ng. Chuyn s bng cn iu khin Thy lc v in T (ECT,
ECU).
c im: S dng bin m v cn, phanh
chuyn s mt cch t ng.iu khin chuyn s bng Thy lc v in T (ECT, ECU).
* Cu to v nguyn l hot ng ca hp s t ng
Hin nay, hp s t ng trn xe c 3 cm b phn chnh 1. B bin m. 2. B truyn ng bnh rng hnh tinh.
3. B iu khin thy lc (i vi hp s iu khin hon ton bng thy lc)
hoc b iu khin in t kt hp thy lc (i vi hp s iu khin bng in
t). Ngoi ra, trn hp s t ng cn c cc c cu v cc h thng iu khin
khc nh: c cu chuyn s c kh, h thng lm mt du hp s, h thng kha
cn s (shift-lock system), h thng kha cng tc my(keyinterlocksystem)
II.Cu to v nguyn l lm vic ca cc phn t iu khin HSHT Cc phn t iu khin trong HSHT Gm:
Cc loi phanh di
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Cc loi ly hp kha lm vic trong du
Cc khp mt chiu
Khp an ton kha trc b ng
H thng van
Cm bin
2.1 Cc loi Phanh di
Trong HSHT phanh di dung kha 1 chi tit no vi v hp s hoc dung kha trc b ng ca hp s khi cn chn s nm v tr P .Cu to phanh di bao gm: b mt tr ca chi tit cn kha c gi l tang trng, hai u ca phanh c cu trc a dng ph thuc vo c cu iu khin. Cu to phanh di c th chia thnh 2 loi: *Loi iu khin trc tip: tc ng iu khin t vo 1 u di phanh thng qua xy lanh iu khin, mt u nm ta trn v. Mt trong 2 u ca phanh cho php iu chnh khi cn thit. *Loi iu khin tc ng kp vo c 2 u, c gi l kt cu servo a. Mt s kt cu phanh di iu khin mt u Di phanh c cu to t tht l mng, b mt trong c dng 1 lp atbet c chiu dy 0,8 n 1,2mm lm b mt ma st . Cu trc hai u ca di phanh to nn cc im t. Tang trng l b mt hnh tr trn .Gia hai b mt lm vic c khe h nh m bo tang trng quay t do .Khe h ny c quyt nh bi c cu c bu lng iu chnh .Khi phanh momen ma st truyn qua cc u t tc dng vo v hp s.
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Hnh 1-11 Cu to ca phanh di trn hp s NISSAN BLUBIRD
a) Cu to chi tit ; b) Mt ct
Cm pittong xy lanh iu khin nm trn vch ngn ca hp s, mt u cn y t vo pittong, cn u kia t vo im t ca phanh di. Trong kt cu ca HSHT ny v trn nhiu hp s khc s dng hai pittong iu khin. Mt pittong ln dung ng phanh, pittong b nm trong pittong ln iu khin m phanh. Trong h thng thy lc dufnh hai thng du ti xy lanh. Nu mt ng du c p sut cao th ng du kia l ng du hi v ngc li. Nh kt cu nh vy vic ng m phanh din ra trong thi gian qu rt ngn m bao cho qu trnh chuyn s dt khot v m du. Loi ny c gi l xy lanh pittong kp. + Phanh di ca hang FORD (H 1-12) Cu to tng t nh hnh 1-11, nhng cu trc ny n t dng n ni nhm tng kh nng t la cho c cu khi lm vic m bo tip xc u trn ton chu vi ca di phanh .u t ta ln v to iu kin iu chnh khe h gia di phanh v tang trng .u vt t nm phn di ca v hp s, khi iu chnh khng cn tho y du.
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Hnh 1-12. Cu to phanh di ca hng FORD Phanh di iu khin mt u mt u vi xy lanh iu khin dng n , trong c cu b tr l xo c cng cao nh phanh nhanh chng .Mt s phanh di c kt cu u ta c nh khng iu chnh c nh trn hnh 1-13 . Vic iu chnh thc hin trn u ta iu khin .Khi tin hnh iu chnh s phi tho y du ca hp s .Cng vic iu chnh s c tin hnh ng thi vi vic tho ra li lc ca h thng thy lc b. Phanh di iu khin hai u Phanh di iu khin hai u bng mt xy lanh tc dng mt chiu nh trn hnh 1-14. Phn iu khin c cc n lm vic dng lin ng
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Hnh 1-13 Cu to phanh di ca hng FIAT C cu iu chnh khe h di phanh, tang trng, theo dng cam t gia hai
on ko, v to nn im ta khi lm vic. Phanh di loi ny c hiu qu to nn momen phanh ln , c dung cho cc s truyn thp m kch thc kt cu bn trong khng ln
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Hnh 1-14 Cu to di hai u iu khin ca hng FORD
Cc loi phanh di u cn phi kim tra, iu chnh nh k. Khe h ca di phanh vi tang trng quyt nh trng thi lm vic ca phanh di, v vy sau qu trnh s dng khe h gia chng ln dn dn ti gim hiu qu phanh. Khi tho lp cn kim tra cht lng b mt ca di phanh v tang trng nhm pht hin cc vt trc r trn sut chiu di ca di phanh, ng thi iu chnh ng ke h cn thit. Phanh di lm vic trong du c bn rt cao. Nhng trong qu trnh s dng thng hay hng, nguyn nhn ch yu l do khng s dng ng ch lm vic ca hp s. Cc nguyn nhn h hng c th l:
- cn chn s v tr thp li tng chn ga qu mc vi thi gian di.
- Du thiu hoc du khng ng chng loi quy nh dn ti hin tng tng
nhit du qu mc hoc b nung nng cc b di phanh, di phanh c th
b bong trc v gy ra hin tng kt s bt thng.
- Phanh di dng cho vic kha trc di ng ca hp s cng c kt cu tng
t, song thng c iu khin nh c cu cam dn ng trc tip t cam
nh v ca cn chn s.
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2.2 Cc loi ly hp kha lm vic trong du
Ly hp kha Trong t hp ca HST chng ta thng gp Ly hp kha dng cho HSHT: loi nay c s lng ty theo s truyn lc ca CCHT trn xe. Dng thng gp ca ly hp kha l: + Kha mt b phn ca CCHT vi nhau to nn lin kt cng quay vi tc nh nhau. Ly hp kha cho BMTL: loi ny c tc dng kha gia bnh B v bnh T khi s vng quay nT gn bng nB. C hai loi ny u dng p lc du iu khin.
a. Cu to ly hp kha hai b phn vi nhau
Ly hp kha dng dng ly hp ma st nhiu a lm vic trong du, hot ng bng p lc du ca h thng thy lc iu khin. Cu to ca b ly hp kha gm cc a ma st c rng trong v ngoi. Cc a ma st rng trong gn vi phn thn trong ca mt b phn ny, cn cc a ma st rng ngoi gn vi mt b phn khc v to nn v ca ly hp. Trn t c hai dng ly hp kha n v ly hp kha kp. + Dng ly hp kha n Cu to chung nh hnh 1-15a, cc chi tit ca mt ly hp dng ny trn t NISSAN BLUBIRD hnh 1-15b. Cc a ma st c b tr thnh cp gia cc a rng trong v a rng ngoi, kha gia trc v v ly hp. Cc a xen k nhau: mt a bng thp chu mi mn v mt a c b mt ma st lm bng vt liu atbet hay bng hp kim gm s. Ly hp c a p dng pittng, s dng vnh khn cao su bao kn. Khng gian gia v ly hp v a p to nn bung cha du. a p lun b l xo dng a hoc tr y ra khng p a ma st, cu trc ly hp thng m. a p p cc a ma st bng lc du cp vo bung cha du nh mt ng dn du. Vic iu khin du thng qua van con trt ring nm trong h thng du iu khin cc phn t kha. Khi ly hp m, ng dn du khng c p sut l xo y a p ra to nn khe h nh gia cc a ma st 0,1 - 0,05mm. Hai phn t ca CCHT c tch khi nhau (trng thi m). Khi c p sut du iu khin, a p di chuyn: ban u thng lc l xo, sau p cc tm ma st vo vi nhau to nn trng thi ng ly hp. Hai phn t ca CCHT c kha vi nhau. Khi p sut du nh lc ca l xo p y du tr v h thng cung cp v m ly hp. Qu trnh ng m xy ra rt nhanh, trong qu trnh ny lun c c hin tng trt v sinh nhit, ng thi v th tch khoan cht lng ln cc qu trnh np du v x du thng gy nn bin ng p sut. Do vy m bo iu khin nhanh v m du ly hp kha trn ng du iu khin c th c thm cc bung tch nng gim chn.
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Hnh 1-15 Cu to chung v cc chi tit chnh ca cc ly hp dng n
a) Cu to chung b) ly hp kha dng n trn NSSAN BLUBIRD
+Dng ly hp kha kp thng gp trn t bao gm hai ly hp lp lin theo chc nng lin hon ca h thng iu chnh CCHT. Khi mt ly hp ny m th ly hp khc s l ng. S cu to ca ly hp v qu trnh iu khin trnh by trn hnh 1-16. Cu to mt ly hp kha dng trn t con ca hng FORD trn hnh 1-17. Cc rng cu a y l dng ch nht (trn mt s xe khc c th rng thn khai, hay trn), cc a c th di chuyn nh nhng trn rnh khi khng c lc p. Ly hp c hai b mt ta: mt c nh, mt di ng theo a pittng p. to iu kin lp rp b mt ta c kha bi vng kha. Trong ly hp s dng l xo tr v l xo mng, khi p sut du nh c th tch cc a ma st. Khi m ly hp, di tc dng ca l xo cc tm ma st tch ra, ng thi y du ra khi khong lm vic.
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Hnh 1-16 S cu to v qu trnh iu khin ca ly hp kp
a) S cu to ; b) Qa trnh iu khin
b) t- thi gian ; p p sut du iu khin ; 1,2 cc ly hp
Trn cc pittng p c cc vnh khn bao kn, m bo pittng di chuyn v bao kn du c p sut. Cc tm ma st khi m ly hp c khe h nh khong 0,15mm, trong qu trnh s dng khe h ny tng ln, lm chm qu trnh iu khin, t chuyn ng b rung git, cn thit thay th kp thi. Kt cu khng cho php iu chnh nh trong ly hp chnh.
Hnh 1-17 Cu to cc chi tit chnh mt ly hp kha ca hng FORD
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b. Ly hp kha vi v hp s Trn HSHT ly hp kha mt phn t ca CCHT vi v hp s c hai dng cu trc:
*Cc a c rng ngoi n khp trc tip vi v hp s v ng yn.
Hnh 1-18 Cu to ly hp kha vi v ca SUBARU
+ Cc a c rng ngoi n khp thng qua v ca b ly hp, v ny c c nh
trn v hp s. Kiu ny thng gp trong kt cu, v n c kh nng to iu kin
bao kn khoang du iu khin tt hn. Trn hnh 1-18 l cu to ca 2 ly hp kha
vi v ca hai b truyn s li v s thp ca hp s t ng t SUBARU.
2.3 Cc khp mt chiu
Khp mt chiu Khp mt chiu trong HSHT b tr bnh dn hng ca BMTL, hay trong c cu iu khin ca CCHT. Tc dng ca khp mt chiu l nhm xc nh mt chiu quay gia cc phn t c chuyn ng tng i vi nhau. Trong BMTL khp mt chiu to iu kin cho bnh D quay khng truyn ti na. Trong HSHT khp mt chiu lm tt chc nng ca phn t iu khin trong qu trnh chuyn s, hoc to iu kin gim bt s sai lch vn tc gc gia cc phn t c chuyn ng tng
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i. Do vy khp mt chiu thng ng song song vi ly hp kha lm nhim v ca c cu an ton trnh qu ti cho ly hp kha. Khp mt chiu c cc dng cu to sau:
- Dng cam
- Dng bi
- Dng tr
a. Khp dng cam
Khp mt chiu dng cam gm hai vnh tr ng tm, mi vnh tr ni vi mt chi tit khc nhau c chuyn ng tng i. Gia hai vnh tr ny t cc cam hnh v nghing ta trn l xo. Cam nm trong vng cch v nh v nh l xo. L xo lun c xu hng y cam nm nghing theo mt chiu nht nh to nn s tip xc gia cam v cc vnh tr. V tr ca cam cho php khp mt chiu lm vic trng thi khng chu ti hoc chu ti. Trong HSHT cc vnh cam trong v ngoi c lin kt rt a dng. Mt kt cu tiu biu m t trn hnh 1-19a.
Hnh 1-19 Cu to cc trng thi lm vic ca khp dng cam
a) Cu to ; b) trng thi cam chu ti ; c) trng thi cam khng chu ti
Khi vnh trong v ngoi cng tc hoc vnh trong c tc ln hn vnh ngoi (theo chiu kim ng h), khp trng thi khng chu ti (h.1-19b). Khi xut hin s chuyn ng tng i (vnh ngoi quay nhanh hn vnh trong), vi tc dng ca l xo t v lc ma st ca u cam vi cc vnh cam, cam xoay theo hng
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chn v kha hai vnh tr li vi nhau, khp trng thi chu ti (h.1-19c). Nu mt trong hai vnh tr nm trong chi tit c nh vi v, trong trng hp ny chi tit cn li s b kha ng yn. Nu c hai vnh cam u nm trn chi tit quay th chng s quay cng tc .
b. Khp dng tr
Loi khp ny gm mt vnh tr trong trn v mt vnh ngoi c mt chm cong theo hng to nn chiu rng c bi thay i. Cc vin bi tr nm trong rnh chm ny v lun lun c t bng cc l xo t khc nhau. Cu to c by trn hnh 1-20.
Hnh 1-20 Cu to khp mt chiu dng tr
Nguyn l lm vic ca n cng tng t nh khp mt chiu dng cam. Khi cc vin bi chy vo ch hp to nn trng thi kha. S dch chuyn ca vin bi ph thuc vo chiu quay, chiu nghing ca mt chm tc l ph thuc vo lc ma st tc dng vo vin bi. Khp mt chiu dng tr trn t c cc dng sau:
- Vin bi t t do, vic kha hoc m khp ph thuc vo lc ly tm tc
dng vo vin bi.
- Vin bi nm trong rnh chm v c t bi cc l xo c lp.
- Vin bi nm trong rnh chm v c t bi mt l xo chung.
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Hnh 1-21. Cu to khp dng tr t trn bnh D ca BMTL
Trn hnh 1-21 l cu to khp mt chiu dng tr t trn bnh D ca BMTL.
Ch :
Cc khp mt chiu u c kh nng chu qu ti trong thi gian ngn, nu ko di thi gian qu ti s dn n tnh trng ph hng b mt cam, mt kh nng lm vic. Khp mt chiu dng bi cn t dung trong HSHT v kh nng chu ti thp. Khp mt chiu l phn t t ng iu khin, c nhy rt cao. Kh nng kha hay m ph thuc vo gc nghing mt chm, khi tho lp cn kim tra nhn bng ca b mt lm vic.
2.4 C cu kha trc b ng
C cu kha trc b ng ca hp s l c cu an ton khi t ng yn ti ch. Kha trc b ng lm vic khi cn chn s v tr P (Parking). Do tc dng m bo an ton ca n nn kha trc b ng khng tham gia vo vic thc hin cc s truyn ca HSHT. a s cc t dng c cu kiu cc hm, mt s t khc t phanh di. Trn hnh 1-22 l c cu kha trc b ng kiu cc hm ca t FORD vi CCHT kiu RAVIGNEAUX. Trn hnh 1-23 l cu to ca c cu kha trc b ng ca t NISSAN v SUBARU. Trn hnh 1-24 l cu to ca c cu kha
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trc b ng ca t MERCEDES. Cu to ca kha trc kiu cc hm bao gm: vnh rng ngoi t trn trc b ng ca hp s, cc hm c m t vo vnh rang v c th xoay quanh trc nh.
Hnh 1-22. Cu to c cu kha trc b ng ca FORD.
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Hnh 1-23.Cu to c cu kha trc b ng ca NISSAN v SUBARU.
Hnh 1-24. Cu to c cu kha trc b ng ca MERCEDES.
Cc hm lun trng thi m bng l xo, mt con trt dng cam thc hin ng m cc hm i trt trn trc v c iu khin bi cn chn s thng qua dy cp, trc quay v n xoay. C cu ny c iu chnh cng vi vic iu chnh cam quay nh v ca cn chn s. C cu kha trc b ng HSHT l c cu an
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ton ca t trng thi , ngi li c th ri khi xe m t khng xy ra hin tng t b (trong quy nh s dng ca cc hng vn cn phi ko phanh tay). Mt khc khi xe ang chuyn ng khng c php t cn chn s vo v tr P. Ti v tr ny, khi xe cn ln bnh, s xy ra hin tng kha trc b ng t bin v c th gy nn qu ti cho HTTL, hay xe b quay ngot bt ng nguy him.
2.5 H thng van
Thn van bao gm mt thn van trn v mt thn van di.
Thn van ging nh mt m cung gm rt nhiu ng dn du hp s chy qua.
Rt nhiu van c lp vo cc ng dn , trong cc van c p sut thu lc iu khin v chuyn mch cht lng t ng dn ny sang ng dn
khc.
Thng thng, thn van gm:
Van iu p s cp
Van iu khin
Van chuyn s (1-2, 2-3, 3-4)
Van in t (s 1, s 2)
Van bm ga
Van iu p th cp
S lng van ph thuc vo kiu xe, mt s kiu xe c cc van khc vi cc van nu trn.
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2.5.1 Van iu p s cp:
a. Vai tr ca cc b phn Van iu p s cp iu chnh p sut thu lc (p sut c bn) ti tng b phn ph hp vi cng sut ng c trnh tn tht cng sut bm. b. Hot ng: Khi p sut thu lc t bm du tng th l xo van b nn, v ng dn du ra ca x c m, v p sut du c bn c gi khng i. Ngoi ra, mt p sut bm ga cng c iu chnh bng van, v khi gc m ca bm ga tng ln th p sut c bn tng ngn khng cho li hp v phanh b trt. v tr R, p sut c bn c tng ln hn na ngn khng cho li hp v phanh b trt.
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2.5.2 Van iu Khin Van iu khin c ni vi cn chuyn s v thanh ni hoc cp. Khi thay
i v tr ca cn chuyn s s chuyn mch ng dn du ca van iu
khin v cho du hot ng trong tng v tr chuyn s.
Ni chung cc cp c s dng trong cc xe FF (ng c ng trc, dn ng bnh trc) v thanh ni c s dng trong cc xe FR (ng c ng
trc, dn ng bnh sau).
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2.5.3 Van Chuyn S
a. Vai tr ca cc b phn Ta chuyn s bng cch thay i s vn hnh ca cc li hp v phanh. Cc van chuyn s chuyn mch ng dn du lm cho p sut thu lc tc ng ln cc phanh v li hp. C cc van chuyn s 1-2, 2-3 v 3-4. b. Vn hnh V d: Van chuyn s1-2 Khi p sut thu lc tc ng ln pha trn van chuyn s th hp s c gi s 1 v van chuyn s di cng v cc ng dn du ti cc li hp v phanh b ct. Tuy nhin, khi p sut thu lc tc ng b ct do hot ng ca van in t th lc l xo s y van ln, v ng dn du ti B2 m ra, v hp s c chuyn sang s 2.
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2.5.4 Van in T
Van in t hot ng nh cc tn hiu t ECU ng c & ECT vn hnh cc van chuyn s v iu khin p sut thu lc. C hai loi van in t. Mt van in t chuyn s m v ng cc ng dn du theo cc tn hiu t ECU (m ng dn du theo tn hiu m, v ng li theo tn hiu ng). Mt van in t tuyn tnh iu khin p sut thu lc tuyn tnh theo dng in pht i t ECU. Cc van in t chuyn s c s dng chuyn s v cc van in t tuyn tnh c s dng cho chc nng iu khin p sut thu lc.
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2.5.5Van Bm Ga Van bm ga to ra p sut bm ga tu theo gc ca bn p ga thng qua cp bm ga v cam bm ga. p sut bm ga tc ng ln van iu p s cp, v nh vy s iu chnh p sut c bn theo m ca van bm ga. Mt s kiu xe iu khin p sut bm ga bng mt van in t tuyn tnh (SLT) thay cho van bm ga. Cc kiu xe nh vy iu khin p sut bm ga bng ECU ng c & ECT chuyn cc tn hiu ti van in t tuyn tnh theo cc tn hiu t cm bin v tr van bm ga (gc m bn p ga).
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2.5.6 Van iu p th cp Van ny iu chnh p sut b bin m v p sut bi trn. S cn bng ca
hai lc ny iu chnh p sut du ca b bin m v p sut bi trn.
p sut b bin m c cung cp t van iu p s cp v c truyn ti van rle kho bin m.
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a. Van ngt gim p Van ny iu chnh p sut ngt gim p tc ng ln van bm ga, v c
kch hot do p sut c bn v p sut bm ga. Tc ng p sut ngt gim
p ln van bm ga bng cch ny s lm gim p sut bm ga ngn
nga tn tht cng sut khng cn thit t bm du.
b. Van iu bin bm ga
Van ny to ra p sut iu bin bm ga. p sut iu bin bm ga hi thp hn so vi p sut bm ga khi van bm ga m to. Vic ny lm cho p sut iu bin bm ga tc ng ln van iu p s cp cho cc thay i trong p sut c bn ph hp hn vi cng sut pht ra ca ng c.
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c. B tch nng B tch nng hot ng gim chn ng khi chuyn s. C s khc bit v din tch b mt ca pha hot ng v pha sau ca piston b tch nng. Khi p sut c bn t van iu khin tc ng ln pha hot ng th pt tng t t i ln v p sut c bn truyn ti cc li hp v phanh s tng dn. Mt vi kiu iu khin p sut thu lc tc ng ln b tch nng bng mt van in t tuyn tnh s qu trnh chuyn s c m du hn.
2.5.7 Cc Van Khc Van rle kho bin m v van tn hiu kho bin m Cc van ny ng-m kho bin m. Van r-le kho bin m o chiu dng du thng qua b bin m (li hp kho bin m) theo mt p sut tn hiu t van tn hiu kho bin m. Khi p sut tn hiu tc ng ln pha di ca van rle kho bin m th van rle kho bin m c y ln. iu ny lm m ng dn du sang pha sau ca li hp kho bin m v lm cho n hot ng. Nu p sut tn hiu b ct th van rle kho bin m b y xung pha di do
p sut c bn v lc l xo tc ng ln nh van rle, v s m ng dn du
vo pha trc ca li hp kho bin m lm cho n c nh ra.
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2.6 Cm bin
2.6.1 Cm bin v tr bm ga : - Cm bin ny c gn trn bm ga v cm nhn bng in mc
m bm ga sau n gi nhng d liu ny n ECU (di dng tn
hiu in) iu khin thi im chuyn s v kha bin m.
- Kiu dn tip
- A140E l kiu m ECU ng c c gn gia v tr cm bin bm
ga ECT ECU nh hnh v di.
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- Cm bin v tr bm ga bin i mt cch tuyn tnh lc m bm ga thnh
cc tn hiu in. Mt in p khng i 5V c cp n in cc Vc t
ECU ng c.
- Khi bm ga trt dc in tr theo gc m bm ga in p tc dng ln
cc Vta t l vi gc ny.
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- ECU ng c bin i in p VTA thnh mt trong 8 tn hiu gc m
bm ga khc nhau bo cho ECT ECU bit gc m ca bm ga.
- Nhng tn hiu ny bao gm cc tp hp khc nhau ca cc in p cao v
thp ti cc L1, L2, L3 hoc IDL ca ECT ECU nh bng di.
- Khi bm ga ng hon ton, tip im cho tn hiu IDL vi cc E, gi tn
hiu n ECT ECU bo rng bm ga ng hon ton.
- Sau khi ECT ECU nhn c cc tn hiu L1, L2, L3 v IDL, n thay i
gc m ca bm ga thnh in p t 0V n 8V bo cho k thut vin
bit gc m ca bm ga pht ra t cc TT c c a vo mt cch bnh
thng hay khng.
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2.6.2 Cm bin nhit nc lm mt: Khi nhit nc lm mt thp hn nhit xc nh, tnh nng ca ng c v kh nng ti s gim nu hp s chuyn ln t s truyn tng. trnh hin tng ny, cc tn hiu c nhp vo ECU ngn khng cho n chuyn ln t s truyn tng trc khi nhit nc lm mt t n nhit xc nh.
Cm bin ny cm nhn nhit nc lm mt nh mt nhit in tr, bin n thnh cc tn hiu in v gi cc tn hiu ny n ECU ng c.
Nu nhit nc lm mt gim xung di mt nhit xc nh (tc 60) ECU ng c gi tn hiu n OD1 ca ECT ECU, ngn khng cho hp s chuyn ln O/D v ly hp kha bin m hot ng.
mt kiu xe ngn khng cho chuyn ln s 3 ti thi im ny.
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ECU ng c bao gm chc nng d phng: Nu cm bin nhit nc lm mt hng do h hay chp mch, ECU ng c s iu khin vi gi thit nhit nc lm mt l 800C, m khng ph thuc vo nhit nc lm mt thc t.
2.6.3 Cm bin tc :
m bo rng ECT ECU lun nhn c thng tin ng v tc bnh xe, cc tn hiu c nhp vo ECT ECU nh 2 cm bin tc . t c chnh xc hn na, ECT ECU lin tc so snh tn hiu ny xem chng c ging nhau hay khng.
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Cm bin ny c gn trong ng h tc v hot ng thay th cm bin tc chnh nu n b hng. N sinh ra 4 xung cho mi vng quay ca dy cng t mt.
Ch :
Nu c 2 tn hiu tc u ng, cc tn hiu t cm bin s 2 c s dng iu khin thi im chuyn s sau khi so snh vi tn hiu vi cm bin s 1. Nu tn hiu t cm bin tc s 2 l sai, ngay lp tc ECU khng s dng tn hiu ny m s dng cm bin t tc s 1 iu khin thi im chuyn s. N s pht ra m chun on s 62 nu hin tng ny xy ra thm vo m chun on s 42 cng c hin th nu cm bin s 1 tr nn khng bnh thng.
Cm bin tc s 2: Mt m t c gn cc nam chm bn trong c gn trn trc dn ng bnh rng ca hp s hay trc th cp. Bt c khi no trc quay c mt vng, nam chm kch thch cng tc li g (c gn trc cm bin chnh) lm n sinh ra mt tn hiu. Tn hiu ny tng ng vi p sut ly tm trong hp s iu chnh thy lc hon ton, c gi n ECU, ECU s dng n iu khin thi im chuyn s v hot ng ca ly hp kha bin m. Cm bin ny pht ra mt xung trong vng quay th cp.
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III. Kt lun v nh gi
Trong HSTD s thay i cc s truyn c thc hin nh tc ng ca ch
lm vic ca ng c v mmen cn gy nn i vi h thng thy lc. Cc cm
bin theo di lin tc qu trnh thay i trn , to nn cc tn hiu iu khin v
thng qua c cu tha hnh tc dng vo phn t iu khin ca HSHT. qu
trnh chuyn t s ny sang s khc din ra s ng (kha ) hoc m ( tch) cc
phn t iu khin tng ng cho 1 quy lut thi gian .Cc phn t m tin hnh
sm hn vic ng ca cc phn t ng, trnh trng hp c 1 thi im nht
nh hp s lm vic hai s truyn ng thi. Cc phn t ny l cc c cu ma
st lm vic trong du, m bo iu kin lm vic lu di cho php qu trnh
chuyn s nhanh, m du
Mt khc trong qu trnh chuyn s t ng, cc c cu ma st lun lm vic
trong trng thi c s trt, dn ti t nng cc chi tit. iu ny gy nn tn
tht cng sut truyn v pht sinh nhit trong cc b mt ma st .S tng cao nhit
c du truyn ra ngoi , nhng nu nng qu mc s dn ti gim nht
ca du nhn , v ph hng ch bi trn ca cc chi tit . Trn t con cc
phn t iu khin ang c lin tc hon thin, theo hng nng cao hiu qu
iu khin, gim tn tht ma st v tng bn cho cc c cu.
Cc phn t ly hp kha, phanh di, khp an ton kha trc b ng gi l phn
t iu khin trong HSHT, n m bo chc nng xc nh trng thi lm vic
ca cc b phn ca t lm vic lu ngy c th xy ra cc s c lm gim hoc
mt hiu qu iu khin, iu ny dn ti s h hng ca b truyn AT, cn tin
hnh kim tra, chun on, iu chnh theo nh k
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