Cơ sở khoa học của việc lắp đặt bộ điều hòa lực phanh trên ôtô vận tải

D8 giam thieu tai nan giao thong a Viet Nam, ngoai viec hoan thien ha tang giao thong, viec nghien cuu hoan thien ket can cae 6 to lap rap trong nuac dat ra cho cac nha khoa hgc can phai

NGHIEN cuu-TRAO 001

Cd s o KHOA HOC CUA VIEC LAP DAT BO DIEU HOA Ll/C

PHANH TREN 6 TO VAN TAI

SCIENTIFIC BASIS OF INSTALLATION OF REGULATE BRAKE

PRESSURE ON TRUCK

GS.TS Vu Diic Lap', Dumg Van Toan^

'Hoc vien ICy thuat Quan sir

^Truong Cao dSng Kinh tS - Ky thuat Vinh Phiic

TOM T A T

Trong nhirng nam gdn day, 6 td van tdi ddng vai trd rdt quan trong trong suphdt trien ctia nen kinh

te nu&c ta Viec sir dung 6 to van tdi dd ddn tra thdnh tdt yeu vd mite do su dung ngay mot gia tdng Tinh den thdng 572011, sdn luang lap rap vd nhgp khdu d td cd su tdng trudng tir 6% -10%

Vay viec nghien ciru, lap dat thiet bi dieu hod lucphanh tren xe 6 to van tdi Id rdt thiet thuc vd cdp bdch, gdp phdn ndng cao chat luangphanh 6 td vd gdp phdn gidm thieu tai nan giao thdng a Viet Nam hien nay

Tir Ichoa: Dieu hod lire phanh; Ca s& khoa hoc; O td van tdi, hieu qud phanh

ABSTRACT

In recent years, truck plays a very important role in the economic development of our country Using trucks has gradually become inevitable and the level of usage is increasing more Up to May

2011, the automobile assembly production and the automobile import grow from 6% to 10%

So the study and the installation of regulate brake pressure on truck are very practical and urgent, and contribute to improving the quality brake and reducing traffic accidents in Vietnam today

Keywords: Regulate brake pressure; Scientific basis; Trucks, brake effectiveness

I DAT VAN DE Cac doanh nghiep san xu4t lip rap 6 to tren

Hien nay, nhn cong nghiep 6 to cua Viet Nam co so cac cong ty co khi qu6c doanh: Cong ty C6

CO ban g6m 3 thanh phSn: Ph^n Co khi 6 to Hoa Binh; Cong ty 6 to 1-5, Cac cong ty 6 to hen doanh: Toyota Viet Nam; " "S ty O to 3-2

Ford Viet Nam; Vidamco; Nissan; Honda Cac doanh nghiep tu nhan: Doanh nghiep Tu '

TAP CHi CO KHl VIET NAM, S6 3 nam 2014

NGHIEN CUV-TRAODOI

nhan Vinaxuki; Cong ty 6 to Truong Hai; Cong

ty 6 to Chien Thang

Theo danh gia cua eac chuyen gia, tuy

nganh cong nghiep 6 to co toe do tang truang

manh me nhung quy mo con khiem ton Trong

b6i canh thi truang 6 to the giai rai vao khung

hoang, san lugng 6 to tieu thu giam siit manh

nhung nganh 6 to Viet Nam dugc danh gia da

vugt qua thai ky khiing hoang va co su phat

triln kha 6n dinh Tinh den thang 5/2013, san

lugng lap rap va nhap khau 6 to co sir tang

truang tir 6% - 10%

D8 giam thieu tai nan giao thong a Viet Nam,

ngoai viec hoan thien ha tang giao thong, viec

nghien cuu hoan thien ket can cae 6 to lap rap

trong nuac dat ra cho cac nha khoa hgc can phai

nghien cuu nang cao chat lugng 6 to noi chung va

chat lugng phanh noi rieng

Vay, viec nghien cuu, lap dat thiet bi dieu hoa

lue phanh tren xe 6 to van tai la rat thiet thuc va

cap bach, gop phan nang cao chat luong phanh

6 to va gop phan giam thieu tai nan giao thong a

Viet Nam hien nay

2 KHAO SAT DAC TINH LAM VIEC CIIA

BQ BIEU HOA LlTC PHANH HAI THONG SO

Nhu chiing ta da biet, cac qua trinh phanh 6

to deu dan tai hien tugng tang tai trgng tae dung

len can truac, giam tai trgng a cau sau Su phan

bo lire phanh can thiet phai dam bao mdi quan he

giija mo men phanh sinh ra a chu phanh (hay lue

phanh sinh ra a banh xe) ty le vai phan luc thSng

dung tac dung len cae banh xe Thuc hien dugc

yen cau nay se nang cao chat lugng phanh, giam

mai mon lop, tang kha nang dieu khiin xe va nang

g TAP CHi CO KHi VIET NAM, S6 3 nam

www.cokhivietnam.vn

cao an toan chuyin dgng (han che trugt ngang cau xe) Bg diSu hoa luc phanh la mgt trong cac ket c4u bd tri tren xe nh5m thuc hien muc dich nay Trong ngi dung bai nay, chung toi ehi de ca,p tai bg dilu hoa lure (BDH) phanh hai thong so

-uy

BDH

(C, C2, D, d }

Hinh 2.1: Sa dd cdu true hi thdng diiu chinh luc phanh BDH hai thdng sd:

T: Hi thdng treo; A: O td; TP: Tdng phanh

Nhin vao sa do cau true tren hinh 2.1, ta thay BDH luc phanh khong chi dugc dieu khien bai ap

suat p^ tu tong phanh ma no con dugc dieu khien theo tai trgng F^ Trong qua trinh phanh, tai trpng

tren eau sau thay doi dan den lue tac dgng len

piston BDH lam thay doi ap suat rap^ phu hgp vcri

sir thay doi tai trpng tren eau sau khi phanh

Hinh 2.2: Ket cdu vd sa do nguyin ly ciia BDH luc phanh hai thdng sd

Tren hinh 2.2 the hien cu thi vl kit ciu va

sa d6 nguyen ly lam viec eua BDH luc phanh hai thong s6, gom mgt so chi tiet ca ban nhu sau: 1)

2014

NGHIEN ciru-TRAO DOI

Piston; 2) Vach ngan; 3) Vanh ty; 4) Xilanh; 16 xo

1; 16 xo 2 va cac chi tilt khac

Khi chua phanh, 16 xo 1 va ca cau dan dgng

n6i chu sau vai BDH dky piston sang ben phai ty

sat vao v6 cua bg Dieu hoa Liie nay, du6Tig dau

thong til tong phanh ra xilanh phanh banh sau, ap

suat dau trong dan dgng phanh: Pj=p^= p^^

Khi phanh, ta xet 2 giai doan:

+ Giai doan T Ap suat dau trong dan dgng

tang t i r / 7 = ; 7 ^ d i n ;;„

Do ket cau cua BDH luc phanh co khe ha 5

nen khoang A thong vol khoang B, ap suat dau

trong dan d6ng toi xi lanh phanh truoc va xilanh

phanh sau la bang nhau^^ = p^ ^ p Khi ap suat

p tang den mgt gia tri p ' nao do, vai p ' < p^ cong

voi sir chenh lech dien tich cac bac cua piston thi

piston se bi dich chuyen sang trai mgt khoang /

so voi vi tri ban dau, dong thai do co su giam tai

trgng cua c i u sau khi phanh lam cho piston cua

BDH dich sang trai them mgt khoang / \ Khi do

phuong trinh can bang lire doi voi piston a trang

thai can bang la:

7rd^

Fx=P — + F^2(2.1)

Trong do:

F^ La luc nen cua c a c i u d i n dpng BBH a vi

tri dang phanh:

F^=C^.(l, + l-rj(2.2)

Cy, Do Cling cua co c i u d i n dong BDH;

; : Dp biSn dang ban d i u cua 16 xo co cau d i n

dpng;

F,^^: Luc d l y cua 16 xo 2 (ngupc chi6u vdi

fia = C/l,,-l-rj(2.3)

C : Do cung 16 xo 2;

TAP

/,„: Do bien d I ban dau cua 16 xo 2 Khi tiep tuc dap phanh, ap suat p tang tai gia tri p^, piston BDH tiep tuc dich chuyen sang trai

eho tai khi vai ciia piston cham vao vach ngan

khe ho S = 0, ngan each khoang A vai khoang

B Liic nay, khoang B tra thanh khoang kin: Tir van dieu chinh ap suat tai xilanh phanh banh sau Khi do ap suat trong khoang A bang ap suat trong khoang B va bang ap suat lam viec p^ cua BDH:

Pl^P2=Po + Giai dogn 2: Giai doan lam viec cua BDH,

ap suat dau trong d i n dgng tiep tue tang (p^ > p^

- Khi ap suat/?, tiep tuc tang, piston ciia BDH

bi day dich sang trai, tach vach ngan ra khoi vanh

ty Phuang trinh can bang lire doi vai piston a trang thai nay la:

Trong do: F\: la luc nen ciia ea eau din

dgng BDH a vi tri mai

F'^=C/l^ + l'-l"J (2.5) T: La khoang dich chuyen ciia piston a trang

thai mai;

l"^ La khoang dich chuyen cua piston do su

giam tai gay ra a trang thai mai;

F^^i La luc nen ciia 16 xo 1:

^,„ = C//,„ + / - - < 5 - / V (2.6) l^g: La bien dang ban dau ciia 16 xo 1; F'j^^: La luc nen cua 16 xo 2

P'i.2 = Cfi„^r-l"J (2.7)

Quan he ap suat trong xi lanh banh xe ciu tnrac vdi xi lanh banh xe cau sau trong qua trinh phanh:

4 4 -' Tir cong thiic (2.4) d i n (2.8) ta xac dinh dugc ^

CHi CO KHi VIET NAM, S6 3 nam 2014

NGHIEN ciiu-TRAO001

phuang trinh dac tinh lam viec ciia BDH hai

thong so:

' Pi^Pi ^^^Pi^Po

p,-Ạp, + B.[F\+F^^-F\Jkhip>p^

Trong do: ^, B: La cac he so ket cau ciia BDH:

4

Dt'Dt

Dl-Dt .B = - KiDl-D;)

C^: La do cung ciia ca cau dan dgng BDH;

C,, C, - la do Cling ciia 16 xo 1,16 xo 2 ciia BDH;

D , D^- la duong kinh xi lanh, piston eua BDH;

d: La du6ng kinh than piston BDH

P,„x P,

Hinh 2.3: Dd thi dgc tinh Idm viec cua BDH hai

thdng sd

+ Duong 1: La dac tinh thuc te (xe khong co

BDH);

+ Duong cong Oae: La dac tinh ly tuong cua

BDH khi xe khong tai;

+ Duong gap khiic 2: La dac tinh lam viec

eiia BDH khi xe khong tai;

+ Duong cong Obg: La dac tinh ly tuong cua

BDH khi xe diy tai;

+ Du6ng gip khiic 2': La dac tinh lam viec

eua BDH khi xe dky tai;

+ Diem a, b la diem bat dau lam viec cua

BDH khi xe khong tai va day taị

* Xac dinh khoang dich chuygn /' va /« ciia piston

- Tinh / "^: Khi phanh co su giam tai a ck

sau lam thay doi khoang each / giiia san xe va

v6 chụ Su thay d6i nay thong qua bg phiin dau

h6i ciia BDH (16 xo ca c4u din dgng) lam piston

BDH dich chuyen mgt khoang r\ ^ i^j-f 6 dayi^

la he s6 dku dgng cua 16 xo din dgng BDH

Khoang cach/dugc xac dinh theo cong thiic:

_G.a-g,.L PA

L.C,.,

/ • =

L.C., (2.9)

C

Ci day: g^ Trpng luang phSn khong dupe treo; ,: Do Cling tong cong he thong treo cau sau; P: Luc quan tinh cua xe khi phanh

Gia toe cham dan j cua xe khi phanh dat duoc gia tri lan nhat la liic sii dung luc bam Ion nhat:

-(p.g = (p.a = P G.a-g^.L ip.GJi^

(2.10)

Neu coi h ^ la khong doi khi phanh thi:

f=A,-ẬV (2.11)

Vai:

G.a-g,.L G.h^

(2.11)

Tir cong thiic (2.11) ta tinh dupe dp vong/ ciia he thong treo cau sau khi khong tai va khi cM day taị Tinh dp vpng cho cac diem A, Á, B, B'

tuang ling voi cac gia tri ^^ tp^., ip^ ta dupe:

G„.a-g,.L ip,-GẠ

G„.a-g^.L <P -GA L.C., ịẹ, TAP CHI CO KHI VIET NAM, So 3 nam

www.cokhivietnam.vn

2014

f,- =

G.a

LC,, L.C^,_ •

Gn-g^.L <P,.-G.h^

L.C pi Mat khac, can eii theo quan he p^ — f(p),

ling vai moi gia tri he so bam (p^^(p^.,(p^ ta tim

dupe mpt ap suat p^ tuang irng T u do ta se xay

dung duoc do thi quan he giira ap suat phanh p^

theo dp v o n g / hay chinh la su phan bo lai tai

trpng khi phanh

^01 I Olmax

Hinh 2.4: D6 thi quan he giita p,vdf

+ Phuang trinh duong B B ' :

J SB U-f, ^L-p ' -/B' JB

^f„=PrB,-^3^(2.12)

Ciday:

B,= JB' JB

B,

Pi

f.-p\

,.-P

U-IB

'?,.„.-p

H Phuang trinh duang AA':

(2.13)

(2.14)

hzl^ ^fA-P\ L L

Po„:

^ f^-=PrH, + H,(2.15)

L-.L

p l

H2=f„~P\

ay ta c6:

, 2.16

„-Pm

L'-L

(2.17) Pm.n„-Pm

r\ = ij(2.i8)

Do vong / trong tir truong hgp khong tai hay day tai dugc xac dinh theo cong thiic (2.12) va (2.15)

- Tinh r : r : La khoang dich chuyen cua piston

sang trai khi khong ke den su giam tai trgng cua cau sau khi phanh Ggi AF la chenh lech luc tac dung giiia hai phia cua piston van dieu hoa, khi do:

\p.^*P

Trong

^,.w =

^ ' • = c c

a day:

M.=It{D]

-4

do:

Cfl,

^F = k.l^^

°''.^ „]-[., ^"'•;''"'

^''-S):F;,, = C,(1,„

+ * 4 4

-^/

1

= P,.M^ +p,.M, + M^

7[(D;~Dl + dl)

,] =

+ ' • ;

.-c,«

(2.19)

{2 7n

kr

S)J

M,

C,+C,+k

1 JC01-DI)

M,

C,-i-C,-i-jt

1

(2.21)

C,+C,+k .C,J,,-C,(1,„-S)(2.22)

Khi xac dinh dupe / ' va /"^ thi ta se xac dinh dupe phuang trinh mo ta hoat dpng cua BDH o trang thai lam viec trong truang hpp day tai hpac khong tai Cu the nhu sau:

TAP CHi CO KHi VIET NAM, So 3 nam 2014

NGHIEN ciiu-TRAODOI

phuong trinh dac tinh lam viec cua BDH hai

thong so:

P2^P, ^^^Pj^Po

^p^=A.p^+B.[F\+F,^-F'Jkhip>p„

Trong do: A, B: La cac he so ket cau cua BDH:

4

DI-D; .B =

D'^-D'^ • 7V{D;-Dl)

C^: La dp Cling ciia ca cau dan dgng BDH;

C,, C-, - la do Cling cua 16 xo 1,16 xo 2 ciia BDH;

D^, D^- la duong kinh xi lanh, piston cua BDH;

d: La duong kinh than piston BDH

PPl , Po,™x P,™ P,

Hinh 2.3 Dd thi dgc tinh lam viec cua BDH hai

thdng sd

+ Duofng 1: La dac tinh thirc te (xe khong co

BDH);

+ Duong cong Oae: La dac tinh ly tuong ciia

BDH khi xe khong tai;

+ Duong gap khiic 2: La dac tinh lam viec

ciia BDH khi xe khong tai;

+ Duong cong Obg: La dac tinh ly tuong cua

BDH khi xe diiy tai;

+ Duong gap khiic 2': La dac tinh lam viec

ciia BDH khi xe dky tai;

+ Diem a, b la diem bat dau lam viec cua

BDH khi xe khong tai va dky tai

B B TAP CHi CO KHi VIET NAM, S6 3 nam 2014

www cokhivietnam.vn

* Xac dinh khoang dich chuyen /' va / "^

cua piston

- Tinh / "^: Khi phanh co su giam tai 6 cSu

sau lam thay d6i khoang each/giiia san xe va v6 cau Sir thay doi nay thong qua bo phan dan h6i ciia BDH (16 xo ca cau din dgng) lam piston

BDH dich chuyen mgt khoang / "^ = i^J' 6 day i

la he s6 dSn dgng ciia 16 xo ddn dgng BDH Khoang each/duoc xac dinh theo cong thiic'

O day: g,.Trgng lugng phan khong dugc treo;

C ^: Do cimg tong cong he thong treo eau sau; P:

Luc quan tinh cua xe khi phanh

Gia toe cham dan j cua xe khi phanh dat diroc gia tri Ion nhat la liic sir dung luc bam lan nhSt:

J,u^^

'PS-Neu coi h la khong doi khi phanh thi:

f=A,-A^,p (2.11)

Vai:

GM, ' L.C -(2.11)

Tu eong thiie (2.11) ta tinh dupe dp vong/ eiia he thong treo cau sau khi khong tai va khi chff day tai Tinh dp vpng cho cae diSm A, A', B, B'

tuang ling voi eae gia tri tp^^ tp^., ip^ ta dupe:

_G,.a-g,.L <P,.GA

G a

L.C,-,

L.C,-L.C,.,

NGHIEN cuu-TRAODOI /

IB'

_G.a-g^.L P '

G.a-g,.L <I>,.G.\

Mat khac, can cii theo quan he /7, - f(p),

irng vol moi gia tri he so bam (p^(p^.,tpg ta tim

dupe mpt ap suat/?, tuang ling Tir do ta se xay

dung dupe do thi quan he giiia ap suat phanh p^

theo dp vong/ hay chinh la su phan bo lai tai

trpng khi phanh

*'01 ^1 ^^Olmax

Hinh 2.4: Do thi quan he giiia p^ vdf

+ Phugng trinh duong BB':

fiA' = P>

<^ f^ = p,.H,+H,(2.15)

Vai:

fA'-.f,

H, = /

ay ta co:

Pc.i„

-p\

„-p\ (2.16)

^ ' \ (2

-Pm 17)

I" =ij(2.18)

Do vong / trong tir truang hgp khong tai hay

day tai dugc xac dinh theo cong thiic (2.12) va (2.15)

- Tinh 1': r: La khoang dich chuyen ciia piston

sang trai khi khong ke den su giam tai trgng cua

cku sau khi phanh Ggi IsF la chenh lech luc tac

dung giiia hai phia cua piston van dieu hoa, khi do:

^F = k.l'^

TTD:

-+T;, p,'

Trong do:

F,a-c,(i,„ + r-s),Fi^ = c/i,„ + r)

•' ^^.!^^^^^^*r !^*c.j.-c.tt.-S,]

^V = p,.M^ +p^.M^ + Mj (2.19)

7t{D;-Dl + d])

Oddy:

M,= 1 C,-^C,+k

1

M, K(D;-Dl)

M,

C,+C,+k

1

(2.20)

(2.21)

Khi xac dinh dugc /' va r\ thi ta se xac dinh

dugc phuang trinh mo ta hoat dgng ciia BDH a trang thai lam viec trong truang hgp day tai hoac

khong tai Cu the nhu sau: ^

TAP CHi CO KHi VIET NAM, So 3 nam 2014 H f j

NGHllN CliU-TRAO DOI

y Trudng hop xe day tdi;

„ = ° ' " 5 ' ~ , ' ' ' + 1—-[(,,,«,+p,M,+«,)(C, + C,+C,)+

'^" " D:-D; it(D;-D',y ' • '

I„(PI.S|+«,)(C,-LVC.)+C.;.+C,(/,-*)-CJ/,,]

N, N,

Trong do:

Dl-iy, iHD;-Dl)

«,=—T—T-Wii: tc,+c,)tL,B,(c, -c,

-c.)+c.;,+c,(/„-Ji-a,],-l(D,'-fl,') " • ' - " • ' •

« , = 1 — - M , { c , + c , + c , ) , •

T ( 0 ; - o ; )

Cac he s6 B,, B^, A/,, A/^ M^ da duac xae dinh

theo cac cong thiic (2.13), (2.14), (2.20), (2.21),

(2.22)

+ Trucmg hap xe khdng tdi: Tuang tu ta ciing

xae dinh duoc:

PI=PI

L, L,

Trong C

^ D:-D; t!{Dl-Dl) ' • ' " ' '^ ' ' •'•

-[M,{C,tC,*C,)*,„.ll,iC,-c,-CJtC),*Cfi,-S)-CU

Z , = i

-!i(Dl-Dl) -^M,(C., + C,+C^)

Cae he s6: //,, H^ M, M , M^ da dupe xac djnh

theo cac cong thirc (2.16), (2.17), (2.20), (2.21), (2.22)

N h u vay, vai moi bp thong so cu the cua xe va ciia BDH, ta xac dinh duac duong dac tinh diju chinh ciia BDH phu thupe vao cuong dp phanh va tai trpng trong mpi che dp tai trong ciia xe

3 NHAN XET VA KET LUAN

Qua nhimg phan tieh va su tinh toan, ta nhan thdy hieu qua diSu chinh eua BDH hai thong s6 dat dupe la kha cap, n6 c6 duong dac tinh lam viec rit g i n v6i duong dac tinh ly tuong No con cho phep diiu chinh thich hop vai mpi che do tai trpng, CO thg dimg cho eac xe co tai trpng trung binh va lan Ngoai ra, ket eau cua BDH hai thong

so tuang d6i dan gian va de che tao

Cac npi dung trinh bay tren day se la ca so khoa hpc d i tham khao khi thiet ke che tao va lap dat BDH luc phanh hai thong so tren xe o to van tai, nham nang cao chat lupng phanh va dam bao

an toan khi phanh.<*

Ngay nhan bai: 12/02/2014

Ngay phan bien: 14/3/2014

Tai lieu tham khao:

[1] VuDiJc Lap Dong luc hoc phanh d to NXB Quan dpi Nhan dan, Ha Npi, (2011)

[2] V.B Simbalin, N.N tepcjixfe" Saxi avtomobilia, Moskya (1977)

[3] P.P Lukln, G.A Gaspariens Konstrmrovanhie i rastrot avtomobilia Moskva, (1984)

TAP CHi CO KHi VIET NAM, So 3 nam 2014