Băng tải nhiều dẫn động có sử dụng băng trợ lực

Thong tin khoa hoc cong nghe mo

1^. ^ 1^1 ^Hiiy 0^1^ gg^Q QQ SlT DUNG BANG TRa LlTC

In many recent years, for increasing the working length\

of the belt conveyors, the theoretical researches and

Improvement of the designing works for manufacturing

of a conveyor with multi drive systems using power

belts have been carried out widely on the world.

KS. NGUYEN PHI HUNG

KS. NGUYIN DLTC LINH

Cdng ty CP TVDT Md va CN- Vinacomin

I. Ly thuyet tfnh toan bang trd lure

Tfnh toan Iffc keo che bang tai cd su" dung

bang trd Iffc la ti'nh toan sff truyin Iffc keo

thdng qua ma sat giffa bang mang tai va bang

trd Iffc, cac tfnh toan tie'n hanh d trffdng hdp

phffc tap nhat. 6 giffa cac gia tri van tdc, chieu

rdng bang che trffde theo nang suat, viec tfnh

toan bao gdm: xac djnh tai (vat lieu mang tai)

phan bdtren bang mang tai; chon khoang each

giffa cac bang trd Iffc l^va chilu dai cQa bang

trd Iffc Ibt; xay dffng gian dd liic cang cCia bang

mang tai va bang trd Iffc; xac djnh IL/C keo cang

va tfnh cdng suat ddng cd dan ddng. Gia djnh

bang lam viec treng dieu kien xau nhat, khi dd

he sd ma sat giffa bang mang tai va bang trd

Iffc f=0,3.

He sd can trd chuyin ddng co' trong trffdng

hdp nay chon theo cac gia tri chung nhff ddi vdi

bang tai thdng thffdng.

Chilu dai bang trd Iffc trong bang tai cd suf

dung bang trd Iffc can phai tinh sao cho khdng

cd sff trffdt trdn d mpi trang thai mang tai cilia

bang mang tai. Tren mdi bang trd Iffc phai thoa

man dilu kien: Ldh<ltx C)

Chilu dai phan trffdt dan hdi U cd th i tim

dffdc tff dieu kien can bang cac Iffc tac dung

len bang trd Iffc. Khi mang tai day, dieu kien

nay la:

M„ -- L (lb, + ?*„, )(ffl'. cos y9 ± sin /?) + (/„ - Ij^ )(?j„, + ?i, + ? + q„ >

E,+E,

L (?»» + ?)/] cos ^ ± Lit, sin ^ , kG (2)

Trong dd:

qb„„ bb,: Trong Iffdng phan bd cua bang

mang tai va bang trd Iffc;

Ebm, Ebt: Md dun dan hdi cCia bang mang tai

va bang trd Iffc;

Mdci Mdmen tTnh ciia ddng cd dien;

R: Ban kfnh tang dan ddng.

Trffdng h(3p sCf dung cd gidi han kha nang

keo cCia bang trd Iffc lbt=lb<- Trong trffdng hdp

nay khi dung cdng thffc (2), ta se cd:

M,.,

L

(q + q)f COSp + (q,„ + q„ + q^,'+ q^, ")co'COSP

(3)

Nhff vay, chilu dai yeu cau Ibt phu thudc vao

md men do ddng cd dien tao ra va md men dat

cffc dai dd tai d tat ca cac khoang, chi trff mot

trffdng hdp, trffdng hdp nay:

M. W,,(«-l) + W„

R (4)

W,., - Lffe can chuyin ddng d khoang dang

mang tai;

Wkt- Lffe can chuyen ddng d khoang ma d

dd tai chi cd d phan doan bang mang tai khdng

cd tram dan dong (tffc la kheang giffa hai tram

din ddng lien kl);

n- Sd tram din ddng tren nhanh cd tai.

u day gia thilt rang, khoang each giffa cac

bang trd Iffc dffdc chon sao cho Iffc can chuyin

ddng d cac doan giffa cac bang trd liic tac

ddng cua nhanh khdng tai bang Iffc can.

Chuyen ddng d cac dean giffa cac bang trd Iffc

tac ddng nhanh cd tai. De danh gia chilu dai

can thilt cua bang trd Iffc can phai dffa vao sff

dijng quan he:

K^ (5)

kc

Khi sff dung (3) va (5), ta cd:

KHCNM SO 11/2010* CO DifiN MO