NGHIEN c t f u - T R A O B O I
DONG LUC HOC BOM LINH HOAT THEO TAI SKT DUNG TRONG HE THONG THUY LU'C
LOADING SENSING PUMP USED IN HYDRAULIC SYSTEM
PGS,TS. Tran Quang Hung, ThS. Pham Duy Hai, ThS. Lini Minh Hung Hgc vien Ky thuat Quan su
TOM TAT
l/u diem quan trong nhdt ctia hi thong thuy luc (HTTLj sit dting bam LS (Load sensing) let do chenh dp cua Id tiet liru van dliu khien co khd ndng khong che a xdp xl 1 MPa ke cd khi tdi thay doi. Gid tri cua chenh dp cud 16 tiet liru phii hap se ldm gidm hien tuang ndng lugng thOy luc bien chuyen hda thdnh nhiet ndng vd ton thdt lint luang do ro ri. Trong bdi viit ndy, chung toi se trinh bdy kit qud nghien ciru vd mo phong HTTL sir dung bam LS.
TCr khoa: Bam LS, he thdng thuy luc, mo phong.
ABSTRACT
The most important strength of hydraulic system using loading sensing pump Is the pressure differential of the throttle orifice which can be controlled at approximately 1 MPa even when load changes. Suitable pressure differential of the orifice can reduce the transform of hydraulic energy Into heat and the flow loss leaked out of the surface of hydraulic elements. In this research, we present the research findings and emulate hydraulic system using load sensing pump.
Keywords: Load sensing pump, hydraulic system, simulation.
ISSN 0866 • 7056
TAP CHi CO KHf VIET NAIM, 86 5 nam 2015 BTvw.cokhlvietnam.vn
NGHIEN Cdu-TRAO OOl
l.DATVANDE
Trong qua trinh lam viec thuc ti ciia HTTL thi tai trpng thudng xuyen thay ddi. Dp chenh ap ciia van dieu khiin thay ddi theo tai trpng. Dp chenh ap ldn se xay ra hien tupng nang lupng thuy lire chuydn hda thanh nhiet nang cang cao. Viec khdng chd gia tri ciia dp chenh ap nay trong mpt pham vi nhit dinh cd kha nang nang cao hieu qua su dung nang lupng thiiy luc cua he thdng. HTTL sir dung bom LS cd kha nang dap iing dupc didu tren.
Trong qua trinh lam viec ciia HTTL, khi gia tri ciia tai trpng ngoai giam thi ap suit cua tai giam dan tdi dp chenh ap ciia van tang. Hoac nguac lai khi gia tri ciia tai tang thi ap suit cua tai tang dan ten dp chenh ap giam. Gdc ciia dia nghieng bom LS tir dieu chinh theo tin hieu phan hdi Clia tai de duy tri ap suat ciia bam phii hpp vdi ap suat tai trpng.
Cac thanh phan cua bam LS cd quan he vdi nhau bdi cac thdng sd ap suat, luu lupng va dp dich chuyen ciia cac chi tiet. Viec thiet lap cac phuong trinh ham truyen phan anh mdi quan he Clia cac thdng sd dd de lam ca sd cho viec md phdng HTTL.
2. DQNG LV'C HOC BOM LINH HOAT HTTL sir dung bom LS cd so dd nhu hinh (hinh 1).
Trong HTTL cd su dung bom LS, dudng dau cung cap cho tai cd sir dung tin hieu cung cap cho dudng phan hdi bang ap suat. Do dd, tai thay ddi thi tin hieu phan hdi cung thay ddi theo.
Ap suat d cudi dudng phan hdi, luc tac ddng ciia Id xo cung vdi ap suat bom dieu khien vi tri ciia con truat trong van tiiy dpng cua bd phan dieu khien bom dan tdi ap suat trong xy lanh ddn dieu khien dia nghieng thay ddi. Ap suat trong xy lanh
ddn tac ddng lam thay ddi gdc quay dia nghieng trong khoang gia tri tir 0^0,314 rad. Gdc quay dia nghieng se lam thay ddi thdng sd luu luong va ap suat.
Dia nghieng
Hinh I. Sa dd cua HTTL su dmg bam LS Theo [1], phuang trinh dich chuyen cua con trupt van:
Trong dd: x^^ - Chuyen vi ciia con truat, m; m^^ - Khdi luong ciia con trupt, kg; A - Dien tich ma ap suat tac ddng len con trupt, m^; b^^
- He sd giam chan ciia Id xo con truat, Nms';
k^,- He sd dp ciing cua Id xo con trugt, Nm"'; F^^
- Luc nen Id xo gay ra, N; P j^ - Ap suat ciia tin hieu cudi dudng phan hdi. Pa.
Thuc hien phep bien ddi Laplace phuong tnnh (1) thu dupc ham truyen cho con truat didu khien:
GM ^c,
i + i (2)Trong dd: co^^ - Tan sd dao ddng rieng cua con trupt cua bd diiu khiin, rad.s"'; C,^^ - He sd tat
dan bd dieu khidn; ^
iSSN 0866 - 7056
TAP CHi CO KHi VIET NAM, S6 5 nam 2015
NGHIEN Ctfu -TRA0D6I
K - ^
Vgi; ffi).
dao dong dia nghieng;
ll- 2^'"cK Cung theo [l]c6:
R.
(3)
(4)
(5)
(6)
df J A " dt -k^9„.
+ T^+k,P,-k,0,^P,-R,A,P, (7)
Gjs)> e.
*«*P.W-t,MP,W s- 24^ (8) Trong dd: co^
ciia dia nghieng, rads''
Tan sd dao ddng rieng
^ - He sd tat dan cua
^Ai
^dnb ~
'^drd
bs.
2-^k^ + kJ'^
kj - «j^a,o
•/*
R,^,
(9)
(10)
(11)
(12)
Phuong trinh thS hien m6i quan he giiia ap suit va luu lugng trong khoang cua xy lanh don dieu khien:
Trong do: R, - Chieu dai canh tay don cua pit tong, ra; x^ - Chuyen vi cua pit totig don, m; X. - Gia tri cue dai cua x m. J - Tong mo men qui dan ve true dia nghieng, Nms , b^^ - he so giam chin ciia he dia nghieng va pit tdng ddn, Nms; k ^ - H? sd dp cimg phu thudc vao gdc, Nm^ rad"'; k, - He sd md men xoan gay ra bdi ap suit, NmPa"'; k, - He sd md men xoan gay ra bdi ap suit, NmPa"'rad"'; T^^ - Md men quan tinh qui ve true dia nghieng, Nm.
Thuc hien phep bien ddi Laplace phuang trinh (7) thu duac ham truyen cho gdc quay dia nghieng:
* vA dt (13)
Trong do: V^ - ThS tich khoang xy lanh diSu khito, m'; Q^Qj - Luu lugng vao, luu lugng xa xy lanh don; x^, - Chuyen vi ciia pit tong don diSu khiSn, m; p - Mo dun diu thuy l?c, N . m l
Ltm Iugng cua bgm phu thugc vao got quay dia nghieng theo cong thuc [2]:
Trong do: D^ Th6 tich cong tac da bgm, m l r a d ' ; ra^ - Van t5c goc tr^c din dgngcto bom, r a d s ' ; Q^,, - Luu lugng ro ri cua bctm,m's';
N - S6 xy lanh'cua bom; R, - Canh tay don t ^ « mo men ciia bom, m; C^, - He s6 ro ri cua bora.
m ' s ' P a ; Pb - Ap suit ciia bgm. Pa.
ISSN 0866 - 7056
TAP CHi CO KHt VIET NAM, S6 5 nam 2015 www.cokhivietnam.vn
NGHIEN Ctfu-TRAODpi
Tuong tu bien doi Laplace phugng trinh khiSn tuy dgng, phu thugc vi tri dat ban d i u ciia (13) va (14) CO phuong trinh ham truy6n xy lanh cgn trugt va cac tac dgng cua con trugt la ap suit don va ap suiit bom: phan hoi cua tai P ^, ap suat bom P^ va luc nen 16
xo F , . .,(.)= 5 k L
{f:„.-x,)«»(,)*i:^^(s)4.*:„p,(i) (15)
oM- _n!d
•,iiM-K,,xJ,yK„p,(,)-g,(,)~ j_l, *'^'
Voi: ffij, =
Tir cac ham truyen d (2); (8); (15) va (16) md hinh hda bom theo so dd khdi hinh 2.
^•E]%-[
Hinh 2. Sa do khdi bom LS 3. M 6 PHONG HE THONG THUY LlTC BANG MATLAB SIMULINK
Viec md phdng HTTL cd sir dung bom LS, cho phep chi ra su phu thudc gia tri chenh ap Clia van dieu khien vao luc nen Id xo Fj^ tac dpng len con trupt cua bd dieu khien bam trong qua trinh lam viec. Vi tri con trupt duac dieu Trong do: co^ - Tan sd rieng cua xy lanh ddn, rad.s"';
(17)
(18)
(19)
Hinh 3. Sado mo phdng HTTL sir dung bam LS bdng Simullnk
Thong so cua bom [2]:
- Bp dieu khien: Khoi lugng con trugt m^=l,6.10-^ kg; Dien tich con trugt A^=3,2.I0-' m-; He so do ctmg k^=6,1.10*Nm'; He s6 giam chin b^ =2,21 N m s ' .
- Xy lanh don: Chieu dai canh tay don Rj^5,5.10"^m; Dien tich tac dgng len pit tong don Aj=3.36.10-<m2; ThS tich khoang xy lanh V^„=l,38.I0-'m'.
- Bom: So pit tong N=9cai; Chilu dai canh tay don bom pit tong R =5,5.10"^m; Dien tich pit tong bom A = 3,48.10"-^m; He s6 ro ri cua bom c^j=2.10""m's-'N'; Mo men quan tinh dia nghieng J^^=l,32.10'kgm'; He s6 d5 ciing phu thugcvaog6c:kj^=l,42.10'Nm-''rad"';Hes6m6 men xo5n do ap suit k|=2,83.10-'NmPa'; He so mo men xoan do ap suit kj=4,53.10'NmPa's;
He so giam chan cua he dTa nghieng b,^=5,5.I0"';
The tich khoang V|_=2.10-«ml " "^
ISSN 0866 - 7056
TAP CHI CO KHl VIET NAM. S6 5 nam 2015
NGHIEN cufu - TRAO D6\
Tai la xy lanh tay cin kiiu S130W vdi Cac gia tri luc nen Id xo F^ tac ddng len cac thdng sd [3]: Dudng kinh xy lanh IM),13m; con truat d do thi hinh 4 la 63N: 48N; 35N ung dudng kinh can d=0,09m; Hanh trinh s=0,149m; vdi dien tich bd mat chiu ap luc cua con trupt l i Khdi luang m^l46kg. A ^3,5.10"^ N.
Thdng sd diu thiiy luc: Md dun P^l,38.10^m"-; Khdi lupng rieng p ^ kgm^;
Dp nhdt myet ddi fi=1.74.10"hn-s"'.
Ket qua md phdng HTTL sir dung bam LS thu dupc dd thi dp chenh ap cua bom khi tai thay ddi (hmh 4).
De duy tri dp chenh ap giiia ap suit tai vi ap suat bom thi gia tri dat ban dau ciia id xo F khdng ldn hon gia tri 35 N.
4. K E T LUA>
Tir ket qua tren nit ra mdt sd kit luan sau:
i i ^:\l
1) HTTL sir dung bom cho phep khdng che dp chenh ap cua van duy tri miic xip xi 1 MPa.
° ^ ' ' ' ^ ^ „ ^ '' " ^ - 2) Ket qua md phdng cho thiy, d i duy tri dp chenh ap van d i i u khidn ciia HTTL thra Hinh 4: Dp thi do chenh dp giUa dp sudi bam vd dp yeu cau thi luc F,^ khdng ldn han 35N, ling vol
sudt tdi I- F.^, =63\:2- F, =48\. 3- F, =35.\ A =3.5.10-5N.*:'
Ngay nhan bai: 18/3/2015 Ngay phan bien: 23/4/2015 Tai lieu tham khao:
[1]. Trin Q " f 8 Hung Pham Duy Hai; Bang luc hoc vd md phdng van servo diiu khiin bam linh hoat theo lai. Tap chl Co khi \ iet Nam (2009).
^^'^•°"f'^,^''''^^°^\,''''*''"S'-'^I^VerimentalEval^^^^^
HiY/raWic i i a s i i , Ph.D Unu ersin of Saskatchewan [3]. Solar 130 W-V Sen ice Manual
[4]. Herbert E. Menitt (196"). //, diaulic Control System, John Wiley & Sons.
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