do án thủy lực 1343

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<p>H v tn :V Huy Thinh MSSV: 07138011</p> <p>LI NI U Trong qu trnh pht trin ca nn kinh t th trng cng vi s ho nhp vi nn kinh t khu vc v quc t, nghnh cng nghip nng chim mt v tr quan trng trong s pht trin ca x hi.T ng ho qu trnh sn xut ngy cng c s dng rng ri vo cc thnh phn kinh t. Bn cnh , cng vi nhng ng dng tin hc to cho qu trnh sn xut pht trin hon thin bng nhng my mc hin i c nng sut cao, cht lng tt v nng sut cao, cht lng tt v chnh xc cao. Trong cc thit b thu lc chim v tr quan trng v khng th thiu dc i vi mt my cng c bi n to ra chnh xc trong qu trnh chuyn ng cng nh thc hin cc chu trnh lm vic ca my theo yu cu mt cch nhanh gn, vn hnh n gin, hn ch c chi ph ch to bo dng v sa cha . So vi cc my p truyn dn bng c kh th my p thu lc c nhng u im ni bt : Kt cu my v cc b phn n gin To c lc p ln v c gi tr thay i tu theo yu cu gia cng D t ng ho trong qu trnh gia cng phng qu ti, s dng c cc chi tit tiu chun Vi s pht trin khng ngng ca khoa hc k thut, my p thu kh lc ngy cng c ci tin v hon thin nhm p ng c nhng yu cu v cng ngh phc tp. Gii thiu chung v h thng thu lc : T nm 1920, truyn ng thu lc c bt u c s dng trong cc my cng c. Lc u h thng thu lc ch yu dng thc hin chuyn ng thng v c cng sut b, v sau cn dng thc hin cc chuyn ng vong trn. Hn nay chuyn ng bng h thng thu lc c s dng rng ri trong hu ht cc nghnh k thut nh tn la, hnh khng, trong cc nghnh c kh nng nghip,</p> <p>giao thng vn ti ho cht my khai m ...T Trong nghnh c kh ch to my, chuyn ng bng thu lc c th ni c dng rng ri nht. c bit i vi my ct khim loi nh my t hp my iu khin theo chng trnh, ng dy t ng dng rng ri thu lc thc hin cc chuyn ng chy dao, chuyn ng chnh cng nh iu khin cc b phn my. Trong mt s my, th d nh my mi , my trut, hu nh ch dng du p thc hin truyn ng. Trong thi gian gn y du p c dng trong thit b thc hin chuyn ng ng b, trong cc h thng iu khin t ng. Trong qu trnh t ng ho my ct kim loi, cng nh t ng ho nghnh ch to my, truyn ng bng du p, cc c cu t ng bng du p cng c s dng nhiu hn na. 1 Nguyn l hot ng chung ca c cu thu lc : H thng thu lc l hn thng to ra cc chuyn ng nh cht lng, ch yu l du cng nghip. Chuyn ng c thc hin bng cch cung cp cho du mt nng lng di dng th nng ( bm du nn du ti mt p sut nht nh ) sau th nng ca du c bin thnh c nng ( p sut y piston chuyn ng) thc hin cc chuyn ng theo yu cu. H thng thu lc bao gi cng gm c hai phn chnh : c cu bin i nng lng ( bm du, ng c du ) v c cu iu khin chnh gm cc loi van. Ngoi ra cn c mt s thit b khc m bo s lm vic bnh thng ca h thng. C cu bin i nng lng : Bm du l phn du trong h thng thu lc bin c nng thnh th nng v ng nng. Bm du thng nhn truyn ng t cc ng c in v nn du n mt p sut nht nh. ng c du, xilanh truyn lc u c tc dng bin th nng ca du thnh c nng, ngha l bin p sut do bm du thnh cng c kh. - C cu iu khin : Ni lin gia bm du v ng c du hoc xilanh truyn lc l c cu iu khin v iu chnh m bo s lin tc trong qu trnh lm vic. Ngoi ra cn c mt s thit b ph khc nh ng dn, thit b lc du, thit b o lu lng.</p> <p> A : u im Truyn c cng sut cao v lc ln nh cc c cu tng i n gin hot ng vi tin cy cao i hi t phi chm sc bo dng. iu chnh c vn tc lm vic tinh v v cp, d thc hin t ng ho theo iu kin lm vic hay theo chng trnh cho sn. Kt cu gn nh, v tr ca cc phn t dn v b dn khng l thuc vi nhau, cc b phn ni thng l nhng ng ng d i ch. C kh nng gim khi lng v kch thc nh chn p sut thu lc cao - Nh qun tnh nh ca bm v ng c thu lc, nh tnh chu nn ca du nn c th s dng vn tc cao m khng s b va p mnh nh trong trng hp c kh hay in. - D bin i chuyn ng quay ca ng c thnh chuyn ng tnh tin ca c cu chp hnh . - D theo di v quan st bng p k, k c cc h phc tp, nhiu mch. - T ng ho n gin, k c cc thit b phc tp, bng cch dng cc phn t tiu chun ho. B : Nhc im Mt mt trong ng ng dn v r r bn trong cc phn t, l gim hiu sut v hn ch phm vi s dng. Kh gi c vn tc khng i khi ph ti thay i do tnh nn c ca cht lng v tnh n hi ca ng ng dn. Khi mi khi ng, nhit ca h thng cha n nh, vn tc lm vic thay i do nht ca cht lngthay i 3 -CHN LOI DU S DNG a : Yu cu i vi loi du s dng H thng du p lm vic trong gii hn vn tc, p sut v nhit kh ln. Trong iu kin lm vic nh th, du dng trong h thng du p phi tho mn hng</p> <p>lot cc yu cu mi c th m bo cho cc c cu lm vic c bnh thng. Da trn nhng kinh nghim thc t, cc yu cu i vi du c th tm tt nh sau : - C kh nng bi trn tt trong khong thay i ln ca nhit v p sut - nht t ph thuc vo nhit - C tnh trung ho ( tnh tr ) vi cc b mt, hn ch c kh nng xm nhp ca kh, nhng d dng tch kh ra. - Phi c nht thch hp ng vi iu kin chn kht v khe h ca cc chi tit di trt nhm m bo r du b nht, cng nh tn tht ma st t nht. - Du cn phi t si bt, t bc hi khi lm vic, t ho tan trong nc v khng kh, du dn nhit tt. - Trong nhng yu cu trn du khong vt c tha mn y nht. Hin nay c rt nhiu loi du ny c ch to vi nhng cht ph gia khc nhau nhm ci thin nhng c tnh nh : nht, bn ho hc v c hc. Trong khi s dng cht lng ca du c nh gi bng nht v bn. b : La chn loi du Trn thc t ngnh cng nghip du m sn xut c rt nhiu loi du khc nhau phc v cho nhng h thng du p c nhng yu cu khc nhau. Do khi thit k h thng du p, vic la chn loi du s dng ph thuc vo rt nhiu yu t v v th kh ra nguyn tc ng nht la chn, m ch da trn nhng nguyn tc tng qut. Nguyn tc chung la chn du l h thng lm vic vi p sut cao cn du c nht cao, v lm vic vi vn tc cao cn du c nht thp. T ta la chn loi du s dng l du k hiu ISO VG 150. 4 - B LC DU Khi lm vic du b nhim bn do cc cht bn t bn ngoi vo, hoc do cht bn trong bn thn du to nn. Nhng cht bn y s lm kt cc khe h, cc tit din chy c kch thc nh trong c cu du p gy nn nhng tr ngi v h hng trong hot ng ca h thng du p.Do trong cc h thng du p u dng nhng b lc du ngn nga cht bn thm nhp vo bn trong cc c cu . B lc thng t ng ht ca bm du. Trng hp cn du tinh khit hn t thm mt b na ca bm v mt ca ra ca h thng du p.</p> <p>Tu thuc vo kch thc ca cht bn c th lc c, b lc du c cc loi sau : - B lc th : c th lc nhng cht bn c kch thc n 0,1 (mm) - B lc trung bnh : c th lc nhng cht bn c kch thc n 0,01 (mm) - B lc tinh : c th lc nhng cht bn c kch thc n 0,005 (mm) - B lc c bit tinh : c th lc nhng cht bn c kch thc n 0.001 (mm). Trong may cng c thng s dng b lc trung bnh v b lc tinh, b lc c bit tinh c s dng trong phng th nghim. Da vo kt cu ta c th phn bit c cc loi b lc du nh sau : B lc li, b lc l, b lc giy, b lc n b lc nam chm..Ta i xt cc loi thng dng nht. a : B lc li - L b lc du n gin nht, cu to gm c mt khung cng v li bng ng bao quanh. Du t ngoi xuyn qua cc mt li v l vo ng ht. Hnh dng v kch thc ca b lc li rt khc nhau tu thuc vo v tr v cng dng ca b lc. - Do sc cn ca li nn du khi qua b lc b gim p sut, khi tnh ton tn tht p sut c th ly p = 0,3 0,5 (bar) - Li lm b lc dng loi c s l t 3100 17000 trn 1 cm2, vi li c s l 17000 trn 1 cm 2 c th lc c cht bn c kch thc trn 0,05 mm - Nhc im ca b lc li l cht bn d bm vo mt li kh ty ra .Do thng dng lc th, nh lp vo ng ht ca bm. Trng hp ny phi dng b lc tinh ng ra. b : B lc l - B lc l l b lc du dng nhng l thp mng lc du, y l loi c dng s dng rng ri nht trong h thng du p ca my cng c. - Kch thc cht bn c lc ph thuc chiu dy l thp, b dy ny thng l : 0,08; 0,12; 0,20; v 0,3 (mm). - S l thp cn thit s dng ph thuc vo lu lng cn lc, chng c gi tr ln nht l : 1000 1200 (l). Tn tht p sut ln nht p = 4 (bar), lu lng lc c th l 8 100 (lt/ pht)</p> <p>- B lc l ch yu c dng lc th, u im l khi tch cht bn khng cn dng my v tho b lc ra ngoi. c : B lc giy - nhng h thng du p i hi sch ca du cao, phi dng b lc bng giy hoc bng n, d. Nhng b lc ny c th lc c nhng cht bn c kch thc ln hn 0,005 (mm), c bit c th ch to nhng b lc c th lc cht bn c kch thc ln hn 0,002 (mm). - B lc giy c th ch to vi lu lng Q = 10 120 (lt/pht) vi p sut ln nht Pmax = 210 (bar). Nhc im ca n l chng bn v vic ty sch phc tp hn cc loi trn. d : Tnh ton b lc du - tnh ton b lc du, ngi ta dng cng thc tnh lu lng chy qua li lc. Q= Trong Q = 80 (l/ph) l lu lng qua b lc du. A ( cm2 ) din tch ton b b mt lc. p = p1 + p2 = 0,4 bar l hiu p ca b lc. = 27.10-2 [ poise ] nht ng lc ca du. [ l/ cm2ph ] h s lc, c trng cho lng du chy qua b lc trn n v din tch v thi gian [ l/ cm2ph ]. Gi tr c th tu thuc vo c im ca b lc vi b lc s dng l b lc li ta c = 0,05 [ l/ cm2ph ]. Ta chn b lc du trn c s din tch A c suy ra t cng thc trn. A= Thay s ta c 80 27.10 2 1080 cm 2 0,05 0,4 Q cm 2 A p (lt/ph). </p> <p>(</p> <p>)</p> <p>A=</p> <p>(</p> <p>)</p> <p> My p kim loi : (p Thp A.Phn c kh v tnh ton ca my p kim loi : 1. S lc cu to b phn lm vic :</p> <p>)</p> <p>2. Xi lanh p . 1. Xi lanh gi cht p 3.Bn 4. Sn phm .</p> <p>2.Nguyn l lm vic : Khi ta cp liu vo , 2 xi lanh (2) s gi cht vt t xi lanh (1) bt u cng vic inh hnh ca mnh , ty theo hnh dng khung (3) m ta s c sn phm(4) khc nhau. Kch thc phi : L = 50mm ; H= 2mm</p> <p> Phn tnh ton thit k :</p> <p>Ta tm lc q tc dng ln phi lm phi b un cong Chn h ta Oxy v xc nh lc tc dng nh hnh v Vi : EF=GH=IJ=15mm</p> <p>Momen qun tnh chnh trung tm :</p> <p>L h ) 50 2 = Ix = (3 3</p> <p>3</p> <p>12 12 3 I y = L h = 150 2 =20833,33( mm4 ) 12 12L3 h 1503 2 = 12 12</p> <p>=33.33( mm 4 )</p> <p>V biu </p> <p>M x , Qy</p> <p>:</p> <p>Ta c cc phng trnh :</p> <p>va + vb q EF q GH q IJ = 0</p> <p>m</p> <p>A</p> <p>= q GH (</p> <p>GH IJ EF + FG) + q IJ ( AB + BI + ) vB AB q EF ( AF + ) =0 2 2 2</p> <p>Thay s vo :</p> <p>va +vb = 45 q</p> <p>vb = 22,5 q</p> <p>va = 22,5 qvb = 22,5 q va , vb &gt; 0 nn chiu gi s ban u l ng.</p> <p> Hai lc</p> <p> Ta chia thanh lm 3 on : on 1-1 :</p> <p>( 0 z1 50 mm )</p> <p>Q1 = q ( z1 CE ) y z CE M 1 = q ( z1 CE ) 1 x 2 Vi :1 z1 = 0 ==&gt; Q1 = 17,5q, M x = q153,125 y1 z1 = 50 ==&gt; Q1 = 32,5q, M x = q528,125 y</p> <p>on 2-2:</p> <p>( 50 z2 100mm ) 2 Qy = q EF + v A q ( z 2 AG )EF 2 M = q 22 x</p> <p>+vA 2 z</p> <p> ( q 2 z ) AG 2 </p> <p>z AG 2 </p> <p>Vi :</p> <p>2 z2 = 50 ==&gt; Qy = 72,5q, M x2 = 939,375q2 2 z2 = 100 ==&gt; Q y = 122,5q, M x = 2014,375q</p> <p>on 3-3:</p> <p>3 Qy = q ( z3 JD )</p> <p>( 0 z3 50mm )</p> <p> z JD 3 M x = q ( z 3 JD ) 3 2 Vi :3 3 z3 = 0 ==&gt; Qy = 17,5q, M x = 153,125q3 3 z3 = 50 ==&gt; Qy = 32,5q, M x = 528,125q</p> <p>Ta chn thp c ng sut :</p> <p>[]v</p> <p>= 280 N mm</p> <p>2</p> <p>B- p: - Din tch bn p S = 4500 cm2 - Cng p max p = 24 MPa = 240 kg/cm2 - Lc p cn thit ln bn khun l Fg = S*p (tn) - Thc t th trng lng Ft cng gp phn to lc p ln bn nn Lc p thc t F = Fg Ft (tn). - T lc p ny (khong 836.8 tn) ta s chn p sut lm vic p tnh ra ng knh xy lanh p (bung trn) theo cng thc F/p = A vi A l din tch hnh trn ca xy lanh. - T A, tnh c ng knh D theo cng thc A = 3.14*D*D/4 - Lu bn l nu p sut p bn chn nh th ng knh D s to v ngc li. S c s cn nhc c th y v p nh th d chn bm, v cc b phn thy lc khc nh xy lanh to =&gt; Rt tn tin.. Ngc li nu chn p sut cao th bm li phi l loi cao p, cng tn tin. - qu trnh p ny hnh trnh p nh, gi s ch l 50 mm th ta c th tnh c lu lng Q (lpm) cn cp cho xy lanh. Q (lpm) = v * A - y v l vn tc lm vic ca xy lanh v c tnh v = S/t (S = 50 mm l hnh trnh p v t = 5 giy l thi gian p). - Vi gi tr p sut p (bar) v lu lng Q (lpm), bn s tnh c cng sut N (kW) cn thit cho bm hnh trnh p. N (kW) = p * Q / 612 C- Hnh trnh nhc khun: - Khi nhc khun th ch cn thng c trng lc Ft = 3.2 tn, thc t cn cng thm mt phn lc gy ra do nn lng du ln trong lng xy lanh p qua ng thot v thng. Lc ny Ff = 2-3 bar trn din tch A. Ff ~ 3 tn. Tng cng lc nhc khun = Ft + Ff = 6 tn. - Lc ny rt nh nn ngi ta thng dng mt (hoc 2) xy lanh nng ring. ng knh xy lanh ny (d) c tnh tng t nh xy lanh p. - Tng t xy lanh p, c th tnh c lu lng Q v cng sut N cp cho xy lanh nng. Nh vy l tnh c cc thng s tnh ton ca cc hnh trnh lm vic. Lc ny bn c th la chn cc thng s lm vic chun t catalogue/ti liu k thut cho h thng thy lc my p. C th s chn: - ng knh xy lanh p D &amp; xy lanh nng d. - p sut lm vic xy lanh p &amp; xy lanh nng. - Lu lng cp ca bm. 3.Tnh ton : 1 :H thng bn p A:Tnh ton h thng xilanh p</p> <p>a: Tnh lc p cn thit Ta chn sn phm : chiu di chiu rng chiu cao : 80 cm : 40 cm : 10 cm</p> <p>p lc ln nht Pmax = 15 kg/cm2 = 15.105 N/m2 Din tch tm g : Sg = a x b Sg = 80 x 40 =3200 cm2 Lc p ton b trn tm g P = Sg x Pmax P = 3200 x 15 =48000 N b: Tnh khi lng bn my Bn my lm t tn c khi lng ring Bn my gm 1 bn my p Khi lng 1 bn my p M V = V1 ..2 + V2 .25 V1 =20 x 2900 x1300 =75 400 000 mm3 =75,4 dm3 V2 = 20 x 120 x1300 = 3 120 000 mm3 =3,12 dm3 vy V =75,4 x2 +3,12 x25 =228,8 dm3 m =7,8 x 228,8 = 1784,64 kg Khi lng bn my l M = 4x1784,64 =7138,56 kg M chn 7,5 tn = 75000 N Lc cn thit nng bn my gm :khi lng 4 bn my +khi lng xilanh P-0 =85 000 N c: Tnh ton xilanh p chnh Hnh v xilanh tng lc m=v. = 7,8 kg/dm3</p> <p>- Chn cc thng s ca xilanh tng lc ng knh D = 180 mm ng knh d =300 mm ng knh cn dc = 150 mm Tit din lm vic ca piston c xc nh theo cng thc: F = F 1 + F2 Trong F1 = x R2 = ( =254,34 cm2 F2 = 1 3,14 ( d2 - dc) = ( 0,32 -0,152) =0,0529875 m2 4 4 D 2 0,18 2 ) =3,14 x( ) = 0,025434 m2 2 2</p> <p>=529,875 cm2 Din tch lm vic piston F =254,34 +529,875 =784,215 cm2 Trong h thng xilanh p ta s dng hai bm ,mt bm lng v mt bm p sut. Bm lu lng c nhim v cung cp du cho xilanh nng bn my,khi qu trnh p bt u th bm p sut hot ng e: Tnh lu lng cho bm lu lng</p> <p>Chn cc vn tc : Vp =0,5</p> <p>m m m ;Vmax =3 ;Vmin =0,2 ph ph ph</p> <p>Lu lng cn cung cp khi lm vic vi vn tc ln nht l : Q max =F x Vmax =784,215 x300 =235264,5 cm3/ph Q max = 235,2645 chn Qmax =240 l ph l ph</p> <p>Lu lng cn cung cp khi lm vic vi vn tc nh nht l: Qmin =F xVmin = 784,215 x 20 = 15684,3 cm3 /ph Qmin =15,684 l ph</p> <p>Lu lng cn thit khi p : Qp =F xVp =784,215 x50 =39210,75 cm3 /ph Qp =39,21075 Chn Qp =40 f: Tnh p sut P sut nng bn my c tnh t phng trnh cn bng P1 F2 + P 1 F1 = G P1 = 85000 G = =108,389 N/cm2 F + F 784,215 l ph l ph</p> <p>P1= 10,8389 bar Chn P1 =15 bar P sut cn thc hin qu trnh p c tnh t phng trnh cn bng sau: P2 x F2 + P2xF1 =G + P P2 = G+P 117187,5 + 85000 = F1 + F2 784,215 Chn P2 =165 bar</p> <p>P2 =1602,717 N/cm2 =160,27 bar</p> <p>2 Bm v ng c 2.1 Bm v ng c thu lc l hai thit b c chc nng khc nhau.Bm l phn t to ra nng lng,cn ng c thu lc l thit b tiu th nng lng ny.Tuy th kt cu v phng php tnh ton ca bm v ng c thu lc cng loi ging nhau. Bm du l mt c cu bin i nng lng, dng bin c nng thnh nng lng ca du (dng cht lng). Trong h thng du p thng ch dng bm th tch, tc l loi bm thc hin vic bin i nng lng bng cch thay i th tch cc bung lm vic (khi th tch cc bung lm vic tng, bm rt du, thc hin chu k ht v khi th tch ca bung gim, bm y du ra thc hin chu k nn ). Tu thuc vo lng du do bm y ra trong mt chu k lm vic, ta c th phn ra hai loi bm th tch: - Bm c lu lng c nh, gi l bm c nh. - Bm c lu lng c th iu chnh, gi tt l bm iu chnh.Nhng thng s c bn ca bm l lu lng v p sut. ng c thu lc l thit b dng bin nng lng ca dng cht lng thnh ng nng quay trn trc ng c. Qa trnh bin i nng lng l du c p sut c a vo bng cng tc ca ng c. Di tc dng ca p sut, cc phn t ca ng c quay. Nhng thng s c bn ca ng c thu lc l lu lng ca 1 vng quay v hiu p sut ca ng vo v ra ng ra. 2.2 Tnh cng sut Cng sut cn thit ca bm l: Nb = Q max Po 612</p> <p>Trong : Nb :l cng sut cn thit ca bm (kw) :l hiu sut ca cc c cu trc bm : =0,9 Qmax : l lng du cn thit bung tri ca xilanh ng vi tc lm nht Po :l p sut cn thit ca ra ca bm</p> <p>Bm lu lng :</p> <p>Qmax =240</p> <p>l ph</p> <p>Po :p sut du cn thit ca ra ca bm =15 bar Nb = Bm p sut : 240 15 = 6,5 (kw) 0,9 612 Qmax = Qp = 40 l ph</p> <p>Po : p sut du cn thit ca ra ca bm : Po = 165 bar Nb = 40 165 =11,98 (kw) 0,9 612</p> <p>3 : Tnh ton ng knh ng dn du 3.1 : Gii thiu ng ng dn du ni lin cc phn t iu khin vi cc c cu chp hnh,vi h thn...</p>

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