Bo co TTKT Nhm 11

Phn I : Thy Lc

Bm bnh rng n khp ngoi

1, c im v thng s lm vic ca bm bnh rng :

1.1,c im : -Bm bnh rng l loi my roto c s dng rt rng ri v nhng u im nh: kt cu n gin, d ch to, tin cy cao, kch thc nh gn, s vng quay v cng sut trn mt n v trng lng ln, c kh nng chu qu ti trong mt thi gian ngn.. Bm bnh rng c s dng trong h thng truyn ng thy lc th tch c cng sut khng ln. Trong nhng h thng truyn ng th tch c p sut lm vic cao, bm bnh rng thng c dng lm bm s cp.- Nhc im : +n khi lm vic vi s vng quay ln+q=const nn khng thc hin c vic iu chnh lu lng v p sut khi s vng quay c nh.

1.2,Thng s lm vic : +q = 0.2 200 cm3/vng+pmax = 250 300 bar+n = 500 6000 v/ph

2, Kt cu v nguyn l lm vic ca bm bnh rng n khp ngoi 2.1, Kt cu :

1,2-giong cao su ; 3-l ; 4-pht c trc ;5-np ;6-bc ;7-v bm ;8-BR ch ng ;9-BR b ng ;10-bu lng ;11-giong lm kn ;12,13-vng chn- c im kt cu: + Cc bnh rng ch ng v b ng n khp ngoi vi nhau v c t kht trong Stato 1. + Khoang ht S v khoang y P thng c lm dng khe hp, c th b tr khoang y nm lch v pha bnh rng ch ng mt lng no san u ti trng cho 2 bnh rng v bnh rng b ng chu ti ln hn bnh rng ch ng. + Nu bm khng lm vic o chiu th khoang ht c lm ln hn khoang y. + Thng thng gim s thay i t ngt ca p sut cht lng vng n khp ngi ta c th lm cc rnh thot thng vng n khp vi khoang ht hoc khoang y, rnh thot ny c th l l thot hng knh hoc rnh nm b mt tip xc gia mt u ca bnh rng v Stato

2.2, Nguyn l lm vic : a.Bnh rng ch ng c ni vi trc ca bm quay v ko theo bnh rng b ng quay. Cht lng trong cc rnh rng theo chiu quay ca cc bnh rng vn chuyn t khoang ht n khoang y vng theo v bm. Khoang ht v khoang y c ngn cch vi nhau bi nhng mt tip xc ca cc bnh rng n khp v c xem l kn. Khi mt cp bnh rng vo khp khoang y, cht lng c a vo khoang y b chn p v dn vo ng ng y. l qu trnh y. ng thi vi qu trnh y, ti khoang ht c mt cp bnh rng ra khp, dung tch ca khoang ht c dn ra, p sut khoang ht gim v cht lng s c ht vo bung ht t b cha thng qua ng ht vo bm. Nu p sut trn mt thong l p sut kh quyn th p sut khoang ht s l p sut chn khng V nguyn l, nu bm ln tuyt i, ngha l gia khoang ht v khoang y khng c s r r cht lng qua nhau hoc r r cht lng ra ngoi, th p sut ca bm ch ph thuc vo ti.Trong thc t, bm khng th no hon ton kn do kh nng cng ngh ch to c cc khe h gia bnh rng v v bm nn c s r r cht lng t ca y v ca ht.- trnh hin tng qu ti cho bm, ngi ta b tr van an ton trn ng ng y.- Khi mun tng lu lng cho bm, th ta dng bm bnh rng nhiu khoang. Khi ch mun tng p sut th ta dng bm bnh rng nhiu cp.Ch : -Vng ra khp: Khoang ht-Vng vo khp: Khoang yb. Lu lng trung bnh ca bmQ = 2.0 .D.m.b.n0- hiu sut lu lng bm (0,8 0.9)D- ng knh BRm- modul BRb- chiu rng BRn- s vng quay ca bmn=const ; Q = const

c. K hiu

3, Cht Lng lm vic ca bm ph thuc vo - kn kht n khp 2 BR-Khe h nh rng v v bm-Khe h mt u (mt cnh BR v bc)Ch : +S ra khp v vo khp ca cc cp BR gy ra nhng thay i t ngt v p sut (gim,tng) s gy nn hiu ng khng tt v kh nng chu lc v xm thc c th xy ra ti khu vc ny.+ gim s thay i t ngt v p : lm cc rnh thot thng vng n khp vi khoang ht hoc khoang y. Rnh thot ny c th l l thot hng knh hoc c th l rnh nm b mt tip xc gia mt u ca BR v stato Bin php ny gy nn tn tht lu lng, gim hiu sut ca bm. Hoc c th dng BR nghing, BR ch V s vo khp v ra khp l t t.

+Qu trnh quay ca BR s to ra lc y hng knh ln cc trc v bc gim lc y hng knh to khe h gia nh rng v v bm ti khoang ht(lm thng cht lng rnh rng vi khoang ht). Phn lm kn c thc hin trn 1 cung hp hn khoang y

4, Nguyn nhn gy s mn v hng ca bm 4.1 , Mi mn do du bn Du bn l nguyn nhn thng gp nht gy ra h hng bm bnh rng m biu hin ca n l khi cng sut v tc lm vic ca h thng thy lc b yu i & chm li. Du bn gy ra h hng ton b cc chi tit ca bm bnh rng, c bit l bc s 8, bung bm, cc bi-bc, b mt rng v c trc. Cc ht bn c th sn trong thng du hoc i vo trong h thng khi lm vic nh qua pht u trc (b mn/hng) khi bm hot ng mi trng bi bn

Mi mn rng do du bn

Mi mn c trc

4.2,Mi mn do cc ht kim loi: Cc ht kim loi c trong du thng l do t cc chi tit b h hng v c trong h thng m khng sc ra ht. H hng do ht kim loi gy ra thng lm cho bm nhanh chng b h hng ty thuc vo s lng v kch c ht kim loi c sn trong h thng thy lc. H hng do nguyn nhn ny thng c nhn bit bi rt nhiu cc vt cy xc su xoy trn trn b mt ca bc s 8. Nu bm hot ng nhiu hoc khng pht hin h hng dng li ngay th b mt bc s 8 s b cy xc hon ton, rp v sc.i vi bc c trc & b mt lm vic ca trc: Thng s c nhiu vt xc trn b mt lm vic, ph thuc vo: - Mc nhim bn ca h thng thy lc. - p sut lm vic. - Ti trng lm vic trn trc bm, thng thy nh hng nht i vi bm nhiu tng, khi s c tng b h hng nhiu hn do ti trng trn trc ca cc tng khc nhau, ph thuc vo chiu dy rng. i vi b mt cnh cp bnh rng n khp (cn gi l mt u): S b cy xc thnh cc vnh nhp nh, khng phng do cc ht bn kim loi mi mn (c sn trong h thng v gy ra do a bc s 8 b mi mn trc

Mi mn bc s 8 do cc ht kim loi

4.3,Hng do lp rp: G rp bm vo h thng khng ng c th gy ra rt nhiu dng h hng khc nhau. Trng hp hay gp nht l trc bm lp qu st vi trc ng c hoc/v khp ni. Lc trc bm s chu mt ti trng ln hn, nh hng trc tip ln bc v nht l bc s 8 (pha ui) gy hng. Lp rp li khng ng cch cc chi tit ca bm sau khi tho kim tra cng l nguyn nhn chnh gy ra h hng. Cc chi tit hay b lp sai l:- Lp ngc bc s 8 hoc bung bm (ca ht/y).- Cc giong pht v vnh lm kn khng ng.- Lc sit bu lng khng u.

Lp rp sai gia bc s 8 v v bm

4.4, Xm thc gy ph hy b mt lm vic ca bung bm (ca ht), cp bnh rng v bc (pha rnh du bi trn). Du bi trn cn thit duy tr mt p sut thy ng gia bc trc v c trc. Khi lp mng du ny khng c duy tr trc bm s pht nhit v gy ra chy hng. Hin tng mt du bi trn thng xy ra khi: - Thiu du cp hoc bm b quay ngc chiu trong mt khong thi gian. - Khng kh c ln bn trong ng du ht ca bm. Thng thng bc trc bm s b h hng trc sau s ph hy bung bm (pha ca ht) do cp bnh rng b p xung c vo b mt v bc s 8

Hng trc do thiu du bi trn

Hng b mt bung bm

4.5, H hng do qu nhit-Bm hot ng qu nhit gy ra cc vt en trn b mt cnh cp bnh rng v bc s 8 ng thi lm chy hoc bin cng cc vng zong lm knBc s 8 hng do qu nhit , vng zong s 3 b bin dng

4.6, H hng do p sut qu cao:Thng thng c hai nguyn nhn gy ra hin tng qu p:- Khng c valve p sut hoc n khng m khi n gi tr cn bo v hoc- Valve p sut t qu caoCc h hng thng gp s l:- Trc bm hoc cc bnh rng b gy, m.- V bm b nt/v.

5, nh hng cua s ket cht long chn rng cua may bm trong qua trinh lam vic

-Mt hin tng xy ra trong bm bnh rng la s ket du chn rng khi hai rng n khp nhau (luc nay du trong o bi ong kin). Khi bi ket du, se gy ra tai trong ln tac ng ln banh rng, gy nong du anh hng ln n b mt cua rng. Khi du bi nong, cht long bc hi se gy xm thc trong may bm.-Cch khc phc : +Gia cng trn hai bac lot truc rng phia di cua bm hai ranh thoat+ Ranh thoat trn thanh vo bm;+Ranh thoat hng kinh chn rng va trn truc quay+Khoan cac l khoan hng kinh chn rng. Cac l nay thng vi cac ranh thoat trn truc quay, dn cht long n ca hut hay ca y

6, Tn tht va hiu sut trong bm banh rng-Tn tht c khi la tn tht do ma sat gia cac b mt chi tit co th chuyn ng tng i nhau. Hiu sut c khi cua bm banh rng khoang t 0,8 n 0,95 phu thuc vao kt cu va cht lng ch tao bm. -Tn tht lu lng trong bm banh rng gm:+Tn tht ro ri gia mt u cua banh rng va thanh trong cua stato tn tht nay phu thuc vao chinh xac gia cng cua hai cum chi tit rto va stato ( b mt tip xuc). Tn tht nay rt quan trong chim khoang 75% n 80% tn tht lu lng toan b. +Tn tht do dong cht long chay ngc qua khe h vong gia inh rng va mt trong cua vo bm. +Tn tht lu lng do tao ranh c y giam lc hng kich hoc han ch s thay i ap sut t ngt vung n khp. Lu lng hao hut nay c tinh tuy theo kt cu cua ranh. +Tn tht lu lng do cac ranh khng in y cht long, hin tng nay thng gy nen dao ng phu cua ap sut vi gn n khu vc khoang y cht long co xu hng chay ngc vao cac ranh. han ch hin tng nay co th dung cac bin phap sau: -Tng ap sut mt thoang hoc t bm thp hn b hut tao c ap sut khoang hut nho hn ap sut li tm cua banh rng.-Giam vn tc hut cua cht long nho hn 2- 3 m/s.-Han ch vn tc lam vic cua banh rng vn tc cua inh rng nho hn 6- 8 m/s.Thc t cho thy hiu sut lu lng chung cua banh rng t 0,7 0,9

7, Dung sai lp ghp, vt liu ch to v yu cu k thut khi gia cng cc chi tit7.1. Trc v - Bm bnh rng thng c 1 trc ch ng, 1 hay nhiu trc b ng, cc trc c th c lp gi 2 u hoc lp cng xn, c th l trc bc hoc khng bc ty theo tng kt cu c th - Vt liu ch to trc thng dng thp hp kim 20X, 12XHA, 13XHBA... c xementic ha i vi cc my quan trng khi yu cu lp trn trc cc con ln hnh tr. Vi nhng bm c ln thng thng, trc ca bnh rng thng c ch to bng thp 40X hoc thp 45 c nhit luyn b mt ( cng 54-56 HRC. Gia cng c kh m bo bng 5 - 8, o mt u: 3.03, van: 0.0057.2. Bnh rng- Vt liu gia cng bnh rng c th dng thp 45, 50 ti v ram t cng 52-58 HRC i vi cc bm bnh rng lm vic vi p sut thp v trung bnh (5m/s) vt liu gia cng bnh rng thng dng thp hp kim 20X, 40XH, 18XH13A...nhit luyn thm cacbon v thm nito t cng 58-64 HRC.- Khi gia cng bnh rng cn lu nhng yu cu k thut sau: + khng ng tm ca cc ng knh nh: 0.02 + o ca Profil rng vi mt u: 0.05 + khng song song ca cc mt u: 0.01 + khng vung gc ca cc mt u vi trc: 0.01 + cn v ovan ca cc bnh rng: 0.01 + bng ca cc b mt gia cng: 7 - 87.3. V bm - Stato- Trn khoang ht v khoang y thng c lm dng khe hp, c mt chiu l: b + (4-6)mm (b l chiu dy ca bnh rng tnh bng mm), chiu kia c xc nh theo gc 1 v 2. Theo kinh nghim, gc 1 nm trong khong 76-90 , gc 2 ca khoang y nm trong gii hn 45-86 .- Vt liu ch to v bm bnh rng c th bng gang c, ng c, nhm c, thp c hoc thp hp kim.- Khi gia cng c kh v bm cn m bo: + Dung sai cc tm l trc khng ln hn 0.01 + khng song song ca cc tm l trc 0.01 + khng vung gc ca mt u vi cc l trc 0.01 + B mt kch thc l tip xc vi nh rng khng cho php c li + bng ca cc b mt to khe hp lm kn 7- 8

Phn II : Kh Nn

My nn kh piston 2 cp , b tr hnh ch V

1.Tng quan v my nn kh.

1.1,u nhc im ca h thng truyn ng bng kh nn.* u im:Khng kh nn c tnh n hi, trong sut, khng c hi, kh bn la, khng b lng ng, v khng kh c v tn trong thin nhin.Kh nng qu ti ln ca ng c kh. tin cy kh cao, t trc trc k thut.Tui th ln.Tnh ng nht nng lng gia cc c cu chp hnh v cc phn t chc nng bo hiu , kim tra, iu khin nn lm vic trong mi trng d n, v m bo mi trng sch v sinh.Do trng lng ca cc phn t trong h thng iu khin bng kh nn nh, hn na kh nng gin n ca p sut kh ln, nn truyn ng c th t c vn tc rt cao.Do kh nng chu nn (n hi) ln ca khng kh cho nn c th trch cha kh nn mt cch thun li. Nh vy c kh nng ng dng thnh lp mt trm trch cha kh nn.C kh nng truyn ti nng lng i xa, bi v nht ng hc ca kh nn nh v tn tht p sut trn ng ng t.Chi ph thp thit lp mt h thng truyn ng bng kh nn, bi v phn ln trong cc x nghip cc h thng ng dn kh nn c sn.H thng phng nga qu p sut gii hn c m bo.* Nhc im:Thi gian p ng chm so vi in t.Kh nng lp trnh km v cng knh so vi in t, ch iu khin theo chng trnh c sn. Kh nng iu khin phc tp km.H thng truyn ng bng kh nn c lc truyn ti trng thp. Khi ti trng trong h thng thay i, th vn tc truyn cng thay i bi v kh nng n hi ca kh nn ln cho nn khng thc hin nhng chuyn ng thng hoc quay u.Dng kh nn thot ra ng dn ra gy nn ting n, lm nh hng dn sc khe con ngi.Hin nay trong lnh vc iu khin ngi ta thng kt hp h thng iu khin bng kh nn vi c hoc in, in t. 1.2,Phm vi ng dng ca my nn trong cng nghip.

My nn xut hin t lu, ngay t thi c c cc loi my thi kh dung trong sn xut ng v st, k c my thi kh chy bng sc nc. Ti th k 18 my nn piston xut hin v na u th k 19 cc loi qut ly tm, hng trc cng ra i cng vi s xut hin ca truyn ng hi nc v in.Nhng nm gn y cng nghip ch to my nn t c nhng thnh tu ln: sn xut ra nhng my nn piston c nng sut hng 10000 m3/h v p sut ti hng nghn at, nhng my nn ly tm v my nn trc vt c nng sut v p sut cao cng ra i.

Khuynh hng pht trin ca my nn l gim nh khi lng; tng hiu sut, tng vng chc khi lm vic, t ng ho vic iu chnh nng sut v m bo an ton.My nn hin i c s vng quay ln, ni trc tip vi ng c. Trc khuu ca my thng l roto ca ng c. My c trang b b phn iu chnh nng sut nhiu cp hoc v cp, ng thi c trang b cc b phn bo v, m bo dng my khi khng c du, khng c nc lm ngui v khi nhit nn qu cao.

1.3, Nguyn l hot ng chung v phn loi my nn.

Nhim v ca my nn l tng p sut cho mt cht kh no v cp lu lng cho qu trnh cng ngh khc; to ra s tun hon ca lu th trong chu trnh (my lnh) hoc duy tr p sut chn khng (c chn khng, sy thng hoa) cho thit b khc, trong trng hp ny my nn gi l bm chn khng.a. Nguyn tc hot ng.-Nguyn l thay i th tch (my nn kh kiu piston, bnh rng, cnh gt, trc vt): khng kh c dn vo bung cha, ti y b phn lm vic (piston trong xylanh hoc roto trong stato) s chuyn ng lm th tch bung lm vic gim i, nn khng kh trong bung cha, p sut bung cha s tng ln.

-Nguyn l ng nng (my nn cnh dn kiu: ly tm, hng trc): khng kh c dn vo bung cha, p sut c to ra bng mt ng nng ca bnh dn. Nguyn tc hot ng ny to ra lu lng v cng sut rt ln.b. Phn loi. Theo nguyn l lm vic: My nn th tch, My nn cnh dn

Hnh 2-3. My nn kh piston gii nhit bng gi

-Theo p sut : Hnh 2-4. My nn kh piston b tr kiu ch v oMy nn p sut thp p15 baroMy nn p sut cao p15 baroMy nn p sut rt cao p300 bar-Theo s cp: My nn mt cp v my nn nhiu cp-Theo loi kh: My nn khng kh v my nn cc loi kh khc

2, My nn kh piston FUSHENG FVA

2.1.Phm vi s dng ca my nn kh piston FUSHENG FVA.

My nn kh piston FVA l loi my nn kh hin i, do cng ty FUSHENG sn xut. My c s dng rng ri trong cc ngnh cng nghip cng nh trong sn xut,sa cha phc v i sng hng ngy, thng c s dng trong lp rp t ng v trong c nhng vic khng chuyn ng lin tc, c th c nh hoc di chuyn. Mc ch chnh ca my nn piston l cung cp kh nn cho cc thit b lm sch chi tit my, cc thit b my khng th lm sch bng tay v nc c, dng cung cp kh nn cho cc my t ng, dy chuyn t ng, my phun, my sn.My nn gm 2 piston, c b tr cch nhau 120 . L loi my c lm mt bng gi.

2.2.Nguyn l lm vic ca my nn kh piston FUSHENG

My nn kh c vn hnh bi mt ng c in. Khi ng c in lm vic, mmen quay ca ng c to ra s thng qua b truyn ng bng dy ai truyn mmen quay n trc khuu dn ng trc khuu ca my nn quay. Khi trc khuu quay th thanh truyn lin kt vi trc khuu s chuyn ng song phng, chuyn ng ny ca thanh truyn truyn ng cho piston thng qua u nh thanh truyn v cht piston dn ng piston chuyn ng tnh tin, kh hi v tun hon. My nn ny c hai piston. Khi my nn hot ng ngi vn hnh s iu chnh lu lng ca khng kh vo my nn, khng kh trc khi vo my nn c i qua b phn lc th lc bi bn.-Qu trnh ht ca my nnPiston t im cht trn bt u chuyn ng tnh tin xung di. p sut bn trong xylanh bt u h xung ti van ht bt u xut hin s chnh p gia trong v ngoi xylanh. Khi p lc ny ln hn lc n hi ca l xo van ht v lm cho van ht m, khng kh s i vo xylanh qua van ht thc hin qu trnh ht kh. Khi piston bt u i xung n im cht di th lc ny p lc ti van ht s khng ng k do s chnh p gia trong v ngoi xylanh rt nh, v p lc tc dng ln van ht nh hn lcn hi ca l xo, van ht ng li kt thc qu trnh ht kh (van ht l van mt chiu khi khng c lc ht th n lun c ng kn nh lc y ca l xo)-Qu trnh nn v y khPiston bt u chuyn ng tnh tin t im cht di i ln, kh trong xylanh bt u b nn li, p lc kh nn bt u tng ln. Khi p lc ny vt qu p lc kh khu vc van thot kh v lc p l xo van thot kh th van thot kh m ra, kh p trong xylanh s thot ra. Khi piston ln n im cht trn th vic thot kh s kt thc, van thot kh vi p lc l xo ln hn p lc kh nn bn trong xylanh s ng li. Kt thc qu trnh nn kh.

Kt cu bn trong u my nn piston 1-ng gii nhit; 2-Van ht; 3-Np xi lanh; 4-Piston; 5-Trc khuu; 6-Xecmng; 7-Tay bin; 8-Bc n ;9-Lc kh;10-B ngt t ng

2.3. Kt cu chi tit

2.3.1.Thn my

Thn my l gi cc b phn khc ca my, l s lin kt tng ng gia xi lanh v ng ni trung gian. Do vy thn my phi c n nh ln, nng v bn. Trong khng gian ca thn my b tr trc khuu chuyn ng quay trn v cha du bi trn. Hai thnh bn c cc ca c np y, kch thc ln c th tho, lp cc b phn bn trong. Trn mt vch c knh thm du v l du. Kt cu thn my c dng hnh hp kiu nm c cu thnh bi b mt thn my, np trc trc v sau, trc thn my c lp kt cu quay xe v b o v tr du, u dn du bi trn. Vt liu ch to thn my l gang xm, thn my c c sn.

2.3.2.Trc khuu.Trc khuu l b phn nhn chuyn ng quay trn t ng c, ri cung vi tay bin to ra chuyn ng tnh tin ca piston. Trc khuu chu chuyn ng un v xon. Trong my nn kh ny th trc khuu c s khuu l 3. Bn trong trc khuu c khoan to ng dn du bi trn cho thanh truyn, , hp m kn, trc khuu l ln. Trn m khuu c gn b phn cn bng ng, nhm m bo v nng cao cht lng tnh chuyn ng quay cn bng cho trc khuu.Cc yu cu k thut ca trc khuu :- o ca b mt ngng trc so vi ng tm trc tng ng khng qu 0,5 sai s cho php ghi trn bn v.- khng song song ca ng tm ngng trc lp bin vi ng trc chnh khng qu 0,02 (mm) trn 100 (mm) chiu di.- o ng tm ngng trc pha lp vi ng c khng vt qu 0,03 mm.- bng b mt cc ngng trc lp bin, phi t cp 9, cc ngng trc lp hp m, lp bnh rng, ro to ng c c bng b mt cp 7.-Cc phn khng lp rp ca trc ch cn ng kch thc v tin sch

2.3.3.Thanh truyn

2131453 3 1R21R8,574 2

Thanh truyn1- u nh thanh truyn ; 2- u to thanh truyn ; 3- Bulng u to thanh truynB phn thanh truyn kt ni trc khuu v piston. Thanh truyn c nhim v truyn chuyn ng quay t trc khuu thnh chuyn ng tnh tin ca piston, trong thn thanh truyn c l du thng sut, u to thanh truyn lin kt vi trc khuu, u nh lin kt vi piston thng qua cht piston. u to thanh truyn chia thnh hai na v ghp bng bu lng ai c kp, bn trong c lp bc hp kim babit, khi lp mi hay thay bc bin th dung cn thp l dy 0,25 mm m gia hai bch ca bin. Cc l cn gip ta chnh c khe h cn thit. Sau mt thi gian lm vic bc b mn th b bt cn i iu chnh.

2.3.4 . Piston

2.3.5. H thng bi trn H thng bi trn ca my nn kh piston l kiu bi trn t nhin. Du bi trn c cha trong cacte. Khi my lm vic, trc khuu quay, cc khuu v u to thanh truyn quay ngp trong du, du vung t ln bi trn piston v thnh xylanh, ng du trong trc khuu dng bi trn c khuu, v cc b phn ma st khc cc c cu truyn ng. Du bi trn c vo ng mc quy nh. Duy tr mc du lun nm mc gii hn trn v gii hn di ca knh thm du. My nn kh s dng nht SAE 20 vo ma ng, SAE 30 vo ma h. S dng nht hp l th tc ca my s t c nh mong mun, nm trong tc gii hn.

SVTH: Vng Trung c-Lp CKL1-MSSV: 20110238 Nguyn Vn Long-Page 19