Một giải pháp thiết kế chế tạo cảm biến đo lực lớn

d Id duflng kinh phdn t i bifin dang, kich thuflc cfl tdm quan ttgng quyfit dinh dfin dfl Ifln cia luc cdn Che dfl nhifit luyen vd dfl cing cia ttu bifin dang quyfit dinh dfin dfl chinh xac vdflndinh cia cam bifin Cfln cdc kich thuflc va chi tifit khdc chi cfi tinh chdt dfi lap rap tao ddng va chinh "0" cho cam bifin luc vat lieu ly luflng dfi chfi tao phdn ti bifin dang cho loai cam bifin Id thfip Phdp 35NCD6 vi dfi gia cflng vd nfiu nhiet luyen ding qui trinh se cfl dfl cing dfiu dfin 60 HRC cing vfli giai tuyfin tinh rflng Tuy nhien nfiu khflng bam bao ding yfiu cdu nhifit luyfin co thfi ddn dfin stt nttt rfi, clhig khfing dfiu vd vdy san phdm se mdt gia tri si dung Vfli thep Nga 40X, khfl gia cflng cdc giai doan ddu, song vdn dfi nhiet luyen khflng dfli hfli khdt khe nhu dtfi vfli thep Phdp Dttcmg nhifin dfi fln dinh ban chfi va dac bifit Id giai tuyfin tinh hep Nfi'u chi chdp nhan giai tuyfin ti'nh ngdn vfli dfli tttgng thu nghifim cfi luc bifin dflng khflng Ifln thi nfin chgn thep 40X, re vd dfi tim uen thi truflng Si dung mflt stf bifiu thictt'nhtodn vfi sttc bfin vdt lifiu cing vfli cdc chi tieu ky thuat cia tem difin trfl se xdc dinh dugc kich thuflc Od cia cam bifin Tuy nhifin vific tinh todn ly thuye't chi mang tinh chdt dinh huong vd phai cfl ddy di cdc chi tieu ky thudt cia tem dien ttfl se dugc ddn len phdn ti bifi'n dang Dfi cfi mflt phdn ttt bifin dang ldm vific fln dinh mfit ddi lfin, ngodi vific tinh toan ly thuyfi't cfln phai cfl nhttng bifin phdp chgn Igc bang thuc nghiem vfli kinh nghiem thuc tfi nhdt dinh III GlAl PHAP THUC NGHIEM DE THlfiT Kfi', CH^ TAG C A M BIEN DO LUC DAY DONG CO PHAN LUC CO LON 3.1 Giai phap ve to hgp phan t i bie'n dang Tren co sd nhttng cam bifin luc cfl tmng binh nhu da neu ttfin se chfi tao dugc nhttng cam bifin luc Ifln theo nguyfin tdc ghep song song nhifiu tru don dfing nhdt Giai 440 phdp cung da dugc iJng dung dl cbl tao nhilu cam biln da nang, nhilu tham sd hoac nhilu phdn tham sd cfing luc Dl ed duge cam biln luc cho mue dfch dinh Iugng luc ddy cua eac loai ddng co phan lue c9 Idn nhu da nfiu, cdn khai thde trifit dl nhfing uu dilm cua cam bifi'n luc cd phdn tfi biln dang hinh tru Bdng vific tdng ducmg kfnh ngoai D cua phdn tfi biln dang Ifin mdt gidi ban cho phep cd thi tao nfin cam biln Ific cd gidi ban tfi 100 din 300 kN Nhd dd se tinh giam duge phfic tap cua kit cdu eua ghep song song Tuy nhien D khdng the tdng mai dugc, vi phdn tu bii'n dgng chi thuc su on dinh lien ki't bin vdt liiu ddng nhdt vd cd dd cdng da dugc nhiet luyen ddng deu a mgi vi tri Trong diiu kifin ciia ta, thep 40X hoac thep 35NCD16 eung chi la nhung loai thep cdng nghifip binh thudng, khfing phai Id thep dac bifit dugc luyfin rifing cho muc dfch sfi dung dac bifit Vdi chd't lugng cd ban va vdi diiu kifin cdng nghfi hifin nude, nhihig ddi hdi trfin khdng thi ddpfingduge Nhu vdy, dl ed dugc nhihig cam bien luc Idn, cdn phai thuc hifin giai phap ghep nhilu td hgp tru ddn hdi- tem biin dgng ddng nhdt lai dl tao nfin mfit cam biln luc Idn gdp nhieu Idn, theo nguyfin ly tdng hgp luc song song (hlnh 3) Dua theo nguyfin ly khdng nhi&ig ehl tao dugc cam bifi'n lue Idn ma cdn cd kha ndng md rfing nghifin cfixi cbl tao ede loai cam biln luc, mfi men ddc biet cho nhfingfingdung da dang Hlnh 3: Tl hgp phan tfi bien dang vd kit cau mach cdu cua cam bien luc diy ddng co phan luc co Idn Dl dam bao cam bifi'n lam vifie 6n dinh ngoai nhfing ylu td da nfiu trfin thi nhdt thilt ede tru bifi'n dang, vf du dang xet Id ba tru, eua earn biln phai ddng nhat Tfic la ba tru bien dang phai dfigc chi tao tfi cfing mfit loai vdt lifiu, ed kieh thude nhu vd dugc nhifit luyfin d cung mdt ehl dd dl dat dugc cung mdt dd cfing Ngoai vific gia cdng eg phdi dugc thue hifin rd't chinh xac cho cde khdp ndi eua phdn tfi biln dang vdi dl trfin va dl dfidi eua cam biln phai cd dung sai nhd nhat Cdc tru bifi'n dang dugc gdn vdi dl trfin va dl dudi bdi sdu bu ldng ddng nhdt Cac bu ldng vfia ed nhifim vu gha lap tao dang cho cam bifi'n vfia cd tdc dung chinh "0" cho cam biln, diiu dugc thuc hifin d budc hifiu chinh cam biln trude kilm chudn dl dua vao sfi dung 3.2 Thiet lap mach cdu cam biln va chgn vi tn dan tem Vdi cdc cam biln nhd fing dung nguyfin ly tem bifi'n dang thi mach cdu cua cam biln cd thi cd mdt, hai hoac ca bd'n nhdnh deu ehfia tem Trudng hgp tuong dd'i phd biln la bdn nhdnh cdu diu ehfia tem Thuc tl, mach edu cam biln tem difin trd biln dang la mdt cdu thudn trd Wheatstone C) dd, gia tri gde cua cdc difin trd tem diu nhu nhau: Rl = R2 = R3 = R„ Nlu nhu diiu kifin cdn bdng cdu duge thod man thi difin dp bdng "0" Vdi nhfing cam bien tu ehl tao, du sfi dung mdt tem hoac nhilu tem, dieu cfi't ylu Id phai bd tri tem tren cac nhanh edu cho difin dp dat duge tri cue dai Nlu bd tri khdng hgp ly, se cd thi xdy trudng hgp: Idn cua dien dp se khdng ddng kikhi dgi lugng vdo la cue dgi Cdu Wheatstone vdi bdn nhanh la bdn tem biln dang ed tri sd difin trd gde nhu se cd dd nhay Idn nhat va chi chieu biln dang trfin hai nhanh ddi xfing ngugc vdi chilu biln dang trfin hai nhanh ddi xdng edn lai Difin dp cua mach cdu ludn ty Ifi vdi difin dp ngudn nudi va vi vdyfingvdi mdt bifi'n ddi du nhd eua difin trd tem thi difin ap bifi'n ddi ty Ifi vdi: - Hiiu dgi sdcua cdc bii'n doi dien trd trin cdc nhdnh cdu ki - Tdng dgi sdcua cdc bien ddi diin trd trin cdc nhdnh cdu ddi ~ Neu trin mdi nhdnh cdu dugc mdc ndi tiip nhiiu tem thi gid Iri trung binh tucmg dng cua cdc bii'n dgng sedugc phdn dnh ddy du d ldi Ngay tfi tfnh toan ket cdu vd kfch thude phdn tfi biln dang thi da phai d'n dinh cae vi tri ddn tem difin trd, loai tem difin trd se sfi dung cung nhu cdu tnic tach ghep song song cfia mach cdu cam biln Cdu true maeh edu eua earn bifi'n ba tru dugc thilt ldp tfi 12 tem difin trd cd dac tfnh ky thudt gidng hfit nhau, dd tem ddng vai trd la tem vd tem ddng vai trd Id tem bfi trfi nhiet Vi tri dan tem trfin phdn tfi bien dang duge chgn eho tem phdi nhay nhdt ddi vdi cdefingsudt tdc dung Ifin phdn tfi biln dang va tem bu trfi nhiet ngoai tde dung tu bii trfi nhiet phai tro vdi cac fing sudt tdc ddng lfin cam biln Tfi dd tem dfigc dan dgc va ddi xfing trfin ba phdn tfi bifi'n dang, tem bu dugc ddn ngang trfin cde phdn tfi biln dang hinh I Trdi Rl3 Phai Ri; Rl4 Trong Ngoai a) Vi tri cac tem va bi ttfin ttu bien dang stf b) Mach cdu cam bifin luc ddy dfing co phan luc cfl Ifln Hinh 4: Vi tri ddn tem tren phan t i bien dang va mach edu cam hien luc ddy dgng co plian luc cfl Ifin 3.2 Dan va han ndi mach cam bien Ddy la khdu khd khan nhdt qui tnnh cbl tao cam biln Khau eung dugc chia lam hai qui trinh la dan va ddu day tao mach earn bien Nhu chung ta da bilt, cdng nghfi dan gifi mdt vai trd rdt quan trgng, chdt lugng ddn khdng bdo dam se gay nfin nhiing sai sd Idn din mfic khdng thi kiem sodt ndi, nhfing nguyfin nhdn ddng tile nhu trugt (thudng ggi Id bd), nhung tdc dfing cua dm udt ddn den dd cdch difin qud "ngheo nan" (thudng chi dudi vai chuc MQ) gifia dl tem va phdn tfi biln dang Di loai trfi tac ddng eua dm udt, tdt hon he't la thuc bifin cdc qui trinh dan mfii trudng khd rao, each ly hoan todn vdi mdi trudng dm udt, vi du nhu budng diiu hoa, ed thifi't bi hut dm Tem, keo phai dugc thudng xuyfin bao quan cdc binh cd silicagel Ngoai ra, vific xde dinh chfnh xdc vj tri gdn tem cung la mdt vdn de rdt quan trgng dl cd thi khfing nhfing ngan chdn nhfing sai sd ddn ma cdn cd thi dam bao dfige dd nhay tdi da eua cdc tem Theo kinh nghifim, dl xde dinh ehinh xac vi tri vd hudng cdn phai sfi dung loai tem chdt Iugng thdp, gid re (vi du nhu tem gidy, tem tu tao) kit hgp keo dan dl rfia nhu hd dan hoac son khdng mau di tham dd trudc (thf nghifim so bd) vi tri va hudng biln dang eua tem San phdm duge tao thudng gap phai mdt trd luc khd khdc phuc dd la giai phap lam giam tde dung cua qua trinh khulch tan Ddy la mdt hifin tugng x^y thudng xuyfin thdi gian dai, cae phdn tfi se di tru tfi keo ddn sang dl tem hoac sang phdn tfi biln dang lam thay ddi dd edeh difin, thdm chf cd thi ldm dfit doan ldp keo dan Giai phap bao quan ban chi din mfic thdp nhdt tac dOng cua hifin tugng khufi'ch tdn ddi vdi cam biln la sdy khd va bdo quan binh ehfia silicagel Nhd do, cam biln cd the dugc sfi dung lifin tuc nhilu nam md vdn gifi dugc tfnh 6n dinh vd dd nhay cua nd Trong qud trinh nghifin cfiu cbl tao cam biln nhd fitig dung nguyfin ly tem biln dang, mfit dilm khfing kem phdn quan trgng lufin dang duge ghi nhd dd la da dan sai tem lfin phdn tfi bie'n dang thi se khdng cdn v ^ dl gi dl ban nfia, khdng edn Id vdn dl chinh xdc eua hfi thdng hoac cung khdng phai la Idi chgn sai tem do, cang khfing phai Idi thilt ldp cdu khdng dung Vi ay he thdng da di Ifich hudng hodc trd nen vfi dung Tdm lai, dan lufin la mdt vdn dl ndi cdm thudc vl trinh dfi va kinh nghifim ngudi thue hifin Cung ehinh vi vdy, mgi vdn dl lifin quan din din ehdt lugng cam biln sfi dung tem biln dang chu ylu nam d edng doan ddn Nhu vdy, nhd fing dung phuong phap ghep nhilu td hgp tru ddn hdi- tem biin dgng ddng nhdt lai da tao dugc mdt cam biln luc ddy ddng co phan luc ed Idn trfin co sd nhiing phdn tfi bifi'n dang kiiu tru dac eae cam bifi'n Ific loai nhd Cam biln sau chi tao dugc hifiu chinh dn dinh da dugc Trung tdm Do ludng cap gid'y chfing chi hifiu chudn vdi sai sd eho phep nhd hon 1,5% va dai tdi 1000 KN IV K^T LUAN Do ludng cdc tham sd dfing hge ddng eo phan lue ed Idn Id mdt yfiu cdu cdp bdch nghifin cfiu thfi nghifim vd che tao cdc thiet bi bay cho cac yfiu edu chien luge cua mgi qudc gia Vdi dac difi'm ia lufin phai lam vific mdi trudng chay nd, xac sudt xay hong hoe vd thdm ehi phd huy cam biln la rdt Idn Vi vdy vific tu nghifin cfiu, ehl tao cdc cdm bifi'n cho eac ddi tfigng la rdt edn thilt tilt kifim dugc nhilu kinh phi Qua tnnh nghifin cfiu, ehl tao cam biln Ific ddy dfing co phan Ific c5 Idn ddng bd vdi he thdng cac tham sd ddng luc (phdn cung va mim) tu ehl tao se giai quyfi't hai hod cdc giai phdp khoa hgc va kinh tl nhdm tao san phdm cd gid re vdi quy trinh ehl tao kha thi, phu hgp vdi diiu kifin thuc tl eua ddt nude 443 Tdi lieu tham khdo: [IJ Ddo Mdng Ldm - Hodn thiin cdng nghi che tgo he thd'ng dp, life ddng ca ddng caphdn luc, de tdi cdp Bd Qud'c phdng, ndm 2004 [2] Ddo Mdng Ldm - Nghiin cdu thii't lap hi thd'ng dp sudt ddng ca ddng ca phdn lire, de tdl cdp Bd Qud'c phdng, ndm 2000 [3] Phan Bd, Ddo Mdng Ldm - Do ludng-sen xa, NXB Qudn ddi Nhdn ddn 2001 [4] Luu Quang Huy - Cdng nghi vdl lieu ca bdn ngdnh ca khi, NXB Dgi hgc Qudc gia Hd Ndi, 1998 ]5] John P.Bentley- Principle of Measurement System Longman scienlilic & Technical, England, 1995 [6] Willam M.Murray, Willam R.Miller - The bonded Electrical Resistance Strain Gale, New York, Oxford Universty Press, Inc, 1992 [7] Nathan P, Timothy R Initial flight tests NASA, California, July 2002

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