NGHIEN cufu-TRAO Ddi
NGHIEN CLTU DANH GlA HE THONG THiiT Bj THU' NGHIEM MON VlT ME - OAI OC Bl TRONG OlfeU KIEN MOI TRU'QNG
TCVN 7699-2-30.
STUDYING ON ASSESSING THE EQUIPMENT SYSTEM TO TEST WEAR OF BALL SCREW UNDER THE ENVIRONMENT OF TCVN 7699-2-30
TrSn Due Toan', Nguyin Thi Thu Ha^ Pham Van Hiing^
'Khoa Cong nghe Co khi, Trudng Dai hgc Dien lire
^Khoa Co khi - Vu khi, Trudng Cao ding Cdng nghiep Qudc phdng
^Vien Co khi, Trudng Dai bgc Bach Khoa Ha Ngi
TOM TAT
Trin ca s& nghien cim mpt so phuang phdp do dich chuyen co dp chinh xdc cao, bdi bdo trinh bdy qud trinh nghien cuu, phdn tich vd thiet ki hi thong mdy thi nghiem xdc dinh mdn dpc tryc vit me - dai 6c hi (VMDB) khi tdi vd so vong quay thay doi, trong dieu kien moi tru&ng TCVN 7699-2-30. Thiit bi do co he thong do cdc chuyen dpng tinh tien vd do quay cita VMDB v&i do chinh xdc hgp ly, ddp ung dugc cdc thong so cdn nghiin ciru. Kit qud ddnh gid cdc thong so do Id tdi, toe dp vd sai lech tinh tien cho thdy thiet bi hodn todn dap ung cdc yeu cdu cita thuc nghiim.
Tir khoa: Vit me — dai dc bi; Tuoi thp; Mon; Thiit bi; Moi tru&ng.
ABTRACT
Based on studying some methods to measure transposition with high accuracy, this paper presented duration of study, analysis and design system of experimental machine to identify axial-wear of ball screw while having change in load and rotation speed, under the environment of TCVN 7699- 2-30. The working environment ofineasurement equipment to measure rotation and translation movement of hall screw had proper accuracy and met the studied parameters We assessed load, speed and translation deviation. The results showed that the equipment totally met the need of the experiment.
Keywords: Ball screw; Life; Wear; Equiptment; Environment.
ISSN 0866 - 7056
TAP CHI CO KHi VTET NAM, Sd 1 +2 nam 2015 www.cokhivietnam.vn
Av
NGHIEN cufu-TRAODdi
l . D A T V A N D E
VMDB la cum chi ti^t truyen ddng quan trgng trong may cdng cu CNC va cac thiet bi CO dien tii yeu cau chuyen dgng tinh tien ehinh xac. Theo thdi gian Iam viec, mdn eua VMDB lam suy giam do chinh xac cac chuyen dpng tinh tien do nd dam nhipm. Viec nghien ciiu sai I?ch vi tri do mon ciia VMDB can phai cd thiet hi do dugc cac thdng so dich chuyen cua dai dc bi va cac goc quay cua true vit vdi do chinh xac phu hgp, dac biet, khi VMDB Iam viec trong cac loai mdi trudng khac nhau. Dua tren co sd phdng thi nghiem Tribology cua Vien Co khi, Trudng Dai hgc Bach Khoa Ha Ngi, tac gia da phan tich, thiet ke va che tao dugc he thdng thiit bi do dap ling dugc yeu cau do.
2. GIAI QUYET VAN DE 1.2.1. Sir ddnguySnly
So do nguyen ly he thdng thiet bj do mon BKM-VMDB2014 khi tai va tdc dp thay ddi dupe the hien tren binh 1, vdi dae diem la toan bp cum do dugc ga lap ben ngoai tu BK- NA2.
Nguyen ly van hanh chung eua thiet bi:
True vit me dugc dan dpng tu dpng co, quay vdi sd vdng quay n, tai dgc true tac ddng len vit me duoc tao ra bdi ap luc dau trong pittong- xilanh. Sau mpt thdi gian van banh nhat dinh
"t", true vit me va dai dc bi se mdn. Khi dd, chuyen dpng tinh tien cua dai dc duoc do bang LS " f " se khdng dung vdi lupng chuyen ddng tinh tien "t^" dugc do bang LS trudc do thdi gian "t". Hieu cua t'^ - t^ chinh la luong mdn dpc true tdng cdng eua VMDB (thira nhan lupng tang them cua sai lech dpc true la do mon gay ra.
Hinhl: Sadd nguyen ly tong the he thong thiet bj Tren hinh:
1) He thdng tgo tdi 2) Tii nhiet dm 3) Bd truyen dai rdng 4) Bp VldDB thi nghiem 5) He thong do chuyen vi
Hinh 2: Nguyen ly do quang [1]
2.2.2. Phieffngphdp vd thiit bi do - Cum do chuyin dpng VMDB Thidt bi thii nghiem mdn BKM- VMDB2014 dugc trang bi be thdng do thang va he thong do quay. Ca bai he thdng nay deu dung thudc do quang hpc, trong do thudc do thdng do chuyen dpng tinh tien cua dai 6c, thudc do quay do chuyen dpng quay cua true vit. Ca hai chuyen ddng nay deu la khu hdi.
Nguyin ly do bdng thu&c quang Khi 3 chuy8n ddng tinh tiSn, khe sang ciia 3 se dich chuyin tuong ddi vdi khe sang*^
NGHIEN cufu-TRAO Ddi
eua 4. Khi hai khe sang trimg nhau, 5 nhan dugc tin hieu xung, khi lech nhau bang chieu rpng khe, 5 khdng nhan dupe tin hieu xung.
Lugng dich chuyen cua 3 so vdi 4 dugc xac dinh bdng sd tin hieu xung thu dugc d 5 vdi do rgng khe sang. Nguyen ly nay cd the ap dung cho ca do thang (3 dang thanh thang) hoac do quay (3 dang dia chia).
Dua tren yeu cau cua thuc nghiem, cac thiet bi do da dupe lira chpn de do chuyen dgng cua VMDB gdm cd: Thudc quang do thdng Liner Scale "LS" cua hang SINPO, ma hipu "JOXE-0" do chinh xac 0,001 mm de do chuyen dgng tinh tien cua dai dc; Thudc quang do quay Rotary Encoder "RE" ma hieu S48-8- 5000VL (5000 xung/vdng) cua hang LS de do chuyen dpng quay cua true vit me.
Tren co sd nghien ciiu va phan tich cac loai thiet hi do, da dua ra dugc so do nguyen ly he thdng tao mdn va do sai lech cua chuyen ddng VMDB tren hinh 3.
Tdc do quay true vit me dupe xac dinh qua gdc quay dugc ciia true vit me (phan hoi ti-en RE) va thdi gian quay.
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m i a' 1 "
. 1 .
Hinh 4: Sa dd thdy luc he thong tgo tdi Su dung bg truyen banh dai rang de dan dpng tir dgng co tdi true vit me, true vit me co chuyen dgng quay khii hdi, thay cac cap banh dai rang de thay ddi tdc dp true vit me. Cum tao tai dpc triie su dung pittong - xylanh thuy luc.
So do nguyen ly be thdng thiiy luc dugc the hien tren hinh 4. Dieu chinh van tran VTI, VT2 de thay ddi tai.
- Tu nhiet dm BK-NA2
Hinh 3: Sa do bd tri hi thong do - Cum do tdi toe dp quay true vit me Cum do tai dpc true tac dung len VMDB dugc xac dinh qua ap suat ddu "p" va dudng kinh xilanh - pittong "SXL - SPT". Sii dung cam biin ap sudt "SIEMENTS SITRANTS P250" cd do chinh xac <1%.
Hinh 5: Bo tri thiet bi tu nhiet dm Tren hinh:
1) Tu nhiet dm; 2) Cdm bien nhiet dp, dp dm;
3) Quat ddi luu khdng khi; 4) Thiet bf tgo dm;
5) He thong lam Ignh; 6) Den sgi ddt (gia nhiet).
ISSN 0866 - 7056
TAP CHi CO KHi VIET NAM, Sd 1+2 nam 2015 www.cokhivietnam.vn
NGHIEN cufu-TRAO D O I
Su dung tu nhiet dm BK-NA2 tai Phdng Thi nghiem Ma sat hgc, Vien Co khi, Trudng Dai hgc Bach khoa Ha Ndi de tao mdi trudng theo TCVN 7699-2-30. Bd tii thiet bi tii nhiet dm BK-NA2 dugc thi hien ti-en hinh 5, diiu khiin tii dugc trinh bay tren hinh 6.
4.2.4. Che tao vd tich hop hi thdng thiit bi do mon vit me - dai dc bi
Hinh anh he thdng thiit bi thu nghiem mdn VMDB da chi tao dugc thi hien tren hinh 7.
Nhap:
'Ilioi giuii "T"
So chu innh "No"
Chu Uinhhicnlai'N"
sT^3-*l=l,-4a''. Rli, = 97%
<Tsl2-H°j-IO'iHH-93%
• T<ia-H''fl-JJMUI, = 90%
• Ts!4-4t°g-2S°;Hli,-!)7%
Hinh 6. So dd khoi dieu khien tu nhiet dm
Hinh 7: Hinh dnh hi thong thiet bi dugc che tgo J) Mdy vi tinh; 2) Bp dpc vd truyen so lieu;
3) Thiit bi do; 4) Bg diiu khien tu NA;
5) Tu nhiet dm; 6) Mdy thi nghiem;
7) Bp truyen dpng; 8) Dpng ca 5.2.5. Thuc nghiim ddnh gid h^ thong do
- Tdc do quay thuc cua true vit me dugc xac dinh thdng qua tin hieu thu dugc tu thudc do quayRE, dupe may tinh ghi lai va ve dd thi tdc dp quay theo thdi gian. Hinh 8 the hien tdc dp quay true vit me theo thdi gian trong mdt chu trinh d cac tdc do: a, 100 (vg/ph); b, 89 (vg/
ph); c, 78 (vg/ph).
Tir dd thj tren cho thay gia tti ky vpng cua tdc dp cung nhu bien dp thay ddi cua nd theo hai chieu quay eua vit me, can cu vao sd lieu thu dugc cho thay sai lech Idn nhat cua gia
tri do so vdi ky vpng < 5%. ^
NGHIEN CUU-TRAOePl
».o=100<vg.ph) b,D-S9(sgph) \
—Dw«4»-)»iii«W> '
• • ^ • ^ \ Clin
Hinh 8: Do thj tdc dp quay thuc cda true vit me trong cdc thuc nghiem - Tai dgc true dugc tinh qua ap suat dau do dugc F ^ p.S (p: Ap suat dau; S: Dien tich tiit dien budng dau ciia pittong - xilanh), may tinh ghi lai va ve dugc dd thi tai dgc tri^c theo thdi gian trong mpt chu trinh tinh tien khii hdi.
iLliSPWW>ri»'l^i V
Hinh 9: Dd thi tdi dpc true thuc te trong cdc thi nghiem
Can cu vao sd lieu thu dugc cho thay sai I8ch Idn nhdt cua gia tri do so vdi ky vpng <5%.
- Sai lech dgc true eua dai dc bi dugc xac dinh theo gia tri A^ = X^ - X^^; (X^ - Vi hi dai dc xac djnb theo RE; X^^ - Vi tti dai dc xac dinh theo LS). Cac gia tri do dupe cua RE va LS dugc dua vi may tinh de ve dd thi. Hinh 10 thi hien sai lech dgc tinic trong mdt sd thi nghi?m {dugc xac dinh qua chuyen vi cua RE va LS).
b. F=3000S. n=S9vg/ph a, F=3S00y. n=J0Ovg/ph
^F=3500N.n=100v«h. L->R nh (Encottar) %
I ' _F=3500N r,=,OO.M,h R..>L ^^ _F=3000N. « - ( » , « * . R->L
Hinh 10: Dd thi sai lech vj tri doe true cua dai 6c giica do bdng RE vd LS
Theo so lieu thu dugc tir thyc nghiem, sai lech vi tii Idn nhat ciia gia tri do so vdi ky vpng la ± I pm, bdng sai sd cho phep cua thiit bi do.
ISSN 0866 - 7056
TAP CHi CO KHi VIET NAM, Sd 1+2 nam 2015 www.cokhivietnam.vn
NGHIEN cufu-TRAO D 6 |
3. K E T LUAN
- He thdng thiit bi do mdn VMDB phu thude vao tai va tdc dp VMDB phii hgp vdi thyc nghiem theo diiu kien mdi tiirdng TCVN 7699-2-30 do he thing do mdn - do quay va do tiidng - hoan toan ben ngoai tu nhiet dm.
- Truyin dgng va tao tai trong thiet hi dugc danh gia cd dp chinh xac phii hgp vdi thuc nghiem do sir dung thudc do thdng va thudc do quay cho phep phat hien sai lech cd I pm.
- Sai lech Idn nhdt cua gia tri do so vdi ky vpng cua cac thdng s6: Tai, tdc do quay cho thdy hoan toan ndm ti-ong viing gia trj eho phep, sai sd dudi 5%, do do, thiit hi thu nghiem mdn BKM - VMDB20I4 dap iing dugc cac thdng sd cdn nghien ciiu.'t*
Ngay nhan bai: 22/12/2014 Ngay phan bien: 15/01/2015
Tfki U€u tham Idiao:
[1], Biii Quy Luc (2006), He thdng dieu khien sd trong cong nghiep. NXB. Khoa hpc va Ky thuat.
[2]. TCVN 7699-2-30 (2007), Thic nghiim moi tru&ng - Phan 2-30: Cac thu nghiem - thir nghiem Db :N6ng dm, chu ky (chu ky 12h+12h).
[3]. Pham Van Hiing, Nguyen Phuang (2007), Cas& mdy cong cii. NXB. Khoa hgc va Ky thuat.
[4]. Tran Due Toan, Pham Van Hung (2014), Experimental instrument and estimation method of axial wear of ball screw. Processding the 7th AUN/SEED-Net Regional Conference on Mechanical and Manufacturing Engineering 2014 (RCMME-2014). ISBN 978-604-911-942-2 pp. 181-184.
[5]. Tran Due Toan, Pham Van Hung (2014) Effects of temperature and humidity on wear of ball screw.
Processding the 7th AUN/SEED-Net Regional Conference on Mechanical and Manufactunng Engmeenng 2014, (RCMME-2014). ISBN 978-604-911-942-2 pp. 176-180.
ISSN 0866 - 7056
