Tgp chi Khoa hgc - Cong nghe Thuy sdn

Tgp chi Khoa hgc - Cong nghe Thuy sdn So 3/2014

THONG BAO KHOA HOC

MO HINH HOA CO CAU CAM GLOBOIT CAN QUAY TlT CHUONG TRINH GIA C 6 N G DIEU KHIEN SO MODELLING GLOBOIDAL INDEXING CAM FROM IT'S NC PROGRAM

Nguyin Van Tuong' Ngay nh?nbai: 07/5/2014, Ngay phan hi^n thong qua: 20/6/2013; Ngay duy?t (tang. 13/8/2014 T O M T A T

Bdi bao trinh bay vi^c mo hinh hda ccr cau cam globoil cdn xoay vai con ldn Iru. DO- lieu chinh diing cho mo hinh hoa Id chuong trinh dieu khien so 5 trifc gia cong ca cau cam ndy Oday, cdc gid tri true xoay trong chuang trinh gia cong duac chuyen thanh cac gtd tri dfch chuyen goc xoay dau vdo cua cam vd ddu ra cita cdn. Tit cac gid Irj ndy, tpa dp diem pitch tren cdc con lan dup'c xdc dfnh nhdm xay difng m^t pitch ctia cam. Be mat ldm vi^c aia cam nhan duac bdng cacli offset be mdt pitch Trong nghien ctiu ndy. phdn mem Pro/ENGINEER Wildfire 4 dup'c su dung de Ihuc hi^n mo hinh hoa ca cau cam vd kiem tra giao thoa giua cam vd cdc con ldn

Tir khoa: cam globoit. mo hinh hoa. Pro/ENGINEER Wildfire A B S T R A C T

This paper presents a case study of modelling the globoidal indexing cam with cylindrical rollers. The main data for modelling is the 5-axis numerical control (NC) program that used lo machine the cam. Here, the values of rotational axes in the NC program are converted to the input and output angular displacements of the cam and the follower From these displacements, the coordinates of the pitch points on the rollers, and then the pitch surfaces, can be defined The working surfaces of the cam can be obtained by offseling the pilch surfaces. In this study, Pro/ENGINEER Wildfire 4 is used for modelling the cam and checking interference between the cam and its rollers.

Keywords • globoidal cam. modelling, Pro/ENGINEER Wildfire I. DAT V A N Qt

So sdnh vdi cac ca c l u cam khac. ca eau cam glflbflit cd dgc tinh Id rat chac ehan, cd khd nang mang t i i eao, tdm vipe em vd cd dfl tin cdy eao. Vi t h l ca c l u ndy dupc diing rflng rdi trong eac thilt b] ty dflng trong cdng nghipp. Cde trng dyng dtin htnh eua ea elu cam Id trong may cdng ey. ede ddy chuyin l i p rap ty dflng, mdy dong gdi vd nhieu thilt bl ty dpng khde [6],

Cho den nay da cd nhilu cdng trinh nghifin eiru v l cam glflbflit bao gom md htnh hda ea eau cam, tinh todn dpng lye hpc, gia cdng ca cau cam trfin mdy CMC (Computer Numerical Control)..

H l u h i t cde nghifin eiru ndy deu khdi dau bing vipe mfl td b l mgt ldm vi0c cua cam vd xdy dyng mfl htnh CAD {Computer Aided Design) ba chieu ctia cam. B l mdt tarn viflc cua cam Id b l mdt cam ttip xiic vdt con lan khi ea c l u tdm vi$c. tvlflt so

cdch tiep can da dupc ede nhd nghien euu th^'c hipn de mfl t i cung nhu xdy dyng b l mgt lim vi^c ciia earn globdit nhu sau:

- Bilu dien phuang trinh toin hpc cOa be in|it idm vific cua cam glflbflit bang ede eong ey todn hpe nhu: biln d i i hfl tpa dfl. hinh hpc vi phin vd ly thuylt tgo mdt ttfin hpp Cde nghten cuu dien hlnti eho cdch tilp c i n ndy l i nghifin cuu eiia Cheng [2], YanviChen[9]. [10],

- SO' dyng mdt s6 phin mem do hpa thuang mgi nhu AutoCAD R14 vd 3D Studio va ngon ngO lap trinh VBA fli phit tnln mpt gfli phan mlm de tgo be m^t lam vi^c cda cam gidbdit v i tgo mo hinh cam gidbdit [3].

- Be mgt ldm vigc cua cam globdit dupc bieu diln thflng qua b l m§t qudt dupc tgo bdt du'dng chgy dao khi sd dgng dao cd kich thudc va hinh ddng giong nhu eon Idn [7],

' TS, NguySn Vdn Tudng: Khoa Ca khi - Tnfdng D^i hpc Nha Trang

84 • TRLTONG DAI HOC NHA TRANG

Tgp chi Khoa hgc - Cong nghe Thuy sdn

- Theo quan dilm gia cdng, b l mdt l i m vific ciia cam c6 t h l dup'c xdc dinh khi bilt sy djch ehuyen tuang ung c^a ciia cam vd cua khiu bj d i n [4]. Dya vdo quan diem ndy, Tudng vd Pokomy [8] da xdy dyng mo hinh ca c l u cam glflbflit khi bilt tnidc quy lugt gdc quay cita cam v i gde quay ciia d n l i e tifong dng.

Trong nghifin ct>u niy, md hinh ca d u cam glflbflit d n quay cung duvc tgo ^ e o quan diem gia cdng. Tuy nhien, d day, du hdu d i u vdo de tgo mfl hinh Id chuong trinh NC diing de gia cdng ca d u cam glflbflit d n quay dupc tgo cho mdy chuyen dimg. Md hinh CAD ciia cam dupc tgo ra cd t h l

Hinh 1. Cam globdit lof i c6 ranh

Hinh 3 b i l u dien ede moi quan h# hinh hpc giifa cam giflbdit ldm vdi d n ldc. Trfin hinh ndy, mgt chuin Id mgt phing chira trgc d n lac vd vudng gdc vdt trye cam, cdn mgt khai triln l i mdt

dupc dting cho c i c dng dgng khde trong thilt ke vd ehe tgo cd sy ho try cua mdy tinh.

II. oOi T u g N G vA PHiroNG P H A P N G H I D N CCPU 1. Ca cau cam globdit

Cd hai loai ca d u cam gidboit. Trfin hinh 11d logi cam glflbflrt cfl ranh trdn ^ d n cam vdi ckn cd chuyin dflng lac ( d n ldc). Thdn cam cd dgng b^ mgt cam lit (hinh la) hogc b l mgt torn (hinh 1b). Logi thu hai ed mpt hogc nhieu gdn tren be mgt cam vai hai dgng d n tic (hinh 2a) hoac d n quay {hinh 2b). Trong bon logi k l trdn thi logi cam giflbdit d n quay cd hinh ding phifC tgp nhat. kho tao md hinh nhat.

W (bl Hinh 2. C a m globdit loai co gan

phang bat ky vuong gdc vdi true con lan. Diem pitch Id giao dllm cua trgc con l i n v i mgt phdng khai triln. C i c thdng so hinh hpc eiia ca d u ndy nhu sau [4]. [5]-

Dahimplane -»-- —-fr^— - ^ s . ^ - — • • - — y ^ —

Development pleme

Hinh 3. M6i quan hf binh hga giira cam globoil \k can a - goc quay cua cam.

b - goc quay cua can luang iing voi goc a:

l/'goc hflp bm mgt phA^chuan vol oyc con lan Iren kkihtliiongavjirl ban ddu:

f - ^c hgp bai Iryc con lan tren vai m4l phang chuan:

b' - goc li(q> bai tnfc con ton dual vai mqtphSng chuan I - Umangcach lirlryccan lie 4en dau mui cia con ldn, I- chieu ddi con Idn.

e - khe ha glUa dou mut con ldn vdi than cam.

F - khoang cdch lir Iryc can lic den diem pitch.

C - khodng each giiia mtccam vd trye can lac:

R - khoang cdeh til diem pitch den trye cam. R'^C- F.cos(b'J, (I) h - khodng cdch tii diem pilch den mgl phdng chudn. h - Fsin lb') (2) Cde ihong so a. I. e. I khong dagc the hiin Iren Hinh

TRUONG DAI HOC NHA TRANG • 85

Tgp chi Khoa hgc - Cong ngh4 Thuy sdn S6 3/2014

Moi quan hfl hinh hpc giua cam glflbflit vd d n

l i e nfli trfin cung cd t h l dupc dp dyng trong trudng hpp cam gidbdit d n xoay.

2. Phuo'ng phdp md hinh hoa

Khi ca d u cam glflbflit Idm v i ^ tht tnjc con ldn se vgeh nfin m^t mdt k l trong khdng gian [7]. Ddy ehinh Id mgt pitch ctia cam, tuc Id bten dgng cam ty thuyet. B l mit lim viflc ctia cam se dupe xdc djnh tir mat pitch ndy bing cdch tgo mgt offset tir m§t pitch vdi lupng offset bing b i n kinh con ldn (hinh 4).

Gde b l m|t khic ctia cam cfl t h l dupc tgo ra sau khi tgo xong c i c mgt l i m viflc ctia cam.

p - 1, Conlan

* ^ midmviSe

^\^y^Mgtpitch

KEitldmviSc

Hinh 4. Nguyen 1^ t^o cie bk m | t U m vi^c ciia cam glSbfiit c^n quay

Nhu vgy, neu tgo dupc m$t pitch tht cd t h l tao dupe b l mat Idm vific cua cam. Mit pitch cfl t h l dupc tgo bang cdch qudt mflt dogn thang tnjng vdt tam ctia con ldn [8], Hat dilm dau cua dogn thing phdi tya trfin hai dudng cong. Dudng cong thir nhit l i qu? tich ctia tdm 0 cua d n khi xet cam ddng yfin va can xoay xung quanh cam. Dudng cong thir hai Id dudng eong td quy tich cCia dilm pitch P khi xet cam dirng yfin vd d n xoay xung quanh cam, Nhu v i y dudng (X)ng thu nhat Id mpt dudng trdn cdn dudng cong thd hai Id dudng cong khdng gian 3 chteu.

•Duong cong 3D

f)oQn thdng quel

Hinb 5. Nguy§n 1^ tao mit pitch Tpa dfl cCia dllm pitch dupe tinh nhu sau 18]:

h' = F.sinp' (3)

R" = C - F.o (4) (5)

Trong dd: i = 1. 2, tuang ung vdi hai b l mgt pitch ctia hat ranh;j = 1,2...., n, tuong tfng vdi cac gtd tri gflc quay etia d n .

3. Chuang trinh p h i n mem KIN

Chuang trinh phan m l m KIN dupc phdt trien bdi Vi$n Nghifin ctru Miy dflt VUST d Liberec. Cflng hfla Sdc. Ddy l i chuang trinh phin mlm chuyen dyng dupe dilng d l gidi cdc bdi toin dflng hpc cb lifin quan d i n vi^c thilt k l cdc h0 thing cam [4], Phin m l m niy cd t h l tgo chuang trinh gia cong mflt s6 logi cam khac nhau. Phien ban phin mem KIN dupc diing tgt Cflng ty ZZ-Antriebe (Due) cb thdm mfl dun tgo chuang trinh gia cdng ca d u cam glflbflit diing eho mdy chuyfin diing PRAWEMAV^

tgo mflt s6 Itfpc do mfl ta sy b l tri cde ranh tren cam. KIN khdng tgo dupc md hinh CAD ba chilu c i i a c a d u cam.

Chuang trinh gta cflng cam glflbflit d n quay dupc xuat ttr phin m l m KIN Id chuang trinh gta cflng 5 true cho may cfl 3 trgc chuyin dflng thing X, Y, Z vd hai trgc quay A vd B. Trong dfl, A Id gflc quay cua chl tilt gia cflng cfln B Id gflc quay eiia dao.

Dao dupc str dgng de phay ranh cam Id dao phay ngon cfl dudng ktnh bing b l rflng rinh. & pha bbc vgt lifiu etia chuang trinh gia cong, cdc cdu Ifinh chi gdm thdng tin v l hai gdc xoay A vd B trong h§ tpa dfl tuang dfli. Nhu vgy, neu eoi dao nhu mflt con Idn ciia d n quay tht cd t h l xem A Id gflc quay a ciia cam vd B Id goc quay b ctia d n , khi dfl cfl thi chuyin ddi cdc g i i trj gflc A vd B trong chuang trinh gia cdng thdnh cdc gflc a vd b cua ea d u cam de tinh tpa dfl diem pitch nhd cdc eflng thirc (3) vd (4) d trfin Tir cdc tpa dp ndy, cd t h l tiln hdnh xiy dung xdy dyng be mdt lim vi#c ctia cam theo phu'ong phip da dupc mfi ta d mgc 11.2.

111. KtJ QUA NGHIEN CLPU VA T H A O L U A N 1. V i d u dp dung

Xdy dyng md hinh CAD ba chteu ea clu cam globdit d n quay vdi 6 eon lin trg tir chuang trinh gia cflng dupc tgo bdi phin m l m KIN. Mflt sfi thdng s6 hinh hpc ciia ca cau Id d = 25.4 mm, I = 17 mm, C = 118 mm, t = 59,5 mm, e = 1.5 mm Trong chuang trinh ndy, pha gia cflng m6i rdnh c6 745 cdu Iflnh. Mflt so dogn trong chuang trinh ndy nhu sau:

86 • TRUONG DAI HQC NHA TRANG

Tgp chi Khoa hgc - Cong nghg T^idy sdn

-67.3831 [Grad]

;Program No.: x0670

;Starting point: A= 196.50 8=

GO G90A196.50 B-67.3831 GO ZO M3

G91Z-17.000M8H1 M10

Gl G91 G28 FE25

;* 1. Groove * N100 A0.50B0.6471 N101 A0.50 80.6438 N102 A0.50 80.6403 N842 AO 50 80,5531 N843 A0.50B0.5479 N844 A0.50B0.5427

;End value 1. Groove A= 209.00 B= 67.5842

;Start value 2.Groove A= 151.00 B= -67.5842 G0G91

KIN edn tao mpt so lupc dd ctia cam nhu trfin hinh 6

Hinh 6. M^t s^ lirgrc del cu C i c tinh todn d n thilt cho vlflc tgo md hinh Id:

- Chuyin ddi cic gid tii djch chuyin gdc quay ciia cam vd d n tir tpa dfl tuang d i i sang tpa dp tuy#t dot.

- Tinh cde gdc p cho hai be mdt pitch tuang ung vdi hai ranh. Gflc jS^dng vdi hat ranh l l n lucrt l i -67.3831 " v i -67,5842°.

- Tfnh tpa dfl S i m pitch cho d hai m#t trong h# tpa dp tnj vdi ba thdng so Id gde, bin kinh va dp eao. (y d i y chpn dilm pitch d vj trf cd F = 60 mm (hinh 3).

T i t d cdc phdp tfnh dupc thyc hi$n vdi Microsoft Excel.

2. C i c bipdv md hinh hda vd k i t q u i Trong nghifin ctfu niy. phin mlm Pro/ENGINEER Wildfire 4 dupc sii' dgng d l tgo md hinh

M09M11 Z27.000 A-58.00B-135.1685 Z-27.000 M8 M10 Gl G91 G28 FE25

;' 2. Groove * N846 A0.50B0.5427 N847 A0.50 80.5479 N848 A0.50B0.5531 N1588 A0.50 80.6403 N1589 A0.50B0.6437 N1590 A0.50B0.6471 .End point A=163.50 8=67.3831 G0G90

M9M11 HO M2

cau cam glibSit c^n quay

ea d u cam. Cac budc chinh de thyc hipn tgo md hinh cam Id:

(a) Tgo cac dilm pitch va dudng cong quy tich ciia chting;

(b) Tgo quy dgo goc Id dtfdng tron ed ban kinh bang khoang edeh tir trye d n quay din trye cam;

(e) Tgo cic mgt pitch v i cdc mgt offset v l hai phia mgt pitch, lupng ofteet bdng bdn kinh con tan;

(d) Tgo mat tron xoay eua than cam;

(e) Tgo c i c mgt phu nham Idm kin cdc mgt vdi nhau cho tirng be mat Idm vipc;

(f) Ghdp cdc mat vdi nhau vd chuyen vdt t h l mit sang vdt t h l die;

(g) Thyc htfln mpt so tpnh d t de cd hinh ddng cam theo yfiu d u .

Hinh 7 trinh bdy k i t qua ctia mflt s6 budc mfl hinh hfla.

TRUONG OAI HOC NHA TRANG • 87

Tgp chi Khoa hgc - Cong nghe Thuy sdn So 3/2014

Cdc diem pilch vd dudng cong Cdc dudng cang tgo rnqtpitch Mdt pitch tha nhdt

1^ WS.

M^tpitch Ihi nhat vd 2 mdt offset Mo hinh hoan chmh

Hinh 7. K^t q u i m$t st baitz m5 binh b6a Gde xoay ciia cam trong so lifiu dau vdo Id rdi

rgc do dfl cd t h l stnh ra sai s6 khi tgo mgt pitch vd vi the cfl the gdy nfin sai Ifich v l hinh ddng v i kfch thudc ciia cam. Cae tinh huong ed the xdy ra trong lap rdp cam vd con lan Id: (1) cd giao thoa giiJa cic b l mat Idm vific cua cam vd mat trg cua cic eon ldn,

Cam

tire CO xung dflt tnDng lip ghdp vd h0 thing khfing Idm viec dupe, {2) ed khe hd Idn giua cdc b l mat lam vi0c cOa cam v i b l mit tn^ ctia cdc con lan, va (3) trong mflt vdng quay eiia cam cd mflt sfl vj tri xdy ra giao thoa vd mpt s l vj tri xuat htfln khe hd Idn giira bS mdt Idm vipc cua cam vd mat fail cGa con tan.

Con i§n

Servo motor 1 Setvo motor 2 Hinh 8. Cic

Vipe kiem tra giao thoa giua hai chi tilt cOa ca d u cam ed t h l dupc thyc hifln t y dflng trong mfli trudng mfl phflng ehuyen dflng ciia PHD/ENGINEER Trong trudng hpp khflng xiy ra giao thoa thi d n kilm tra tilp khe hd. Vipc kilm tra khe hd ndy dupc tiln hanh thdng qua chdc ndng do khoing cich nhfl nhit giifa cdc d i i tupng ctia Pro/ENGINEER.

Khi thyc hipn md phflng chuyin dflng, trgc cam vd trye d n quay duac gin cic sen/o motor (hinh 8).

VI cam quay vdt toe dfl khflng dot nfin c»} the diing

• TRUONG OAI HOC NHA TRANG

serco motor

tiiy chpn bien dfl bang hang so eho servo motor 1 cOa cam. Chuyen dflng eua servo motor 2 ciia d n cd t h l dupc djnh nghTa bing mflt bdng so li§u bao gom cdc gid trj tuang ung ciia cdc gid trj djch chuyin gflc quay ciia cam vd d n da dupc xdc djnh trong qud trinh tinh toin cho viec tgo mo hinh.

Trfin hinh 9 Id kit qua md phflng chuyen dflng cua cam vd d n trong lap ghep. Trong mflt vdng quay cua cam, khdng cfl giao thoa giu'a cam vS cdc con lan d n trong l i p ghdp. K i t qud kilm tra

Tgp chi Khoa hoc - Cong nghe Thdy sdn So 3/2014

cho thiy khe hd Idn nhit giua be mdt Idm vipc ciia

cam vd be mat try cua cdc con lan cung rat nho (nhd han 0,2 pm). Khe hd ndy da nhten gdy ra sai s l djch

chuyin gdc cua d n tuy nhifin sai so ndy rit nhd vd cd the chip nhdn dupc. Do dfl eo t h l kit luin rang md hinh CAD da tgo dat do chinh xdc yfiu d u .

eg SURFACE1ASM . - O BROU£R-SUR PfiT U p BSUBFAajfll S - X MECHANISM

\ - ^ 6RAVIIY S 0 COHNEatONS S sl MOTORS

'. JJ_ SffllNGS

> X DAMPERS

; - ^ FDRHS/TOBQUE' a ; INITIALCONOIIICs,

.«'

mnh 9. Kit qui mo pb6ng IV. K^T LUAN VA KliN NGHj

Cd fill tao md hinh CAD cua ca d u cam gidbdit d n quay tCr chuang trinh gia cdng dieu khien so dupc tgo ra bdi phan mem KIN. Cdc gid trj gde xoay trong ede edu Ipnh ciia chuang trinh gia edng ca d u cam duac chuyin d i i thanh cdc djch chuyen gdc eiJa cam vd d n . Day Id eic thflng s l d i u v i o quan trpng d l thyc hien cdc tinh todn tao dd lifiu cho vific md hinh hfla. Dfl chinh xae cua md hinh duyc kiem tra thdng qua vific kilm tra giao thoa

chuyen dpng cua co cau cam

giua ede b l mat Idm vific etia cam v i cac con ldn eung nhu khe hd giifa chiing trong ldp ghdp.

Trong nghifin ciru niy, vipc tgo mfl hinh, kiem tra giao thoa v i khe hd eo t h l thyc hi#n vdi phin mem Pro/ENGINEER Wildfire 4. Md hinh CAD dupc tgo ra cfl t h l dupc dung cho viee tinh todn ky thugt cfl sy h i trp cCia miy tfnh trong qud trinh thtet ke eung nhu lap trinh gia edng bang mdy tinh d l gia cdng ea d u cam gidbdit trfin trung tdm gia cdng hogc mdy da chirc nang.

TAI LIEU THAM KHAO

Chen S. L., Hong S. F., 2008. Sur&ce generation and fabncation of roller gear cara with sphencal roller. Joumal of Advanced Mechanical Design, System, and Manufacturing, 2 (3): 290-302.

Cheng H. Y., 2002. Optimum tolerances synthesis for globoidal cam mechanism. JSME intemational Joumal, series C, 45 (2): 519-526.

En-huiY., Chun Z.,Ji-xianD., 2001. Creating surface of globoidal indexing cam profile on computer. Joumal of Northwest University of Light Industry, 19 (1): 4 M 3 .

4. Koloc, Z., Vaclavik, M., 1993. Cam mechanism. Publisher of Tcchincal Literature of Prague, Prague.

5. Reeve J., 1995. Cam for mdustry Mechanical Engineering Publications, London

6. Sanap S, Jagtap'K., Nanduritar K., 2013. Design and Analysis of Globoidal Cam Index Drive. International Joumal of Scientific Research Engineering & Technology, 2 (3): 163-168.

Tsay D. M., Lin S Y., 2006. Generation of globoidal cam surfaces with conical roller-followers ASME 2006 Intemational Design Engineering Technical Conferences & Computers and Information in Engineering Conference, Philadelphia, USA, DETC2006-99683

Tuong N.V., Pokomy P., 2008 Modeling concave globoidal cam with swinging roller follower a case study. Proceeding of World Academy of Science, Engineermg and Technology, 32: 180-186.

9. Yan H. S., Chen H. H., 1994. Geometry design and machining of roller gear cams with cylindncal rollers Mechanism and Machine Theory. 29 (6): 803-812.

10. Yan H. S., Chen H. H , 1994. Geometry design of roller gear cams with hyperholoid rollers. Mathematical and computing modeling, 22 (8): 107-117.

TRL/ONG OA! HOC NHA TRANG •