I 1.1 v J \)v \J b) Tdn s(f
than lit 1/2, L2 hoar 3)_
2.4.1.3. l\lQt s6 VI dlJ
Cd cau 4 khau ban Ie va co cau tay quay - con truqt Iii nhfrng co cau thuemg duqe si'r d\lng trong che t'.1o may
Co ca'u 4 khJu ban Ie
Cd cau 4 kh5.u ban Ie gam 4 kMu, noi vai nhau qua 4 khdp, co the quay dao dQng quanh n6. Hlnh 2.28 the hi¢n m¢t 56 d'.1ng Cd cau 4 khau ban I~ duqc tht!c
,
hi~n bang cach thay doi chi6u diii cua d.c khau. a hinh 2.28 a, khftu 3 ch6t cling, nhu v~y vai chieu dai tUC1I1g doi eua minh kh.iu 1 va 4 co the dao d¢ng lac, nhung kh6ng xoay tron. Ca cau nay duqc gQi lit co eau ball Ie' 2 edn Ide. Neu rut ngan chicu diii kh&u 4 WC1I1g doi so vdi kh5.u 1, kha.u 4 c6 the quay (hlnh 2.28b) va khftu 1 thl co th~ dao dQng taco Cd diu nay dugc g9i lit co cau tay quay- can uk. TrUOng hgp kh&u 1 va 4 co cung chitu dui va d. hai deu co the quay (hlnh 2.28c) se t~o nen ((1 ulu hinll binI! hdnh . Bang each thay dtli kha.u co d)nh,
nguoi ta co th~ t~o nen m9t so dl,lng co cAu kMc.
Til cong thuc Gmchler, truemg hgp chuot co cau 4 khftu: so b~c tI! do F luon
Cu cd'u lay quay- con tntlJl
Ket cau nay gelm mQt tay quay noi vm m¢t thanh keo va mQt can truqt nhl1 hlnh 2.29. Dola mQt ket cau dQng CO" don gian. Vdi cau hlnh nay, khau 31a co
f:?J~ l ' '. . " .
a) b) ---. /
oj ---'
Hinh 2.28: C/1CQU 4 khdu ban Ie" a) b)
Hlnh2.29: Cdedu lay quay-con Intq1
dinh, tuc kh6ng co chuyen d¢ng tl10ng dai giua tam cua tay quay va than may, trang d6 piston trl1qt. KM.u 1 la tay quay, khau 2- thanh noi keo va khau 4 - can
1.wqt c6 the chuyen dOng t~nh tien so vOi. khfiu 3. Khi piston truqt tien- lui (tl1ong
Ung vm khau 4), tay quay -khau 1 bUQc phai quay. NhlI the CO" cau dli truy~n mQt chuyen d¢ng diu vao tlnh tien thanh m¢t
chuyen dong quay tron.
Hinh 2.30 the hi¢o CO" cau eulit Ide, la mQt
d~ng cua cO cau tay quay- can truqt duqe Slr dl,lng trang may M.a. Co cau nay g6m mOt tay quay- kha.u AB c6 the quay quanh tam quay A co d~nh ; mQt canh tay don CD c6 the daa d¢ng hlc quanh C khi c6 sl! tn1qt t~i B dQc thea CD khi AB quay, va kMu keo -DE co the bu¢c E chuyen d¢ng tm- lui. E
Hinh2.30: C/1nfu Clllil Me
ill dau tI"\lc chinh (can trl1qt), noi d6 c6 the lap bua de th,!C hi¢n wc nghi¢p. Bua sf: iJ q.i cac vi trf elfc diem khi v~ tri cua tay quay la AB\ va AB,.. Khi c.lnh tay quay chuyen dQog ngl1qc chieu kim Mng h6 tu Bl den B,., bua thl,fc hi¢n mQt hanh tflnh tac nghi¢p du. Neu tay quay tiep t\lc quay tu B,. den B, nglIqc chieu kim dClng h6, khi d6 bua l~i hoan thi¢n dl1qc ffi¢t h~l.Dh tdoh nhlffig thea hl16ng nglIqc l'.li- hi'mh t£lnh quay ve. Neu tay don quay v6i tac dQ co d~nh , thi do g6c quay cua tay don yeu cau cho hanh tdnh e6ng tac 160 hem sa v6i h~l.llh tdoh lui,
Cu C(i'll lay ql/ay - COil Iflfqr CO btjc tl/ do /=/.
Ring 2.2 the hi~n mf.jt s6 co cflu tay quay- thanh truy~n va m6i quan h¢ ve chuyen dQng, mornen, h!c giua cac phan tii cua co cflu vo-i. cac d<:ti iI.rqng dlIqc dinh nghia:
T- moment quay F- ngo~i Il,Ic
x-chuyen vi <po a-goc quay
cu-toc df.j goc 1- chic!u dili thanh
A - ti so giiIa chi6u dai cae thanh s6 I, 2 .. -kf hi~u khau ho~c chi tie't
Cacau
Tay quay -dn Ide
T,r::: W,
•
Tay quay -lhanh truytn
Tay quay-con INql x,
Bang 2.2: 1\19t s6 chuoi ca Call Ki hi~u
o o o
o - -
Moi quan h~ ham
({J2 =/( hill" Ilqc. ({J/)
T2 =/(Iu'nh hqc. T/)
+- Xl =j(xl , /,.I}> a)
-+
2.4.1.4. Truyen d~ng: cam
Cam la chi tiet co th~ quay tron hO~le dao d¢ng 10k de: truyen ehuyen dQng qua l:;ti (tjoh tien hai ehieu) ho~e ehuyto dQog hk cho chi tiet thu 2-
chi tiet b\ dan, hlnh 2.31. Khi cam quay, chi tiet bi dan dUQ'e nang lCn, ngu-ng l<;ti va t\!t xuong vdi khOllng thai giao wcmg ling ph\! thuQe vao cau hioh ella cam. Phan I¢ch tam - ban kinh l(m eua cam nang chi tiet bi dan lCn va phao I¢ch tam ban kinh nho h~ chi tiet xuang voi thai gian tuy thuQc vao hlnh dang cam. Vung cam gilC chi
tiCt bi di'm ti,li mQt muc khong d6i trong m¢t thai gian dang ke gQi la khoang ngu-ng. Vung nay cua cam thuang e6
ban kinh khong d6i (wang ling voi 'I 6 :/
khoang thai gian ngirng).
bl 0 A , 0 ) 'I V , I.)
llinh 2.31' Ballh cam vii
chi liet h! d/ill
~ ~l ,_. c ~l ,_. c ~ ~ ,~ 'w ~ '. ~ E 0 • ," o , > .. ffi~ '" ' ~ 0 , • '. ,", ~' Vcing quay cam
~!r-,
' - - -! !
W ,~ "= -
Hlnh dang cua cam dllQ'C yeu du de sinh ra ehuyen dQng dinh trucK eua chi tiet bi dan. Hinh dang cam nhu hlnh 2.32a, mQt cam tron nhung co tam quay l¢ch. cho phcp chi tiet bi dan co chuyen dQng dao dQog dieu hoa, lo~i thuang dtIQ'c sir dy.ng trong ket cau eua bdm. Cam d hlnh 2.32b. co hlnh d<;tng tnii lim, khi quay cho phep chi tiet bi dan djch chuyen len voi toe dO co dinh trong mQt khOllng thai gian,
Hinh 2.32: M(II s6' hinl! dall)!, cam vd