- Bao tri, bao duong duqc may nen khf va thiSt bi phan ph6i khf nen.
3. CAU TAO TfNH TOA.N MQT XY LANH a Cdu t~o
a. Cdu t~o
I g P====:::i
I I
19-f·~: I I
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M9t xy lanh kitefu piston duqc cdu thanh boi m9t than, m9t day va m9t niip phfa cJn, m9t piston cung vai d?m cua n6 (d?m kitefu don tay kep), m9t cJn piston, m9t br.;1c, m9t d?m chiin va m9t s6 chi tiet noi cung vai cac vong d?m.
Than xy lanh (1) c6 cffu tr.;10 chung la m9t ong thep keo khong han. Dtef tang tu6i thQ cua cac mieng d?m, b§ mijt truqt cua than thudng duqc mai sieu tinh. Trang mQt so
truang hqp than cluqc lam bling nham, c16ng thanh, hoijc 6ng thep, Jue biy gicJ b~ mijt trLl(Jt cJuqc me} cram. Cac kieu nay cJuqc SU dl}ng trong thljc te de baa V? xy lanh khang bf mai mon i) giaa. Tuy nhien xy lanh ctlng khang nen lam Vi?C lien tl}C.
Day (2) va nJp phia c.in (3) cJuqc clue. Day va nJp cluqc lien ket v(Ji than bling thanh giling, vit hoijc mijt bich
C.in piston (4) cluqc LIU tien che tc}0 bling thep cJa gia cang nhi?t. De ngan ngua sl/ rl thep nay c6 chua vai ph.in tram cram. De tranh bf gay, ph.in cJt ren thuang cluqc che t?o bling phuang phap Ian ren. Vai giai phap tren, c.in piston c6 the nhi?t luy?n. Bling each ch?y ra nguai ta c16ng nhit hoan toan cac b~ mJt, b~ mijt cua c.in piston giam bat J □m. Khi lam Vi?C tiep xuc v(Ji nLfcJC th, c.in piston phai cluqc me} hoijc toi.
De baa clam cl{) kin iJ c.in piston, nJp phia c.in phai cluqc trang bf m{)t cl?m c6 mep kin (5). SI/ d.in huang cua c.in piston cluqc baa clam bling b?c (6), b?c nay c6 the lam bling c16ng thanh, thuy tinh hoJc kim lo?i cluqc phu m{)t lap V?t li?u tong hqp.
D?m kieu don tay kep chJc chJn, baa clam cl{) kin cua than. V?t li?u thuang dung:
■ Perbunan tu -20°C den so0c
■ Viton tu -20°C den 190°C
■ Teflon tu -B0°C den 200°c
De baa clam cl{) kin tTnh, nguai ta su dLJng cl?m Profin va cl?m hrnh xuyen. D?m profil baa clam cl{) chinh xac va cac lo?i cl?m nay su dLJng cl{)ng life de thl/c hi?n bai trefn giam ma sat.
9 8 2 2 b. Tfnh toan -Life cJdy 4 5 7 3 6
Llfc diy sinh ra khi xy lanh ho9t d9ng phv thu9c vao ngu6n ap suat duang kfnh xy lanh va ma sat cua cac d?m
Llfc diy ly thuyet duqc xac djnh theo cong thuc sau:
trang d6:
Fth =A. p . □
Frh - Llfc dJy ly thuyet (N)