Bi1: g lp kt cu tm phngI. Mc tiu ca bi: Sau khi hc xong bi ny ngi hc s c kh nng: - Trnh by ng cc loi g g cc kt cu tm phng. - Chun b phi hn m bo cc yu cu k thut. - Chun b thit b, dng c dng nh v, kp cht, v kim tra kt cu hn y , hp l. - G phi hn chc chn, ng kch thc, m bo v tr tng quan gia cc chi tit hn ch mc bin dng trong khi hn. - Kim tra kt cu hn bng cc dng c o kim, pht hin c sai s v kch thc v hnh dng.

- Chnh sa kt cu hn m bo chc chn, ng kch thc.Bi1: g lp kt cu tm phng1. Vt t.II. Cng tc chun b: - Phi hn thp tm CT3 , S= 4mm- Que hn E42 3,2 mm 0,2kg2. Thit b: 2.1. My hn In mt chiu, xoay chiu:

2.2. My mi cm tay: 2.3. H thng bn hn

3. Dng c:2.4. Bn mt, e phng, t3.1. Cc dng c phc v ngh hn

3.2. Cc dng c o: Thuc dy, thuc l, thuc vung, thuc o gc, com pa cc c, dng kim.3.3. Cc dng c vch du: Mi vch, chm du, com pa 3.4. g hn: 3.4.1. Mt s khi nim: - nh v chi tit hn: - Khi nim g hn: L dng c dng gi cc b phn ng v tr trong qu trinh hn; nhm nng cao chnh xc v tng nng sut lao ng. m bo chnh xc ca chi tit hn trong khi hn cc b phn phI gi ng v tr tng quan vi nhau. V vy nh v l xc nh v tr tng i ca chi tit hn so vi kt cu hn

- Nguyn tc nh v: + Chuyn ng ca vt rn trong khng gian: Mi vt th trong khng gian c th chuyn ng theo 6 hng c bn

- Nguyn tc nh v 6 im: Kho st mt chi tit c dnh hnh hp t trong h ta OX, OY, OZ.

+ Trn mt phng ca hnh hp EFKH dng 3 im ta s hn ch 3 bc t do gi l mt nh v chnh im 1: Hn ch bc t do tnh tin theo OZ im 2: Hn ch bc t do quay quanh trc OX im 3: Hn ch bc t do quay quanh trc OY+ Mt bn ADHE gi l mt nh hng, im 4 v 5 cng xa nhau chi tit cng cng vng.+ Mt DCKH lm mt 1 bc t do tnh tin theo trc OY, mt ny gi l mt nh v chn. Mt ny cng nh chi tt cng c nh v chc chn. Vy 1 chi tit hn ch c 6 bc t do gi l nh v hon ton nu mt bc t do no hn ch 2 ln gi l siu nh v. Trong gia cng khng phI lc no cng hn ch 6 bc t do m ty theo yu cu ca chi tit gia cng .

3.4.2. Phn loi g: 3.4.3. Cc thnh phn ca g hn: - g chuyn dng.- g vn nng.- nh v: l cc phn t xc nh v tr ca chi tit hn vi c g+ Cc kiu nh v: ngn, tr chng c nh tho c, bn l, cht v nh nh v, cc khi V iu chnh c v dng.

+ Cc loi nh v thng dng: cht t, phin t, khi V3.5. B tp, cl chuyn dng tho lp m hn, g hn - kp: l cc phn t ca g m bo s p gia cc chi tit i vi cc nh v hoc cc mt chi ti ca g. kp c cc loi:C kh (Bu lng- ai c, vam, ch C), Kh nn, t v thy lc.

- Tm phng khng vt mp.1. c bn v:III. Trnh t thc hin:- Khe h gia 2 chi tit 3 mm- Kch thc kt cu hn: 143 x 83 x 4 (mm)- Mp ngoi vo Im g khong 10 (mm)- Khong cch mi Im g 100 (mm),70(mm)- Mi hn g 10 (mm)- Khi hn g theo th t I,II,III,IV. - Chiu cao mi g khng c cao qu khong 3(mm)

2. Chun b phI: - Kim tra kch thc phi. - Lm sch dc theo mp hn hai bn khong 20mm trc khi g 3. Tnh - chn ch hn. Ch hn nh h quang tay c xc nh nh sau. a. ng knh que hn p dng cng thc: (mm). chn 3,2 mm. Trong : (d) ng knh que hn, (S) chiu dy vt liu b. Cng dng in hn: Tnh theo cng thc h = ( + d) d (A) . h = (20+ 6x3,2)x3,2 = 125.5 (A), Chn 130 (A)Trong : Ih l dng in hn v l h s thc nghim, =20, = 6. d l ng knh que hn.

C. in p hn: Uh = a + blhq + (V) Trong : Uh -l in p hn (v) lhq - l chiu di ct h quang t 2-4(mm). Chn 3(mm) Ih Cng dng in hn (A). Chn 130(A) a - l in p trn a-nt v ca tt (a= 15 20 v). Ly 20 (V) b - l in p ri trn mt n v chiu di ca ct h quang (b= 15,7v/cm) c v d cc h s (c= 9,4v , d= 2,5 v/cm) d. Vn tc hn. Vh = (m/h)

Trong : - l h s p gip mi (811 g/A.h) F - L tit din p (cm2) l trng lng ring ca vt liu hn (i vi thp = 7,85 g/cm3) Ih Cng dng in hn (A) 4. Tnh vt t : - Phi hn 323x40x4x7,85 = 0,84kg - Que hn E6013 3,2mm 0,1kg - t chi tit 1, 2 v 3 ng im nh v trn g. - Khe h gia hai chi tit khong 3mm. 5. nh v kt cu. - V tr nh v khng b x dch- Kim tra kch thc kt cu sau khi t vo v tr nh v

6. Kp cht kt cu - Sau khi t lin kt ng v tr nh v. - Vn nh ai c vu kp t ln chi tit - Kim tra v tr nh v khng b x dch vn bu lng chi tit, kt cu kp cht.

- Khi kp cht m bo //, vung gc - Khe h gia hai chi tit thng, u m bo 3mm7. Hn nh: * Hn nh hai u - Iu chnh ch hn thch hp. - Hn Im th nht (Im 1) cch mp ngoI vo khong 10mm.

- Tin hnh hn Im th hai (Im 2) cng cch mp ngoI vo khong 15mm. Sau hn Im (Im 3) khong cch g hai Im bng 100mm. Chiu dI mi hn g khong 10mm. - Mi hn g ngu, chc. - im g khng c cao qu khong 3mm * Hn nh im gia: Sau khi hn hai im hai u tin hnh hn im (Im 3) khong cch gia hai Im bng 100mm. Chiu dI mi hn g khong 10mm.

- Khi g im th 3 lun ch khe h 2mm. 8. Tho kt cu.- hn ch s bin dng kt cu, phI ngui ht s bin dng nhit mi tho kt cu ra khi g hn.- Vn t t ai c.- a kt cu ra khi g hn.- Nu kt cu c kch thc ln phi g c hai mt

9. Lm sch x,.- Lm sch x hn, ly ba g x nh sch lp x trn b mt mi hn im, sau dng bn chi st lm sch.10. Kim tra: (Hnh 1-10)- Dng thc kim tra kch thc- Dng dng kim tra kch H.1-10 thc mi hn g- Dng ke vung kim tra vung gc ca lin kt

IV. Nhng sai hng nguyn nhn v cch phng nga 4.1. Lch tm:* Nguyn nhn - Ih qu cao- Im g khng u.- Khng tun th v tr nh v, v tr kp cht- Tho kt cu ra khi g khi cn bin dng nhit* Ngn nga:- Chn cng dng hn ph hp- Xc nh li khong cch Im g- G ng v tr xc nh- Tho kt cu khi ht bin dng nhit

4.2. Kt cu b xon.* Nguyn nhn- Cng dng hn ln- Kp khng cht- Im g khng u * Ngn nga:- Iu chnh li ch hn.- Khong cch Im g u- Kp cht kt cuV. An ton khi g:- Khi hn g lun dng knh hn- Bo h lao ng y - g chc chn, an ton My hn khng r In- Nn xng kh ro khng m t.