Equation - Design Table Trong SolidWorks
Equation:Trong trng hp nhng tnh ton trc tip ch lin quan n cc kch
thc m hnh th ta c th dng cc cng thc iu khin chng cho n gin.Theo nh
iu kin rng buc ca cu lchiu di dy ai khng i, ta thy cc yu t tnh ton
y trc tip l t cc kch thc ca m hnh, vy nn dngEquation(cng thc) iu
khin.u tin, ta dng phc tho nh sau:Sketch ny cc yu t xc nh hnh hc,
vy nn n c mu en. Lu rng tm hai pulley thng hng theo chiu ngang, tt
nhin ta c th khng bt buc dng nh vy, song khi cn c thm to cc pulley.
Thc ra bn cht ca bi ton l xc nh khong cch trc 2 pulley ny, nn ta c
chng ngang hng cho tin. Mt lu na l chiu di hai nhnh dy ai chy bn
ngoi cc pulley lun lun bng nhau, d cc puley ny c thng hng hay khng.
Nu ta nhnh trn di 400mm th nhnh di cng di ng nh vy. Cc bn c th cho
rng iu ny l l tng, ch thc t th nhnh b dn s b vng v di hn cht t. Nu
qu l nh vy th cng OK, ta s v n vng xung v ly thm kch thc bn knh
cong. Nhng v y l v d, ta c n gin ho ct m t phng php, cn thc t cn
tnh n vng cng rt n gin m thi. Ri ta to m hnh vi cc thit lp tham kho
minh ho di:
Ta c kt qu l dy ai 3D, nhng cha c kh nng gi nguyn chiu di khi
thay i ng knh cc pulley. lm c iu ny, taEdit Sketchri ly thm cc kch
thc chiu di cung tip xc vi ai v khong cch trc. Nhng kch thc ly thm,
khi m hnh hon ton c xc nh, s c mu xm v ch c gi tr tham kho, chng
khng iu khin c m hnh.By gi ta s rng buc cc kch thc chiu di dy ai,
gi s ta mun chiu di dy ai bng 1600mm. Hin nhin ta c cng thc chiu di
cc cung p pulley cng 2 chiu di nhnh ai thng bng 1600. Ta ly cng
cEquationt trnh nToolra:Nhn ntAdd to cng thc. HpAdd Equationm ra,
ta lm nh sau:
1. Click kch thc400, tn kch thc ny t nhy vo hp thoi.2. Nhn nt
bng =trn hp thoi (nu cha quen th khng nn nhn nt trn bn phm m sai c
php!).3. Nhn nt m ngoc n ( (cng vn dng nt trn hp thoi).4. Nhn cc nt
tng ng c1600.5. Click du tr -.6. Click kch thc chiu di cung th nht
trn vng ho.7. Click du tr - ln na.8. Click kch thc chiu di cung th
hai trn vng ho.9. Nhn nt ng ngoc n )10. Nhn nt chia /.11. Nhn
nt2.Bn so snh vi minh ho di:
Nu thy tng t nh vy l c (tn cc kch thc ca bn c th khc, do th th
ly kch thc khng ging nh minh ho, nhng khng sao c, min l bn cht ca
cng thc phi ng nh trnh by bn trn).Sau nhnOKhai ln ng cc hp thoi li.
Bn thy nh sau:
Lu rng cc gi tr chiu di nhnh ai v khong cch cc trc by gi khc
trc, do rng buc ca cng thc bt chiu di dy ai bng 1600mm. Bn cng thy
rng kch thc chiu di nhnh ai thng c k hiusigma , cho bit rng n b iu
khin bi cng thc nu trn. V th nn mc d n c mu en (kch thc iu khin)
nhng chnh n cng b iu khin, bn khng th tu tin thay i gi tr ca n c
na. Th l ch cn c ng knh cc pulley c th thay i c m thi.By gi, bn th
thay i gi tr ng knh cc pulley m xem, sau khiRebuilt, bn s thy tt c
cc kch thc cn li u thay i, km theo khong cch trc thay i, sao cho
chiu di dy ai vn lun bng 1600. Tt nhin l nu bn g mt gi tr ng knh qu
ln th bi ton s v nghim!
Trnh by v din gii th di nh vy, nhng lm rt nhanh chng v n
gin!Design TableC mt tnh nng rt th v trong SW, l s dng bng thit
kDesign Table, m bn cht l bng tnhExcelc lin kt vi tng file thit k c
th. By gi th n lt cc kch thc m hnh li c iu khin bi bng tnh v nh vy,
ta c th tnh ton cc kch thc trong bng tnh, vi y cc cng thc t n gin n
phc tp, c lu cn thn. Kt qu l ta c mt phng php tnh ton v qun l cc
kch thc m hnh rt hiu qu. i vi nhng m hnh m cc kch thc l kt qu nhng
tnh ton phc tp, phng php ny cng t r u th. Nu m hnh cn thit k li c
nhiu quy cch khc nhau (kiu nh cc chi tit tiu chun) th r rng y l k
thut thit k rt u vit. minh ha cho phng php thit k bng Excel, ti xin
lm mt v d sau:THIT K A XCH LOI XCH NG CON LNNi chung, tnh ton a xch
kh phc tp v vi mi quy chun xch ng con ln khc nhau v/hoc s rng khc
nhau th a xch cng khc nhau. Ta c th p dng bng Excel thit k a xch,
ri khi cn c a xch cho loi xch no, s rng bao nhiu l gn nh ngay lp
tc, ta hon thnh thit k t mt file c sn sau khi np vi d kin.Trong v d
ny, ta thit k a xch 14 rng cho xch ng con ln loi bc xch 1 inch.u
tin, trn mtTop Plane, ta v3 ng trn ng tm ti gc ta , ly cc kch thc
ng knh ca chng ln lt l80, 100v120mm biu din ng knh trong, ng knh
vng chia v ng knh ngoi cho a xch. D nhin cc gi tr ny l ngu nhin, lt
na ta s bt chng phi tun theo cc gi tr c tnh ton trong bng.
d nhn bit cc kch thc ny trong bng tnh, ta t tn cho chng theo cc
k hiu quen thuc. Ta chn kch thc ng knh 100 (l kch thc ng chiadc),
click chut phi v chnProperties. Trong hp thoi ny, i tn ca kch thc
ti trngNamethnhdcriOK.
Tng t, ta i tn cc kch thc cn li thnhDevDi, tng ng vi ng knh ngoi
v trong.Sau , ta thot khi Sketch, trn mn hnh ch cn 3 ng trn ng tm v
khng hin th kch thc. lm cc kch thc xut hin, hy right-click th
mcAnnotations(trong Panel bn tri) ri chnShow Feature Dimensions. a
cc kch thc ny vo bng tnh, ta m bng tnh nh sau: m menuInsert,
chnDesign Table. Ti bng thuc tnh ca Design Table, ta chp nhn cc
thit lp mc nh v nhnOK. Mt ca s Excel xut hin trong vng ha ( bng tnh
khng che khut cc kch thc ca hnh v, trc ta nnPanhnh v xung gc phi di
mn hnh) km theo hp thoiDimensionsyu cu xc nhn cc kch thc s a vo
bng, nhnOK ng hp ny li.Trong bng tnh, B2ang c kch hot, hy
double-click kch thc100trong vng ha, ta s thy tn gi v gi tr kch thc
ny xut hin trong bng tnh ti cc B2vB3. Tip tc lm nh vy vi 2 kch thc
cn li, ta c kt qu nh sau:
Gi tr cc B3, C3 v D3 l gi tr cc kch thc ca m hnh c nhp vo, ta s
tnh chnh xc cc gi tr ny theo cc cng thc c trong gio trnh THIT K CHI
TIT MY quen thuc.Lu :cc tham s ny phi c nhp st nhau, chng phi lin k
v khng c cch qung d ch 1 ct.Ti cc A5, g: Bc xch t,A6:ng kch con ln
D,A7:s rng Z.Ti cc B5, g: 25.4,B6:15.88,B7:14.Lu :khng c phn d liu
ny st vo phn tham s kch thc bn trn, ti thiu phi t cch 1 hng.
Ta c cng thc ng knh chiadc = t / sin ( Pi / Z ),Nh vy, gi tr ca
dc ti B3 c tnh nh sau: Click B3(gi tr 100) v g:=B5/sin(Pi()/B7)(lu
khng c c du cch) riEnter. Ta thy gi tr ca B2 by gi tr
thnh114.147.Ta c cng thc ng knh nhDe = t [ k + 1/tg ( Pi / Z ) ] y
li xut hin thmH s chiu cao rng k, h s ny c gi tr ty thuc vo s rng
ca a xch nh sau:Z < 11, k = 0.58; Z =11~17, k = 0.56; Z =17~35,
k = 0.53 v Z >35 th k = 0.50.Ti A8, g:H s kv B8g nh
sau:=IF(B7
