CA2548486A1

CA2548486A1 - Forming tool

Info

Publication number: CA2548486A1
Application number: CA002548486A
Authority: CA
Inventors: Kai-Uwe Dudziak
Original assignee: Daimlerchrysler Ag; Kai-Uwe Dudziak
Current assignee: Mercedes Benz Group AG
Priority date: 2003-12-04
Filing date: 2004-11-10
Publication date: 2005-06-16
Also published as: US20080034825A1; DE10356534B3; WO2005053870A1

Abstract

The invention relates to a forming tool (1) comprising an engraving (3) that creates a forming chamber (2), into which a workpiece can be introduced. A
channel (4 to 7) running through the forming tool (1) connects the forming chamber (2) to the tool environment. To achieve a contoured form, which is independent of the channels (4 to 7) that connect the forming chamber (2) to the tool environment, during the forming of the workpiece, the tool (1) comprises a liquid and gas-permeable insert element (8), which is held in a cavity (9) of the tool (1) and together with a peripheral region (10) that faces the forming chamber (2), forms a section of the engraving (3), and the channel (4 to 7) opens into the insert body (8) outside said peripheral region (10).

Description

~

~ CA 02548486 2006-06-O1 r Dai,n~erChrYsler AG
Forming tool The invention relates to a forming die in aCCOx~aanao with the preatttble of patent Cla3,m 1.
R foraging 8~.e of the gener~,a type ie known Prom D1~ 1 Q 1 3 9 13 5 Al . In the C document , the f e~rt~.ug die ha,s a vent lice which i.s foxcned as a passage, ruaa~ within a 8i.e block of the foxmiug die and connects the shaping to ~rpaaa fox~cned by the die cavity to the area surroundfac~
the die. Dur~.ng the ~3haQing of the workpieoe, the nix which ~.s present in the a?aaping ~apaae ~.s dieplaved out of the form~.ug die by the detation of the workpieco.
If a workp~.ecse, in thin case in the form of a hollvar profiled section, is then i.naerted into xhe shaping space of the fonni.ag die and p3.acod under pxesaura, the warkpiece tc~lds 3t~telf to accurately matcah the cavity of the shaping space . Since Che~ vent l~.~pe opens out at the cavity, the opening where ~.t opens out dorms au extsemeiy undesirable mark on the s~oxlSpiece an account of the high ooateect prees~ure with which the workp~.ece is preened onto the -eav~ay to achieve the required eontovur accuracy. The vpe~ing of the line may coca be s0 large thafi the workpiece is proceed i~ato the Li~ao, where ~,t is urides~.rably stamped out, which ~.u=vitablyr Leads to the part, be~.ng scrapped.
~k~e ~.nvez~tian i s based on the ob j act of further developing a fvx~ming die of the generic type a.sz such a ~
3 o war thaC contours wh3.Gh axe uriaf f acted by the arrangement of passages eonnectix~g the shaping space to the area guxroundiag the die are ach~.eved i.a a simple way during the ehapiiag of the workpiece.

' CA 02548486 2006-06-O1

- 2 -Aceord3,ng to the invention, th~.s obj act ~.a achieved by the featuteg of gatent claim 1.
7~1a a result of a liquid-petmeetble and gas-pe~de~ble insert body being ax'ranged in the fotliling die, a ~xripheral region of which forces a pox~t~.on of the cavity, alsd on account of the fluidic ooaneetion of the paosage to this inert body, the op~aing where the passage opens out is vovered, with the result that no ianprint of this opening i,s fox~ned on the workplace ~ah~n

3.t is bG~.xig pressed onto the cavity by tbs forming process, ire parCtculax in the. calibxation phase.
Therefore, the ct~ntours of the v~orkpiece remain uaafteoted during shaping. Si~ace the insert body !.s 2~ pexmeable to liquid and gas, thB Euaction of the passage, namely that of discharging and ii! ap?2~rixte else supplying lic~,uid or a gam, for example ai.r. ins Completely r~taiued. An insert body of this type is sidle to produce and can readily be installed in the die after the recess intend~d for it ha~3 been fo~id.
when a certain state of wear has been reached, the insert body can be exahatzged with little diffiaul.ty u~ir~.g suitable securing mesas , Moreover, the ~,nv~tiou obviates the prob7.em of predeter~uj.ning the eorxect Z~ position for forming the passage, since the insert body means that the raedia which axe to be disehargdd fin the cavity are captured over a certait~ area rather than iu punatfform fashion and can pass through the insert body vi~'tually unimpeded until they reach th.e open~,rag of the passage, wh3.ah s that accurate pos~.t~.on3ng of the passage is no loagcr r~ecassary; the passage carp noW open out at any desired position of the 3,usext body, tri a part~.cutarly preferred reEinemeat of the iaventiox~
as described in claim 2, the iz~aGrt body coasiats of a porous ainta~red metal. This iz~ particular ensures that the iz~sart body is able to withstand, the contact ~

' - 3 -pressures re~tu7.t3,ng from the deformation without berg damaged. The pvros~ity is effected by sim~pls pores and ' u~icropast~agem through which liquids and gastea can penetrate.
zn a further preferred configuration og the invention according to claim 3, the ~.nsezt body is an ultrafius :sieve or a diaphragm. If sin ultrafine sieve ig used, it should be eneu~ed that the mesh is deeigncd to b1 as 3.0 rigid and du~rab~.G as possible and the mesh size ~.a kept as sma..ll as posasib~.e, so that on the oue hand the contact preea~uxea can be absorbed and ou the othex baud ari it~pxirit of the meshes on the v~~rkp~.ece is prevented.
Tf s diaphragm is selected, the diaphrsgcg shauld ~.ikewiee be designed to be rigid iri order in this wsy to Cope with the contact pressures. of eourge, the diaphragm must be des~.gaed in such a Way ae to be permeab~.e to liguids and ga,se~s. In addit~.ou to casiplete permeability in this respect, ee~tipera~eabili.ty of the diaphragm is also eoncefvable. Ultrafine si~wes and dietph7~agmS are 3,nexpeusive, very s~.mple to produce and particular7.y simple to apply to the die. Ire thi.s case, it ~,a also possible for existing foratixlg dies to be retxofi.tted with an i.~xsext body of this types with only ~ 5 a very Small am4unt of ef fort .
sn a further particularly preferred configuration of the form~.ng din according to the iaventiat. as described in claim 4, tl~e form~.ng die is a hydroforming die, in which case the workpieee is foamed by a peripher$lly continuous hollow pxofi~.ed section. zf the terming die ie used as a hydrogoxming die. -th.e coaf~.guration of the form:fng die in accordance with the invention is highly advantageous, since it is known that is the hydrotorm3.ng process extremely h~.gh pressuxeS are exexted on the ho7,lowr prof3,J.ed section, vrthich likewise lea4s to immense contact pressures of Ghe hollow profiled section aga~.nst the die cavity. Sinv~ as a

- 4 -result the shape of the cavity is highly accurately rtpxnduced or: the hollow pmf,iled section, the yvay in ' wl'~iah the i.nvex~tf on prevents imp=ints of the opeuiagg of passages cor~neated to the shaping space is highly ittportant . Ass a result, the outer Comtour of the hollow profiled aectiau, which is of toieranoe~fxee and highly accurate configuration as a result of the hydxoformiag process, im retai~aed without it being necessary to dispense with the supply or xemowal of liquids or gs,Aes from the shaping s~pave or into the shaping space.
Ttie invention is explained in more detail below on the basis of an exet~lary embod3meat illustrated in the araw~.ng, is which the figure, is the toxin of a latex~l lougitud~.na1 section, shows a forming die according to the invention with ~,naest bodies arranged att the shaping apace.
xhe figure illustrates a hydroforming die formed ag forming d~.e ~,, whioh has a cavity 3 fortn~i,~ a shaping space, into which a vrorkpiece (in this case a hollow prof~.led sectiot~f is introduced. The forming die. i taaay~
also be a deep-drawing die. A plurality of pas~sagas 4,

5, 6 arid ~, which eosZnect the shaping space 2 to the area surs~ouading the die, hazre beerz Imachinad into the forming die, Ths pa~aeagea a to ~ are used to supply easd/or discharge lubrivaat to the hollo~o profiled section whi.ah has beau introduced into the foxmi~ag d~.e I, in order to xeduCa the friction between. the hollow progiled sect~.ot~ and the cavity 3 during the forming pxocesa. The passages ~ to ~ can a~.eo be used to d~.scharge air aszd pressure- medium. which otherw~.se, on account of being enclosed ~.n the shaping space 2, would hugely impede the forming process. Air and pressurized fluid in the shaping space 2 or~,g~.r~,ate oa the one hatzd from the voXume of air which has not been ex$elXed during closure of the forming die 1 and oa the other hand, with regard to the pressurized f7,uid, ,from tw4 P802588/WO/l pressuxized fluid gxaCtions, namely the preSsuriaed flui4 which flows out after removal of a fully shaped hollow profiled section from the formi~ag die 1 sad the pressurized fluid which undesirably enters the gap S between hvllo~r profiled section axed cavity 3, peBSing ~.atc the shaping apace 2, during tilling of tha hol~.ow profiled section.
A plurality of liquid-permeable and gas-pezmeable 1,0 insert boc9iss 8 are integrated ixi tht ioraaing die l and are each acaodated J.n a x~cess 9 in the die 1 sear to the ghapiug spare. Although the inse~.-t bodies 8 in this case aonarist of a poroum elu,tQred atetal, it ip also possible for them to be foamed by an ultriviirie ~5 sieve er a diaphragm. The peripk~ex~al regioxi to of the insert bodies 8 whioh faces the Shaping spao~ 2 3t~self in. sash cage foams a portion ef the oa~r~.ty 3, ~w~th the resu~.t that there are no discout~.nuit3eg is the pxofile of the cavity 3. The passages 4 to 7 which xvtl tpithin 20 Che tormirig die s opan Out at a reax fide 7.1 of tha respective inaext body 8 outside sa~.d peripheral, region 10. Qty aecourit og the porosity of the iixsert body 8, the air or pressurized fluid Gan penetrate through the pores and/qr micrope~sgages of the insert body 8 l,nto z5 the passages 4 to 7, from whf.eh they are di.aeharged from tte fortnirtg die either thxcugh the force of gravity or by taeans of e~ suitable punk. Therefore, a3x axxd pressux~.~ed f~.u3;d can eaSi~.y be di~sp~.aced by the workplace, Which is moving eves vloeer to they cav~.ty 3, 30 out of the $hap~.ng space 2 isZto the passages ~ to 7 via the lnsext bodiefs 8, without x~n impxiat of the ogeni,ag of the passages 4 to 7 being fortaed after the wo_rkpiece camas into contact ~rith the ca~ri.t~r 3.
35 Furthermore, it is also aonceivahXe to use an insert body 8 which includes relatively large parts of the die aaviCy 3 az~d in this case comprit~es a plurality of regions o~ the Cavity 3 which are prone to iaaluaions psozsse/wo/~.
-s-of media and therefore require dievhatrge of air and pressurised fluid. rt is is~ th~.s case suffidi~nt for only a single passage to be conneotad to this elongntc invert body s. since on account of the displacempat pressure originating from the workpi.ece which i.s being shaped, the air a~ld the pressuri2ed fluid can e~lso penetrate through lateral, oblique and/or labyriath-like micropassages and pores in the ~.nsert body 8 in order to enter the passage 4, s, 6 or 7. As ~ a resu~.t, there is rio rieeci for aadura0.te positioning of Che passage 4, 5, 6 or 7, which leads to considexabl.e simpligication of the design of the die s, end tkte production of the passage can be automated during manufacture of the die ~. , It is in this case pos~sib~.e to select a loaatior~ wh~.eh is the t~tost appropriate both for the disahaxge of the media and for the desig~a of the die.
Furthermore, it is cozwei.vable for the hydroforcn3.ng die 1 to be ccniigu~red for the widening o! plates, in which case the workpiece is formed by two prat~s on tap of one another, which are vlataped ia~ the forming die 1.
between its upper and lower d~.e blocks. A tZuidia 3ntErnal high pressure is gcneratea between the p~.ate~e by means of a lance-like ~alunger which ig assigned to the fortnix~g die 1, has at least one axial. pres$uri~aed f~.uid pafssage inside it and is inaexted between the plates, with the result that these plates are expanded to form a hollow profiled section.

Claims

1. A forming die having a cavity which forms a shaping space and into which a workpiece can be introduced, and having a passage which runs within the die and connects the shaping space to the axes surrounding the die, characterized in that the die (1) contains a liquid-permeable and gas-permeable insert body (8) , which is held in a recess (9) of the die (1) near to the shaping space and by means of a peripheral region (10) facing the shaping space (2) forms a section of the cavity (3). and in that the passage (4-7) opens out at the insert body (8) outside this peripheral region (10).

The forming die as claimed in claim 1, characterized in that the insert body (8) consists of a porous sintered metal.

3. The forming die as claimed in claim 1, characterized in that the insert body (8) is an ultrafine sieve or a diaphragm.

4. The forming die as claimed in one of claims 1 to 3 , characterized in that the forming die (1) is a hydroforming die, and in that the workpiece is formed by a peripherally continuous hollow profiled section.

5. The forming die as claimed in one of claims 1 to 3, characterized in that the forming die (1) is a hydroforming die, and in that the workpiece is formed by two plates resting on top of one another, which can be clamped in the forming die (1) between an upper die block and a lower die block and between which a fluidic internal high pressure can be generated by means of a lance-like plunger which is assigned to the forming die (1) and is introduced between the plates.