EP0549955B1 - Method of the fluidised bed type for the shaping of sheet metal - Google Patents
Method of the fluidised bed type for the shaping of sheet metal Download PDFInfo
- Publication number
- EP0549955B1 EP0549955B1 EP92121405A EP92121405A EP0549955B1 EP 0549955 B1 EP0549955 B1 EP 0549955B1 EP 92121405 A EP92121405 A EP 92121405A EP 92121405 A EP92121405 A EP 92121405A EP 0549955 B1 EP0549955 B1 EP 0549955B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- sheet
- punch
- chamber
- fluid
- delivered
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
- B21D22/20—Deep-drawing
- B21D22/205—Hydro-mechanical deep-drawing
Definitions
- the invention relates to a method of the fluidised bed type for the shaping of sheet metal according to the preamble of claim 1, as for example known from JP-A-59056926.
- a method of this type substantially comprises a first stage in which a blank holder is brought into contact with the sheet supported on a forming die provided with a cavity, a second stage in which a pressurised fluid is delivered to the aforesaid cavity beneath the sheet by means of a hydraulic circuit and finally a third stage during which a punch is displaced towards the sheet in order to deform it plastically. Deformation of the sheet takes place in this third stage due to the combined action of the pressures which are generated by the punch on the upper surface of the sheet and by the pressure generated by the aforesaid fluid which acts on the undersurface of the said sheet.
- a method of this type has the disadvantage that relatively complex forms cannot be pressed in a single forming operation, or that they require a plurality of successive shaping operations carried out using different presses and dies.
- the object of this invention is to provide a method of the fluidised bed type for the shaping of sheet metal which does not have the disadvantage which has been described and is therefore capable of carrying out extensive shaping of complex shapes in a single shaping operation.
- a method of the fluidised bed type for the shaping of sheet metal substantially comprising a first stage in which a blank holder is brought into contact with the sheet supported on a shaping die provided with a cavity, a second stage in which a pressurised fluid is delivered to the said cavity below the said sheet by means of a first hydraulic circuit and a third stage during which a punch is displaced towards the said sheet to deform it elastically through the combined effect of the pressures generated by the said punch on the upper surface of the sheet and the pressures generated on the underside of the sheet by the said fluid, characterised in that a second pressurised fluid delivered by a second hydraulic circuit is caused to act on at least one portion of the upper surface of the said sheet so as to balance out the pressures acting against the underside of the said portion while the said punch is moved towards the sheet in the course of the said third stage.
- Figures 1, 2 and 3 show successive configurations of the punch and the sheet in the course of the shaping of the said sheet.
- the method according to the invention substantially comprises a first stage in which a blank holder 1 is brought into contact with the sheet 2 supported on a forming die 3, which is provided with a cavity 4 of suitable shape. During this first stage of the method the blank holder exerts a predetermined pressure against the edges 5 of the sheet so as substantially to provide a hydraulic seal for cavity 4.
- a pressurised fluid is delivered to cavity 4 below undersurface 5 of the sheet through a first hydraulic circuit, which is not illustrated.
- a punch 7 of suitable shape is moved towards cavity 4 in order to deform sheet 2, as is clearly shown in Figure 1.
- the sheet is plastically deformed through the combined action of the pressures which punch 7 exerts against the upper surface 8 of the sheet and the pressures which are generated against the underside 6 of the said sheet by the fluid filling cavity 4. This is obviously held at a predetermined pressure within cavity 4 through suitable means which are not shown.
- a second pressurised fluid which is delivered by a second hydraulic circuit (not shown) is caused to act against the upper surface 9 of at least a portion 10 of sheet 2 in order to balance out the pressures acting on the undersurface 11 of portion 10.
- the second hydraulic fluid is delivered substantially to a chamber 12, which is defined partly by the lower surface of the punch itself, partly by the surface of blank holder 1 and the upper surface 9 of portion 10 of the sheet.
- the second pressurised fluid is delivered to chamber 12 when punch 7 has reached a predetermined point in its stroke and has already begun to deform sheet 2.
- the hydraulic fluid can be fed to a chamber 12 via a conduit 13 provided in blank holder 1.
- This conduit includes a stop valve 14 which can be switched from a first position in which the conduit is in communication with a source (not illustrated) of the second pressurized fluid and a second position in which this allows the said fluid to be discharged, thus maintaining a predetermined fluid pressure within the chamber.
- valve 14 is provided with means to effect a desired resistance to the passage of fluid, so as to maintain the aforesaid predetermined pressure within chamber 12 while punch 7 completes its stroke to deform sheet 2 plastically.
- additional cavity 15 of small size, in e.g. punch 7, as shown in the figures.
- additional chamber 15 is still in communication with conduit 13 and excess pressure in the second hydraulic fluid resulting from closure of conduit 13 by punch 7 is thus avoided.
- the small volume of additional chamber 15 does not have any effect on the geometry and shape characteristics of the semi-finished product obtained by forming the sheet.
Description
- The invention relates to a method of the fluidised bed type for the shaping of sheet metal according to the preamble of claim 1, as for example known from JP-A-59056926.
- As is known, a method of this type substantially comprises a first stage in which a blank holder is brought into contact with the sheet supported on a forming die provided with a cavity, a second stage in which a pressurised fluid is delivered to the aforesaid cavity beneath the sheet by means of a hydraulic circuit and finally a third stage during which a punch is displaced towards the sheet in order to deform it plastically. Deformation of the sheet takes place in this third stage due to the combined action of the pressures which are generated by the punch on the upper surface of the sheet and by the pressure generated by the aforesaid fluid which acts on the undersurface of the said sheet.
- A method of this type has the disadvantage that relatively complex forms cannot be pressed in a single forming operation, or that they require a plurality of successive shaping operations carried out using different presses and dies.
- In fact, when the shape of the punch which is required to effect the forming is such that it does not immediately come into contact with the upper surface of the sheet during the first part of the punches stroke, spaces or chambers whose dimensions decrease as the punch continues its stroke are produced between parts of the outside surfaces of the punch, the inside of the blank holder and the sheet itself. The pressure of the aforesaid fluid acts on the undersurface of the sheet and is not balanced by any other pressure acting on the upper surface, and therefore deformation of the sheet bounding these spaces proceeds in an uncontrolled way and fractures resulting from the high stresses which can be induced in the sheet through the effect of the fluid pressure can easily occur in the course of the piston's stroke.
- In practice shaping has to be performed by means of a large number of passes through different machines and presses in order to avoid the occurrence of this problem.
- The object of this invention is to provide a method of the fluidised bed type for the shaping of sheet metal which does not have the disadvantage which has been described and is therefore capable of carrying out extensive shaping of complex shapes in a single shaping operation.
- This object is accomplished with a method of the fluidised bed type for the shaping of sheet metal substantially comprising a first stage in which a blank holder is brought into contact with the sheet supported on a shaping die provided with a cavity, a second stage in which a pressurised fluid is delivered to the said cavity below the said sheet by means of a first hydraulic circuit and a third stage during which a punch is displaced towards the said sheet to deform it elastically through the combined effect of the pressures generated by the said punch on the upper surface of the sheet and the pressures generated on the underside of the sheet by the said fluid, characterised in that a second pressurised fluid delivered by a second hydraulic circuit is caused to act on at least one portion of the upper surface of the said sheet so as to balance out the pressures acting against the underside of the said portion while the said punch is moved towards the sheet in the course of the said third stage.
- For a better understanding of the stages in the method according to the invention a more detailed description will now be provided with reference to the figures in the appended drawings, in which:
- Figures 1, 2 and 3 show successive configurations of the punch and the sheet in the course of the shaping of the said sheet.
- The method according to the invention substantially comprises a first stage in which a blank holder 1 is brought into contact with the
sheet 2 supported on a formingdie 3, which is provided with acavity 4 of suitable shape. During this first stage of the method the blank holder exerts a predetermined pressure against theedges 5 of the sheet so as substantially to provide a hydraulic seal forcavity 4. - During a second stage of the method a pressurised fluid is delivered to
cavity 4 belowundersurface 5 of the sheet through a first hydraulic circuit, which is not illustrated. In the course of a third stage a punch 7 of suitable shape is moved towardscavity 4 in order to deformsheet 2, as is clearly shown in Figure 1. During this stage the sheet is plastically deformed through the combined action of the pressures which punch 7 exerts against the upper surface 8 of the sheet and the pressures which are generated against theunderside 6 of the said sheet by thefluid filling cavity 4. This is obviously held at a predetermined pressure withincavity 4 through suitable means which are not shown. - In accordance with the invention, a second pressurised fluid which is delivered by a second hydraulic circuit (not shown) is caused to act against the upper surface 9 of at least a
portion 10 ofsheet 2 in order to balance out the pressures acting on theundersurface 11 ofportion 10. - As can be seen clearly from Figure 1, the second hydraulic fluid is delivered substantially to a
chamber 12, which is defined partly by the lower surface of the punch itself, partly by the surface of blank holder 1 and the upper surface 9 ofportion 10 of the sheet. The second pressurised fluid is delivered tochamber 12 when punch 7 has reached a predetermined point in its stroke and has already begun to deformsheet 2. Conveniently the hydraulic fluid can be fed to achamber 12 via aconduit 13 provided in blank holder 1. This conduit includes astop valve 14 which can be switched from a first position in which the conduit is in communication with a source (not illustrated) of the second pressurized fluid and a second position in which this allows the said fluid to be discharged, thus maintaining a predetermined fluid pressure within the chamber. Convenientlyvalve 14 is provided with means to effect a desired resistance to the passage of fluid, so as to maintain the aforesaid predetermined pressure withinchamber 12 while punch 7 completes its stroke todeform sheet 2 plastically. - As punch 7 completes its stroke for further deformation of the sheet, as shown in Figure 2, its deformation increases and it tends to adhere to the surface of the punch. During this deformation of the sheet the pressure of the second hydraulic
fluid filling chamber 12 and the pressure of the first hydraulicfluid filling chamber 4 act on upper surfaces 9 andlower surfaces 11 ofportion 10 of the sheet which has not yet come into contact with the punch respectively. When these pressures are substantially equal,portion 10 is perfectly balanced and therefore no force tends to deform it. As a result the forming deformation produced by punch 7 can continue even though the depth of forming is very great and the shape of the punch is rather complex. - As punch 7 proceeds with its stroke the second fluid is discharged from
chamber 12 throughvalve 14 while the pressure withinchamber 12 is maintained constant through the action ofvalve 14. When punch 7 reaches the end of its forming stroke, as shown in Figure 3, upper surfaces 8 and 9 ofsheet 2 are completely in contact with the corresponding surface of punch 7. In this configuration the second hydraulic fluid which fillschamber 12 has been completely discharged throughconduit 13. - To aid completion of the forming stoke of punch 7 it may be appropriate to provide an
additional cavity 15, of small size, in e.g. punch 7, as shown in the figures. In this way, when punch 7 is at its end stop position shown in Figure 3,additional chamber 15 is still in communication withconduit 13 and excess pressure in the second hydraulic fluid resulting from closure ofconduit 13 by punch 7 is thus avoided. Also the small volume ofadditional chamber 15 does not have any effect on the geometry and shape characteristics of the semi-finished product obtained by forming the sheet. - It is clear that modifications and variants may be made to the method which has been described without going beyond the scope of the invention as defined by the claims
Claims (6)
- A method of the fluidised bed type for forming sheet metal substantially comprising a first stage in which a blank holder (1) is brought into contact with the sheet (2) supported on the forming die (3) provided with a cavity (4), a second stage in which a pressurised fluid is delivered to the said cavity (4) underneath the sheet by means of a first hydraulic circuit and a third stage during which a punch (7) is moved towards the said sheet to deform it plastically through the combined action of the pressures generated by said punch on the uppersurface (8) of the sheet and the pressures generated by the said fluid on the power side (6) of the sheet, characterised in that a second pressurised fluid delivered by a second hydraulic circuit is caused to act on the upper surface (9) of at least one portion (10) of the said sheet (2) so as to balance out the pressures acting on the underside (11) of the said portion while the said punch (7) is moved to deform the said sheet in the course of the said third stage.
- A method according to claim 1, characterised in that the said second hydraulic fluid is delivered to a chamber (12) defined partly by the surfaces of the said punch (7), the said blank holder (1) and the upper surface (9) of the said portion of sheet (10).
- A method according to either of claims 1 or 2, characterised in that the said second pressured fluid is delivered to the said chamber (12) when the said punch (7) has reached a predetermined point in its stroke and is brought into contact with the said sheet (2) and is then gradually discharged from the said chamber during the remaining part of the punches stroke maintaining a predetermined pressure in the chamber while its volume decreases.
- A method according to any one of the foregoing claims, characterised in that the said second hydraulic fluid is delivered to the said chamber (12) through a conduit (13) provided in the said blank holder (1) the course of which includes a stop valve (14) which can be switched from a first position in which the conduit is in communication with a source of the said second pressurised fluid and a second position in which it allows the said second pressurised fluid to be discharged while maintaining a predetermined fluid pressure in the said chamber.
- A method according to any one of the foregoing claims, characterised in that a residual volume which is not zero is maintained in the said chamber when the punch (7) reaches the end of its stroke.
- A method according to claim 5, characterised in that the said residual volume is contained within an additional chamber (15) in communication with the said chamber (12) provided by means of a cavity made in part of the said punch (7) which lies close to the outlet of the said conduit (13) at the end of the forming stroke.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITTO911012 | 1991-12-20 | ||
ITTO911012A IT1250551B (en) | 1991-12-20 | 1991-12-20 | METAL SHEET METAL SHEET PROCESS OF THE FLUID BED TYPE. |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0549955A1 EP0549955A1 (en) | 1993-07-07 |
EP0549955B1 true EP0549955B1 (en) | 1995-11-08 |
Family
ID=11409816
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP92121405A Expired - Lifetime EP0549955B1 (en) | 1991-12-20 | 1992-12-16 | Method of the fluidised bed type for the shaping of sheet metal |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0549955B1 (en) |
JP (1) | JPH05245546A (en) |
BR (1) | BR9204920A (en) |
DE (1) | DE69205959T2 (en) |
IT (1) | IT1250551B (en) |
PL (1) | PL169841B1 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ES2103656B1 (en) * | 1994-10-06 | 1998-05-01 | Idem Construcciones Vascas S L | INJECTED WATER EMBUTITION SYSTEM FOR THE CONFORMATION OF PARTS. |
DE19827614B4 (en) * | 1998-06-20 | 2005-08-25 | Steinhart, Paul, Dipl.-Ing. | Method and device for the production of deep drawn parts |
KR20020076943A (en) * | 2001-03-31 | 2002-10-11 | 현대자동차주식회사 | Dual hydroforming system |
US8534106B2 (en) | 2009-10-19 | 2013-09-17 | Ford Global Technologies, Llc | Hydromechanical drawing process and machine |
PL235400B1 (en) * | 2018-01-29 | 2020-07-13 | Politechnika Warszawska | Method for hydromechanical shaping of thin-walled sections and the die for hydromechanical shaping of thin-walled sections |
CN112893595B (en) * | 2021-01-14 | 2023-06-16 | 山东钢铁集团日照有限公司 | Special die for low-pressure forming of bending axis pipe fitting |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE915327C (en) * | 1951-09-23 | 1954-07-19 | Heinrich Ewald Kranenberg | Device for the production of hollow bodies from sheet metal under hydraulic pressure |
DE951807C (en) * | 1955-04-01 | 1956-11-08 | Heinrich Ewald Kranenberg | Device for the production of hollow bodies from sheet metal under hydraulic pressure |
DE3372937D1 (en) * | 1982-04-20 | 1987-09-17 | Kazuhiko Nakamura | Metal sheet forming process with hydraulic counterpressure |
-
1991
- 1991-12-20 IT ITTO911012A patent/IT1250551B/en active IP Right Grant
-
1992
- 1992-12-02 BR BR9204920A patent/BR9204920A/en not_active IP Right Cessation
- 1992-12-16 EP EP92121405A patent/EP0549955B1/en not_active Expired - Lifetime
- 1992-12-16 DE DE69205959T patent/DE69205959T2/en not_active Expired - Fee Related
- 1992-12-18 JP JP4339091A patent/JPH05245546A/en not_active Withdrawn
- 1992-12-18 PL PL92297058A patent/PL169841B1/en not_active IP Right Cessation
Also Published As
Publication number | Publication date |
---|---|
PL297058A1 (en) | 1993-09-06 |
PL169841B1 (en) | 1996-09-30 |
ITTO911012A0 (en) | 1991-12-20 |
JPH05245546A (en) | 1993-09-24 |
IT1250551B (en) | 1995-04-20 |
BR9204920A (en) | 1994-06-28 |
ITTO911012A1 (en) | 1993-06-21 |
EP0549955A1 (en) | 1993-07-07 |
DE69205959T2 (en) | 1996-07-11 |
DE69205959D1 (en) | 1995-12-14 |
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