CA2539417A1 - Method for the production of a peripherally closed hollow profile section - Google Patents
Method for the production of a peripherally closed hollow profile section Download PDFInfo
- Publication number
- CA2539417A1 CA2539417A1 CA002539417A CA2539417A CA2539417A1 CA 2539417 A1 CA2539417 A1 CA 2539417A1 CA 002539417 A CA002539417 A CA 002539417A CA 2539417 A CA2539417 A CA 2539417A CA 2539417 A1 CA2539417 A1 CA 2539417A1
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- Prior art keywords
- hollow profile
- profile section
- blank
- forming
- cavity
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- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 18
- 239000000463 material Substances 0.000 claims abstract description 15
- 230000002093 peripheral effect Effects 0.000 claims abstract description 12
- 238000003825 pressing Methods 0.000 claims abstract description 10
- 238000007373 indentation Methods 0.000 claims abstract description 8
- 239000012530 fluid Substances 0.000 claims description 7
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 230000009172 bursting Effects 0.000 description 3
- 239000011324 bead Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- 238000000137 annealing Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
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
- B21D22/02—Stamping using rigid devices or tools
- B21D22/06—Stamping using rigid devices or tools having relatively-movable die parts
-
- 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
- B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
- B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
- B21D26/033—Deforming tubular bodies
- B21D26/047—Mould construction
-
- 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
- B21D35/00—Combined processes according to or processes combined with methods covered by groups B21D1/00 - B21D31/00
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49805—Shaping by direct application of fluent pressure
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Shaping Metal By Deep-Drawing, Or The Like (AREA)
Abstract
The invention relates to a method for the production of a peripherally closed hollow profile section (2) by means of a fluidic, inner high pressure. A
hollow profile blank (7) is inserted into a cavity (10,12) of an inner, high pressure forming tool (5) and is then pressed mechanically into an intermediate form corresponding to the final form of the hollow profile (2).
The intermediate form (11) of the blank (7) is expanded into the final form of the hollow profile section (2) by the inner, high pressure when the tool (5) is closed. In order to enable procedurally secure production of a pre-profilable hollow profile section (2) in a relatively simple manner, the blank (7) which is used is overdimensioned with regard to the peripheral length thereof in relation to the peripheral length of the cavity of the forming tool (10,12). The excess amount of blank material in comparison with the amount of blank material required for full placement of the hollow profile section blank (7) on the cavity (10,12) of the forming tool (5) is pressed inside the blank (17), at the earliest during the pressing process and an indentation is formed.
hollow profile blank (7) is inserted into a cavity (10,12) of an inner, high pressure forming tool (5) and is then pressed mechanically into an intermediate form corresponding to the final form of the hollow profile (2).
The intermediate form (11) of the blank (7) is expanded into the final form of the hollow profile section (2) by the inner, high pressure when the tool (5) is closed. In order to enable procedurally secure production of a pre-profilable hollow profile section (2) in a relatively simple manner, the blank (7) which is used is overdimensioned with regard to the peripheral length thereof in relation to the peripheral length of the cavity of the forming tool (10,12). The excess amount of blank material in comparison with the amount of blank material required for full placement of the hollow profile section blank (7) on the cavity (10,12) of the forming tool (5) is pressed inside the blank (17), at the earliest during the pressing process and an indentation is formed.
Description
DaimlerChrysler AG
Method for the production of a peripherally closed hollow profile section The invention relates to a method for the production of a peripherally closed hollow profile section according to the preamble of patent claim 1.
A generic method is known from US 5,070,717. This describes a method for the production of a peripherally closed hollow profile section, in which a hollow profile section blank, the peripheral length of which corresponds to the peripheral length of a cavity of an internal high pressure forming tool, is inserted into the lower portion of the cavity, said lower portion being formed by a depression of the lower die of the forming tool. Subsequently, the forming tool is closed, the upper die being moved in the direction of the lower die, until they come to bear one against the other and the forming space, delimited by the cavity portions of the upper die and of the lower die, of the forming tool is formed. Since the height of the hollow profile section blank is considerably greater than the height of the forming space, the hollow profile section blank is acted upon and squeezed by the upper die during the closing movement of the forming tool. As the result of squeezing, the hollow profile section blank assumes a preprofiled intermediate form whic-h is enclosed by the forming space of the forming tool. The intermediate form has corrugations and creases, with the result that the wall of the intermediate form is spaced apart sometimes to a greater and sometimes to a lesser extent from the cavity over the periphery of said intermediate form. Finally, a fluidic internal high pressure is generated within the intermediate form of the hollow profile section blank, with the result that the intermediate form is expanded into the final form of
Method for the production of a peripherally closed hollow profile section The invention relates to a method for the production of a peripherally closed hollow profile section according to the preamble of patent claim 1.
A generic method is known from US 5,070,717. This describes a method for the production of a peripherally closed hollow profile section, in which a hollow profile section blank, the peripheral length of which corresponds to the peripheral length of a cavity of an internal high pressure forming tool, is inserted into the lower portion of the cavity, said lower portion being formed by a depression of the lower die of the forming tool. Subsequently, the forming tool is closed, the upper die being moved in the direction of the lower die, until they come to bear one against the other and the forming space, delimited by the cavity portions of the upper die and of the lower die, of the forming tool is formed. Since the height of the hollow profile section blank is considerably greater than the height of the forming space, the hollow profile section blank is acted upon and squeezed by the upper die during the closing movement of the forming tool. As the result of squeezing, the hollow profile section blank assumes a preprofiled intermediate form whic-h is enclosed by the forming space of the forming tool. The intermediate form has corrugations and creases, with the result that the wall of the intermediate form is spaced apart sometimes to a greater and sometimes to a lesser extent from the cavity over the periphery of said intermediate form. Finally, a fluidic internal high pressure is generated within the intermediate form of the hollow profile section blank, with the result that the intermediate form is expanded into the final form of
- 2 -the hollow profile section. It is often such, however, that the intermediate form of the hollow profile section blank is spaced apart from the cavity to an extent such that the expandability of the hollow profile section blank is not sufficient, during the subsequent expansion by means of fluidic internal high pressure, for the latter to come to bear completely against the cavity of the forming tool and therefore to assume the final form of the hollow profile section. In this case, at these points, cracks arise which lead to a bursting of the blank during the expansion of the hollow profile section blank by means of internal high pressure. This is the case particularly, at points on the blank at which very high internal stresses are formed in the material during the squeezing operation as a result of strain-hardening processes. In order to counteract this unreliability in the forming process, the squeezed hollow profile section blank can, as is known, be formed in a plurality of forming steps by intermediate annealing. This, in turn, is particularly complicated and prolongs the production time of the desired hollow profile section, and therefore, on account of the costs also incurred in this case, there is no suitability for large series production.
The object on which the invention is based is to develop a generic method to the effect that the production of a hollow profile section to be preprofiled becomes possible in a relatively simple way and with a high degree of process reliability.
The object is achieved, according to the invention, by means of the features of patent claim 1.
The invention is based on the idea of as far as possible completely filling the forming space even during the pressing operation, that is to say the P031892/w0/1
The object on which the invention is based is to develop a generic method to the effect that the production of a hollow profile section to be preprofiled becomes possible in a relatively simple way and with a high degree of process reliability.
The object is achieved, according to the invention, by means of the features of patent claim 1.
The invention is based on the idea of as far as possible completely filling the forming space even during the pressing operation, that is to say the P031892/w0/1
- 3 -preprofiling operation. For this purpose, departing entirely from the prior art, a tubular hollow profile section blank of, for example, circular-cylindrical or oval cross section is used, the peripheral length of which possesses oversize, as compared with the peripheral length of the forming tool cavity. As a result, if only because of this, the unformed hollow profile section blank inserted into the tool cavity fills more of the forming space of the forming tool than has hitherto been the case. Consequently, at the same time, more blank material which can be formed in the forming space is also available. As a result of the pressing operation, the overdimensioned hollow profile section blank is pressed even into those regions of the forming space into which a normally dimensioned hollow profile section blank cannot penetrate. In this case, it proves beneficial if, during pressing, the hollow profile section blank can spread out freely into the regions where access is difficult. This may be brought about, on the one hand, by a corresponding configuration of the cavity of the forming tool or, on the other hand, by moveable tool parts of the forming tool which with a surface form part of the cavity and are arranged outside the region of spread of the hollow profile section blank during the pressing operation. On account of the overlength of the hollow profile section blank in the peripheral direction, as compared with the peripheral length of the forming space, the hollow profile section blank, even in the pressed state, has a larger cross section than the forming space. In order to obtain the desired configuration of the hollow profile section, therefore, the hollow profile section blank must be adapted in terms of its cross section or of its cross-sectional size to the cross section of the forming space. This takes place by the excess hollow profile section blank material being pushed into the blank interior, an indentation being formed in the
- 4 -hollow profile section blank. Expediently, for this purpose, the pushing-in operation takes place at the earliest during the pressing operation. The preprofiled intermediate form of the hollow profile section blank then lies in the forming space such that only low degrees of forming are required in order to bring the hollow profile section blank completely to bear against the forming tool cavity by means of internal high pressure. Cracks which may lead to the bursting of the hollow profile section blank can consequently no longer occur. The method according to the invention consequently exhibits a solution, to be implemented relatively simply, as to how a squeezed and thus preprofiled hollow profile section blank can be formed into the final form of the hollow profile section with a high degree of process reliability. In summary, for this purpose, in addition to the normal sequence of the production method, only the pushing-in operation is required, which displaces the excess hollow profile section b_Lank material into the interior of the hollow profile section blank, which, if appropriate, does not even signify a longer production time of the hollow profile section if the pushing-in process takes place during the squeezing operation, that is to say during the preprofiling of the hollow profile section blank.
The provision of an overdimensioned hollow profile section blank does not entail any additional outlay. On the contrary, it is conceivable that, in the production of hollow profile sections of small diameter, the hollow profile section blanks, because of their overdimensioning, can be produced more simply and with a more uniform wall thickness profile, and this can certainly be conducive to the high degree of process reliability of the entire production process of the hollow profile section.
The provision of an overdimensioned hollow profile section blank does not entail any additional outlay. On the contrary, it is conceivable that, in the production of hollow profile sections of small diameter, the hollow profile section blanks, because of their overdimensioning, can be produced more simply and with a more uniform wall thickness profile, and this can certainly be conducive to the high degree of process reliability of the entire production process of the hollow profile section.
- 5 -In a preferred development of the invention, as claimed in claim 2, the pushing-in operation after the formation of the intermediate form takes place by means of a moveable forming element which remains in the push-in position during the internal high pressure forming. On account of the movability of the forming element, in a retracted position of the forming element the hollow profile section blank can spread out freely in the direction of the forming element during the squeezing and pressing operation, so that said hollow profile section blank occupies the forming space of the forming tool virtually completely in this region. The forming element may be a moveable part of the forming tool, but, for the flexibility of the forming tool in the production of different hollow profile sections, it is advantageous to provide the forming element as a separate component, for example, as an exchangeable slide or ram which can, as required, be removed from the forming tool or be placed into the latter at a suitable point. For this purpose, at said suitable points, removable die segments of the forming tool are to be provided, which, if required, are replaced by the ram or slide. After the pushing-in operation, the forming element remains in its push-in position in a simple way and forms a part of the cavity. By the push in surface of the forming element being designed specially as a cavity, a complicated moving of the forming element out of the forming tool and subsequent moving-in of a cavity part of the forming tool which replaces the forming element may be dispensed with.
In a further preferred embodiment of the invention, as claimed in claim 3, the hollow profile section blank is filled with pressure fluid before the pushing-in operation. By virtue of this measure which affords an internal support for the hollow profile section blank, the occurrence of creases during the pressing operation P031892/wo/1
In a further preferred embodiment of the invention, as claimed in claim 3, the hollow profile section blank is filled with pressure fluid before the pushing-in operation. By virtue of this measure which affords an internal support for the hollow profile section blank, the occurrence of creases during the pressing operation P031892/wo/1
- 6 -is counteracted, thus further increasing the degree of process reliability.
The invention is explained in more detail below by means the of an exemplary embodiment illustrated in draw ings in which:
fig. 1 shows, in a cross-sectional illustration, an opening position of a device carrying out the method according to the invention, having an internal high pressure forming tool and a forming element, with a hollow profile sect ion blank inserted into the forming tool, fig. 2 shows, in a cross-sectional illustration, the forming tool from figure 1 in the clo sed position, with a pressed hollow profile sect ion blank, fig. 3 shows, in a cross-sectional illustration, the closed forming tool from figure 1, with a hollow profile section blank pushed in by the forming element, after expansion by means of fluidic internal high pressure.
Figure 1 illustrates a device 1 for the production of a peripherally closed hollow profile section 2 by means of fluidic internal high pressure, said device containing an internal high pressure forming tool 5 formed from an upper die 3 and from a lower die 4, and also a forming element 6. Although the forming element 6 may be part of the lower die 4 or of the upper die 3, here, however, it is a separate component which is driven mechanically, pneumatically or hydraulically at the rear. By means of the drive, the forming element 6 can be moved back and forth with respect to the hollow profile section blank 7, the forming element 6 being displaceable in guides which are arranged on the top side 8 of the lower die 4 and on the under side 9 of the upper die 3.
For the sequence of the production method, according to figure 1, a hollow profile section blank 7 is inserted into the cavity 10 of the lower die 4 in the open state of the internal high pressure forming tool 5.
Thereafter, the forming tool 5 is closed, the upper die 3 being lowered onto the lower die 4. In this phase, the forming element 6 remains in its retracted position of non-use. In the closed position according to figure 2, the forming element 6 is framed by the upper die 3 and the lower die 4. During the closing movement, the upper die 3 acts upon the hitherto still unformed hollow profile section blank 7 and squeezes its form having a circular-cylindrical cross section into an intermediate form 11 which is roughly approximate to the form of the forming space 13, formed by the cavity 10 of the lower die 4 and the cavity 12 of the upper die 3, of the forming tool 5 and, consequently, to the final form of the hollow profile section 2. Since the peripheral length of the hollow profile section blank 7 is markedly greater than the peripheral length of the forming space 13, the intermediate form 11 of the hollow profile section blank 7 projects beyond the forming space 13 and extends toward the forming element 6. The in this case overshot limit 14 of the forming space 13 is illustrated by dashes. After the conclusion of the squeezing and pressing operation, that is to say in the closed position of the forming tool 5, the intermediate form 11 of the hollow profile section blank 7 bears virtually completely against the cavities 10 and 12 of the lower die 4 and of the upper die 3. In the present exemplary embodiment, there is only one region 15 of the intermediate form 11 which is spaced apart, but only just, from the cavities 10 and 12.
Then, after the forming element 6 has been moved onto the intermediate form 11 of the hollow profile section blank 7, the excess hollow profile section blank _ g _ material which has overshot the limit 14 of the forming space 13 is pushed in by said forming element, as we may gather from figure 3. For this purpose, the forming element 6 has a forming bead 16, by means of which it displaces the excess hollow profile section blank material beyond the limit 14 back into the blank interior 17, at the same time forming an indentation 18 on the intermediate form 11. Above and below the forming bead 16, the surfaces of that side of the forming element 6 which faces the intermediate form 11 are configured in such a way that they form the lateral walls of the forming space 13 and consequently the lateral cavity 19 of the latter. During said pushing-in operation, the intermediate form 11 of the hollow profile section blank 7 may already be filled with pressure fluid, in order to obtain an internal support which is to prevent unwanted creases and collapses during the pushing-in operation. On the other hand, the intermediate form 11 of the hollow profile section blank 7 is then sealed off at each of the two ends by means of an axial ram and is filled with pressure fluid via axial ducts which run within the axial ram. The axial ram has connected to it a fluid high pressure generation system, via which the pressure fluid within the blank interior 7 is pressurized. While the forming element 6 remains in its push-in position, the intermediate form 11 of the hollow profile section blank 7 expands under the internal high pressure generated and, even in the region 15, comes to bear, true to contour, against the cavities 10 and 12 of the forming tool 5, so as to produce the final form of the hollow profile section 2. Finally, the pressure fluid is depressurized again and the forming element 6 is moved out of its push-in position back into its position of non-use. The forming tool 5 is then opened and the ready-formed hollow profile section 2 is extracted from this.
Moreover, the method is to be carried out such and the forming separation of the two dies 3 and 4 is to be provided such that the generation of the indentation 18 takes place at as favorable a point as possible for the hollow profile section 2 in light of its intended use.
In this case, the generated indentation 18, by means of which construction space is saved in the hollow profile section 2, may serve for the free movement and/or for the leadthrough of other assemblies and components and may be used as a receptacle and/or tie-up for other components. Furthermore, the indentation 18 may also be used as a bolster which appreciably increases the rigidity of the hollow profile section 2. If appropriate, the indentation 18, as a decorative fold, may also fulfill special visual requirements. Overall, by means of the method according to the invention, hollow profile section components with highly complex geometries can be produced with a degree of process reliability.
The idea according to the invention may also be adopted in the following scenario. Complex components, in particular frame structure components of motor vehicles, often have cross sections of completely different size over their longitudinal extent according to the installation conditions and the respective local mechanical and/or visual requirements. To produce them from a tubular blank in an internal high pressure forming tool, there is, even after a preprofiling operation, a different degree of forming for each cross section. Conventionally, a hollow profile section blank is selected, the diameter of which corresponds to that of the smallest cross section of the tool cavity adapted exactly to the desired form of the component to be produced. At specific points on the blank, the degrees of forming are such that the expandability of the blank is no longer sufficient to produce the desired form of the component with a high degree of process reliability. Instead, the blank fails by splitting or as a result of bursting phenomena. To ensure process reliability in the production of the component, then, the selected initial cross section for the hollow profile section blank on the basis of the invention, as compared with the prior art, is in any event larger than the minimum cavity cross section and advantageously corresponds to a cross section which is averaged over the multiplicity of cavity cross sections along the longitudinal extent of the cavity or for the cross sections of the future component to be formed, so that the forming space formed by the cavity is filled to a considerably greater extent. In this case, the blank is squeezed at points of small cross section, in which case squeezing would impede the operation of closing the forming tool on account of the excess blank material. Owing to the arrangement of the slides and to their retracted position, then, the blank material can be displaced into regions of the forming tool in which the material would otherwise have prevented the closing of the tool. In order, however, to maintain the predetermined external dimensions and not to encroach upon the available construction space of the component, the excess material is pushed back into the interior of the hollow profile section blank by means of the forming element or forming elements.
The invention is explained in more detail below by means the of an exemplary embodiment illustrated in draw ings in which:
fig. 1 shows, in a cross-sectional illustration, an opening position of a device carrying out the method according to the invention, having an internal high pressure forming tool and a forming element, with a hollow profile sect ion blank inserted into the forming tool, fig. 2 shows, in a cross-sectional illustration, the forming tool from figure 1 in the clo sed position, with a pressed hollow profile sect ion blank, fig. 3 shows, in a cross-sectional illustration, the closed forming tool from figure 1, with a hollow profile section blank pushed in by the forming element, after expansion by means of fluidic internal high pressure.
Figure 1 illustrates a device 1 for the production of a peripherally closed hollow profile section 2 by means of fluidic internal high pressure, said device containing an internal high pressure forming tool 5 formed from an upper die 3 and from a lower die 4, and also a forming element 6. Although the forming element 6 may be part of the lower die 4 or of the upper die 3, here, however, it is a separate component which is driven mechanically, pneumatically or hydraulically at the rear. By means of the drive, the forming element 6 can be moved back and forth with respect to the hollow profile section blank 7, the forming element 6 being displaceable in guides which are arranged on the top side 8 of the lower die 4 and on the under side 9 of the upper die 3.
For the sequence of the production method, according to figure 1, a hollow profile section blank 7 is inserted into the cavity 10 of the lower die 4 in the open state of the internal high pressure forming tool 5.
Thereafter, the forming tool 5 is closed, the upper die 3 being lowered onto the lower die 4. In this phase, the forming element 6 remains in its retracted position of non-use. In the closed position according to figure 2, the forming element 6 is framed by the upper die 3 and the lower die 4. During the closing movement, the upper die 3 acts upon the hitherto still unformed hollow profile section blank 7 and squeezes its form having a circular-cylindrical cross section into an intermediate form 11 which is roughly approximate to the form of the forming space 13, formed by the cavity 10 of the lower die 4 and the cavity 12 of the upper die 3, of the forming tool 5 and, consequently, to the final form of the hollow profile section 2. Since the peripheral length of the hollow profile section blank 7 is markedly greater than the peripheral length of the forming space 13, the intermediate form 11 of the hollow profile section blank 7 projects beyond the forming space 13 and extends toward the forming element 6. The in this case overshot limit 14 of the forming space 13 is illustrated by dashes. After the conclusion of the squeezing and pressing operation, that is to say in the closed position of the forming tool 5, the intermediate form 11 of the hollow profile section blank 7 bears virtually completely against the cavities 10 and 12 of the lower die 4 and of the upper die 3. In the present exemplary embodiment, there is only one region 15 of the intermediate form 11 which is spaced apart, but only just, from the cavities 10 and 12.
Then, after the forming element 6 has been moved onto the intermediate form 11 of the hollow profile section blank 7, the excess hollow profile section blank _ g _ material which has overshot the limit 14 of the forming space 13 is pushed in by said forming element, as we may gather from figure 3. For this purpose, the forming element 6 has a forming bead 16, by means of which it displaces the excess hollow profile section blank material beyond the limit 14 back into the blank interior 17, at the same time forming an indentation 18 on the intermediate form 11. Above and below the forming bead 16, the surfaces of that side of the forming element 6 which faces the intermediate form 11 are configured in such a way that they form the lateral walls of the forming space 13 and consequently the lateral cavity 19 of the latter. During said pushing-in operation, the intermediate form 11 of the hollow profile section blank 7 may already be filled with pressure fluid, in order to obtain an internal support which is to prevent unwanted creases and collapses during the pushing-in operation. On the other hand, the intermediate form 11 of the hollow profile section blank 7 is then sealed off at each of the two ends by means of an axial ram and is filled with pressure fluid via axial ducts which run within the axial ram. The axial ram has connected to it a fluid high pressure generation system, via which the pressure fluid within the blank interior 7 is pressurized. While the forming element 6 remains in its push-in position, the intermediate form 11 of the hollow profile section blank 7 expands under the internal high pressure generated and, even in the region 15, comes to bear, true to contour, against the cavities 10 and 12 of the forming tool 5, so as to produce the final form of the hollow profile section 2. Finally, the pressure fluid is depressurized again and the forming element 6 is moved out of its push-in position back into its position of non-use. The forming tool 5 is then opened and the ready-formed hollow profile section 2 is extracted from this.
Moreover, the method is to be carried out such and the forming separation of the two dies 3 and 4 is to be provided such that the generation of the indentation 18 takes place at as favorable a point as possible for the hollow profile section 2 in light of its intended use.
In this case, the generated indentation 18, by means of which construction space is saved in the hollow profile section 2, may serve for the free movement and/or for the leadthrough of other assemblies and components and may be used as a receptacle and/or tie-up for other components. Furthermore, the indentation 18 may also be used as a bolster which appreciably increases the rigidity of the hollow profile section 2. If appropriate, the indentation 18, as a decorative fold, may also fulfill special visual requirements. Overall, by means of the method according to the invention, hollow profile section components with highly complex geometries can be produced with a degree of process reliability.
The idea according to the invention may also be adopted in the following scenario. Complex components, in particular frame structure components of motor vehicles, often have cross sections of completely different size over their longitudinal extent according to the installation conditions and the respective local mechanical and/or visual requirements. To produce them from a tubular blank in an internal high pressure forming tool, there is, even after a preprofiling operation, a different degree of forming for each cross section. Conventionally, a hollow profile section blank is selected, the diameter of which corresponds to that of the smallest cross section of the tool cavity adapted exactly to the desired form of the component to be produced. At specific points on the blank, the degrees of forming are such that the expandability of the blank is no longer sufficient to produce the desired form of the component with a high degree of process reliability. Instead, the blank fails by splitting or as a result of bursting phenomena. To ensure process reliability in the production of the component, then, the selected initial cross section for the hollow profile section blank on the basis of the invention, as compared with the prior art, is in any event larger than the minimum cavity cross section and advantageously corresponds to a cross section which is averaged over the multiplicity of cavity cross sections along the longitudinal extent of the cavity or for the cross sections of the future component to be formed, so that the forming space formed by the cavity is filled to a considerably greater extent. In this case, the blank is squeezed at points of small cross section, in which case squeezing would impede the operation of closing the forming tool on account of the excess blank material. Owing to the arrangement of the slides and to their retracted position, then, the blank material can be displaced into regions of the forming tool in which the material would otherwise have prevented the closing of the tool. In order, however, to maintain the predetermined external dimensions and not to encroach upon the available construction space of the component, the excess material is pushed back into the interior of the hollow profile section blank by means of the forming element or forming elements.
Claims (3)
1. A method for the production of a peripherally closed hollow profile section by means of fluidic internal high pressure, a hollow profile section blank being inserted into a cavity of an internal high pressure forming tool, and thereafter being pressed mechanically into an intermediate form approximate to the final form of the hollow profile section, after which, with the tool closed, the intermediate form of the blank is expanded into the final form of the hollow profile section by means of the internal high pressure, characterized in that a hollow profile section blank (7) is used, which, in terms of its peripheral length, possesses oversize with respect to the peripheral length of the forming tool cavity (10, 12), in that the hollow profile section blank (7) is pressed into an intermediate form (11) which, with the blank material which is excess with respect to the blank material required for the hollow profile section blank (7) to come to bear completely against the cavity (10, 12) of the forming tool (5), overshoots the limit (14) of the forming space (13) reproducing the final form of the hollow profile section, and in that the excess blank material is then pushed into the blank interior (17), so as to form an indentation (18), at the earliest during the pressing operation.
2. The method as claimed in claim 1, characterized in that the pressing-in operation takes place after the formation of the intermediate form (11) by means of a moveable forming element (6) which remains in the press-in position during the internal high pressure forming.
11 a
11 a
3. The method as claimed in either one of claims 1 or 2, characterized in that the hollow profile section blank (7) is filled with pressure fluid before the pressing-in operation.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10343135A DE10343135B4 (en) | 2003-09-18 | 2003-09-18 | Method for producing a circumferentially closed hollow profile |
| DE10343135.7 | 2003-09-18 | ||
| PCT/EP2004/008925 WO2005035160A1 (en) | 2003-09-18 | 2004-08-10 | Method for the production of a peripherally closed hollow profile section |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2539417A1 true CA2539417A1 (en) | 2005-04-21 |
Family
ID=34428092
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002539417A Abandoned CA2539417A1 (en) | 2003-09-18 | 2004-08-10 | Method for the production of a peripherally closed hollow profile section |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20070271980A1 (en) |
| EP (1) | EP1663537A1 (en) |
| CA (1) | CA2539417A1 (en) |
| DE (1) | DE10343135B4 (en) |
| WO (1) | WO2005035160A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102005055237B4 (en) * | 2005-11-19 | 2010-08-26 | Daimler Ag | Device for fixing a bearing in a housing |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5070717A (en) * | 1991-01-22 | 1991-12-10 | General Motors Corporation | Method of forming a tubular member with flange |
| DE19530056B4 (en) * | 1995-08-16 | 2004-09-09 | Schuler Hydroforming Gmbh & Co. Kg | Method and device for producing T-shaped or at least one dome-like hollow body |
| US5557961A (en) * | 1995-11-13 | 1996-09-24 | General Motors Corporation | Hydroformed structural member with varied wall thickness |
| PL183949B1 (en) * | 1996-08-26 | 2002-08-30 | Cosma Int Inc | Press-forming die and hydraulic combination press forming method especially for use in production of pipes |
| JP3206505B2 (en) * | 1997-08-06 | 2001-09-10 | 住友金属工業株式会社 | Hydraulic bulge processing method and hydraulic bulge processing apparatus for metal tube |
| DE19813012C2 (en) * | 1998-03-25 | 2002-08-01 | Daimler Chrysler Ag | Process for producing a hollow body from a tubular blank by hydroforming |
| US6415638B1 (en) * | 1999-03-26 | 2002-07-09 | Nissan Motor Co., Ltd. | Method and device for forming tubular work into shaped hollow product by using tubular hydroforming |
| US6209372B1 (en) * | 1999-09-20 | 2001-04-03 | The Budd Company | Internal hydroformed reinforcements |
| US6257035B1 (en) * | 1999-12-15 | 2001-07-10 | Ti Corporate Services Limited | Compressive hydroforming |
-
2003
- 2003-09-18 DE DE10343135A patent/DE10343135B4/en not_active Expired - Fee Related
-
2004
- 2004-08-10 CA CA002539417A patent/CA2539417A1/en not_active Abandoned
- 2004-08-10 EP EP04763945A patent/EP1663537A1/en not_active Withdrawn
- 2004-08-10 WO PCT/EP2004/008925 patent/WO2005035160A1/en not_active Application Discontinuation
- 2004-08-10 US US10/572,317 patent/US20070271980A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP1663537A1 (en) | 2006-06-07 |
| WO2005035160A1 (en) | 2005-04-21 |
| US20070271980A1 (en) | 2007-11-29 |
| DE10343135A1 (en) | 2005-05-12 |
| DE10343135B4 (en) | 2006-02-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |