JP2006528074A - Method for manufacturing a hollow member with a closure cover at the end and jack bracket - Google Patents

Abstract

  The present invention relates to a method of manufacturing a hollow member (6) having a terminal cover (7) and an inflating part (37), and a jack bracket (32) manufactured by the method. An object of the present invention is to manufacture a jack bracket (32) that is easily manufactured by the above-described method and secures a large mechanical load bearing capacity, and at the same time, easily manufactures an expanded hollow member (6) having a cover (7). is there. Said object is achieved by inserting a cap-like cover (7) into a hollow member (6) arranged in a mold (1) which is deformed under high internal pressure. The axial ram (8) is inserted into the end of the cover (7) and the hollow member after closing the deformation mold (1), so that the edge of the cover (7) is radial with the surrounding hollow member (6). The hollow member (6) is then expanded by the high internal pressure.

Description

  The present invention relates to a method of manufacturing a hollow member having a closing cover on an end side, and a jack bracket.

  The prior art described here by patent document 1 discloses a method of manufacturing a hollow shaft end. In this method, the plastic stopper is pushed into the hollow shaft. A hollow shaft together with the plastic stopper is placed in the hydroforming die, after which the axial ram then acts on the end of the hollow shaft in which the plastic stopper is placed. At the same time, hydroforming pressure is generated in the hollow shaft, the effect of which, in combination with the pressure acting in the axial direction of the ram, is to push the walls of the hollow shaft towards the end faces of the plastic stopper. As a result, the plastic stopper is held so as to be frictionally and reliably locked by this compressive force, so that the plastic stopper is anchored in the hollow shaft.

  Furthermore, patent document 2 is disclosing the jack bracket formed from the sheet-metal shell structure. The jack bracket has a mounting area where it is secured to the lower sill area by spot welding. The welded shell structure has an opening at the other end, and a plastic stopper having a recess is fitted into the opening, so that the journal of the jack can be inserted into this recess. The shell structure of the bracket is relatively complicated to manufacture in terms of processing technology and equipment due to the nature of the multi-part structure.

German Patent Invention No. 100 49 048 C1 German Patent Invention No. 195 28 309 C2 Specification

  An object of the present invention is to provide a method for facilitating the manufacture of an expanded hollow member having a closure cover. A further object is to specify a jack bracket that has lower manufacturing costs and ensures high durability against mechanical stresses.

  According to the invention, this object is achieved by the features of claim 1 with respect to the manufacturing method and by the features of claim 12 with respect to the jack bracket.

  Due to the use of an integrally molded peripheral continuous hollow member as the base body for the jack bracket, a high bending strength of the bracket is achieved that can withstand very high mechanical stresses without damage. The hollow member can be ideally matched to the periphery of the bracket by hydroforming, due to the relatively low degree of deformation, which reveals an inflatable portion that is easy to form using hydroforming. As a result of the absence of manufacturing tolerances due to the construction method, it becomes easy to automate the mounting of the bracket to the lower region of the automobile sill. This attachment simply requires the formation of a weld flange that can be manufactured by a relatively simple cutting and bending operation at the corresponding end of the hollow member. The opposite end of the hollow member is closed by a closing cover, to which a jack can be fitted directly or indirectly. Pressing the closure cover in the hydroforming die on which the method according to the invention for joining the closure cover and the hollow member is normally required to press the cover into the hollow member from the outside, Eliminate additional tools such as holding means and press dies. Furthermore, the pressing is performed by the introduction of an axial ram into the hollow member, which is economical in terms of process engineering because it is an essential action that a seal is produced during hydroforming. . Since the hollow member abuts without play between the cavity of the hydroforming die and the cover rim, and a part abuts against the pressure ramp of the internal axial ram, the hollow member is preferably undesired or wrinkled in the pressing area. Without maintaining its contour. Next, the expanding portion is formed by introducing hydroforming pressure into the hollow member. When the cover completely closes the hollow member, hydroforming pressure is guided via the other end of the hollow member. Overall, the equipment requirements for the hydroforming process allow this process to be combined with a single die pressing process, which significantly simplifies the production of an expanded hollow member with a closed cover. . The above need to tightly seal the axial ram against high pressure fluid inside the hollow member results in a high frictional lock between the cover rim and the hollow member and for any intended use onto the hollow member. Involved in the very good retention of the cover.

  In an improvement of the method according to the invention as claimed in claim 2, the cover is loosely fitted into the hollow member outside the forming die. This has the advantage that the closure cover and the hollow member can be preassembled and then placed in the hydroforming die as a single unit for further processing.

  Another advantageous improvement of the invention as claimed in claim 3, which is considered as an alternative to the improvement as claimed in claim 2, is that the closure cover is fed by an axial ram to a hollow member arranged in the forming die. In other words, the pressing performed as the feeding operation is performed. In this case, the closing cover feed is carried out in a single operation with pressing, economically with respect to process engineering. Furthermore, the closure cover is placed in the middle of the axial ram even before it is introduced into the hollow member and is thus arranged in the desired manner.

  Claim 4 shows another advantageous improvement of the invention, in which, before the closure cover is inserted into the hollow member, the cover is designed to have an outer diameter larger than the inner diameter of the hollow member. Due to the specific design with two diameters, the introduction of the cover into the hollow member is a particularly high level of press fit when the axial ram also has a pressure profile. In other cases, the press-fit is not very strong, but it can also be done without using a special configuration of the pressing profile of the axial ram. However, for the indicated diameter, the insertion slope of the cover rim is useful to facilitate the closure cover being introduced into the hollow member.

  In a further advantageous configuration according to the invention as claimed in claim 5, the cover rim is clamped in place with a hollow member by a combined hydroforming pressure at the same time as the axial progression of the axial ram, and the hollow member material Is moved into a space delimited by the closing edge of the cover rim and the opposing shoulder of the axial ram by an advancing action combined with hydroforming pressure. On the one hand, the hydroforming pressure combined with the axial ram pressure creates an inwardly projecting thick section in the hollow member that abuts the cover rim, and on the other hand flows into the space for hydroforming pressure and advancing motion. The hollow member material that engages behind the cover rim. This provides a positive lock between the hollow member and the closure cover, which further increases the holding force between the two components.

  Another advantageous configuration of the invention is presented by claim 6. This relates to the formation of an opening in the cover base and the expansion of the hollow member by pressurized fluid introduced into the hollow member via the passage in the axial ram and the opening in the cover base. Forming an opening in the cover base and providing a flow path for the axial ram provides a very useful multi-function for the axial ram, i.e. the ability to block the supply of pressurized fluid and press the rim of the cover against the hollow member. give. The opening in the cover base subsequently serves as a receiving element for other components after the formation of the hollow member.

  In an advantageous refinement of the method according to claim 6, according to claim 7, a bottle-shaped extension is formed around the opening of the cover base in the cover, in the extension on the end side of the axial ram. A forming projection in the form of a hollow journal is introduced. If the cover formed in this way is already fitted in the hollow member, the bottle-like extension acts as a centering means for the axial ram, which can then be docked to the closure cover without clogging, Its journal-like projections protrude through the opening in the cover base. This further holds the axial ram to the cover—through the cover—to the hollow member. If the closure cover has not yet been loosely held in the hollow member and is only supplied with the axial ram, the cover is easily fitted with the axial ram so that the closure cover is axially As the ram is fed, it is tethered to the axial ram and introduced into the hollow member.

  In another advantageous refinement of the invention as claimed in claim 8, after the hollow member has been expanded, it is guided and integrated in the forming die and engages an axially extending groove of the axial ram. The hollow edge and the closing edge of the cover rim are subjected to the action of sliding, opening towards the end side of the axial ram. The slide in this case prevents the closure cover from being pulled out of the hollow member and pulled out after the axial ram has been withdrawn. The movement of withdrawing the axial ram is not affected by the slide due to the opening groove.

  In a further advantageous configuration of the invention as defined in claim 9, the closing edge of the cover rim is shaped to project radially outward. The tubular collar portion to be formed next forms an axial stopper for the closing cover, and the axial stopper is supported by the closing edge of the hollow member. The cover cannot be pushed into the interior of the hollow member when subjected to a higher axial mechanical load on the pressed assembly.

  Another advantageous configuration of the invention is presented by the content of claim 10. In this case, the cover rim is perforated, and after the cover is pressed against the hollow member, the hollow member material is pushed into the holes formed in the cover rim, respectively, by a ram that is guideably integrated in the forming die. . This forms a local secure locking connection between the hollow member and the cover, while preventing the closing cover from being dragged in the same direction when the axial ram is pulled, while the two axial directions The closure cover is also prevented from being pushed into the interior of the hollow member due to the higher mechanical axial load from.

  In another advantageous development of the method according to the invention as claimed in claim 11, when the axial ram is introduced, the hollow member and the cover are one of the cavities of the forming die that conically expand towards the axial ram. As it is pressed towards the compartment, a contoured surface can be formed that matches the cover rim and the hollow member. In this improvement, the pressed assembly of the hollow member and closure cover is further strengthened. Furthermore, the closing cover is also prevented from being pushed into the hollow member.

  Furthermore, claim 13 provides another advantageous configuration of the jack bracket according to the invention. In this case, the bracket on the cover base has an opening that forms a receiving element for a stopper to which a jack is attached. For precise positioning of the closure cover in the hollow member, part of which is manufactured without manufacturing tolerances due to the adoption of hydroforming, the opening for receiving the stopper is very precisely defined. This allows a lifting platform designed as a jack, which is controlled completely automatically when the vehicle is in the factory, to always be fitted in the correct position of the jack bracket.

  In the following document, the invention will be described in detail on the basis of a number of exemplary embodiments shown in the drawings.

  FIG. 1 shows an open hydroforming die 1 having a top die part 2 and a bottom die part 3 defining a hydroforming space 5 in an internal cavity 4. The hollow member 6, which is made of a light metal or steel and made from a plate that is wound into a drawn tube or tube and then welded with a longitudinal seam, is already arranged in the lower die part 3. The arrangement shown having a forming die 1 and a hollow member 6 also has a closing cover 7 and an axial ram 8, in this case outside the forming die 1 in order to explain the manufacturing method according to the invention. Although spaced apart, they are each placed in a straight line with the hollow member 6 to specify the direction in which they are united. The closing cover 7 has a cup-like structure, and its base 9 is on the side facing the hollow member 6. The cover 7 may be a deep drawn sheet metal part or casting, in particular hot chamber die casting. The axial ram 8 becomes narrower toward the end face 10 facing the closing cover 7 via the shoulder 11, and then merges with the flat end face 10 via a spherically chamfered pressure side face 12. The chamfering of the side surface 12 is intended to prevent the closure cover 7 from being damaged by sharp edges that may otherwise occur during introduction of the axial ram 8 into the closure cover 7 or during pressing against the hollow member. And The height of the shoulder portion 11 is the same as that of the combined wall thickness of the hollow member 6 and the closing cover 7. If the closing cover 7 has already been inserted gently into the hollow member 6 in advance, the hollow member 6 together with the closing cover 7 is consequently arranged on the forming die 1 as an assembly to be pressed and the pressure side 12 The diameter of the axial ram 8 in this area is larger than the inner diameter of the closure cover 7. The shape of the rim 13 of the closing cover 7 substantially coincides with the spherical contour of the axial ram 8 in the region of the pressure side 12. This results in a uniform pressing of the hollow member 6 and the closure cover 7, thereby optimizing the retention of the closure cover 7 on the hollow member 6. However, when the closure cover 7 is pushed into the axial ram 8 so that they are introduced together into the forming die 1, the inner diameter of the closure cover rim 13 is naturally in the region of the pressure side 12. It is larger than the diameter of the axial ram 8. In order to achieve a suitable pressing on the hollow member 6, the closing cover rim 13 at the outer diameter of this region is oversized from end to end with respect to the inner diameter of the hollow member 6. The axial ram 8 has a central extension passage 14 that is open at the end face 10. The closure cover 7 has a central opening 15 at its base 9.

  To carry out the method, the hollow member 6 is placed in the forming die 1 and then the forming die 1 is closed. As described above, the closure cover 7 may be loosely fitted into the hollow member 6 in advance, or the closure cover 7 may be pushed toward the axial ram 8. In the latter case, the opening of the closing cover 7 is aligned with the point where the passage 14 of the axial ram 8 is open. Thus, an axial ram 8 is introduced into the end of the hollow member together with the closure cover 7 so that the closure cover 7 has a hollow member end due to its dimensions and the pressure side 12 of the axial ram 8. Pressed. The pressed assembly thus constructed is then introduced into the hollow member interior 16 via the passage 14 in the axial ram and the central opening 15 of the closure cover 7, as shown in FIG. It is placed under hydroforming pressure by a pressurized fluid pressurized by a pressure generator connected to the rear side of the passage 14. As a result of the generated hydroforming pressure, the hollow member 6 is expanded until it abuts against the cavity 4 of the forming die 1 so that an inflatable part 37 can be formed (see FIGS. 5 to 10). The forming space 5 in the die 1 is now completely filled. In principle, it is also conceivable for the closure cover 7 to be introduced continuously or simultaneously at both ends of the hollow member 6.

  FIG. 2 shows a modification of the axial ram 8 and the closing cover 7. In this case, the end face 10 of the axial ram 8 has a journal-shaped projection 17 through which the passage 14 passes. Accordingly, the closing cover 7 has a bottle-like extension 18 into which the forming projection 17 of the axial ram 8 can be fitted by matching the contours. This provides a particularly sufficient retention of the closing cover 7 of the axial ram 8. As can be seen from FIG. 4, in another structural variant of the closure cover 7, the closure edge 19 of the cover rim 13 is shaped to project radially outward to form a lip-shaped annular collar.

In a variant of the invention, as shown in FIGS. 5a and b, in the pressing assembly position, the axial ram 8 is further advanced so that it can be supplied to the region of the inflatable part 37 where sufficient hollow member material is formed. , Thereby ensuring that the hollow member 6 is expanded in a reliable manner. During the course of the axial ram 8 is formed in the hollow member 6 in the hydroforming pressure P _i, that while the thick forming section 20 is immediately adjacent to the press area, which acts in all directions as indicated by arrows, on the other hand, hollow At the continuous end of the member, the hollow member material is moved into a space 21 delimited by the closing edge 19 of the closing cover rim 13 and the opposite shoulder 11 of the axial ram 8. The thick-walled portion 20 that presses the cover rim 13 inward and the hook-like closure 22 at the end of the hollow member are clamped to ensure that the closure rim 13 locks towards its end and the axial direction achieved As a result of the fixing, the closure cover 7 is particularly sufficiently retained on the hollow member 6. After the desired expansion 37 of the hollow member 6 and the pressed assembly of the hollow member 6 and the closure cover 7 is finished, the hydroforming pressure is released and the axial ram 8 is pulled away from the hydroforming die 1; Thereafter, the forming die 1 is opened, and the completed assembly having the hollow member 6 and the closing cover 7 is taken out.

  In another variant of the invention, FIG. 6 reveals a slide 23 that is guideably integrated with the forming die 1 in a guide bore 24 that extends radially relative to the cavity 4. The closure cover 7 is prevented from coming out of the pressed assembly with the hollow member 6 due to the particularly high frictional force due to being pulled along the hollow member 6 during the retraction of the axial ram 8 after the expansion of the hollow member 6. For this purpose, the slide 23 engages in an axially extending groove 25 of the axial ram 8 which opens towards the end of the hollow member. In this position, the closing edges 19 and 26 of the cover rim 13 on the one hand and the hollow member 6 on the other hand are supported by the side walls 27 of the slide 23 facing them. The use of a plurality of radially movable slides 23 arranged circumferentially offset relative to each other improves its support and ensures that the pressed assembly is held more firmly.

  Another variation of the present invention is shown in FIG. After the inflatable portion 37 is formed, in the area to be pressed, the hollow member material is integrated with the forming die 1 in the corresponding guide bore 28 extending radially with respect to the cavity 4 of the forming die 1 so as to be guided. The ram 29 is pushed into the corresponding holes 30 in the cover rim 13 and these holes are provided during or immediately after the production of the closure cover 7.

  In another variant of the invention as shown in FIG. 8, the cavity 4 adjacent to the molding space 5 is expanded conically with a shallow opening angle towards the axial ram 8. The hollow member 6 and the closure cover 7 are pressed towards this conical expansion section of the cavity 4 during the insertion of the axial ram 8, and the surface having a contour corresponding to the part 31 of the cavity 4 has a cover rim 13 and a hollow member 6. Formed.

  FIG. 9 shows a jack bracket 32 manufactured using the method according to the invention. For the sake of clarity, the closure cover 7 with the bottle-like extension 18 is shown separated from the hollow member 6 in the figure. The hollow member 6 also has a plurality of flanges 34 at the end 33 remote from the cover 7, which are partly folded back, on the one hand as a stopper and on the other hand to the lower area of the automobile sill. To fulfill the role of A passage 36 is formed in the side wall 35 of the bracket 32 to attach the bracket 32 to the car sill or any other peripheral body region, for example by spot welding, through which the hollow member 6 passes into the adjacent inner wall. Can be easily accessed in the horizontal direction. In order to be economical with respect to process engineering, it is also conceivable that these passages 36 are produced by a drilling step during the hydroforming operation that expands the hollow member 6.

  FIG. 10 shows, as a modification of FIG. 9, a pressed assembly of the hollow member 6 and the closing cover 7 in which the closing edge 26 of the hollow member 6 projects beyond the closing edge 19 of the rim 13 of the closing cover 7. Show the goods. It should also be pointed out once again that the opening 15 in the cover base 9 serves as a receiving element for a stopper into which a jack can be fitted. Furthermore, the method according to the invention is not limited to the production of jack brackets. In addition to the bracket, the method hydroforms with a closure cover for the purpose of at least partially closing one or more holes in a component, such as a structural element of an automobile, particularly including a closure node of a frame structure. Can be used for all components that will be

Fig. 2 shows in partial exploded longitudinal section the arrangement of the hydroforming die, the hollow member, the closure cover and the axial ram of the method according to the invention. FIG. 4 shows an exploded longitudinal section of an axial ram with a closure cover with a bottle-like extension and a journal-shaped projection of the method according to the invention. FIG. 2 shows the arrangement of FIG. 1 in a position where the closure cover and the hollow member are pressed together with the introduced axial ram. Fig. 4 shows an exploded longitudinal sectional view of the method according to the invention of a hollow member and a closure cover having a closure edge shaped to project radially outwards. Fig. 4 shows a longitudinal section of the arrangement of the hydroforming die, hollow member, closure cover and axial ram in the axial ram pressing position, where the hollow member engages behind the closure cover on the rim side of the method according to the invention . Fig. 5b shows a partially enlarged view from the position of the closure cover engaged behind Fig. 5a. Fig. 4 shows a layout of the hollow member, the closing cover and the hydroforming die and the axial ram in the axial ram pressing position, wherein the slide acts on the closing edge of the hollow member and the closing cover of the method according to the invention. FIG. 4 shows a layout view of a hydroforming die, hollow member, axial ram, and closure cover having a ram that moves hollow member material into a hole in the closure cover according to the present invention. FIG. 7b shows a partially enlarged view from the pressed assembly of the hollow member and closure cover shown in FIG. 7a in a position where the hollow member material has been moved into the hole in the closure cover. FIG. 4 shows a longitudinal section of the arrangement of the hydroforming die, axial ram, hollow member and closure cover in a pressing position with a section of the forming die cavity extending conically towards the axial ram of the method according to the invention. . Fig. 3 shows an exploded side view of a jack bracket according to the present invention. FIG. 10 shows a perspective view of the jack bracket from FIG. 9 after pressing the hollow member and the closure cover.

Claims (13)

  A method of manufacturing a hollow member (6) having an inflating part (37) provided with a closing cover (7) at an end, wherein the cup-shaped cover (7) is pushed into the hollow member (6) and the hollow A member (6) is placed in the hydroforming die (1), then the hydroforming die (1) is closed and the edge side of the cover (7) is radially directed towards the surrounding hollow member (6) An axial ram (8) is introduced into the cover (7) and the end of the hollow member so as to be pressed against the hollow member, and then the hollow member (6) is expanded by hydroforming pressure. how to.   The method according to claim 1, characterized in that the cover (7) is loosely fitted into the hollow member (6) outside the hydroforming die (1).   The cover (7) is sent to the hollow member (6) arranged in the hydroforming die (1) by the axial ram (8), and the pressing is performed when this feeding operation is performed. The method of claim 1, wherein:   The cover (7) is designed to have an outer diameter larger than the inner diameter of the hollow member (6) before being inserted. Method.   The cover rim (13) is clamped in place by the hollow member (6) by the combined hydroforming pressure simultaneously with the axial progression of the axial ram (8), and the material of the hollow member is the hydroforming pressure. Is moved into a space (21) delimited by a closed edge (19) of the cover rim (13) and an opposing shoulder (11) of the axial ram (8). 5. A method according to any one of claims 1 to 4, characterized in that   An opening (15) is formed in the cover base (9), and the hollow member (6) passes through the passage (14) of the axial ram (8) and the opening (15) of the cover base (9). The method according to claim 1, wherein the method is expanded by a pressurized fluid introduced into the hollow member.   A bottle-like extension (18) is formed around the opening (15) of the cover base (9) in the cover (7), and the extension (18) is connected to the end of the axial ram (8). 7. Method according to claim 6, characterized in that a molding projection (17) in the form of a hollow journal on the part side (10) is introduced.   After the hollow member (6) has been expanded, the axial direction is integrated in the hydroforming die (1) so that it can be guided and opened toward the end side (10) of the axial ram. The closed edge (26) of the hollow member (6) and the cover rim (13) is subjected to the action of a slide (23) engaged in a groove (25) extending in the axial direction of the ram (8). The method according to any one of claims 1 to 7.   9. A method according to any one of the preceding claims, characterized in that the closing edge (19) of the cover rim (13) is shaped to project radially outward.   After the cover rim (13) is drilled and the cover (7) is pressed against the hollow member (6), the material of the hollow member is integrated so as to be guided in the hydroforming die (1). 10. A method according to any one of the preceding claims, characterized in that the ram (29) is pressed into holes (30) respectively formed in the cover rim (13).   The hydroforming die (1), wherein the hollow member (6) and the cover (7) expand conically toward the axial ram (8) when the axial ram (8) is introduced. 11. Pressing toward a compartment (31) of the cavity (4) to form a contoured surface of the cover rim (13) and the hollow member (6). The method as described in any one of.   An automotive jack bracket (32) formed using a hollow member (6) manufactured as claimed in any one of the preceding claims, wherein the hollow member is remote from the cover. A bracket (32) attached to the lower region of the automobile sill that employs a flange (34) disposed at the end (33) of (6).   Jack bracket according to claim 12, characterized in that the bracket (32) has an opening (15) in the cover base (9) forming a receiving element for a stopper to which a jack can be attached.

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