Tool for internal high-pressure shaping and method for shaping a workpiece by internal high-pressure shaping

Abstract

A tool for the internal high-pressure shaping of a workpiece, in particular for producing a tubular structural component for a motor vehicle, is provided. The tool includes at least three movable tool segments, which bound a shaping cavity for accommodating and shaping the workpiece. The movable tool segments, at least in some sections, completely form the shaping cavity in a closed state of the tool. A method for shaping a workpiece by internal high-pressure shaping is also provided.

Claims

1. An apparatus for hydroforming a tubular hollow body, comprising: a tool that includes: four movable tool segments which delimit a shaping cavity for accommodating and forming the tubular hollow body, wherein, in a closed state of the tool, the four movable tool segments fully form the shaping cavity and at least a part of each of the four movable tool segments is in direct contact with a totally enclosed circumferential body that defines the tubular hollow body, wherein the tool is designed such that, the tubular hollow body is formed by a forming process in the tool by using a high internal fluid pressure, there is a respective parting line between two directly adjacent movable tool segments and no portion of any of the respective parting lines is in direct contact with the tubular hollow body such that the tubular hollow body is not in contact with any of the respective parting lines during an entirety of the forming process of the tubular hollow body in the tool by using the high internal fluid pressure.

2. The apparatus according to claim 1, wherein, in the closed state of the tool, at least parts of the four movable tool segments fully form the shaping cavity such that, in an imaginary cross sectional plane, a closed encircling cavity outline is formed by the four movable tool segments.

3. The apparatus according to claim 2, wherein, in the closed state of the tool, each of the four movable tool segments is in direct contact with two further movable tool segments.

4. The apparatus according to claim 1, wherein, in the closed state of the tool, each of the four movable tool segments is in direct contact with two further movable tool segments.

5. The apparatus according to claim 1, wherein the tubular hollow body is a tubular structural component for a motor vehicle.

6. A method for forming a tubular hollow body by hydroforming, the method comprising the acts of: supplying a tool comprising: four movable tool segments which delimit a shaping cavity for accommodating and forming the tubular hollow body, wherein, in a closed state of the tool, at least parts of the four movable tool segments fully form the shaping cavity; supplying the tubular hollow body which is to be formed; and forming the tubular hollow body by a forming process in the tool using a high internal fluid pressure, wherein, during the forming process in the tool by using the high internal fluid pressure, at least a part of all of the four movable tool segments of the tool is in direct contact with a totally enclosed circumferential body that defines the tubular hollow body and there is a respective parting line between two directly adjacent movable tool segments, wherein no portion of any of the respective parting lines is in direct contact with the tubular hollow body such that the tubular hollow body is not in contact with any of the respective parting lines during an entirety of the forming process of the tubular hollow body in the tool by using the high internal fluid pressure.

7. The method according to claim 6, wherein, in the closed state of the tool, the four movable tool segments form a closed encircling cavity outline.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1 to 4 are various schematic illustrations of a prior-art tool for hydroforming a workpiece.

(2) FIGS. 5 to 8 are various schematic illustrations of exemplary embodiments of a tool described here, and of a method described here.

DETAILED DESCRIPTION OF THE DRAWINGS

(3) In the exemplary embodiments and figures, the same or equivalent constituent parts can each be provided with the same reference signs. The elements illustrated and the proportions thereof in relation to one another should basically be considered as not being to scale. Rather, to give a clear illustration and/or a better understanding, individual elements may be illustrated in exaggeratedly thick form or with exaggeratedly large dimensions.

(4) FIGS. 1 to 4 show schematic illustrations of various views of a prior-art tool 1, and of a method, for hydroforming a workpiece 2. FIG. 1 shows a schematic perspective illustration. FIGS. 2 to 4 show sectional illustrations, wherein FIG. 2 shows the tool 1 in an open state, FIG. 4 shows the tool 1 in the closed state, and FIG. 3 shows an enlarged detail G from FIG. 2.

(5) The tool 1 has a first tool segment 3 and a second tool segment 4, in the closed state 10 of the tool 1, the two tool segments 3, 4 form a closed cavity 7. FIGS. 2 to 4 each show the workpiece 2 in two different illustrations, that is to say in an illustration prior to the forming operation and in an illustration following the forming operation.

(6) The disadvantage with the method shown in conjunction with FIGS. 1 to 4 is that the parting line, which is formed between the tool segments 3, 4, is in direct contact with the workpiece 2 during the forming operation.

(7) The operation of coordinating the parting line can be a very laborious one as far as the design or production of the tool 1 is concerned.

(8) Furthermore, it is not possible for the tool 1 shown in conjunction with FIGS. 1 to 4 to form any undercut components. In addition, depending on the component, one or more process steps in which the workpiece 2 has to be performed may be necessary.

(9) FIGS. 5 to 8 show various schematic illustrations of an exemplary embodiment of a tool 1 for hydroforming a workpiece 2. FIG. 5 here shows a perspective view of the tool 1 and of a workpiece 2 which is to be, and has been, formed. FIGS. 6 to 8 are sectional illustrations, wherein FIG. 6 shows the tool 1 in an open state, FIG. 8 shows the tool 1 in the closed state, and FIG. 7 shows an enlarged detail H from FIG. 6.

(10) The tool 1 is designed in the form of a hydroforming tool and has four movable tool segments 3, 4, 5, 6, which delimit a shaping cavity 7 for accommodating and shaping a workpiece 2. In the closed state 10 of the tool 1, at least parts of the four movable tool segments 3, 4, 5, 6 fully form the shaping cavity, to be precise such that, in an imaginary cross-sectional plane, a closed encircling cavity outline is formed by the four movable tool segments 3, 4, 5, 6.

(11) Furthermore, in the closed state 10 of the tool 1, the individual movable tool segments 3, 4, 5, 6 are each in direct contact with two further movable tool segments 3, 4, 5, 6.

(12) When the workpiece 2 is being formed using a high internal fluid pressure, for example by virtue of a water/oil emulsion being introduced into the workpiece 2, designed in the form of a hollow body, the workpiece 2, in the closed state 10 of the tool 1, is not in contact throughout with the surface of the cavity 7. In particular in regions of the parting lines 8, which are formed between two tool segments 3, 4, 5, 6, the workpiece 2 is not in contact with surface sub-regions 9 of the cavity 7.

(13) This advantageously makes it possible to dispense with laborious coordination of the parting lines 8. Furthermore, the risk of a component formed containing an offset on account of a poorly formed parting line 8 can be ruled out.

(14) The tool 1 shown here in conjunction with FIGS. 5 to 8, and the method described in conjunction with FIGS. 5 to 8, is/are also advantageously suitable for forming workpieces 2 which have an undercut. Furthermore, the tool 1 can avoid preforming of workpieces 2, which is imperative in the prior art.

(15) The features described in the exemplary embodiments shown can also be combined with one another in accordance with further exemplary embodiments. As an alternative, or in addition, the exemplary embodiments shown in the figures can have further features as per the embodiments of the general description.

LIST OF REFERENCE SIGNS

(16) 1 Tool 2 Workpiece 3 First tool segment 4 Second tool segment 5 Third tool segment 6 Fourth tool segment 7 Cavity 8 Parting line 9 Surface sub region 10 Closed state G, H Enlarged detail

(17) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.