Method for producing a fiber-reinforced structural hollow component

Abstract

A method for manufacturing a fiber-reinforced hollow structural component includes introducing a mold core and fibers with a matrix material into a molding tool. A first fiber unit is located between the mold core and the molding tool to at least partially form a component wall. The matrix material is cured to form the hollow structural component and the mold core is flushed out of the hollow structural component to form a component cavity. At least one channel may extend through the mold core so that after the matrix material has cured and the mold core has been flushed out, a reinforcing strut is formed. A related hollow structural component is also disclosed.

Claims

1. A method for manufacturing a fiber-reinforced hollow structural component comprising the steps of: manufacturing a mold core by rapid prototyping, the mold core including a granular material and a binding agent; introducing the mold core and a first fiber unit into a molding tool so that the first fiber unit is distributed at least partially around the mold core and is located between the mold core and the molding tool, the molding tool defining a first supply channel extending from an outside of the molding tool core to an inside of the molding tool; injecting a matrix material into the mold core via the first supply channel to at least partially form a component wall from the first fiber unit and the matrix material between the mold core and the molding tool; curing the matrix material after the introducing the mold core and a first fiber unit step and the injecting a matrix material step as a result of a change in at least one of a temperature and a pressure to form the hollow structural component; flushing the mold core out of the hollow structural component after the curing step to form a component cavity; forming at least one channel extending through the mold core during the step of manufacturing the mold core, the at least one channel having a channel opening at each end of the at least one channel; and introducing a second fiber unit through at least one of the channel openings into the at least one channel before the curing step, the first supply channel located within the molding tool so that the matrix material exiting the first supply channel is directed into the at least one channel during the injecting step so that, after the injecting, the curing, and the flushing out steps, a reinforcing element is formed from the second fiber unit and the matrix material, the reinforcing element extending through the component cavity and being connected in the area of its two ends to the component wall; wherein the first supply channel has a downstream end located in the molding tool so at to direct the matrix material into the at least one channel, the downstream end being located adjacent at least one of the channel openings so that the matrix material exits the downstream end and flows through the first fiber unit and into the at least one channel.

2. The method as claimed claim 1, wherein during the manufacturing step a second supply channel is formed in the mold core for supplying a solvent during the flushing step.

3. The method as claimed in claim 2, wherein the second supply channel is filled, before the injecting step, with a filling material and, after the curing step, the filling material is flushed out together with the mold core in the flushing step.

4. The method as claimed in claim 2, wherein during the flushing step, the solvent is flushed at least one of into the second supply channel and onto a cross-section of the mold core, so that the mold core detaches from the hollow structural component.

5. The method as claimed in claim 2, wherein the mold core expands when the temperature increases, so that the first fiber unit and the matrix material are pressed outward against a negative mold of the molding tool.

6. The method as claimed in claim 1, wherein at least one of the first fiber unit is wrapped around the mold core, the wrapped mold core is introduced into the molding tool and the matrix material is injected into the molding tool after the molding tool has been closed.

7. The method as claimed in claim 1, wherein the at least one channel defines at least two undercuts which are spaced apart in a longitudinal direction of the at least one channel.

8. The method as claimed in claim 1, wherein fibers of the second fiber unit are introduced into the at least one channel with the aid of an introduction device.

9. The method as claimed in claim 1, wherein the second fiber unit is connected, at its two ends, to a particular assigned area of the first fiber unit thereby forming two connection areas.

10. The method as claimed in claim 9, wherein at least one of the two connection areas is formed on an outer side of the first fiber unit, wherein a slot is cut into the first fiber unit and the second fiber unit is guided through the slot.

11. The method as claimed in claim 9, wherein at least one of the two connection areas is formed on an inner side of the first fiber unit, wherein the second fiber unit is introduced into the channel first, an overhanging end of the second fiber unit is folded onto a circumference of the mold core, and subsequently, the mold core is wrapped with the first fiber unit.

12. The method as claimed in claim 9, wherein at least one of the two connection areas is formed in an interior of the first fiber unit.

13. The method as claimed in claim 9, wherein the introduction device includes a needle, and wherein the second fiber unit is pierced with the needle through the first fiber unit lying around the mold core.

14. The method as claimed in claim 9, wherein an overhanging one of the ends of the second fiber unit is at least one of folded onto and sewn together with an outer side of the first fiber unit.

15. A method for manufacturing a fiber-reinforced hollow structural component comprising the steps of: manufacturing a mold core by rapid prototyping, the mold core including a granular material and a binding agent; introducing the mold core and a first fiber unit into a molding tool so that the first fiber unit is distributed at least partially around the mold core and is located between the mold core and the molding tool, the molding tool defining a first supply channel extending from an outside of the molding tool core to an inside of the molding tool; injecting a matrix material into the mold core via the first supply channel to at least partially form a component wall from the first fiber unit and the matrix material between the mold core and the molding tool; curing the matrix material after the introducing the mold core and a first fiber unit step and the injecting a matrix material step as a result of a change in at least one of a temperature and a pressure to form the hollow structural component; flushing the mold core out of the hollow structural component after the curing step to form a component cavity; forming at least one channel extending through the mold core during the step of manufacturing the mold core, the at least one channel having a channel opening at each end of the at least one channel; and introducing a second fiber unit through at least one of the channel openings into the at least one channel before the curing step, the first supply channel located within the molding tool so that the matrix material exiting the first supply channel is directed into the at least one channel during the injecting step so that, after the injecting, the curing, and the flushing out steps, a reinforcing element is formed from the second fiber unit and the matrix material, the reinforcing element extending through the component cavity and being connected in the area of its two ends to the component wall; wherein during the manufacturing step a second supply channel is formed in the mold core for supplying a solvent during the flushing step; wherein the first supply channel has a downstream end located in the molding tool so at to direct the matrix material into the at least one channel, the downstream end being located adjacent an entrance of the second supply channel so that the matrix material exits the downstream end and flows through the second supply channel and into the at least one channel between the two channel openings of the at least one channel.

16. A method for manufacturing a fiber-reinforced hollow structural component comprising the steps of: manufacturing a mold core by rapid prototyping, the mold core including a granular material and a binding agent, the manufacturing step including forming a supply channel in the mold core and filling the supply channel with a filling material; introducing the mold core and a first fiber unit with a matrix material into a molding tool so that the first fiber unit is located between the mold core and the molding tool to at least partially form a component wall; curing the matrix material after the introducing the mold core and a first fiber unit with a matrix material step as a result of a change in at least one of a temperature and a pressure to form the hollow structural component; flushing the mold core and the filling material out of the hollow structural component using a solvent after the curing step to form a component cavity; forming at least one channel extending through the mold core during the step of manufacturing the mold core; and introducing a second fiber unit and the matrix material into the channel before the curing step so that, after the curing and flushing out steps, a reinforcing element is formed from the second fiber unit and the matrix material, the reinforcing element extending through the component cavity and being connected in the area of its two ends to the component wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages of the invention are described in the following exemplary embodiments. Wherein:

(2) FIG. 1 shows a front view of a mold core,

(3) FIG. 2 shows a front view of a second exemplary embodiment of a mold core comprising a channel,

(4) FIG. 3a shows a front view of one longitudinal section half of a third exemplary embodiment of a mold core comprising a channel,

(5) FIG. 3b shows a front view of a second longitudinal section half of the third exemplary embodiment,

(6) FIG. 3c shows a sectional view of a mold core according to the third exemplary embodiment,

(7) FIG. 4 shows a sectional view of a mold core wrapped with fibers,

(8) FIG. 5 shows a diagrammatic sectional view of a molding tool comprising a mold core,

(9) FIG. 6 shows a diagrammatic sectional view of a second exemplary embodiment of a molding tool comprising a mold core,

(10) FIG. 7 shows a sectional view of one further exemplary embodiment of a molding tool comprising a mold core,

(11) FIG. 8 shows a sectional view of a structural component comprising a mold core,

(12) FIG. 9a shows a sectional view of a structural component comprising a reinforcing element, in particular a reinforcing strut, and

(13) FIG. 9b shows a sectional view of a structural component according to FIG. 9a.

DETAILED DESCRIPTION

(14) FIG. 1 shows a front view of a mold core 1. The mold core 1 is provided for manufacturing a non-represented hollow structural component 2 (cf. FIGS. 9a, 9b). The mold core 1 is preferably formed from granules, in particular sand, which are held together via a binding agent, in particular an adhesive. In addition, the mold core 1 expands preferably as a result of a temperature increase, and so its volume 3 increases.

(15) In the following description of the alternative exemplary embodiments of the mold core 1 represented in FIGS. 2 to 3c, identical reference numerals are utilized for features which are identical and/or at least comparable in terms of their design and/or mode of operation as compared to the first exemplary embodiment represented in FIG. 1. If these features are not explained again in detail, their design and/or mode of operation correspond to the design and mode of operation of the features already described above.

(16) FIG. 2 shows a second exemplary embodiment of the mold core 1 which is preferably designed as a single piece in this case. The mold core 1 comprises a channel 4 including a first channel opening 5 and a second channel opening 6. The channel 4 is preferably primarily formed together with the mold core 1 in a rapid prototyping method, in particular a 3D printing method. Moreover, the channel 4 extends through the entire mold core 1 or, according to the figure, across its entire height. The channel 4 is designed to be straight in the present case. In one exemplary embodiment which is not represented here, the channel 4 can be additionally or alternatively sharply bent and/or, as represented in FIGS. 3a and 3b, curved. Additionally or alternatively, it is advantageous when the channel 4 is designed to include at least two undercuts which are spaced apart from each other in the longitudinal extension or longitudinal direction (cf. FIGS. 3a and 3b). The channel 4 can also have a freeform geometry. The channel 4 can also be composed of multiple protruding sections which are identical and/or which differ from each other.

(17) FIGS. 3a and 3b each show one half of a multiple-part mold core 1 comprising a primarily formed channel 4 which has been manufactured, in particular, in a rapid prototyping method. FIG. 3c shows a cross-sectional view of this mold core which has been assembled. The mold core 1 comprises a first mold core part 7 and a second mold core part 8. In order to form the channel 4, a first longitudinal section half 9 is primarily formed in the first mold core part 7 and a second longitudinal section half 10 is primarily formed in the second mold core part 8. The two longitudinal section halves 9, 10 correspond to each other, so that, when assembled, they form the channel 4. The two mold core parts 7, 8 are connected to each other, in particular being glued, for this purpose. Alternatively, the mold core 1 can also be designed as a single piece.

(18) FIG. 4 shows a mold core 1 which is wrapped with a first fiber unit 11. The first fiber unit 11 is formed from a multitude of fibers 12a and can comprise several fiber layers lying one on top of the other. In this case, it is irrelevant whether the fibers 12a are staple fibers, continuous fibers, or the like. It is also conceivable that the first fiber unit 11 is formed by at least one fiber mat. In addition, the mold core 1 comprises a second fiber unit 13. The second fiber unit is formed by fibers 12b.

(19) The fibers 12b are guided through the channel 4 and/or the first fiber unit 11 with the aid of an, in particular mechanical and/or pneumatic, introduction device 31, in particular with the aid of a nozzle (not represented) or a needle 14. The at least one fiber 12b is guided through the mold core 1, in particular its channel 4, with the aid of the introduction device 31, and remains at least partially therein. The second fiber unit 13 is formed by way of the introduction of multiple fibers 12b. The second fiber unit 13 is guided, in particular pierced, through the first fiber unit 11 and the mold core 1. The two channel openings 5, 6 are formed on an outer side 17 of the first fiber unit 11.

(20) The channel 4 is formed before the wrapping of the mold core 1 together therewith, by way of a primary forming method, in particular a rapid prototyping method.

(21) In order to guide or pierce the second fiber unit 13 through the first fiber unit 11, a slot (not shown) and/or an opening can be introduced, in particular cut, into the first fiber unit 11. The overhanging ends 20 of the fibers 12b of the second fiber unit 13 are folded onto the outer side 17 of the first fiber unit 11, so that the ends 20 can be connected to the first fiber unit 11 while forming a connection area 21 in each case.

(22) In addition, the fiber layer of the first fiber unit 11 can be wrapped, on its outer side, with a second layer (not shown here), so that the ends 20 are embedded between these two fiber layers.

(23) The channel 4 is primarily formed together with the mold core 1 before the introduction of the fibers 12b. The fibers 12b of the second fiber unit 13 can then be brought into the channel 4, in particular being drawn through or injected, with the aid of the introduction device 31, in particular with the aid of the needle 14 or an air flow. According to FIG. 4, the needle comprises, at its one end, a tip 15 for easy introduction and, at its other end, an eye 16 for accommodating at least one part of the second fiber unit 13.

(24) FIG. 5 shows a molding tool 18, in which the mold core 1 is situated together with the two fiber units 11, 13. In the represented exemplary embodiment, the fibers 12a of the first fiber unit 11 were wrapped around the mold core 1 or introduced into its channel 4 in alternation with the fibers 12b of the second fiber unit 13 before the mold core 1 was introduced into the molding tool 18. As a result, the connection areas 21 are formed in the interior of the first fiber unit 11.

(25) Matrix material 22 is injected into the molding tool 18 in order to fix the fibers 12a, 12b of the two fiber units 11, 13. The matrix material 22 is pressed through the first fiber unit 11 into the channel 4 comprising the second fiber unit 13. The two fiber units 11, 13 are embedded into the matrix material 22 as a result. After the injection of the matrix material 22, the matrix material 22 is cured as a result of a change in pressure and/or temperature. In this case, the mold core 1 expands in such a way that at least the first fiber unit 11 with the matrix material 22 is pressed against a negative mold 23 of the molding tool 18. As a result, the two fiber units 11, 13 impregnated with the matrix material 22 also retain their predefined shape after the curing of the matrix material 22.

(26) In the following description of the alternative exemplary embodiments of the molding tool 18 represented in FIGS. 6 and 7, identical reference signs are utilized for features which are identical and/or at least comparable in terms of their design and/or mode of operation as compared to the first exemplary embodiment represented in FIG. 5. If these features are not explained again in detail, their design and/or mode of operation correspond to the design and mode of operation of the features already described above.

(27) FIG. 6 shows the molding tool 18 comprising a supply channel 24. The supply channel 24 can be primarily formed together with the at least one channel 4 and the mold core 1, in particular in a rapid prototyping method. The supply channel 24 is connected to the channel 4 in the area between the two channel openings 5, 6. The matrix material 22 is injected into the channel via the supply channel 24, preferably in such a way that the first fiber unit 11 is also impregnated with the matrix material 22. After the matrix material 22 has cured, it is possible to flush out the mold core 1 via the supply channel 24. The combination of the embodiment of the molding tool described in FIGS. 5 and 6 is conceivable.

(28) FIG. 7 shows the molding tool 18 comprising the supply channel 24. In contrast to FIG. 6, a filling material 25 is filled into the supply channel 24 in this case. The filling material 25 is preferably an expansion material such as wax. The matrix material 22 is pressed via the first channel opening 5 through the first fiber unit 11 into the second fiber unit 13. As a result, the two fiber units 11, 13 are embedded into the matrix material 22. Moreover, it is possible to fill the channel 4 with the matrix material 22 without the second fiber unit 13 having been situated therein in advance. Due to the filling material 25, it is ensured that the matrix material 22 only enters the channel 4, and not the supply channel 24 itself. After the matrix material 22 has cured, the filling material 25 is flushed out of the supply channel 24. As a result, the supply channel 24 retains its advantageous effect, namely that the mold core 1 can be rapidly flushed out via the supply channel 24.

(29) FIG. 8 shows the two fiber units 11, 13 embedded into the matrix material 22 after the matrix material 22 has cured. The mold core 1 is still situated so as to be surrounded by the fiber unit 11 and the matrix material 22. The connection areas 21 are formed on an inner side 27 of the first fiber unit 11 in this case. The second fiber unit 13 is introduced into the channel 4 before the first fiber unit 11 is wrapped or placed around the mold core 1. The overhanging ends 20 of the fibers 12b of the second fiber unit 13 are folded onto a circumference 28 of the mold core 1.

(30) A solvent L is flushed into the supply channel 24 in order to remove the mold core 1 for forming the hollow structural component 2. The soluble mold core 1, in particular its soluble binding agent, detaches from the structural component 2 as a result. The first fiber unit 11 embedded into the matrix material 22 therefore forms a component wall 19 of the hollow structural component 2. The second fiber unit 13 embedded into the matrix material 22 forms a reinforcing element, in particular a reinforcing strut 26 (cf. FIGS. 9a, 9b). The solvent L can also be flushed onto a cross-section 30 of the mold core 1.

(31) FIGS. 9a and 9b show different views of the hollow structural component 2 formed according to the described manufacturing method. The hollow structural component 2 comprises the component wall 19. The component wall 19 delimits a component cavity 29. The reinforcing element, in particular the reinforcing strut 26, extends through the component cavity 29. The reinforcing element, in particular the reinforcing strut 26, is connected at its two ends 20 to the component wall 19 via the particular assigned connection area 21.

(32) The present invention is not limited to the exemplary embodiments which have been represented and described. Modifications within the scope of the claims are also possible, as is any combination of the features, even if they are represented and described in different exemplary embodiments.

LIST OF REFERENCE NUMERALS

(33) 1 mold core

(34) 2 hollow structural component

(35) 3 volume

(36) 4 channel

(37) 5 first channel opening

(38) 6 second channel opening

(39) 7 first mold core part

(40) 8 second mold core part

(41) 9 first longitudinal section half

(42) 10 second longitudinal section half

(43) 11 first fiber unit

(44) 12a fiber of the first fiber unit

(45) 12b fiber of the second fiber unit

(46) 13 second fiber unit

(47) 14 needle

(48) 15 tip

(49) 16 eye

(50) 17 outer side

(51) 18 molding tool

(52) 19 component wall

(53) 20 ends

(54) 21 connection area

(55) 22 matrix material

(56) 23 negative mold

(57) 24 supply channel

(58) 25 filling material

(59) 26 reinforcing strut

(60) 27 inner side

(61) 28 circumference

(62) 29 component cavity

(63) 30 cross-section

(64) 31 introduction device

(65) L solvent