Method for manufacturing a metallic structural component provided with a composite reinforcement

Abstract

A method for manufacturing a metallic structural component provided with a composite reinforcement comprises the steps of providing a batch or slab (9) made of a composite material; preparing a structural element (12) made of a metallic material of a vehicle; arranging said batch or slab (9) upon a portion of said structural element (12); and applying pressure to said batch or slab (9) so that said batch or slab, in pressing against the portion of said structural element (12), deforms itself until it covers at least part of the contour of said portion of the structural element (12).

Description

[0001] Method for manufacturing a metallic structural component provided with a composite reinforcement

[0002] Technical field

[0003] The present invention is generally in the automotive sector; in particular, the invention relates to a method for manufacturing a metallic structural component, provided with a composite reinforcement, and a metallic structural component provided with a composite reinforcement.

[0004] Summary of the invention

[0005] Hybrid structures are known that are intended for use in the automotive sector, for example suspension arms made of a composite material, that encompass metallic reinforcements (typically coupling means, such as pins, pegs or bushings) and that are incorporated into the composite matrix by means of co-molding or over-molding.

[0006] One example of such a solution is known from the document WO 2022049558 Al.

[0007] Using such a technique it is possible to produce manufactured articles wherein the structure thereof, which is eminently composite, is locally reinforced by means of the incorporation or partial embedding of metallic inserts.

[0008] With respect to equivalent structural elements, however, which are traditionally made of metal (for example the suspension components of a motor vehicle, such as cross members or suspension knuckles), such manufactured articles may not always provide the same mechanical performance. Furthermore, when production lines are already set up to manufacture such metallic components, it becomes difficult to replace the latter with composite components, which replacement would require a radical change to the production system.

[0009] Contrary to the prior art, wherein structural composite elements incorporate reinforcing metallic inserts, the present invention proposes a solution for a vehicle structural component, for example a suspension element, that is made of metal with reinforcing zones made of a composite material.

[0010] According to a preferred embodiment, the object of the present invention is to provide a new type of hybrid metallic-composite suspension knuckle that, unlike a traditional composite structure using a plurality of metallic inserts therein, has a metallic knuckle that is locally reinforced at one or more of the appendages thereof, by means of the aid and application of composite materials that are expediently reinforced.

[0011] To achieve this, according to the invention, the metallic structural element (for example, a cross member or a suspension knuckle) is used as a counter-mold for making the composite reinforcement element.

[0012] This can be achieved by applying patches or reinforcement parts to the metallic element by means of the use of an interposed structural adhesive or viscoelastic means, suitable for joining together metallic and composite components, or in the absence of an interposed adhesive means, identifying the resin, constituting said composite material, as a means for ensuring the joining of such components. This solution allows for the simultaneous construction of the reinforcing element made of a composite material and the activation of the adhesive polymerization and consolidation processes.

[0013] According to one embodiment, a plate made of carbon or glass fiber-reinforced composite material is applied to the metallic structural element by means of a sheet material compression molding process (SMC or “sheet molding compound”, PMC or “Pre-preg molding compound” material, with fibers impregnated with thermosetting resins, e.g., epoxy or vinyl ester resins).

[0014] According to one embodiment, a multilayer composite material is provided, wherein the slabs thereof are prepared in such a way that upon the first layer (namely, upon the face of that plate that is intended to come into contact with the metallic component) there is a layer of structural adhesive (for example, a paste or tape). The composite batches may be deposited in a half-mold, having a cavity with a shape that is complementary to the imprint of the metallic blank (e.g., the suspension knuckle to be locally reinforced), which in turn is arranged so as to act as a counter-mold for the aforesaid composite batches. The batches are then arranged in direct contact with the outer surface of the structural element, and the mold closed, applying pressure so as to adapt and adhere the reinforcing plate to the metallic element, possibly in such a way that the first completely wraps around that portion of the second that is intended to be reinforced (this would allow a single reinforcing element to be made that is directly glued to the reinforcing surface, without the need to break it down into two shells that are adapted to reproduce the surface of the element to be reinforced).

[0015] In an alternative embodiment, the reinforcement plates are arranged directly upon the metallic structural element, and the assembly thus obtained is incorporated into a vacuum bag that ensures the elimination of any residual air present between any layers of the plate. The assembly is then arranged inside an autoclave and vacuum-loaded using the application of pressure and temperature so as to allow for the consolidation of the composite reinforcement and the adhesion thereof to the metallic structural element.

[0016] One solution according to the present invention is further distinct from the prior art in that there is no need to preform the composite plate, which is instead modeled at the same time as the gluing to the metallic structural element.

[0017] The aforesaid and other objects and advantages are achieved, according to one aspect of the invention, by a method for manufacturing a metallic structural component, provided with a composite reinforcement, and a metallic structural component provided with a composite reinforcement, having the features defined in the appended claims.

[0018] Brief description of the drawings

[0019] The functional and structural features of some preferred embodiments of one solution according to the invention will now be described. Reference is made to the accompanying drawings, wherein:

[0020] - Fig. 1 and 2 are two schematic perspective views of a reinforced structural element according to one embodiment of the present invention, and show, respectively, a metallic blank structural element and the same metallic structural element provided with a reinforcement made of a composite material; and

[0021] - Fig. 3 to 10 are schematic views of respective steps of a process for applying a reinforcement, made of a composite material, to a metallic structural element, according to one embodiment of the present invention.

[0022] Detailed description

[0023] Before explaining in detail a plurality of embodiments of the invention, it should be clarified that the invention is not limited in the application thereof to the design details and configuration of the components presented in the following description or shown in the drawings. The invention may assume other embodiments and be implemented or constructed in practice in different ways. It should also be understood that the phraseology and terminology have a descriptive purpose and should not be construed as limiting.

[0024] Referring by way of example to Figs. 1 and 2, a reinforced structural element according to the invention comprises a structural element 12 of a vehicle, made of a metallic material (a suspension knuckle in the example shown), having a portion (an arm or appendage of the suspension knuckle, suspension, adapted to connect said knuckle to other elements of the suspension system) on which a reinforcing plate 15 made of a composite material is applied.

[0025] According to one aspect of the invention, a method for manufacturing a metallic structural component provided with a composite reinforcement comprises the steps of providing a batch or slab 9 made of a composite material, providing a structural element 12 made of a metallic material of a vehicle, arranging said batch or slab 9 upon a portion of said structural element 12, and applying pressure to said batch or slab 9 so that said batch or slab, in pressing against the portion of said structural element 12, deforms itself until it covers at least part of the contour of said portion of the structural element 12. These steps are schematically visible in the sequence of Fig. 3 to 6. According to a preferred embodiment, the structural element 12 is an automotive suspension component, for example a cross member or a suspension knuckle.

[0026] The suspension knuckle may, for example, be made of aluminum by means of forging, die casting, etc. The casting blank may then be subjected to a sandblasting surface treatment of those area(s) on which the composite reinforcement is to be applied.

[0027] Preferably, the portion of the structural element 12 on which the composite batch or slab 9 lies is an arm of a suspension knuckle.

[0028] According to one embodiment, the step of applying pressure to the batch or slab 9, insofar as the latter covers the portion of the structural element 12, is performed in ensuring that the portion of the structural element 12 is wrapped with a composite material solely from one side of said portion, on which a single batch or slab 9 initially lies. In other words, the structural element 12 is coated from only one side so that the coating is formed from a single reinforcing plate 15 made of a composite material, and not from two opposing plates. According to this embodiment, the coating may then close around the portion of the structural element 12 in such a way as to seamlessly encircle the entire perimeter or contour thereof.

[0029] According to an alternative embodiment, the steps are provided for preparing two batches or slabs 9 of composite material, and laying said batches or slabs 9 on opposite sides of said portion of the structural element 12, so that, by implementing the compression step of the batches or slabs 9, the portion of the structural element 12 is covered with composite material starting from two opposite sides thereof. According to this embodiment, the coating may then close around the portion of the structural element 12 in such a way as to seamlessly encircle the entire perimeter or contour thereof.

[0030] According to one embodiment, illustrated by way of example in Fig. 7 to 10, the step of applying pressure to the batch or slab 9, so that the latter covers the portion of the structural element 12, includes the sub-steps of preparing a mold 14, comprising two half-molds which jointly define a cavity adapted to receive said batch or slab 9 and at least said portion of the structural element 12; inserting the batch or slab 9 into the cavity of one half-mold and said portion of the structural element 12 into the cavity of the other half-mold, so that the batch or slab 9 faces the portion of the structural element 12; and closing the mold 14, applying pressure and heat to the batch or slab 9 until it fits the outer surface of said portion of the structural element 12.

[0031] According to an alternative embodiment (not shown), the step of applying pressure to the batch or slab 9, so that the latter covers the portion of the structural element 12, includes the sub-steps of providing an autoclave vacuum bag; inserting the batch or slab 9 and the portion of the structural element 12 into the vacuum bag, so that the batch or slab 9 faces the portion of the structural element 12; inserting the vacuum bag into an autoclave; and applying a vacuum inside said vacuum bag, applying pressure and heat to the vacuum bag until the batch or slab 9 fits the outer surface of said portion of the structural element 12.

[0032] The batch or slab 9 may comprise one or more layers of a fibrous material reinforced with a polymer matrix 10.

[0033] The batch or slab 9 may comprise a layer treated with an adhesive material 11, said layer being adapted to come into direct contact with the outer surface of the portion of the structural element 12 and to adhere the composite coating to the structural element 12.

[0034] Various aspects and embodiments of a method for manufacturing a metallic structural component, provided with a composite reinforcement, and a metallic structural component provided with a composite reinforcement according to the invention have been described. It is understood that each embodiment may be combined with any other embodiment. Moreover, the invention is not limited to the embodiments described, but may be varied within the scope defined by the appended claims.

Claims

CLAIMS1. A method for manufacturing a metal structural component provided with a composite reinforcement, comprising the steps of: a) providing a batch or slab (9) of a composite material; b) providing a vehicle structural element (12) made of a metallic material; c) placing said batch or slab (9) so that it lies on a portion of said structural element (12); and d) applying pressure to said batch or slab (9), so that the latter, pressed against said portion of said structural element (12), deforms itself until it covers at least part of the contour of said portion of the structural element (12).

2. The method according to claim 1, wherein the structural element (12) is a component of an automotive suspension.

3. The method according to claim 2, wherein the structural element (12) is a suspension cross member or a suspension knuckle.

4. The method according to claim 3, wherein the portion of the structural element (12) on which the composite batch or slab (9) rests is an arm of a suspension knuckle, adapted to connect said knuckle to other elements of the suspension system.

5. The method according to any one of the preceding claims, wherein step (d) is carried out by causing the portion of the structural element (12) to be wrapped by a composite material solely from one side of said portion, on which a single batch or slab (9) initially lies.

6. The method according to any one of claims 1 to 4, comprising the steps of providing two batches or slabs (9) of a composite material, and arranging said batches or slabs (9) so as to lay on opposite sides of said portion of the structural element (12), so that, by carrying out step (d), the portion of the structural element (12) is covered with composite material from two opposite sides thereof.

7. The method according to any of the preceding claims, wherein step (d) includes the sub-steps of: e) providing a mold (14), comprising two half-molds jointly defining a cavity adapted to receive said batch or slab (9) and at least said portion of the structural element (12); f) inserting the batch or slab (9) into the cavity of one half-mold and said portion of the structural element (12) into the cavity of the other half-mold, so that the batch or slab (9) faces the portion of the structural element (12); and g) closing the mold (14) in applying pressure and heat to the batch or slab (9) until it conforms itself to the outer surface of that portion of the structural element (12).

8. The method according to any one of claims 1 to 6, wherein step (d) includes the substeps of: h) providing an autoclave vacuum bag; i) inserting the batch or slab (9) and the structural element portion (12) into the vacuum bag so that the batch or slab (9) faces the structural element portion (12); j) inserting the vacuum bag in an autoclave; and k) applying a vacuum inside said vacuum bag, applying pressure and heat to the vacuum bag until the batch or slab (9) fits on the outer surface of said portion of the structural element (12).

9. The method according to any one of the preceding claims, wherein the batch or slab (9) comprises one or more layers of fiber-reinforced material with a polymer matrix (10).

10. The method according to any one of the preceding claims, wherein the batch or slab (9) comprises a layer treated with adhesive material (11), said layer being adapted to come into direct contact with the outer surface of the portion of the structural element (12) and of adhering the composite coating to the structural element (12).

11. A reinforced structural element, comprising a vehicle structural element (12) made of a metallic material, such as a cross-member or a suspension knuckle, having a portion to which a reinforcement plate (15) of a composite material is applied.

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