Suspension arm for motor vehicle and method of manufacture thereof

Abstract

On at least one surface of a structural part, on all or part of a hollow section between outer and inner peripheral borders, is associated at least one cover sheet made of rigid metallic material. The at least one cover sheet is mechanically fixed with the edge of the peripheral borders of the structural part, and covers all or part of inner cavities formed on open sides of the part. The at least one cover sheet has a triple function: to increase the rigidity of the structural part, to absorb shock by deforming in a plane while remaining integral with the part, and to allow reduction of the mass of the structural part and optimization of the mass/performance ratio.

Claims

1. A method of manufacturing a hollow assembly of a structural part and at least one planar cover sheet, the structural part comprising a longitudinally extending mass having an open cross-sectional profile not limited to type H or U, comprising: obtaining the structural part by at least one of a casting operation and a forging operation, associating on at least one open side surface of the mass on all or part of a hollow inner cavity between peripheral borders at least one planar cover sheet made of rigid metallic material, the peripheral borders consisting of upright walls extending transversely from a central portion of said mass, the upright walls each defining a wall thickness having a top surface, and mechanically fixing the at least one planar cover sheet on the top surface of the upright walls of said peripheral borders of the mass, wherein the at least one planar cover sheet covers all or part of the hollow inner cavity, extends at least partly beyond the at least one hollow inner cavity, covers part of the top surface, and terminates along the top surface of the upright walls of the peripheral borders at a position overlapping the upright walls, and wherein the at least one cover sheet increases rigidity of the assembly, and absorbs shock by deforming in a plane while remaining integral with the structural part.

2. A hollow assembly of a structural part and at least one planar cover sheet, the structural part being obtained by at least one of a casting operating and a forging operation, the hollow assembly comprising: the structural part comprising: a longitudinally extending mass having an open cross-sectional profile, not limited to type H or U, with peripheral borders defining at least one inner hollow cavity on at least one open side surface of the mass; and ends arranged with fixing areas; wherein the peripheral borders consist of upright walls extending transversely from a central portion of said mass, the upright walls each having a wall thickness defining a top surface; and the at least one planar cover sheet having a profile similar to the structural part, the at least one cover sheet positioned and fixed on the top surface of the upright walls of the peripheral borders by superimposing and fixing a connection means, said at least one planar cover sheet covering part of the top surface, wherein the at least one planar cover sheet covers all or part of the at least one inner hollow cavity, in bearing contact with the top surface of the upright walls of the peripheral borders, the at least one planar cover sheet terminating along said top surface at a position overlapping the upright walls, and wherein the at least one planar cover sheet increases rigidity of the assembly, and the at least one planar cover sheet absorbs shock by deforming in a planar while remaining integral with the structural part.

3. The assembly as claimed in claim 2, wherein the structural part has an opening, and the at least one planar cover sheet has a corresponding opening.

4. The assembly as claimed in claim 2, wherein the at least one planar cover sheet is made of metallic material compatible for mechanical fixing with material of the structural part.

5. The assembly as claimed in claim 2, wherein the at least one planar cover sheet is fixed on the top surface of the upright walls of the peripheral borders of the structural part by welding, screwing, gluing, riveting, brazing, or another mechanical connection.

6. The assembly according to claim 2, wherein the structural part is configured as a vehicle part.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) The object of the invention is illustrated without limitation in the figures of the drawings wherein:

(2) FIGS. 1 and 2 are top views of a sample of structural parts according to the prior art with the identification of the stress zones by the arrow (F1),

(3) FIG. 3 is a pre-assembly perspective view of a structural part used according to the invention before receiving and securing the cover sheets, in an installation example with an ‘H’ section,

(4) FIG. 4 is a view of the structural part according to FIG. 3 after assembly and fixing of the cover sheet,

(5) FIG. 5 is a cross-sectional view as per line AA of FIG. 4,

(6) FIG. 6 is a partial and perspective view of a form that is complex and different from that of the structural part shown in FIG. 3,

(7) FIGS. 7, 8 and 9 are top views of the structural part according to FIG. 6 respectively, followed by partial covering by the cover sheet, and then by full covering by the said cover sheet.

DETAILED DESCRIPTION

(8) In order to make the object of the invention more concrete, it is now described in a non-exhaustive manner illustrated in the drawing figures.

(9) The invention relates to the design and manufacture of hollow structural parts, including ground connection, which are used for example and without limitation as components for motor vehicles, heavy trucks and other vehicles of this type.

(10) These hollow structural parts include for example suspension arms, pivots, rods, wishbones non-exhaustively and are subject to very high technical and environmental stresses. These parts (10) are formed by casting, forging or obtained in accordance with the combined COBAPRESS™ method of foundry casting followed by forging according to the information provided by the aforementioned European patent. Their configuration and profile is open (transverse) and not limited to the U type or H type for example, with peripheral edges (10.1), one or more hollow inner or cavities (10.2) (10.3), for example on either side of their median connection mass (10.4) in case of an ‘H’ section. The ends (10.5) (10.6) are arranged according to requirements and the applications with fixing areas of the rings or sleeves.

(11) According to the invention, the hollow structural part (10) receives on its surface(s) comprising the opening(s), on the front and/or back sides, one or more cover sheet(s) (11-12) which have a profile additional to that of the structural part to be positioned and fixed on the edge or top surface (10.7) of each of the inner and outer peripheral borders of the structural part by superimposing. The cover sheet(s) (11-12) thus cover all or part of the inner cavities formed on the open surfaces (front and back) of the structural part.

(12) We have thus shown a partial covering in FIGS. 4 and 8, and a full covering in FIG. 9.

(13) Depending on the configuration of the hollow structural part and its application, it can have one or more openings (10.8) for specific functionalities, and in this case, or the plate(s) will have one or more openings (11.1) (12.1) as required to be in line.

(14) The hollow structural part is favourably made of metallic material, and more particularly of aluminium alloy.

(15) The cover sheet(s) (11-12) are made of metallic material compatible with the material of the structural part in order to be positioned and fixed using any method of assembly: welding, screwing, gluing, riveting, brazing, etc. and to ensure a mechanical connection by a means (13). They are, for example, flat or preformed sheets. For example, weld beads (13) are thus installed on the edge of the peripheral borders of the structural part, or are determined according to the profile of the structural part.

(16) According to another embodiment of the invention, the cover sheet(s) may be in one or more parts leaving spaces between them. The positioning of the said sheet(s) is determined by the manufacturer taking into account the specificities of the connecting plate and performance required for the part.

(17) Favourably, the invention leaves a wide adaptability with more or less complex profiles of the receiving structural part.

(18) The cover sheets (11-12) are firmly attached and welded to the structural part. These sheets have three functions, namely: They can increase the rigidity of the structural part, They help to absorb shocks inherent to the unusual and/or accidental stresses by deforming in their plane while remaining integral to the part until the structural area breaks, They also allow optimization of the mass/performance ratio.

(19) The manufacturing method of hollow structural parts obtained at least by a casting, forging or a casting-forging hybrid operation, the said parts having an open cross-sectional profile is remarkable in that we associate on at least one surface of the structural part on all or part of its apparent hollow section between its outer and inner peripheral borders at least one cover sheet made using rigid metallic material, and in that we mechanically fix the said cover sheet(s) thus associated with the edge of said peripheral borders part of the structural part; the said cover sheet(s) ensure stiffening of the structural part and absorbs shocks by deforming in their plane.

(20) The advantages are apparent from the invention and firstly highlight the innovative nature of this production, its relative simplicity of creation as it is also necessary to fully manage the connection between the structural part and the cover sheets. It emphasizes the optimization of the mass/performance ratio.

(21) Thus the solution developed and implemented by this invention presents a single part obtained by casting and/or forging, which can be carried out by means of the COBAPRESS™ method specified above, using light cast-iron alloys with mechanical characteristics and that comprises zones in order to receive a sheet increasing the stiffness. This solution allows the simultaneous casting of all the functional areas of the part by engaging the least amount of material necessary that is then stiffened by the addition of a sheet.

(22) The documents of the prior art do not meet this problem and do not suggest the solution of the invention.