Method for obtaining a welded joint between elements of different materials, and a hybrid component obtained through this method

Patent metadata

Field	Value
Publication number	US-10589469-B2
Application number	US-201615281351-A
Country	US
Kind code	B2
Filing date	Sep 30, 2016
Priority date	Oct 5, 2015
Publication date	Mar 17, 2020
Grant date	Mar 17, 2020

Abstract

A welded joint between at least one metal material element and at least one thermoplastic material element is obtained by pressing the elements against each other while applying heat. Contact surfaces of the metal material, which are in contact with the thermoplastic material, are provided with uneven surface portions having a distribution of asperities. With heat applied, the thermoplastic material fills spaces between these asperities and maintains this configuration after subsequent cooling, thereby improving strength of the joint. The uneven surface portions are obtained in a preliminary forming step of the metal material in a press mold, which is configured with a forming surface for generating the uneven surface portions by mechanical deformation and/or with a device for guiding a laser or electron beam. By this technique, hybrid components are obtained made of one or more elements of metal material between which a shaped component of thermoplastic material is interposed.

First claim

What is claimed is:

1. A method for obtaining a welded joint between elements of different materials, wherein the welded joint comprises at least one element of metal material and at least one element of thermoplastic material having respective contact surfaces, wherein said contact surfaces of said at least one element of metal material and said at least one element of thermoplastic material are pressed against each other with simultaneous application of heat, wherein the contact surface of said at least one metal element has at least one uneven surface portion, wherein said at least one uneven surface portion has a distribution of asperities, wherein said application of heat is such as to generate a softening of the thermoplastic material, so that said thermoplastic material fills spaces between the asperities of said uneven surface portion and maintains this configuration after a subsequent cooling,
wherein said at least one element of metal material is a shaped component of a sheet metal element, which is obtained in a preliminary shaping step by mechanical deformation in a press mould, and
wherein said at least one uneven surface portion is obtained by mechanical deformation in said press mould during said preliminary forming step for shaping said at least one element of metal material in said press mould.

2. The method according to claim 1 , wherein said mould is provided with a forming surface adapted to create said at least one uneven surface portion by a mechanical deformation of the metal material when said at least one element of metal material is deformed within said mould.

3. The method according to claim 2 , wherein said forming surface of the press mould is provided directly on one element of the press mould.

4. The method according to claim 2 , wherein said forming surface is provided on an insert which is associated to a press mould element.

5. The method according to claim 2 , wherein said asperities of said at least one uneven surface portion, which is obtained by a mechanical deformation, have height and width values between a minimum value in the order of manometers and a maximum value in the order of millimeters.

6. The method according to claim 1 , wherein said mould is provided with a device for guiding and addressing a laser beam or an electron beam adapted to generate said at least one uneven surface portion of the at least one element of metal material by evaporation and subsequent solidification of the metal material, when the at least one element of metal material is located within the mould.

7. The method according to claim 6 , wherein said asperities of said at least one uneven surface portion, which is obtained by a laser beam or an electron beam, have height and width values between a minimum value in the order of manometers and a maximum value in the order of micrometers.

8. The method according to claim 1 , wherein said mould is provided with a forming surface adapted to create said at least one uneven surface portion by a mechanical deformation of the metal material when said at least one element of metal material is deformed within said mould and wherein said mould is also provided with a device for guiding and addressing a laser beam or an electron beam adapted to generate secondary irregularities on said at least one uneven surface portion which is obtained by mechanical deformation.

9. The method according to claim 1 , wherein said at least one uneven surface portion is formed only on one face of said sheet metal element which is provided for coming in contact with said at least one element of thermoplastic material.

10. The method according to claim 1 , wherein said at least one uneven surface portion is formed on both faces of said sheet metal element, as a result of a mechanical deformation of said sheet metal element in said mould.

11. The method according to claim 10 , wherein the mechanical deformation of said sheet metal element in said mould confers an undulated shape with a substantially uniform thickness to the sheet metal element.

12. The method according to claim 11 , wherein a height of the asperities of said at least one uneven surface portion, which is obtained by mechanical deformation of said sheet metal element, is substantially similar to a thickness of the sheet metal element.

13. The method according to claim 1 , wherein said application of heat is obtained by a laser beam.

14. The method according to claim 13 , wherein said laser beam is emitted by a laser head carried by a multi axis manipulating robot.

15. The method according to claim 13 , wherein the laser beam is directed against a surface of said at least one element of metal material located on a side opposite with respect to said contact surface.

16. The method according to claim 1 , wherein said welded joint comprises two elements of different metal materials with the at least one element of thermoplastic material interposed therebetween; the contact surface of each of said two elements of different metal materials facing towards said interposed element of thermoplastic material being provided with one or more uneven surface portions obtained in the preliminary forming step of said two elements of different metal materials in respective moulds.

17. The method according to claim 1 , wherein said thermoplastic material is a composite material including a thermoplastic matrix reinforced with fibres.

18. A hybrid component, comprising an element of metal sheet and a panel of thermoplastic material having respective flanges connected to each other by the method according to claim 1 .

19. A hybrid component according to claim 18 , wherein said thermoplastic material is a composite material with a thermoplastic matrix reinforced with fibres.

20. A hybrid component, comprising two elements of metal sheet and a panel of thermoplastic material interposed between said elements of metal sheet, each element of metal sheet being connected to said panel of thermoplastic material by the method according to claim 1 .

21. A hybrid component made of two elements of different metal materials connected to each other with the interposition of one or more portions of thermoplastic material, wherein each element of metal material is joined to a respective portion of thermoplastic material by the method according to claim 1 .

Assignees

• Fiat Ricerche

Inventors

• Pullini Daniele

Classifications

• B29C66/543

  joining more than two hollow-preforms to form said hollow articles · CPC title

• B29C66/022

  Mechanical pre-treatments, e.g. reshaping · CPC title

• F16B5/08

  by means of welds or the like (welding B23K) · CPC title

• B29C66/7422

  Aluminium or alloys of aluminium · CPC title

• B29C66/0222

  without removal of material, e.g. cleaning by air blowing or using brushes · CPC title