FR2783196A1 - Foamed plastic part with an externally accessible insert, e.g. an automobile panel with an inserted electrical or mechanical component, is made by molding the core about the protectively covered insert and machining to access the insert - Google Patents

Abstract

Production of a surface fiber-reinforced foamed plastic part (1) with an externally accessible insert (6, 7), by molding the core about the protectively covered insert (6, 7) and machining the finished part to access the insert, is new. A surface fiber-reinforced foamed plastic part (1) with an externally accessible insert (6, 7) is produced by: (a) covering the insert (6, 7) with a protective element (8, 9) within a first mold cavity; (b) foaming the core (2) in the first mold; (c) covering the core with one or more fiber sheets and placing it in a second mold for injection of a plastic material such as a resin to impregnate and cover the fiber sheet; and (d) machining the external wall of the part and the protective element to access the insert.

Description

The invention relates to a method of manufacturing a piece of ma-

  plastic with a foam core, a reinforced outer wall

  by glass fibers and an element inserted in the room.

  For the manufacture of motor vehicles of the future, of simplified design, it is envisaged to produce the entire hull or coach-

  made from very rigid plastic structural elements

  easy to assemble, and presenting a surface appearance without

  must and can be used possibly without protective or appearance paint. Such structural elements, which may for example be in the form of panels, the surfaces of which have recessed portions and raised portions, comprise a foam core of material.

  plastic giving very good sound and thermal insulation properties

structural elements.

  Such insulating panels can also be used in the

  in the building sector, or in the construction of pleasure boats

  sance. The foam core is covered on opposite sides by plastic walls reinforced with fibers, these walls having the

  forms external surfaces of the part. These parts are generally made

  briquetted by a resin transfer molding process or process

  RTM (from the English name Resin Transfer Molding).

  In such a process, the foam core is produced by injection and foaming of a plastic material in a mold, then the foam core

  is coated on both sides with reinforcing plies consisting mainly of

  payment by glass fibers. These sheets, mainly made of glass fibers, are generally preformed to closely match the

  external shape of the surfaces of the foam core.

  The foam core covered by the layers of fibers is introduced

  in a second mold in which the injection of a plastic material is carried out

  as a resin, so as to completely impregnate and cover the

fiber sheets.

  After curing and hardening of the resin, the finished part is demou-

  lée. To obtain parts with a perfect surface appearance without the need to paint them, it is possible to deposit a coating substance called gel coat on the surfaces of the second mold, before

  place the foam core covered by the glass fiber sheets.

  In many cases it is necessary to insert elements such

  that electrical conductors or mechanical connection devices

  ques, in the foam core of the room and possibly in the reinforced wall. These inserted elements must be accessible on a surface

external part.

  For example, in the case of the manufacture of structural elements of motor vehicles, it is necessary to pass conductors

  such as wires or cables to supply electric current

  than different parts of the motor vehicle. These electrical conductors are connected, at at least one of their ends, to a connector or to a component of the equipment of the motor vehicle such as an optical support. It may also be necessary to insert inside the structural elements fixing or mechanical connection parts

  only screws or nuts or even ventilation ducts.

  The use of elements inserted inside the foam core and / or of the reinforcement layer of the parts makes it possible to reduce the time of assembly and assembly of these parts, to improve the aesthetics of the parts and assemblies in which they are mounted because the insert is partially or totally embedded in the material of the part and to avoid

  noises when using the device constituted by assembling the parts

  these, from the fact that the elements are housed in the material and in particular

  in the foam core of the part.

  However, the manufacture by the RTM process of parts comprising a foam core covered by walls reinforced with glass fibers is difficult to adapt to the case of parts comprising inserted elements such as electrical conductors connected to electrical connectors or components or mechanical fixing inserts or

ventilation ducts.

  The object of the invention is therefore to propose a manufacturing process

  of a plastic part comprising a foam core of ma-

  plastic, at least one outer wall reinforced with coated fibers

  with a core surface and an insert accessible on an external surface of the part, in which the core is produced by molding a pre-

  plastic material in a cavity of a first mold, with foam

  wise of the plastic material, the core is covered with at least one ply comprising fibers, the core covered with the ply of fibers is placed in a second mold and a second plastic material is injected, such

  than a resin, in the sheet of fibers, so as to impregnate and re-

  cover, characterized in that the element to be inserted is placed in the cavity of the first mold and that at least part of this element to be inserted is isolated

  of the cavity of the first mold by a protective element, before the

  lage of the first plastic material, that the second plastic material is injected into the sheet of fibers covering the insert and the protective element and that at least part of the external wall of the part is machined

  and the protective element to access the inserted element.

  In order to clearly understand the invention, we will now describe, by way of examples, several modes of implementing the following method

  the invention, for the production of parts having an inserted element.

  Figures 1A, 1B and 1C are sectional views showing ma-

  nier schematic three phases of a process for producing a part comprising an inserted element constituted by an electrical conductor connected to

a connector of a first type.

  FIGS. 2A, 2B and 2C are schematic cross-sectional views

  trant three phases of carrying out a method of manufacturing a part comprising an inserted element constituted by an electrical conductor connected to

a connector of a second type.

  Figures 3A, 3B, 3C and 3D are sectional views showing that

  three phases of a process for manufacturing a part comprising an element

  inserted consisting of an optical support.

  FIGS. 4A, 4B and 4C are sectional views showing, from my

  schematic, two phases of a part manufacturing process

  comprising an inserted element constituted by a mechanical fixing element

than.

  Figure 5 is a sectional view showing the assembly of two parts

  these produced by the method according to FIGS. 1 A, 1 B and 1 C. In the case of structural elements of a motor vehicle, it is necessary to insert, in at least certain structural elements, components constituted by electrical conductors such as wires or

  cables which are connected at one end to an electrical connector

  stick. The electrical connector must be accessible on an external surface

of the structural element.

  A structural element has been produced as shown in FIG. 1C, generally designated by the reference 1 and comprising a foam core 2, reinforced external walls 3a and 3b and an electrical element.

  inserted 4, by the RTM process implemented according to the invention.

  First, as shown in FIG. 1A, we dis-

  laying, in a cavity of a first mold, designated by the reference 5 and com-

  carrying a first mold part 5a and a second mold part 5b

  delimiting between them the mold cavity, an assembly constituted by a con

  conductor such as an electric wire 6, a connector 7 connected to one of the ends

  electrical wire 6 and a plastic casing 8 containing the connector

  tor 7 closed by a plastic cover 9.

  The wall of the housing 8 has an opening in which one intro

  duit the wire 6 which is connected to the connector 7 inside the housing. After not-

  wise wire in the opening, we seal between the wire 6 and the wall of the

  housing 8 by depositing an elastomer such as polyurethane. It is also

  It is possible to pass the wire 6 inside an attached single-joint

in the wall of the housing 8.

  The closure cover 9 of the housing is attached and glued or screwed

  on the opening of the housing through which the connector 7 has been introduced.

  The wall 5b of the mold 5 has a part 5'b projecting towards

  the interior of the cavity on which a cavity of cor- rect shape engages

  corresponding delimited by a protruding rim of the cover 9 of the housing 8.

  This produces perfect indexing and positioning of the housing 9 and the

  connector 7 immobilized inside the housing 8, in the mold cavity 5.

  We inject and foam a plastic material such as

  polyurethane inside the mold.

  There is thus obtained, after hardening of the polyurethane foam, a core into which the electrical wire 6 and the connector 7 are inserted,

  the interior of the plastic casing 8.

  The outer surfaces of the foam core, which have

  any, according to the use of the part 1 to be produced, are covered, as it can be seen in FIG. 1 B, by two layers 1 1 a and 1 1 b made up

  mainly by glass fibers and generally preformed. This en-

  seems to be placed inside the cavity of a mold 10 having two parts 10a and 10Ob delimiting the cavity of the mold. A plastic, which is generally a resin, is injected into the mold, so that the liquid resin injected under pressure permeates and completely covers the sheets of glass fibers 11a and 11b. After cooking and hardening of the

  resin inside the mold, the reinforced walls 3a and 3b are obtained

the foam core 2.

  Part of the ply 11b covering the cover 9 of the housing 8 containing the connector 7 is housed inside a cavity formed in the foam core, during its molding, due to the presence of the

  projecting part 5'b of part 5b of the first mold. The corresponding part

  dante of the wall 3a of the part 1 is cut and removed, then the part of the cover 9 of the housing 8 located in the bottom of the cavity of the foam core is also machined and removed, so that the movable contactor 12 of the connector 7, recalled by a spring towards the outside of the connector, which was held by the cover 9 in the retracted position, moves in the direction of extraction to come slightly protruding relative to the surface

  external of the wall 3a of the part 1. The active part of the connector, that is to say

  say the mobile contactor 12, is therefore easily accessible on one of the

faces of the part 1.

  The method according to the invention therefore makes it possible to easily and very precisely carry out the insertion of an insert inside a part produced by the RTM process comprising a foam core and walls

  reinforced with glass fibers.

  During the molding of the foam core and during the injection of the resin into the layers of glass fibers, the sensitive part of the inserted element, that is to say the connector 7, is perfectly protected by the housing 8

  tightly closed by the cover 9 glued to the edges of its or

  so that plastic cannot come into contact with the

  connector. The cover 9 of the housing 8 is moreover adjusted in such a way

  negates that the connector 7 is perfectly maintained inside the housing,

  then, after molding inside the foam core, by coating the box

  tier in plastic foam.

  The seal 13 produced around the passage of the electric wire 6 through

  towards the wall of the housing 8 also makes it possible to avoid any introduction of

  plastic material in the housing containing the connector.

  During the injection of the resin under pressure into the second mold, the connector is also perfectly protected by the waterproof housing.

liquid resin under pressure.

  The method according to the invention therefore makes it possible to adapt the method of

  RTM molding to production on an industrial scale of parts comprising

  both a foam core, reinforced walls and at least one embedded insert

in the foam core.

  In FIGS. 2A, 2B and 2C, an alternative embodiment is shown.

  tion of the method, in the case of an electrical conductor 6 ′, such as an electric wire

  plug connected to a 7 'connector made in the form of a male plug

  carrying pins intended to come and engage in openings of a

female connector.

  The corresponding elements in FIGS. 2A, 2B, 2C on the one hand and

  1 A, 1 B, 1 C on the other hand have the same references.

  When the 7 'connector is placed inside the box,

  tier 8 closed by the cover 9, a sufficient length of the section is provided

  tie 6'a of the conductor 6 'between the sealed passage 13 through the wall of the housing 8 and the end of the electrical conductor connected to the connector 7', so that the connector 7 'can be removed from the housing 8 by the opening of the reinforced wall 3a produced, as before, by cutting a part of this wall followed by cutting by machining the cover 9 of the housing 8. The connector 7 'is thus accessible from the side of the wall 3a of the part 1' to make a connection with the female connector into which the male connector 7 'can be inserted.

  Of course, the female connector in which the connector is engaged

  male connector 7 'can also be associated with a part manufactured by the

method according to the invention.

  All the steps in the manufacturing process of the part 1 'represent

  tees in Figure 2C are identical to the manufacturing steps of part 1

  represented in FIG. 1C, as it can be seen in the figures, 2A my-

  trant the foam core at the end of molding in a first mold, 2B showing the foam core in which the insert is coated, which is surrounded by sheets of fibers and placed in a second mold for the injection of a

  resin in the layers of fibers and 2C showing the finished part after uncovering

  page of part of the wall 3a and of the cover 9 of the housing 8.

  In FIGS. 3A, 3B, 3C and 3D, various stages of a method according to the invention are shown for the manufacture of a part 14 such as

shown in Figure 3D.

  The part 14 is a shaped part constituting a structural element

  of a motor vehicle. Part 14 includes a foam core

  and an outer wall 16 reinforced with glass fibers. In a case

  vity 17 of the foam core 15 is fixed an insert 18 constituting an optical support of the motor vehicle allowing the fixing and the supply of electric current by means of an electric wire 20, bulbs 19 and 19 '. As can be seen in FIG. 3A, in order to integrate the insert 18 into the foam core 15 of the part 14, place inside the cavity of a mold delimited by a part of the mold 21 , a plastic case 22 closed by a cover 23, of rounded shape, fixed by gluing

  on the open end of the housing 22.

  The mold wall 21 has a part 21 'projecting towards the inside of the cavity and the cover 23 of the housing has an edge slightly projecting on its external surface along a contour corresponding to the contour.

  of the part 21 'projecting from the wall of the mold. We thus realize a position-

  precise housing 22 inside the mold cavity 21.

  The bulb holder 24 of the insert 18, which can for example be a metal element or a plastic element in which are engaged lampholders 19 and 19 ′ connected to the conductor, is fixed by at least one screw 25 in the bottom of the housing 22. The fixing of the

  support 24 in the bottom of the housing 22 is of course carried out before closing

  meture of the housing by the cover 23 glued following the opening of the housing.

  When the insert 18 has been placed in the mold cavity,

  reads the injection of a plastic material such as polyurethane into the

  mold cavity and foaming of this plastic. The plas-

  tick injected in the form of foam cannot penetrate inside the housing 22 which is sealed by the cover 23 and because

  The opening for passage of the wire 20 is closed by a plastic material

  tomère such as polyurethane forming a joint 26 or even by a joint

  single-line previously introduced into an opening in the housing 22.

  As can be seen in FIG. 3B, the foam core 15 in

  which is coated the insert 18 is covered with a preformed sheet 28 cons-

  mainly made of glass fibers and placed in the cavity of a mold 27

  in which the injection of a liquid resin under pressure is carried out to

  preg and cover the sheet of glass fibers 28 placed around the core 15. A part 28a of the fiber sheet 28 which covers part of the cover of the housing 22 is housed in the part of the cavity of the core 15 in which is disposed the insert 18, this entry part of the cavity being obtained due to the presence of the projecting part 21 ′ of the wall of the mold

21 for molding the core 15.

  After injecting the resin into the sheet of glass fibers 28 and baking the resin, the part obtained is removed from the mold, which comprises the foam core 15 surrounded by the wall 16 of resin reinforced with glass fibers.

  As can be seen in FIG. 3C, part of the wall 16 comprises

  carrying part 28a of the sheet of glass fibers located at the entrance to the

  cavity 17 of the foam core, part of the core 15 and part of the neck

  23 of the housing 22 are cut so as to give access to the interior of the cavity containing the bulb holder 24.

  It is possible to widen the opening so as to clear the upper

  port of bulbs 24, as can be seen in FIG. 3C.

  We can then, as shown in Figure 10, set up

  the bulbs 19 and 19 'in the corresponding sockets connected to the con-

  supply duct 20, then the window 29 which can be glued with a gasket

  glue 29 ′ on the external surface of the reinforced wall 16.

  The method according to the invention therefore makes it possible to produce a complex part containing an electrical component of a motor vehicle. through

  simple RTM molding operations.

  The method according to the invention, as will be explained with reference to FIGS. 4A, 4B and 4C, also makes it possible to manufacture a part having an inserted element having a mechanical function instead of an electrical function. As can be seen in FIG. 4C, the part 31 comprises a foam core 30, reinforced walls 32a and 32b and a mechanical element

  33 partially inserted in the foam core 30 and in the reinforced wall

cée 32a.

  The inserted element 33, which can be made of metal, comprises an internally threaded tubular barrel embedded in the core 30, over most of its length and a circular support plate surrounding the tubular part partially inserted in the reinforcing layer 32a. The insert 33 can be used to fix an element on the part 31 by means of a rod

  threaded and a nut resting on the flat plate of insert 33. The metal insert

  lique 33 can also be used to assemble the part

  31 to a second part also comprising a threaded insert, via the

medial of a threaded rod.

  As can be seen in FIG. 5A, in a first step of the

  manufacturing process of the part 31, insert the insert 33, the barrel of which

  threaded bular is closed by one or two closing plugs 34 and 34 ',

  in a cavity of the internal wall of a part 35a of a mold 35 comprising

  carrying two parts 35a and 35b between which is formed a cavity.

  The core 30 is made of polyurethane foam in which the threaded tubular barrel of the insert 33 is embedded. After removing the core from the mold, the flat plate is slightly released

  to support the insert 33 of the foam of the core 30, by elimination of a material

  filling line, and the core 30 is surrounded by two layers 36a and 36b consisting mainly of glass fibers. The support plate of

  the insert is inserted between the fibers of the web 36a.

  The assembly constituted by the core in which the inserted element is fixed

  re 33 and the layers 36a and 36b of glass fibers is introduced between two

  parts 37a and 37b of a second mold 37.

  A resin is injected into the mold 37, so as to

  preg and cover the layers of glass fibers 36a and 36b.

  After baking the resin, the part is removed from the mold and, as shown

  felt in FIG. 5C, part of the reinforced wall 32 covering the tubular barrel of the insert 33 is removed by machining.

  also by machining the plug 34 closing the inlet of the tarau-

from the barrel of the insert.

  This tapped opening and then accessible on the outer surface

of the wall 32a of the part 31.

  The method of manufacturing the part comprising an inserted element 33 having a mechanical function has the same advantages as the method of manufacturing a part comprising an inserted element having a

  electrical function, as described above.

  In FIG. 6, an assembly and connection zone has been shown.

  electrical connection between two panels 1a and 1b, of complementary shape, the panels 1a and 1b having been produced by a method according to the invention such

  as shown in FIGS. 1A, 1B and 1C and described with reference to these figures

  res. The panels 1a and 1b are assembled by interlocking their parts

  end ties one inside the other and fixing of these end parts by

glue joints 38 and 38 '.

  Inside the foam core of the part 11a, a connector is inserted.

  electrical conductor 6a and a connector 7a disposed inside a housing

inserted into the foam core.

  The connector 7a is connected to the end of the electrical conductor 6a and comprises a contactor 12a returned by spring towards the outside of the panel 1a, so as to be slightly projecting with respect to the face of the

  panel attached to a face of the 1lb panel which itself

  even a connector 7b opposite the connector 7a. The contactor 12b of the connector 7b comes into contact through its end part with the end of the contactor 12a of the connector 7a, so that the contactors 12a and 12b pushed outwards by springs come into contact with one another. other with a certain pressure, which ensures the passage of the electric current from the conductor 6a to the conductor 6b connected to the connector 7b, by

  through connectors 7a and 7b, which are actuated due to the displacement

  cementing of contactors 12a and 12b inward.

  This ensures simultaneous assembly of two panels and the electrical connection of the electrical elements inserted inside these

two panels.

  The process according to the invention therefore allows parts to be obtained

  carrying a foam core, at least one external wall reinforced by fibers and an inserted element, by an RTM process which can be implemented

  very easily in the context of industrial manufacturing.

  It is understood that the method according to the invention is not limited

  to the embodiments which have been described.

  It is possible to envisage the production of parts comprising inserted elements of any type, whether these elements are inserted entirely in the foam core or both in the foam core and in the

reinforced wall of the room.

  The parts produced by the process according to the invention can be

  made from various plastics and natural fibers

  which are chosen in such a way as to ensure desired properties for the

piece produced.

  The invention applies not only in the context of the industry

  tomobile but also in the context of other industries such as prefab

  cation for the building or construction of pleasure boats.

Claims (10)

  1.- Method of manufacturing a part (1, 1 ', 14, 31) in plas-   tick comprising a foam core (2, 15, 30), at least one wall ex-   dull (3a, 3b, 16, 32a, 32b) reinforced by fibers covering a surface of the core (2, 15, 30) and an element (6, 6 ', 7, 7', 18, 33) inserted in the part and accessible on an external surface of the part, in which the core (2, 15, 30) is produced by molding a first plastic material in a   cavity of a first mold (5a, 5b, 21, 35a, 35b) with foaming of the ma-   plastic, the core (2, 15, 30) is covered with at least one ply (1a, 11b, 28, 36a, 36b) comprising fibers, the core (2, 15, 30) is covered with the sheet of fibers (11a, 11b, 16, 36a, 36b) in a second mold (10a, 10b, 27, 37a, 37b) and a second plastic material is injected   such as a resin in the fiber web (11a, 11b, 16, 36a, 36b) of ma-   deny to impregnate and cover it, characterized in that the element to be inserted (6, 6 ', 7, 7', 18, 33) is placed in the cavity of the first mold (5a, b, 21 , 35a, 35b) and that at least part of the element to be inserted (6, 6 ', 7, 7', 18, 33) is isolated from the cavity of the first mold (5a, 5b, 21, 35a, 35b) by   a protective element (8, 9, 22, 23, 34, 34 ') before molding the pre-   first plastic material, that the second plastic material is injected   tick in the sheet of fibers (1 la, 11 b, 16, 36a, 36b) covering the element to be inserted (6, 6 ', 7, 7', 18, 33) and the protective element (8, 9 , 22, 23, 34, 34 ') and that at least part of the external wall (3a, 3b, 28, 32a, 32b) of the part and of the protective element (8, 9, 22 , 23, 34, 34 ') to access   the inserted element (6, 6 ', 7, 7', 18, 33).   2.- Method according to claim 1, characterized in that the protective element (8, 9, 22, 23) is a housing in which there is, prior to the molding of the core, at least one part (7, 7 ', 24) of the element to be inserted, the housing (8, 9, 22, 23) then being closed so sealed by a cover (9, 23).   3.- Method according to claim 2, characterized in that the   housing (8, 9, 22, 23) is made of plastic and the closing cover   frame (9, 23) of the housing is tightly fixed, by gluing to the housing (8, 22).   4.- Method according to any one of claims 2 and 3, in   the case where the inserted element (6, 7, 6 ', 7', 20, 24) is an electrical conductor connected to an electrical component (7, 7 ', 24) placed in the housing, characterized   by the fact that the electrical conductor (6, 6 ', 20) passes through a wall of the box   tier (8, 22) inside an opening in the wall of the housing, the passage being sealed against a liquid plastic material, by an element sealing (13, 26).   5.- Method according to claim 4, characterized in that the electrical component is an electrical connector (7, 7 ') disposed in the housing (8) and that part of the wall (3a) of the part is cut out. (1) and the cover (9) of the housing (8) to allow passage to the outside of the   part (1), of an electrical contactor (12) of the connector (7).   6.- Method according to claim 5, characterized in that the electrical component (7 ') is a plug-in electrical connector (7') and   that a part of the external wall (3a) of the part (1 ′) and of the neck are cut   ring (9) of the housing (8) to allow passage to the outside of the part   (1 '), of the connector (7') as a whole.   7.- Method according to claim 5, characterized in that the electrical component (24) is an optical support intended to receive at   minus a light bulb (19, 19 '), characterized in that the sup-   optical port (24) is fixed to a wall of the housing (22), so that the housing (22) forms part of the optical support and that part of the part (14) and of the cover (23) of the housing (22) for releasing the support (22, 24) of the light bulbs (19, 19 '), a transparent protective wall (29) then being fixed on the external wall (16) of the part (14) according to an opening cut in the part (14) giving access to the optical support (22, 24) disposed in a cavity of the foam core (15) of the part (14).   8.- Method according to any one of claims 1 to 3, in   the case where the inserted element is a mechanical fixing element (33), charac-   terrified by the fact that the mechanical fixing element (33) is partially fixed-   inside the foam core (30) of the part (31) and partially   in an external wall (32a) of the part (31).   9.- Method according to claim 8, characterized in that   the mechanical fastening element (33) is an internal threaded tubular element   laughing and that the protective element (34, 34 ') of the mechanical fixing element is constituted by at least one plug (34, 34') closing the internal threaded bore of the mechanical fixing part (33). 10. Process according to claim 5, characterized in that the assembly of a first part (la) is carried out in which is inserted a first electrical conductor (6a) connected at its end to an electrical connector (7a) comprising an electrical contactor (12a) and a second part (lb) comprising a second electrical conductor (6b) inserted in the second part (lb) and connected at its end to a connector (7b) comprising a contactor (12b), the contactors ( 12a, 12b) projecting from one side   external of the first part (la) and the second part (lb), respectively-   ment, and that the part (la) and the part (lb) are assembled and fixed to each other, so that the electrical contactors (12a, 12b) come into contact with one another. other and provide electrical contact by   through the connectors (7a, 7b), between the first electrical conductor   as (6a) and the second electrical conductor (6b).