GB2558611A

GB2558611A - A method of joining first and second components, a component assembly formed by the method and an insert for use in the component assembly

Info

Publication number: GB2558611A
Application number: GB1700385.6A
Authority: GB
Inventors: Fahy Trevor
Original assignee: Penn Engineering Fastening Tech Europe Ltd
Current assignee: Penn Engineering Fastening Tech Europe Ltd
Priority date: 2017-01-10
Filing date: 2017-01-10
Publication date: 2018-07-18
Also published as: GB201700385D0

Abstract

A method of joining first 10 and second 12 components not readily weldable together comprises introducing an insert 14 into the first component which is of a material weldable to the second component to secure the first and second components together. Alternatively a second insert (38, Figure 3) may be introduced into the second component 12 and welded to the first insert. The first and second inserts can transmit loads to their respective components such as by a contact surface 20 located between a head 16 and a shaft 18.The inserts may be metal or plastics. A deposit of braze or solder (50, Figure 5) may be applied to the end of the first insert to aid welding. The first and second components may comprise panels and intermediate panels may be provided between them. The first or second insert may comprise an internal or external thread. A protrusion or chamfer may be provided at the end of an insert to act as a weld start point and allow shrinkage and resulting compression after solidification of the weld pool. May be used in the automotive industry and for metal to metal, composite to metal or composite to composite joins.

Description

(71) Applicant(s):

Penn Engineering Fastening Technologies (Europe) Ltd.

Mervue Business Park, Galway, Ireland (72) Inventor(s):

Trevor Fahy

(51) INT CL:
B29C 65/64 (2006.01) B23K 11/20 (2006.01)	B23K 11/00 (2006.01)
(56) Documents Cited: EP 0967044 A1	EP 0718068 A1
CA 002029814 A	DE 029718724 U
DE 003210310 A	US 20150099084 A1
US 20130309520 A1	US 20050161442 A1
(58) Field of Search: INT CL B29C Other: WPI, EPODOC

(74) Agent and/or Address for Service:

Manitz Finsterwald Patentanwalte PartmbB Postfach 31 02 20, D-80102, Munchen, Germany (54) Title of the Invention: A method of joining first and second components, a component assembly formed by the method and an insert for use in the component assembly Abstract Title: Weldable insert for joining components (57) A method of joining first 10 and second 12 components not readily weldable together comprises introducing an insert 14 into the first component which is of a material weldable to the second component to secure the first and second components together. Alternatively a second insert (38, Figure 3) may be introduced into the second component 12 and welded to the first insert. The first and second inserts can transmit loads to their respective components such as by a contact surface 20 located between a head 16 and a shaft 18.The inserts may be metal or plastics. A deposit of braze or solder (50, Figure 5) may be applied to the end of the first insert to aid welding. The first and second components may comprise panels and intermediate panels may be provided between them. The first or second insert may comprise an internal or external thread. A protrusion or chamfer may be provided at the end of an insert to act as a weld start point and allow shrinkage and resulting compression after solidification of the weld pool. May be used in the automotive industry and for metal to metal, composite to metal or composite to composite joins.

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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A method of joining first and second components, a component assembly formed by the method and an insert for use in the component assembly

The present invention relates to a method of joining first and second components of which the first component is of a material not readily weldable to the second component, to a component assembly made by the method and to an insert for use in the method.

In the world of multi-material assembly there is a challenge to attach new lightweight materials such as composite materials and aluminium to steel and to join composite materials to metals in general or to each other. Composite materials will be understood to comprise fibre reinforced plastics or fabric reinforced plastics such as glass fibre reinforced resins or carbon fibre or plastic reinforced resins. The resins can be thermoplastics such as polyamides, or thermosetting resins such as polyester or epoxy resins. There are a wide variety of reinforcing fibres and fabrics made from such fibres and also a very wide range of resins which can be considered as a matrix material for the fibres or fabrics. It is possible to weld aluminium to steel by special processes such as friction butt welding or explosion welding but these are complicated techniques and are not readily adapted to materials in component form. Aluminium is in any event a challenging material to weld and not all aluminium alloys can be welded, not even to other aluminium alloys. Similar problems can exist with magnesium alloys. Composite materials with thermosetting matrixes cannot be welded at all.

The object underlying the present invention is to provide a generally applicable method of joining materials which are not readily weldable to one another or can only be welded to one another with difficulty. The invention is particularly concerned with joining first and second components of material but the term component” is to be widely understood, it can, for example and without any intended restriction, include a first material in the form of a foot or flange of a component or housing, with the need arising to join the component or housing to a second material of component form. Again the term second material of component form is to be interpreted widely as indicated above.

One preferred type of component to which the present invention relates is a panel. The method should be capable of extension to joining first and second panels or components to one another. The method can also be further extended to joining first and second panels or components with at least one first intermediate panel and optionally at least one further intermediate panel disposed between the first and second panels or components.

It is also an object of the present invention to provide a joint which is not materially thicker than the two or more panels or components being joined.

In order to satisfy these objects the present invention provides a method of the initially named kind, wherein a first insert of a material which can be joined by fusion to the second component, or to a second insert provided in the second component and formed to transmit loads to the second component, is inserted into the first component and is formed to transmit loads to the first component, and wherein the first insert is subsequently joined by fusion to the second component or to a said second insert provided in the second component.

The idea here is to locally add the parent weldable material, e.g. an insert of steel into components that cannot normally be easily spot-welded. The insert may have a pointed or chamfered end that protrudes slightly from the opposite side of the component. This protrusion ensures good alignment and ease of insertion, good metal to metal pressure, acts as an electrical concentration point for heating and provides extra material to form the weld pool. After the weld is complete and the weld pool has solidified the head of the insert will hold the component or component assembly together, preferably with a certain preload or clamping pressure which can be determined by the degree of axial shrinkage which takes place during welding.

The method of the invention is very flexible, for example a first insert of steel can be used to secure an aluminium component or panel to a steel component or panel. It can also be used to join a composite component or panel to a steel component or panel. It could also be used to secure a first aluminium component to a second aluminium component if a second steel insert is provided in the second aluminium component. Any desired number of intermediate panels of any desired materials can be used.

Alternatively a first insert of a weldable aluminium alloy can be used to join a first component or component of a composite material to a second component of composite material having a second insert of a weldable aluminium alloy, i.e. weldable to the first insert. Again any desired number of intermediate components of any desired materials can be provided.

The invention is also not limited to metal inserts, for example a first insert of a suitable ultrasonically weldable plastic can be inserted in a component or panel of thermosetting plastic and can be used to join that component or panel by ultrasonic welding to a second component or panel of ultrasonically weldable plastic material, or to a second insert of ultrasonically weldable plastic material provided in a component or panel of a plastic composite. Equally such ultrasonically weldabe plastic inserts can be used to join metal components or components to one another or to composite materials with a plastic matrix. The use of such ultrasonically weldable plastic inserts can be a useful technique to reduce the heat input into the component or component assembly.

If heat input is a concern, another way of overcoming this is to provide a deposit of a brazing or soldering material at an end of the first insert which then allows the first insert, and thus the first component to which it is connected, to be joined to the second component or to an insert provided in the second component.

One foreseeable and very desirable application for the invention is in the automotive industry where lines set-up for spot-welding already exist and can be used to aid manufacturers looking for ways to substitute other materials in their production processes but to keep the general layout of the production process the same.

Preferred embodiments of the invention can be summarized as follows:

In accordance with one preferred embodiment of the method the step of joining the first insert to the second component or to a said second insert by fusion is performed by one of spot welding, induction welding, by explosive welding, by capacitor discharge welding, by laser welding, by ultrasonic welding, or by brazing or soldering. These are all well-known fusion techniques which can be considered for the realization of the invention.

When the first insert comprises a metallic material it can, for example, be joined to the second component, or to a second insert provided in the second component, by spot welding, by induction welding, by explosive welding or by capacitor discharge welding.

Alternatively the first insert can be provided at an end adjacent the second component with a deposit of braze material or solder material and can be joined by brazing or by soldering to the second component, or to a second insert provided in the second component, by the introduction of heat energy by spot welding, by induction, by explosion, by capacitor discharge or by ultrasound. The use of a braze material or a solder material can be used to reduce the heat input to the component assembly.

In another embodiment the first insert comprises a material capable of being ultrasonically welded to the second component, or to a second insert provided in the second component, and is joined to the second component or to a second insert provided in the second component by ultrasonic welding. Such inserts can for example be made of plastic materials such as polyamide. Use of this class of inserts provides another way of further reducing the heat input to the component assembly.

The first insert is generally inserted into the first component so that it extends from a first side of the first component to a second side of the first component adjacent the second component or adjacent to an end of a second insert provided in the second component.

At least one intermediate panel can be provided between the first component and the second component wherein the first insert is inserted into the first component and the at least one intermediate panel so that it extends from a first side of the first component remote from the at least one intermediate panel to a side of an intermediate panel adjacent the second component, or adjacent to an end of a second insert provided in the second component.

Alternatively, at least one intermediate panel can be provided between the first component and the second component, wherein the first insert is inserted into the first component and extends from a first side of the first component remote from the at least one intermediate panel to a second side of the first component adjacent the intermediate panel and wherein a second insert is provided in the second component and in the at least one intermediate panel and extends from a side of the second component remote from the at least one intermediate panel through the second component and the at least one intermediate panel to a position adjacent the first insert

The invention also contemplates a method wherein at least one first intermediate panel is provided adjacent the first component and at least one further intermediate panel is provided adjacent the second component and adjacent the at least one first intermediate panel, wherein the first insert is inserted into the first component and extends from a first side of the first component remote through the first component and the at least one first intermediate panel to a position adjacent an end of a second insert provided in the second component and extending from a side of the second component remote from the at least one further intermediate panel through the second component and through the at least one further intermediate panel.

Thus in this embodiment the first insert extends through the first component and any or all first intermediate components that are present and the second insert extend through the second component and any or all further intermediate components that are present.

In general it is preferred for the first insert to have a head portion and a shaft portion, the head portion being of a larger cross-sectional size than the cross-sectional size of the shaft portion with a component contact surface being defined between the head portion and the shaft portion, and for the insert to be inserted into the first component so that the component contact surface engages material of the first component. It is particularly preferred if the first insert is inserted into the first component so that a side of the head portion remote from the shaft portion is at least substantially flush with a first side of the first component remote from the second component. This design ensures that the thickness of the component assembly remains constant even in the area of the insert.

It is particularly preferred if the second insert also has a head portion and a shaft portion, the head portion being of a larger cross-sectional size than the crosssectional size of the shaft portion, with a component contact surface being defined between the head portion and the shaft portion, and if the insert is inserted into the second component so that the component contact surface engages material of the second component. Again a side of the head portion of the second insert remote from the shaft portion is preferably at least substantially flush with a side of the second component remote from the first component. This design also contributes to ensuring that the thickness of the component assembly remains constant even in the area of the inserts.

It is particularly preferred when the first insert has an end adjacent the second component or adjacent a second insert in the second component, with the said end projecting beyond the first component or beyond at least one first intermediate component adjacent the first component by an amount prior to welding which, after welding, has shrunk to zero or to a negative amount defining a compressive loading of the resulting component assembly.

It is particularly preferred for the first insert to have an end adjacent the second component or adjacent a second insert in the second component, the said end having at least one protrusion or chamfered region projecting beyond the first component or beyond at least one first intermediate component adjacent the first component by an amount prior to welding which, acts as a starter point for the welding and which, after welding and solidification and shrinkage of the weld pool, results in a compressive loading of the resulting component assembly.

The invention also relates to a component assembly made by any one of the aforementioned methods.

The component assembly is typically not restricted to the use of a single first insert but instead the component assembly will frequently comprise a plurality of first inserts welded to the second component. In an alternative the component assembly may also include a plurality of first inserts welded to a plurality of second inserts.

As indicated above the first component can comprise aluminium or an aluminium alloy and the second component comprises a steel. Alternatively, the first component can comprises a composite material such as a fibre or fabric reinforced thermoplastic or duroplastic and the second component can comprise a metal, e.g. steel.

In another alternative the first component can comprise a composite material such as a fibre or fabric reinforced thermoplastic or thermosetting plastic and the second component can comprise a composite material optionally dissimilar to the composite material of the first component.

Moreover, at least one first intermediate panel and/or at least one further intermediate panel is or are disposed between the first component and the second component and the intermediate panel or panels can each consist of a composite material or a metallic material or a ceramic material and plural intermediate panels can consist of different ones of these materials.

The invention also extends to an insert adapted for use in any of the aforesaid component assemblies or methods.

The invention will now be explained in more detail by way of example only with reference to preferred embodiments as illustrated in the accompanying drawings in which:

Fig. 1 shows a schematic cross-section through a first embodiment of the present invention,

Fig. 2 shows a schematic cross-section through a second embodiment of the present invention,

Fig. 3 shows a schematic cross-section through a third embodiment of the present invention,

Fig. 4 shows a schematic cross-section through a fourth embodiment of the present invention,

Fig. 5 shows a schematic cross-section through a fifth embodiment of the present invention,

Fig. 6 shows a schematic cross-section through a sixth embodiment of the present invention,

Fig. 7 shows a schematic cross-section through a seventh embodiment of the present invention,

Fig. 8 shows a schematic cross-section through an eighth embodiment of the present invention,

Fig. 9 shows a schematic cross-section through a ninth embodiment of the present invention,

Fig. 10 shows a schematic cross-section through a tenth embodiment of the present invention,

Fig. 11 shows a schematic cross-section through a variant of the invention using ultrasonic welding,

Fig. 12	shows a schematic cross-section through a variant of the invention using capacitor discharge welding,
Fig. 13	shows a schematic cross-section through a variant of the invention using explosive welding,
Fig. 14	shows a schematic cross-section through a variant of the invention using laser welding,
Fig. 15	shows a schematic cross-section through a variant of the invention in which a composite panel is being joined to a steel panel,
Fig. 16	shows a schematic cross-section through a variant of the invention in which an aluminium panel is being joined to a steel panel,
Fig. 17	shows a perspective view of one side of a composite component, here in the form of a tie-bar, having two first inserts in accordance with the present invention and showing the head end of the inserts,
Fig. 18	shows a perspective view of the other side of the tie-bar of Fig. 17 showing a chamfer and a pip at the other end of each of the inserts, and
Fig. 19	shows a schematic cross-section through an eleventh embodiment of the present invention.

Turning now to Fig. 1 there can be seen a schematic illustration of a first embodiment of the method of the present invention for joining first and second components 10, 12 of which the first component 10 is of a material not readily weldable to the second component 12. In this method a first insert 14 of a material weldable to the second component 12 is formed to transmit loads to the second component. For this purpose the insert 14 has a head portion 16 and a shaft portion 18, with the head portion 16 being of a larger cross-sectional size than the cross-sectional size of the shaft portion 18 and with a component contact surface 20 being defined on the head portion 16 at the junction to the shaft portion 18. In this embodiment both the head portion and the shaft portion are of circular or cylindrical cross-section. This is, however, by no means essential, the shaft portion 18 of the insert 14 can have any desired rosssection such as, without restriction, a square, polygonal, elliptical or star shaped cross-section or a cross-section provided with flutes or splines. The insert 14 can also be hollow. The head portion 16 of the first insert can have the same crosssectional shape as the shaft porton18 or a different shape, for example a head portion 16 with a circular cross-section can be used with any of the above described cross-sections of the shaft portion 18, or a head portion 16 of star shape can be used with a shaft portion 18 having any of the above named cross-sections.

The head portion 16 will almost invariably have a larger cross-sectional area than the shaft portion 18 so as to define a flange with a component contact surface to transmit compressive loads to the adjacent component 10. The area of the component contact surface 20, i.e. the difference between the cross sectional area of the head portion 16 and that of the shaft portion 18, should be made sufficiently large that the head portion 16 of the insert 14 can transmit the desired compressive load to the adjacent component without unduly deforming that component. Evidently the specific contact surface area has to be chosen having regard to the magnitude of the forces to be transmitted and the material involved, and whether it is desired for the head portion 16 to sit on the surface of the adjacent component 10 or to be fully or partially recessed within it.

In this embodiment the insert 14 is inserted into the first component 10 so that it is recessed within the component and the component contact surface 20 engages material of the first component. More particularly, the insert 14 is inserted into the first component 10 so that a side 22 of the head portion 16 remote from the shaft portion 18 is at least substantially flush with a first side 24 of the first component 10 remote from the second component 12.

Moreover, the first insert 14 is inserted into the first component 10 so that it extends from a first side 24 of the first component 10 to a second side 25 of the first component 10 adjacent the second component 12.

The reference numerals 26 and 28 indicate the tips of first and second spot welding electrodes. In known manner these spot welding electrodes are connected to a spot welding gun (not shown) which is adapted to press the two tips 26, 28 towards one another while exerting a clamping force on the items 14 and 12 between the tips and to pass a current between the tips for a period of time sufficient to spot weld the items 14 and 12 together. The current causes heating at the interface between the first insert 14 and the second component 12 which results in a weld pool being formed there, which is squashed radially outwardly under the clamping force and which solidifies after the cessation of the current to form a weld spot 30.

The first insert 14 is thus joined by fusion to the second component 12 and firmly clamps the first component against the second component, due to the tensile stress induced in the first insert by the welding process and shrinkage of the weld pool on cooling, as well as due to the contact surface 20 of the first insert transmitting this tensile stress through the first component 10 to the second component 12.

Compression and clamping of the workpieces during spot welding as well as the potential for clamp load resulting from shrinkage of the weld pool. This compression and clamping of the workpieces during spot welding is a key part of the process of the invention. Even in the absence of shrinkage effects a clamp load may also be created in compressible materials by introducing an overload force during the welding process. Once the weld is complete and the press force removed, the expansion of the material creates some degree of clamp load.

As shown in Fig. 18 the free end 32 of the first insert 14 can be provided with a chamfer 34 (shown in Fig. 18) and or one or more projecting pips 36 (shown in Fig. 18) so that the welding current is initially concentrated at the free end 32 leading to controlled melting of the free end 32 of the first insert 14.

At this stage it should be emphasized that an important concept of the present invention is to retain the insert 14 in place in the adjacent component 10 during handling, transport etc, up to the point of the final assembly at some later time and location. The insert can be regarded as a “captive” insert which is then welded. Having a loose insert to pick-up and position prior to welding is a process inconvenience compared to an already captive part, perhaps installed by a subcontract tier supplier.

Fig 2 shows an embodiment very similar to Fig. 1 but in this case the head portion 16 of the first insert 14 is positioned outside of the first side 24 of the first component 10 with the contact surface 20 contacting this first side 24. It can be that the insert 14 in Fig. 2 has been shown with a much larger diameter head relative the shaft diameter. The idea here is to describe the extra advantage of introducing a larger bearing area for spreading compressive loads in composite, plastic or softer metal panels. A traditional spot weld is small in diameter but a large head insert could alleviate this stress in the panel without having any impact on the size of the spot weld. The larger head size in Fig. 2 can be used in any of the other embodiments if desired

In the embodiment of Figs. 1 and 2 the second component 12 can be of a readily weldable material such as steel or a weldable grade or alloy of aluminium or of another metal, whereas the first component 10 can be of a different material or metal not readily weldable to the second component 12, such as a non weldable grade or alloy of aluminium, if the second component 12 is of a weldable grade of aluminium. Alternatively, the first component 10 can be of any grade or alloy of aluminium if the second component 12 is of steel or it can be of a composite material if the second component 12 is of steel or of another weldable metal. If the second component 12 is of steel the first insert 14 will typically also be of steel. If the second component 12 is of another weldable metal the first insert 14 will be of a metal readily weldable to the metal of the second component 12. For example, it could a weldable grade of aluminium or aluminium alloy if the second component is a weldable grade or alloy of aluminium.

The above considerations apply also to the further embodiments unless something to the contrary is specifically stated.

In the following description the same reference numerals will be used for components or items having the same general layout or function and the previous description will be understood to apply to them unless something is stated to the contrary.

Turning now to Fig. 3 there is shown an embodiment similar to that of Fig. 2 but in which a second insert 38 is provided in the second component 12 and the initially free end 40 of the second insert is welded to the initially free end 32 of the first insert

14. The second insert 38 again has a head portion 42 and a shaft portion 44 of smaller cross-sectional size with a contact surface 46 being defined on the head portion 42 at the junction with the shaft portion 44. As shown in Fig. 3 the head portion 42 is outside of the second component 12 such that the contact surface 46 contacts a side 48 of the second component 12 remote from the first component 10.

It should be emphasized that all the considerations recited above in relation to the first insert 14 apply equally to the second insert 38. This includes considerations such as the size and shape of the shaft portion and the head portion, shrinkage of the weld pool, the degree to which the head portion is recessed into the second component(if at all) and the ease of handling with a captive second insert 38.

In Fig. 4 both the head portion 16 of the first insert 14 and the head portion 42 of the second insert 38 are pressed into the respective components or panels 10, 12 so that the outer sides of the head portions 16 and 42 are substantially flush with the outer sides 24 and 48 of the first and second components 10, 12.

In both the embodiment of Fig. 3 and that of Fig. 4 the first insert 14 is joined by fusion to the second insert 38 as illustrated by the weld spot or bead 30. This design provides even greater flexibility in the choice of materials for the first and second components 10, 12 since the second component can now be made not only of weldable material but also of non-weldable material. Thus the first and second components 10, 12 could each be of composite material or could both be of nonweldable grades or alloys of aluminium. In both cases the first and second inserts can be of steel or aluminium or of a weldable grade or alloy of aluminium.

The second insert 38 is inserted into the second component 12 so that a side 54 of the head portion 42 remote from the shaft portion 44 is at least substantially flush with a side 48 of the second component 12 remote from the first component 10.

In the figures shown so far the first and second components 10, 12 each take the form of a panel and in all figures, apart from Figs. 17 and 18, the first and second components are panels. This is, however, by no means essential, the first component or the second component could be a flange or foot of any desired component, for example a fuse box or voltage regulator to be attached to a second component in the form of a metal panel or a composite panel.

The embodiment of Fig. 5 shows a variant of the method similar to that of Fig. 2 in which the free end of the first insert is provided with a deposit of braze or solder 50. On applying a pulse of current to the spot welding electrodes the braze or solder melts and joins to the metallic material of the second component so that the first insert is brazed or soldered to it as can be seen from the molten braze deposit 52.

Fig. 6 shows an arrangement similar to that of Fig. 2 in which an intermediate panel 60 is provided between the first component 10 and the second component 12. The first insert 14 is inserted into the first component 10 and the intermediate panel 60 so that it extends from the first side 24 of the first component 10 remote from the at least one intermediate panel 60 to a side 62 of the intermediate panel 60 adjacent the second component 12.

Fig. 7 shows a further development of Fig. 6 in which a second intermediate panel 64 is provided. Fig. 7 also shows the head portion 16 of the first insert recessed into the first component 10 as in Fig. 1 and this recessed arrangement could also be used in the embodiment of Fig. 5.

Fig. 8 shows an alternate arrangement similar to Fig. 4 but with an intermediate panel 66 provided between the first component 10 and the second component 12.

Here the first insert 14 is inserted into the first component 10 and extends from a first side 24 of the first component 10 remote from the intermediate panel 66 to a second side 68 of the first component 10 adjacent the intermediate panel 66. A second insert 38 is provided in the second component 12 and in the intermediate panel 66 and extends from the side 48 of the second component 12 remote from the intermediate panel 66 through the second component 12 and the intermediate panel 66 to a position adjacent the first insert 14

Fig. 9 shows an arrangement similar to that of Fig. 8 but here there is provided a second intermediate panel 70 and the second insert 38 extends also through this second intermediate panel 70 to a position adjacent the first insert 14.

Arrangements (not shown) are also conceivable in which at least one first intermediate panel 60 is provided adjacent the first component 10 and at least one further intermediate panel 70 is provided adjacent the second component 12 and adjacent the at least one first intermediate panel 60. In such an arrangement the first insert 14 is inserted into the first component 10 and extends from a first side of the first component remote from the first intermediate panel 60 through the first component 10 and the at least one first intermediate panel 60 to a position adjacent an end of a second insert 38 provided in the second component 12 and extending from a side of the second component 12 remote from the at least one further intermediate panel 70 through the second component 12 and through the at least one further intermediate panel 70.

Fig. 10 illustrates an embodiment similar to Fig. 1 but in which the first insert is provided with a bore 72 and a thread cylinder 74. This necessitates the tip of the spot welding electrode 26 being increased in size or being changed in shape so that it contacts a ring surface at the head portion 16 of the first insert. After completing the component assembly of Fig. 10 a further component can be attached thereto using a bolt (not shown) engaging into the thread cylinder 74.

In the above embodiments the fusion step for joining the first insert 14 to the second component 12 or to the second insert 38 has been performed by spot welding or at least by using spot welding electrodes to apply heat to a deposit of braze or solder.

Fig. 11 illustrates an alternative in which ultrasonic welding is used to join a first plastic insert 14 to a second plastic insert 38. In manner known per se for ultrasonic welding a sonotrode 80 receiving ultrasonic energy from a transducer 82 to which a force is applied in the direction of arrow 84 contacts the head of the first insert 14 while the head of the second insert 38 is supported on an anvil or holding plate 86. The ultrasonic energy is concentrated at the interface between the first and second inserts 14 and 38 causing them to be ultrasonically welded to each other. This embodiment has the advantage that it can be used with components of virtually any material which is stiff in compression and which differ from the material of the inserts and can be used for joining the most diverse materials. Also it minimizes the heat input into the components.

The embodiment of Fig. 12 illustrates the use of capacitive discharge welding. Here a capacitor 90 is charged by a charging circuit 92 and is connected to the second component 12 directly and to the first insert 14 via a switch 94 (or vice versa). On closing the switch, a current flows between the insert 14 and the second component 12, causing the insert 14 and the second component 12 to fuse together at the interface between them, thus forming the weld spot 30. It is helpful for the first insert 14 to be pressed into contact with the second component 12 during the welding operation.

Fig. 13 illustrates an embodiment similar to Fig. 2 in which explosive welding is used to weld the first insert to the second component 12. In this drawing the reference numeral 100 represents an explosive charge. A detonator circuit 102 is connected to the explosive charge by wires 104 and 106. The explosive charge 100 could also be replaced by a bath of water or other fluid into which an electrical discharge is made from a charged capacitor analogous to the capacitor shown in Fig. 12. A capacitive discharge in a fluid leads to an explosive pressure wave and this can be exploited to carry out the fusion process.

Fig. 14 illustrates an embodiment in which the fusion process is carried out between two inserts 14 and 38 by means of a laser 108. The two inserts 14 and 38 are preferably translucent or transparent and can consist of a suitable plastic. The laser energy can be concentrated at the interface between the two inserts 14 and 38 so that they are laser welded to one another to form the weld spot 30.

It will be appreciated that the different welding methods explained with reference to Figs. 11 to 14 are not restricted to the precise component assemblies shown but can be used in modified form with the various component assemblies shown in Figs. 1 to 10 and Fig. 19 discussed in the following.

Turning now to Fig. 15 there can be seen an embodiment similar to that of Fig. 1 but specifically adapted to joining a composite material panel 10 to a steel panel 12. This embodiment addresses the problem that many manufacturing lines have a huge investment in automated spot welding processes and would like to continue using this process for new lightweight materials. Composites, such as thermoset carbon fibre components, cannot be welded.

The idea here is to punch a hole in the thermoset carbon fibre component 10 and to insert a localised steel tack point (the insert 14) to allow spot welding steel-to-steel. (Similar to the Penn SFK element but now used in one component only). The composite top component 10 is held in place by the broaching flutes 110 and the flush or large diameter contact head 16.

This is a specific example of broach and clinch technologies being used to ensure the insert is a captive insert. The flutes ensure the insert is secured against rotation and the clinching results in squashing of the insert forming an undercut here in the form of a V-groove 112 which locates the insert axially within the component.

However it should be noted that an insert does not have to be fitted by broaching and clinching, loose fitted inserts and inserts with an interference fit can also readily be used. Broaching alone can be used for hard or brittle materials and clinching is for ductile material which can cold-flow using a displacer and undercut feature.

The broaching version shown in Fig. 15 provides an anti-rotation feature. Security against rotation can also be achieved by a non-circular cross-section of the shaft portion and/or of the head portion of the insert.

There are some cases in which rotation after installation may be advantageous, as an axel or pivot, For example one can envisage little pivoting parts such the ejection arms for sim cards in phones etc. A mount for an axle can also be provided by using hollow inserts.

Fig. 16 illustrates another embodiment similar to Fig. 1 but specifically adapted to join an aluminium panel 10 to a steel panel 12. This embodiment addresses the problem that many manufacturing lines have a huge investment in automated spot welding processes and would like to continue using this process for new lightweight materials. Aluminium needs special preparation to allow welding.

The idea here is to punch a hole in the first aluminium component 10 and to insert a localised steel tack point (the insert 14) to allow spot welding the steel insert 14 to the steel panel 12. The aluminium top component is held in place by the clinch and flush head. (Similar to the Penn SF element but now used in one component only).

Fig. 17 illustrates a carbon fibre component 10 in the form of a tie-bar consisting of carbon fibres embedded in an epoxy resin. The ends of the tie-bar are of increased area for attachment purposes and the one end 120 shown in Fig. 17 is provided with two steel inserts 14 of which the head portions 16 of larger diameter than the shaft portions 18 (Fig. 18) can be seen the inserts 14 are fitted into broached bores in the first component and project through it. As can be seen from Fig. 18, which shows the underside of the tie-bar the exposed ends of the shaft portion of the steel inserts 14 each have a chamfer 34 and a projecting pip 36 which facilitates the spot welding of the inserts to a steel panel 12 by which the tie-bar is secured to the steel panel.

Fig. 19 illustrates an embodiment similar to Fig. 10 but in which the first insert is 5 provided with a threaded shaft 122 having a thread 124 at the side 22 of the first insert 14 remote from shaft 18. The tip of the spot welding electrode 26 can be changed in size and/or shape so that it contacts the threaded shaft 122 of the first insert 14 and/or the side 22 of the first insert 14. After completing the component assembly of Fig. 19 a further component (not shown) can be attached thereto using a nut element (also not shown) engaging the threaded shaft 122.

Reference numeral list:

first component or panel second component or panel first insert head portion of first insert shaft portion of first insert contact surface of first insert side of head 16 of first insert 14 remote from shaft portion 18 side of first component remote from second component 12 side of first component adjacent to second component 12 first electrode of spot welding gun second electrode of spot welding gun weld spot, weld bead, free end of first insert 14 remote from the head portion 16 34 chamfer at free end 32 prior to welding 36 pip at free end 32 prior to welding 38 second insert free end of second insert 38 head portion of second insert shaft portion of second insert contact surface side of second component remote from the first component 10 deposit of braze or solder molten deposit after solidification side of insert 38 intermediate panel side of intermediate panel second intermediate panel intermediate panel second side of the first component 10 second intermediate panel bore thread cylinder sonotrode transducer arrow anvil, holding plate capacitor charging circuit switch

100 explosive charge

102 detonator circuit

104 wire

106 wire

108 laser

110 broaching flutes

112 V-shaped groove, undercut

120 end

122 threaded shaft

124 thread

Claims

Claims:

1. A method of joining first and second components (10, 12) of which the first component (10) is of a material not readily weldable to the second component (12), wherein a first insert (14) of a material capable of being fused to the second component (12), or to a second insert (38) provided in the second component and formed to transmit loads to the second component (12), is inserted into the first component (10) and is formed to transmit loads to the first components 0), and wherein the first insert (14) is subsequently joined by fusion to the second component (12) or to a said second insert (38) provided in the second component.

2. A method in accordance with claim 1 in which at least one of the first and second components (10, 12) is a panel.

3. A method in accordance with claim 1 or claim 2, wherein the step of joining the first insert (14) to the second component (12) or to a said second insert (38) by fusion is performed by one of spot welding, induction welding, by explosive welding, by capacitor discharge welding, by laser welding, by ultrasonic welding, or by brazing or soldering.

4. A method in accordance with any one of claims 1,2 or 3, wherein the first insert (14) is provided at an end adjacent the second component (12) with a deposit (50) of braze material or solder material and is joined by brazing or by soldering to the second component (12), or to a second insert (38) provided in the second component (12), by the introduction of heat energy by spot welding, by induction, by explosion, by capacitor discharge or by ultrasound.

5. A method in accordance with claims 1,2 or 3, wherein the first insert (14) comprises a material capable of being ultrasonically welded to the second component (12), or to a second insert (38) provided in the second component (12), and is joined to the second component (12) or to a second insert (38) provided in the second component (12) by ultrasonic welding.

6. A method in accordance with any one of the preceding claims, wherein the first insert (14) is inserted into the first component (10) so that it extends from a first side (24) of the first component (10) to a second side (25) of the first component (10) adjacent the second component (12) or adjacent to an end (40) of a second insert (38) provided in the second component.

7. A method in accordance with any one of the preceding claims, wherein at least one intermediate panel (60) is provided between the first component (10) and the second component (12) wherein the first insert (14) is inserted into the first component (10) and the at least one intermediate panel (60) so that it extends from a first side (24) of the first component remote from the at least one intermediate panel (60) to a side of an intermediate panel (60) adjacent the second component (12), or adjacent to an end of a second insert (38) provided in the second component (12).

8. A method in accordance with any one of the preceding claims 1 to 6, wherein at least one intermediate panel (66) is provided between the first component (10) and the second component (12) wherein the first insert (14) is inserted into the first component (10) and extends from a first side of the first component (10) remote from the at least one intermediate panel (55) to a second side of the first component (10) adjacent the intermediate panel (66) and wherein a second insert (38) is provided in the second component (12) and in the at least one intermediate panel (66) and extends from a side of the second component remote from the at least one intermediate panel (66) through the second component and the at least one intermediate panel to a position adjacent the first insert (14).

9. A method in accordance with any one of the preceding claims 1 to 6, wherein at least one first intermediate panel (60) is provided adjacent the first component (10) and at least one further intermediate panel (66) is provided adjacent the second component (12) and adjacent the at least one first intermediate panel (60), wherein the first insert (14) is inserted into the first component (10) and extends from a first side of the first component (10) remote from the first intermediate panel (60) through the first component (10) and the at least one first intermediate panel (60) to a position adjacent an end of a second insert (38) provided in the second component (12) and extending from a side of the second component (12) remote from the at least one further intermediate panel (66) through the second component (10) and through the at least one further intermediate panel (66).

10. A method in accordance with at least one of claims 1,2 and 3, wherein the first insert (14) comprises a material capable of being ultrasonically welded to the second component (12), or to a second insert (38) provided in the second component (12) and is joined to the second component (12) or to an insert (38) provided therein by ultrasonic welding.

11. A method in accordance with any one of the preceding claims wherein the first insert (14) has a head portion (16) and a shaft portion (18), the head portion (16) being of a larger cross-sectional size than the cross-sectional size of the shaft portion (18) with a component contact surface (20) being defined at the head portion (16) at the junction between the head portion (16) and the shaft portion (18), wherein the insert (14) is inserted into the first component (10) so that the component contact surface (20) engages material of the first component (10).

12. A method in accordance with claim 11, wherein the insert (14) is inserted into the first component (10) so that a side (22) of the head portion (16) remote from the shaft portion (18) is at least substantially flush with a first side (24) of the first component (10) remote from the second component (12).

13. A method in accordance with any one of the preceding claims wherein the second insert (38) has a head portion (42) and a shaft portion (44), the head portion (42) being of a larger cross-sectional size than the cross-sectional size of the shaft portion (44) with a component contact surface (46) being defined between the head portion (42) and the shaft portion (44), wherein the insert (38) is inserted into the second component (12) so that the component contact surface (46) engages material of the second component (12).

14. A method in accordance with claim 13, wherein the insert (38) is inserted into the second component (12) so that a side (54) of the head portion (42) remote from the shaft portion (44) is at least substantially flush with a side (48) of the second component (12) remote from the first component (10).

15. A method in accordance with any one of the preceding claims wherein the first insert (14) has an end (32) adjacent the second component (12) or adjacent a second insert (38) in the second component (12), the said end (32) projecting beyond the first component (10) or beyond at least one first intermediate component (60;66) adjacent the first component (10) by an amount prior to welding which, after welding, has shrunk to zero or to a negative amount defining a compressive loading of the resulting component assembly.

16. A method in accordance with any one of the preceding claims 1 to 14 wherein the first insert (14) has an end (32) adjacent the second component (12) or adjacent a second insert (38) in the second component (12), the said end (32) having at least one projecting pip (36) projecting beyond the first component (10) or beyond at least one first intermediate component (60;66) adjacent the first component (10) by an amount prior to welding which, acts as a starter point for the welding and which after welding, results in a compressive loading of the resulting component assembly.

17. A method in accordance with any one of the preceding claims, wherein at least one of the first insert and any second insert is a hollow insert (14) provided with an internal thread cylinder (74) or a solid insert provided with a projection having an external thread.

18. A component assembly made by the method of any one of the preceding claims.

19. A component assembly in accordance with claim 18, wherein the component assembly comprises a plurality of first inserts (14) welded to the second component (12).

20. A component assembly in accordance with claim 18, wherein the component assembly includes a plurality of first inserts (14) welded to a plurality of second inserts (38).

21. A component assembly in accordance with any one of claims 18 to 20, wherein the first component (10) comprises aluminium or an aluminium alloy and the second component (12) comprises a steel.

22. A component assembly in accordance with any one of claims 18 to 20, wherein the first component (10) comprises a composite material such as a fibre or fabric reinforced thermoplastic or thermosetting plastic and the second component (12) comprises a metal.

23. A component assembly in accordance with any one of claims 18 to 20, wherein the first component (10) comprises a composite material such as a fibre or fabric reinforced thermoplastic or thermosetting plastic and the second component (12) comprises a a composite material optionally dissimilar to the composite material of the first component (10).

24. A component assembly in accordance with any one of the preceding claims 18 to 23 wherein at least one first intermediate panel (60; 66) and/or at least one further intermediate panel (60; 66: 70) is or are disposed between the first component (10) and the second component (14) and consists or consist of a composite material, or a metallic material or a ceramic material.

25. A component assembly in accordance with any one of the claims 18 to 24,

5 wherein at least one of the first insert (14) and any second insert (38) is a hollow insert provided with an internal thread (74) or a solid insert provided with a projection having an external thread (124).

26. An insert (14; 38) for use in a method in accordance with any one of claims 1 10 to 17.

27. An insert (14;38) for use in a component assembly in accordance with any one of claims 18 to 25.

Intellectual

Property

Office

Application No: GB1700385.6