FR3108552A1 - Method of making a locked assemblage point and resulting assemblage point - Google Patents

Abstract

Method of making a locked assembly point and resulting assembly point The present invention relates to a method of making a locked assembly point (1) between a first part (2) comprising a protruding formation and a second part (3) comprising a wall portion (5) with an opening (6) for the passage through the protruding formation, said method essentially comprising a first operating step of mechanical pre-assembly of the parts (2, 3) with introduction of the formation through the opening (6) and a second process step of forming a head (1'') of the rivet (1') with the part of the formation protruding beyond the hole (6). This method is characterized in that after mechanical pre-assembly, the protruding formation is subjected to a pinching at the level of the opening (6) resulting from a deformation under stress, by said formation, of at least one zone ( 7, 7') elastically deformable of the wall portion (5). Figure to be published with abstract: Fig. 7B

Description

Method of making a locked assembly point and resulting assembly point

The present invention relates to the field of the assembly of at least two parts, more particularly by riveting, and has as its objects a method of producing a locked assembly point between at least two parts by ultrasonic riveting or the like, an assembly point obtained by this process and an assembly formed by two parts assembled by at least one such assembly point.

Many processes for assembling two parts by riveting are already known.

In particular, methods are known in which a locked assembly is produced between at least two parts by ultrasonic riveting or by a means of transferring or generating similar thermal energy, without implementing a separate additional fastening part.

These methods consist, for the most part, in first providing a first part comprising a protruding formation forming a blank or rivet precursor, preferably profiled, and a second part comprising a wall portion with a hole or opening for the passage through the salient formation. Then, said method essentially comprises a first operating step of mechanical pre-assembly of the parts with introduction of the formation through the hole or the opening and a second operating step of forming a rivet head with the part of the formation protruding beyond the hole, by material fusion by ultrasonic vibrations or the like. Documents US 2009/0119860, DE 2641804, WO 2009/077217, DE 10124920 and EP 2 020 285 illustrate examples of riveting methods of the type mentioned above.

In these processes, it is common after manufacture of each of the parts to be assembled, to pre-assemble them in their final assembly configuration, and to transfer them from a first pre-assembly station to a second riveting station for the final assembly. Such a transfer can be done directly between the two aforementioned stations, or else by passing through one or more other intermediate stations for the performance of other operations. The duration and distance of such a transfer, in one or more stages, can also vary, and for example take place between two different sites, or even between two different and geographically spaced factories. Such a single transfer operation or a series of successive transfer operations is difficult to carry out since perfect preservation of the pre-assembly positioning is sought, while the parts are not yet rigidly attached to each other and often the precision of the initial positioning is lost, see the pre-assembly as such, at the end of the transfer.

The problem posed therefore consists in finding a solution to ensure a firm hold of the pre-assembled parts together and therefore conservation of the pre-assembled assembly, so as to be able to move, handle and transport, without any particular precaution, this assembly between the pre-assembly and the riveting station, while retaining this pre-assembly.

Furthermore, the proposed solution should be safe, simple to implement, inexpensive and not require any additional component.

To this end, the subject of the invention is a method for producing an assembly point locked by ultrasonic riveting (or by a similar energy transfer means) as mentioned above, characterized in that after mechanical pre-assembly, the protruding formation is subjected to a clamping or pinching at the level of the hole or of the opening, this clamping or pinching resulting from a deformation under stress, by said formation, of at least one elastically deformable zone of the wall portion, each comprising a free edge intended to come into contact with the formation, contributing to the delimitation of the passage of the hole or of the opening and located at the level of the internal contour of the latter.

The invention will be better understood, thanks to the description below, which relates to preferred embodiments, given by way of non-limiting examples, and explained with reference to the appended diagrammatic drawings, in which:

And

illustrate the two components for producing an assembly point locked by riveting, according to a first embodiment of the invention, before the pre-assembly step;

is a perspective view of the blank of the riveting point after pre-assembly of the two components of FIGS. 1A and 1B;

is a partial sectional view, at the level of the blank of the future riveting point of FIG. 2, of the first and second parts to be assembled;

is a partial sectional view similar to that of FIG. 3 after the operation of forming the rivet by applying ultrasound;

is a partial perspective view illustrating the pre-assembly operation resulting in the configuration of Figures 2 and 3;

is a partial view of a second part showing an alternative embodiment of the through opening of FIGS. 1A and 5;

And

are partial cross-sectional views (at an assembly point) of two parts after the pre-assembly operation (Fig. 7A) and after the riveting operation (Fig. 7B), in accordance with a second embodiment;

And

are partial views, respectively in perspective (8A) and in section (8B), of two parts after the pre-assembly operation, in accordance with the second embodiment of the invention;

And

are partial top views of two constructive variants of the embodiment of FIGS. 7 and 8 (with respectively an elliptical hole and a circular hole);

is a partial top view, at a future assembly point, of two parts after pre-assembly, in accordance with a third embodiment of the invention, and,

And

are partial sectional views of the two parts of Figure 10 after pre-assembly (Fig. 11A) as in Figure 10 and after riveting (Fig. 11B), the section being made along section plane AA of Figure 10 .

Figures 1 to 11 illustrate different steps of the method of producing a locked assembly point 1 between at least two parts by three different embodiments of the invention.

This device consists first of all in providing a first part 2 comprising a projecting formation 4 forming a blank or precursor of a rivet, preferably profiled, and a second part 3 comprising a wall portion 5 with a hole or opening 6 for the passing through the protruding formation 4. This method essentially comprises a first operating step of mechanical pre-assembly of the parts 2, 3 with introduction of the formation 4 through the hole or the opening 6 and a second operating step of forming a head 1″ of rivet 1′ with the part 4′ of the formation 4 protruding beyond the hole 6, by melting material by ultrasonic vibrations or a similar technology (making it possible to provide the caloric energy necessary for the heating of the material of the 4' part and the formation of the rivet head after fusion).

According to the invention, this method is characterized in that after mechanical pre-assembly, the protruding formation 4 is subjected to tightening or pinching at the level of the hole or of the opening 6 resulting from a deformation under stress, by said formation 4, of at least one elastically deformable zone 7, 7' of the wall portion 5, each comprising a free edge 8 intended to come into contact with the formation 4, participating in the delimitation of the passage of the hole or the opening 6 and located (s) at the internal contour 6 'of the latter.

Thus, the invention provides a solution that is simple, effective, inexpensive and does not require any additional component, which ensures maintenance of the mechanical pre-assembly connection provided by the or each pair [formation 4/hole-opening 6] each constituting a precursor of an assembly point locked 1 by riveting. Preferably, the assembly of the two parts 2 and 3 takes place via several assembly points 1 with distributed rivets 1'. Holding by tightening or pinching after pre-assembly can take place either between two elastically deformable zones 7 and 7' (Figures 7 to 11), or between an elastically deformable zone 7 and an opposite (non-deformable) part of the internal edge 6 'Hole or opening 6 (Figures 1 to 6).

In addition, the or each elastically deformable zone 7, 7' can be located, at rest at least, in the plane or the thickness of the second part 3 or of the part of this part surrounding the hole 6, or be protruding ( s) relative to this part 3 beyond the face 5' of the wall portion 5.

The or each zone 7, 7' advantageously constitutes a bridge of material, plane or not, configured to come into contact with the formation 4 with stressing by pressure, by undergoing at least a slight elastic deformation by bending and by ensuring a pinching of said formation 4.

Part 4' of formation 4 naturally includes enough material to form a rivet head 1'' wide enough to make a rigid and resistant connection with said formation 4 hooking into hole 6 of second part 3.

In accordance with a characteristic of the invention, making it possible to achieve blocking of the pre-assembly, said at least one deformable edge zone 7, 7' opposes, when it is deformed by the introduction of the formation protrusion 4 in hole 6, upon retraction of said formation 4 from said hole 6. At least when protruding formation 4 has passed said at least one elastically deformable zone 7, 7', the intensity of the force required to withdraw the formation 4 is preferentially greater than the intensity of the force necessary for an additional introduction or further ahead thereof.

Advantageously, provision is made to provide one or more elastically deformable zones 7, 7' whose profile or contour of the contact edge 8, which comes into engagement with the protruding formation 4, has a shape substantially conjugate with that of the corresponding part of the outer face 9 of the latter (for example in an arc of a circle), said contact edge 8 being configured to oppose the withdrawal of the protruding formation 4 when it is resting under elastic stress against it and thus preserving the pre-assembly of the first and second parts 2 and 3.

As partially shown in the appended figures, the profiled protruding formation 4, the hole 6 and the deformable zones 7, 7' with their contact edges 8 can have various constitutions and shapes.

However, preferentially, the profiled protruding formation 4, hollow or solid, has a circular, elliptical or rectangular section and the or each contact edge 8 has a beveled shape in section, defining an engagement edge 8' opposing the extraction of the formation 4.

Where appropriate, the outer face of the formation 4 and / or the or each edge 8 may (may) include roughness, notches or similar means of contact with high friction contributing to a better maintenance of the interlocking of the formation 4 in hole 6.

Preferably, and with a view to achieving a rigid and wedged pre-assembly connection, the movement of introduction of the protruding formation 4 into the hole 6 is continued until arriving at a stop or abutment position or configuration .

As shown in FIGS. 1B, 3, 4 and 5 in particular, as well as in FIG. 11, the abutment configuration may correspond to the wall portion 5 comprising the hole 6 coming into contact with one or more abutment structures 10 (S) around the base of the protruding formation 4 on the first part 2 and formed in one piece with the latter, of the rib or support wing type.

In order to allow a limited relative movement between the pre-assembled parts 2, 3 and possibly make it possible to compensate for dimensional, manufacturing and multipoint bonding tolerances, provision may be made for the elastic clamping of the protruding formation 4 in the hole 6 to be effective mainly in a given direction DS, advantageously secant with the longitudinal axis AL of the protruding formation 4 and substantially transverse with respect to this axis, said protruding formation 4 being advantageously subjected to a position indexing stress in a direction perpendicular to the aforementioned tightening direction DS (conjugate shapes of the edges 8 and the outer face 9), but preferably with the possibility of play or dispersion in directions perpendicular to the direction DS.

According to a first embodiment, illustrated in FIGS. 1 to 6, the hole 6 comprises a single elastically deformable zone 7, located in the plane of the wall 5, at least in the absence of the protruding formation 4, formed in the edge 6' of the hole 6 and being in the form of a tongue obtained by making two similar slots or cutouts 11, 11', laterally delimiting the said tongue 7 and made in the wall portion 5 comprising the hole 6, forming part of the perimeter of the latter.

As shown by way of example in FIGS. 1A, 2, 5 and 6, the hole 6 has an outline in the shape of the silhouette of a cat's head, the deformable zone 7 extending between the cat's ears.

To make zone 7 more flexible, an additional cutout or opening 14 can be provided at a distance from edge 8, at the rear of zone 7 and between the ends of the cat's ears.

According to a second and a third embodiment, emerging from Figures 7 to 9, on the one hand, and from Figures 10 and 11, on the other hand, it can be provided that the hole or the opening 6 comprises elastically deformable zones 7 and 7', configured to receive the protruding formation 4 between them and being in the form of structures forming an integral part of the wall portion 5 and extending prominently on the face 5' of the latter which is opposite the first part 2, the edges or contact zones 8 of said structures 7 and 7' with the protruding formation 4 being located outside the plane of the wall portion 5 in the absence of deformation, i.e. say before introduction of training 4.

For example, the two elastically deformable structures 7 and 7' come into contact with the protruding formation 4 outside the thickness of the wall portion 5 and consist of two mutually opposite tongues, for example formed in the inner edge 6' of the hole 6 or locally extending the latter. (see figures 7 to 9).

Advantageously, the two tabs 7 and 7' are each delimited by two similar slots or cutouts 11 and 11', made in the wall portion 5 comprising the hole 6 and forming part of the contour 6' of the latter.

In accordance with the third embodiment, emerging from Figures 10 and 11, the two elastically deformable structures 7 and 7 ', preferably two tongues with contact edges 8 in the form of edges or bevelled, advantageously have an S configuration or in Z in section and, ensure the holding of the protruding formation 4 in the hole 6, alone or in cooperation with complementary portions 6'' of the internal contour 6' of the hole 6. The formation 4 is thus contacted in two offset planes in the plane of 3 and in the plane containing the edges 8.

As illustrated in particular in FIGS. 4, 7B and 11B, the quantity of material of the protruding formation 4 intended for the formation of the head 1″ of the rivet 1′ is sufficient to cover, and preferably encapsulate, the elastically deformable 7, 7' after softening by supplying energy of at least a fraction of the material of the protruding part 4' of the formation 4, preferably of the whole of this last part, with a possible filling of the hollow interior of said formation 4 and possible rapprochement until the first and second parts 2 and 3 are brought into contact.

In accordance with a particularly advantageous characteristic of the invention, each elastically deformable zone 7, 7' is made of a thermoplastic material which is compatible with that constituting the protruding formation 4, the material melting operation by ultrasonic vibrations or the like for the production of the head 1″ of the rivet 1′ being continued until the material of the part 4′ of the formation 4 has melted and at least the start of melting of the material of the zone or zones 7, 7′. This produces not only a mechanical attachment, but also material.

The method according to the invention is preferably provided for the assembly of two parts 2 and 3.

However, according to a possible embodiment variant, provision may be made for at least one third part 12, possibly a wedging or spacer part, to be placed between the first 2 and second 3 parts, during pre-assembly, and is preferably sandwiched tightly between the latter after finalization of the assembly.

According to an additional advantageous characteristic, the relative positions of the two parts 2 and 3 to be assembled together are determined by additional mechanical indexing means 13, 13', for example complementary means cooperating by interlocking after the pre-assembly phase, in particular of the orifice-lug type, located close to the hole assembly 6 protruding formation 4.

The invention also relates, as shown in FIGS. 4, 7B and 11B, to an assembly point 1 by riveting between two parts 2 and 3, characterized in that it was obtained by means of the method described below. above.

Finally, the invention also relates to a composite assembly of at least two parts 2, 3 assembled by riveting, characterized in that it comprises at least one, preferably several, assembly point(s) 1 of the aforementioned type, obtained by the method described above.

Of course, the invention is not limited to the embodiments described and shown in the appended drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims (19)

A method of making a locked connection point (1) between at least two parts (2, 3) by ultrasonic riveting, said method first comprising providing a first part (2) comprising a protruding formation (4 ) forming a rivet blank or precursor, preferably profiled, and a second part (3) comprising a wall portion (5) with a (e) hole or opening (6) for the passage through the protruding formation (4) and said method essentially comprising a first operating step of mechanical pre-assembly of the parts (2, 3) with introduction of the formation (4) through the hole or the opening (6) and a second operating step of forming a head ( 1'') of rivet (1') with the part (4') of the formation (4) protruding beyond the hole (6), by material fusion by ultrasonic vibrations,
method characterized in that after mechanical pre-assembly, the protruding formation (4) is subjected to a clamping or pinching at the level of the hole or of the opening (6) resulting from a deformation under stress, by said formation (4 ), at least one elastically deformable zone (7, 7') of the wall portion (5), each comprising a free edge (8) intended to come into contact with the formation (4), contributing to the delimitation of the passage of the hole or of the opening (6) and situated at the level of the internal contour (6') of the latter. Method according to Claim 1, characterized in that the said at least one deformable edge zone (7, 7') opposes, when it is deformed by the introduction of the protruding formation (4) into the hole (6) , upon the retraction of said formation (4) from said hole (6) and, in that at least when the protruding formation (4) has passed said at least one elastically deformable zone (7, 7'), the intensity of the force necessary for the withdrawal of the formation (4) is greater than the intensity of the force necessary for a further or further introduction of it. Method according to either of Claims 1 and 2, characterized in that it consists in providing one or more elastically deformable zones (7, 7') whose profile or contour of the contact edge (8), which comes into engagement with the protruding formation (4), has a shape substantially matching that of the corresponding part of the outer face (9) of the latter, said contact edge (8) being configured to oppose the withdrawal of the protruding formation (4) when it bears under elastic stress against it and thus preserve the pre-assembly of the first and second parts (2 and 3). Method according to any one of Claims 1 to 3, characterized in that the profiled protruding formation (4), hollow or solid, has a circular, elliptical or rectangular section and in that the or each contact edge (8) has in section a bevelled shape, defining an engagement edge (8') opposing the extraction of the formation (4). Method according to any one of Claims 1 to 4, characterized in that the movement of introducing the protruding formation (4) into the hole (6) is continued until arriving at a position or configuration of stopping or stopper. Method according to claim 5, characterized in that the abutment configuration corresponds to a coming into contact of the wall portion (5) comprising the hole (6) with one or more abutment structures (10) arranged around the base of the protruding formation (4) on the first part (2) and formed in one piece with the latter. Method according to any one of Claims 1 to 6, characterized in that the elastic clamping of the protruding formation (4) in the hole (6) is effective mainly in a given direction (DS), advantageously secant with the longitudinal axis (AL) of the protruding formation (4) and substantially transverse with respect to this axis, said protruding formation (4) being advantageously subjected to a position indexing stress in a direction perpendicular to the aforementioned tightening direction (DS), but preferably with the possibility of play or dispersion in directions perpendicular to the direction (DS). Method according to any one of Claims 1 to 7, characterized in that the hole (6) comprises a single elastically deformable zone (7), situated in the plane of the wall (5), at least in the absence of the protruding formation (4), formed in the edge (6') of the hole (6) and in the form of a tongue obtained by making two similar slots or cutouts (11, 11'), laterally delimiting said tongue (7) and made in the wall portion (5) comprising the hole (6), forming part of the periphery of the latter. Method according to Claim 8, characterized in that the hole (6) has an outline in the shape of the silhouette of a cat's head. Method according to any one of Claims 1 to 7, characterized in that the hole (6) comprises two elastically deformable zones (7 and 7'), configured to receive the protruding formation (4) between them and being in the form of structures forming an integral part of the wall portion (5) and extending prominently over the face (5') of the latter which is opposite to the first part (2), the edges or contact zones (8) of said structures (7 and 7') with the protruding formation (4) being located outside the plane of the wall portion (5) in the absence of deformation. Method according to Claim 10, characterized in that the two elastically deformable structures (7 and 7') come into contact with the protruding formation (4) outside the thickness of the wall portion (5) and consist of two tabs mutually opposite, for example formed in the inner edge (6') of the hole (6) or locally extending the latter. Method according to Claim 11, characterized in that the two tabs (7 and 7') are each delimited by two similar slots or cutouts (11 and 11') made in the wall portion (5) comprising the hole (6) and forming part of the outline (6') of the latter. Method according to any one of Claims 10 to 12, characterized in that the two elastically deformable structures (7 and 7'), preferably two tabs with contact edges (8) in the form of edges or bevelled, advantageously have a configuration in S or Z in section and ensure the holding of the protruding formation (4) in the hole (6), alone or in cooperation with complementary portions (6'') of the internal contour (6') of the hole (6 ). Method according to any one of Claims 1 to 13, characterized in that the quantity of material of the protruding formation (4) intended for the formation of the head (1'') of the rivet (1') is sufficient to cover, and preferentially encapsulating the elastically deformable zone(s) (7, 7') after softening by supplying energy of at least a fraction of the material of the protruding part (4') of the formation (4), preferentially of the entirety of this last part, with a possible filling of the hollow interior of said formation (4) and possible bringing together until contacting of the first and second parts (2 and 3). Method according to any one of Claims 1 to 14, characterized in that each elastically deformable zone (7, 7') is made of a thermoplastic material which is compatible with that constituting the protruding formation (4), the melting operation material by ultrasonic vibrations for the production of the head (1'') of the rivet (1') being continued until the material of the part (4') of the formation (4) is melted and at least a start of fusion of the material of the zone or zones (7, 7'). Method according to any one of Claims 1 to 15, characterized in that at least a third part (12), optionally a wedging or spacer part, is arranged between the first (2) and second (3) parts , during pre-assembly, and is preferably sandwiched tightly between the latter after finalization of the assembly. Method according to any one of Claims 1 to 16, characterized in that the relative positions of the two parts (2 and 3) to be assembled together are determined by additional mechanical indexing means (13, 13'), for example complementary means cooperating by interlocking after the pre-assembly phase, in particular of the orifice-lug type, located close to the hole (6) protruding formation (4) assembly. Assembly point (1) by riveting between two parts (2 and 3), characterized in that it has been obtained by means of the method according to any one of Claims 1 to 17. Composite assembly of at least (2, 3) two parts assembled by riveting, characterized in that it comprises at least one, preferably several, assembly point(s) (1) according to claim 18, obtained via the method according to any one of claims 1 to 17.