Machine for referencing a lap joint and associated welding process

Abstract

Machine for referencing a lap joint and associated welding method The invention relates to an automatic machine involving a fitted assembly having a free external edge 1000 inscribed in a plane P1. The automatic means comprises: - a frame 310, - a stop 32 movable between a retracted position and a reference position in which the stop defines a reference plane P3, - a carriage 33 movable between a loading position and a working position, - a template 34 for positioning and clamping the fitted assembly, - a universal joint 35 capable of pre-positioning the plane P1 parallel to the plane P3. An alignment of the planes P1 and P3 is obtained by automatic movement of the carriage by sliding and friction of the free external edge 1000 on the stop 32. Abstract figure: Figure 4

Description

Title of the invention: Machine for referencing a lap joint and associated welding method Technical field

[0001] The invention relates to an automatic means allowing mechanical referencing of a planar entity relative to a planar stop, the planar entity having an axis. The stop optionally defines a reference point, the referencing allowing in such a case an alignment of the axis of the entity with the reference point. The invention applies in particular to an assembly comprising a first and a second component, the second component being fitted into the first, the fitting defining a shoulder delimited by a lap joint and an edge, the assembly being intended to be welded along the edge. In such an application case, the planar entity corresponds to the shoulder delimited by the lap joint and the welding edge. When the two components are cylindrical, the axis of the planar entity corresponds to the axis of the fitting.

[0002] According to another aspect, the invention relates to an automatic method for referencing a planar entity with a planar stop, optionally including an alignment of an axis of the planar entity with a center of the stop. Such a method can be advantageously used to improve the welding conditions of an assembly formed of two fitted cylindrical components, the fitting defining a weld joint, the method using the automatic means according to the invention, the method typically implementing a torch according to MIG / MAG technology. The invention, which allows referencing of the plane and the center of the joint prior to welding, has the favorable effect of aligning the torch with the welding edge. Such a method can be used in particular for welding tubes and accessories used to guide the gases of an exhaust line of an internal combustion engine. Prior art

[0003] Automatic workshop welding of an assembly consisting of two cylindrical components is commonly carried out by fitting the two components together and positioning and clamping them on a template, the fitted, positioned and clamped assembly defining a lap joint. MIG / MAG technology can be used to carry out the welding. For the needs of large-scale production, the positioned and clamped assembly can be oriented by means of an automatic positioner movable angularly relative to the workshop. The positioner can be a turning device capable of rotating around a working axis. The fitting defines a shoulder delimited internally by a weld joint and externally by a welding edge. A MIG / MAG torch supplying a welding wire is mounted on a robot arm, the torch at the end of the arm being programmed to direct the welding wire towards the welding edge. Automatic welding is carried out by synchronizing the trajectories of the positioner and the robot arm, the welding wire traveling along the welding edge, the weld comprising one or more beads with or without overlap.

[0004] To make welding repeatable to ensure weld quality, it is necessary to control the alignment of the welding wire / electrode with the welding edge.

[0005] However, the lap joint may have variations in position and orientation relative to the welding template and therefore to the positioner. These variations result from the conditions of production of the primary components and the sub-assemblies from which the first component and the second component forming the assembly are derived.

[0006] The first and second components may be tubular and the joint may be inscribed in a plane. In such a case, after positioning and clamping, the fitting has an axis and the joint has a center located at the intersection of the axis and the plane. The two components being tubular, the joint delimits a fitted portion having two thicknesses and an overhanging portion having only one.

[0007] A nominal assembly (in English: "master") consisting of two components produced nominally, themselves positioned and clamped on a template produced according to a digital definition, defines a theoretical fitting and joint, themselves defining a theoretical axis, a theoretical plane and a theoretical center.

[0008] A current assembly taken from a manufacturing batch has geometric variations relative to the 'master' and the position of the current joint can be appreciated by considering the positions of the current plane and the current center relative to the theoretical plane and the theoretical center. These relative positions can be appreciated again by comparing the axial and radial positions of the current center relative to the theoretical center and the angular positions of the current plane relative to the theoretical plane.

[0009] These relative radial, axial and angular positions are the main factors contributing to the misalignment of the torch with the welding edge, the position of the torch at the end of the robot arm being sufficiently repeatable.

[0010] When the lap joints of a population of assemblies have axial, radial and angular relative positions at intervals which result in non-repeatability of the welding, it is known to use a method and means of recalibration by vision. The means uses a light source, typically a laser, and a light sensor, typically a camera. The means is capable of determining the current relative positions of the joint, the determination being able to be carried out by vision of the joint before welding or during welding. A control means gives the robot arm a current re-alignment instruction based on the current relative position. The alignment between the torch and the joint is restored by the re-alignment instruction.

[0011] This first solution has the disadvantage of requiring an incident light source which may be unavailable, for example when the template, given its configuration, obstructs the path of the light.

[0012] When the lap joints of a manufacturing batch have significant axial relative positions, the angular and radial relative positions being limited and without consequence for the welding, it is known to implement a second solution using a mechanical means to axially reference the joint / the welding edge.

[0013] The mechanical means comprises a template, a carriage, a retractable stop, a reversible locking means and an axial turning gear. The carriage is movable in translation along the axis of the turning gear. The locking means allows the carriage to be immobilized relative to the frame, the axis of the fitting being substantially aligned with the axis of the turning gear. The retractable stop defines a line perpendicular to the direction of translation of the carriage. The shoulder and the stop are capable of finding the conditions for at least point contact.

[0014] The method comprises the operations of loading the assembly onto the template, placing the stop, moving the carriage until contact is obtained, immobilizing the carriage by locking and retracting the stop. The result of these operations is a reference setting of the welding edge. Welding is carried out by rotating the turning gear and programming the position of the torch.

[0015] With the torch programmed axially relative to the reference position, there follows a repeatable axial alignment of the current edge with the torch / welding wire / electrode.

[0016] This second solution, although easily automated, is no longer sufficient, particularly when the angular dispersion of the joint plane is significant; such dispersion leads, according to the second solution, to axial flutter during welding which is not tolerated, the axial flutter being the cause of excessive weld penetration / perforation when the torch is directed towards the single thickness and insufficient penetration into the joint when the torch is directed towards the double thickness.

[0017] Thus, the two known solutions described above do not give complete satisfaction.

[0018] The vision registration solution may be rendered unusable due to the configuration of the template which obstructs the path of the light.

[0019] The mechanical solution for axial referencing using a retractable stop can be rendered unusable by excessive angular dispersion of the joint plane as a result of downstream manufacturing steps, such dispersion causing axial flutter. not tolerated by MIG / MAG technology.

[0020] It is finally known that the blocking of the three rotations and the three translations of a mechanical part is sufficient to impose a position and an orientation on it. Such a mechanical part having a flat face, coupled to a flat stop by means of a rotating gimbal and a translating carriage can occupy a state of equilibrium characterized by an alignment of the face and the stop. Such a state of equilibrium is typically obtained by exerting a force on the carriage transmitted to the part and by exerting a counter-force on the part by reaction of the stop to the force. Such an equilibrium position imposes a single orientation of the part relative to the stop, the six degrees of freedom being blocked.Such industrially advantageous referencing poses the problem of possible buttressing of the flat face relative to the stop when automatic movement / translation of the carriage is necessary to automate the referencing. Summary of the invention

[0021] One of the aims of the invention is then to overcome the aforementioned problems.

[0022] To this end, the invention relates to an automatic machine for referencing a fitted assembly,

[0023] the fitted assembly comprising:

[0024] - a first component having a first tubular cylindrical portion, the first tubular cylindrical portion comprising a free external edge which is inscribed in a plane PI,

[0025] - a second component having a second cylindrical portion, said second cylindrical portion being fitted into the first tubular cylindrical portion,

[0026] the automatic machine comprising:

[0027] - an automatic positioner comprising a chassis,

[0028] - an automatic stop retractable relative to the chassis, said stop being movable between a withdrawal position and a reference position, said stop defining, in the reference position, a reference plane P3 repeatable in position relative to the chassis,

[0029] - an automatic trolley movable in translation relative to the chassis between a reverse position and a working position, the direction of translation of the carriage being perpendicular to the reference plane P3,

[0030] - an automatic template configured to position and clamp the fitted assembly,

[0031] - an automatic cardan connecting the template to the carriage, comprising a first member pivoting around a substantially horizontal axis and comprising a return element, and a second pivoting member comprising a pre-positioning element, the return element and the pre-positioning element being capable of pre-orienting the PI plane of substantially parallel to the plane P3 in the recoil position, the fitted assembly positioned and clamped in the template occupying a first state of equilibrium,

[0032] the universal joint being configured so that the fitted assembly occupies a second state of equilibrium in which the planes PI and P3 are merged when the carriage is in the working position,

[0033] the second state of equilibrium being obtained from the first state of equilibrium by automatic movement of the carriage between the recoil position and the working position, by rotation of the pivoting members, and by sliding and friction of the free external edge on the stop.

[0034] Particular characteristics or embodiments, usable alone or in combination, are:

[0035] - the carriage comprises a reversible translation locking means and an acc- tioner, said reversible translation locking means locking / unlocking the translation of the carriage relative to the chassis, the actuator moving the carriage between the recoil position and the working position, the first pivoting member comprises a reversible angular locking means, the second pivoting member has an axis substantially perpendicular to the direction of translation of the carriage and comprises a reversible angular locking means, the reversible angular locking means in combination automatically locking / unlocking the cardan shaft in rotation, and / or

[0036] - the template is movable in rotation relative to the carriage around a point of articulation O of the universal joint, the fitted assembly positioned and clamped in the template defines a fitting axis Al, the axis Al being intersecting with the work plane PI at a work center Cl, the location of the points Cl being in a sliding sphere centered on the articulation point O of the universal joint and of radius equal to five times the positioning error of the point Cl relative to the template, and / or

[0037] - the stop receives a surface treatment promoting sliding of the external edge free relative to the stop, and / or

[0038] - the stop receives a surface and / or core treatment promoting resistance to wear of the stop by relative friction of the free external edge, and / or

[0039] - the template defines a theoretical working axis Alth perpendicular to the plane P3 in the first state of equilibrium, the stop defining in reference position a reference point C3 relative to the chassis, the angular return and angular prepositioning elements being adjustable and pre-aligning the axis Alth with the reference point C3 in the first state of equilibrium, and / or

[0040] - the fitted cylindrical portion of the assembly positioned and clamped in the template defines a repeatable axis Al relative to the template and aligned with the theoretical axis Alth, the assembly has a second cylinder portion extending beyond the first portion cy fitted lindic, the protruding portion of the second cylindrical portion being guided by the stop in the reference position when the universal joint is unlocked, the assembly occupying the first state of equilibrium, and / or

[0041] - the angular pre-positioning element is an angular return element.

[0042] According to a second aspect, the invention relates to an automatic method for referencing a fitted assembly by means of an automatic machine, the fitted assembly comprising: - a first tubular component having a first cylindrical portion, said first tubular cylindrical portion comprising a free external edge inscribed in a plane PI, - a second component having a second cylindrical portion, said second cylindrical portion being fitted into the first tubular cylindrical portion,

[0043] the method implementing: - the automatic machine, comprising: • an automatic positioner comprising a chassis, • an automatic stop retractable relative to the chassis, movable between a retracted position and a reference position, said stop defining, in the reference position, a reference plane P3 repeatable in position relative to the chassis, • an automatic carriage movable in translation relative to the chassis between a recoil position and a working position, the direction of translation of the carriage being perpendicular to the reference plane P3, • an automatic template configured to position and clamp the fitted assembly, • an automatic universal joint connecting the template to the carriage, comprising a first pivoting member around a substantially horizontal axis and comprising a return element, and a second pivoting member comprising a pre-positioning element, the return element and the pre-positioning element being capable of pre-orienting the plane PI in a manner substantially parallel to the plane P3 in the recoil position, the fitted assembly 1 positioned and clamped in the template occupying a first state of equilibrium,

[0044] the universal joint being configured so that the fitted assembly occupies a second state of equilibrium in which the planes P1 and P3 are merged, when the carriage is in the working position,

[0045] the automatic method comprising the following cyclical steps: - obtain the first state of equilibrium, - reference the stop, - obtain the second state of equilibrium,

[0046] the second state of equilibrium being obtained from the first state of equilibrium by automatic movement of the carriage between the recoil position and the working position, by rotation of the pivoting members and by sliding and friction of the free external edge on the stop.

[0047] Particular characteristics or embodiments, usable alone or in combination, are:

[0048] - the carriage comprises a reversible translation locking means and an acc- tioner, said reversible translation locking means locking / unlocking the translation of the carriage relative to the chassis, the actuator moving the carriage between the recoil position and the working position, the first pivoting member comprises a reversible angular locking means and the second pivoting member which has an axis substantially perpendicular to the direction of translation of the carriage further comprises a reversible angular locking means, the reversible angular locking means in combination automatically locking / unlocking the gimbal in rotation, the method comprising an automatic loading step prior to the step of obtaining the first state of equilibrium in which the carriage occupies the recoil position, the carriage is locked in translation by the means, the gimbal is locked in rotation by the means and the fitted assembly is positioned and clamped on the template, and / or

[0049] - the carriage comprises a reversible translation locking means and an acc- tioner, said reversible translation locking means locking / unlocking the translation of the carriage relative to the chassis, the actuator moving the carriage between the recoil position and the working position, in which the first pivoting member comprises a reversible angular locking means and in which the second pivoting member has an axis substantially perpendicular to the direction of translation of the carriage, further comprises a reversible angular locking means, the reversible angular locking means in combination automatically locking / unlocking the cardan joint in rotation, the method comprising a step of engaging the work subsequent to the step of obtaining the second equilibrium state in which the carriage occupies the working position, the carriage is locked in translation by the means, the cardan joint is locked in rotation by the means, the fitted assembly being positioned and clamped on the template, and / or

[0050] - a step of pre-assembly of the first and second components and is carried out prea probably at the stage of obtaining the first equilibrium state, and / or

[0051] - the pre-assembly step is a crimping, in which the template defines an axis theoretical Alth and in which the crimping is carried out by isostatic positioning of the component according to external bearing surfaces SI, the fitted cylindrical portion of the assembly after crimping defining a repeatable axis Al relative to the bearing surface SI, the repeatable axis Al being aligned with the theoretical axis Alth when the assembly is positioned and clamped on the template according to the bearing surfaces SI, and / or

[0052] - the machine is a welding installation and a welding step is consecutive of the work engagement stage, and / or

[0053] - the welding installation comprises a welding head defining an axis A4, in in which the stop in the reference position defines a center C3 and in which the positioner rotates the chassis around an axis A2 perpendicular to the plane P3 and passing through the center C3, the welding step being carried out by aligning the axis A4 with the planes PI and P3 combined and by rotating the chassis around the axis A2. Brief description of the drawings

[0054] The invention will be better understood on reading the following description, given solely by way of example, and with reference to the appended figures in which:

[0055] [Fig-1] shows a crimped fitted assembly,

[0056] [Fig.2] shows a crimping means,

[0057] [Fig.3] shows a welding means,

[0058] [Fig.4] shows the welding means which is a means of referencing,

[0059] [Fig.5] shows an angular recall element,

[0060] [Fig.6] shows a first equilibrium state of a group, and

[0061] [Fig.7] shows welding conditions of the assembly. Description of the embodiments

[0062] With reference to [Fig.l], and according to a preferred embodiment, an assembly 1 comprises a first tubular component 10 and a second component 11.

[0063] The first tubular component 10 has a first cylindrical portion 100 of revolution, said first cylindrical portion 100 having a substantially planar and circular fitting end 100a. The first tubular component 10 may also comprise a sleeve 101 mounted on the inner surface of the first cylindrical portion 100, said sleeve 101 having a planar boundary 101a set back, tangent or projecting relative to the planar end 100a, the intention being to obtain a planar boundary 101a merged in the plane of the planar end 100a. Whatever the configuration, the planar end 100a and the planar boundary 101a define a free external edge 1000. Thus, when the planar boundary 101a is set back relative to the planar end 100a, the free external edge 1000 is merged with the edge of the planar end 101a.Conversely, when the plane boundary 101a is relatively overhanging the plane end 100a, the edge 1000 is merged with the edge of the . planar boundary 100a. When the planar boundary 101a has an overhanging portion and a complementary portion set back relative to the planar end 100a, the free external edge 1000 is composed of the edges of the complementary overhanging portions of the planar end 100a and the planar boundary 101a.

[0064] Whatever the configurations, the edge 1000 is inscribed in a fitting plane PI.

[0065] The sleeve 101 is typically made integral with the first cylindrical portion of the component 10 by insertion, radial expansion then spot welding, the spot welds which secure the sleeve 101 to the first cylindrical portion 100 being spaced from the edge 1000 so as not to disturb the MIG / MAG welding operation according to the invention.

[0066] The first cylindrical portion 100 and the coaxial sleeve 101 define a fitting axis A10.

[0067] The intersection of the fitting plane PI with the fitting axis A10 defines a fitting center CIO.

[0068] The first component 10 comprises for example a hook 102 and a body 103, the hook having bearing surfaces 102a, 102b. The surface 102a is inscribed in an oblong cut out of the hook 102 and the surface 102b is inscribed in a face of the hook 102. The body 103 has flat bearing surfaces 103a, 103b stamped in the inlet cone of the body 103.

[0069] The component 10 is pre-assembled so as to obtain a repeatable orientation of the fitting axis A10. This results in a precise radial location of the center CIO relative to the surfaces 102a, 102b, 103a, 103b. For this purpose, the pre-assembly is for example carried out by positioning the hook 102 according to a first isostatism which uses the surfaces 102a, 102b and by positioning the body 103 according to a second isostatism which uses the center CIO and the surfaces 103a, 103b. A shouldered bushing mounted on a spring and cooperating with the tubular cylindrical portion 100 typically guides the fitting axis A1 over a short length. According to such a preassembly, surfaces of the components 102 and 103 in mutual contact are added to the surfaces 102a, 102b on the one hand and 103a, 103b on the other hand to create the conditions for isostatism of the hook 102 and the body 103.

[0070] Such a preparation radially locates the CIO center relative to the surfaces 102a, 102b, 103a, 103b according to a tolerance typically equal to 0.6 mm.

[0071] These pre-assembly conditions leave the orientation of the edge 1000 free relative to the reference surfaces 102a, 102b, 103a and 103b. The orientation defect of the external edge 1000 relative to the surfaces 102a, 102b, 103a, 103b can reach the value of 2.0 mm to which is added a positioning defect along the axis A10.

[0072] The pre-assembly of the hook 102 and the body 103 is typically carried out by MIG / MAG welding.

[0073] After pre-assembly, the surfaces 102a, 102b, 103a, 103b in combination can be used for isostatic positioning of the first component 10.

[0074] In an exemplary embodiment, the second component 11 is tubular. It has a second cylindrical portion 110 of revolution defining a second fitting axis A1 1. It comprises a tube 111 and a flange 112, the tube 111 comprising the second cylindrical portion 110, the flange 112 having reference surfaces 112a, 112b, 112c belonging respectively to a first bore, a second bore and a joint plane.

[0075] The second component 11 is pre-assembled so as to position the axis Ail precisely relative to the group of surfaces 112a, 112b, 112c. For this purpose and during pre-assembly, the tube 111 is positioned according to a third isostatism which uses a theoretical axis Al Ith and the flange 112 according to a fourth isostatism which uses the group of surfaces 112a, 112b, 112c. Contact surfaces common to the tube 111 and to the flange 112 are added to the 2 groups of surfaces to create the conditions of the third and fourth isostatism during pre-assembly. A sleeve receiving the cylindrical portion 110 over its entire length can define the theoretical axis Al Ith.

[0076] Prior to pre-assembly, a pre-existing clearance between the tube 111 and the flange 112 can be cancelled by means of a radial expansion operation creating the conditions for obtaining contact surfaces common to the tube 11 and the flange 112.

[0077] Such conditions of the pre-assembly of the second component 11 locate the axis Ail relative to the surface group 112a, 112b, 112c according to a tolerance value typically equal to 0.6 mm.

[0078] The assembly of the tube 111 and the flange 112 is carried out for example by MIG / MAG welding.

[0079] The first component 10 and the second component 11 are for example manufactured from ferritic, austenitic or duplex stainless steel, typically from 1.4509 ferritic sheet and 1.4511 ferritic casting. The first and second components 10, 11 may be of thin thickness, i.e. having a thickness of between 0.6 mm and 1.0 mm or thicker, i.e. having a thickness of between 1.2 mm and 2.5 mm, for example.

[0080] The thickness of the sleeve 101 is typically between 1.0 mm and 2.5 mm, for example is 1.0 mm.

[0081] The diameters of the first and second components 10, 11 in the fitting zone are for example between 40 mm and 80 mm when the intended application is an exhaust line for light vehicles. The diameters are greater than 80 mm when the intended application is an exhaust line for commercial vehicles.

[0082] In a particular embodiment, notably shown in FIGS. 1 and 2, the first and second components 10, 11 are pre-assembled. The assembly 1 comprising the pre-assembled first and second components 10, 11 is obtained by crimping the first component 10 onto the second component 11 following a preliminary step using a crimping means 2.

[0083] The crimping means 2 comprises a crimping template 21. After fitting, an isostatic positioning of the first component 10 is obtained using the surfaces 102a, 102b, 103a, 103b. An isostatic positioning of the second component 11 is obtained using the surfaces 112a, 112b, 112c.

[0084] The crimping means 2 also comprises a set of jaws 22 capable of radially and plastically crimping the first component 10 onto the second component 11, the crimping location being repeatable relative to the surfaces 102a, 102b, 103a, 103b, 112a, 112b, 112c.

[0085] Before crimping, several conditions are met:

[0086] - the fitting axis A10, the work center CIO, the second axis fitting Ail are substantially aligned taking into account the location defects of the axis A10 relative to the group of surfaces 102a, 102b, 103a, 103b and of the axis Ail relative to the group of surfaces 112a, 112b, 112c,

[0087] - the surfaces 112a, 112b, 112c are positioned nominally relative to the group of surface 102a, 102b, 103a, 103b.

[0088] After crimping, results are obtained, some of which are advantageous:

[0089] - the sleeve 101 increases the clamping force and the risk of relative slippage of the first and second components 10, 11 are eliminated. The fitted and crimped assembly 1 is therefore suitable for handling, particularly when the first component 10 is of low thickness,

[0090] - the surface group 102a, 102b, 103a, 103b can advantageously serve as a surface reference to create the conditions for isostatism of the set 1 fitted and crimped,

[0091] - the crimped assembly 1 has a crimped fitted portion 12 which defines an axis of work Al, the working axis Al being located radially in a precise manner relative to the reference surface 102a, 102b, 103a, 103b, the effect of the elastic return following the crimping being negligible,

[0092] - the working axis Al is located relative to the surface 102a, 102b, 103a, 103b ty stitching according to a tolerance value of 0.3 mm, lower than that corresponding to the A10 axis of the first raw welded component.

[0093] - after crimping, the edge 1000 fits into a working plane PI,

[0094] - the axis Al and the plane PI define by intersection a work center Cl,

[0095] - the crimped fitted portion 12 and the edge 1000 define a shoulder 13,

[0096] - the crimped fitted portion 12 has a thickness for example between 1.6 mm and 4.0 mm, preferably equal to 1.8 mm.

[0097] - the meeting line between the work plane PI and the second cylindrical portion 110 defines a lap joint 14, the clearance between the first cylindrical portion 100 and the second cylindrical portion being less than 0.2 mm at the right of the lap joint 14,

[0098] After crimping, the location defect of the shoulder 13 can reach the value of 3.0 mm relative to the reference surface 102a, 102b, 103a, 103b.

[0099] Such a localization defect is the consequence of the angular dispersion of the free external edge 1000 relative to the theoretical working axis Al and of the localization defect of the center Cl relative to this same theoretical working axis Al.

[0100] Such a localization defect increases drastically with the diameters of the cylindrical portions 100 and 110.

[0101] With reference to figures 1, 3, 4 and 5 and according to a preferred embodiment, a welding installation 3 comprises an automaton not shown, a welding head 30, a positioner / turner 31, a retractable stop 32, a mobile carriage 33, a welding template 34, a universal joint 35.

[0102] The automaton makes it possible to control the actions of the welding head 30, the positioner 31, the retractable stop 32, the carriage 33, the welding template 34, the gimbal 35 according to a time line specific to a unit manufacturing cycle comprising a reference setting and a welding.

[0103] The automatic template 34 is configured to position and clamp the fitted assembly 1.

[0104] The free external edge 1000 of the fitted assembly 1 is inscribed in the plane PL

[0105] The automated welding head 30 is typically manipulated by a robot comprising six or seven axes. The welding head comprises MIG / MAG technology, one advantage of which is productivity and relative tolerance.

[0106] the automatic machine 3 comprises an automatic positioner 31, itself comprising a chassis 310.

[0107] The chassis 310 can be fixed or mobile relative to the workshop.

[0108] When the chassis 310 is mobile, the automated positioner 31 may be a turning device capable of rotating the chassis 310 around an axis A2 relative to a frame 311, said frame 311 being fixed relative to the workshop.

[0109] The automatic stop 32 is retractable relative to the chassis 310, said stop 32 being movable between a retracted position and a reference position, said stop defining, in the reference position, a reference plane P3 repeatable in position relative to the chassis 310.

[0110] The automated retractable stop 32 typically comprises a set of stops 320 and a retraction mechanism not shown, making it possible to assist the change of position of the stop set, the stop set selectively moving from a retracted position to a reference position.

[0111] The set of stops 320 comprises for example two first surfaces 320a which define in reference position and in tangency a reference plane P3. The plane P3 is opposite the plane of the free external edge 1000 when the assembly 1 is positioned and clamped in the template 34.

[0112] The plane P3 is perpendicular to the axis A2 of the turning gear 31.

[0113] The set of stops also comprises second surfaces 320b which define in reference position and in common zone a reference center C3. The referencing means 3 is designed so that the reference center C3 belongs to the axis A2.

[0114] The retraction mechanism comprises a fixed portion and a movable portion, the stopper set 320 being fixed to the movable portion. The retraction mechanism is configured to position the stopper set 320 repeatably relative to the frame 310.

[0115] According to a first variant, the fixed part of the retraction mechanism is embedded in the chassis 310 and the mobile part has a positioning tolerance under force sufficient to ensure the repeatability of the positioning of the set of stops 320.

[0116] According to another variant, the fixed part is linked to the reference frame defined by the workshop. The chassis 310 may comprise a double form and the mobile part of the retraction mechanism a double counter form, the double form and the double counter form being able to fit together and index each other. A flexible / compliant connection may typically be added between the counter form and the mobile part. In the fitted and indexed state, the form and the counter form impose a repeatable working position of the stop set 320 relative to the chassis 310.

[0117] The automated carriage 33 is movable in translation relative to the chassis 310 between a recoil position and a working position. The translation direction X of the carriage is typically perpendicular or substantially perpendicular to the reference plane P3. It comprises a first reversible locking means 330. The reversible locking means 330 is for example a brake actuated by a linear actuator, such as a double-acting pneumatic cylinder connected to a valve itself electrically controlled by the automaton.

[0118] In a particular embodiment, the mobile carriage 33 also comprises an actuator 331, a rail 332 and a shuttle 333, the rail 332 and the shuttle 333 performing the slide function. The rail 332 fixed to the frame 310 constrains the shuttle 333 to move in a direction of movement X that is horizontal or inclined relative to the horizontal. The rail also comprises a rear stop, not shown. The actuator 331 makes it possible to move the shuttle in a forward direction or in a return direction by exerting an adjustable force F, the movement of the shuttle 333 in the return direction being stopped by the rear stop. The actuator 331 is typically a linear actuator, such as a double-acting pneumatic cylinder connected to a valve electrically controlled by the automaton. The cylinder is sized to produce a force capable of moving the shuttle 333, the universal joint 35, the welding template 34 and the assembly. It is capable of opposing the friction forces linked to the operation of the referencing means 3. The useful stroke of the cylinder is for example between 1 and 2 cm.

[0119] The blocking of the translation of the carriage 33 after a forward or return movement is obtained by actuating the first reversible locking means 330.

[0120] The unlocking of the translation of the carriage 33 before a forward or return movement is obtained by releasing the first reversible locking means 330.

[0121] The gimbal 35 connects the template 34 to the carriage 33.

[0122] The automatic universal joint 35 comprises a first pivoting member 351 about a substantially horizontal axis and which comprises a return element 3510 and a second pivoting member 352 which comprises a pre-positioning element 3520, the return element 3510 and the pre-positioning element 3520 being capable of pre-orienting the plane PI in a manner substantially parallel to the plane P3 in the recoil position.

[0123] The gimbal 35 is therefore movable in rotation relative to the shuttle 333 along a substantially horizontal Y axis by means of the first pivoting element 351.

[0124] It is typically rotated along a Z axis substantially perpendicular to the X direction by means of the second pivoting element 352.

[0125] The X direction and the Y, Z pivot axes typically form a right trihedron.

[0126] The Z axis can be vertical if the frame 310 imposes an orientation of the X axis ho front before starting the work / welding operation.

[0127] The Z axis may be tilted if the frame 310 is tilted relative to the horizontal to facilitate engagement of the welding work / operation.

[0128] Each pivoting element 351, 352 typically comprises a rotating shaft and a bearing.

[0129] The first pivoting element 351 comprises the angular return element 3510 which opposes the incident torques exerted on the assembly 1 positioned and clamped on the template 34 along the Y axis.

[0130] The angular return element 3510 pre-orients the positioned and clamped assembly 1 around the Y axis in the pitch direction. The pre-orientation can be adjusted when the return element comprises an adjustment means such as adjustment screws 35100a and 35100b mounted in opposition.

[0131] The first pivoting element 351 comprises a reversible locking means 3511 capable of blocking / unblocking the rotation of the gimbal 35 around the Y axis in the pitching direction.

[0132] The second pivoting element 352 comprises an angular pre-positioning element 3520 which pre-orients the gimbal 35 along the Z axis in the yaw direction.

[0133] According to a first variant, the pre-positioning element may consist of 2 angular stops retractable between a pre-positioning position and a working position. In the pre-positioning position, the 2 stops limit the rotation of the gimbal 35 in yaw. In the working position, the angular movement of the gimbal 35 in the yaw direction is free.

[0134] According to a second variant, the angular pre-positioning element 3520 is an angular return element operating on the principle of the first pivoting element 351.

[0135] The second pivoting element 352 comprises a reversible locking means 3521 capable of blocking / unblocking the rotation of the gimbal 35 around the Z axis in the yaw direction.

[0136] With reference to [Fig.5], the angular return element 3510 integrates an adjustment function intended to pre-orient the template 34 relative to the chassis 310 and to the reference plane P3 around the Y axis. The return element 3510 is similar to a pitch corrector.

[0137] In a preferred embodiment and in the remainder of the description, the angular pre-positioning element 3520 is an angular return element.

[0138] The angular return element 3520 also integrates an adjustment function intended to pre-orient the template 34 relative to the chassis 310 and to the reference plane P3 around the Z axis. The return element 3520 is similar to a yaw corrector.

[0139] The pitch and yaw correctors 3510, 3520, respectively comprise pairs of compression and opposition springs 35100a,b and 35200a,b, cams 35101, 35201 secured to the shafts 3512, 3522 of the first and second pivoting members and pairs of adjustable rear stops 3520la,b and 35202a,b. The adjustable rear stops 3520la,b and 35202a,b are respectively connected to bearings of the pivoting members 351, 352. Each of the cams 35101, 35102 has two flat faces extending radially relative to the axis of each of the pivots. Each of the springs of pairs 35100a,b and 35200a,b has two ends bearing respectively on one of the adjustable stops and on one of the two faces of the cams 35101,35102.

[0140] The adjustment arrangements of the pitch and yaw correctors 351, 352 allow pre-orientation of the group 36 formed by the assembly 1 and the welding template 34 relative to the chassis 310.

[0141] The distance of the cam from the pivot axis, the dimensioning of the springs 35100a,b and 35200a,b and their respective compression determine torques around the pivot axes Y,Z capable of correcting the orientation of the template 36 in the direction of pitch or yaw.

[0142] The compliant arrangements of the pitch and yaw correctors give the group 36 an angular flexibility / stiffness making it suitable for angular displacements around the Y and Z axes and therefore around the articulation point O under the effect of an incident moment.

[0143] Thus, after adjustment of the rear stops 35102a,b and 35202a,b, the group 36 occupies a first state of equilibrium characterized by an adjustment angle Q1Y along the Y axis and an adjustment angle Q1Z along the Z axis.

[0144] Under the effect of resultants of additional moments (MY) and (MZ) brought into play during the different stages of the process, the angles QY and QZ evolve and reach values ​​QNY and QNZ associated with a series N of equilibrium states.

[0145] The pitch corrector 351 imparts RTY stiffness to the group 36 along the Y axis.

[0146] The yaw corrector 352 imparts an RLZ stiffness to the group 36 along the Z axis.

[0147] Thus, the additional moments can be written:

[0148] (MY) = RTY x (QNY - Q1Y) and (MZ) = RLZ x (QNZ - Q1Z).

[0149] The welding template 34 fixed to the gimbal 35 itself fixed to the carriage 33 is therefore suitable to be moved in rotation and translation relative to the chassis 310.

[0150] The welding template 34 comprises receiving surfaces 3411 configured to receive the support surfaces 102a, 102b belonging to the hook 102 of the first component 10 and therefore of the crimped fitted assembly 1.

[0151] The welding template 34 also comprises receiving surfaces 3412 configured to receive the support surfaces 103a, 103b belonging to the body 103 of the first component 10 and therefore of the fitted and crimped assembly 1.

[0152] The positioning of the crimped, fitted assembly 1 according to the bearing surfaces 102a, 102b, 103a, 103b is isostatic.

[0153] The receiving surfaces 3411, 3412 form in combination the receiving surface 341 capable of receiving the support surfaces 102a, 102b, 103a, 103b, the assembly 1 being positioned isostatically.

[0154] The template can also include pneumatic clamps controlled by the automaton which allow clamping of the assembly 1 after positioning.

[0155] With reference to figures 1, 3, 4, 6 and 7, a welding method is implemented to weld the assembly 1 using the referencing means 3 according to the preferred embodiment, the first component 10 and the second component 11 being preassembled by crimping.

[0156] The referencing means 3 comprises the positioner 31, the retractable stop 32, the mobile carriage 33, the mobile platform 34 and the welding jig 35.

[0157] A welding device not shown using a welding head 30 completes the installation 3.

[0158] The method comprises, during a given cycle, the following automatic steps:

[0159] - a step consisting of putting the stop 32 in the retracted position and the carriage 33 in recoil position, the translation of the carriage 33 and the rotations of the gimbal 35 being blocked respectively by the reversible locking means 3511, 3521.

[0160] - a step consisting of positioning and clamping the assembly 1 fitted onto the template welding 34, the assembly 1 positioned and clamped defining the work plane PI, the work axis Al and the work center Cl, the work center Cl being substantially merged with the articulation point O of the universal joint 35,

[0161] - a step consisting of unlocking the gimbal 35 in rotation, the assembly 1 occupying a first equilibrium state, the first equilibrium state pre-positioning the plane PI parallel to the plane P3, the parallelism condition being obtained on average over a manufacturing batch. According to the preferred manufacturing method implementing a pre-assembly of the components 10 and 11 by crimping, the axis Al is positioned in a repeatable manner relative to the surfaces 102a, 102b, 103a, 103b and therefore relative to the receiving surfaces 341 of the template 34. Thus, the axes Al of a manufacturing batch are aligned with a theoretical axis Alth of the template 34. The adjustment arrangements of the universal joint 35 are used to pre-align the axis Alth with the center C3 of the stop in the reference position. The assembly 1 in the example has a second fitted portion 110 projecting beyond the first cylindrical portion 100.The axis Al being directed towards the center C3, the stop 32 is configured to cooperate radially with the overhanging portion 1100 along the axis Alth, when the assembly 1 occupies the first equilibrium state and the stop 32 is in the reference position. According to such a configuration, the portion 1100 is able to slide during the translation of the carriage along the stop 32 in the reference position.

[0162] - a step consisting of unlocking the translation of the carriage 33 by releasing the first reversible locking means 330 then to exert a force F on the carriage 33, the carriage 33 and the assembly 1 moving towards the stop 32 along the axis X. the stop can be configured to cooperate axially with the end 1000. Taking into account the configuration of the stop 32 and the axis Al aligned with the axis Ath and directed towards the center C3, the overhanging portion 1100 slides along the stop 32.

[0163] - a step of simultaneously sliding the overhanging portion 1100 along of the stop 32 and the end 1000 to the surface of the stop 32, the stop being in the reference position.

[0164] - a step consisting of blocking the translation of the carriage 33 with the first means of reversible lock 330, and to lock the rotations of the gimbal 35.

[0165] - a step consisting of putting the stop 32 in the retracted position.

[0166] - a step of welding by bringing the welding head 30 into alignment of the edge 1000 which is a welding edge, for example using MIG / MAG technology.

[0167] A preferred mode of implementation of the method is described in the following:

[0168] The frame 310 has a double shape and the stop 32 has a fixed part and a moving part, the moving part comprising a double counter-form, not shown, capable of being indexed and fitted with the double form of the chassis 310.

[0169] A flexible / compliant connection between the fixed part and the movable part of the stop 32 allows the double form and double counter form to fit together and index each other.

[0170] In the reference position, the double form and the double counter form are embedded and indexed.

[0171] To obtain the withdrawal position, the stop clearance 320 is retracted, the double counterform being released from the double embedding and the double indexing.

[0172] The movable portion is typically configured to move the stop set 320 away from the workspace in the retracted position, whereby potential interference between the welding head 30 and the stop set 320 is eliminated.

[0173] During a previous cycle, the actuator 331 moved the carriage 33 to the reverse position.

[0174] Before loading the assembly 1 onto the template 34, the first reversible locking means 330 blocks the translation of the carriage 33 and the reversible locking means 3511, 3521 block the 2 pivot connections of the universal joint 35.

[0175] To obtain the loading state, the assembly 1 is positioned manually or automatically on the welding template 35. The bearing surfaces 102a, 102b, 103a, 103b of the assembly 1 are brought into contact with the receiving surfaces 3411, 3412. The assembly 1 is clamped manually or automatically and the clamping can be confirmed automatically.

[0176] Set 1 defines the work plane PI, the work axis Al and the work center Cl relative to the template 34.

[0177] The assembly 1, the welding template 34 are configured so that the work center C1 is substantially coincident with the articulation point O. Such a configuration minimizes / cancels the values ​​of the moments associated with the friction forces of the external edge 1000 on the stop 32 whose action opposes the alignment of the planes P1 and P3. Such a technical effect is described in detail in the rest of the text.

[0178] The free external edge 1000 of the shoulder 13 is a welding edge.

[0179] To pre-position the free external edge 1000 and the overhanging portion 1100 rela tively at the stop 32, the universal joint 35 is unlocked, the resultants of the moments exerted respectively around the pivot axes Y and Z being zero, the assembly 1 occupying a first state of equilibrium.

[0180] Along the Y axis, the first equilibrium state involves a moment GY 1 associated with a vertically directed gravity force fgy, applied to the center of gravity of the group 36 and at a distance dgy from the Y axis.

[0181] The first equilibrium state also involves a moment MY1 exerted by the pitch corrector 3510 in reaction to the moment GY1.

[0182] The moment MY1 is the resultant of the moments (MY11, MY12) exerted by the two opposing springs 35100a, b.

[0183] Along the pivot axis Z, the first state of equilibrium involves a torque MZ1 exerted by the yaw corrector 3520 on the group 36. The torque MZ1 is the resultant of the moments (MZ11, MZ12) exerted by the two opposing springs 35200a, b.

[0184] In the first equilibrium state, the group 36 is finally subjected to the torque (GY1, MY 1) along the Y axis and to the torque (MZ11, MZ12) along the Z axis.

[0185] The pitch corrector 3510 and the yaw corrector 3520 are adjusted so that the working axis A1 is aligned with the reference point C3.

[0186] The repeatable orientation of the axes Al relative to the receiving surfaces 3411, 3412 and their alignment with the axis Alth of the template 34 makes this adjustment possible.

[0187] The pre-positioning of the edge 1000 and the overhanging portion 1100 relative to the stop 32 also includes placing the stop 32 in the reference position.

[0188] The stop which typically comprises a stop clearance 320 has in the reference position a passage section 320a defining in its center the reference point C3 and a surface 320b opposite the edge 1000 defining in tangency the reference plane P3.

[0189] When placing the stop 32 in the reference position, the stop clearance 320 and the overhanging portion 1100 of the assembly 1 may be in a state of interference then in a state of cooperation if the axis A1 is not repeatable relative to the prepositioned template 34.

[0190] By interference state, it is understood that a temporary or continuous contact between the overhanging portion 1100 and the stop clearance occurs when the stop 32 is referenced.

[0191] By state of cooperation it is understood that the axis Al aligns with the center C3, the section 320b being dimensioned relative to the overhanging portion 1100 so that a clearance is established, the stop 32 and the assembly being mechanically linked by guidance and not by embedding.

[0192] The overhanging portion 1100 and the stop 32 can be directly in a state of cooperation if the axis Al is repeatable relative to the template 34 and the template 34 is prepositioned so as to align the axis Alth with the center C3.

[0193] The stop clearance 320 and the overhanging portion 1100 by interfering and then cooperating modify the torque values ​​relative to the Y and Z axes by modifying the compression of the springs 35100a,b and 35200a,b.

[0194] The stop clearance 320 and the overhanging portion cooperate directly without interfering do not change the torque values ​​relative to the Y and Z axes.

[0195] In all cases, the group 36 finds, after referencing the stop 32, occupies an intermediate equilibrium state characterized by torque values ​​(GY2, MY2) and (MZ21, MZ22).

[0196] The intermediate equilibrium position is in practice little different from the first equilibrium position and the torque values ​​(GY1, MY1) (GY2, MY2) and (MZ11, MZ12) (MZ21, MZ22) are substantially identical.

[0197] The torque values ​​(GY1, MY1) (GY2, MY2) and (MZ11, MZ12) (MZ21, MZ22) are equal when the overhanging portion 1100 cooperates perfectly with the stops 32 and / or the axis Al merged with the theoretical axis Alth is aligned with the center C3.

[0198] To obtain such cooperation, the stop 32 has, for example, a substantially square passage section.

[0199] Generally, the passage section of the stop 32 is sized to facilitate the engagement of the overhanging portion 1100 relative to the stop 32 in the interference state.

[0200] The section of the stop 32 is also dimensioned in order to guide the overhanging portion 1100 in the state of cooperation.

[0201] The section of the stop is further dimensioned with the aim of obtaining optimal clearance with the overhanging portion 1100, the optimal clearance having the function of guiding and positioning the surface 1100 in the state of cooperation.

[0202] The stop 32 can be chamfered according to the passage section to guide the overhanging portion 1100 around the center C3 in the state of cooperation.

[0203] Thus, the overhanging portion 1100 retains freedom of rotation around the Y and Z axes in the cooperative state.

[0204] Optionally, the set of stops 320 is chamfered along the faces / edges 320b of the stop in the reference position.

[0205] The stop game may include reinforcements.

[0206] The stop game 320 is for example made of hardened and tempered steel.

[0207] The stop game 320 has for example received a nitriding treatment on its surface.

[0208] The 2 stops of the game 320 can index each other by a mortise and tenon system so that their faces 320a opposite the free external edge 1000 are perfectly merged in the same plane.

[0209] In a particular embodiment, the working center Al is located less than 1 cm from the reference plane P3 when the assembly 1 occupies the first equilibrium state.

[0210] In another embodiment, the work center A1 is located at a distance from the reference plane P3 equal to at most the length of the overhanging portion 1100 when the assembly 1 occupies the first equilibrium state.

[0211] Finally, in the first equilibrium state, the set 1 whose overhanging portion 1100 cooperates with the faces / edges 320b of the stop set 320, has a working plane PI pre-aligned on average over a manufacturing batch with the plane P3.

[0212] The universal joint 35 is configured so that the fitted assembly 1 occupies a second state of equilibrium in which the planes P1 and P3 are merged when the carriage 33 is in the working position,

[0213] Furthermore, the second state of equilibrium is obtained from the first state of equilibrium by automatic movement of the carriage 33 between the recoil position and the working position, by rotation of the pivoting members 351, 352 and by sliding and friction of the free external edge 1000 on the stop 32.

[0214] To obtain the second state of equilibrium, a force F is typically exerted on the carriage 33, the group 36 and therefore the assembly 1 moving in a forward direction towards the stop 32 in the reference position.

[0215] During the movement, the section of the stop 32 guides the overhanging portion 1100 of the assembly 1, the conditions of alignment of the working axis A1 with the center C3 being consequently maintained.

[0216] At an instant ti of the movement, the edge 1000 comes into contact at least punctually with the surface 320a.

[0217] At time ti and after, the group 36 transmits a force F on the stop 32 by producing a force vector fn normal to the surface 320a and a force vector ft parallel to the surface 320a, the 2 force vectors fn and ft evolving along a time line t.

[0218] In reaction to the force F, the stop 32 exerts a counter force CF on the group 36 by producing a force vector cfn normal to the surface 320a and a force vector cft parallel to the surface 320a, the 2 force vectors cfn and cft evolving along the time line t.

[0219] The force vectors (fn, ft, cfn, cft) apply at a common point / midpoint of a common surface P belonging to the surface 320a, the location of the point / midpoint P evolving along the time line t.

[0220] At time ti and after, torques (MnY, CMnY), (MtY, CMtY), (MnZ, CMnZ), (MtZ, CMtZ) relative to the Y and Z axes and associated with the force vectors (fn, ft, cfn, cft) are exerted simultaneously on the stop 32 and the group 36. The moments CMnY, CMtY, CMnZ, CMtZ which are exerted specifically on the group 36 are a function of the respective values ​​[fn], [ft], [cfn], [cft] and the respective distances dnY, dtY, dnZ, dtZ of these force vectors relative to the Y and Z axes.

[0221] At time ti and after, group 36 is subjected along the Y axis to moments CMnY, CMtY, MY, GY.

[0222] The moment CMnY which is a function of [cfn] and dnY directs the rotation of group 36 in the direction of alignment of plane PI with plane P3.

[0223] The moment CMtY which is a function of [cft] and dtY opposes the rotation of the group 36 in the direction of alignment of plane PI with plane P3.

[0224] The resultant (MY, GY) is a function of the angular stiffness RTY of the pitch corrector 3510 and the angular displacement (QY-Q1Y) of the group 36 relative to the first equilibrium state. It opposes the rotation of the group 36 in the direction of alignment of the plane PI with the plane P3.

[0225] The angular stiffness RTY is substantially constant and the angular displacement (QY-Q1Y) of the group 36 relative to the first equilibrium state along the Y axis is limited in value.

[0226] The resultant (MY, GY) is also bounded in value.

[0227] At time ti and after, group 36 is subjected along the Z axis to moments CMnZ, CMtZ, MZ.

[0228] The moment CMnZ is a function of [cfn] and dnZ. The moment CMnZ directs the rotation of group 36 in the direction of alignment of the plane PI with the plane P3.

[0229] The moment CMtZ is a function of [cft] and dtZ. The moment CMtZ opposes the rotation of group 36 in the direction of alignment of the plane PI with the plane P3.

[0230] The torque MZ is a function of the angular stiffness RLZ of the yaw corrector 3520 and the angular displacement (QZ-Q1Z) of the group 36 relative to the first equilibrium state along the Z axis. The torque MZ opposes the rotation of the group 36 in the direction of alignment of the plane PI with the plane P3.

[0231] The angular stiffness RLZ is substantially constant and the angular displacement (QZ-Q1Z) of the group 36 relative to the first equilibrium state along the Z axis is limited in value.

[0232] The MZ couple is also limited in value.

[0233] To create the conditions for alignment of the work plane PI with the reference plane P3, it is sufficient that at time ti the moments CMnY and CMnZ are simultaneously greater than the resultants (CMtY, MY, GY) and (CMtZ, MZ).

[0234] Otherwise, the edge 1000 butts against the surface 320a of the stop clearance 320.

[0235] Between ti and tf, the forces cfn and cft are in a ratio depending on the properties of dynamic or static friction characterizing the contact between the edge 1000 and the surface 320a.

[0236] At time tf and after, the forces cfn2 and cft2 are in a ratio dependent on the static friction properties characterizing the contact between the edge 1000 and the surface 320a.

[0237] Thus, if the sliding conditions are satisfied at time ti, the sliding continues until time tf where the plane PI aligns with the plane P3, the contact properties not changing between ti and tf.

[0238] According to a preferred embodiment, the working center C1 is included in a sliding sphere centered on the articulation point O of the gimbal 35 whose radius is equal to the location defect of the center Cl relative to the template 34.

[0239] Thus, according to the preferred embodiment, the lever arms dtY and dtZ are null or almost null. The moments CMtY and CMtZ are null or almost null and the resultants (CMtY, MY, GY) and (CMtZ, MZ) are bounded in value.

[0240] To create the conditions for an alignment of the planes PI and P3, it is sufficient to increase the value of the force F in a necessary and sufficient manner. Thus, the value of the counter force CF and therefore the value of the normal component cfn and also consecutively the values ​​of CMnY and CMnZ, exceed respectively those of the resultants (CMtY,MY,GY) and (CMtZ,MZ) which are limited.

[0241] In practice, the defect in the position of the work center Cl relative to the articulation point O has as its main contributor the defect in the positioning of the center Cl relative to the template 34 and the variation in the tool dimension between the template 34 and the articulation point O of the universal joint 35.

[0242] Statistically and by experience, a work center Cl located in a sliding sphere centered on point O and with a radius equal to 5 times the location defect of the center Cl relative to the template 34 is sufficient to optimize the value of the moments brought into play during the sliding of the edge 1000 on the stop 32.

[0243] The steps of loading, obtaining the first equilibrium state and obtaining the second equilibrium state according to the method involving the assembly 1 and implementing the welding installation 3 make it possible to obtain the following advantageous results:

[0244] - In the loading step, the reversible locking means 330 blocks the translation of the carriage 33 and the reversible locking means 3511, 3521 block the rotations of the gimbal 35.

[0245] Thus, the welding template 34 is locked in position and the loading of the assembly 1 onto the welding template 34 automatically or manually is facilitated.

[0246] - In the step of obtaining the first equilibrium state, the pitch correctors 3510 and yaw 3520 are adjusted to orient, after unlocking the rotations of the gimbal 35, the working axis Al substantially perpendicular to the reference plane P3 and direct the axis Al substantially towards the center C3.

[0247] Thus, when the stop 32 is referenced, the overhanging portion 1100 interferes and then cooperates directly with the surface 320b of the stop clearance 320, the working axis A1 and the center C3 passing from a substantially aligned state to an aligned state, the group 36 occupying an intermediate equilibrium state not very different from the first equilibrium state. The friction which opposes obtaining the second equilibrium state is thus limited.

[0248] - In the step of obtaining the second equilibrium state, the carriage 33 moves according to a direction perpendicular to the plane P3 by exerting the force F and the surface 320b guides the free portion 1100 of the set 1, the conditions of the alignment of the axis Al with the center C3 being maintained. At time ti, additional moments CMnY, CMtY, CMnZ, CMtZ associated with the counter force CF are applied to the group 36, the moments CMnY and CMnZ opposing the resultants (CMtY,MY,GY) and (CMtZ,MZ).

[0249] The working center Cl substantially coincident with the articulation point O limits in value the moments CMtY and CMtZ by lever arm effect, and the moments CMnY and CMnZ exceed in value the resultants (CMtY,MY,GY) and (CMtZ,MZ) at time ti. The sliding of the edge 1000 to the surface 320a of the stop clearance 320 is made possible.

[0250] When the surface 320a receives a nitriding treatment, the coefficient of friction of the assembly 1 on the stop 32 is reduced and the values ​​of the moments CMtY and CMtZ are reduced accordingly. The sliding of the edge 1000 on the surface 320a of the stop set 320 is favored.

[0251] The first tubular component 10 being thickened by the sleeve 101 mounted on the inner surface of the cylindrical portion 100, the working plane PI and the reference plane P3 more easily find the conditions for alignment at time tf.

[0252] The surface 320b of the stop set 320 guiding the free portion 1100 of the assembly 1, the conditions for alignment of the working axis Al with the reference point C3 are maintained between ti and tf.

[0253] In a work engagement step, the first reversible locking means 330 blocks the translation of the carriage 33 and the reversible locking means 3511, 3521 block the rotations of the universal joint 35 and the stop 32 is retracted.

[0254] In this step of engaging the work, the following advantageous results:

[0255] - After blocking the translation, the force F exerted by the actuator 331 on the carriage 33 is only transmitted to the locking means 330 and is no longer transmitted to the stop 32.

[0256] Thus, the stop 32 is free of constraint along the X axis.

[0257] - Optionally again, the force F can be released by the actuator 331 in a manner automatic following confirmation of the locking actions by the organs 330, 3511, 3521.

[0258] - According to a preferred embodiment, the chassis 310 may comprise a double form and the movable part of the retraction mechanism of the stop 32 a double counter form, the double form and the double counter form being able to find the conditions of an embedding and an indexing.

[0259] Thus, after retraction of the stop 32, the work space delimited by the plane P3 is free of any member other than the frame 310 if the latter is configured as such. Such clearance promotes the approach and orientation of the welding head 30 relative to the welding edge 1000.

[0260] - The set 1 comprising the first and second components 10, 11 is obtained by crimping the second component 11 onto the first component 10 following a preliminary pre-assembly step using the crimping means 2.

[0261] Thus, the welding template 34 which comprises the receiving surfaces 3411 and 3412 capable of receiving the support surfaces 102a, 102b, 103a, 103b belonging to the first component 10 alone, can be configured to leave the work space delimited by the work plane P3 free. The welding head 30 can be approached and oriented relative to the welding edge 1000 without interference with the welding template 34.

[0262] Such easy access promotes welding conditions and quality.

[0263] In a welding step, the assembly 1 comprising the first and second components 10, 11 preassembled by crimping is welded along the edge 1000 by approaching the welding head 30 which uses MIG / MAG technology. A circular weld bead is deposited at the periphery, along the joint 14.

[0264] The welding head 30 which defines an axis A4 approaches the edge 1000 at an initial instant tsi of the welding, then after welding, moves away from the edge 1000 at a final instant tsf. Optionally, the weld bead comprises several adjacent beads having overlaps. During the welding operation, that is to say between tsi and tsf, the turning device / positioner 31 drives the assembly 1 and therefore the shoulder 13 in rotation about an axis A2. The positioner 31 and the frame 310 are configured so that the axis A2 contains the center C3 and is parallel to the plane P3 as exactly as possible.

[0265] With reference to [Fig.7], the MIG / MAG technology tolerates variations in the distance between the welding head 30 and the lap joint 14 when the head 30 remains directed towards the edge 1000. Such a distance (in English: “stick out”) which is typically set to reach the average value of 13 mm supports variations in the interval [8 mm; 18 mm],

[0266] Thus, the conformity of the weld bead is not altered if the distance is maintained within the interval [8mm - 18 mm]. Typically, the weld bead penetration criterion will be maintained in conformity despite these variations.

[0267] With reference to [Fig.7], the MIG / MAG technology does not tolerate offsets of the welding head 30 relative to the lap joint 14, whether the head is at the level of the single thickness or the double thickness.

[0268] Thus, the penetration amplitude of the weld bead may be unacceptable and weld defects (over-penetration, piercings) are all the more likely to occur if the overlap and non-overlap zones have dissimilar thicknesses.

[0269] According to a preferred embodiment, the welding head 30 is oriented at time tsi substantially perpendicular to the axis A2 of the turning gear, the angle a between the axis A4 of the head 30 and the axis A2 being in an interval [60°, 90°], preferably [80°, 90°].

[0270] The welding step involving the assembly 1 and implementing the welding installation 3 makes it possible to obtain the following advantageous results:

[0271] - The set 1 comprising the first and second components 10, 11 is obtained by crimping the second component 11 onto the first component 10 following a preliminary step using the crimping means 2. The lap joint 14 has a clearance of less than 0.2 mm as a consequence of the crimping.

[0272] Thus, the welding conditions of the first component 10 with the second component 11 are improved, a clearance at the right of the lap joint 14 being limited a parameter to be controlled to guarantee the conformity of the weld bead.

[0273] - At time tsi, the welding head 30 is oriented perpendicular to the axis of the turning gear A2. The head 30 is also directed towards the edge 1000 at an initial distance of 13 mm. In addition, the shoulder 13 is aligned with the planes PI, P3 perpendicular to the axis of the turning gear A2.

[0274] Thus, between tsi and tsf, that is to say during the rotation of the turning gear 31, the welding head 30 remains directed towards the welding edge 1000 substantially perpendicular to the axis of the turning gear A2 and the “stick out” between the head 30 and the edge 1000 remains within the interval [8mm - 18mm]. The position of the welding head 30 relative to the welding edge 1000 has little or no offset and the risks of the appearance of welding defects are eliminated.

[0275] During production and during rotation of the turning gear 31, the edge 1000 is the seat of a dispersion of radial beating relative to the axis A2 tolerated by the MIG / MAG technology.

[0276] - Between tsi and tsf, the work center Cl is substantially confused with the center of reference C3, the reference center C3 belonging to the axis A2. Thus the radial runout relative to the axis A2 of which the edge 1000 is the seat is minimized. The dispersion of radial runout during production is also minimized.

[0277] - The edge 1000 is the seat of an axial beat relative to the head 30 which is negligible. see zero therefore typically included in an interval [-0.5 mm, 0.5 mm]. The requirement of absence of appearance of welding defects such as over-penetration, under-penetration, or piercing, is satisfied.

[0278] A larger axial runout typically greater than + / - 1.5 mm would not have been tolerated by MIG / MAG technology.

[0279] - The first tubular component 10 comprises a surface-mounted sleeve 101 in inner side of the first cylindrical portion 100, said sleeve 101 having a plane boundary 101a aligned with the plane end 100a, the plane faces 100a and 101a delimiting the shoulder 13 and the welding edge 1000. Between tsi and tsf, that is to say during of the rotation of the turning gear 31, the welding head 30 is directed towards the welding edge 1000 substantially perpendicular to the axis of the turning gear. Such an orientation relative to the edge 1000 and to the joint 14 tends to increase the weld penetration.

[0280] Thus, the thickening provided by the sleeve 101 is advantageous given the welding condition created by the orientation of the torch 30. The repeatability of the welding operation and the conformity of the weld bead are ensured.

[0281] The means according to the invention allows a reference setting of a fitting of two components defining a working plane according to a reference plane defined by a retractable stop. The function of the means is to eliminate axial flutter associated with rotation around an axis perpendicular to the reference plane. Such a means can be advantageously used when the application method implements a tool / technology tolerating radial flutter, the tool being able to work radially or axially, preferably axially.

[0282] Brushing, polishing, painting or other processes tolerating radial movement but not tolerating axial movement will advantageously use the means according to the invention for working in rotation at a controlled distance in an axial direction.

[0283] The means according to the invention allows a reference setting of a fitting of two components defining a working plane and a working axis simultaneously according to a plane and a reference point defined by a retractable stop. The invention is applicable if the fitting has a working axis whose positioning is repeatable, the orientation and position of the working plane relative to the working axis being variable. The function of the means is to eliminate axial runout when the fitting is rotated about an axis perpendicular to the reference plane passing through the reference point. This means can be advantageously used when the application method implements a tool / technology tolerating radial runout, the tool being able to work radially or axially, preferably radially.

[0284] Welding, painting or other processes tolerating radial runout but not tolerating axial runout will advantageously use the means according to the invention for working in rotation at a controlled distance in a radial direction. List of reference signs

[0285] 1 Fitted assembly

[0286] 10 First tubular component

[0287] 100 First cylindrical portion

[0288] 100a Flat end

[0289] 101 Sleeve

[0290] 101a Plane boundary

[0291] 102 Hook

[0292] 102a, 102b Hook bearing surfaces

[0293] 103 Body

[0294] 103a, 103b Body support surfaces

[0295] 1000 Edge

[0296] 11 Second component

[0297] 110 Second cylindrical portion

[0298] 1100 Overhanging portion

[0299] 111 Tube

[0300] 112 Bride

[0301] 112a, 112b, 112c Flange bearing surfaces

[0302] 12 crimped fitted portion

[0303] 13 Shoulder

[0304] 14 Lap joint

[0305] 2 Crimping means

[0306] 21 Crimping template

[0307] 22 Set of jaws

[0308] 3 Machine

[0309] 30 welding head

[0310] 31 Positioner

[0311] 310 Chassis

[0312] 32 Retractable stop

[0313] 320 Set of stops

[0314] 320a Flat surfaces facing the outer edge 1000

[0315] 320b Passage section of the stop

[0316] 33 Chariot

[0317] 330 First reversible locking means

[0318] 331 Actuator

[0319] 332 Rail

[0320] 333 Shuttle

[0321] 34 Template

[0322] 341 Reception areas

[0323] 3411 Hook-related reception surfaces

[0324] 3412 Body-related reception surfaces

[0325] 36 Group consisting of set 1 and template 34

[0326] 35 Cardan

[0327] 351 First pivoting organ

[0328] 3510 Angular return element

[0329] 35100a,b Pair of springs

[0330] 35101 Came

[0331] 35102a,b Pair of adjustable rear stops

[0332] 3511 Reversible angular locking means

[0333] 3512 Shaft of the first pivoting member

[0334] 352 Second pivoting organ

[0335] 3520 Angular pre-positioning element

[0336] 35200a,b Spring pair

[0337] 35201 Came

[0338] 35202a,b Pair of adjustable rear stops

[0339] 3521 Reversible locking means

[0340] 3522 Shaft of the second pivoting member

[0341] PI Work plan

[0342] P3 Reference Plane

[0343] Al Axis of work

[0344] A10 First fitting axis

[0345] Garlic Second fitting axis

[0346] A2 Chassis rotation axis

[0347] A4 Welding torch axis

[0348] Cl Work Center

[0349] C3 Reference Center

[0350] F Effort

[0351] CF Counter effort

[0352] G Force applied to the center of gravity

[0353] X Direction of movement of the carriage

[0354] Y Axis of the first pivoting member

[0355] Z Axis of the second pivoting member

[0356] O Point of articulation O

[0357] RTY Angular stiffness of the pitch corrector

[0358] RLZ Angular stiffness of the yaw corrector

Claims

Claims

1. Automatic machine (3) for referencing an assembly fitted (1), the fitted assembly (1) comprising: a first component (10) having a first tubular cylindrical portion (100), the first tubular cylindrical portion (100) having a free external edge (1000) which is inscribed in a plane PI, a second component (11) having a second cylindrical portion (110), said second cylindrical portion (110) being fitted into the first tubular cylindrical portion (100), the automatic machine (3) comprising: an automatic positioner (31) comprising a chassis (310), an automatic stop (32) retractable relative to the chassis (310), said stop (32) being movable between a retracted position and a reference position, said stop defining, in the reference position, a reference plane P3 repeatable in position relative to the chassis (310), an automatic carriage (33) movable in translation relative to the chassis (310) between a retracted position and a working position, the translation direction of the carriage being perpendicular to the reference plane P3, an automatic template (34) configured to position and clamp the fitted assembly (1), an automatic universal joint (35) connecting the template (34) to the carriage (33), comprising a first pivoting member (351) around a substantially horizontal axis, and comprising a return element (3510) and a second pivoting member (352) comprising a pre-positioning element (3520), the return element (3510) and the pre-positioning element (3520) being capable of pre-orienting the plane PI in a manner substantially parallel to the plane P3 in the recoil position, the fitted assembly (1) positioned and clamped in the template (34) occupying a first state of equilibrium, the universal joint (35) being configured so that the fitted assembly (1) occupies a second state of equilibrium in which the planes P1 and P3 coincide when the carriage (33) is in the working position, the second state of equilibrium being obtained from the first state of equilibrium by automatic movement of the carriage (33) between the recoil position and the working position, by rotation of the pivoting members (351), (352) and by sliding and friction of the free external edge (1000) on the stop (32).

2. Automatic machine (3) according to claim 1, in which the carriage (33) comprises a reversible translation locking means (330) and an actuator (331), said reversible translation locking means (330) locking / unlocking the translation of the carriage (33) relative to the chassis (310), the actuator (331) moving the carriage (33) between the recoil position and the working position, in which the first pivoting member (351) comprises a reversible angular locking means (3511) and in which the second pivoting member (352) has an axis substantially perpendicular to the direction of translation of the carriage (33) a reversible angular locking means (3521), the reversible angular locking means (3511, 3521) in combination automatically locking / unlocking the rotation of the universal joint (35).

3. Automatic machine (3) according to claim 1 or 2, in which the template (34) is movable in rotation relative to the carriage (33) around an articulation point O of the universal joint (35) and in which the fitted assembly (1) positioned and clamped in the template (34) defines a fitting axis Al, the axis Al intersecting with the work plane PI at a work center Cl, the location of the points Cl being in a sliding sphere centered on the articulation point O of the universal joint (35) and of radius equal to five times the positioning error of the point Cl relative to the template (34).

4. Automatic machine (3) according to any one of the preceding claims, in which the stop (32) receives a surface treatment promoting the sliding of the free external edge (1000) relative to the stop (32).

5. Automatic machine (3) according to any one of the preceding claims, in which the stop (32) receives a surface treatment and / or at the heart promoting the wear resistance of the stop (32) by relative friction of the free external edge (1000) with the stop (32).

6. Automatic machine (3) according to any one of the preceding claims, in which the template (34) defines a theoretical working axis Alth perpendicular to the plane P3 in the first equilibrium state, the stop (32) defining in the reference position a reference point C3 relative to the chassis (310), the angular return (3510) and angular pre-positioning (3520) elements being adjustable and pre-aligning the axis Alth with the reference point C3 in the first equilibrium state.

7. Automatic machine (3) according to any one of the preceding claims, in which the fitted cylindrical portion (100) of the assembly (1) positioned and clamped in the template (34) defines a repeatable axis Al relative to the template (34) and aligned with the theoretical axis Alth, in which also the assembly (1) has a second cylindrical portion (110) projecting from the first fitted cylindrical portion (100), the projecting portion (1100) of the second cylindrical portion (110) being guided by the stop (32) in the reference position when the universal joint (35) is unlocked, the assembly (1) occupying the first state of equilibrium.

8. Automatic machine (3) according to any one of the preceding claims, in which the angular pre-positioning element (3520) is an angular return element.

9. Automatic method for referencing a fitted assembly (1) by means of an automatic machine (3), the fitted assembly (1) comprising: - a first tubular component (10) having a first cylindrical portion (100), said first tubular cylindrical portion (100) having a free external edge (1000) inscribed in a plane PI, - a second component (11) having a second cylindrical portion (110), said second cylindrical portion (110) being fitted into the first tubular cylindrical portion (100), the method implementing: - the automatic machine (3), comprising: • an automatic positioner (31) comprising a chassis (310), • an automatic stop (32) retractable relative to the chassis (310), movable between a retracted position and a reference position, said stop (32) defining, in the reference position, a reference plane P3 repeatable in position relative to the chassis (310), • an automatic carriage (33) movable in translation relative to the chassis (310) between a recoil position and a working position, the direction of translation of the carriage being perpendicular to the reference plane P3, • an automatic template (34) configured to position and clamp the fitted assembly (1), • an automatic universal joint (35) connecting the template (34) to the carriage (33), comprising a first pivoting member (351) around a substantially horizontal axis and comprising a return element (3510), and a second pivoting member (352) comprising a pre-positioning element (3520), the return element (3510) and the pre-positioning element (3520) being capable of pre-orienting the plane PI in a manner substantially parallel to the plane P3 in the recoil position, the fitted assembly (1) positioned and clamped in the template (34) occupying a first state of equilibrium, the universal joint (35) being configured so that the fitted assembly (1) occupies a second state of equilibrium in which the planes PI and P3 are merged, when the carriage (33) is in the working position, the automatic method comprising the following cyclic steps: - obtain the first state of equilibrium, - reference the stop (32), - obtain the second state of equilibrium, the second equilibrium state being obtained from the first state balance by automatic movement of the carriage (33) between the recoil position and the working position, by rotation of the pivoting members (351), (352) and by sliding and friction of the free external edge (1000) on the stop (32).

10. Method according to claim 9, in which the carriage (33) comprises a reversible translation locking means (330) and an actuator (331), said reversible translation locking means (330) locking / unlocking the translation of the carriage (33) relative to the chassis (310), the actuator (331) moving the carriage (33) between the recoil position and the working position, in which the first pivoting member (351) comprises a reversible angular locking means (3511) and in which the second pivoting member (352) has an axis substantially perpendicular to the direction of translation of the carriage (33), further comprises an angular pre-positioning element (3520) and a reversible angular locking means (3521), the reversible angular locking means (3511, 3521) in combination automatically locking / unlocking the rotation of the universal joint (35),the method comprising an automatic loading step prior to the step of obtaining the first state of equilibrium in which the carriage occupies the recoil position, the carriage is locked in translation by the means (330), the universal joint (35) is blocked in rotation by the means (3511, 3521) and the fitted assembly (1) is positioned and clamped on the template (34).,

11. Method according to claims 9 or 10, wherein the carriage (33) comprises a reversible translation locking means (330) and an actuator (331), said reversible translation locking means (330) locking / unlocking the translation of the carriage (33) relative to the chassis (310), the actuator (331) moving the carriage (33) between the recoil position and the working position, wherein the first pivoting member (351) comprises a reversible angular locking means (3511) and wherein the second pivoting member (352) has an axis substantially perpendicular to the direction of translation of the carriage (33), further comprises an angular pre-positioning element (3520) and a reversible angular locking means (3521), the reversible angular locking means (3511, 3521) in combination automatically locking / unlocking the rotation of the universal joint (35),the method comprising a step of engaging the work subsequent to the step of obtaining the second equilibrium state in, in which the carriage occupies the working position, the carriage is locked in translation by the means (330), the universal joint (35) is blocked in rotation by the means (3511, 3521), the fitted assembly (1) being positioned and clamped on the template (34).

12. Method according to any one of claims 9 to 11, in which a step of pre-assembling the first and second components 10 and 11 is carried out prior to the step of obtaining the first equilibrium state.

13. Method according to claim 12, in which the pre-assembly step is a crimping, in which the template (34) defines a theoretical axis Alth and in which the crimping is carried out by isostatic positioning of the component 10 according to external bearing surfaces SI, the fitted cylindrical portion (100) of the assembly (1) after crimping defining a repeatable axis Al relative to the bearing surface SI, the repeatable axis Al being aligned with the theoretical axis Alth when the assembly (1) is positioned and clamped on the template (34) according to the bearing surfaces SI.

14. Method according to any one of claims 9 to 13, in which the machine (3) is a welding installation (3) and in which a welding step is consecutive to the work engagement step.

15. Method according to claim 14, in which the welding installation (3) comprises a welding head (30) defining an axis A4, in which the stop (32) in the reference position defines a center C3 and in which the positioner (31) rotates the chassis (310) around an axis A2 perpendicular to the plane P3 and passing through the center C3, the welding step being carried out by aligning the axis A4 with the planes PI and P3 combined and rotating the chassis (310) around the axis A2.

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