Method of joining a side edge of a roof panel to an upper side stretcher of the body by brazing.

Abstract

The invention relates to a method of assembling by brazing a side edge of the roof (201) of a motor vehicle onto an upper side rail (111) of said vehicle, said method comprising a step of making, from the top of the roof of said vehicle, a brazing bead along a junction line between, on the one hand, an oblique section (201A) of said side edge of roof (201), oriented downwards and on the inner side, and on the other hand, an oblique face (111A) of said upper side rail (111), also oriented downwards and on the inner side; characterized in that, prior to and during said step of making the brazing bead, said method comprises a step of applying, from the underside of said roof and via clamping means (11), surface support forces against and along the inner face of said oblique section (201A). Figure to be published with the abbreviation: Fig. 3

Description

Title of the invention: Method of assembling by brazing a side edge of a roof on an upper side stretcher of the body Technical field

[0001] The present invention relates generally to the assembly dedicated to mounting a roof on top of a motor vehicle body comprising two body sides provided with upper stretchers connected by at least two front and rear cross members. Prior art

[0002] During the process of assembling a roof at the top of a body of a motor vehicle, the two lateral edges of this roof are assembled on the two upper stretchers forming the peaks of the two sides of the body of this vehicle.

[0003] Each lateral edge of the roof and the corresponding body side are in contact along substantially a junction line between, on the one hand, an oblique return of this lateral edge of the roof, oriented downwards and towards the internal side, and on the other hand, an oblique side of this upper stretcher, also oriented downwards and towards the internal side.

[0004] The assembly of each lateral edge of the roof on the corresponding upper stretcher is conventionally ensured via a brazing bead, produced along this junction line, by a brazing head carried by a robotic arm, which also makes it possible to ensure sealing between these two parts.

[0005] In order to guarantee optimum quality of the welding beads, the clearance between the oblique return of each lateral edge of the roof and the oblique side of the corresponding upper stretcher must be zero or almost zero (less than 0.3 millimeters) when the laser welding head of the robotic arm passes.

[0006] In order to ensure the plating between the lateral edges of the roof and the upper stretchers of the body sides, it is known to use a so-called "centipede" gantry enveloping the vehicle, this gantry comprising in its upper part two longitudinal beams each carrying several pressure pads distributed longitudinally above and along a corresponding lateral edge of this roof.

[0007] These pressure pads make it possible to apply, during the production of the weld-braze beads, surface support forces against and along the two lateral edges of this pavilion.

[0008] The design of such a gantry, however, proves to be particularly expensive.

[0009] Furthermore, and due to their proximity to the welding head when producing the weld beads, the pressure pads are subjected to very high thermal gradients, which leads to their rapid degradation and requires their regular replacement.

[0010] It is also known, in particular from document EP 2 473 312 B1, to provide, on each laser welding device, two rotary pressure rollers acted upon by jacks to press the roof sheet metal against that of the passenger compartment side along a line parallel to the junction line between these two sheets, so as to hold the lateral edge of the roof in position during the brazing operation.

[0011] The use of such pressure rollers, however, tends to generate a deformation of the roof sheet metal (ripple effect) at the end of the production of the braze weld bead when the welding head reaches the front or rear edge of the roof previously spot welded to a corresponding cross member of the vehicle body.

[0012] Such a ripple effect negatively impacts the aesthetic appearance of the upper face of the roof which is visible from the exterior of the vehicle.

[0013] Furthermore, and due to their proximity to the welding head when producing the weld beads, these pressure rollers also undergo very high thermal gradients leading to their rapid degradation and requiring their regular replacement. Presentation of the invention

[0014] The present invention therefore aims to improve the situation.

[0015] To this end, it proposes a method of assembling by brazing a lateral edge of a motor vehicle roof on an upper side stretcher of the body of said vehicle, said method comprising a step consisting of producing, from above the roof of said vehicle, a brazing bead along a junction line between, on the one hand, an oblique return of said lateral edge of the roof, oriented downwards and on the internal side, and on the other hand, an oblique side of said upper side stretcher of the body, also oriented downwards and on the internal side; characterized in that, prior to and during said step of producing the brazing bead, said method comprises a step of applying, from below said roof and via plating means, surface bearing forces against and along the internal face of said oblique return.

[0016] By ensuring such plating along the junction line between the oblique return of the lateral edge of the roof and the oblique side of the upper stretcher, the method according to the invention makes it possible to guarantee optimal quality of the weld bead and without any undulating effect of the roof sheet.

[0017] The bearing force being exerted against a portion of the lateral edge of the roof intended to be concealed by the interior roof trim, the method according to the invention makes it possible to avoid any negative impact on the perceived quality of this vehicle.

[0018] Furthermore, and due to the fact that the application of this support force is carried out from below the pavilion in an area relatively far from the welding head, the method according to the invention makes it possible to limit the intensity of the thermal gradients undergone. by plating means so as to improve their durability over time.

[0019] According to preferred characteristics of said method according to the invention: - said plating means comprise a pressing device carried by a robotic arm and comprising a frame supporting pressing elements; - each said pressing element is carried by a corresponding support member mounted to slide transversely relative to said frame; - each said support member is movable, between a retracted rest position and a deployed pressing position in which the pressing element carried by this support member is capable of applying a surface bearing force against an area of ​​the internal face of said oblique return; - each said support organ is controlled by a pneumatic or hydraulic actuator - said pressing device is introduced into the passenger compartment area of ​​said vehicle below said roof via an inlet opening located in the rear part of the body of said vehicle; - said plating means comprise several manual clamping members arranged by an operator along said junction line; - each said manual clamping member comprises two jaws urged towards each other by elastic return means and designed to come into contact respectively against the internal face of said oblique return and against a lower face of an element on the body side; - the intensity of the surface support force, exerted by one of the jaws of each said clamping member against the internal face of said oblique return, is adjustable by worm screw adjustment means; and / or - said brazing bead is produced by a brazing head carried by a robotic arm and powered by a laser source. Brief description of the drawings

[0020] The description of the invention will now be continued by the detailed description of several exemplary embodiments, given below for illustrative but non-limiting purposes, with reference to the appended drawings, in which: - [Fig.l] represents a schematic illustration of an assembly line for the roof at the top of the body of a motor vehicle, implementing the method according to the invention; - [Fig.2] is a perspective view of a motor vehicle body preparing to receive its roof; - [Fig.3] represents a cross-sectional view of a lateral edge of the pavilion held pressed by a pressing device carried by a robotic arm against a upper stretcher on the corresponding body side before the final assembly of these two elements by creating a weld-braze bead along their junction line; and - [Fig.4] represents a perspective cross-sectional view of a side edge of the roof held pressed by manual clamping members against an upper stretcher on the corresponding body side before the final assembly of these two elements by creating a weld-braze bead along their junction line. Description of the embodiments

[0021] [Fig.l] represents an assembly line 1 of a roof 200 at the top of a body 100 of a motor vehicle, including welding operations.

[0022] We define with respect to this vehicle a direct orthogonal reference frame XYZ comprising three axes perpendicular two by two, namely: - a longitudinal axis X, parallel to the ground and coincident with the general direction of movement of the vehicle on this assembly line 1; - a transverse axis Y, also parallel to the ground and perpendicular to the X axis; and - a vertical axis Z, perpendicular to the ground as well as to the horizontal XY plane.

[0023] In the remainder of the description and with reference to the reference defined above, the terms “longitudinal” or “longitudinally” will refer to a direction parallel to the X axis, the terms “transverse” or “transversely” will refer to a direction parallel to the Y axis, and the terms “vertical” or “vertically” will refer to a direction parallel to the Z axis.

[0024] On the other hand and by convention, the terms "lower", "upper", "front" and "rear" will be understood in relation to the general orientation of the vehicle. The terms "lower" and "low" will indicate a greater proximity to the ground in the vertical direction than the terms "upper" or "high". The term "front" will indicate a positioning oriented towards the front of the vehicle in the horizontal direction and the term "rear" will indicate a positioning oriented towards the rear of this vehicle in the same horizontal direction.

[0025] Furthermore, the terms “external” and “internal” will be used to define the relative position of an element with reference to the median vertical longitudinal plane of the vehicle. The element closest to this plane will thus be described as internal as opposed to the other element further from this same plane which will be described as external.

[0026] Finally, the use of the term “substantially” will indicate that a slight deviation of 10 to 15° is allowed with respect to a predetermined nominal orientation, while remaining included within the scope of the invention. For example, “substantially vertical” will indicate that a deviation of the order of 10° to 15° relative to a strictly vertical orientation is permitted within the scope of the invention.

[0027] With reference to [Fig. 2], the body 100 comprises, in a conventional manner, two body sides 110 whose respective tops are constituted by two upper stretchers 111 provided to receive the two lateral edges 201 of the roof 200.

[0028] Still with reference to this [Fig.2], the body 100 also comprises front 112 and rear 113 upper cross members extending transversely between the two upper stretchers 111 and on which the front 202 and rear 203 edges of the roof 200 rest transversely.

[0029] This body 100 may also comprise one or more intermediate upper crosspieces 114, 115 extending transversely between the two upper stretchers 111 and on which the corresponding portions of the roof 200 rest transversely.

[0030] As illustrated by [Fig. 3], each lateral edge 201 of the roof 200 is folded at an obtuse angle so as to form an oblique return 201A oriented downwards and on the internal side. Each upper stretcher 111 of the body side 110 has an oblique section 11 IA extending downwards from the internal side and extending on the internal side by a substantially horizontal plate 11 IB resting fixedly on a reinforcement 116 on this side of the body 110.

[0031] Referring again to [Fig.l], the assembly line 1 comprises a rail transport track 2 ensuring the longitudinal movement of a vehicle body 100 on which a roof 200 is to be mounted between a first station PI and a second station P2.

[0032] This assembly line 1 comprises, at the level of the first station PI and in a laterally eccentric zone on the left lateral side of the transport track 2, a container 3 of pavilions 200 arranged near a positioning table 4 extending along an inclined plane. A robotic loading arm 5 is further arranged between the container 3 and this positioning table 4.

[0033] Also at the level of the first station PI but in an area laterally closer to the left lateral side of the transport track 2, the assembly line 1 comprises a supporting frame 6 provided with means for gripping a roof 200 and which can be handled by a robotic handling arm 7.

[0034] Still at this first station PI, in a zone laterally close to the right lateral side of the transport track 2, the assembly line 1 comprises at least one robotic arm 8 equipped with a spot welding head intended to carry out the fixing of the front 202 and rear 203 edges of the roof 200 respectively on the front crossmember 112 and the rear crossmember 113 of the body 100.

[0035] The assembly line 1 also includes, at the second station P2, a safety cabin 10 crossed by transport track 2.

[0036] Inside this safety cabin 10 in an area located longitudinally near its entrance and laterally near the left side of the transport track 2, the assembly line 1 comprises a pressing device 11 carried by a robotic handling arm 12.

[0037] As illustrated by [Fig. 3], this pressing device 11 comprises a frame 1 IA supporting pressing pads 1 IB each carried by a corresponding support member 1 IC mounted to slide transversely relative to the frame 11 A.

[0038] Controlled for example by a pneumatic or hydraulic actuator, each support member 1 IC is movable, between a retracted rest position and a deployed pressing position in which the pressure pad 1 IB carried by this support member 1 IC is capable of applying a surface bearing force against a zone of the internal face of the oblique return 201A of the corresponding lateral edge of the roof 201.

[0039] The safety cabin 10 also houses, in an area longitudinally further from its entrance, two robotic arms 13 arranged laterally on either side of the transport track 2.

[0040] Each of these robotic arms 13 carries a welding head powered by a laser source 14 and intended to achieve the watertight fixing of a respective lateral edge 201 of the roof 200 to the corresponding upper stretcher 111 of the body 100.

[0041] We will now briefly describe the operation of the assembly line 1 of a 200 roof on a 100 body.

[0042] During a first step, the robotic loading arm 5 retrieves a pavilion 200 from the container 3 and transfers it to the positioning table 4.

[0043] The pavilion 200 will then slide by gravity on rollers arranged on this inclined table 4 so as to automatically settle into a predetermined reference position.

[0044] The robotic handling arm 7 will then bring the carrier chassis 6 above this positioning table 4 so that it can load the roof 200, then place this chassis 6 carrying this roof 200 on top of the body 100 parked on the first PL station.

[0045] While this supporting frame 6 holds the roof 200 in the appropriate position, the robotic arm 8 will thus be able to spot weld the front 202 and rear 203 edges of this roof 200 respectively to the front cross member 112 and to the rear cross member 113 of the body 100.

[0046] The supporting frame 6 will then be detached from the roof 200 so that the handling arm 7 can return it to its initial position. The body 100 will then advance along the transport line 2 to the second station P2 located inside the safety cabin 10.

[0047] The robotic handling arm 12 will then introduce, via an entry opening located in the rear part of the body 100 (and corresponding for example to the future area of ​​installation of the window or the rear flap of the vehicle), the pressing device 11 into the passenger compartment area of ​​the vehicle below the roof 200.

[0048] The support members 1 IC carrying the pressure pads 1 IB are then brought into their deployed pressing position so that these pressure pads 1 IB apply surface bearing forces against and along the internal faces of the oblique returns 201A of the two lateral edges of the roof 201 (see [Fig.3]).

[0049] Alternatively, the pressing device 11 and the handling arm 12 may be arranged differently so that the introduction of this pressing device 11 into the passenger compartment area is carried out via an entry opening located in the front or lateral part of the body, corresponding for example to the future installation area of ​​the windshield or a door.

[0050] Due to the downwardly oriented profile and the internal side of the oblique returns 201A, the surface support forces exerted by the pressure pads 11B make it possible to vertically constrain these oblique returns 201A against the oblique sides 11 1A of the upper stretchers 111 so as to avoid any play between these elements (or at least to ensure that this play is systematically less than 0.3 millimeters) over the entire length of the lateral edges 201 of the roof 200.

[0051] While this pressing device 11 forces the oblique returns 201A against the oblique sides 111A of the upper stretchers 111, the robotic arms 13 will thus be able to produce the welded-brazing beads ensuring the final and watertight assembly of the lateral edges 201 of the roof 200 on these upper stretchers 111 of the body sides 110.

[0052] According to an alternative embodiment illustrated by [Fig. 4], the assembly line 1 is devoid of a pressing device such as 11 controlled by a robotic arm. The pressing of the oblique returns 201A of the lateral edges of the roof 201 against the oblique sides 111A of the upper stretchers 111 is ensured by manual clamping members 15 arranged by an operator along each junction line between a lateral edge of the roof 201 and an upper stretcher of the body side 111.

[0053] These manual clamping members may comprise, for example, two jaws 15A, 15B urged towards each other by elastic return means not shown and provided to come to bear respectively against the internal face of the oblique return 201A of a lateral edge of the roof 201 and against a lower face of an element of the corresponding body side 110, such as the reinforcement 116 or a lining 117.

[0054] Endless screw adjustment means 15C advantageously make it possible to adjust the intensity of the surface support force exerted by one 15A of these jaws 15A, 15B against the internal face of the oblique return 201A of the lateral edge of the roof 201.

[0055] Many other variant embodiments are of course conceivable and it is recalled in this respect that the present invention is not limited to the embodiments described and shown, but also encompasses all variant embodiments within the reach of those skilled in the art.

Claims

Claims

1. Method of assembling by brazing a lateral edge of a roof (201) of a motor vehicle on an upper side stretcher of the body (111) of said vehicle, said method comprising a step consisting of producing, from above the roof (200) of said vehicle, a bead of brazing along a junction line between, on the one hand, an oblique return (201 A) of said lateral edge of the roof (201), oriented downwards and on the internal side, and on the other hand, an oblique face (11 IA) of said upper side stretcher of the body (111), also oriented downwards and on the internal side; characterized in that, prior to and during said step of producing the brazing bead, said method comprises a step of applying, from below said pavilion (200) and via plating means (11), surface bearing forces against and along the internal face of said oblique return (201 A).

2. A method of assembly by brazing according to claim 1, characterized in that said plating means comprise a pressing device (11) carried by a robotic arm (12) and comprising a frame (11A) supporting pressing elements (11B).

3. Method of assembly by brazing according to claim 2, characterized in that each said pressing element (1 IB) is carried by a corresponding support member (11C) mounted to slide transversely relative to said frame (1 IA).

4. Method of assembly by brazing according to claim 3, characterized in that each said support member (1 IC) is movable, between a retracted rest position and a deployed pressing position in which the pressing element (1 IB) carried by this support member (1 IC) is capable of applying a surface bearing force against a zone of the internal face of said oblique return (201A).

5. Method of assembly by brazing according to one of claims 3 or 4, characterized in that each said support member (1 IC) is controlled by a pneumatic or hydraulic actuator.

6. Welding assembly method according to one of claims 2 to 5, characterized in that said pressing device (11) is introduced into the passenger compartment area of ​​said vehicle below said roof (200) via an inlet opening located in the rear part of the body (100) of said vehicle.

7. A method of assembly by brazing according to claim 1, characterized in that said plating means comprise several manual clamping members (15) arranged by an operator along said junction line.

8. A method of assembly by brazing according to claim 7, characterized in that each said manual clamping member (15) comprises two jaws (15A, 15B) urged towards each other by elastic return means and provided to come respectively into abutment against the internal face of said oblique return (201 A) and against a lower face of an element (116, 117) on the body side (110).

9. A method of assembly by brazing according to claim 8, characterized in that the intensity of the surface bearing force, exerted by one (15A) of the jaws (15A, 15B) of each said clamping member (15) against the internal face of said oblique return (201A), is adjustable by worm screw adjustment means (15C).

10. Method of assembly by brazing according to one of claims 1 to 9, characterized in that said brazing bead is produced by a brazing head carried by a robotic arm (13) and supplied by a laser source (14).

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