SE541042C2

SE541042C2 - A welding arrangement and a vehicle comprising such a welding arrangement

Info

Publication number: SE541042C2
Application number: SE1651495A
Authority: SE
Inventors: Emil Pettersson; Patrik Thuresson
Original assignee: Scania Cv Ab
Priority date: 2016-11-16
Filing date: 2016-11-16
Publication date: 2019-03-19
Also published as: DE102017010291B4; SE1651495A1; DE102017010291A1

Abstract

The invention relates to a welding arrangement (10), comprising a first item (20) and a second item (30) adapted to be welded together, each item (20; 30) comprising a main portion (20’; 30’) with a first surface (21; 31) and a second opposed surface (22; 32), wherein the first item (20) comprises a protrusion (24) extending from the main portion (20’). The protrusion (24) comprises at least one opening (26) and the second item (30) comprises at least one weld portion (34) projecting from the second surface (32), wherein the protrusion (24) is adapted to be folded over the at least one weld portion (34), such that the at least one weld portion (34) extends through the opening (26) in the protrusion (24), and wherein the at least one weld portion (34) is adapted to be melted.The invention also relates to a vehicle (1) comprising such a welding arrangement (10).

Description

A welding arrangement and a vehicle comprising such a welding arrangement TECHNICAL FIELD The present invention relates to a welding arrangement and a vehicle comprising such a welding arrangement. The invention more specifically relates to a welding arrangement involving plastic items attached to each other by welding.

BACKGROUND When welding plastic parts together a turret on one part is typically fitted into a hole of the other part. The turret is then melted over the hole and a rivet head is formed. The rivet head ensures that the two parts are fixedly attached to each other. The turret may be positioned on the backside of a visual surface, such as a styling surface or similar, adapted to be seen for example from inside or outside a vehicle. This may cause problems with visual defects, such as sink marks. The longer the turret needs to be in order to achieve a strong joint, the thicker turret base is needed and the greater is the risk for sink marks. The size of the turret thus affects the risk for sink marks and various solutions for avoiding such sink marks exist. Document US2013112336 A1 discloses a method for assembling at least two plastic components to each other. The method comprises providing a first part with a first protruding relief; providing a second part with a first orifice; inserting the first protruding relief through the first orifice; and creating a connection of the first part to the second part by melting the first protruding relief. The second part comprises a second protruding relief located near the first orifice such that the second protruding relief melts when the first protruding relief is melted. This way, the height of the first protruding relief may be reduced whereby the risk of a shrink pocket in the first part is reduced. Document JP2010208173 A discloses a heat crimping structure for a thermoplastic resin. The structure comprising a first part with a protrusion adapted to be melted to form a rivet head, and a second part comprising an annular protrusion. The annular protrusion is adapted to restrict the spreading of the rivet head, whereby less material is needed in the protrusion of the first part. This way, the risk for visual defects is reduced.

SUMMARY OF THE INVENTION Despite known solutions in the field, there is still a need to develop a welding arrangement, which overcomes or alleviates at least some of the drawbacks of the prior art.

An object of the present invention is therefore to achieve an advantageous welding arrangement, which reduces the risk of sink marks in a visual surface when welding two parts together.

This object is achieved by a welding arrangement and a vehicle comprising such a welding arrangement according to the independent claims.

Hence, according to an aspect of the present invention a welding arrangement comprising a first item and a second item adapted to be welded together is provided. Each item comprises a main portion with a first surface and a second opposed surface, wherein the items are adapted to be arranged with the second surface of the first item abutting the first surface of the second item, and wherein the first item comprises a protrusion extending from the main portion. The protrusion of the first item comprises at least one opening and the second item comprises at least one weld portion projecting from the second surface, wherein the protrusion of the first item is adapted to be folded over the at least one weld portion of the second item, such that the at least one weld portion extends through the opening in the protrusion of the first item, and wherein the at least one weld portion of the second item is adapted to be melted.

The first surface of the first item is suitably a visual surface. A visual surface is herein defined as a surface adapted to be seen from, for example, inside or outside a vehicle. A visual surface may be a styling surface, for example of an outer part of a vehicle, a surface on an inner panel of a vehicle or similar.

When welding together two items where one item has a visual surface, the item with the visual surface typically comprises a protrusion on the backside of the visual surface. The protrusion is adapted to be melted to form a rivet head and thus form a rivet joint holding the two items fixedly together. Depending on the size of the protrusion, draft angles during the production process may require a relatively thick base of the protrusion. The base is the part of the protrusion closest to the portion from which it extends. With a thick base the risk for sink marks on the visual surface is significant. By having a weld portion adapted to be melted on the second item, which does not have a visual surface, the risk for sink marks is no longer a problem. Since the weld portion forming the rivet head is not part of the first item, the weld portion can be configured in any way to ensure a strong rivet joint when it is melted. Hence, the risk for sink marks does not have to be taken into consideration since the first surface of the second item is not a visual surface. By configuring the first item with a protrusion adapted to be folded over the weld portion of the second item it is ensured that, when the weld portion is melted, a rivet head is formed over the folded protrusion. This way, the first item and the second item are fixedly attached to each other. Since the protrusion of the first item does not affect the strength of the rivet joint the protrusion can be configured in any way. The protrusion is thus suitably configured, such that sink marks are avoided on the visual surface. That is, the protrusion on the first item is suitably configured with a relatively thin base. The protrusion suitably has a thinner base than the weld portion on the second item.

The main portion of the first item may be an essentially flat portion and the first surface and the second surface of the first item may be essentially flat surfaces. The first surface and the second surface of the first item may extend essentially in parallel with each other. The protrusion may extend (project) from the second surface of the first item, essentially perpendicularly to the plane of the main portion of the first item. The protrusion may be a rib or web. The protrusion is suitably tapering in the direction away from the second surface of the first item. The protrusion thus suitably comprises a base and a tip, wherein the base is thicker than the tip. The height of the protrusion may be defined as the distance from the base to the tip of the protrusion. The height may thus define how far from the second surface of the first item the protrusion extends. The width of the protrusion is defined as the extension along the second surface of the first item. The width of the protrusion is thus the extension along a direction parallel with the second surface of the first item.

The main portion of the second item may be an essentially flat portion, and the first surface and the second surface of the second item may be essentially flat surfaces. The first surface and the second surface of the second item may extend essentially in parallel with each other. The weld portion may project from the second surface of the second item, essentially perpendicularly to the plane of the main portion of the second item. The weld portion may be a turret, a solid cylinder, a rib or web of any shape, or similar. The weld portion is suitably tapering in the direction away from the second surface of the second item. In the case where the weld portion is a turret the turret walls are suitably tapered such that the base of the wall is thicker than the tip of the wall. The height of the weld portion may be defined as the distance from the base to the tip of the weld portion. The height may thus define the how far from the second surface of the second item the weld portion projects. The width of the weld portion is defined as the extension along the second surface of the second item.

The main portion of the first item and the main portion of the second item may have corresponding shapes, such that the second surface of the first item follows the first surface of the second item.

The at least one opening in the protrusion of the first item may be a through hole. The at least one opening in the protrusion of the first item may alternatively be a recess in the protrusion, such as a slit or slot. The shape of the at least one opening suitably corresponds to the shape of the weld portion of the second item. Also, the dimensions of the at least one opening suitably correspond to the dimensions of the weld portion. This way, it is ensured that the weld portion will fit in the at least one opening. The at least one opening in the protrusion is thus suitably configured such that the base of the weld portion fits in the at least one opening. The at least one opening is suitably arranged on the protrusion, such that when the protrusion is folded over the weld portion the at least one opening is aligned with the weld portion.

The protrusion of the first item may be adapted to be folded in direction towards the second surface of the second item. The protrusion may be adapted to be folded, such that the folded portion of the protrusion abuts the second surface of the second item.

According to an embodiment of the invention the main portion of the second item comprises a through hole, through which the protrusion of the first item is adapted to extend. That is, the first item is suitably adapted to be positioned with the second surface of the first item abutting the first surface of the second item and with the protrusion extending through the hole of the second item. This way, the protrusion can be folded over the weld portion of the second item, such that the at least one opening in the protrusion surrounds the weld portion circumferentially. The through hole in the second item suitably has a shape corresponding to the shape of the protrusion. Thus, in the case where the protrusion is a rib the through hole in the second item may be an elongated slit. The through hole in the second item is suitably arranged such that the distance between the through hole and the weld portion essentially corresponds to the distance between the folding point of the protrusion and the at least one opening in the protrusion.

According to an embodiment of the invention the first item is adapted to be arranged, such that the protrusion is folded around an end edge of the main portion of the second item. This way, no through hole in the second item is needed. Also, by folding the protrusion around an end edge of the second item a soft end edge may be achieved. In this case, the protrusion of the first item may be arranged at an end of the main portion of the first item.

The first item may comprise metal, a composite material, plastics or any other material. The second item suitably comprises plastics. In the case where the first item is made of plastics the protrusion is suitably an integrated part of the main portion of the first item. In the case where the first item is made of metal the protrusion may be riveted to the main portion of the first item. The protrusion and the main portion of the first item are suitably of the same material. The weld portion of the second item is suitably an integrated part of the main portion of the second item. By configuring the second item with the weld portion adapted to be melted, the first item with the visual surface can comprise any material and still be welded together with the second item.

According to an embodiment of the invention the protrusion of the first item comprises a hinge portion. This way, the protrusion can easily be folded in direction towards the second surface of the second item without the occurrence of cracks in the protrusion. The hinge portion may be a recess or notch in the protrusion. The hinge portion suitably extends along the width of the protrusion. The hinge portion may be formed on the side of the protrusion facing the weld portion of the second surface or it may be formed on the side facing away from the weld portion of the second item. Alternatively, the protrusion comprises a hinge portion, which comprises recesses on both sides of the protrusion. The protrusion may comprise a hinge portion when the first item comprises a material that may crack when folding the protrusion. The protrusion suitably comprises a hinge portion when the first item comprises plastics. When the first item comprises metal and the protrusion thereby also comprises metal, the protrusion may be folded without a hinge portion. Thus, a hinge portion may not be needed when the protrusion is made of metal.

The hinge portion being a recess or notch in the protrusion facilitates separation of the first item and the second item when they have been welded together. That is, even though the weld portion has been melted and the first item is welded to the second item, the protrusion can be taken apart by breaking the hinge portion and the main portion of the first item and the second item can thereby be separated from each other. Only the folded portion of the protrusion of the first item will remain on the second item. The hinge portion thus facilitates recycling of the items. This is specifically advantageous when the first item and the second item are made of different materials.

According to an embodiment of the invention the protrusion of the first item comprises a plurality of openings and the second item comprises a plurality of weld portions. The protrusion may comprise a plurality of openings arranged in a row in direction of the width of the protrusion. The protrusion may alternatively or additionally comprise a plurality of openings arranged in a row in direction of the height of the protrusion. The second item may comprise a plurality of weld portions arranged in a row along a direction corresponding to the direction of the openings in the protrusion of the first item. The second item may thus comprise a plurality of weld portions arranged in a row along a direction parallel with the width of the protrusion. The second item may alternatively or additionally comprise a plurality of weld portions arranged in a row along a direction perpendicular to the height and the width of the protrusion. The position of the weld portions on the second item is suitably such that the openings in the protrusion are aligned with the weld portions when the protrusion is in a folded position.

According to an embodiment of the invention the protrusion of the first item has a base with a thickness which is less than 50 percent of the thickness of the main portion of the first item. The base of the protrusion is thus suitably at least 50 percent thinner than the thickness of the main portion of the first item. The thickness of the main portion of the first item may be defined as the distance between the first and the second surface. When the thickness of the base of the protrusion is less than 50 percent of the thickness of the main portion, the risk for sink marks is avoided. The thickness of the base of the protrusion is suitably less than 40 percent of the thickness of the main portion of the first item.

Further objects, advantages and novel features of the present invention will become apparent to one skilled in the art from the following details, and also by putting the invention into practice. Whereas embodiments of the invention are described below, it should be noted that it is not restricted to the specific details described. Specialists having access to the teachings herein will recognise further applications, modifications and incorporations within other fields, which are within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS For fuller understanding of the present invention and further objects and advantages of it, the detailed description set out below should be read together with the accompanying drawings, in which the same reference notations denote similar items in the various drawings, and in which: Figure 1 schematically illustrates a vehicle according to an embodiment of the invention; Figure 2a-c schematically illustrates a welding arrangement according to an embodiment of the invention; Figure 3 schematically illustrates a welding arrangement according to an embodiment of the invention; Figure 4a-b schematically illustrate a welding arrangement according to an embodiment of the invention; and Figure 5 schematically illustrates a welding arrangement according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS Figure 1 schematically shows a side view of a vehicle 1 comprising a propulsion unit 2. The vehicle 1 may further comprise at least one welding arrangement 10 comprising a first item and a second item welded together. The first item suitably comprises a first surface which is a visual surface on the vehicle 1. The first surface of the first item may constitute a surface of the exterior of the vehicle 1 or it may constitute a surface of the interior of the vehicle 1. The vehicle 1 may be a heavy vehicle, e.g. a truck or a bus. The vehicle 1 may alternatively be a passenger car. The vehicle may be manually operated, remotely operated or autonomously operated.

Figures 2a-2c schematically illustrate a welding arrangement 10 according to an embodiment of the invention. The welding arrangement 10 comprises a first item 20 and a second item 30 adapted to be welded together, each item comprising a main portion 20’, 30’ with a first surface 21, 31 and a second opposed surface 22, 32. The first surface 21, 31 and the second surface 22, 32 may extend essentially in parallel with each other. The items 20, 30 are adapted to be arranged with the second surface 22 of the first item 20 abutting the first surface 31 of the second item 30. The first item 20 comprises a protrusion 24 extending from the main portion 20’. The protrusion 24 comprises at least one opening 26 and the second item 30 comprises at least one weld portion 34 projecting from the second surface 32 of the main portion 30’, wherein the protrusion 24 of the first item is adapted to be folded over the at least one weld portion 34 of the second item 30, such that the at least one weld portion 34 extends through the opening 26 in the protrusion 24 of the first item 20, and wherein the at least one weld portion 34 of the second item 30 is adapted to be melted. With such a welding arrangement 10 a rigid attachment between the first item 20 and the second item 30 can be achieved without the risk of sink marks on the first surface 21 of the first item 20.

The first surface 21 of the first item 20 may be a visual surface adapted to be seen from, for example, inside or outside a vehicle 1 as disclosed in Figure 1.

The protrusion 24 of the first item 20 may extend from the second surface 22 of the first item 20, essentially perpendicularly to the plane of the main portion 20’ of the first item 20. The protrusion 24 may be a rib or web. The protrusion 24 may be tapering in the direction away from the second surface 22 of the first item 20. The protrusion 24 thus suitably comprises a base B and a tip T, wherein the base B is thicker than the tip T. This is illustrated in Figure 2a. The protrusion 24 may have a base B with a thickness which is less than 50 percent of the thickness of the main portion 20’ of the first item 20. When the thickness of the base B of the protrusion 24 is less than 50 percent of the thickness of the main portion 20’ of the first item 20, the risk for sink marks in the first surface 21 of the first item 20 is avoided.

The weld portion 34 may project from the second surface 32 of the second item 30, essentially perpendicularly to the plane of the main portion 30’ of the second item 30. The weld portion 34 is in this embodiment a turret but may be configured in other ways. The turret walls are suitably tapered such that the base of the wall is thicker than the tip of the wall.

The at least one opening 26 in the protrusion 24 of the first item 20 may be a through hole. The at least one opening 26 in the protrusion 24 of the first item 20 may alternatively be a recess in the protrusion 24, such as a slit or slot. The shape of the at least one opening 26 suitably corresponds to the shape of the weld portion 34 of the second item 30. The at least one opening 26 of the protrusion 24 may be arranged adjacent the tip T of the protrusion 24.

The protrusion 24 of the first item 20 may be adapted to be folded in direction towards the second surface 32 of the second item 30 as illustrated by an arrow in Figure 2a.

In this embodiment the main portion 30’ of the second item 30 comprises a through hole 36, through which the protrusion 24 of the first item 20 is adapted to extend. As shown in figure 2a the first item 20 is positioned with the second surface 22 of the first item 20 abutting the first surface 31 of the second item 30 and with the protrusion 24 extending through the hole 36 of the second item 30. The through hole 36 in the second item 30 suitably has a shape corresponding to the shape of the protrusion 24.

The protrusion 24 of the first item 20 may comprise a hinge portion 28. This way, the protrusion 24 can easily be folded in direction towards the second surface 32 of the second item 30 without the occurrence of cracks in the protrusion 24. The hinge portion 28 may be a recess or notch in the protrusion 24.

Figure 2b shows the welding arrangement 10 when the protrusion 24 of the first item 20 is in a folded position. In the folded position, the folded portion of the protrusion 24 extends essentially in parallel with the second surface 32 of the second item 30. The protrusion 24 has thus been folded over the weld portion 34, such that the weld portion 34 extends through the opening 26 in the protrusion 24 and the protrusion 24 thereby surrounds the weld portion 34 circumferentially. The through hole 36 of the second item 30 may be arranged such that the distance between the through hole 36 and the weld portion 34 essentially corresponds to the distance between the hinge portion 28 of the protrusion 24 and the opening 26 in the protrusion 24.

In Figure 2c the weld portion 34 of the second item 30 has been melted and a rivet head 38 has been formed of the melted weld portion 34. The folded protrusion 24 of the first item 20 is thus clamped between the rivet head 38 and the main portion 30’ of the second item 30. This way, the first item 20 and the second item 30 are welded together. Since the weld portion 34 to be melted is on the second item 30, the first item 20 may comprise any material while the second item suitably comprises plastics.

Figure 3 schematically illustrates a welding arrangement 10 according to an embodiment of the invention. The welding arrangement 10 may be configured as the welding arrangement 10 as disclosed in Figures 2a-2c with the difference that in this embodiment the first item 20 is adapted to be arranged, such that the protrusion 24 can be folded around an end edge 39 of the main portion 30’ of the second item 30. This way, no through hole 36 in the second item 30 is needed.

Figures 4a-4b schematically illustrate a welding arrangement 10 according to an embodiment of the invention. The welding arrangement 10 may be configured as the welding arrangement 10 as disclosed in Figures 2a-2c and Figure 3 with the difference that in this embodiment the protrusion 24 of the first item 20 comprises a plurality of openings 26 and the second item 30 comprises a plurality of weld portions 34. Also, the first item 20 may be adapted to be arranged, such that the protrusion 24 can be folded around an end edge 39 of the main portion 30’ of the second item 30 instead of through a through hole in the second item 30. Figure 4a shows the protrusion 24 of the first item 20 in an unfolded position. The openings 26 are arranged in a row in direction of the width of the protrusion 24 and the weld portions 34 of the second item 30 are arranged in a row along a direction parallel with the direction of the row of openings 26 in the protrusion 24. The position of the weld portions 34 on the second item 30 is suitably such that the openings 26 in the protrusion 24 are aligned with the weld portions 34 when the protrusion 24 is folded towards the second surface 32 of the second item 30. Figure 4b shows the protrusion 24 in a folded position where each weld portion 34 is surrounded circumferentially by the protrusion 24 of the first item 20. Figure 4b also shows the weld portions 34 being melted, whereby rivet heads 38 have been formed. Figure 4b thus shows the first item 20 and the second item 30 being welded together.

Figure 5 schematically illustrates a welding arrangement 10 according to an embodiment of the invention. The welding arrangement 10 may be configured as the welding arrangement 10 as disclosed in Figures 2a-2c, Figure 3 or Figure 4a-4b, with the difference that in this embodiment the protrusion 24 of the first item 20 comprises a plurality of openings 26 and the second item 30 comprises a plurality of weld portions 34. The protrusion 24 may comprise a plurality of openings 26 arranged in a row in direction of the height of the protrusion 24. The weld portions 34 may be arranged in a row along a direction corresponding to the direction of the row of openings 26 in the protrusion 24 of the first item 20. In this embodiment the protrusion 24 is adapted to extend through a through hole 36 in the main portion 30’ of the second item 30, but the protrusion 24 may alternatively be adapted to be folded around an end edge of the main portion 30’ of the second item 30 as illustrated in Figure 3. The weld portions 34 are in this embodiment configured as solid cylinders but may be configured in any other way as long as the shape of the openings 26 in the protrusion 24 corresponds to the shape of the weld portions 34.

The foregoing description of the preferred embodiments of the present invention is provided for illustrative and descriptive purposes. It is not intended to be exhaustive or to restrict the invention to the variants described. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described in order best to explain the principles of the invention and its practical applications and hence make it possible for specialists to understand the invention for various embodiments and with the various modifications appropriate to the intended use.

Claims

1. A welding arrangement (10), comprising a first item (20) and a second item (30) adapted to be welded together, each item (20; 30) comprising a main portion (20’, 30’) with a first surface (21 ; 31) and a second opposed surface (22; 32), wherein the items (20; 30) are adapted to be arranged with the second surface (22) of the first item (20) abutting the first surface (31) of the second item (30), and wherein the first item (20) comprises a protrusion (24) extending from the main portion (20’), characterised in that the protrusion (24) of the first item (24) comprises at least one opening (26) and the second item (30) comprises at least one weld portion (34) projecting from the second surface (32), wherein the protrusion (24) of the first item (20) is adapted to be folded over the at least one weld portion (34) of the second item (30), such that the at least one weld portion (34) extends through the opening (26) in the protrusion (24), and wherein the at least one weld portion (34) of the second item (30) is adapted to be melted.

2. The arrangement (10) according to claim 1, wherein the main portion (30’) of the second item (30) comprises a through hole (36), through which the protrusion (24) of the first item (20) is adapted to extend.

3. The arrangement (10) according to claim 1, wherein the first item (20) is adapted to be arranged, such that the protrusion (24) is folded around an end edge (39) of the main portion (30’) of the second item (30).

4. The arrangement (10) according to any of the preceding claims, wherein the protrusion (24) of the first item (20) comprises a hinge portion (28).

5. The arrangement (10) according to any of the preceding claims, wherein the protrusion (24) of the first item (20) comprises a plurality of openings (26) and the second item (30) comprises a plurality of weld portions (34).

6. The arrangement (10) according to any of the preceding claims, wherein the at least one weld portion (34) of the second item (30) comprises a turret, a solid cylinder, a rib or a web.

7. The arrangement (10) according to any of the preceding claims, wherein the second item (30) comprises plastics and the first item (20) comprises metal or a composite material.

8. The arrangement (10) according to any of the preceding claims, wherein the protrusion (24) of the first item (20) has base (B) with a thickness which is less than 50% of the thickness of the main portion (20’) of the first item (20).

9. A vehicle (1), characterized in that it comprises a welding arrangement (10) according to any of claims 1-8 wherein the first item (20) and the second item (30) constitute parts of the vehicle (1), wherein the first surface (21) of the first item (20) is adapted to be visible from inside or outside the vehicle (1).