SE540149C2 - Panel for vehicle - Google Patents

Abstract

The disclosure concerns a vehicle panel (2) in the form of a roof air deflector (51) arranged to be positioned on the roof (41) of a vehicle (1). The panel (2) being three dimensional and comprising indentations (7) with reinforcing side walls (24) extending from the surface (23) between the indentations (7) to the bottom (25) of the indentations (7). The material thickness of the initial part of the side walls (24) is made thicker than the bottom portion (25). The disclosure also concerns a vehicle (1) comprising such vehicle panels (2) and to a method for manufacturing such vehicle panels (2).

Description

TITLE Panel for vehicle TECHNICAL FIELD The invention relates to a set of vehicle panels for mounting on a ground vehicle.

BACKGROUND ART ln order to reduce fuel consumption, weight and aerodynamic drag are two important factors.To reduce aerodynamic form drag it is previously known to include or add rigid/stiff vehiclepanels to the body structure of a vehicle such as tractor trailer trucks and trailers. Suchpanels can be placed in the front, on top, along the sides of or under the vehicle. However,such rigid vehicle panels also add weight to the vehicle or trailer, which in turn increases the fuel consumption.

DESCRIPTION OF THE INVENTION With reference to background art, there is a need to find a light weight, aerodynamic andrigid panel in order to reduce fuel consumption. The present invention relates to a rigidvehicle panel with a surface structure comprising indentations with reinforcing side wallsextending from the surface between the indentations to the bottom of the indentations. Theindentations give increased strength which has the advantage that the panel can be madethinner to reduce weight. The indentations have a further advantage because it also reducesdrag. Hence, a rigid vehicle panel comprising indentations according to the invention solves the two-folded problem with reduced drag and reduced weight.

The panel is in the form of a three dimensional material having indentations in the form ofconcave recesses on one side and corresponding elevations on the other side. Theindentations are hereinafter also called dimples. The dimples have side walls extending fromthe surface between the dimples to the bottom of the dimple. The side walls function as astructural element that reinforces the panel. lf pressure is applied towards the panel surfacethe side walls of the dimples take up the load. The bottom portion of the dimple is not subjectto as high forces as the portion of the side wall being closest to the surface between thedimples. This has the advantage that the material thickness of the initial part of the side wallsis made thicker than the bottom portion which means that with the same amount of materialin the panel, the panel is given more strength than a panel with an equally distributedmaterial thickness. The advantage of the possibility of allocating material also gives thepossibility of reducing material in general, should it be that the material thickness in the side walls are enough then the material in the bottom of the dimple could be reduced.

Furthermore, the increased strength of the panel has the advantage that less material needsto be used for the panel as a whole, which has the advantage of reduced weight. Reducedmaterial consumption also has the advantage of being more environmentally friendly and reducing cost.

Here, the surface between the dimples refers to the main surface of the vehicle panel being free from indentations.

The dimples are advantageously formed with a polygon edge or boundary line towards theflat surface between the recesses. The polygonal shape has proven to give increasedaerodynamic performance, with reduced drag for the panel in a wind tunnel. Tests haveshown very good results for an lcosagon, i.e. a polygon with 20 sides. However, otherpolygonal shapes could be possible should they have about 20 sides. A regular polygon hasbeen proven in various tests to give the stated advantages. However, it could be that thepolygon could have an irregular shape to give increased strength compared to a flat surfaceand possibly also at least an improved aerodynamic performance. Furthermore, othershapes could also be possible, for example round shaped indentations to give at leastincreased strength compared to a flat surface and possibly also at least an improvedaerodynamic performance. The interior side walls and bottom of the dimple create a shapethat can be essentially round like a part of a sphere but may also be boxy with sharp edges or a combination thereof.

According to one example, the surface structure comprises predetermined zones comprisingdimples. The position(s) of the zones are dependent on the form of the panel and on theposition of the panels on the vehicle. The zone(s) are advantageously positioned where theair velocity relative the vehicle is high. When the air velocity is high, the air pressure is high,and consequently the need for a strong structure is high. Furthermore, when the air velocityis high, there is an increased need to create a more aerodynamic panel. The dimples haveproven to give an increased aerodynamic effect in addition to increased strength of the paneL According to one example, the entire vehicle panel consists of dimples with the advantages stated above.

For both examples of dimpled zones and fully dimpled panel, the amount of dimples persurface area is advantageously more than 50% in the dimpled zones. The distance between the dimples are in the range of 1 to 50 mm, and preferably 5-20 mm, edge to edge measure.

The panel is rigid which here means that it is essentially self-supported, i.e. does not need tohave an exterior supporting structure per se. However, the panel could be mounted on asupport structure when mounted to a vehicle. Since the panel has increased strength due tothe dimples, the support structure can be reduced which in turn gives a more light weightsupport structure and thus less fuel consumption. The support structure may be reduced bybeing thinner and/or may have a reduced number of parts due to the increased strength of the panel.

The main panel body may be flat or bent, or a combination of flat and/or bent parts. Hence,the main panel body may have a two-dimensional extension, i.e. flat in a plane in a Cartesiancoordinate system, or the main panel body may have a three dimensional extension, i.e.having a surface following curvilinear coordinates. The main panel body or parts of the mainpanel body may then follow the shape of a sphere, cone, cylinder or any other three dimensional shape.

Load simulations performed in Autodesk lnventor show a possible reduction in part material volume by 30% with maintained strength compared to a flat panel without dimples.

The dimpled surface structure also creates advantageous aerodynamic performance.Aerodynamic flow simulations performed in Ansys show improved airflow and a reduction of 2,6% in form drag, Cd, compared to a panel with a flat surface structure.

According to one example, the indentation has a polygon shape with 20 sides and a diameterin the range of 1 to 100 mm, preferably 25-75 mm. The diameter refers to the longestdistance possible to measure over the dimple from edge to edge. The depth of theindentation is in the range of 0.1 to 50 mm, and preferably 2-20 mm. The edge of theindentation connecting to the main surface between the indentations of the panel may besharp or has a radius in the range of 0.1 to 10 mm, and preferably 0.1 to 5 mm. The distancebetween the indentations is in the range of 1 to 50 mm, and preferably 5-20 mm, edge toedge measure. ln a tested panel with the stated advantages, the thickness of the side wall ofthe dimples has been 3,5mm and the thickness of the bottom of the dimple has been 2,5mm.lt should be noted that this is only an example of a tested panel with the stated advantages,and the example shows that the side walls can be thicker than the bottom of the dimple withincreased strength compared to a flat panel. Hence, variations of the material thickness can be made dependent on parameters such as choice of material, desired strength of panel etc.

The dimpled panels are especially advantageous for materials that can be manufactured viamoulding. Moulding has the advantage of being a simple process per se that can becontrolled to vary the material thickness in the panel and in the dimples. The moldingprocess will be possible to control to optimize the panel for strength by having as muchmaterial as possible in the side walls and as little material as possible in the horizontalbottom as been discussed above.The preferred production process is based on: - Two liquid base components - Dosing under controlled parameters, 1:1 - Mixing of component A & B at entry of mould - Preheated metal mould - Low viscosity, low pressure build-up, ° Fast curing time - Good surface finish Specifically, one example method in a reaction injection moulding process for manufacturinga vehicle panel being three dimensional comprising indentations as discussed above,comprises the following method steps: pre-heating a metal mould having a plurality of protrusions formed on an inner surface of the mould, which protrusions are arranged for forming a plurality of indentations onthe finished panel; mixing of a first liquid polymer component and a second liquid polymer component; injecting the polymer mixture in the mould and waiting until the polymer mixture hascured into a three dimensional vehicle panel comprising indentations; and removing the finished vehicle panel from the mould.

The production process further allows long flows in the mould, making it possible to produce large parts.

According to one example, the vehicle panel includes a single top coat to be able to customize the color of the panel with as little weight added as possible.

BRIEF DESCRIPTION OF DRAWINGS The invention will below be described in connection to a number of drawings, in which: Fig. 1 schematically shows an overview of a vehicle fitted with vehicle panels; Fig. 2 schematically shows an example of a vehicle panel; Fig. 3 schematically shows an example of a vehicle panel with zones of dimples; Fig. 4 schematically shows an example of a cross section of the present surface structure invenfion; Fig. 5 schematically shows a traction unit/truck with a trailer having vehicle panels on various positions on the vehicle; Fig. 6 schematically shows a method for manufacturing a vehicle panel according to the disclosure, and in which; Fig. 7 schematically shows process equipment for manufacturing a vehicle panel according to the disclosure.

DETAILED DESCRIPTION OF DRAWINGS Various aspects of the disclosure will hereinafter be described in conjunction with theappended drawings to illustrate and not to limit the disclosure, wherein like designationsdenote like elements, and variations of the described aspects are not restricted to the specifically shown embodiments, but are applicable on other variations of the disclosure. ln the figures, like items are denoted with the same numbers.

Fig. 1 schematically shows an overview of a vehicle 1 fitted with vehicle panels 2. Accordingto one example embodiment of the disclosure one vehicle panel 2 forms a roof air deflector51 positioned on the roof 41 of a cab 4 of a vehicle 1 in the form of a traction unit 11connected to a trailer 5.The traction unit 11 is also called tractor, tractor trailer, truck andtractor trailer trucks and refers to the vehicle unit that is intended to pull the trailer 5. Fig. 1also shows an example embodiment where a vehicle panel 2 is positioned on each side 42 of the cab 4 rear of the cab doors 6 functioning as side air deflector 52.

Fig. 2 schematically shows an example of a vehicle panel 2 in form of a roof air deflector 51.The vehicle panel 2 is arranged to be mounted on a vehicle according to figure 1 and figure5. The panel 2 is an optimized custom moulded three dimensional panel comprising a largeamount of indentations 7. ln the example embodiment of fig. 2 the panel 2 in form of a roofair deflector comprises about 500 to 2000 indentations 7, specifically about 1000 to 1500 indentations 7. ln the example embodiment of fig. 2 the panel 2 in form of a roof air deflector 51 comprises afront surface 10, an inclined top surface 11 and left and right side surfaces 12, 13. Thesurfaces 10, 11, 12, 13 are interconnected to form the roof air deflector 51. The indentations7 can be located on all said surfaces10, 11, 12, 13 or only on some of said surfaces 10, 11,12, 13 depending on the circumstances. ln the example embodiment of fig.2 the indentations 7 are located on all said surfaces10, 11, 12, 13.

Fig. 3 schematically shows an example vehicle panel 7 comprising a zone 15 free ofindentations 7 and a plurality of zones 16 comprising indentations 7. The position of thezones 16 comprising indentations 7 are advantageously positioned where the air velocityrelative the vehicle is high because the dimpled zones give both increased strength and improved aerodynamic performance of the panel.

With reference to figures 1-7, the amount of the indentations per surface area is preferablymore than 50% in a dimpled zone 16, i.e. a zone 16 comprising indentations 7. ln particular,the amount of the indentations per surface area may be in the range of 50 - 90 %., in a dimpled zone 16, specifically 60 - 85 %.

Fig. 4 schematically shows an example of a cross section of a panel according to thedisclosure at a zone comprising indentations 7. The panel 2 is in the form of a threedimensional material having indentations 7 in the form of concave recesses 17 on one sideand corresponding elevations 8 on the other side. The panel 2 is preferably positioned on thevehicle such that the indentations 7 face the exterior side of the panel, i.e. engaging the airflow. ln the example embodiment of fig. 4 the indentation 7 has a polygon shape with a diameter20 in the range of 1 to 100 mm, preferably 25-75 mm. The diameter refers to the longestdistance possible to measure over the dimple from edge to edge. The depth 21 of theindentation 7 may be in the range of 0.1 to 50 mm, and preferably 2-20 mm. The edge 22 ofthe indentation 7 connecting to the main surface 23 between the indentations of the panel 2may be sharp or has a radius in the range of 0.1 to 10 mm, and preferably 0.1 to 5 mm. Thedistance 28 between the indentations 7 is in the range of 1 to 50 mm, and preferably 5-20 mm, edge to edge measure.

Each concave recess 17 in the example embodiment of fig. 4 comprises an interior side wall 24 and a bottom wall 25, wherein the interior side wall 24 has a shape that is essentially round like a part of a sphere and the bottom wall 25 is essentially flat. However, if theindentation 7 has a polygon shape, then the interior of the recess could be arranged to reflectthe polygon pattern with sections of interior side walls 24 starting at the edge/rim/boundaryline and running in a narrowing pattern towards the bottom wall 25. The narrowing sectionscould end in a point in the middle of the bottom wall 25. The curvature of the interior sidewalls 24 determines where the bottom wall 25 starts and finishes. As defined here, thebottom wall 25 is flat and the side walls 24 are curved, which means that should thenarrowing side walls be curved all the way to the end point then the bottom wall 25 becomes just a point where all the side walls meet.

The walls 24 of the indentation/dimple extend from the surface between the dimples to the bottom of the dimple and function as a structural element that reinforces the panel.

Fig. 5 schematically shows a traction unit/truck 11 with a trailer 5 having vehicle panels onvarious positions on the vehicle in addition to the panels shown in figure 1. Fig. 5schematically shows an example embodiment where a vehicle panel 2 is positioned on eachside of the cab 4 on the bottom part 43 of the traction unit 11 functioning as a truck sidefairing 53. Fig. 5 also schematically shows a further example embodiment of the vehiclepanel 2 being located on the trailer 5 being pulled by the traction unit 11. The trailer 5comprises vehicle panels 2 functioning as skirt panels 54 or trailer side fairings 54 along thelower edges 44 of the long sides of the trailer 5. The panels 2 preferably extend along a partof or the entire length of the trailer 5. Hence, figure 5 schematically shows a number ofdifferent opportunities for the vehicle panel that can be used alone in one position or in a combination of positions.

The disclosure further relates to a method for manufacturing a vehicle panel 2 according tothe disclosure. The method is referred to as reaction injection moulding and comprises aplurality of steps, as schematically illustrated in fig. 6. The method of manufacturing will also be described with reference to process equipment schematically shown in fig. 7.

A first step 60 includes providing and pre-heating a metal mould 65 having a plurality ofprotrusions formed on an inner surface of the mould, which protrusions are arranged forforming a plurality of indentations 7 on the finished vehicle panel 2. The mould thus has aninterior shape that is arranged to produce a vehicle panel 2 having a three dimensional shape.

A second step 61 involves mixing under pressure of a first liquid polymer component A and asecond liquid polymer component B. Mixing may be performed using any suitable mixingdevice 64. The dosing of the first liquid polymer component A relative to the second liquidpolymer component B may for example be controlled to about 1:1, but the dosing relationshipmay vary depending on the type of polymer components used, such as for example in therange of 1:3 - 3:1, specifically in the range of 1:2 - 2:1. The first and second liquid polymercomponents A, B include thermosetting polymers, such as dicyclopentadiene or the like. Dueto the inclusion of thermosetting resin the mixture of first and second liquid polymercomponents A, B may have a relatively low viscosity, such that large, light-weight and thin- walled items can be successfully produced.

A third step 62 includes injecting the polymer mixture into the mould 65 and waiting until thepolymer mixture has cured into a three dimensional vehicle panel 2 comprising indentations7.

A fourth step subsequently involves removing the finished vehicle panel 2 from the mould 65.

While specific examples have been described in the disclosure and illustrated in thedrawings, it will be understood by those of ordinary skill in the art that various changes maybe made, and that mixing and matching of features, elements and/or functions bet\Neenvarious examples is expressly contemplated herein so that one of ordinary skill in the artwould appreciate from this disclosure that features, elements and/or functions of oneexample may be incorporated into another example as appropriate, unless describedotherwise, above. Similarly, the method steps described in relation to the manufacturingprocess merely describe one example process, and other process steps may be added orcombined into larger steps. Therefore, it is intended that the present disclosure not be limitedto the particular examples illustrated by the drawings and described in the specification asthe best mode presently contemplated for carrying out the teachings of the presentdisclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims.

Claims (9)

1. A vehicle panel (2) in the form of a roof air deflector (51) arranged to be positioned on theroof (41) a vehicle (1), characterized in that the panel (2) being three dimensional comprisingindentations (7) with reinforcing side walls (24) extending from the surface (23) between theindentations (7) to the bottom (25) of the indentations (7), wherein the material thickness ofthe initial part of the side walls (24) is made thicker than the bottom portion (25), wherein theindentations (7) have a circular or polygon shape projected on the vehicle panel surface with a diameter or width in the range of 1 to 100 mm, and preferably 25-75 mm.

2. A vehicle panel (2) according to any one of the preceding claims, wherein the depth (21) of the indentations (7) is in the range of 0.1 to 50 mm, and preferably 2-20 mm.

3. A vehicle panel (2) according to any one of the preceding claims, wherein the edge (22) ofthe indentations (7) connecting to the essentially flat surface (23) of the panel (7) is sharp or has a radius in the range of 0.1 to 10 mm, and preferably 0_.¿.-1 to 5 mm.

4. A vehicle panel (2) according to any one of the preceding claims, wherein the side walls(24) and bottom wall (25) of the indentations (7) create a shape that is essentially round like a part of a sphere but may also be boxy with sharp edges or a combination thereof.

5. A vehicle panel (2) according to any one of the preceding claims, wherein the indentations (7) are polygonal in shape.

6. A vehicle panel (2) according to any one of the preceding claims, wherein the amount of the indentations (7) per surface area is more than 50% in a dimpled zone (16).

7. A vehicle panel (2) according to any one of the preceding claims, wherein the distance(28) between the indentations (7) are in the range of 1 to 50 mm, and preferably 5-20 mm, edge to edge measure.

8. A vehicle (1) comprising a vehicle panel (2) according to any one of claims 1-7.

9. Method for manufacturing a vehicle panel (2) according to any one of claims 1-7, being three dimensional, comprising indentations (7) and arranged to be mounted on a vehicle (1) in a reaction injection moulding process, the method comprising: pre-heating a metal mould having a plurality of protrusions formed on an innersurface of the mould, Which protrusions are arranged for forming a plurality of indentations(7) on the finished panel (2); mixing of a first liquid polymer component and a second liquid polymer component; injecting the polymer mixture in the mould and waiting until the polymer mixture hascured into a three dimensional vehicle panel (2) comprising indentations (7); and removing the finished vehicle panel (2) from the mould.