Reinforcement for vehicle door and methods of manufacture

Abstract

The present disclosure relates to a vehicle door comprising an inner panel, an outer panel, and a reinforcement member. The inner panel has a lower part substantially adapted to a shape of a rocker. The lower part comprises a stepped portion including a top tread configured to be arranged on top of a portion of the rocker, a riser configured to be arranged next to a portion of the rocker, and a bottom tread. The reinforcement member is arranged between the inner and outer panel, and is arranged substantially on top of the bottom tread, and extends vertically substantially along the height of the riser. The reinforcement member forms a closed cross-section.

Description

REINFORCEMENT FOR VEHICLE DOOR AND METHODS OF MANUFACTURE

[0001] The present application claims the benefit of European patent application n° 23 383 303.7 filed on December 15th, 2023.

[0002] The present disclosure relates to vehicle doors and reinforcement members for vehicle doors. The present disclosure further relates to methods for manufacturing such reinforcements.BACKGROUND

[0003] Vehicles such as cars incorporate a structural skeleton designed to withstand the loads that the vehicle may be subjected to during its lifetime. The structural skeleton is further designed to withstand and absorb impacts, in case of e.g. collisions with other cars or road structures.

[0004] The demand for weight reduction in the automotive industry has led to the development and implementation of lightweight materials or components, and related manufacturing processes and tools. The demand for weight reduction is especially driven by the goal of a reduction of CO2 emissions. The growing concern for occupant safety also leads to the adoption of materials which improve the integrity of the vehicle during a crash while also improving the energy absorption.

[0005] A process known as Hot Forming Die Quenching (HFDQ) typically uses boron steel sheets to create stamped components with Ultra High Strength Steel (UHSS) properties, with tensile strengths of e.g. 1.500 MPa or 2.000 MPa or even more. The increase in strength allows for a thinner gauge material to be used, which results in weight savings over conventionally cold stamped mild steel components. Throughout the present disclosure UHSS may be regarded as a steel having an ultimate tensile strength of 1.000 MPa or more after a press hardening process.

[0006] In a HFDQ process, a blank to be hot formed may be heated to a predetermined temperature e.g. austenization temperature or higher (and particularly between Ac3 and an evaporation temperature of e.g. a coating of the blank). A furnace system may be used for thispurpose. Depending on the specific needs, a furnace system may be complemented with additional heaters, e.g. induction heaters or infrared heaters. By heating the blank, the strength of the blank decreases, and deformability increases i.e. to facilitate the hot stamping process.

[0007] There are several known Ultra High Strength steels (UHSS) for hot stamping and hardening. The blank may be made e.g. of a boron steel, coated or uncoated, such as Usibor® 1500 (22MnB5) commercially available from ArcelorMittal. Other high strength materials such as 37MnB5 may also be used. UHSS may exhibit tensile strengths as high as 1 .500 MPa, or even 2.000 MPa or more, particularly after a press hardening operation.

[0008] In addition to the Ultra High Strength Steels mentioned before, more ductile steels may be used in parts of the structural skeleton requiring energy absorption. Examples of ductile steels include Ductibor® 500, Ductibor ® 1000 and CRL-340LA.

[0009] Hot Forming Die Quenching may also be called “press hardening” or “hot stamping”. These terms will be used interchangeably throughout the present disclosure.

[0010] Typical vehicle components that may be manufactured using the HFDQ process include door beams, bumper beams, cross / side members, A / B pillar reinforcements, front and rear rails, seat crossmembers and roof rails.

[0011] The door structure of a car is an integral part of the vehicle structural system. A vehicle door structure may perform inter alia the following functions: the door provides structural resistance against intrusion from other vehicles or objects, and may be configured to absorb energy and transfer loads in an appropriate manner to other areas of the vehicle and is generally designed to keep occupants safely inside the vehicle. At the same time, the door provides attaching surfaces for mechanisms, wiring, sensing devices, seals and interior trim. In addition, the door of course keeps the vehicle closed to the outside environment.

[0012] Structurally, vehicle doors such as car doors may comprise an inner panel (a panel arranged to face an “inside” of the vehicle), an outer panel (a panel facing the outside of the vehicle), and a so-called “shield” in between the outer and inner panels. The shield may be regarded as formed by a plurality of reinforcements. These are generally denominated shield, since (like a shield) they protect the vehicle and its occupants.

[0013] The shield may comprise an inner shield, and an outer shield. The inner shield may be considered to comprise all elements between the inner panel and window glass. The outer shield may be considered to comprise all elements between the outer panel and the window glass. The inner shield may carry and guide the window glass, as well as electronic systems(e.g. motor for lowering and raising the window). The outer shield in particular may include a Side Impact Protection Beam (SIPB).

[0014] A SIPB can be manufactured by hot stamping of LIHSS material and is typically arranged diagonally across the vehicle door. The SIPB may have a U-shaped (or “hat-shaped”) cross-section. Parts of the inner panel and outer panel may be hot stamped, but significant parts of the panels may be cold formed and may have a lower ultimate tensile strength than e.g. the SIPB. The SIPB may be regarded as the most important structural element inside the vehicle door to protect vehicle passengers in the case of a crash or impact. In case of a side impact, also the B-pillar, and the rocker are particularly important.

[0015] JP6764293B2 discloses a vehicle door capable of reducing dependance on a door beam for absorbing a load. The vehicle door is attached to a vehicle body, and comprises: panel parts arranged inside and outside a cabin, respectively; a frame part arranged between the panel parts; and a reinforce part connected with the frame part.

[0016] US 5,066,064 discloses A vehicle door, for a passenger automobile which in the closed position has its door frame juxtaposed with the outwardly facing part of the threshold for the door opening of the vehicle body, is provided at the level of this threshold with a horizontal strut which can be corrugated for controlled collapse and extends normal to the door plane.

[0017] US 2014 / 0319869 discloses A door for selectively opening and closing at least a portion of an opening in a vehicle includes an outer door panel and an inner door panel. The inner panel is attached to the outer panel thus defining a space between the inner and outer panels. The inner panel is characterized by height and length. A reinforcement beam having a length substantially equal to the length of the inner panel is attached to the inner panel such that the beam is disposed in the defined space. A reinforcement bracket having a height and a length is attached to the inner panel intermediate the first and second ends of the length of the inner panel such that the beam is disposed in the space between the inner and outer panels. The length of the bracket is smaller than the length of the reinforcement beam.

[0018] Recently, the requirements and expectations from OEM’s and others for vehicles in terms of side impact crashworthiness have increased. As a specific example, the requirements of crashworthiness have become more demanding with respect to a moving deformable barrier (MDB). In particular, both impact velocity and mass of the MDB used in tests that the structure needs to withstand have been increased. Unless specific measures are taken it can be estimated that the intrusion of the door to the inside of the vehicle increases by e.g. 20 - 30% due to the increased mass and velocity used in the reference tests.

[0019] Car manufacturers and car part manufacturers have to deal with the more demanding requirements. These requirements are potentially even more demanding in the case of electric or hybrid vehicles comprising a traction battery. Intrusion into the area of the battery is to be avoided because of e.g. fire risk in case of damaged battery cells.

[0020] One solution that has been explored is to increase the strength of the SIPB. In particular, the dimensions, specifically the thickness, of the part may be increased. Or the cross-section of the SIPB can be changed, e.g. by changing the cross-section from an open cross-section (U-shape or double U-shape) to a closed cross-section (either by providing a cover plate to close the cross-section or by changing the manufacturing process to obtain a closed cross-section). It may further be attempted to reinforce the SIPB by choosing a higher grade material.

[0021] Yet other solutions focus on increasing weight and strength of the rocker, e.g. by adding reinforcements or by increasing thickness. These solutions may lead to a significant weight increase though.

[0022] It is an object of the present disclosure to provide door structures that are able to withstand increasingly high requirements in terms of crashworthiness without unduly increasing the overall weight of the structure.SUMMARY

[0023] In a first aspect, a vehicle door is provided, which comprises an inner panel, an outer panel, and a reinforcement member. The inner panel has a lower part substantially adapted to a shape of a rocker, the lower part comprising a stepped portion including a top tread configured to be arranged on top of a portion of the rocker, a riser configured to be arranged next to a portion of the rocker, and a bottom tread. The reinforcement member is arranged between the inner and outer panel, and is arranged substantially on top of the bottom tread, and extends vertically substantially along a height of the riser, and the reinforcement member forms a closed cross-section.

[0024] In accordance with this aspect, a vehicle door is provided with an improved design in terms of crashworthiness in case of a side impact at a reduced weight. The reinforcement member is provided in a generally available space in front of the rocker. Providing the reinforcement member in a manner that is supported by the rocker has the effect of the rocker retaining the reinforcement member and thereby significantly reducing the intrusion in case of side impact. Safety for vehicle occupants is thus improved.

[0025] In some examples, the reinforcement member extends along a longitudinal direction substantially from a front raised portion of the inner panel to a rear raised portion of the inner panel and the reinforcement member has an upward extending front portion and / or an upward extending rear portion. It has been found that an upward front portion and / or upward rear portion significantly affects the “retention” effect hereinbefore described, and thus further reduces intrusion.

[0026] In some examples, the reinforcement member is a tubular component having a closed cross-section. The closed cross-section is thus formed by the reinforcement member itself. The tubular component may be made in particular by hydroforming.

[0027] In other examples, the reinforcement member comprises two substantially L-shaped profiles, which are attached to each other to form a closed-cross-section. In an alternative manufacturing method, the reinforcement member may be assembled by joining (e.g. welding) two hot stamped profiles. Improved results in case of a side impact can also be obtained in this manner.

[0028] In further examples, the reinforcement member comprises an L-shaped profile attached to the inner panel, wherein the L-shaped profile forms the closed cross-section together with the inner panel.

[0029] In a further aspect, a vehicle is provided which comprises a vehicle door of any of the examples of the first aspect.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Non-limiting examples of the present disclosure will be described in the following, with reference to the appended figures, in which:Figure 1 A schematically illustrates an exploded view of a prior art vehicle door;Figure 1 B illustrates an isometric view of an inner panel of a vehicle door;Figures 2A - 2D schematically illustrates an example of a vehicle door with an example of a reinforcement member;Figures 3A - 3B schematically illustrate a deformation of a vehicle door in case of a side impact;Figures 3C - 3D schematically illustrate a deformation of a vehicle door according to an example of the present disclosure in case of a side impact;Figures 4A - 4B schematically illustrate further examples of reinforcement members; andFigure 5 schematically illustrates a cross-sectional view of another example of a vehicle door.

[0031] The figures refer to example implementations and are only be used as an aid for understanding the claimed subject matter, not for limiting it in any sense.DETAILED DESCRIPTION OF EXAMPLES

[0032] Figure 1 A schematically illustrates an exploded view of a vehicle door. The vehicle door 100 of this example has an inner panel 10. The inner panel 10 may be regarded as a structural member of the vehicle door and is the panel that is facing the inside of the vehicle. The inner panel 10 may be manufactured using a variety of techniques and materials. A known inner panel 10 may be made by cold stamping of steel.

[0033] A bottom part of the inner panel 10 may be adapted to the shape of the rocker. Although not shown in figure 1A, in a zone 8, the rocker may be arranged.

[0034] The vehicle door 100 in this example further comprises an inner shield 30, a window glass 40, a side impact protection beam 50, and an outer panel 60. The inner shield 30 may serve to hold and support the window glass and electronic components such as e.g. a motor to drive movement of the window glass 40, or a loudspeaker. The side impact protection beam 50 may form the most important component to limit intrusion in the case of a side impact and to protect vehicle occupants. The outer panel 60 is a structural member facing an outside of the vehicle, and like the inner panel may typically be made of cold stamped steel.

[0035] Figure 1 B indicates a lower part of the inner panel of the vehicle door. It may be seen that the lower part of the inner panel 10 of the vehicle door may be adapted, in terms of shape, to the shape of the rocker i.e., the shape of the inner panel has a shape that “fits” together with the rocker. The inner panel may thus comprise a stepped portion 12. The inner panel may further have raised portions 14 and 16 towards the front and rear of the vehicle door. The raised portions 14 and 16 of the inner panel may be adapted to a shape of e.g. a hinge pillar and B-pillar.

[0036] Figures 2A - 2D schematically illustrate an example of a vehicle door with an example of a reinforcement member. Figure 2A provides a side view of a vehicle door. Figures 2B and 2C show cross-sectional view of a reinforcement member 80, and inner panel 10, and of the vehicle door respectively. Figure 2D show two further views of reinforcement member 80 if the example of figure 2A.

[0037] In one aspect, the present disclosure provides a vehicle door. The vehicle door comprises an inner panel, an outer panel, and a reinforcement member 80. The vehicle door in the example of figure 2 further includes a side impact protection beam. The side impact protection beam is arranged diagonally across the vehicle door and can be manufactured by hot stamping of LIHSS material, e.g. llsibor® 1500 P.

[0038] The inner panel has a lower part substantially adapted to a shape of a rocker. Figure 2B shows the lower part of the inner panel in cross section. On the right hand side of figure 2B in this example, the rocker (not shown) would be provided. The inner panel may be made e.g. by cold stamping.

[0039] The lower part of the inner panel comprises a stepped portion including a top tread 22 (which may be substantially horizontal) configured to be arranged on top of a portion of the rocker, a riser 24 configured to be arranged next to a portion of the rocker (and which may be substantially vertical), and a bottom tread 26 (which may be substantially horizontal). It will be clear that the riser does not need to be perfectly vertical, and the top and bottom treads do not need to be perfectly horizontal. There is also no need for the portions to be perfectly perpendicular to each other. Many different shapes of rockers are known, and the lower part of the inner panel can be suitably adapted to the specific shape and size chosen for the rocker.

[0040] The reinforcement member 80 is arranged between the inner and outer panel, and is arranged substantially on top of the bottom tread 26, and extends vertically substantially along the height of the riser 24. The reinforcement member may be slightly higher than a height of the riser, but may also be lower than a height of the riser. The height of the reinforcement member is preferably similar to the height of the riser so that advantage is effectively taken of the support provided by the rocker.

[0041] The reinforcement member forms a closed cross-section as may be seen particularly in figures 2B and 2C. In the illustrated example, the reinforcement member extends along a longitudinal direction substantially from a front raised portion of the inner panel to a rear raised portion of the inner panel. The longitudinal direction in this case is in line with a direction of the vehicle when the door is closed. In other examples, the length of the reinforcement member may be shorter in order to reduce weight. An increased length of the reinforcement member can improve the behavior in the case of crash.

[0042] In preferred examples, the reinforcement member may have an upward extending front portion 82 and / or an upward extending rear portion 84. I.e. in these examples, the reinforcement member 80 lies against a front and / or rear raised portion of the inner panel.Such upward extending portions 82, 84 can improve the effect of retaining the door by the rocker as will be illustrated further herein.

[0043] In some examples, an internal reinforcement may be arranged inside the rocker. E.g. an extruded aluminum reinforcement member having one or more hexagonal cells, or a wave shaped reinforcement member such as disclosed in WO2021244792A1. In examples, the internal reinforcement inside the rocker may be arranged at a height corresponding to the riser 24. The internal reinforcement inside the rocker can absorb more energy in case of an impact and retain reinforcement member 80.

[0044] The reinforcement member 80 may be welded to the inner panel. In a specific example, laser stitches may be used. In a more specific example, laser stitching the reinforcement member to the inner panel with a stitch length of e.g. 3 - 5 cm may be used. In further examples, other joining methods may be used including Mig welding, resistance spot welding, adhesive bonding, and the use of mechanical fasteners (e.g. rivets).

[0045] In the illustrated example of figure 2, the reinforcement member 80 is a tubular component having a closed cross-section. The tubular component may be made particularly by hydroforming. The tubular components may be made from an Ultra High Strength Steel (UHSS), or from aluminium or aluminium alloy material.

[0046] Suitable steels include e.g. Fortiform ® 1180 (HF1180Y850) or Fortiform ® 1270 as commercially available from ArcelorMittal®. Such steels may have a relatively high yield strength (after forming) of 850 - 1060 MPa or 1.100 - 1.310 MPa respectively. It has been found that a yield strength of 700 MPa or more, specifically 800 MPa or more is very advantageous for the reduction of intrusion by the reinforcement member.

[0047] Fortiform ® 1180 has the following composition (by weight percentages):Maximum carbon (C) (%) : 0.25Maximum silicon (Si) (%) : 2.2Maximum manganese (Mn) (%): 3.0Maximum phosphorus (P) (%): 0.05Maximum sulphur (S) (%): 0.01Aluminium (Al) (%): 0.015 - 2.0Maximum copper (Cu) (%): 0.20Maximum boron (B) (%): 0.005Maximum titanium (Ti) and niobium (Nb) (%): 0.15Maximum chromium (Cr) (%) + Molybdenum (Mo) (%): 1.4

[0048] Fortiform ® 1270 has the following composition (by weight percentages):Maximum carbon (C) (%) : 0.26Maximum silicon (Si) (%) : 2.2Maximum manganese (Mn) (%): 4.5Maximum phosphorus (P) (%): 0.05Maximum sulphur (S) (%): 0.01Aluminium (Al) (%): 0.015 - 2.0Maximum copper (Cu) (%): 0.20Maximum boron (B) (%): 0.005Maximum titanium (Ti) and niobium (Nb) (%): 0.15Maximum chromium (Cr) (%) + Molybdenum (Mo) (%): 1.4

[0049] Further suitable steels include dual phase steels e.g. DP1000 having a tensile strength of around 1 .000 MPa and a yield strength of around 660 MPa.

[0050] In this example, hydroforming was proposed for the manufacture of the tubular member. In another example, extrusion may be used. In specific example, extrusion of an aluminum may be used for manufacturing the tubular member.

[0051] Figures 3A illustrates a behavior of a vehicle door in the case of a side impact. Figure 3B shows a more detailed view of a part of figure 3A. Figures 3C and 3D schematically illustrate the deformation of the behavior of a vehicle door with a reinforcement such as the one illustrated in figure 2.

[0052] It may be seen in figure 3 that the intrusion of the side impact beam is reduced, and also that the deformation at the front hinges (particularly the lower hinge) is significantly reduced. The reinforcement member is retained by the rocker which reduces the intrusion.

[0053] Figures 4A - 4B schematically illustrate further examples of reinforcement members. In both examples, the reinforcement member may be tubular. In the example of figure 4A, the weight is reduced (as compared to the example of figures 2 and 3) by shortening the length of the reinforcement member. The reinforcement member in this example does not include the raised portions at the front and at the rear of the reinforcement member.

[0054] The example of figure 4B illustrates that the reinforcement member may have one or more corrugated surfaces. In the example of figure 4B, the outer face of the reinforcement member (the side of the reinforcement member facing towards the outside of the vehicle) has a corrugated surface. In this example, the outer surface of the reinforcement member has sections bulging outward and other sections bulging inwards.

[0055] In further examples, the upper face of the reinforcement member is corrugated and has sections bulging upward and sections bulging downwards. These examples may also be combined in yet a further example.

[0056] Figure 5 illustrates yet a further example, wherein the reinforcement member 90 comprises an L-shaped profile which is attached to the inner panel, such that the L-shaped profile forms a closed cross-section 85 together with inner panel.

[0057] As before, the inner panel comprises a stepped portion to adapt the shape to a rocker (not shown) provided in the area 8. The stepped portion comprises a first read 22, a riser 24 and a second tread 26. The L-shaped profile may be attached (e.g. welded) at a flange 94 in an area of the first tread 22 of the stepped portion and also below the second tread 26. Laser welding or spot welding may be used.

[0058] The L-shaped profile may be may by hot stamping. In some examples, the reinforcement member 90 may be made of a boron steel like Usibor®, e.g. Usibor® 1500 (or any 22MnB5 steel with or without protective coating), Usibor® 2000 (or any 37MnB5 steel) or any martensitic steel or ultra-high strength steel (UHSS). Usibor® is commercially available from ArcelorMittal.

[0059] Usibor® 1500 is supplied in ferritic-perlitic phase. It is a fine grain structure distributed in a homogenous pattern. Its mechanical properties are related to this structure. After heating, a hot stamping process and subsequent quenching, a martensite microstructure is created. As a result, tensile strength and yield strength increase noticeably.

[0060] The composition of Usibor® 1500 is summarized below in weight percentages (the rest is iron (Fe) and impurities):Maximum carbon (C) (%) : 0.25Maximum silicon (Si) (%) : 0.4Maximum manganese (Mn) (%): 1.4Maximum phosphorus (P) (%): 0.03Maximum sulphur (S) (%): 0.01Aluminium (Al) (%): 0.01 - 0.1Maximum titanium (Ti) (%): 0.05Maximum niobium (Nb) (%): 0.01Maximum copper (Cu) (%): 0.20Maximum boron (B) (%): 0.005Maximum chromium (Cr) (%): 0.35

[0061] llsibor® 2000 is another boron steel with even higher strength. After a hot stamping die quenching process, the yield strength of llsibor® 2000 may be 1300 MPa or more, and its ultimate tensile strength may be above 1800 MPa.

[0062] The composition of Usibor® 2000 is summarized below in weight percentages (rest is iron (Fe) and impurities):Maximum carbon (C) (%): 0.36Maximum silicon (Si) (%): 0.8Maximum manganese (Mn) (%): 0.8Maximum phosphorus (P) (%): 0.03Maximum sulphur (S) (%): 0.01Aluminium (Al) (%): 0.01 - 0.06Maximum titanium (Ti) (%): 0.07Maximum niobium (Nb) (%): 0.07Maximum copper (Cu) (%): 0.20Maximum boron (B) (%): 0.005Maximum chromium (Cr) (%): 0.50Maximum molybdenum (Mb) (%): 0.50

[0063] 22MnB5 may be presented with an aluminum-silicon coating in order to avoid decarburization and scale formation during the forming process.

[0064] Several 22MnB5 steels are commercially available having a similar chemical composition. However, the exact amount of each of the components in a 22MnB5 steel may vary slightly from one manufacturer to another. Other ultra-high strength steels include e.g. BTR 165, commercially available from Benteler.

[0065] Hot forming of boron steels is becoming increasingly popular in the automotive industry due to their excellent strength and formability. Many structural components that were traditionally cold formed from mild steel are thus being replaced with hot formed equivalents that offer a significant increase in strength. This allows for reductions in material thickness (and thus weight) while maintaining the same strength.

[0066] Hot formed components offer very low levels of ductility and energy absorption in the as-formed condition. In order to improve the ductility and energy absorption in specific areas of a component, it is known to introduce softer regions within the same component. This improves ductility locally while maintaining the required high strength overall. By locally tailoring the microstructure and mechanical properties of certain structural components such that they comprise regions with very high strength (very hard), i.e. high ultimate tensile strength and high yield strength and regions with increased ductility (softer), i.e. lower ultimate tensile strength and lower yield strength and increased elongation before break, it may be possible to improve their overall energy absorption and maintain their structural integrity during a crash situation and also reduce their overall weight. Such soft zones may also advantageously change the kinematic behavior in case of a collapse of a component under an impact.

[0067] Known methods of creating regions with increased ductility ("softzones" or "soft zones") in structural components of vehicles include the provision of tools comprising a pair of complementary upper and lower die units, each of the units having separate die elements (steel blocks). A blank to be hot formed is previously heated to a predetermined temperature e.g. austenization temperature or higher by, for example, a furnace system so as to reduce the strength i.e. to facilitate the hot stamping process.

[0068] The die elements may be designed to work at different temperatures, in order to have different cooling rates in different zones of the part being formed during the quenching process, and thereby resulting in different material properties in the final product e.g. soft areas which will generally have a lower ultimate tensile strength and a lower yield strength but allow for more elongation before breaking. E.g. one die element may be cooled in order to quench the corresponding area of the component being manufactured at high cooling rates and to thereby reduce the temperature of the component rapidly and obtain a hard martensitic microstructure. Another neighboring die element may be heated in order to ensure that the corresponding portion of the component being manufactured cools down at a lower cooling rate, in order to obtain a softer microstructure, including e.g. bainite, ferrite and / or perlite. Such an area of the component may remain at higher temperatures than the rest of the component when it leaves the die.

[0069] Other methods for obtaining hot stamped components with areas of different mechanical properties include e.g. tailored or differentiated heating prior to stamping, and local heat treatments after a stamping process to change the local microstructure and obtain different mechanical properties. Yet further possibilities include the use of patchwork blanks, and Tailor Welded Blanks (TWB) combining different thicknesses and / or materials in blanks.

[0070] Several methods of differential heating prior to stamping are known. In an example, a nozzle or set of nozzles may discharge a fluid stream, e.g. compressed cooling air, towards a portion of the blank to be cooled e.g. while the bank is still in a furnace system. Other parts of the blank may be maintained at a higher temperature. This makes it possible to obtain a blank with a tailored temperature profile along its length and / or width. In some examples, the blank may undergo further heating in the oven before being subjected to the stamping process.

[0071] The reinforcement member 90 providing closed cross-section 85 in the herein illustrated manner can also significantly reduce intrusion in the case of a side impact.

[0072] In yet a further (non-illustrated) example, the reinforcement member comprises two substantially L-shaped profiles, which are attached to each other to form a closed-cross- section. I.e. in such an example, the closed cross-section is provided by the reinforcement member itself. Both the profiles may be made by hot stamping in accordance with the processes hereinbefore described.

[0073] The L-shaped profiles may be joined at appropriate flanges, e.g. by welding. Similar results as for the tubular reinforcement member of figures 2 and 3 may be obtained in terms of intrusion reduction.

[0074] In further non-illustrated examples, an aluminum extruded profile may be provided inside the closed cross-section. An aluminum extrusion can be lightweight, easy to manufacture and can reduce deformation of the reinforcement member to further reduce intrusion in the case of a side impact.

[0075] In yet further non-illustrated examples, other reinforcements inside the closed crosssection may be provided. Such reinforcements may be made of steel. Such reinforcements in some examples may include a plurality of honeycomb like cells.

[0076] Although only a number of examples have been disclosed herein, other alternatives, modifications, uses and / or equivalents thereof are possible. Furthermore, all possible combinations of the described examples are also covered. Thus, the scope of the present disclosure should not be limited by particular examples, but should be determined only by a fair reading of the claims that follow.

Claims

CLAIMS1 . A vehicle door comprising: an inner panel; an outer panel; a diagonally extending side impact protection beam; and a reinforcement member; the inner panel having a lower part substantially adapted to a shape of a rocker, the lower part comprising a stepped portion including a top tread configured to be arranged on top of a portion of the rocker, a riser configured to be arranged next to a portion of the rocker, and a bottom tread, wherein the reinforcement member is arranged between the inner and outer panel, and is arranged substantially on top of the bottom tread, and extends vertically substantially along the height of the riser, and wherein the reinforcement member forms a closed cross-section.

2. The vehicle door of claim 1 , wherein the reinforcement member extends along a longitudinal direction substantially from a front raised portion of the inner panel to a rear raised portion of the inner panel.

3. The vehicle door of claim 2, wherein the reinforcement member has an upward extending front portion and / or an upward extending rear portion.

4. The vehicle door of any of claims 1 - 3, wherein the reinforcement member is welded to the inner panel, specifically using laser stitches.

5. The vehicle door of any of claims 1 - 4, further comprising an aluminum extruded profile inside the closed cross-section.

6. The vehicle door of any of claims 1 - 5, wherein the reinforcement member has a corrugated outer surface.

7. The vehicle door of any of claims 1 - 6, wherein the reinforcement member is a tubular component having a closed cross-section.

8. The vehicle door of claim 7, wherein the tubular component is made by hydroforming.

9. The vehicle door of claim 7 or 8, wherein the tubular components is made from an Ultra High Strength Steel (UHSS), or from aluminium or aluminium alloy material.

10. The vehicle door of claim 7, wherein the tubular component is made by extrusion, and optionally wherein the tubular component is an aluminum extrusion.11 . The vehicle door of any of claims 1- 7, wherein the reinforcement member comprises two substantially L-shaped profiles, which are attached to each other to form a closed-cross- section.

12. The vehicle door of claim 11 , wherein the L-shaped profiles are made by hot stamping.

13. The vehicle door of any of claims 1 - 7, wherein the reinforcement member comprises an L-shaped profile attached to the inner panel, wherein the L-shaped profile forms the closed cross-section together with the inner panel.

14. The vehicle door of any of claims 1 - 13, wherein the side impact protection beam is made from hot stamped UHSS.

15. A vehicle comprising the vehicle door of any of claims 1 - 14.

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