Rocker arm assembly for vehicle and method of manufacture

Abstract

A rocker arm assembly (10) for a vehicle includes a rocker arm (20) and a rocker arm reinforcement (30) inside the rocker arm. The present disclosure also relates to a method (100) for manufacturing a rocker arm assembly for a vehicle. A rocker arm assembly (10) for a vehicle includes: a rocker arm (20) including an outer panel (11) and an inner panel (12); and an elongate reinforcement (30) extending inside the rocker arm along a longitudinal direction (40) of the rocker arm. The reinforcement (30) includes an outer portion (31) configured to absorb energy during a side impact and an inner portion (32) configured to offset a lateral impact load across a battery of the vehicle.

Description

Technical Field

[0001] This application claims the benefit of European patent application No. 22382910.2 filed on September 30, 2022.

[0002] The present disclosure relates to a rocker assembly for a vehicle, comprising a rocker and a rocker reinforcement inside the rocker. The present disclosure also relates to a method for manufacturing a rocker assembly for a vehicle. The present disclosure particularly relates to a rocker and a rocker reinforcement for an electric vehicle or a hybrid vehicle. Background Art

[0003] Vehicles such as cars incorporate a structural frame designed to withstand all loads that the vehicle may be subjected to during its life. The structural frame or "body in white" (BIW) is also designed to withstand and absorb impacts in the event of a collision with another car, for example. The structural frame is also designed to be as light as possible in order to reduce pollutants such as CO 2 emissions to the environment or reducing electricity consumption in electric vehicles.

[0004] The structural framework or BIW of an automobile may include, for example, impact beams, pillars (e.g., A-pillars, B-pillars, C-pillars), side impact protection beams, and rocker panels. These and other structural members may have one or more regions having a generally U-shaped (also referred to as a "hat" shaped) cross-section. These structural members may be manufactured in a variety of ways and may be made from a variety of materials. For example, a rocker panel may be made from steel, particularly ultra-high strength steel (UHSS), and may be manufactured by press hardening.

[0005] Ultra-high strength steel (UHSS) exhibits optimized maximum strength per unit weight and favorable formability for the structural frame of a vehicle or at least parts thereof in the automotive industry. In the present disclosure, UHSS may be considered to be a steel having a maximum tensile strength (after hot stamping) of at least 1000 MPa, preferably at most about 1500 MPa or at most 2000 MPa or more. An example of UHSS used in the automotive industry is 22MnB5 steel.

[0006] Processing components for vehicles can include forming metal sheets, in particular steel sheets, so that the sheets have the desired shape. One method used in particular in the automotive industry is hot forming die quenching (HFDQ). In the HFDQ method, the steel blank is heated to above the austenitizing temperature, above Ac1 or above Ac3. After heating to above the austenitizing temperature, the blank is placed in a hot forming press. The blank is deformed and quenched (cooled quickly) at the same time. Cooling can usually be carried out at a rate higher than the so-called critical cooling rate. The critical cooling rate of steel in HFDQ can be about 27°C / s. As a result of quenching, the deformed blank can obtain a martensitic microstructure. Depending on the exact temperature and heating time, a fully martensitic microstructure can be obtained. The product obtained in this way can obtain a high hardness, and a correspondingly high ultimate tensile strength, and a high yield strength. On the other hand, the maximum elongation (elongation at break) can be relatively low.

[0007] Tailored heating or tailored in-die cooling can be used to provide so-called "soft zones", i.e., regions of higher ductility and lower ultimate tensile and yield strengths. The microstructure in these regions may not be fully martensitic due to selective heating (e.g., not all regions of the billet are heated to the austenitizing temperature) or due to tailored cooling (e.g., not all regions are cooled at the same cooling rate). They may include one or more of martensite, bainite, ferrite, and pearlite, depending on the heat treatment they are subjected to.

[0008] In addition to tailored heating or cooling, partial heat treatments after HFDQ can also be used. For example, an induction heater or a laser can be used to locally heat treat areas of the press-hardened product. The heating time, maximum temperature and cooling rate can be adapted to obtain the desired mechanical properties in terms of ductility, hardness, yield strength, etc. and the corresponding microstructure.

[0009] The rocker is located along the side of the vehicle below the opening for the door and extends between the front wheel opening and the rear wheel opening. The rocker is sometimes referred to as a "rocker panel". The rocker typically comprises two parts or panels, an inner rocker panel and an outer rocker panel, which are joined to each other at respective flanges along the longitudinal direction of the rocker (and therefore also along the longitudinal direction of the vehicle). The inner rocker panel faces towards the interior of the vehicle, while the outer rocker panel faces away from the vehicle. The rocker is important for absorbing sufficient energy while avoiding excessive intrusion of the side of the vehicle during a collision, in particular in lateral collisions. The performance of the rocker, for example in terms of energy absorption and intrusion, can be tested using tests such as Euro NCAP.

[0010] The rapid development of electric vehicles (EVs) and hybrid vehicles has forced the industry to design new vehicle components, for example, for weight reduction to achieve improved vehicle range, and for housing and protecting new vehicle components, etc. Structural components with new geometries and alternative materials are being manufactured and integrated into EVs to achieve safety and weight reduction goals.

[0011] Traction batteries are an important part of EVs and hybrid vehicles that provide power to the vehicle's electric motor. The electronic and chemical properties of these batteries make them particularly sensitive to high mechanical loads, such as crash impacts. In order to extend the battery life and protect them from external impacts, the automotive industry has put considerable effort into providing battery housings and load-bearing structures suitable for EVs. As a result, over the past few years, a wide variety of protective elements have been designed and engineered to house and protect traction batteries.

[0012] The rocker arm can be used not only to protect the passengers in the vehicle, but also to protect the battery box in an electric or hybrid vehicle. The battery box is usually arranged at the bottom of the vehicle, extending between the front and rear axles of the vehicle. It is configured to support and contain the battery pack of the vehicle. If the vehicle is involved in a collision, especially a collision with the side of the vehicle, the rocker arm can avoid or at least reduce damage to the battery box. The rocker arm should be able to absorb as much energy as possible to maximize the battery box protection.

[0013] One way to enhance energy absorption while providing a sufficient level of deformation to the rocker arm may be to add reinforcements to the rocker arm, such as between the inner rocker arm and the outer rocker arm panel. Optimizing the materials, geometry and means of attaching the rocker arm reinforcement to the rocker arm is important to improving energy absorption and integrity of the rocker arm during a lateral impact while maintaining a low weight component.

[0014] An object of the present disclosure is to provide improvements to rocker reinforcements. Summary of the invention

[0015] Throughout the present disclosure, longitudinal, vertical and transverse directions are defined for providing spatial orientation of a rocker arm and a rocker arm reinforcement attached thereto. These directions are substantially perpendicular to each other. Thus, the rocker arm has a length in the longitudinal direction (the longitudinal direction will be parallel to the direction of travel of the vehicle in which the rocker arm is mounted), a height in the vertical direction and a width in the transverse direction; a cross-section of the rocker arm is defined by a plane substantially perpendicular to the longitudinal direction and therefore includes a vertical direction and a transverse direction. Similarly, the rocker arm reinforcement has a length in the longitudinal direction, a height in the vertical direction and a width in the transverse direction; and a cross-section of the rocker arm reinforcement is substantially perpendicular to the longitudinal direction and includes a vertical direction and a transverse direction.

[0016] Thus, for example during a vehicle collision or when a pole is on the road, when the rocker is subjected to a lateral impact and thus to a lateral impact load, in standardized crash tests the lateral impact may be assumed to be substantially in a transverse direction. In practice, the impact may include at least a component substantially parallel to the transverse direction.

[0017] In a frontal impact or SORB ("Small Overlap Rigid Barrier") test, it may be assumed that the impact is substantially in the longitudinal direction according to the above definition. In the present disclosure, the focus will be primarily on lateral impacts.

[0018] In one aspect of the present disclosure, a rocker assembly for a vehicle is provided. The rocker assembly includes a rocker, the rocker including an outer panel configured to withstand a lateral impact load and an inner panel configured to transfer the lateral impact load to an internal structure of the vehicle. The rocker assembly also includes a reinforcement inside the rocker between the inner panel and the outer panel. The rocker reinforcement extends along the longitudinal direction of the rocker and defines a unit structure along at least a portion of the rocker in a cross section perpendicular to the longitudinal direction of the rocker. The unit structure includes a plurality of units, the unit being formed by one or more walls forming a closed cross section. The plurality of units include an outer portion and an inner portion, the outer portion being closer to the outer panel and the inner portion being closer to the inner panel. The inner portion includes an upper inner unit and a lower inner unit, the upper inner unit being configured to contact the inner panel at a vertical position substantially above a battery of the vehicle, and the lower inner unit being configured to contact the inner panel at a vertical position substantially below the battery of the vehicle when the rocker is subjected to a lateral impact load. The inner portion includes a blank space between the upper inner unit and the lower inner unit).

[0019] According to this aspect, a reinforcement can be provided inside the rocker, comprising an inner portion, the inner portion facing the interior of the vehicle and comprising at least two "legs" for deflecting loads above and below the battery of an electric (fully or partially electric) vehicle. The remaining portion of the reinforcement facing the outside of the vehicle, referred to as the outer portion, is configured to compress during a lateral impact and thus absorb energy.

[0020] In this way, a sufficient amount of energy can be absorbed at a relatively low weight by deformation of the outer part of the reinforcement, and loads due to lateral impacts (e.g. lateral forces) can be offset from the vehicle battery by the reinforcement "legs". The lower legs can further help stabilize the deformation of the rocker reinforcement. Battery intrusion and damage can be minimized or at least reduced. Therefore, vehicle damage can be reduced, the need for battery and vehicle repairs can also be reduced, and passenger safety can be increased. Since the empty space vertically separates the upper and lower "legs" of the reinforcement, the weight of the reinforcement can be kept fairly low.

[0021] Throughout this disclosure, a cell structure may be understood as a plurality of interconnected cells. Adjacent cells may share a wall or wall portion between them. The walls of the cells may be substantially straight, although in some embodiments, one or more cell walls may be curved. The cells form a channel along the longitudinal direction of the reinforcement, and thus along the longitudinal direction of the rocker arm.

[0022] In some embodiments, the outer portion of the cell structure may include at least one cell having a hexagonal cross-section. The outer portion may include, for example, a honeycomb structure. The cells of the hexagonal cross-section may help to enhance energy absorption. The cells of the outer portion may be oriented so that at least one cell wall of one or more cells is substantially parallel to the transverse direction in the cross-section. For example, a honeycomb outer portion and its cells are oriented so that one diagonal of a corresponding hexagonal cell in a cross-section connecting two opposite vertices of the cell is substantially parallel to the transverse direction, which may help to increase the energy absorbed by the outer portion of the rocker reinforcement.

[0023] In some embodiments, the upper internal unit is elongated and configured to deflect a lateral impact load, such as a portion of the lateral impact load, toward a floor of the vehicle (because the upper internal unit is elongated toward a floor of the vehicle when the rocker assembly is installed in the vehicle). In some of these embodiments, the unit structure may further include a top internal unit located above the upper internal unit, the upper internal unit being elongated and configured to deflect the impact load toward a seat cross member of the vehicle (because the top internal unit is elongated toward a seat cross member of the vehicle when the rocker assembly is installed in the vehicle). As a result, loads (e.g., forces) may be deflected toward a solid vehicle element rather than toward a battery box or battery, thereby reducing battery damage and increasing passenger safety.

[0024] In order to optimize the energy absorption and controlled deformation of the rocker reinforcement at a given weight, one or more of the following features may be used alone or in combination in some embodiments: the maximum length of the cross-section of the upper internal unit and the maximum length of the cross-section of the lower internal unit may be between one-third and two-thirds of the maximum width of the rocker reinforcement, for example between 40% and 60% of the maximum width of the rocker reinforcement, optionally approximately 50%; and the upper internal unit, the lower internal unit and one or more units vertically connecting the upper internal unit and the lower internal unit may form an arcuate cross-section.

[0025] In some embodiments, the average thickness of the lower inner unit and the upper inner unit can be higher than the average thickness of the outer portion of the rocker reinforcement. Similar to the above two features, such a thickness relationship can help increase energy absorption and effectively deflect side impact loads to the vehicle battery.

[0026] In some embodiments, at least a portion of the perimeter of the outer portion of the rocker reinforcement can follow the shape of the outer rocker panel in cross-section. An outer portion of the reinforcement having an outer portion shape that fits the shape of the outer rocker panel can help increase the energy absorbed in a collision while optimizing the space available within the rocker. A peripheral wall of the outer portion, such as a portion of the perimeter of the outer portion that is substantially parallel to the rocker outer panel, can also help support the rocker during a side impact, which can reduce rocker deformation and intrusion while still having high energy absorption. A peripheral cell wall along a portion of the outer rocker panel (i.e., a cell wall or wall portion that is part of the perimeter of the rocker reinforcement) provides a surface for withstanding impact from the outer rocker panel and can help provide stability to deformation during a side impact.

[0027] In some embodiments, the maximum width of the rocker in cross section may be 120 mm or greater. Such a rocker may be referred to as a "wide rocker". A wide rocker may particularly benefit from having a reinforcement as disclosed herein for optimizing the energy absorbed during a side impact while reducing the weight of the reinforcement and simultaneously reducing battery damage.

[0028] In some embodiments, the reinforcement may be an extruded profile, such as an aluminum alloy. In other embodiments, the profile may be formed by roll forming. Extrusion may be considered more suitable for profiles with closed cross-sections.

[0029] In some embodiments, the reinforcement is made of extruded aluminum. This can reduce the weight of the rocker reinforcement. In this article, aluminum can cover aluminum and its alloys. In particular, aluminum 6XXX and 7XXX ("6000" and "7000" series) can be used.

[0030] In some embodiments, the inner and outer panels of the rocker arm may be made of ultra-high strength steel, specifically press-hardened ultra-high strength steel, such as boron steel. The combination of lightweight aluminum for energy absorption and UHSS for strength may result in a good combination of energy absorption and impact resistance.

[0031] In a further aspect, an electric or hybrid vehicle is provided, comprising a rocker arm assembly according to any embodiment described herein.

[0032] In a further aspect, a method for manufacturing a rocker assembly for a vehicle is provided. The method includes: providing an inner rocker panel and an outer rocker panel; providing an aluminum rocker reinforcement having a cross-section according to any embodiment throughout the present disclosure; and mechanically attaching the rocker reinforcement to the inner rocker panel and the outer rocker panel so that when the rocker is subjected to a lateral impact load, the upper inner unit contacts the inner rocker panel at a vertical position generally above a battery of the vehicle, and the lower inner unit contacts the inner rocker panel at a vertical position generally below the battery of the vehicle.

[0033] The method can provide enhanced energy absorption while minimizing battery damage in a side impact and can also improve passenger safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Non-limiting embodiments of the present disclosure will be described hereinafter with reference to the accompanying drawings, in which:

[0035] Figure 1 A perspective view of an embodiment of a rocker arm assembly is schematically shown.

[0036] Figure 2 Schematically shows Figure 1 Cross section of a rocker arm assembly.

[0037] Figure 3 The schematic diagram shows the arrangement of the vehicle except for the bottom Figure 2 These embodiments of a cross section of a rocker arm assembly.

[0038] Figure 4 Schematically shows Figure 2 Embodiment of a cross section of a reinforcement after a side impact.

[0039] Figure 5 and Figure 6 Two embodiments of prior art rocker arm assemblies are schematically shown in cross-section.

[0040] Figure 7 A flow chart illustrating an embodiment of a method for manufacturing a rocker arm assembly is shown.

[0041] The drawings relate to example implementations and are intended only to aid in understanding the claimed subject matter and are not intended to limit the same in any sense. DETAILED DESCRIPTION

[0042] Figure 1 A rocker arm assembly 10 for a vehicle, such as an automobile, is schematically shown. A longitudinal direction 40, a vertical direction 41 and a transverse direction 42 as used throughout this disclosure and as defined above are depicted. These directions are substantially perpendicular to each other.

[0043] The rocker assembly 10 includes a rocker 20 and an elongated reinforcement 30 inside the rocker. The reinforcement 30 extends along a longitudinal direction 40 of the rocker 20. The rocker 20 includes an outer panel 11 and an inner panel 12, and the rocker reinforcement 30 is located between the inner panel 12 and the outer panel 11. When installed to a vehicle, the inner panel 12 of the rocker 20 will face the interior of the vehicle, while the outer panel 11 will face the exterior portion of the vehicle. That is, the outer panel 11 is configured to bear a lateral impact load, and the inner panel 12 is configured to transfer the lateral impact load to the internal structure of the vehicle.

[0044] The rocker arm 20 and the rocker arm reinforcement 30 have a length in a longitudinal direction 40 and a cross section substantially perpendicular to the longitudinal direction 40. The cross section is defined by a plane including two directions, namely a vertical direction 41 and a transverse direction 42 (or a plane parallel to these directions).

[0045] The longitudinal direction 40 of both the rocker arm 20 and the rocker arm reinforcement 30 also corresponds to the longitudinal direction of a vehicle to which the rocker arm 20 with the rocker arm reinforcement 30 may be mounted.

[0046] In some embodiments, the length of the rocker reinforcement 30 can be substantially equal to the length of the rocker 20. In some other embodiments, the length of the rocker reinforcement 30 can be less than the length of the rocker 20, for example, the reinforcement can have a length that is incorporated into at least 25%, or at least 50%, or at least 75% of the length of the rocker. The rocker 20 can include one or more rocker reinforcements 30.

[0047] The outer panel 11 and the inner panel 12 of the rocker arm 20 can be made of ultra-high strength steel (UHSS), in particular press-hardened ultra-high strength steel, such as boron steel. UHSS exhibits optimized maximum strength per unit weight and favorable formability properties. UHSS can exhibit an ultimate tensile strength of up to 1500MPa, or even 2000MPa or more, especially after a press-hardening operation. In such an operation, the steel billet is heated to above the austenitizing temperature, in particular above Ac3, so that the billet is substantially fully austenitized. After heating to above the temperature for a period of time, the billet is subjected to a pressing operation, in which the billet is deformed. At the same time, the billet is rapidly cooled so that the billet is substantially "fully hardened" and obtains a martensitic microstructure. Examples of hardened steels include UHSS, such as 22MnB5 steel or 1500, Commercially available from Arcelor Mittal. Another example of a hardenable boron steel is 37MnB5, or 2000.

[0048] The composition of 1500 is summarized in weight percentage as follows (the balance is iron (Fe) and impurities):

[0049] Maximum carbon (C) (%): 0.25

[0050] Maximum Silicon (Si) (%): 0.4

[0051] Maximum manganese (Mn) (%): 1.4

[0052] Maximum phosphorus (P) (%): 0.03

[0053] Maximum sulfur (S) (%): 0.01

[0054] Aluminum (Al) (%): 0.01-0.1

[0055] Maximum titanium (Ti) (%): 0.05

[0056] Maximum niobium (Nb) (%): 0.01

[0057] Maximum copper (Cu) (%): 0.20

[0058] Maximum boron (B) (%): 0.005

[0059] Maximum chromium (Cr) (%): 0.35

[0060] 1500 may have, for example, a yield strength of 1100 MPa and an ultimate tensile strength of 1500 MPa.

[0061] 2000 is another boron steel with even higher strength. The yield strength of 2000 may be 1400 MPa or higher, and the ultimate tensile strength may be higher than 1800 MPa. The composition of 2000 is summarized in weight percentage as follows (the balance is iron (Fe) and impurities):

[0062] Maximum carbon (C) (%): 0.36

[0063] Maximum Silicon (Si) (%): 0.8

[0064] Maximum manganese (Mn) (%): 0.8

[0065] Maximum phosphorus (P) (%): 0.03

[0066] Maximum sulfur (S) (%): 0.01

[0067] Aluminum (Al) (%): 0.01-0.06

[0068] Maximum titanium (Ti) (%): 0.07

[0069] Maximum niobium (Nb) (%): 0.07

[0070] Maximum copper (Cu) (%): 0.20

[0071] Maximum boron (B) (%): 0.005

[0072] Maximum chromium (Cr) (%): 0.50

[0073] Maximum Molybdenum (Mb) (%): 0.50

[0074] The outer panel 11 and the inner panel 12 may include mounting flanges 13 on their lower and upper portions for attaching the panels to each other and also to other components of the vehicle frame.

[0075] In some embodiments, the reinforcement 30 may be made of an extruded profile, such as an aluminum alloy. Extruded profiles are particularly suitable when a long reinforcement is required. In other embodiments, the rocker reinforcement may be roll formed. Suitable aluminum alloys include aluminum 6000 series or aluminum 7000 series. Suitable aluminum alloys include, for example, 6005, 6060, 6061, 6063, 6082, and 6106.

[0076] The use of aluminum can reduce the weight of the rocker reinforcement 30, and thus reduce the weight of the rocker assembly 10 and the weight of the vehicle to which the rocker assembly can be mounted. The use of aluminum also facilitates obtaining a similar Figure 2 and 3 The cross-section of the rocker reinforcement 30 is shown in FIG. The thickness and shape of the cross-section of the rocker reinforcement 30 can also be more easily adjusted by using aluminum and extrusion. Likewise, the length of the extruded rocker reinforcement 30 can be easily customized. In some embodiments, the length of the rocker reinforcement 30 can be between 1 and 1.5 meters. The length of the rocker reinforcement can vary specifically as a function of the length of the rocker, but the geometry and space available inside the rocker can also play a role.

[0077] The combination of lightweight aluminum for energy absorption and UHSS for strength can result in a good combination of energy absorption and impact resistance.

[0078] Figure 2 Schematically shows Figure 1 The rocker arm reinforcement 30 is defined as a cross-section of the rocker arm assembly 10. The rocker arm reinforcement 30 is made of a unit structure perpendicular to the longitudinal direction 40 of the rocker arm 20 along at least a portion of the rocker arm 20. The unit structure includes a plurality of units, and the unit is formed by one or more walls forming a closed cross section. That is, each unit is formed by one or more walls forming a closed cross section.

[0079] The plurality of cells, and thus the rocker reinforcement, include an inner portion 32 and an outer portion 31. The inner portion 32 includes an upper inner cell 34, the upper inner cell 34 being configured to contact the inner rocker panel 12 at a vertical position substantially above the battery of the vehicle when the rocker is subjected to a lateral impact load. The inner portion 32 also includes a lower inner cell 33, the lower inner cell 33 being configured to contact the inner rocker panel 12 at a vertical position substantially below the battery of the vehicle. The inner portion 32 includes a blank space 25 between the upper inner cell 34 and the lower inner cell 33. The blank space 25 may be, for example, a vertical gap separating the upper inner cell 34 and the lower inner cell 33.

[0080] exist Figure 2 In the embodiment of FIG. 4 , a lateral impact will come from the right hand side of the figure. Since the "legs", i.e., the upper inner unit 34 and the lower inner unit 33, are configured to direct the lateral forces that compress the rocker arm above and below the battery box 46, damage to the battery box and the battery can be reduced. Intrusion of the rocker arm assembly into the battery box can be avoided or at least reduced. Contact between the battery box and the rocker arm can also be avoided or at least reduced.

[0081] In some embodiments, for example, Figure 1-3 In the embodiment of the present invention, the lower internal unit 33 is a bottom internal unit 33. In other embodiments not shown, there may be one or more units below the lower internal unit 33. Similarly, in some embodiments, the upper internal unit 34 may be a top internal unit 34 ( Figure 1-3 not shown).

[0082] The inner portion 32 of the unit structure is closer to the inner rocker panel 12 than the outer portion 31. Therefore, the outer portion 31 is closer to the outer rocker panel 11 than the inner portion 32.

[0083] The outer portion 31 of the cell structure may include at least one cell having a hexagonal cross section. Figure 2 In an embodiment, a unit including a regular hexagonal cross-section is shown. In other embodiments, the outer portion 31 may include a plurality of units, including all units of the outer portion 31, which are regular hexagons in cross-section. The unit including a regular hexagon may include walls having substantially the same length and a central angle of approximately 120° in cross-section. In other embodiments, one or more units of the outer portion 31 may be an irregular hexagon. An irregular hexagon may be understood as a hexagon in which at least one of the following two conditions occurs: not all central angles are approximately 120°, and not all walls have the same length. Using a regular hexagon in cross-section may increase the energy absorbed by the rocker reinforcement 30 compared to when the cross-section of the hexagonal unit is irregular.

[0084] In some embodiments, the outer portion 31 may include, for example, a honeycomb structure. Relative to other configurations of the outer portion 31, such as the cross-sectional shape of the cells, the honeycomb outer portion may increase the amount of energy absorbed in a side impact. Figure 1-3 The outer portion 31 of the reinforcement member 30 can be considered as a honeycomb structure. In other embodiments, the outer portion of the honeycomb body can include more Figure 1-3 The honeycomb outer portion 31 may include more or fewer cells. The honeycomb outer portion 31 may include regular and / or irregular hexagons.

[0085] In some embodiments, the cells of the outer portion 31 can be oriented so that at least one wall (e.g., two opposing walls) of one or more cells therein is substantially parallel to the transverse direction 42 in cross section. That is, the top wall and / or the bottom wall of one or more cells of the outer portion 31 can extend along the transverse direction 42 in cross section. This can be achieved in Figure 1-3 This particular orientation of the cells may be particularly suitable for absorbing energy in lateral impacts in which a force or at least a component of a force is applied substantially in the transverse direction 42. Such an orientation may also increase the energy absorption in transverse impacts relative to a case in which, for example, two opposite walls of a cell of the outer portion 31 are aligned in a cross section along the vertical direction 41 or along another direction different from the transverse direction 42.

[0086] In this or other embodiments, the rocker reinforcement 30 may include a cell structure, particularly an outer portion 31 of the cell structure, such that in cross section, at least one wall, such as two opposing walls, of one or more cells are substantially aligned along a vertical direction 41. In these embodiments, the walls of the cells extending along the vertical direction 41 in cross section may be referred to as vertical side walls.

[0087] Still in either of the two aforementioned embodiments, or in other embodiments, at least one wall of one or more cells of the outer portion 31 of the cell structure, and at least one wall of the entire cell structure as a whole, may be substantially parallel in cross-section to a direction different from the lateral direction 42 and the vertical direction 41.

[0088] Figure 3 The schematic diagram shows the arrangement outside the vehicle bottom. Figure 2 1. In this embodiment, the upper inner unit 34 is elongated and configured to deflect lateral impact loads toward the floor 47 of the electric vehicle. In some embodiments, the vehicle floor 47 can be made of hot stamped boron steel. The arrow on the upper inner unit 34 shows Figure 3Thus, damage to the battery and / or battery box can be avoided or at least reduced because the impact is offset above the battery 46 towards a rigid and / or solid element, such as the vehicle floor 47. In some embodiments, the battery box may include a box made of steel sheet. The battery cells, i.e., the batteries, may be placed inside the box. The battery box may include a cooling system, electrical connections, busbars, etc. A reinforcement frame may be arranged around the battery box.

[0089] Although not shown in the example of the drawings, in other embodiments, the upper inner unit 34 can be elongated and configured to deflect the lateral impact load toward the seat cross member 48 of the vehicle. The seat cross member 48 is also a resisting element, which can withstand the load of the lateral impact. In this case as well, when the load is transferred to the seat cross member 48, damage to the battery 46 can be minimized. In some embodiments, the seat cross member 48 can be a separate component from the vehicle floor 47. In other embodiments, the seat cross member can be integrated into the vehicle floor 47. The seat cross member can be made, for example, by hot stamping boron steel.

[0090] In embodiments where the upper inner unit 34 is configured to deflect lateral impact loads toward the vehicle floor 47, the unit structure may further include a top inner unit 35 above the upper inner unit 34, the top inner unit configured to deflect the impact load toward a set cross member 48 of the vehicle. When the rocker assembly 10 is installed in the vehicle, the top inner unit 35 may be extended toward the seat cross member. The specific configuration may further enhance impact deflection away from the battery (box) 46 and energy absorption by other vehicle elements (floor, seat cross member) that are stronger than the battery box.

[0091] In some embodiments, the maximum length of the cross section 37 of the upper inner cell 34 and the maximum length of the cross section 36 of the lower inner cell 33 (and optionally, the maximum length of the cross section of the top inner cell 35) can be between one-third and two-thirds of the maximum width of the rocker reinforcement, such as between 40% and 60%, such as about 50%. Such a ratio can help the reinforcement "legs" deform less than the outer portion 31 of the reinforcement 30, and thus provide a proper and optimized balance between absorbing a large amount of energy by the outer portion 31 of the reinforcement 30 and diverting a large amount of unabsorbed energy away from the battery 46.

[0092] The upper internal unit, the lower internal unit and one or more units vertically connecting the upper 34 and lower 33 internal units may form an arc-shaped cross section. Figure 1-3In the example of FIG. 1 , the cell groups have a revolved C-shape. The empty space 25 between the upper and lower inner cells, such as a D-shaped gap, can help reduce the weight of the reinforcement without compromising energy absorption. The arcuate shape of the upper inner cell 34, the lower inner cell 33, and the connecting cell 39 can help promote the transfer of energy away from the vehicle battery. In other embodiments, other shapes of the gaps and corresponding cells 33, 34, 39 are also possible.

[0093] The cross-sectional width of the rocker reinforcement 30, where the curvature of the camber is greatest, i.e., if the perimeter of the rocker reinforcement forms a camber in the area between the upper inner cell 34 and the lower inner cell 33, for example, around a C-shaped turn at the height where the curvature of the camber is greatest; can be between one-third and two-thirds of the maximum width of the rocker reinforcement. For example, such a cross-sectional width of the rocker reinforcement can be between 40% and 60%, such as approximately 50%, of the maximum width of the rocker reinforcement 30. This can again help the inner portion 32 deflect lateral impact loads from under and over the battery box 46, while the outer portion 31 of the rocker reinforcement 30 can collapse and absorb a considerable amount of energy.

[0094] In addition to the shape and length and / or width of the "legs" 33, 34, 35 and outer portion 31 of the reinforcement 30, the thickness of the various cells of the reinforcement 30 may also be tailored to adjust for compression and / or deflection of an impact experienced by the outer rocker panel 11. The thickness of the walls of the cell structure of the reinforcement 30, and particularly the thickness of the walls of the outer portion 31, may be varied to optimize the amount of energy absorbed by the rocker assembly 10 in a lateral impact. The thickness of the various walls of the "legs" may similarly be varied to accommodate the direction in which the impact load deflects the cell 46.

[0095] In some embodiments, the average thickness of the cell walls of the rocker reinforcement 30 may vary between 1.5 and 6 mm, for example between 2 and 4 mm. In some embodiments, all walls of the cells of the outer portion 31 of the reinforcement 30 may have substantially the same thickness. In other embodiments, the walls of the cells of the outer portion 31 of the reinforcement 30 may have different thicknesses from each other. For example, the thickness of the cell walls of the outer portion 31 may vary between 1.5 mm and 5 mm. That is, for example, one or more cell walls may have a thickness of 3.2 mm. These thicknesses, particularly for extruded aluminum rocker reinforcements, may give the reinforcement sufficient strength while maximizing energy absorption for a given weight.

[0096] In some embodiments, the average (i.e., mean) thickness of the rocker reinforcement "legs" (e.g., the lower inner cell 33 and the upper inner cell 34) can be higher than the average thickness of the outer portion 31 of the rocker reinforcement 30. This can help the outer portion 31 collapse primarily during a side impact, while the "legs" do not collapse as much and may divert loads, such as forces, away from the vehicle battery 46. Figure 4 An example of this is shown in .

[0097] Figure 4 Schematically shows after a side impact from the right hand side of the image Figure 2 The outer portion 31 of the rocker reinforcement 30 has been fully compressed, while the "legs" 33, 34, 35 have been deformed, but are smaller than the outer portion 31 of the rocker reinforcement 30. Figure 4 It can also be seen how the lower inner unit 33 and the upper inner unit 34 respectively maintain a vertical gap between them, thereby avoiding or limiting the transfer of loads to the battery (tray) arranged inside the rocker arm.

[0098] In some embodiments, at least a portion of the outer edge (i.e., the perimeter) of the outer portion 31 of the rocker reinforcement 30 may follow the shape of the outer rocker panel 11 in cross section. For example, the top and side portions of the perimeter of the outer portion 31 follow the shape of the outer rocker panel 11 in cross section. Figure 2 and 3 If the perimeter of the outer portion 31 configured to withstand the impact of the outer panel 11 of the rocker 20 in a side impact follows the shape of the outer rocker panel 11, more efficient use of the space inside the rocker and enhanced energy absorption can be achieved. In some embodiments, the sides of the perimeter of the outer portion 31 can be substantially parallel to the outer rocker panel 11 in cross section. This can be achieved, for example, in Figure 2 and Figure 3 See the examples in the examples.

[0099] In some embodiments, the maximum width 38 of the rocker arm 20 in the cross section may be 120 mm or greater. Such a rocker arm may be referred to as a "wide rocker arm". Due to the cross-sectional dimensions of the wide rocker arm, the wide rocker arm may not be fully compressed during a lateral impact. That is, only a portion of the rocker arm closest to the lateral impact may experience deformation and thus absorb energy. Providing a rocker arm reinforcement 30 as described herein in a "wide rocker arm" may be particularly helpful because the outer portion 31 of the reinforcement will be arranged in the rocker arm portion that is mainly subjected to compression, while the inner portion 32 having the "legs" 33, 34, 35 will be arranged in the rocker arm portion that may not be compressed or may be less compressed. The outer portion 31 can help to enhance the energy absorbed, while preventing or reducing damage to the battery 46 caused by the force of the "legs" 33, 34, 35 offsetting the battery, and all of this will not add unnecessary mass and weight to the inner portion 32. An optimized and effective rocker arm assembly 10 can be obtained.

[0100] The maximum width of the rocker reinforcement 30 may be similar to but less than the maximum width of the rocker 20. In some embodiments, the reinforcement 30 may contact the surface of the inner and / or outer panels of the rocker panel at least at some areas along the longitudinal direction 40.

[0101] The rocker arm 20 and the rocker arm reinforcement 30 may be attached to each other by one or more fasteners 14. Figure 2 In the embodiment, the fastener 14 includes two strips, such as steel strips. The steel strips may be made of high-strength steel, in particular high-strength low-alloy steel. In one embodiment, HSLA420 commercialized by ArcelorMittal may be used. Similar steels may include 420LA. The "420" used in these examples indicates the minimum yield strength of the steel. Alternative steels may also be used.

[0102] One end of the strap may be connected to the mounting flange 13 of the outer rocker panel 11 and / or the inner rocker panel 12. The other end may be connected to the reinforcement 30, for example, to the bottom or top of the reinforcement. Figure 2 The embodiment shown in FIG. 1 shows a top strap connected to the top of the reinforcement 30 and a bottom strap connected to the bottom of the reinforcement 30. In some embodiments, the strap 14 may be attached to the reinforcement and / or mounting flange 13 by screws or rivets. This type of fastener may be particularly suitable for connecting the center portion of the rocker reinforcement 30 to the rocker 20, but it may also be used to attach one or both longitudinal ends of the reinforcement 30 to the rocker 20.

[0103] Another possible way of attaching the reinforcement 30 and the rocker 20, in particular the longitudinal ends of the reinforcement 30, may be by connecting the ends of a strip, such as a steel strip, to the inner portion of the inner rocker panel 12 or the outer rocker panel 11 and connecting the other ends of the strip to the longitudinal ends of the reinforcement. Thus, the strip may extend along the longitudinal direction 40.

[0104] The fastener 14 may include any suitable connecting element. The fastener 14 may include at least one or more of a strip, a bracket, a rivet, a screw, a bolt, an adhesive, and a resin. The use of adhesives and resins may reduce vibration.

[0105] According to the rocker arm assembly of the present invention (for example Figure 2 The performance of the rocker arm assembly 10) has been compared in a simplified subsystem with the performance of several rocker arm assemblies of the prior art in the Euro NCAP test. In the comparison case, all reinforcements were made of extruded aluminum. Figure 5 and Figure 6 Two embodiments of the prior art are shown in FIG. Figure 6 The Volvo XC60 in Figure 7 The Jaguar Land Rover Discovery Sport in the . These embodiments of the rocker arm assembly of the prior art and Figure 2 The energy absorbed by the unit cross-sectional mass of the rocker arm assembly of the rocker arm assembly (abbreviated herein as AE / SM). The cross-sectional mass (SM) represents the weight of the rocker arm assembly 10 / the length of the cross-sectional (longitudinal portion) of the rocker arm assembly. It is usually expressed in kilograms / meter of cross-sectional area. The length is measured along the longitudinal direction 40. The energy absorbed by the aluminum reinforcement / the cross-sectional mass of the aluminum reinforcement (abbreviated herein as AE(Al) / SM(Al)) is also shown in the table.

[0106]

[0107]

[0108] Table 1

[0109] As can be seen in Table 1, rocker reinforcements and rocker assemblies according to embodiments of the present disclosure may result in increased energy absorption relative to prior art rocker assemblies and rocker reinforcements.

[0110] Figure 7 A flow chart is shown of a method 100 for manufacturing a rocker assembly 10 for a vehicle including a rocker 20 and a rocker reinforcement 30 attached to the rocker 20. The rocker 20 and the rocker reinforcement 30 may be any of the rockers 20 and rocker reinforcements 30 described throughout the disclosure.

[0111] At block 105, the method 100 includes providing an outer rocker panel 11 and an inner rocker panel 12. The inner and outer rocker panels may be made of hardened steel, such as UHSS.

[0112] The method 100 further includes, at block 110, providing a rocker reinforcement, such as an aluminum rocker reinforcement 30, having a cross-section according to any embodiment disclosed herein, such as Figure 2 and 3 In some embodiments, extrusion can be used to obtain the rocker reinforcement 30.

[0113] In order to obtain an aluminum rocker reinforcement 30 having a cross-section as disclosed herein by extrusion, a die having a cross-sectional profile as disclosed herein may first be obtained. The die may be made of steel. The die may be preheated to a temperature between 400-600° C. to facilitate uniform flow of aluminum through the die. Once the die is loaded in the extruder, the aluminum billet (which may be preheated to make it ductile, for example to a temperature between 400-600° C.) may be pushed against and through the die by a push rod. The aluminum extrusion may have a desired cross-section. Cooling, alignment and / or cutting of the aluminum extrusion may additionally be performed in order to obtain the rocker reinforcement 30.

[0114] The method 100 also includes, at frame 115, mechanically attaching the rocker reinforcement 30 to the inner rocker panel 12 and the outer rocker panel 11 such that when the rocker is subjected to a lateral impact load, the upper inner unit contacts the inner rocker panel at a vertical position generally above a battery of the vehicle, and the lower inner unit contacts the inner rocker panel at a vertical position generally below the battery of the vehicle.

[0115] As described above, the rocker reinforcement 30 may be attached to the outer rocker panel 11 and / or the inner rocker panel 12. To this end, a fastener 14 such as a steel band may be used. For example, two or more steel bands may be used. The outer rocker panel and the inner rocker panel may also be connected to each other by fasteners.

[0116] "Soft zones", i.e., areas of lower mechanical strength (areas having lower ultimate tensile strength and yield strength, but possibly higher ductility), may be provided at certain areas of the rocker arm 20 that are envisioned as connection points. For example, soft zones may be provided at areas of the rocker arm panel to which screws, rivets, or similar fasteners may be attached. This may facilitate the connection between the rocker arm 20 and the rocker arm reinforcement 30, for example, where the rocker arm 20 is made of UHSS and the reinforcement 30 is made of aluminum. Providing soft zones at the connection points of the rocker arm may also help avoid, or at least reduce, stress concentrations at these points, and possible early cracking or rupture in the event of an impact.

[0117] Soft zones may additionally or alternatively be provided in one or both rocker panels 11 , 12 to improve the ductility and energy absorption of the rocker panel in the areas where these soft zones are created.

[0118] Soft zones can be produced, for example, by partial heat treatment after hot forming press quenching. Lasers or induction heaters can be used to locally produce areas of different microstructures on the rocker panel.

[0119] In some embodiments, the mounting flange 13 of the rocker arm 20 can be formed as a soft area in the press-hardened ultra-high strength steel. If the flange 13 is made as a softer area than the rest of the rocker arm 20, the flanges 13 can be more easily connected to each other and to the fasteners 14. Stress concentrations at the connection points can be avoided or at least reduced.

[0120] Although only a plurality of embodiments are disclosed herein, other replacements, modifications, uses and / or their equivalents are possible. In addition, all possible combinations of the described embodiments are also contemplated. Therefore, the scope of the present disclosure should not be limited to the specific embodiments, but should only be determined by a reasonable reading of the appended claims.

Claims

1. A rocker arm assembly (10) for a vehicle, wherein include: A rocker arm (20) comprising an outer panel (11) configured to bear a lateral impact load and an inner panel (12) configured to transfer the lateral impact load to an inner structure of a vehicle, and a rocker reinforcement (30) in the rocker (20) between the inner panel (12) and the outer panel (11), the rocker reinforcement (30) extending along a longitudinal direction (40) of the rocker (20) and defining a unit structure along at least a portion of the rocker in a cross section perpendicular to the longitudinal direction (40) of the rocker (20), wherein the cell structure comprises a plurality of cells, the cells being formed by one or more walls forming a closed cross section, and wherein the plurality of cells comprises an outer portion (31) and an inner portion (32), the outer portion (31) being closer to the outer panel (11) and the inner portion (32) being closer to the inner panel (12), wherein the inner portion (32) includes an upper inner unit (34) and a lower inner unit (33), the upper inner unit being configured to contact the inner panel (12) at a vertical position substantially above a battery (46) of the vehicle, and the lower inner unit being configured to contact the inner panel (12) at the vertical position substantially below the battery (46) of the vehicle when the rocker arm is subjected to the lateral impact load, and The inner portion (32) includes a blank space (25) between the upper inner unit (34) and the lower inner unit (33).

2. The rocker arm assembly according to claim 1, in, The outer portion (31) comprises at least one unit having a hexagonal cross section.

3. The rocker arm assembly according to claim 2, in, The outer portion (31) comprises a honeycomb structure.

4. A rocker arm assembly according to any one of the preceding claims, in, The cells of the outer part (31) are oriented so that at least one wall of one or more cells is substantially parallel to a transverse direction (42) of the rocker arm (20) in cross section, wherein the transverse direction (42) is perpendicular to the longitudinal direction (40) and the vertical direction (41) of the rocker arm (20).

5. A rocker arm assembly according to any one of the preceding claims, in, The upper interior unit (34) is elongated and configured to deflect the side impact load toward a floor (47) of the vehicle.

6. The rocker arm assembly according to claim 5, in, The unit structure also includes an upper interior unit (35) located above the upper interior unit (34), the upper interior unit (35) being elongated and configured to deflect impact loads toward a seat cross member (48) of the vehicle.

7. A rocker arm assembly according to any one of the preceding claims, in, The maximum length of the cross section (37) of the upper inner unit (34) and the maximum length of the cross section (36) of the lower inner unit (33) are between one third and two thirds of the maximum width of the rocker reinforcement (38).

8. A rocker arm assembly according to any one of the preceding claims, in, The upper internal unit (34), the lower internal unit (33) and one or more units (39) vertically connecting the upper internal unit (34) and the lower internal unit (33) form an arc-shaped cross-section.

9. A rocker arm assembly according to any one of the preceding claims, in, The average thickness of the lower inner cell (33) and the upper inner cell (34) is greater than the average thickness of the outer portion (31) of the rocker reinforcement (30).

10. A rocker arm assembly according to any one of the preceding claims, in, At least a portion of the periphery of the outer portion (31) of the rocker reinforcement (30) follows the shape of the outer panel (11) of the rocker in cross section.

11. A rocker arm assembly according to any one of the preceding claims, in, The maximum width (38) of the rocker arm (20) in cross section is 120 mm or greater.

12. A rocker arm assembly according to any one of the preceding claims, in, The reinforcement (30) is made of an extruded profile, and optionally made of an extruded aluminum alloy profile.

13. A rocker arm assembly according to any one of the preceding claims, in, The inner panel (12) and the outer panel (11) of the rocker arm (20) are made of ultra-high strength steel.

14. A method (100) for manufacturing a rocker arm assembly (10) for a vehicle according to any one of the preceding claims, the method include: Providing (105) an inner rocker panel (12) and an outer rocker panel (11); Providing (110) an aluminum rocker reinforcement (30) having a cross-section according to any one of the preceding claims; and The rocker reinforcement (30) is mechanically attached (115) to the inner rocker panel (12) and the outer rocker panel (11) so that when the rocker (20) is subjected to a lateral impact load, the upper inner cell (34) contacts the inner rocker panel (12) at a vertical position generally above a battery (34) of the vehicle, and the lower inner cell (33) contacts the inner rocker panel (12) at a vertical position generally below the battery of the vehicle.

15. The method according to claim 14, in, Two or more steel straps (14) are used to attach (115) the rocker reinforcement (30) and the rocker (20).

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