Patent Description:
Roll-forming is a conventional method for forming elements to obtain a specific shape as seen in cross-section. Many of these roll-formed elements are beams and elongated structures that are used in a variety of structures, for instance as crash barriers along roads and as bumpers in vehicles. In general, a bumper beam for vehicles may be rolled to a closed form as seen in cross-section. Since there are regulations in many countries regarding what type of impact and how high impact these beams are supposed to handle, different conventional solutions have been developed to handle the crash forces. <CIT> discloses a bumper beam of a sheet metal formed to a closed hollow structure.

The inventors of the present invention have found drawbacks in conventional bumper beams. For example, some conventional bumper beams are not sufficiently strong or resistant while still having a sufficiently low weight.

An object of embodiments of the invention is to provide a solution which mitigates or solves drawbacks and problems of conventional solutions.

The above and further objects are solved by the subject matter of the independent claim. Further advantageous embodiments of the invention can be found in the dependent claims.

According to a first aspect of the invention, the above mentioned and other objects are achieved with a bumper beam of a sheet metal formed to a closed hollow structure comprising a first side wall and a second side wall,.

An advantage of the bumper beam according to the first aspect is that an improved bumper beam is provided. An advantage of the bumper beam according to the first aspect is that an improved impact protection for a vehicle having the innovative bumper beam is provided. An advantage of the bumper beam according to the first aspect is that an advantageous deformation of the bumper beam for absorbing impacts or impact energy is provided while maintaining or improving the rigidity and reinforcement of the bumper beam in order to prevent or counteract penetration by external objects upon a collision. An advantage of the bumper beam according to the first aspect is that an efficient energy absorption of energy of an impact, for example upon a collision, is provided. An advantage of the bumper beam according to the first aspect is that the performance of the bumper beam in collisions is improved, for example because the bumper beam can be deformed in a more controlled and more predicted manner in relation to conventional solutions.

An advantage of the bumper beam according to the first aspect is that the weight and thus the cost of the bumper beam can be reduced while still maintaining or even improving the rigidity and reinforcement of the bumper beam. An advantage of the bumper beam according to the first aspect is that the horizontal member will have a reinforcing effect on the bumper beam during deformation without the need of excessive welding and/or without the need for the first longitudinal side to be welded. Less weld results in a reduced weight of the bumper beam. Less welding facilitates the production of the bumper beam. Upon an impact, the recess locks the horizontal member and prevents the horizontal member from sliding along an inner surface of the hollow structure during the impact.

According to an advantageous embodiment of the bumper beam according to the first aspect, the closed hollow structure together with the first and second side walls define an inner space, wherein in the inner space the first longitudinal side is unwelded to the second side wall. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved.

According to a further advantageous embodiment of the bumper beam according to the first aspect, a wall portion of the second side wall defines the recess, wherein in one or more of the recess and inner space the first longitudinal side is unwelded to the wall portion. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved.

According to another advantageous embodiment of the bumper beam according to the first aspect, in the recess the first longitudinal side is unattached to one or more of the second side wall and wall portion. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved.

According to yet another advantageous embodiment of the bumper beam according to the first aspect, in the inner space the first longitudinal side is unattached to one or more of the second side wall and wall portion. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved.

According to still another advantageous embodiment of the bumper beam according to the first aspect, the sheet metal is bent to form the horizontal member, wherein the second longitudinal side ends just below the region of the bent forming the horizontal member. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved.

According to an advantageous embodiment of the bumper beam according to the first aspect, when the bumper beam is attached to a main body of a vehicle, one or more of the horizontal member and first longitudinal side is/are configured to point at least in a direction toward the main body of the vehicle. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved. The main body of the vehicle may comprise a main frame or a chassis. However, for alternative embodiments, one or more of the horizontal member and first longitudinal side may be configured to point in a direction away from the main body of the vehicle.

According to a further advantageous embodiment of the bumper beam according to the first aspect, when the bumper beam is attached to a main body of a vehicle, the recess is configured to open in a direction away from the main body of the vehicle. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved. However, for alternative embodiments, the recess may be configured to open in a direction toward the main body of the vehicle.

According to another advantageous embodiment of the bumper beam according to the first aspect, when the bumper beam is attached to a main body of a vehicle, one or more of the horizontal member and first longitudinal side is/are configured to extend into the recess at least in a direction toward the main body of the vehicle. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved.

According to yet another advantageous embodiment of the bumper beam according to the first aspect, the closed hollow structure has an outer side and an inner side, wherein the outer side faces away from the horizontal member, and wherein the second longitudinal side is welded to the outer side of the closed hollow structure. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved.

According to still another advantageous embodiment of the bumper beam according to the first aspect, the first longitudinal side has a longitudinal edge, wherein in the recess there is a gap or distance between the longitudinal edge of the first longitudinal side and the second side wall at least before any deformed due to an impact. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved. An advantage of this embodiment is that before any impact, any contact between the first longitudinal side and the surface defining the recess is avoided, which otherwise could lead to noise due to vibrating contact between the horizontal member and the surface of the recess, when the bumper beam is attached to a vehicle. An advantage of this embodiment is that before any impact, corrosion issues may be avoided since water entering the bumper beam will not be gathered on the horizontal member due to the gap. However, for alternative embodiments, in the recess there may be a physical contact between the longitudinal edge of the first longitudinal side and the second side wall before any deformed due to an impact.

According to an advantageous embodiment of the bumper beam according to the first aspect, the first longitudinal side has a longitudinal edge, wherein the horizontal member extends into, but with a gap or distance between the longitudinal edge of the first longitudinal side and the recess when the bumper beam is manufactured. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved. An advantage of this embodiment is that before any impact, any contact between the first longitudinal side and the surface defining the recess is avoided, which otherwise could lead to noise due to vibrating contact between the horizontal member and the surface of the recess, when the bumper beam is attached to a vehicle. An advantage of this embodiment is that before any impact, corrosion issues may be avoided since water entering the bumper beam will not be gathered on the horizontal member due to the gap.

According to a further advantageous embodiment of the bumper beam according to the first aspect, the gap or distance is between a few millimetres and the depth of the recess. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved.

According to another advantageous embodiment of the bumper beam according to the first aspect, the second longitudinal side ends in a region of the horizontal member. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved.

According to still another advantageous embodiment of the bumper beam according to the first aspect, the recess opens toward the horizontal member. An advantage of this embodiment is that the impact protection and/or the bumper beam is/are further improved.

The above-mentioned features and embodiments of the bumper beam may be combined in various possible ways providing further advantageous embodiments.

Further advantageous embodiments of the bumper beam according to the present invention and further advantages with the embodiments of the present invention emerge from the detailed description of embodiments.

Embodiments of the invention will now be illustrated, for exemplary purposes, in more detail by way of embodiments and with reference to the enclosed drawings, where similar references are used for similar parts, in which:.

With reference to <FIG>, aspects of an embodiment of the bumper beam <NUM> according to the first aspect of the invention are schematically illustrated. The bumper beam <NUM> may be described to be elongated. The bumper beam <NUM> may be described to have a longitudinal extension, for example, extending in a longitudinal direction. The bumper beam <NUM> may be configured for the attachment to a vehicle, for example, for the attachment to a main body <NUM> of a vehicle. The main body <NUM> may comprise a main frame or a chassis.

With reference to <FIG>, the bumper beam <NUM> is made of a sheet metal, or a sheet metal plate. The sheet metal is formed to a closed hollow structure <NUM>. The closed hollow structure <NUM> includes a first side wall <NUM> and a second side wall <NUM>. The sheet metal includes, or forms, a first longitudinal side <NUM> and a second longitudinal side <NUM>. The first longitudinal side <NUM> may be described to be opposite the second longitudinal side <NUM>, for example before the sheet metal is formed to the closed hollow structure <NUM>. The sheet metal is formed such that the first longitudinal side <NUM> is formed to a horizontal member <NUM> located inside the closed hollow structure <NUM> and such that the second side wall <NUM> forms a recess <NUM> into which the first longitudinal side <NUM> extends. When the bumper beam <NUM> is attached to the main body <NUM> of a vehicle, "horizontal" with regard to the horizontal member <NUM> is to be understood as substantially horizontal. The extension of the horizontal member <NUM> may deviate from a strictly horizontal orientation, for example when the vehicle is resting on a slope. For some embodiments, the horizontal member <NUM> may be referred to as a horizontal element or web.

With reference to <FIG>, the first longitudinal side <NUM> and the recess <NUM> are configured to form a locking of the horizontal member <NUM>, or a locking action, when the bumper beam <NUM> is deformed due to an impact. In the recess <NUM>, the first longitudinal side <NUM> is unwelded, i.e. not welded, to the second side wall <NUM> while the second longitudinal side <NUM> is welded to the closed hollow structure <NUM>. It may be defined, or described, that the first longitudinal side <NUM> and the recess <NUM> are configured cooperate, or interact, to form the locking of the horizontal member <NUM> when the bumper beam <NUM> is deformed due to an impact.

With reference to <FIG>, the bumper beam <NUM> may be used as a front bumper beam, i.e. positioned at the front of the main body <NUM> of the vehicle, or may be used as a rear bumper beam, i.e. positioned at the rear end of the main body <NUM> of the vehicle. The sheet metal and/or the closed hollow structure <NUM> may be made of a material comprising or consisting of a metal or a metal alloy. However, other materials are possible. The closed hollow structure <NUM> may be described to have a longitudinal extension, for example, extending in a longitudinal direction. When attached to the main body <NUM> of a vehicle, the longitudinal extension of the bumper beam <NUM> or of the closed hollow structure <NUM> may extend in a longitudinal direction which is transverse to the longitudinal extension of the main body <NUM> of the vehicle.

With reference to <FIG>, for some embodiments, the closed hollow structure <NUM> together with the first and second side walls <NUM>, <NUM> may define an inner space <NUM>. In the inner space <NUM>, the first longitudinal side <NUM> may be unwelded to the second side wall <NUM>. For some embodiments, the second side wall <NUM> may comprise a wall portion <NUM>. The wall portion <NUM> of the second side wall <NUM> may define, or form, the recess <NUM>. In the recess <NUM> and/or in the inner space <NUM>, the first longitudinal side <NUM> may be unwelded to the wall portion <NUM>.

With reference to <FIG>, for some embodiments, in the recess <NUM>, the first longitudinal side <NUM> is unattached to the second side wall <NUM> and/or the wall portion <NUM>. For some embodiments, in the inner space <NUM>, the first longitudinal side <NUM> is unattached to the second side wall <NUM> and/or the wall portion <NUM>. For some embodiments, the sheet metal is bent to form the horizontal member <NUM>, and the second longitudinal side <NUM> ends just below the region of the bent forming the horizontal member <NUM>.

With reference to <FIG>, for some embodiments, when the bumper beam <NUM> is attached to a main body <NUM> of a vehicle, the horizontal member <NUM> and/or the first longitudinal side <NUM> may be configured to point at least in a direction toward the main body <NUM> of the vehicle. For some embodiments, when the bumper beam <NUM> is attached to a main body <NUM> of a vehicle, the recess <NUM> may be configured to open in a direction away from the main body <NUM> of the vehicle. For some embodiments, when the bumper beam <NUM> is attached to a main body <NUM> of a vehicle, the horizontal member <NUM> and/or the first longitudinal side <NUM> may be configured to extend into the recess <NUM> at least in a direction toward the main body <NUM> of the vehicle.

With reference to <FIG>, for some embodiments, the closed hollow structure <NUM> may be described to have an outer side <NUM> and an inner side <NUM>. The outer side <NUM> faces away from the horizontal member <NUM>. The second longitudinal side <NUM> may be welded to the outer side <NUM> of the closed hollow structure <NUM>.

With reference to <FIG>, for some embodiments, the first longitudinal side <NUM> may be described to have a longitudinal edge <NUM>. In the recess <NUM>, there may be a gap <NUM> or distance <NUM> between the longitudinal edge <NUM> of the first longitudinal side <NUM> and the second side wall <NUM> at least before any deformed due to an impact. For some embodiments, the horizontal member <NUM> may extend into, but with a gap <NUM> or distance <NUM> between the longitudinal edge <NUM> of the first longitudinal side <NUM> and the recess <NUM> when the bumper beam <NUM> is manufactured. For some embodiments, the gap <NUM> or distance <NUM> may be between a few millimetres and the depth of the recess <NUM>.

With reference to <FIG>, for some embodiments, the second longitudinal side <NUM> may end in a region of the horizontal member <NUM>. The closed hollow structure <NUM> may be obtained by roll forming. For some embodiments, the recess <NUM> may be described to open toward the horizontal member <NUM> and/or open to the inner space <NUM>.

With reference to <FIG>, for some embodiments, the bumper beam <NUM> has a certain closed profile with an upper and a lower generally rectangular section <NUM>, <NUM> that are interconnected by a central section <NUM>. One side wall <NUM> of the central section may be generally planar and vertical, for example when attached to a main body <NUM> of a vehicle. The bumper beam <NUM> may be roll-formed to the profile shown in the figures such that a first side <NUM> of the roll-formed steel sheet is bent to form a generally planar and horizontal inner element <NUM>, or member <NUM>, or web <NUM>. The second side <NUM> of the steel sheet may end just below the bending area of the first side <NUM> and may be welded thereto with a weld <NUM>. In this regard, a number of different welding solutions may be employed, such as resistance welding, spot or continuous, arc welding, laser welding, just to mention a few. However, the first side <NUM> is not welded but extends into a profiled recess <NUM> in a second side wall <NUM> of the central section as illustrated in <FIG>. In order to avoid vibrations and noise due to contact between the first side <NUM> and the recess <NUM>, there may be a small gap or distance <NUM> between them.

With reference to <FIG>, for some embodiments, the distance <NUM> may be some millimetres, but it may be taken into account that the edge of the first side <NUM> may be somewhat wavy due to the manufacturing process, such as roll-forming, which could occur in particular if the bumper beam <NUM> is bent to follow the shape of a vehicle front or back. However, the distance could be larger, up to the start of the recess <NUM> on the inner surface of the second side wall <NUM>, for example as indicated by line <NUM> in <FIG>, thus depending on the depth of the recess <NUM>. This may also be advantageous with regard to prevention of corrosion inside the bumper beam <NUM>. The design of the bumper beam <NUM> may be obtained by roll forming technology with only one weld, wherein the roll forming may follow conventional and known methods known to the skilled person.

For some embodiments, if the bumper beam <NUM> is exposed to an impact, the first side <NUM> will be moved into contact with the recess <NUM>, or into contact with the second side wall <NUM> and/or the wall portion <NUM> of the second side wall <NUM>, thereby acting as a reinforcement of the bumper beam <NUM>. This is schematically illustrated in <FIG>. The first side <NUM> and/or the horizontal member <NUM> will also, together with the rest of the profiled bumper beam, act as an energy absorber, or as an impact energy absorber.

With reference to <FIG>, as seen in a simulated point impact, the profiled bumper beam will be compressed and the inner element <NUM>, or member <NUM>, may be bent as seen in <FIG>. An advantageous feature is that the gap <NUM> or distance <NUM> is chosen such that it is assured that the first side <NUM> enters into the recess <NUM> and is "locked" by the recess <NUM> of the second side wall <NUM>, so that the first side <NUM> is prevented from sliding upwards or downwards along the second side wall <NUM> of the central section <NUM>. This assures a reinforcement of the bumper beam <NUM>. This design also excludes the need for welding the first side <NUM> to the second side wall <NUM>, as is done conventionally. Thus, the production of the bumper beam <NUM> is simplified, or facilitated, and thus made faster, and the production cost is reduced. With reference to <FIG>, the impact, or impact energy, affecting the bumper beam <NUM> is coming from the left and toward the bumper beam <NUM>, for example when the moving vehicle hits an external object to the left of the bumper beam <NUM> in <FIG>.

Even though the bumper beam <NUM> illustrated in the drawings has a specific profile, it is to be understood that the bumper beam <NUM> may have a number of other profiles while using the reinforcement described above.

Claim 1:
A bumper beam (<NUM>) of a sheet metal formed to a closed hollow structure (<NUM>) comprising a first side wall (<NUM>) and a second side wall (<NUM>),
wherein the sheet metal comprises a first longitudinal side (<NUM>) and a second longitudinal side (<NUM>),
wherein the sheet metal is formed such that the first longitudinal side (<NUM>) is formed to a horizontal member (<NUM>) located inside the closed hollow structure (<NUM>) and such that the second side wall (<NUM>) forms a recess (<NUM>) into which the first longitudinal side (<NUM>) extends,
wherein the first longitudinal side (<NUM>) and the recess (<NUM>) are configured to form a locking of the horizontal member (<NUM>) when the bumper beam (<NUM>) is deformed due to an impact,
wherein the second longitudinal side (<NUM>) is welded to the closed hollow structure (<NUM>),
characterized in that, in the recess (<NUM>), the first longitudinal side (<NUM>) is unwelded to the second side wall (<NUM>).