Patent Description:
The propulsion systems of vehicles are continuously developed to meet the demands from the market. A particular aspect relates to the emission of environmentally harmful exhaust gas. Therefore, vehicles propelled by electric machines have been increasingly popular, both for cars as well as for trucks and other heavy duty vehicles.

In relation to heavy duty vehicles, the battery connected to the electric machine propelling the vehicle needs to be relatively large to be able to deliver a substantial amount of electric power to the electric machine(s), in particular when aiming for covering a long driving range without having to charge the battery.

A conventional placement of the batteries in a heavy duty vehicle is along the longitudinally extending frame rails of the vehicle. This is substantially the same position as used for the fuel tanks of a truck using an internal combustion engine for propulsion. However, this position does not make room for sufficiently large batteries and the conventional frame rails are not dimensioned for the relatively large load of vehicle batteries. There is thus a desire to improve the vehicle structure to handle vehicle batteries of sufficient size.

<CIT> relates to a light-weight structure of a four-wheel electric car frame. The light-weight structure of the four-wheel electric car frame comprises frame main beams, wherein two ends of each frame main beam are respectively provided with a front suspension and a rear suspension, the frame main beam is a square hollow aluminum alloy sectional material, a load-bearing support is arranged in an inner cavity of the frame main beam, and the load-bearing support is in an X shape.

<CIT> relates to a cross member for a frame of a vehicle. The cross member provides a particularly high stiffness of the frame and has a particularly low weight.

It is an object of the present invention to provide a frame structure that at least partly overcomes the above-described deficiencies. This object is achieved by a frame structure according to claim <NUM>.

According to a first aspect, there is provided a frame structure for a vehicle comprising a front wheel suspension arrangement for suspending a pair of front wheels of the vehicle, and a rear wheel suspension arrangement for suspending a pair of rear wheels of the vehicle, wherein the frame structure comprises a load bearing frame arrangement arranged to be positioned at a transversal center portion of the vehicle, the load bearing frame arrangement comprising a first member and a second member, each of the first and second members forming a diagonal extension as seen in a transversal cross section of the load bearing frame arrangement, wherein the diagonal first and second members extend longitudinally between the front wheel suspension arrangement and the rear wheel suspension arrangement, wherein the diagonal extension of the first member interconnects with the diagonal extension of the second member forming a connection point between the first and second members.

The load bearing frame arrangement is preferably occupying the position of a conventional propeller shaft. Since the vehicle preferably does not comprise such a propeller shaft, the load bearing frame arrangement can be arranged at this position. The diagonal extension of the first and second members will increase the stiffness of the load bearing frame arrangement which can absorb the load generated by relatively heavy vehicle batteries connected to the frame. Also, the diagonal extension of the first and second members present an improved bending stiffness as well as an improved torsional stiffness.

Furthermore, as the load bearing frame arrangement is arranged at the transversal center portion of the vehicle, larger batteries can be arranged on each side of the load bearing frame arrangement compared to conventional longitudinally extending frame rails of the vehicle, since there is more available space for the batteries. Furthermore, and as will be described in further detail below, the diagonal extension of the first and second members enables for channels/space that allows for packaging of routing highways, power electronic components and other components. Also, an easier and more rapid assembly of larger modules is provided since premounting of routing and components on the diagonal first and second members are possible.

According to an example embodiment, the connection point may be positioned along the diagonal extension of the first and second members. Thus, the loads absorbed by the load bearing frame arrangement is directed through the connection point. Preferably, and according to an example embodiment, the connection point may be arranged to be positioned at the transversal center portion of the vehicle.

According to an example embodiment, the first and second members may be connected to each other by a fastening element to form the connection point. In such a case, the first and second members are formed as separate components connected to each other. An advantage is that a simplified manufacturing process is provided. The first and second members may preferably be formed as ninety degrees rotated V-shaped portions. According to an example embodiment, the diagonal extension of the first member may interconnect with the diagonal extension of the second member forming an X-shaped, longitudinally extending, load carrying beam. In the case of rotated V-shaped portions, these can thus be connected to each other to form the X-shape. The X-shaped load bearing frame arrangement can however be formed as one solid portion, whereby the connection point is formed by the waist portion of the X-shape.

According to the invention, the frame structure further comprises a plurality of brackets connected to the load bearing frame arrangement. The brackets can increase the stiffness of the frame structure while at the same time serve as connector elements for the vehicle battery/batteries. According to the invention, each of the plurality of brackets are connected to the load bearing frame arrangement and extends transversally away from the connection point. Hereby, the brackets can protect the batteries during e.g. a side collision as the load from such side collision will be directed through the bracket directly to the stiff load bearing frame arrangement.

According to the invention, the brackets are positioned along the longitudinal extension of the load bearing frame arrangement at a predetermined distance from each other. Hereby, battery modules may be connected to the frame structure between a pair of brackets.

According to an example embodiment, the frame structure may further comprise an upper panel structure fixated to a vertical upper portion of the load bearing frame arrangement. The upper panel may even further increase the stiffness of the frame structure. Preferably, and according to an example embodiment, the upper panel structure may comprise an extension in the transversal and longitudinal direction of the load bearing arrangement. The upper panel may also preferably be supported by, and connected to, the above-described brackets. According to an example embodiment, the upper panel structure may be fixated to a vertical upper portion of the plurality of brackets.

According to an example embodiment, the upper panel structure may comprise an access lid positioned vertically above the connection point. Hereby, access to a cavity formed between the upper panel structure and the connection point is provided. The cavity can thus serve as a location for storing e.g. high voltage cables, low voltage cables, cooling pipes, pneumatic pipes, etc. Other components and structures can of course also be arranged in this cavity and the access lid allows an operator to gain access to these components and structures. The access lid can be arranged directly above the connection point.

According to an example embodiment, the frame structure may further comprise a lower panel structure fixated to a vertical lower portion of the load bearing frame arrangement. The stiffness of the frame structure can hereby be even further improved. The upper and lower panel structure, together with the load bearing frame arrangement thus form a high strength "box-shaped structure".

According to a second aspect, there is provided a vehicle, comprising a front wheel suspension arrangement for suspending a pair of front wheels of the vehicle, and a rear wheel suspension arrangement for suspending a pair of rear wheels of the vehicle, and a frame structure according to any one of the embodiments described above in relation to the first aspect, wherein the frame structure extends between the front wheel suspension arrangement and the rear wheel suspension arrangement.

According to an example embodiment, the vehicle may comprise a electric machine for propelling the vehicle, the vehicle further comprises a plurality of vehicle batteries electrically connected to the electric machine, wherein the vehicle batteries are connected to the load bearing frame arrangement transversally outside the connection point.

The above, as well as additional objects, features and advantages of the present disclosure, will be better understood through the following illustrative and non-limiting detailed description of exemplary embodiments, wherein:.

With initial reference to <FIG>, there is provided a vehicle <NUM> in the form of a truck. The vehicle <NUM> illustrated in <FIG> comprises a pair of front wheels <NUM> and a pair of rear wheels <NUM>. It should however be readily understood that the vehicle <NUM> may equally as well comprise a first pair of rear wheels and a second pair of rear wheels, where the first pair of wheels is positioned longitudinally in front of the second pair of rear wheels. The second pair of rear wheels may be connected to a so-called tag-axle and the first pair of rear wheels may be connected to a so-called pusher axle.

Furthermore, the vehicle <NUM> comprises a plurality of modules <NUM> arranged to supply power for propelling an electric machine (not shown) of the vehicle <NUM>. The vehicle <NUM> is thus operated using at least one electric machine, which can be arranged in the form of wheel hub motors or a single electric motor connected to e.g. the pair of front wheels. The modules <NUM> may thus form a plurality of vehicle batteries for supplying electrical power to the electric machine. The modules <NUM> may on the other hand, as an alternative, form a plurality of hydrogen tanks comprising hydrogen fuel which is supplied to a fuel cell system that generates electric power to be supplied to a battery or directly to the electric machine.

As is further illustrated in <FIG>, the vehicle comprises a frame structure <NUM>. The frame structure comprises a front wheel suspension arrangement <NUM> and a rear wheel suspension arrangement <NUM>. The front <NUM> and rear <NUM> wheel suspension arrangements are not depicted in detail in <FIG> but should be understood to suspend the pair of front wheels <NUM> and pair of rear wheels <NUM>, respectively. The frame structure <NUM> further comprises a load bearing frame arrangement <NUM> (see <FIG>) extending between the front <NUM> and rear <NUM> wheel suspension arrangements. The vehicle <NUM> depicted in <FIG> does hence not contain a conventional frame structure which is composed of two longitudinally extending frame rails positioned at a transversal distance from each other. Instead, the frame structure <NUM> comprises the load bearing frame arrangement <NUM> which is positioned at a transversal center portion of the vehicle <NUM>. Since the vehicle is propelled by electric machine(s), the vehicle does not contain a conventional propeller shaft. The load bearing frame arrangement <NUM> is therefore preferably positioned in the space which, for an ICE operated vehicle, is conventionally occupied by such propeller shaft.

In order to describe the frame structure <NUM> in further detail, reference is now made to <FIG>. As can be seen, the frame structure <NUM> comprises the above mentioned load bearing frame arrangement <NUM> which is, when arranged on the vehicle <NUM>, positioned at a transversal center portion and extending in the longitudinal direction of the vehicle <NUM>. The load bearing frame arrangement <NUM> comprises a first member <NUM> and a second member <NUM>. The first <NUM> and second <NUM> members are extending in the longitudinal direction of the vehicle <NUM> between, as also indicated above, between the front <NUM> and rear <NUM> wheel suspension arrangements. Further, and as seen in a transversal cross section of the load bearing frame arrangement <NUM>, each of the first <NUM> and second <NUM> members comprises an extension in a diagonal direction, which are indicated by arrows numbered <NUM> and <NUM>. The diagonal extension <NUM> of the first member <NUM> interconnects with the diagonal extension <NUM> of the second member <NUM>, thereby forming a connection point <NUM> between the first <NUM> and second <NUM> members. The load bearing frame arrangement <NUM> is hereby forming an X-shaped, longitudinally extending, load carrying beam.

Preferably, and as illustrated in <FIG>, the connection point <NUM> is positioned along the diagonal extension of first <NUM> and second <NUM> member, preferably at the transversal center portion of the vehicle <NUM>. The first <NUM> and second <NUM> members may, as illustrated in <FIG>, be formed by a respective first and second plate structure, which plate structures are connected to each other at the connection point <NUM> by fastening elements <NUM>. The fastening elements <NUM> can, for example, be formed by screw joints, bolts, rivets, welds, etc. The first <NUM> and second <NUM> members are in this configuration formed as a respective rotated V-shaped member which are fixated to each other to form the X-shaped beam.

As an alternative, the X-shaped beam can be formed in one piece in which the above-described fastening elements <NUM> are superfluous. The X-shaped beam can be formed as a one piece structure by casting or extrusion, etc. A one piece X-shaped beam still comprises the connection point <NUM> between the diagonally extending first and second members.

As is further illustrated in <FIG>, each of the first <NUM> and second <NUM> members comprises a substantially horizontal upper support portion <NUM> as well as a substantially horizontal lower support portion <NUM>. The upper <NUM> and lower <NUM> support portions are arranged as support surfaces for connecting to an upper and a lower panel structure (see <NUM> and <NUM> in <FIG>). The upper panel structure <NUM> is connected to the load bearing frame arrangement <NUM> at the upper support portion <NUM> by means of suitable fastening elements <NUM>, such as e.g. screws, bolts, rivets, welds, etc. In a similar vein, the lower panel structure <NUM> is connected to the load bearing frame arrangement <NUM> at the lower support portion <NUM> by means of suitable fastening elements <NUM>, such as e.g. screws, bolts, rivets, welds, etc..

Turning now to <FIG> which illustrates the above-described frame structure <NUM> according to an example embodiment. As described above, the frame structure <NUM> comprises the X-shaped load bearing frame arrangement <NUM>. As can be seen in <FIG>, the upper <NUM> and lower <NUM> panel structures connected to the load bearing frame arrangement <NUM> by means of the fastening elements <NUM>. The upper <NUM> and lower <NUM> panel structures each has an extension in the transversal direction as well as in the longitudinal direction of the vehicle <NUM>, thereby forming a "roof" and "floor" for the frame structure <NUM>. Preferably, and as illustrated in <FIG>, the upper <NUM> and lower <NUM> panels extend between the front <NUM> and rear <NUM> wheel suspension arrangements, thereby forming a full cover both above as well as below the X-shaped load bearing frame arrangement <NUM>. The upper panel structure <NUM> is, together with the load bearing frame arrangement <NUM>, forming an upper volume <NUM> or cavity. In particular, an upper portion of the load bearing frame arrangement <NUM> is arranged in a V-shape, which forms the upper volume <NUM> or cavity. In a similar vein, the lower panel structure <NUM> is, together with the load bearing frame arrangement <NUM>, forming a lower volume <NUM> or cavity. In particular, a lower portion of the load bearing frame arrangement <NUM> is arranged in a reversed V-shape, which forms the lower volume <NUM> or cavity. The upper <NUM> and lower <NUM> volumes/cavities are advantageously used for packaging of components, such as routing of media, cablings, etc. As is also illustrated in <FIG>, the upper panel structure <NUM> comprises an access lid <NUM>. Hereby, the components positioned within the upper volume <NUM> are accessible by an operator of the vehicle, or during maintenance. Although not depicted in the figures, the lower panel structure may also comprise a similar access lid for gaining simplified access to the lower volume <NUM>.

The frame structure <NUM> further comprises a plurality of brackets <NUM> arranged laterally outside the load bearing frame arrangement <NUM>. In particular, each of the brackets are connected to the load bearing frame arrangement <NUM> and extends in a direction transversally away from the above-described connection point <NUM>. The brackets <NUM> are positioned along the longitudinal extension of the load bearing frame arrangement <NUM> at a predetermined distance from each other. The brackets <NUM> are preferably connected to the load bearing frame arrangement <NUM> by means of fastening elements <NUM>, such as screws, bolts, rivets, etc. The brackets <NUM> are further also attached/connected to the upper <NUM> and lower <NUM> panel structures by means of bracket connectors <NUM> in the form of e.g. screws, bolts, rivets, etc..

The brackets <NUM>, together with the load bearing frame arrangement <NUM>, the upper panel structure <NUM> and the lower panel structure <NUM> forms a cavity <NUM> in which the modules <NUM>, in the following merely referred to as batteries/battery modules, can be positioned. In particular, one or more battery modules can be arranged between a pair of brackets in the cavity <NUM> formed therebetween. The batteries are, after insertion to the cavity <NUM>, fixated to the frame structure in a suitable manner. By arranging the battery modules in this manner, the brackets will act as a load transferring element in case of e.g. a side collision. The load from such a side collision will thus be transferred to the load bearing frame arrangement <NUM> via the brackets <NUM>, thereby protecting the batteries form damage.

Claim 1:
A frame structure (<NUM>) for a vehicle comprising a front wheel suspension arrangement for suspending a pair of front wheels of the vehicle, and a rear wheel suspension arrangement for suspending a pair of rear wheels of the vehicle, wherein the frame structure (<NUM>) comprises a load bearing frame arrangement (<NUM>) arranged to be positioned at a transversal center portion of the vehicle, the load bearing frame arrangement (<NUM>) comprising a first member (<NUM>) and a second member (<NUM>), each of the first and second members forming a diagonal extension as seen in a transversal cross section of the load bearing frame arrangement, wherein the diagonal first and second members extend longitudinally between the front wheel suspension arrangement and the rear wheel suspension arrangement, wherein the diagonal extension of the first member (<NUM>) interconnects with the diagonal extension of the second member (<NUM>) forming a connection point (<NUM>) between the first and second members, characterized in that the frame structure (<NUM>) further comprises a plurality of brackets positioned along the longitudinal extension of the load bearing frame arrangement at a predetermined distance from each other, wherein each of the plurality of brackets is connected to the diagonally extending first (<NUM>) and second (<NUM>) members and extends transversally away from the connection point.