Patent Publication Number: US-2022234535-A1

Title: Support structure for a vehicle and method for assembling parts of a support structure for a vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims benefit of priority to European Patent Application No. 21153444.1, filed Jan. 26, 2021, and is assigned to the same assignee as the present application and is incorporated herein by reference. 
     TECHNICAL FIELD 
     The disclosure relates to a support structure for a vehicle and to a method for assembling parts of the support structure for a vehicle. In particular, the disclosure relates to a method for simplifying the assembly of a large support structure such as a roll-over protection structure, and to a support structure assembled using the described method. 
     The disclosure can be applied in heavy-duty vehicles, such as construction machines, trucks, buses, and other construction equipment and vehicles. Accordingly, although the disclosure will be described with respect to a support structure for a construction machine such as a wheel loader, the disclosure is not restricted to this structure or vehicle but may also be used in other types of structures and for other types of vehicles. 
     BACKGROUND 
     Working machines such as wheel loaders, dumpers, excavators, and the like are often operated in dangerous environments and it is therefore important to provide appropriate protection for a vehicle operator. There may for example be a risk of objects falling on the machine or of the machine tipping over in which case a vehicle operator must be well protected inside the vehicle cab. 
     To provide operator safety, heavy duty vehicles often include support structures reinforcing the vehicle cab, sometimes referred to as a roll-over protection structure (ROPS). A ROPS needs to be mechanically robust and to achieve this it is often manufactured and assembled as one piece. 
     However, such a support structure is relatively large and may require specialized tools and manufacturing lines for assembly. In particular, known manufacturing methods involve welding in the final assembly operations. This means that surface treatment such as corrosion protection and/or painting cannot be performed until after the full structure is assembled. Thereby, surface treatment must be performed on the final support structure as a whole, which due to its weight and size requires specialized and sometimes costly and complicated tools. 
     Accordingly, in view of the above it is desirable to simplify manufacturing and assembly of large support structures for vehicles. 
     SUMMARY 
     An object of the disclosure is to provide a simplified method for assembling parts of a support structure for a vehicle. 
     The object is achieved by a method according to claim  1 . The method comprises providing a first part comprising a protruding connection element, wherein at least a portion of the connection element is configured to receive an adhesive; providing a second part in the form of a tubular element configured to be connected to the first part; depositing an adhesive on the portion of the protruding connection element configured to receive the adhesive; connecting first part to the second part by pressing the tubular element onto the protruding connection element; and attaching a fixation element to the first part and to the second part to fixate the first part in relation to the second part. 
     In the present context, the support structure may be any structure intended to provide mechanical support in or for a vehicle. The support structure comprises at least two parts assembled by the described method. However, the support structure may consist of a large number of parts where some are assembled using the described method and where other parts are assembled using other methods. 
     The present disclosure is based on the realization that a support structure consisting of multiple parts can be assembled by configuring a connectable tubular elements to be attached to another element using an adhesive in combination with a fixation element keeping the parts in place while allowing the adhesive to harden. An advantage of the described method is that various surface treatments of the different parts can be performed prior to assembly since no welding is required in the assembly process. This saves space in the assembly plant since there is no need for the whole of the finished support structure to undergo surface treatment. 
     A further advantage of the described method is that the fixation element holds the parts together while the adhesive hardens so that the support structure can proceed immediately to the next operation in the assembly line which saves time during assembly. The same advantages are present also for other support structures such as an engine hood frame or other structures where tubular elements are used. 
     According to one embodiment of the disclosure, the portion of the connection element configured to receive an adhesive comprises a recess, and the thickness of the adhesive is defined by the depth of the recess. The thickness and location of the adhesive is thereby easily controllable, which simplifies the method. 
     According to one embodiment of the disclosure, the protruding connection element comprises a ridge, and pressing the tubular element onto the protruding connection element comprises applying a force so that the ridge presses against an inner wall of the tubular element when the first and second parts are assembled. The ridge is configured to ensure that a tight seal is formed between the first and second parts, thereby preventing moisture and dirt from reaching the inside of the tubular element. Preferably, the ridge is arranged on an end portion of the connection element and aligned perpendicularly to the direction of insertion of the protruding connection element. 
     According to one embodiment of the disclosure, the method comprises attaching the fixation element using an attachment method not involving heating. The fixation element may for example be attached using screws, bolts, rivets, or the like. Thereby, the parts of the support structure can be pretreated prior to assembly using pretreatment methods and operations such as electroplating or painting. 
     According to one embodiment of the disclosure, the first element may be a corner element comprising a plurality of protruding connection elements, and the method may comprise attaching tubular elements to each of the protruding connection elements. Corner elements are used in support structures such as roll over protection structures, and by configuring the corner structures with several protruding connection elements as described, the remaining tubular elements can remaining unchanged, thus facilitating an implementation of the assembly method without the need to redesign all of the parts of the support structure. The corner element as such may be manufactured by means of welding, casting, or other methods. 
     According to a second aspect of the disclosure, the object is achieved by a support structure for a vehicle according to claim  9 . The support structure comprises: a first part comprising a protruding connection element, wherein at least a portion of the connection element is configured to receive an adhesive; a second part in the form of a tubular element, wherein the protruding connection element is arranged in an end portion of the tubular element; an adhesive arranged on the protruding connection element and configured to attach the first part to the second part; and a fixation element attached to the first part and to the second part to fixate the first part in relation to the second part. The support structure may for example be a roll over protection structure ROPS. 
     Effects and features of this second aspect of the present disclosure are largely analogous to those described above in connection with the first aspect of the disclosure. Further advantages and advantageous features of the disclosure are disclosed in the following description and in the dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       With reference to the appended drawings, below follows a more detailed description of embodiments of the disclosure cited as examples. 
       In the drawings: 
         FIGS. 1A-B  are schematic illustrations of parts of a support structure according to an embodiment of the disclosure; 
         FIG. 2  is a schematic illustration of a support structure according to an embodiment of the disclosure; 
         FIG. 3  is a flow chart outlining operations of a method according to an embodiment of the disclosure; and 
         FIG. 4  is a schematic illustration of a wheel loader comprising a support structure according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE DISCLOSURE 
     In the following detailed description, various embodiments of a support structure and a method for manufacturing a support structure according to the present disclosure are mainly discussed with reference to a roll-over protection structure. It should be noted that this by no means limits the scope of the present disclosure which is equally applicable to other support structures for a vehicle. 
       FIG. 1A . is an exploded view schematically illustrating parts of a support structure and  FIG. 1B  illustrates a corner element  100  of a support structure.  FIG. 1A  illustrates a first part  100  comprising a protruding connection element  102 , wherein at least a portion  104  of the connection element is configured to receive an adhesive  112 . The first part  100  is here a corner element  100  of a support structure. The second part  106  is a tubular element  106  and the protruding connection element  102  is configured to be inserted into an end portion  107  of the tubular element  106 . The support structure further comprises a fixation element  108  configured to be attached to the first part  100  and to the second part  106  to fixate the first part  100  in relation to the second part  106 . 
       FIG. 1B  illustrates details of the corner element  100 . In particular,  FIG. 1B  illustrates that the protruding connection element  102  which is a part of the corner element  100  comprises portions  104  configured to receive an adhesive  112 . The portions  104  are for example recessed to receive an adhesive where the thickness of the adhesive is determined by the depth of the recess. The recess may cover part or all of the surface of one or more sides of the connection element  102 . Moreover, the recess may be formed with edges or walls so that an adhesive stay within the recess once deposited. The surface of the portions  104  configured to receive the adhesive may further be roughened through grinding, milling or other means in order to provide a surface roughness improving the adhesion of the adhesive to be used. Other types of surface treatments are also feasible for achieving desirable surface properties of the portions  104  of the connection element  102  configured to receive the adhesive. Moreover, the portions  104  may be adapted to receive an adhesive by comprising grooves, trenches, ridges, pits or the like. 
       FIG. 1B  further illustrates that the protruding connection element  102  comprises a ridge  110  configured to press against an inner wall of the tubular element  106  at the end portion  107  of the tubular element  106  when the tubular element  106  pressed onto the connection element  102 . The connection element  102  may comprise a ridge  110  on one surface as illustrated in  FIG. 1B , bit it may equally well be provided with ridges or similar protruding elements on multiple sides. Moreover, the skilled person readily realizes that structures of another shape are also possible aside from a ridge. 
     The ridge  110  ensures that a tight seal is formed between the connection element  112  and the tubular element  106  such that moisture and dirt is prevented from reaching the inside of the tubular element  106 . The ridge is located at an end portion  111  of the connection element  102  closest to the final joint, i.e. the end portion  111  closest to the opening of the tubular element  106  once the two parts are assembled. The ridge  110  also helps to keep the two parts  100 ,  106  together to allow the fixation element  108  to be attached. The fixation element  108  is here exemplified by a plate  108  comprising holes  114  for receiving screws so that the plate  108  can be attached to the corner element  100  and the tubular element  106 . 
       FIG. 2  illustrates a roll-over protection structure  200  comprising the corner element  100  and attached tubular elements  106 . 
       FIG. 3  is a flow chart outlining operations of the method for assembling parts of a support structure  200  for a vehicle, and the method will be described with further reference to  FIGS. 1-2 . The method comprises providing  300  a first part  100  comprising a protruding connection element  102 , wherein at least a portion of the connection element  112  is configured  104  to receive an adhesive; The next operation comprises the providing  302  a second part  106  in the form of a tubular element configured to be connected to the first part  100 . 
     In the following operation, an adhesive  112  is deposited  304  on the portion or portions  104  of the protruding connection element configured to receive the adhesive. The adhesive may for example be deposited using a glue pistol, either manually or by means of an automated process. Other means of deposition are also possible. 
     Next, the first part  100  is connected  306  to the second part  106  by pressing the tubular element  106  onto the protruding connection element  102  Finally, a fixation element  108  is attached  308  to the first part  100  and to the second part  106  to fixate the first part  100  in relation to the second part  106 . The adhesive is advantageously an anaerobic adhesive which hardens over time in room temperature. The support structure  200  is thereby sufficiently held together by the ridge  110  of the connection element  102  and/or the fixation element  108  so that it can proceed directly to the next step in the assembly line where the adhesive hardens over time during further assembly. 
     Prior to providing the first and second parts  100 ,  106 , the parts may have been electro-plated and/or painted, or subjected to any other pre-treatment steps which are temperature sensitive. 
       FIG. 4  schematically illustrates a wheel loader  400  comprising a roll-over protection structure  200  according to an embodiment of the disclosure. 
     Even though the disclosure has been described with reference to specific exemplifying embodiments thereof, many different alterations, modifications and the like will become apparent for those skilled in the art. For example, many different types of structures can be assembled using the described method. Also, it should be noted that parts of the system may be omitted, interchanged or arranged in various ways, the method and support structure yet being able to perform the functionality of the present disclosure. 
     Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the embodiments of the disclosure, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or operations, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.