Patent Publication Number: US-2023150589-A1

Title: Stiffness improvement structure of vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to Korean Patent Application No. 10-2021-0157624, filed on Nov. 16, 2021, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND OF PRESENT DISCLOSURE 
     Field of Present Disclosure 
     The present disclosure relates to a stiffness improvement structure of a vehicle, in which vehicle body stiffness is improved by reinforcing stiffness of a towed portion of a vehicle body being towed. 
     Description of Related Art 
     An articulated bus is transportation which increases a transportation capacity by connecting and driving a plurality of vehicle bodies to each other. 
     In the articulated bus, an articulated unit for connecting the vehicle bodies is provided therebetween. 
       FIG.  1    illustrates an example of an articulated bus  100  in which a front body  110  and a rear body  120  are connected through an articulated unit  130 . 
     In the articulated unit  130 , a first articulated plate  131  provided at a rear end of the front body  110  is hinged to a second articulated plate  132  provided at a front end of the rear body  120 . Due to the articulated unit  130 , the articulated bus may be easily bent even in a curved section, being driven without departing from a lane. 
     Meanwhile, in recent years, with the electrification of a vehicle driving device, the spread of the articulated electric bus using a driving motor instead of using an internal combustion engine is also expanding. 
     The articulated electric bus utilizes a roof of the rear body  120  as a mounting space for a battery B for supplying electric power to the driving motor, and thus there is a problem in that, since a load of the battery B is applied to a front end of the rear body  120 , a portion in which the second articulated plate  132  and the rear body  120  are connected is sheared. 
     The second articulated plate  132  and the rear body  120  are engaged with each other using bolts (see portion A of  FIG.  3   ), and a load is applied to the articulated unit  130  while traveling and transmitted to a rear side of the rear body  120  along a frame of the rear body  120  (see arrow B of  FIG.  3   ). The rear body  120  is formed so that tubes  120  and  121 , each having a rectangular cross-section, are provided in a longitudinal direction and a width direction of the rear body  120  and are bonded to each other. However, in the rear body  120 , the load is transmitted only through some tubes, and there is no structure for reinforcing stiffness of a portion where different tubes are bonded to each other. 
     Accordingly, there is a problem in that stress is concentrated in some tubes, and thus the tube forming the rear body  120  is sheared. 
     Problems in that a connection portion between the second articulated plate  132  and the rear body  120  is sheared or a connection portion of the tube forming the rear body  120  is sheared may occur not only in the articulated electric bus but also in an articulated bus provided with an internal combustion engine. 
     The information included in this Background of the present disclosure section is only for enhancement of understanding of the general background of the present disclosure and may not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
     BRIEF SUMMARY OF PRESENT DISCLOSURE 
     Various aspects of the present disclosure are directed to providing a stiffness improvement structure of a vehicle, in which a load which acts during traveling on a towed vehicle body, such as a rear body of an articulated bus, is distributed and transmitted, and thus stiffness of a connection portion of a tube is increased to improve stiffness of the rear body. 
     Other objects and advantages of the present disclosure may be understood by the following description and become apparent with reference to the exemplary embodiments of the present disclosure. Also, it is obvious to those skilled in the art to which the present disclosure pertains that the objects and advantages of the present disclosure may be realized by the means as claimed and combinations thereof. 
     In accordance with an exemplary embodiment of the present disclosure, there is provided a stiffness improvement structure of a vehicle, which reinforces stiffness of the vehicle by being provided in a vehicle body including a transverse frame formed in a width direction of the vehicle and a longitudinal frame formed in a longitudinal direction of the vehicle, the stiffness improvement structure including: a plurality of transverse reinforcement frames formed in parallel to the transverse frame and provided with an interval from each other in a longitudinal direction of the vehicle, and a plurality of longitudinal reinforcement frames formed in parallel to the longitudinal frame and provided with an interval from each other in the width direction of the vehicle, wherein a front end portion and a rear end portion of each of the longitudinal reinforcement frames are bonded to the transverse frame and the transverse reinforcement frames or bonded to the transverse reinforcement frames spaced from each other, a connection frame coupled to an articulated plate for connecting the body to another body is provided in the transverse frame, and end portions of the longitudinal reinforcement frames, which are engaged with the transverse frame, are bonded at a portion engaged with the connection frame in the transverse frame. 
     The connection frame may be engaged with the transverse frame provided on a front end portion of the body. 
     The transverse reinforcement frame may include a first transverse reinforcement frame spaced from the transverse frame, and a second transverse reinforcement frame spaced from the first transverse reinforcement frame toward a rear side of the vehicle, wherein both end portions of each of the first transverse reinforcement frame and the second transverse reinforcement frame may be bonded to the longitudinal frame, and the longitudinal reinforcement frame may be provided between the transverse frame and the first transverse reinforcement frame and between the first transverse reinforcement frame and the second transverse reinforcement frame. 
     The longitudinal reinforcement frame may include an internal longitudinal reinforcement frame provided adjacent to a center portion of the transverse frame in the width direction, and an external longitudinal reinforcement frame provided toward an external side of the vehicle from the internal longitudinal reinforcement frame. 
     The internal longitudinal reinforcement frame may include a first internal longitudinal reinforcement frame of which a front end portion is bonded to the transverse frame and of which a rear end portion is bonded to the first transverse reinforcement frame, and a second internal longitudinal reinforcement frame of which a front end portion is bonded to the first transverse reinforcement frame and of which a rear end portion is bonded to the second transverse reinforcement frame, wherein the first internal longitudinal reinforcement frame and the second internal longitudinal reinforcement frame may be provided on an imaginary line formed in the longitudinal direction of the vehicle to form a load transfer path. 
     The stiffness improvement structure may further include a patch member provided on a portion in which the first internal longitudinal reinforcement frame and the first transverse reinforcement frame are bonded, to reinforce bonding stiffness of the portion. 
     A width of the patch member may be formed in a range from 50% to 100% of a width of the first internal longitudinal reinforcement frame. 
     The stiffness improvement structure may further include a patch member provided on a portion in which the second internal longitudinal reinforcement frame is bonded to the first transverse reinforcement frame and the second transverse reinforcement frame to reinforce bonding stiffness of the portion. 
     A width of the patch member may be formed in a range from 50% to 100% of a width of the second internal longitudinal reinforcement frame. 
     The external longitudinal reinforcement frame may include a first external longitudinal reinforcement frame of which a front end portion is bonded to the transverse frame and of which a rear end portion is bonded to the first transverse reinforcement frame, and a second external longitudinal reinforcement frame of which a front end portion is bonded to the first transverse reinforcement frame and of which a rear end portion is bonded to the second transverse reinforcement frame, wherein the front end portion of the first external longitudinal reinforcement frame may be bonded to the transverse frame at the external side of the vehicle in the width direction rather than the end portion of the connection frame in the transverse frame, and the first external longitudinal reinforcement frame and the second external longitudinal reinforcement frame may be provided on an imaginary line formed in the longitudinal direction of the vehicle to form a load transfer path. 
     The stiffness improvement structure may further include a reinforcement member provided on a portion in which the first external longitudinal reinforcement frame is bonded to the first transverse reinforcement frame to distribute stress at the portion. 
     A length of the reinforcement member may be formed to be greater than a width thereof. 
     A width of the reinforcement member may be formed to be the same as a width of the first external longitudinal reinforcement frame. 
     The stiffness improvement structure may further include a patch member provided on a portion in which the second external longitudinal reinforcement frame is bonded to the second transverse reinforcement frame, to reinforce bonding stiffness of the portion. 
     A width of the patch member may be formed in a range from 50% to 100% of a width of the second external longitudinal reinforcement frame. 
     The stiffness improvement structure may further include a rear center frame member located on the rear side of the vehicle rather than the second internal longitudinal reinforcement frame and forming a load transfer path together with the first internal longitudinal reinforcement frame and the second internal longitudinal reinforcement frame. 
     The rear center frame member may be provided on an imaginary line formed in the longitudinal direction of the vehicle together with the first internal longitudinal reinforcement frame and the second internal longitudinal reinforcement frame. 
     The vehicle may be an articulated bus in which a front body and a rear body thereof are connected through an articulated unit. 
     The vehicle may be an articulated electric bus which is driven by electric power of a battery. 
     The methods and apparatuses of the present disclosure have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram illustrating a related articulated bus. 
         FIG.  2    is a schematic diagram illustrating an articulated unit in the articulated bus. 
         FIG.  3    is a bottom perspective view exemplarily illustrating a rear frame according to the related art. 
         FIG.  4    is a bottom perspective view exemplarily illustrating a rear body to which a stiffness improvement structure of a vehicle is applied according to an exemplary embodiment of the present disclosure. 
         FIG.  5    is a schematic view exemplarily illustrating a load transfer path in the rear body to which the stiffness improvement structure of a vehicle is applied according to an exemplary embodiment of the present disclosure. 
         FIG.  6    is a schematic view exemplarily illustrating a state in which a reinforcement member and a patch member are applied according to the stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure. 
         FIG.  7    is an enlarged perspective view exemplarily illustrating a portion to which a reinforcement member is applied according to the stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure. 
         FIG.  8    is an enlarged perspective view exemplarily illustrating a portion to which a patch member is applied according to the stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure. 
         FIG.  9    is a schematic view exemplarily illustrating a path through which a load is transferred from the rear body to a rear center body according to the stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure. 
     
    
    
     It may be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the present disclosure. The specific design features of the present disclosure as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particularly intended application and use environment. 
     In the figures, reference numbers refer to the same or equivalent parts of the present disclosure throughout the several figures of the drawing. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to various embodiments of the present disclosure(s), examples of which are illustrated in the accompanying drawings and described below. While the present disclosure(s) will be described in conjunction with exemplary embodiments of the present disclosure, it will be understood that the present description is not intended to limit the present disclosure(s) to those exemplary embodiments of the present disclosure. On the other hand, the present disclosure(s) is/are intended to cover not only the exemplary embodiments of the present disclosure, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the present disclosure as defined by the appended claims. 
     Hereinafter, a stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. 
     The stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure, which reinforces stiffness of the vehicle by being provided in a body  20  of the vehicle including a transverse frame  22  formed in a width direction of the vehicle and a longitudinal frame  23  formed in a longitudinal direction of the vehicle, includes a plurality of transverse reinforcement frames  22 F and  22 R formed in parallel to the transverse frame  22  and provided with an interval from each other in the longitudinal direction of the vehicle, and a plurality of longitudinal reinforcement frames  23 FI,  23 FO,  23 RI, and  23 RO formed in parallel to the longitudinal frame  23  and provided with an interval from each other in the width direction of the vehicle. A front end portion and a rear end portion of each of the longitudinal reinforcement frames  23 FI,  23 FO,  23 RI, and  23 RO are bonded to the transverse frame  22  and the transverse reinforcement frames  22 F and  22 R or bonded to the transverse reinforcement frames  22 F and  22 R which are spaced from each other. The transverse frame  22  is provided with a connection frame  21  which is engaged with an articulated plate  32  for connecting the body  20  to another body. End portions of the longitudinal reinforcement frames  23 FI,  23 FO,  23 RI, and  23 RO, which are engaged with the transverse frame  22 , are bonded to portions in which the transverse frame  22  is engaged with the connection frame  21 . 
     The stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure may be applied to an articulated bus in which a front body and the rear body  20  are connected to an articulated unit. 
     The stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure may be applied to an articulated electric bus which is driven by electric power of a battery. 
     The stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure is applied to the rear body  20  of the articulated electric bus. 
     When a front end portion of the rear body  20  is connected to the front body through the articulated unit, a load due to a tow of the front body acts, and because a heavy battery is mounted on an upper portion of the rear body  20 , stiffness reinforcement is necessary. 
     The rear body  20  is formed so that the transverse frame  22  and the longitudinal frame  23  are each provided in the width direction and the longitudinal direction of the vehicle and are bonded to each other to form a basic frame of the rear body  20 . 
     The stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure is applied to inside of the rear body  20  to reinforce stiffness of the rear body  20 , is connected to the front body to reinforce stiffness of a front side of the rear body  20  on which the battery is mounted. A connection frame  21  for coupling to the articulated plate  32  of the articulated unit is engaged with the transverse frame  22  of a front end portion of the transverse frame  22  in an intermediate portion of the transverse frame  22  located at the front end portion of the rear body  20 . The connection frame  21  is formed to have a predetermined length in the width direction of the vehicle and engaged with the transverse frame  22  in a center portion of the transverse frame  22 , and the articulated plate  32  is engaged with the connection frame  21 . 
     The transverse reinforcement frames  22 F and  22 R are provided parallel to the transverse frame  22 . The plurality of transverse reinforcement frames  22 F and  22 R are provided and provided with an interval from each other in the longitudinal direction of the vehicle. 
     Furthermore, the longitudinal reinforcement frames  23 FI,  23 FO,  23 RI, and  23 RO are provided parallel to the longitudinal frame  23 . The plurality of longitudinal reinforcement frames  23 FI,  23 FO,  23 RI, and  23 RO are provided and provided in the width direction of the vehicle. 
     The transverse reinforcement frames  22 F and  22 R include a first transverse reinforcement frame  22 F provided with an interval from the transverse frame  22 , and a second transverse reinforcement frame  22 R provided with an interval from the first transverse reinforcement frame  22 F in a rear side of the vehicle. The first transverse reinforcement frame  22 F and the second transverse reinforcement frame  22 R are sequentially provided toward the rear side of the vehicle from the transverse frame  22  located on the front end portion of the rear body  20  and transfer a load, which is input to the transverse frame  22  located at the front end portion of the rear body  20 , to the first transverse reinforcement frame  22 F and the second transverse reinforcement frame  22 R. 
     Both end portions of each of the first transverse reinforcement frame  22 F and the second transverse reinforcement frame  22 R are bonded to the longitudinal frame  23  by welding. 
     Since the longitudinal reinforcement frames  23 FI,  23 FO,  23 RI, and  23 RO are respectively provided between the transverse frame  22  located at the front end portion of the rear body  20  and the first transverse reinforcement frame  22 F and between the first transverse reinforcement frame  22 F and the second transverse reinforcement frame  22 R, the load input to the front end portion of the rear body  20  passes through the first transverse reinforcement frame  22 F and the second transverse reinforcement frame  22 R through the longitudinal reinforcement frames  23 FI,  23 FO,  23 RI, and  23 RO to be transferred toward the rear end portion of the rear body  20 . 
     The longitudinal reinforcement frames  23 FI,  23 FO,  23 RI, and  23 RO include internal longitudinal reinforcement frame  23 FI and  23 RI provided adjacent to a center portion of the transverse frame  22  in the width direction, and external longitudinal reinforcement frames  23 FO and  23 RO provided in a direction of an external side of the vehicle from the internal longitudinal reinforcement frame  23 FI and  23 RI. 
     The internal longitudinal reinforcement frames  23 FI and  23 RI include a first internal longitudinal reinforcement frame  23 FI of which a front end portion is bonded to the transverse frame  22  and a rear end portion is bonded to the first transverse reinforcement frame  22 F, and a second internal longitudinal reinforcement frame  23 RI of which a front end portion is bonded to the first transverse reinforcement frame  22 F and a rear end portion is bonded to the second transverse reinforcement frame  22 R. The first internal longitudinal reinforcement frame  23 FI and the second internal longitudinal reinforcement frame  23 RI are provided on an imaginary line formed in the longitudinal direction of the vehicle to form the load transfer path. 
     Furthermore, the external longitudinal reinforcement frames  23 FO and  23 RO include a first external longitudinal reinforcement frame  23 FO of which a front end portion is bonded to the transverse frame  22  and a rear end portion is bonded to the first transverse reinforcement frame  22 F, and a second external longitudinal reinforcement frame  23 RO of which a front end portion is bonded to the first transverse reinforcement frame  22 F and a rear end portion is bonded to the second transverse reinforcement frame  22 R. The first external longitudinal reinforcement frame  23 FO and the second external longitudinal reinforcement frame  23 RO are provided on an imaginary line formed in the longitudinal direction of the vehicle to form the load transfer path. 
     As shown in  FIG.  5   , the first internal longitudinal reinforcement frame  23 FI, the second internal longitudinal reinforcement frame  23 RI, the first external longitudinal reinforcement frame  23 FO, and the second external longitudinal reinforcement frame  23 RO form load transfer paths to transfer the load input through the transverse frame  22  to the rear body  20  toward the rear side of the vehicle. 
     The first internal longitudinal reinforcement frame  23 FI and the second internal longitudinal reinforcement frame  23 RI may be located inside an area in which the connection frame  21  is provided, whereas the first external longitudinal reinforcement frame  23 FO and the second external longitudinal reinforcement frame  23 RO may be located outside the area in which the connection frame  21  is provided. 
     The first internal longitudinal reinforcement frame  23 FI, the second internal longitudinal reinforcement frame  23 RI, the first external longitudinal reinforcement frame  23 FO, and the second external longitudinal reinforcement frame  23 RO are bonded to the transverse frame  22 , the first transverse reinforcement frame  22 F, and the second transverse reinforcement frame  22 R by welding. The first transverse reinforcement frame  22 F, the second transverse reinforcement frame  22 R, the first internal longitudinal reinforcement frame  23 FI, the second internal longitudinal reinforcement frame  23 RI, the first external longitudinal reinforcement frame  23 FO, and the second external longitudinal reinforcement frame  23 RO are each formed in a form of a tube including a rectangular cross section, and each end portion thereof is bonded by welding. 
     Meanwhile, to receive the load input from the articulated unit to the rear body  20  through a large area, reinforcement members  24  configured to reinforce bonding stiffness between the external longitudinal reinforcement frames  23 FO and  23 RO and the transverse frame  22  may be provided in portions in which the external longitudinal reinforcement frames  23 FO and  23 RO are bonded to the transverse frame  22 . 
     The reinforcement member  24  is provided in a portion in which the first external longitudinal reinforcement frame  23 FO is bonded to the transverse frame  22  to reinforce the bonding stiffness between the first external longitudinal reinforcement frame  23 FO and the transverse frame  22 . The reinforcement member  24  is formed to connect one side of the first external longitudinal reinforcement frame  23 FO to one side of the transverse frame  22 . The reinforcement member  24  is formed in a form of a triangle in a plan view, and a length of the reinforcement member  24  is formed to be greater than a width thereof. Furthermore, a width W2 of the reinforcement member  24  is formed to be the same as a width W1 of the first external longitudinal reinforcement frame  23 FO. As shown in  FIG.  7   , when the first external longitudinal reinforcement frame  23 FO is bonded to the transverse frame  22  without the reinforcement member  24 , stress is concentrated in a bonding portion (an area indicated by C in  FIG.  7   ), and thus shearing may occur. To prevent the shearing, the reinforcement member  24  is provided between the first external longitudinal reinforcement frame  23 FO and the transverse frame  22  to distribute the stress. 
     Furthermore, patch members  25  are provided to increase a welding length, improving the bonding stiffness. 
     The patch member  25  are provided in a portion in which the first internal longitudinal reinforcement frame  23 FI is bonded to the first transverse reinforcement frame  22 F, and a portion in which the second internal longitudinal reinforcement frame  23 RI and the second external longitudinal reinforcement frame  23 RO are bonded to the first transverse reinforcement frame  22 F or the second transverse reinforcement frame  22 R. For example, as shown in  FIG.  8   , due to the patch members  25 , a welding length of a welding portion W between the second internal longitudinal reinforcement frame  23 RI and the first transverse reinforcement frame  22 F is increased, and thus the bonding stiffness therebetween is improved. A width W3 of the patch member  25  is formed to be narrower than a width of the first internal longitudinal reinforcement frame  23 FI, a width of the second internal longitudinal reinforcement frame  23 RI, and the width W1 of the second external longitudinal reinforcement frame. A width W3 of the patch member  25  may be preferable to be at least half, for example, from 50% to 100%, than the width of the first internal longitudinal reinforcement frame  23 FI, the width of the second internal longitudinal reinforcement frame  23 RI, and the width W2 of the second external longitudinal reinforcement frame. 
     To stably transfer the load input to the rear body  20  to the rear side of the rear body  20  through the transverse reinforcement frames  22 F and  22 R and the longitudinal reinforcement frames  23 FI,  23 FO,  23 RI, and  23 RO, a rear center frame member  26  is included. 
     The rear center frame member  26  is located at the rear side of the vehicle rather than the second internal longitudinal reinforcement frame  23 RI and forms a load transfer path together with the first internal longitudinal reinforcement frame  23 FI and the second internal longitudinal reinforcement frame  23 RI. 
     The rear center frame member  26  is provided on an imaginary line formed in the longitudinal direction of the vehicle together with the first internal longitudinal reinforcement frame  23 FI and the second internal longitudinal reinforcement frame  23 RI. When the rear center frame member  26  is provided as described above, the load which is input through the first internal longitudinal reinforcement frame  23 FI and the second internal longitudinal reinforcement frame  23 RI may be stably transferred to the rear side of the rear body  20  through the rear center frame member  26 . 
     In accordance with a stiffness improvement structure of a vehicle according to an exemplary embodiment of the present disclosure, which has the above-described configuration, a reinforcement member is added to a bonding portion between a transverse frame and a longitudinal frame which form a rear body so that stiffness of the rear body may be improved. 
     Furthermore, during traveling, a transfer path of a load input from an articulated unit is distributed so that it is possible to prevent a phenomenon in which stress is concentrated in a portion of the rear body, preventing the rear body from being sheared. 
     For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner”, “outer”, “up”, “down”, “upwards”, “downwards”, “front”, “rear”, “back”, “inside”, “outside”, “inwardly”, “outwardly”, “interior”, “exterior”, “internal”, “external”, “forwards”, and “backwards” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. It will be further understood that the term “connect” or its derivatives refer both to direct and indirect connection. 
     The foregoing descriptions of predetermined exemplary embodiments of the present disclosure have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to enable others skilled in the art to make and utilize various exemplary embodiments of the present disclosure, as well as various alternatives and modifications thereof. It is intended that the scope of the present disclosure be defined by the Claims appended hereto and their equivalents.